Direct electrophoretic microRNA preparation from clinical samples using nanofilter membrane

Electrochemical Sensor Based on Black Phosphorus for Antimony Detection Using Dip-Pen Nanolithography: The Role of Dwell Time

Heavy metals, including Sb, are major pollutants with limits on their allowed concentration in drinking water. Therefore, there is a need for sensitive, simple, and portable detection methods for which electrochemical sensors are ideally suited. In this current study, Meta-chemical surfaces are developed for electrochemical sensing by patterning gold electrode surfaces with a mixture of black phosphorus (BP) and polymethyl methacrylate (PMMA) as nanoclusters using dip-pen nanolithography. It is found that the surface-to-volume ratio (S/V), fill factor, and ink composition affect the sensitivity of the sensor for Sb detection. The S/V ratio and fill factor can be altered by the dwell time, which has a complex effect on the limit of detection (varying from 14 to 24 ppb with the changes in the dwell time). Density functional theory calculations show that the binding between Sb(III) and BP is more exergonic in the presence of PMMA. These results are significant because they allow for the development of more sensitive Sb sensors, which can affect the wider field of the detection of heavy metals in drinking water sources and achieve higher efficiency than the commonly used instruments.

Graphene-based materials and electrochemical biosensors: an overview

Graphene, an exceptional two-dimensional material, has attracted significant attention from the scientific community. Its unique physiochemical properties make it a suitable candidate for many applications in the field of biotechnology and medical sciences. High specific surface area, exceptionally high electrical conductivity, and good biocompatibility of graphene give it a large scope in disease diagnosis and biosensing applications. This review aims at presenting the advances in the journey of graphene-based materials and their successful implication as electrochemical nanobiosensors. The first part of the review summarizes the history, structure, and recent developments in the large-scale production of graphene. It further includes the sensing mechanism, the recent trends in biosensing, and improvements in graphene-based biosensors. The comparative analysis shows graphene-based electrochemical biosensors to have high sensitivity, long-term stability, and low detection limits compared to the various other biosensors.

Surface energy and stress driven growth of extremely long and high-density ZnO nanowires using a thermal step-oxidation process

Formation of highly crystalline zinc oxide (ZnO) nanowires with an extremely high aspect ratio (length = 60 μm, diameter = 50 nm) is routinely achieved by introducing an intermediate step-oxidation method during the thermal oxidation process of thin zinc (Zn) films. High-purity Zn was deposited onto clean glass substrates at room temperature using a vacuum-assisted thermal evaporation technique. Afterwards, the as-deposited Zn layers were thermally oxidized under a closed air ambient condition at different temperatures and durations. Structural, morphological, chemical, optical and electrical properties of these oxide layers were investigated using various surface characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoemission spectroscopy (XPS). It was noticed that the initial thermal oxidation of Zn films usually starts above 400 °C. Homogeneous and lateral growth of the ZnO layer is usually preferred for oxidation at a lower temