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Zhou Q, Fan S, Lei KM, Ham D, Martins RP, Mak PI. Miniature Magnetic Resonance Imaging System for in Situ Monitoring of Bacterial Growth and Biofilm Formation. IEEE Trans Biomed Circuits Syst 2024; PP:1-11. [PMID: 38393852 DOI: 10.1109/tbcas.2024.3369389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
In situ monitoring of bacterial growth can greatly benefit human healthcare, biomedical research, and hygiene management. Magnetic resonance imaging (MRI) offers two key advantages in tracking bacterial growth: non-invasive monitoring through opaque sample containers and no need for sample pretreatment such as labeling. However, the large size and high cost of conventional MRI systems are the roadblocks for in situ monitoring. Here, we proposed a small, portable MRI system by combining a small permanent magnet and an integrated radio-frequency (RF) electronic chip that excites and reads out nuclear spin motions in a sample, and utilize this small MRI platform for in situ imaging of bacterial growth and biofilm formation. We demonstrate that MRI images taken by the miniature--and thus broadly deployable for in situ work--MRI system provide information on the spatial distribution of bacterial density, and a sequential set of MRI images taken at different times inform the temporal change of the spatial map of bacterial density, showing bacterial growth.
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Wan L, Li M, Law MK, Mak PI, Martins RP, Jia Y. Sub-5-Minute Ultrafast PCR using Digital Microfluidics. Biosens Bioelectron 2023; 242:115711. [PMID: 37797533 DOI: 10.1016/j.bios.2023.115711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 09/08/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023]
Abstract
The development of a rapid and reliable polymerase chain reaction (PCR) method for point-of-care (POC) diagnosis is crucial for the timely identification of pathogens. Microfluidics, which involves the manipulation of small volumes of fluidic samples, has been shown to be an ideal approach for POC analysis. Among the various microfluidic platforms available, digital microfluidics (DMF) offers high degree of configurability in manipulating μL/nL-scale liquid and achieving automation. However, the successful implementation of ultrafast PCR on DMF platforms presents challenges due to inherent system instability. In this study, we developed a robust and ultrafast PCR in 3.7-5 min with a detection sensitivity comparable to conventional PCR. Specifically, the implementation of the pincer heating scheme homogenises the temperature within a drop. The utilization of a μm-scale porous hydrophobic membrane suppresses the formation of bubbles under high temperatures. The design of a groove around the high-temperature zone effectively mitigates the temperature interference. The integration of a soluble sensor into the droplets provides an accurate and instant in-drop temperature sensing. We envision that the fast, robust, sensitive, and automatic DMF system will empower the POC testing for infectious diseases.
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Affiliation(s)
- Liang Wan
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China
| | - Mingzhong Li
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China; Silergy Semiconductor (Macau) Limited, Macao, China
| | - Man-Kay Law
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China; Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Pui-In Mak
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China; Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Rui P Martins
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China; Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China; On Leave from Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Yanwei Jia
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao, China; Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China; MoE Frontiers Science Center for Precision Oncology, University of Macau, Macao, China.
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Dong C, Li F, Sun Y, Long D, Chen C, Li M, Wei T, Martins RP, Chen T, Mak PI. A syndromic diagnostic assay on a macrochannel-to-digital microfluidic platform for automatic identification of multiple respiratory pathogens. Lab Chip 2023. [PMID: 37961846 DOI: 10.1039/d3lc00728f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The worldwide COVID-19 pandemic has changed people's lives and the diagnostic landscape. The nucleic acid amplification test (NAT) as the gold standard for SARS-CoV-2 detection has been applied in containing its transmission. However, there remains a lack of an affordable on-site detection system at resource-limited areas. In this study, a low cost "sample-in-answer-out" system incorporating nucleic acid extraction, purification, and amplification was developed on a single macrochannel-to-digital microfluidic chip. The macrochannel fluidic subsystem worked as a world-to-chip interface receiving 500-1000 μL raw samples, which then underwent bead-based extraction and purification processes before being delivered to DMF. Electrodes actuate an eluent dispensed to eight independent droplets for reverse transcription quantitative polymerase chain reaction (RT-qPCR). By reading with 4 florescence channels, the system can accommodate a maximum of 32 detection targets. To evaluate the proposed platform, a comprehensive assessment was conducted on the microfluidic chip as well as its functional components (i.e., extraction and amplification). The platform demonstrated a superior performance. In particular, using clinical specimens, the chip targeting SARS-CoV-2 and Flu A/B exhibited 100% agreement with off-chip diagnoses. Furthermore, the fabrication of chips is ready for scaled-up manufacturing and they are cost-effective for disposable use since they are assembled using a printed circuit board (PCB) and prefabricated blocks. Overall, the macrochannel-to-digital microfluidic platform coincides with the requirements of point-of-care testing (POCT) because of its advantages: low-cost, ease of use, comparable sensitivity and specificity, and availability for mass production.
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Affiliation(s)
- Cheng Dong
- School of Intelligent Systems Science and Engineering/JNU-Industry School of Artificial Intelligence, Jinan University, Zhuhai 519000, China
| | - Fei Li
- Department of Biomedical Engineering, Jinan University, Guangzhou, 510632, China
- Digifluidic Biotech Ltd., Zhuhai 519000, China.
| | - Yun Sun
- Digifluidic Biotech Ltd., Zhuhai 519000, China.
| | - Dongling Long
- Zhuhai Center for Disease Control and Prevention, Zhuhai 519087, China
| | - Chunzhao Chen
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhu Hai 519087, China
| | - Mengyan Li
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, 07102, USA
| | - Tao Wei
- Department of Bioengineering, College of Food Science, South China Agricultural University, Guangzhou, 510640, China
- Pan Asia (Jiangmen) Institute of Biological Engineering and Health, Jiangmen, 529080, China
| | - Rui P Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macau SAR, 999078, China.
| | | | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macau SAR, 999078, China.
- Faculty of Science and Technology, University of Macau, Taipa, Macau SAR, 999078, China
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Li H, Peng T, Zhong Y, Liu M, Mak PI, Martins RP, Wang P, Jia Y. pH Regulator on Digital Microfluidics with Pico-Dosing Technique. Biosensors (Basel) 2023; 13:951. [PMID: 37998126 PMCID: PMC10669492 DOI: 10.3390/bios13110951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/01/2023] [Accepted: 09/03/2023] [Indexed: 11/25/2023]
Abstract
Real-time pH control on-chip is a crucial factor for cell-based experiments in microfluidics, yet difficult to realize. In this paper, we present a flexible pH regulator on a digital microfluidic (DMF) platform. The pico-dosing technology, which can generate and transfer satellite droplets, is presented to deliver alkali/acid into the sample solution to change the pH value of the sample. An image analysis method based on ImageJ is developed to calculate the delivered volume and an on-chip colorimetric method is proposed to determine the pH value of the sample solution containing the acid-base indicator. The calculated pH values show consistency with the measured ones. Our approach makes the real-time pH control of the on-chip biological experiment more easy to control and flexible.
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Affiliation(s)
- Haoran Li
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (H.L.); (M.L.); (P.-I.M.)
| | - Tao Peng
- Zhuhai UM Science & Technology Research Institute, Zhuhai 519085, China;
| | - Yunlong Zhong
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Meiqing Liu
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (H.L.); (M.L.); (P.-I.M.)
| | - Pui-In Mak
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (H.L.); (M.L.); (P.-I.M.)
- Zhuhai UM Science & Technology Research Institute, Zhuhai 519085, China;
| | - Rui P. Martins
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (H.L.); (M.L.); (P.-I.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
- Instituto Superior Técnico, Unversidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Ping Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China
| | - Yanwei Jia
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (H.L.); (M.L.); (P.-I.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau 999078, China
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Shen R, Lv A, Yi S, Wang P, Mak PI, Martins RP, Jia Y. Nucleic acid analysis on electrowetting-based digital microfluidics. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Pakkirisami Churchill KK, Ramiah H, Chong G, Chen Y, Mak PI, Martins RP. A Fully-Integrated Ambient RF Energy Harvesting System with 423-μW Output Power. Sensors (Basel) 2022; 22:4415. [PMID: 35746197 PMCID: PMC9227311 DOI: 10.3390/s22124415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
This paper proposes a 2.4-GHz fully-integrated single-frequency multi-channel RF energy harvesting (RFEH) system with increased harvested power density. The RFEH can produce an output power of ~423-μW in harvesting ambient RF energy. The front-end consists of an on-chip impedance matching network with a stacked rectifier concurrently matched to a 50 Ω input source. The circuit mitigates the "dead-zone" by enhancing the pumping efficiency, achieved through the increase of Vgs drivability of the proposed internal gate boosting 6-stage low-input voltage charge pump and the 5-stage shared-auxiliary-biasing ring-voltage-controlled-oscillator (VCO) integrated to improve the start-up. The RFEH system, simulated in 180-nm complementary metal-oxide-semiconductor (CMOS), occupies an active area of 1.02 mm2. Post-layout simulations show a peak power conversion efficiency(PCE) of 21.15%, driving a 3.3-kΩ load at an input power of 0 dBm and sensitivity of -14.1 dBm corresponding to an output voltage, Vout,RFEH of 1.25 V.
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Affiliation(s)
| | - Harikrishnan Ramiah
- Centre of Research Industry 4.0 (CRI 4.0), Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | | | - Yong Chen
- State-Key Laboratory of Analog and Mixed-Signal VLSI/IME, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China; (Y.C.); (P.-I.M.); (R.P.M.)
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI/IME, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China; (Y.C.); (P.-I.M.); (R.P.M.)
| | - Rui P. Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI/IME, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China; (Y.C.); (P.-I.M.); (R.P.M.)
- Instituto Superior Técnico, Universidade de Lisboa, 1099-085 Lisboa, Portugal
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Li M, Wan L, Law MK, Meng L, Jia Y, Mak PI, Martins RP. One-shot high-resolution melting curve analysis for KRAS point-mutation discrimination on a digital microfluidics platform. Lab Chip 2022; 22:537-549. [PMID: 34904611 DOI: 10.1039/d1lc00564b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Single-nucleotide polymorphism (SNP) plays a critical role in personalized medicine, forensics, pharmacogenetics, and disease diagnostics. Among different existing SNP genotyping techniques, melting curve analysis (MCA) becomes increasingly popular due to its high accuracy and straightforward procedures in extracting the melting temperature (Tm). Yet, its study on existing digital microfluidic (DMF) platforms has intrinsic limitations due to the temperature inhomogeneity within a thickened droplet during the on-chip rapid heating process. Although the utilization of an on-chip thermostat can regulate and monitor the dynamic melting process in real time, the limited Tm accuracy resulting from the insufficient system response time to accommodate the fast-melting evolution still poses a great challenge for precise MCA with high throughput. This work proposes a one-shot MCA on a DMF platform. The tailoring of a functional substrate with hierarchical micro/nano structure enables high-resolution patterning of pL-scale droplets. Specifically, the hydrothermal and photocatalysis treatment allows the functional substrate to exhibit a superwettability contrast of >170°, facilitating passive isolation of the pL-scale DNA sample into highly-resolved pL droplets above the 200 μm superhydrophilic patterns. This high-resolution MCA technique can successfully discriminate KRAS gene targets with single-nucleotide mutations in 3 seconds. The high accuracy and consistency in the acquired Tm when compared with off-chip results demonstrate its opportunities for near-patient diagnostics, precision medicines, genetic counseling, and prevention strategies on DMF platforms.
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Affiliation(s)
- Mingzhong Li
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
| | - Liang Wan
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Man-Kay Law
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Li Meng
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Yanwei Jia
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Pui-In Mak
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
| | - Rui P Martins
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Taipa, Macao, China.
- Faculty of Science and Technology - Electrical and Computer Engineering, University of Macau, Macao, China
- On leave from Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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Zhai J, Li C, Li H, Yi S, Yang N, Miao K, Deng C, Jia Y, Mak PI, Martins RP. Cancer drug screening with an on-chip multi-drug dispenser in digital microfluidics. Lab Chip 2021; 21:4749-4759. [PMID: 34761772 DOI: 10.1039/d1lc00895a] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Microfluidics has been the most promising platform for drug screening with a limited number of cells. However, convenient on-chip preparation of a wide range of drug concentrations remains a large challenge and has restricted wide acceptance of microfluidics in precision medicine. In this paper, we report a digital microfluidic system with an innovative control structure and chip design for on-chip drug dispensing to generate concentrations that span three to four orders of magnitude, enabling single drug or combinatorial multi-drug screening with simple electronic control. Specifically, we utilize droplet ejection from a drug drop sitting on a special electrode, named a drug dispenser, under high-voltage pulse actuation to deliver the desired amount of drugs to be picked up by a cell suspension drop driven by low-voltage sine wave actuation. Our proof-of-principle validation for this technique as a convenient single and multi-drug screening involved testing of the drug toxicity of two chemotherapeutics, cisplatin (Cis) and epirubicin (EP), towards MDA-MB-231 breast cancer cells and MCF-10A normal breast cells. The results are consistent with those screened based on traditional 96-well plates. These findings demonstrate the reliability of the drug screening system with an on-chip drug dispenser. This system with fewer cancer cells, less drug consumption, a small footprint, and high scalability with regard to concentration could pave the way for drug screening on biopsied primary tumor cells for precision medicine or any concentration-related research.
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Affiliation(s)
- Jiao Zhai
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Department of Biomedical Sciences/Tung Biomedical Sciences Centre, City University of Hong Kong, Hong Kong, China
| | - Caiwei Li
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Faculty of Science and Technology - DECE, University of Macau, Macau, China
| | - Haoran Li
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Faculty of Science and Technology - DECE, University of Macau, Macau, China
| | - Shuhong Yi
- Liver Transplantation Center, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ning Yang
- Department of Electronic Information Engineering, Jiangsu University, Zhenjiang, China
| | - Kai Miao
- Faculty of Health Sciences, University of Macau, Macau, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau, China
| | - Chuxia Deng
- Faculty of Health Sciences, University of Macau, Macau, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau, China
| | - Yanwei Jia
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Faculty of Science and Technology - DECE, University of Macau, Macau, China
- Faculty of Health Sciences, University of Macau, Macau, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau, China
| | - Pui-In Mak
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Faculty of Science and Technology - DECE, University of Macau, Macau, China
| | - Rui P Martins
- State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China.
- Faculty of Science and Technology - DECE, University of Macau, Macau, China
- On leave from Instituto Superior Tecnico, Universidade de Lisboa, Portugal
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Rebouças TO, Martins RP, Firmeza JS, Loiola DEL, Azevedo IC. TREINAMENTO EM BIOSSEGURANÇA NA HEMORREDE DO CEARÁ. Hematol Transfus Cell Ther 2021. [DOI: 10.1016/j.htct.2021.10.789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Hartmann DD, Martins RP, Silva TCD, Stefanello ST, Courtes AA, Gonçalves DF, Furtado ABV, Duarte BSL, Signori LU, Soares FAA, Puntel GO. Oxidative stress is involved in LLLT mechanism of action on skin healing in rats. ACTA ACUST UNITED AC 2021; 54:e10293. [PMID: 33909854 PMCID: PMC8075128 DOI: 10.1590/1414-431x202010293] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 01/21/2021] [Indexed: 01/24/2023]
Abstract
The skin injury healing process involves the main phases of homoeostasis, inflammation, proliferation, and remodeling. The present study aimed to analyze the effects of low-level laser therapy (LLLT) on hematological dynamics, oxidative stress markers, and its relation with tissue healing following skin injury. Wistar rats were divided into control, sham, skin injury, and skin injury LLLT. The biochemical and morphological analyses were performed in the inflammatory (1 and 3 days) and regenerative phases (7, 14, and 21 days) following injury. The skin injury was performed in the dorsal region, between the intrascapular lines, using a surgical punch. LLLT (Al-Ga-In-P, λ=660 nm, energy density of 20 J/cm2, 30 mW power, and a time of 40 s) was applied at the area immediately after injury and on every following day according to the experimental subgroups. LLLT maintained hematocrit and hemoglobin levels until the 3rd day of treatment. Surprisingly, LLLT increased total leukocytes levels compared to control until the 3rd day. The effects of LLLT on mitochondrial activity were demonstrated by the significant increase in MTT levels in both inflammatory and regenerative phases (from the 1st to the 7th day), but only when associated with skin injury. The results indicated that LLLT modulated the inflammatory response intensity and accelerated skin tissue healing by a mechanism that involved oxidative damage reduction mostly at early stages of skin healing (inflammatory phase).
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Affiliation(s)
- D D Hartmann
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - R P Martins
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - T C da Silva
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - S T Stefanello
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - A A Courtes
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - D F Gonçalves
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - A B V Furtado
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas e Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - B S L Duarte
- Centro de Ciências da Saúde, Departamento de Fisioterapia, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - L U Signori
- Centro de Ciências da Saúde, Departamento de Fisioterapia, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - F A A Soares
- Centro de Ciências Naturais e Exatas, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - G O Puntel
- Centro de Ciências da Saúde, Departamento de Morfologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
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Liu M, Li H, Jia Y, Mak PI, Martins RP. SARS-CoV-2 RNA Detection with Duplex-Specific Nuclease Signal Amplification. Micromachines (Basel) 2021; 12:197. [PMID: 33672890 PMCID: PMC7918681 DOI: 10.3390/mi12020197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 12/23/2022]
Abstract
The emergence of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a zoonotic pathogen, has led to the outbreak of coronavirus disease 2019 (COVID-19) pandemic and brought serious threats to public health worldwide. The gold standard method for SARS-CoV-2 detection requires both reverse transcription (RT) of the virus RNA to cDNA and then polymerase chain reaction (PCR) for the cDNA amplification, which involves multiple enzymes, multiple reactions and a complicated assay optimization process. Here, we developed a duplex-specific nuclease (DSN)-based signal amplification method for SARS-CoV-2 detection directly from the virus RNA utilizing two specific DNA probes. These specific DNA probes can hybridize to the target RNA at different locations in the nucleocapsid protein gene (N gene) of SARS-CoV-2 to form a DNA/RNA heteroduplex. DSN cleaves the DNA probe to release fluorescence, while leaving the RNA strand intact to be bound to another available probe molecule for further cleavage and fluorescent signal amplification. The optimized DSN amount, incubation temperature and incubation time were investigated in this work. Proof-of-principle SARS-CoV-2 detection was demonstrated with a detection sensitivity of 500 pM virus RNA. This simple, rapid, and direct RNA detection method is expected to provide a complementary method for the detection of viruses mutated at the PCR primer-binding regions for a more precise detection.
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Affiliation(s)
- Meiqing Liu
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (M.L.); (H.L.); (P.-I.M.); (R.P.M.)
| | - Haoran Li
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (M.L.); (H.L.); (P.-I.M.); (R.P.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
| | - Yanwei Jia
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (M.L.); (H.L.); (P.-I.M.); (R.P.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
- Faculty of Health Sciences, University of Macau, Macau 999078, China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (M.L.); (H.L.); (P.-I.M.); (R.P.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
| | - Rui P. Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau 999078, China; (M.L.); (H.L.); (P.-I.M.); (R.P.M.)
- Faculty of Science and Technology–ECE, University of Macau, Macau 999078, China
- On Leave from Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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12
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Li H, Shen R, Dong C, Chen T, Jia Y, Mak PI, Martins RP. Turning on/off satellite droplet ejection for flexible sample delivery on digital microfluidics. Lab Chip 2020; 20:3709-3719. [PMID: 32974634 DOI: 10.1039/d0lc00701c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Digital microfluidics has the potential to minimize and automate reactions in biochemical labs. However, the complexity of drop manipulation and sample preparation on-chip has limited its incorporation into daily workflow. In this paper, we report a novel method for flexible sample delivery on digital microfluidics in a wide volume range spanning four orders of magnitude from picoliters to nanoliters. The method is based on the phenomenon of satellite droplet ejection, triggered by a sudden change in the strength of the electric field across a drop on a hydrophobic dielectric surface. By precisely modulating the actuation signal with convenient external electric controls, satellite droplet ejection can be turned on to dispense samples or turned off to transport picking-up drops. A pico-dosing design is presented and validated in this work to demonstrate the direct and flexible on-chip sample delivery. This approach could pave the way for the acceptance of microfluidics as a common platform for daily reactions to realize lab-on-a-chip.
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Affiliation(s)
- Haoran Li
- The State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China.
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13
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Zhai J, Li H, Wong AHH, Dong C, Yi S, Jia Y, Mak PI, Deng C, Martins RP. A Novel and Robust Single-cell Trapping Method on Digital Microfluidics. Bio Protoc 2020; 10:e3769. [PMID: 33659427 PMCID: PMC7842684 DOI: 10.21769/bioprotoc.3769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/29/2020] [Accepted: 07/22/2020] [Indexed: 11/02/2022] Open
Abstract
Due to cell heterogeneity, the differences among individual cells are averaged out in bulk analysis methods, especially in the analysis of primary tumor biopsy samples from patients. To deeply understand the cell-to-cell variation in a primary tumor, single-cell culture and analysis with limited amount of cells are in high demand. Microfluidics has been an optimum platform to address the issue given its small reaction volume requirements. Digital microfluidics, which utilizes an electric signal to manipulate individual droplets has shown promise in cell-culture with easy controls. In this work, we realize single cell trapping on digital microfluidic platform by fabricating 3D microstructures on-chip to form semi-closed micro-wells. With this design, 20% of 30 x 30 array can be occupied by isolated single cells. We also use a low evaporation silicon oil and a fluorinated surfactant to lower the droplet actuation voltage and prevent the drop from evaporation, while allowing cell respiration during the long term of culture (24 h). The main steps for single cell trapping on digital microfluidics, as illustrated in this protocol, include 3D microstructures design, 3D microstructures construction on chip and oil film with surfactant for single cell trapping on chip.
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Affiliation(s)
- Jiao Zhai
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
| | - Haoran Li
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
| | - Ada Hang-Heng Wong
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau, China
| | - Cheng Dong
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
| | - Shuhong Yi
- Liver Transplantation Center, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Yanwei Jia
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau, China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
| | - Chuxia Deng
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau, China
| | - Rui P. Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macao SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
- Instituto Superior Técnico, Universidade de Lisboa, Portugal
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Shen R, Jia Y, Mak PI, Martins RP. Clip-to-release on amplification (CRoA): a novel DNA amplification enhancer on and off microfluidics. Lab Chip 2020; 20:1928-1938. [PMID: 32352133 DOI: 10.1039/d0lc00318b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Despite its high sensitivity, low cost, and high efficiency as a DNA amplification indicator with a yes/no answer, dsDNA-binding dye encounters incompatibility when used in microfluidic systems, resulting in problems such as false negative amplification results. Besides, its inhibition of amplification at high concentrations hinders its application both on-chip and off-chip. In this study, we propose a novel DNA amplification enhancer to counteract the drawbacks of dsDNA-binding dyes. It acts as a temporary reservoir for the free-floating dyes in solution and releases them on demand during the amplification process. Through this clip-to-release on amplification mechanism, the enhancer lowered the background fluorescence of sample droplets before amplification, enhanced the signal-to-background ratio of positive samples, and eliminated the false negative signal of on-chip PCR. Moreover, the enhancer increased the off-chip polymerase chain reaction (PCR) efficiency, boosted the fluorescence signal up to 10-fold, and made less nonspecific amplification product. All the factors affecting the enhancer's performance are investigated in detail, including its structure and concentration, and the types of dsDNA-binding dye used in the reaction. Finally, we demonstrated the broad application of the proposed amplification enhancer in various DNA amplification systems, for various genes, and on various amplification platforms. It would reignite the utilization of dsDNA dyes for wider applications in DNA analysis both on-chip and off-chip.
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Affiliation(s)
- Ren Shen
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China. and Faculty of Science and Technology - ECE, University of Macau, Macau, China
| | - Yanwei Jia
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China. and Faculty of Science and Technology - ECE, University of Macau, Macau, China and Faculty of Health Sciences, University of Macau, Macau, China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China. and Faculty of Science and Technology - ECE, University of Macau, Macau, China
| | - Rui P Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau, China. and Faculty of Science and Technology - ECE, University of Macau, Macau, China and On Leave from Instituto Superior Técnico, Universidade de Lisboa, Portugal
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15
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Zhai J, Li H, Wong AHH, Dong C, Yi S, Jia Y, Mak PI, Deng CX, Martins RP. A digital microfluidic system with 3D microstructures for single-cell culture. Microsyst Nanoeng 2020; 6:6. [PMID: 34567621 PMCID: PMC8433300 DOI: 10.1038/s41378-019-0109-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/12/2019] [Accepted: 09/30/2019] [Indexed: 05/12/2023]
Abstract
Despite the precise controllability of droplet samples in digital microfluidic (DMF) systems, their capability in isolating single cells for long-time culture is still limited: typically, only a few cells can be captured on an electrode. Although fabricating small-sized hydrophilic micropatches on an electrode aids single-cell capture, the actuation voltage for droplet transportation has to be significantly raised, resulting in a shorter lifetime for the DMF chip and a larger risk of damaging the cells. In this work, a DMF system with 3D microstructures engineered on-chip is proposed to form semi-closed micro-wells for efficient single-cell isolation and long-time culture. Our optimum results showed that approximately 20% of the micro-wells over a 30 × 30 array were occupied by isolated single cells. In addition, low-evaporation-temperature oil and surfactant aided the system in achieving a low droplet actuation voltage of 36V, which was 4 times lower than the typical 150 V, minimizing the potential damage to the cells in the droplets and to the DMF chip. To exemplify the technological advances, drug sensitivity tests were run in our DMF system to investigate the cell response of breast cancer cells (MDA-MB-231) and breast normal cells (MCF-10A) to a widely used chemotherapeutic drug, Cisplatin (Cis). The results on-chip were consistent with those screened in conventional 96-well plates. This novel, simple and robust single-cell trapping method has great potential in biological research at the single cell level.
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Affiliation(s)
- Jiao Zhai
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
| | - Haoran Li
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
| | - Ada Hang-Heng Wong
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Cheng Dong
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
| | - Shuhong Yi
- Liver Transplantation Center, the Third Affiliated Hospital, Sun Yat-sen University, 510000 Guangzhou, China
| | - Yanwei Jia
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
| | - Chu-Xia Deng
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Rui P. Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, University of Macau, Macau SAR, China
- Faculty of Science and Technology-ECE, University of Macau, Macau SAR, China
- on leave from Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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16
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Furtado ABV, Hartmann DD, Martins RP, Rosa PC, da Silva IK, Duarte BSL, Signori LU, Soares FAA, Puntel GO. Cryotherapy: biochemical alterations involved in reduction of damage induced by exhaustive exercise. ACTA ACUST UNITED AC 2018; 51:e7702. [PMID: 30304134 PMCID: PMC6172926 DOI: 10.1590/1414-431x20187702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 08/07/2018] [Indexed: 11/22/2022]
Abstract
When exercises are done in intense or exhaustive modes, several acute biochemical mechanisms are triggered. The use of cryotherapy as cold-water immersion is largely used to accelerate the process of muscular recovery based on its anti-inflammatory and analgesic properties. The present study aimed to study the biochemical effects of cold-water immersion treatment in mice submitted to exercise-induced exhaustion. Swiss albino mice were divided into 4 treatment groups: control, cold-water immersion (CWI), swimming exhaustive protocol (SEP), and SEP+CWI. Treatment groups were subdivided into times of analysis: 0, 1, 3, and 5 days. Exhaustion groups were submitted to one SEP session, and the CWI groups submitted to one immersion session (12 min at 12°C) every 24 h. Reactive species production, inflammatory, cell viability, and antioxidant status were assessed. The SEP+CWI group showed a decrease in inflammatory damage biomarkers, and reactive species production, and presented increased cell viability compared to the SEP group. Furthermore, CWI increased acetylcholinesterase activity in the first two sessions. The present study showed that CWI was an effective treatment after exercise-induced muscle damage. It enhanced anti-inflammatory response, decreased reactive species production, increased cell viability, and promoted redox balance, which could decrease the time for the recovery process.
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Affiliation(s)
- A B V Furtado
- Centro de Ciências da Saúde, Programa de Pós-graduação em Reabilitação Funcional, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - D D Hartmann
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - R P Martins
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - P C Rosa
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - I K da Silva
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - B S L Duarte
- Centro de Ciências da Saúde, Programa de Pós-graduação em Reabilitação Funcional, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - L U Signori
- Centro de Ciências da Saúde, Programa de Pós-graduação em Reabilitação Funcional, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - F A A Soares
- Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
| | - G O Puntel
- Centro de Ciências da Saúde, Programa de Pós-graduação em Reabilitação Funcional, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil.,Centro de Ciências Naturais e Exatas, Programa de Pós-Graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil.,Centro de Ciências da Saúde, Departamento de Morfologia, Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
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17
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Dong C, Jia Y, Gao J, Chen T, Mak PI, Vai MI, Martins RP. A 3D microblade structure for precise and parallel droplet splitting on digital microfluidic chips. Lab Chip 2017; 17:896-904. [PMID: 28194461 DOI: 10.1039/c6lc01539e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Existing digital microfluidic (DMF) chips exploit the electrowetting on dielectric (EWOD) force to perform droplet splitting. However, the current splitting methods are not flexible and the volume of the droplets suffers from a large variation. Herein, we propose a DMF chip featuring a 3D microblade structure to enhance the droplet-splitting performance. By exploiting the EWOD force for shaping and manipulating the mother droplet, we obtain an average dividing error of <2% in the volume of the daughter droplets for a number of fluids such as deionized water, DNA solutions and DNA-protein mixtures. Customized droplet splitting ratios of up to 20 : 80 are achieved by positioning the blade at the appropriate position. Additionally, by fabricating multiple 3D microblades on one electrode, two to five uniform daughter droplets can be generated simultaneously. Finally, by taking synthetic DNA targets and their corresponding molecular beacon probes as a model system, multiple potential pathogens that cause sepsis are detected rapidly on the 3D-blade-equipped DMF chip, rendering it as a promising tool for parallel diagnosis of diseases.
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Affiliation(s)
- Cheng Dong
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China. and Faculty of Science and Technology - ECE, University of Macau, Macao, China
| | - Yanwei Jia
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China.
| | - Jie Gao
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China.
| | - Tianlan Chen
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China.
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China. and Faculty of Science and Technology - ECE, University of Macau, Macao, China
| | - Mang-I Vai
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China. and Faculty of Science and Technology - ECE, University of Macau, Macao, China
| | - Rui P Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China. and Faculty of Science and Technology - ECE, University of Macau, Macao, China
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18
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Chen Z, Law MK, Mak PI, Martins RP. A Single-Chip Solar Energy Harvesting IC Using Integrated Photodiodes for Biomedical Implant Applications. IEEE Trans Biomed Circuits Syst 2017; 11:44-53. [PMID: 27529876 DOI: 10.1109/tbcas.2016.2553152] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, an ultra-compact single-chip solar energy harvesting IC using on-chip solar cell for biomedical implant applications is presented. By employing an on-chip charge pump with parallel connected photodiodes, a 3.5 × efficiency improvement can be achieved when compared with the conventional stacked photodiode approach to boost the harvested voltage while preserving a single-chip solution. A photodiode-assisted dual startup circuit (PDSC) is also proposed to improve the area efficiency and increase the startup speed by 77%. By employing an auxiliary charge pump (AQP) using zero threshold voltage (ZVT) devices in parallel with the main charge pump, a low startup voltage of 0.25 V is obtained while minimizing the reversion loss. A 4 Vin gate drive voltage is utilized to reduce the conduction loss. Systematic charge pump and solar cell area optimization is also introduced to improve the energy harvesting efficiency. The proposed system is implemented in a standard 0.18- [Formula: see text] CMOS technology and occupies an active area of 1.54 [Formula: see text]. Measurement results show that the on-chip charge pump can achieve a maximum efficiency of 67%. With an incident power of 1.22 [Formula: see text] from a halogen light source, the proposed energy harvesting IC can deliver an output power of 1.65 [Formula: see text] at 64% charge pump efficiency. The chip prototype is also verified using in-vitro experiment.
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Abstract
Complementary metal oxide semiconductor (CMOS) technology enables low-cost and large-scale integration of transistors and physical sensing materials on tiny chips (e.g., <1 cm2), seamlessly combining the two key functions of biosensors: transducing and signal processing. Recent CMOS biosensors unified different transducing mechanisms (impedance, fluorescence, and nuclear spin) and readout electronics have demonstrated competitive sensitivity for in vitro diagnosis, such as detection of DNA (down to 10 aM), protein (down to 10 fM), or bacteria/cells (single cell). Herein, we detail the recent advances in CMOS biosensors, centering on their key principles, requisites, and applications. Together, these may contribute to the advancement of our healthcare system, which should be decentralized by broadly utilizing point-of-care diagnostic tools.
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Affiliation(s)
- Ka-Meng Lei
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China. and Faculty of Science and Technology, Dept. of ECE, University of Macau, China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China. and Faculty of Science and Technology, Dept. of ECE, University of Macau, China
| | - Man-Kay Law
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China.
| | - Rui P Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China. and Faculty of Science and Technology, Dept. of ECE, University of Macau, China and On leave from Instituto Superior Técnico, Universidade de Lisboa, Portugal
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20
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Chen T, Jia Y, Dong C, Gao J, Mak PI, Martins RP. Sub-7-second genotyping of single-nucleotide polymorphism by high-resolution melting curve analysis on a thermal digital microfluidic device. Lab Chip 2016; 16:743-752. [PMID: 26781669 DOI: 10.1039/c5lc01533b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We developed a thermal digital microfluidic (T-DMF) device enabling ultrafast DNA melting curve analysis (MCA). Within 7 seconds, the T-DMF device succeeded in differentiating a melting point difference down to 1.6 °C with a variation of 0.3 °C in a tiny droplet sample (1.2 μL), which was 300 times faster and with 20 times less sample spending than the standard MCA (35 minutes, 25 μL) run in a commercial qPCR machine. Such a performance makes it possible for a rapid discrimination of single-nucleotide mutation relevant to prompt clinical decision-making. Also, aided by electronic intelligent control, the T-DMF device facilitates sample handling and pipelining in an automatic serial manner. An optimized oval-shaped thermal electrode is introduced to achieve high thermal uniformity. A device-sealing technique averts sample contamination and permits uninterrupted chemical/biological reactions. Simple fabrication using a single chromium layer fulfills both the thermal and typical transport electrode requirements. Capable of thermally modulating DNA samples with ultrafast MCA, this T-DMF device has the potential for a wide variety of life science analyses, especially for disease diagnosis and prognosis.
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Affiliation(s)
- Tianlan Chen
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China.
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21
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Lei KM, Mak PI, Law MK, Martins RP. A palm-size μNMR relaxometer using a digital microfluidic device and a semiconductor transceiver for chemical/biological diagnosis. Analyst 2016; 140:5129-37. [PMID: 26034784 DOI: 10.1039/c5an00500k] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we describe a micro-nuclear magnetic resonance (μNMR) relaxometer miniaturized to palm-size and electronically automated for multi-step and multi-sample chemical/biological diagnosis. The co-integration of microfluidic and microelectronic technologies enables an association between the droplet managements and μNMR assays inside a portable sub-Tesla magnet (1.2 kg, 0.46 Tesla). Targets in unprocessed biological samples, captured by specific probe-decorated magnetic nanoparticles (NPs), can be sequentially quantified by their spin-spin relaxation time (T2) via multiplexed μNMR screening. Distinct droplet samples are operated by a digital microfluidic device that electronically manages the electrowetting-on-dielectric effects over an electrode array. Each electrode (3.5 × 3.5 mm(2)) is scanned with capacitive sensing to locate the distinct droplet samples in real time. A cross-domain-optimized butterfly-coil-input semiconductor transceiver transduces between magnetic and electrical signals to/from a sub-10 μL droplet sample for high-sensitivity μNMR screening. A temperature logger senses the ambient temperature (0 to 40 °C) and a backend processor calibrates the working frequency for the transmitter to precisely excite the protons. In our experiments, the μNMR relaxometer quantifies avidin using biotinylated Iron NPs (Φ: 30 nm, [Fe]: 0.5 mM) with a sensitivity of 0.2 μM. Auto-handling and identification of two targets (avidin and water) are demonstrated and completed within 2.2 min. This μNMR relaxometer holds promise for combinatorial chemical/biological diagnostic protocols using closed-loop electronic automation.
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Affiliation(s)
- Ka-Meng Lei
- State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, China.
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22
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Abstract
A silane-based adhesion promoter suitable for a multi-dielectric-layer coating on a digital microfluidic chip is reported.
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Affiliation(s)
- Jie Gao
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Tianlan Chen
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Cheng Dong
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Yanwei Jia
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Pui-In Mak
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Mang-I. Vai
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
| | - Rui P. Martins
- State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- Avenida da Universidade
- Taipa
- China
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Coelho FF, Martins RP, Figueira JEC, Demetrio GR. Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil. BRAZ J BIOL 2014; 74:828-36. [DOI: 10.1590/1519-6984.04513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 10/25/2013] [Indexed: 11/22/2022] Open
Abstract
In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.
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Drumond MA, Guimarães AQ, El Bizri HR, Giovanetti LC, Sepúlveda DG, Martins RP. Life history, distribution and abundance of the giant earthworm Rhinodrilus alatus RIGHI 1971: conservation and management implications. BRAZ J BIOL 2014; 73:699-708. [PMID: 24789384 DOI: 10.1590/s1519-69842013000400004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 10/03/2012] [Indexed: 11/22/2022] Open
Abstract
Rhinodrilus alatus is an endemic giant earthworm of the Brazilian Cerrado hotspot used as live bait for about 80 years. The goal of this study was to gather ecological data about this species, which will support the establishment of management strategies. The life history, distribution and abundance of R. alatus were investigated in Cerrado, pastures and Eucalyptus plantation areas following the harvesting activities of the local extractors of this species. We found that this earthworm is abundant in all of the sampled areas, showing its resilience to land-use conversion. The Capture Per Unit Effort was 4.4 ± 5 individuals per 100 metres of transect and 5.6 ± 3 individuals per hour. The earthworm's annual cycle is markedly seasonal, with an aestivation period throughout the driest and coldest season of the year. Significant differences in the length and diameter of the body and in the diameter and depth of the aestivation chambers were found between the juveniles and adults. The distribution range of the species was expanded from two to 17 counties. The life history, abundance, distribution and resilience of R. alatus to certain perturbations are key elements to be considered in conservation and management strategies for this species.
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Affiliation(s)
- M A Drumond
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - H R El Bizri
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | - R P Martins
- Departamento de Biologia, Centro de Ciências, Universidade Federal do Ceará, CE, Brazil
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Abstract
We present a modular nuclear magnetic resonance–digital microfluidics (NMR–DMF) system as a portable diagnostic platform for miniaturized biological assays.
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Affiliation(s)
- Ka-Meng Lei
- State-Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- China
| | - Pui-In Mak
- State-Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- China
| | - Man-Kay Law
- State-Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- China
| | - Rui P. Martins
- State-Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE
- University of Macau
- China
- Instituto Superior Técnico
- University of Lisbon
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Jia Y, Mak PI, Massey C, Martins RP, Wangh LJ. Construction of a microfluidic chip, using dried-down reagents, for LATE-PCR amplification and detection of single-stranded DNA. Lab Chip 2013; 13:4635-4641. [PMID: 24113690 DOI: 10.1039/c3lc51049b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
LATE-PCR is an advanced form of non-symmetric PCR that efficiently generates single-stranded DNA which can readily be characterized at the end of amplification by hybridization to low-temperature fluorescent probes. We demonstrate here for the first time that monoplex and duplex LATE-PCR amplification and probe target hybridization can be carried out in double layered PDMS microfluidics chips containing dried reagents. Addition of a set of reagents during dry down overcomes the common problem of single-stranded oligonucleotide binding to PDMS. These proof-of-principle results open the way to construction of inexpensive point-of-care devices that take full advantage of the analytical power of assays built using LATE-PCR and low-temperature probes.
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Affiliation(s)
- Yanwei Jia
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
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Li MZ, Ieong CI, Law MK, Mak PI, Vai MI, Martins RP. Sub-threshold standard cell library design for ultra-low power biomedical applications. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2013:1454-7. [PMID: 24109972 DOI: 10.1109/embc.2013.6609785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Portable/Implantable biomedical applications usually exhibit stringent power budgets for prolonging battery life time, but loose operating frequency requirements due to small bio-signal bandwidths, typically below a few kHz. The use of sub-threshold digital circuits is ideal in such scenario to achieve optimized power/speed tradeoffs. This paper discusses the design of a sub-threshold standard cell library using a standard 0.18-µm CMOS technology. A complete library of 56 standard cells is designed and the methodology is ensured through schematic design, transistor width scaling and layout design, as well as timing, power and functionality characterization. Performance comparison between our sub-threshold standard cell library and a commercial standard cell library using a 5-stage ring oscillator and an ECG designated FIR filter is performed. Simulation results show that our library achieves a total power saving of 95.62% and a leakage power reduction of 97.54% when compared with the same design implemented by the commercial standard cell library (SCL).
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Zhang TT, Mak PI, Vai MI, Mak PU, Law MK, Pun SH, Wan F, Martins RP. 15-nW Biopotential LPFs in 0.35- μm CMOS using subthreshold-source-follower Biquads with and without gain compensation. IEEE Trans Biomed Circuits Syst 2013; 7:690-702. [PMID: 24232630 DOI: 10.1109/tbcas.2013.2238233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most biopotential readout front-ends rely on the g m- C lowpass filter (LPF) for forefront signal conditioning. A small g m realizes a large time constant ( τ = C / g m) suitable for ultra-low-cutoff filtering, saving both power and area. Yet, the noise and linearity can be compromised, given that each g m cell can involve one or several noisy and nonlinear V- I conversions originated from the active devices. This paper proposes the subthreshold-source-follower (SSF) Biquad as a prospective alternative. It features: 1) a very small number of active devices reducing the noise and nonlinearity footsteps; 2) No explicit feedback in differential implementation, and 3) extension of filter order by cascading. This paper presents an in-depth treatment of SSF Biquad in the nW-power regime, analyzing its power and area tradeoffs with gain, linearity and noise. A gain-compensation (GC) scheme addressing the gain-loss problem of NMOS-based SSF Biquad due to the body effect is also proposed. Two 100-Hz 4th-order Butterworth LPFs using the SSF Biquads with and without GC were fabricated in 0.35- μm CMOS. Measurement results show that the non-GC (GC) LPF can achieve a DC gain of -3.7 dB (0 dB), an input-referred noise of 36 μV rms (29 μV rms ), a HD3@60 Hz of -55.2 dB ( - 60.7 dB) and a die size of 0.11 mm² (0.08 mm²). Both LPFs draw 15 nW at 3 V. The achieved figure-of-merits (FoMs) are favorably comparable with the state-of-the-art.
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Irianto J, Swift J, Martins RP, McPhail GD, Knight MM, Discher DE, Lee DA. Osmotic challenge drives rapid and reversible chromatin condensation in chondrocytes. Biophys J 2013; 104:759-69. [PMID: 23442954 DOI: 10.1016/j.bpj.2013.01.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/20/2012] [Accepted: 01/07/2013] [Indexed: 02/02/2023] Open
Abstract
Changes in extracellular osmolality have been shown to alter gene expression patterns and metabolic activity of various cell types, including chondrocytes. However, mechanisms by which physiological or pathological changes in osmolality impact chondrocyte function remain unclear. Here we use quantitative image analysis, electron microscopy, and a DNase I assay to show that hyperosmotic conditions (>400 mOsm/kg) induce chromatin condensation, while hypoosmotic conditions (100 mOsm/kg) cause decondensation. Large density changes (p < 0.001) occur over a very narrow range of physiological osmolalities, which suggests that chondrocytes likely experience chromatin condensation and decondensation during a daily loading cycle. The effect of changes in osmolality on nuclear morphology (p < 0.01) and chromatin condensation (p < 0.001) also differed between chondrocytes in monolayer culture and three-dimensional agarose, suggesting a role for cell adhesion. The relationship between condensation and osmolality was accurately modeled by a polymer gel model which, along with the rapid nature of the chromatin condensation (<20 s), reveals the basic physicochemical nature of the process. Alterations in chromatin structure are expected to influence gene expression and thereby regulate chondrocyte activity in response to osmotic changes.
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Affiliation(s)
- Jerome Irianto
- Institute of Bioengineering, School of Engineering and Material Science, Queen Mary, University of London, London, United Kingdom.
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Gao J, Liu X, Chen T, Mak PI, Du Y, Vai MI, Lin B, Martins RP. An intelligent digital microfluidic system with fuzzy-enhanced feedback for multi-droplet manipulation. Lab Chip 2013; 13:443-451. [PMID: 23232546 DOI: 10.1039/c2lc41156c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The complexity of droplet hydrodynamics on a digital microfluidic (DMF) system eventually weakens its potential for application in large-scale chemical/biological micro-reactors. We describe here an intelligent DMF technology to address that intricacy. A wide variety of control-engaged droplet manageability is proposed and demonstrated through the operation of our modular DMF prototype, which comprises: (i) rigid profiling ability of different droplet's hydrodynamics under a real-time trajectory track of droplet-derived capacitance, permitting accurate and autonomous multi-droplet positioning without visual setup and heavy image signal processing; (ii) fuzzy-enhanced controllability saving up to 21% charging time when compared with the classical approach, enhancing the throughput, fidelity and lifetime of the DMF chip, while identifying and renouncing those weakened electrodes deteriorated over time, and (iii) expert manipulability of multi-droplet routings under countermeasure decisions in real time, preventing droplet-to-droplet or task-to-task interference. Altogether, this work exhibits the first modular DMF system with built-in electronic-control software-defined intelligence to enhance the fidelity and reliability of each droplet operation, allowing future manufacturability of a wide range of life science analyses and combinatorial chemical screening applications.
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Affiliation(s)
- Jie Gao
- State-Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE, University of Macau, Taipa, Macao, China
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Martins RP, Mabo P. [Epidemiology and comorbidities in atrial fibrillation]. Rev Prat 2013; 63:188-189. [PMID: 23513776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Ieong CI, Mak PI, Lam CP, Dong C, Vai MI, Mak PU, Pun SH, Wan F, Martins RP. A 0.83- μW QRS detection processor using quadratic spline wavelet transform for wireless ECG acquisition in 0.35- μm CMOS. IEEE Trans Biomed Circuits Syst 2012; 6:586-595. [PMID: 23853259 DOI: 10.1109/tbcas.2012.2188798] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Healthcare electronics count on the effectiveness of the on-patient signal preprocessing unit to moderate the wireless data transfer for better power efficiency. In order to reduce the system power in long-time ECG acquisition, this work describes an on-patient QRS detection processor for arrhythmia monitoring. It extracts the concerned ECG part, i.e., the RR-interval between the QRS complex for evaluating the heart rate variability. The processor is structured by a scale-3 quadratic spline wavelet transform followed by a maxima modulus recognition stage. The former is implemented via a symmetric FIR filter, whereas the latter includes a number of feature extraction steps: zero-crossing detection, peak (zero-derivative) detection, threshold adjustment and two finite state machines for executing the decision rules. Fabricated in 0.35-μm CMOS the 300-Hz processor draws only 0.83 μW, which is favorably comparable with the prior arts. In the system tests, the input data is placed via an on-chip 10-bit SAR analog-to-digital converter, while the output data is emitted via an off-the-shelf wireless transmitter (TI CC2500) that is configurable by the processor for different data transmission modes: 1) QRS detection result, 2) raw ECG data or 3) both. Validated with all recordings from the MIT-BIH arrhythmia database, 99.31% sensitivity and 99.70% predictivity are achieved. Mode 1 with solely the result of QRS detection exhibits 6× reduction of system power over modes 2 and 3.
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Affiliation(s)
- Chio-In Ieong
- Department of Electrical and Computer Engineering, Faculty of Science and Technology,University of Macau, Taipa, Macao 999078, China.
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Abstract
Mechanical loading induces both nuclear distortion and alterations in gene expression in a variety of cell types. Mechanotransduction is the process by which extracellular mechanical forces can activate a number of well-studied cytoplasmic signaling cascades. Inevitably, such signals are transduced to the nucleus and induce transcription factor-mediated changes in gene expression. However, gene expression also can be regulated through alterations in nuclear architecture, providing direct control of genome function. One putative transduction mechanism for this phenomenon involves alterations in nuclear architecture that result from the mechanical perturbation of the cell. This perturbation is associated with direct mechanical strain or osmotic stress, which is transferred to the nucleus. This review describes the current state of knowledge relating the nuclear architecture and the transfer of mechanical forces to the nucleus mediated by the cytoskeleton, the nucleoskeleton, and the LINC (linker of the nucleoskeleton and cytoskeleton) complex. Moreover, remodeling of the nucleus induces alterations in nuclear stiffness, which may be associated with cell differentiation. These phenomena are discussed in relation to the potential influence of nuclear architecture-mediated mechanoregulation of transcription and cell fate.
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Affiliation(s)
- Rui P Martins
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, United Kingdom
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Rosu R, Abdelaal A, Andronache M, Gusetu G, Muresan L, Martins RP, Bondor C, Pop D, Malai A, Ilea M, Pop C, Dan D, Puschita M, Nanu P, Zdrenghea D. Assessment of the correlation between two defining criteria for bidirectional isthmic block in the ablation of typical atrial flutter. Indian Pacing Electrophysiol J 2011; 10:536-46. [PMID: 21346822 PMCID: PMC3034456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND A complete, bidirectional conduction block in the cavotricuspid isthmus (CTI) represents the end-point of the typical atrial flutter ablation. We investigated the correlation between two criteria for successful ablation, one based on the atrial bipolar electrogram morphology before and after complete CTI conduction block, compared to the standard criteria of differential pacing and reversal in the right atrial depolarization sequence during coronary sinus (CS) pacing. METHOD We conducted a retrospective study in 111 patients (81 males, average age 62±10 years) who underwent an atrial flutter ablation during September 2007 - July 2009 in the Cardiology - Rehabilitation Hospital, UMF Cluj-Napoca. We assessed the presence of a bidirectional block at the end of the procedure using the standard criteria. We then analyzed the morphology of the bipolar atrial electrograms adjacent to the ablation line, before and after CTI conduction block. RESULTS A change from a qRs morphology to a rSr' morphology when pacing from the coronary sinus and from a rsr' morphology to a QRS morphology when pacing from the low-lateral right atrium was associated with a CTI conduction block. Sensitivity (Se), specificity(Sp), positive predictive value (PPV), negative predictive value (NPV) were 96%, 89%, 99% and 67% respectively. CONCLUSION Our study suggests that the analysis of the atrial bipolar electrogram next to the ablation line before and after CTI ablation may be used as a reliable criterion to validate CTI conduction block due to its high sensitivity, specificity and positive predictive value.
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Affiliation(s)
- R Rosu
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - A Abdelaal
- CHU Nancy Brabois, Department of Electrophysiology, 54500 Nancy, France
| | - M Andronache
- CHU Nancy Brabois, Department of Electrophysiology, 54500 Nancy, France
| | - G Gusetu
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - L Muresan
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - RP Martins
- CHU Nancy Brabois, Department of Electrophysiology, 54500 Nancy, France
| | - C Bondor
- UMF Cluj-Napoca, Department of Medical Data Processing and Biostatistics, 400349 Cluj-Napoca, Romania
| | - D Pop
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - A Malai
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - M Ilea
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - C Pop
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
| | - D Dan
- Baia Mare County Hospital, 430222, Baia Mare, Romania
| | - M Puschita
- Arad County Hospital, 310158 Arad, Romania
| | - P Nanu
- Arad County Hospital, 310158 Arad, Romania
| | - D Zdrenghea
- SCU Cluj-Napoca, Cardiology - Rehabilitation Hospital, 400347 Cluj-Napoca, Romania
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Zhang TT, Mak PI, Vai MI, Mak PU, Wan F, Martins RP. An ultra-low-power filtering technique for biomedical applications. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2011:1859-1862. [PMID: 22254692 DOI: 10.1109/iembs.2011.6090528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper describes an ultra-low-power filtering technique for biomedical applications designated as T-wave sensing in heart-activities detection systems. The topology is based on a source-follower-based Biquad operating in the sub-threshold region. With the intrinsic advantages of simplicity and high linearity of the source-follower, ultra-low-cutoff filtering can be achieved, simultaneously with ultra low power and good linearity. An 8(th)-order 2.4-Hz lowpass filter design example optimized in a 0.35-μm CMOS process was designed achieving over 85-dB dynamic range, 74-dB stopband attenuation and consuming only 0.36 nW at a 3-V supply.
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Affiliation(s)
- Tan-Tan Zhang
- Biomedical Engineering Laboratory, FST and State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China
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Magno AFF, Martins RP, Vaz LG, Martins LP. In vitro lingual bracket evaluation of indirect bonding with plasma arc, LED and halogen light. Orthod Craniofac Res 2010; 13:48-55. [PMID: 20078795 DOI: 10.1111/j.1601-6343.2009.01474.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Evaluate the shear bond strength (SBS) and the adhesive remnant index (ARI) of indirect bonded lingual brackets using xenon plasma arc light, light-emitting diode (LED) and conventional quartz-tungsten-halogen light. MATERIAL AND METHODS Lingual brackets were bonded indirectly to 60 premolars divided to three groups according to the curing light used: Group 1, plasma arc for 6 s; Group 2, LED for 10 s; and Group 3, halogen light for 40 s. After bonding, the specimens were subjected to a shear force until debonding. The debonding pattern was assessed and classified according to the ARI scores. The mean shear bond strengths were accessed by anova followed by the Student-Newman-Keuls test for multiple comparisons. ARI scores were assessed using the chi-square test. RESULTS The three groups showed significant differences (p < 0.001), with the averages of group 1 < group 2 < group 3. Groups showed no differences regarding ARI scores. CONCLUSION Bonding lingual brackets indirectly with plasma arc, during 60% of the time used for the LED, produced lower SBS than obtained with the latter. Using LED during 25% of the time of the halogen light produced lower SBS than obtained with the latter. These differences did not influence the debonding pattern and are clinically acceptable according to the literature.
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Affiliation(s)
- A F F Magno
- Department of Pediatric Clinic, Faculty of Dentistry of Araraquara, UNESP, Araraquara, São Paulo, Brazil.
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Baruteau AE, Leurent G, Martins RP, Thebault C, Treguer F, Leclercq C, Daubert JC, Mabo P. Peripartum cardiomyopathy in the era of cardiac magnetic resonance imaging: first results and perspectives. Int J Cardiol 2009; 144:143-5. [PMID: 19171402 DOI: 10.1016/j.ijcard.2008.12.153] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 12/14/2008] [Indexed: 12/17/2022]
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Abstract
The human protamine gene cluster consists of three tightly regulated genes, protamine 1 (PRM1), protamine 2 (PRM2) and transition protein 2 (TNP2). Their products are required to repackage the paternal genome during spermiogenesis into a functional gamete. They reside within a single DNase I-sensitive domain associated with the sperm nuclear matrix, bounded by two haploid-specific Matrix Attachment Regions. The nuclear matrix is a dynamic proteinaceous network that is associated with both transcription and replication. While substantial effort has been directed toward pre- and post-transcriptional regulation, the role of the nuclear matrix in regulating haploid expressed genes has received comparatively little attention. In this regard, the functional organization of the human PRM1 --> PRM2 --> TNP2 cluster and where appropriate, comparisons to other model systems will be considered.
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Affiliation(s)
- R P Martins
- Center for Molecular Medicine and Genetics, Institute for Scientific Computing, Wayne State University School of Medicine, 253 C.S. Mott Center, 275 East Hancock Detroit, MI 48201, USA
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Antonini Y, Costa RG, Martins RP. Floral preferences of a neotropical stingless bee, Melipona quadrifasciata Lepeletier (Apidae: Meliponina) in an urban forest fragment. BRAZ J BIOL 2006; 66:463-71. [PMID: 16862301 DOI: 10.1590/s1519-69842006000300012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 04/26/2004] [Indexed: 11/22/2022] Open
Abstract
Species of plants used by Melipona quadrifasciata Lepeletier for pollen and nectar gathering in an urban forest fragment were recorded in Belo Horizonte, Minas Gerais, Brazil. Melipona quadrifasciata visited 22 out of 103 flowering plant species. The plant species belonged mainly to Myrtaceae, Asteraceae, and Convolvulaceae (64% of the visits). Melipona quadrifasciata tended to collect pollen or nectar each time, except for Myrtaceae species, from which both pollen and nectar were collected. Bee abundance at flowers did not significantly correlate to food availability (expressed by flowering plant richness). We found a relatively high similarity (50%) between plant species used by M. quadrifasciata, which was also found in studies carried out in São Paulo State. However, low similarity (17%) was found between the results of this study and those of another done in Bahia State, Brazil.
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Affiliation(s)
- Y Antonini
- Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil.
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40
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Abstract
The typical result of a microarray experiment is a list of tens or hundreds of genes found to be differentially regulated in the condition under study. Independent of the methods used to select these genes, the common task faced by any researcher is to translate these lists of genes into a better understanding of the biological phenomena involved. Currently, this is done through a tedious combination of searches through the literature and a number of public databases. We developed Onto-Express (OE) as a novel tool able to automatically translate such lists of differentially regulated genes into functional profiles characterizing the impact of the condition studied. OE constructs functional profiles (using Gene Ontology terms) for the following categories: biochemical function, biological process, cellular role, cellular component, molecular function, and chromosome location. Statistical significance values are calculated for each category. We demonstrate the validity and the utility of this comprehensive global analysis of gene function by analyzing two breast cancer datasets from two separate laboratories. OE was able to identify correctly all biological processes postulated by the original authors, as well as discover novel relevant mechanisms.
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Affiliation(s)
- Sorin Draghici
- Department of Computer Science, Wayne State University, 5143 Cass Avenue, Detroit, MI 48202, USA.
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Abstract
The typical result of a microarray experiment is a list of tens or hundreds of genes found to be differentially regulated in the condition under study. Independent of the methods used to select these genes, the common task faced by any researcher is to translate these lists of genes into a better understanding of the biological phenomena involved. Currently, this is done through a tedious combination of searches through the literature and a number of public databases. We developed Onto-Express (OE) as a novel tool able to automatically translate such lists of differentially regulated genes into functional profiles characterizing the impact of the condition studied. OE constructs functional profiles (using Gene Ontology terms) for the following categories: biochemical function, biological process, cellular role, cellular component, molecular function, and chromosome location. Statistical significance values are calculated for each category. We demonstrate the validity and the utility of this comprehensive global analysis of gene function by analyzing two breast cancer datasets from two separate laboratories. OE was able to identify correctly all biological processes postulated by the original authors, as well as discover novel relevant mechanisms.
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Affiliation(s)
- Sorin Draghici
- Department of Computer Science, Wayne State University, 5143 Cass Avenue, Detroit, MI 48202, USA.
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Abstract
A 46,823 bp region of human chromosome 5q23.1 encompassing the seven-exon lysyl oxidase gene was characterized at the primary sequence level. Approximately 17.4% of this region is comprised of repetitive elements. The gene colocalizes with microsatellite marker D5S467. It is flanked by two candidate nuclear matrix association regions (MARs). The 5' MAR centered at position 12,500 is of the AT-rich and curved DNA class. This is followed by a large CpG island containing fifty-seven putative regulatory elements which extend from just upstream of exon 1 to intron 2. The larger 3' MAR, spans position 35,050-39,750 and is characterized by a TG-rich kinked structure that also contains a topoisomerase II binding site. Based on these results model of the transcriptional regulation of the lysy/oxidase gene is presented.
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Affiliation(s)
- R P Martins
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Abstract
The expression of each locus in our genome is regulated by a gene-potentiative mechanism, whereby the gene first assumes the necessary structural conformation to enable transcription. This serves as the corner-stone for the three-tiered regulatory mechanism of potentiation, i.e., the opening of a chromatin domain, initiation of transcription, and transcript elongation. Although this is now generally accepted as the pathway that mediates gene expression, it has never been shown directly to control the expression of any heart-related gene. Lysyl oxidase enzymatically crosslinks members of the extracellular matrix, including elastin and collagen. Formation of these structures is essential to development and tissue repair. This system has enabled us to begin to address the underlying mechanism governing the selection of connective tissue genes for expression. However, before one can dissect this mechanism, it is necessary to define and characterize the locus, i.e., the corresponding genic domain. Our progress toward creating the resources necessary to unravel this mechanism is summarized in this review.
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Affiliation(s)
- R P Martins
- Wayne State University School of Medicine, Department of Obstetrics and Gynecology, Detroit, MI 48201, USA
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Martins RP. [The state of the art in rheumatology: several historic notes]. ACTA MEDICA PORT 1989; Suppl 2:S47-55. [PMID: 2694790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Martins RP. [State of the art in rheumatology: various historical notes]. ACTA MEDICA PORT 1989; 2 Suppl 2:S47-55. [PMID: 2562636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Schreiber G, de Salles JM, Martins RP, Novaes PM. Cytogenetics of Triatominae (Hemiptera heteroptera). IV: Effect of radiations on spermatogenesis. Rev Bras Biol 1977; 37:139-45. [PMID: 322223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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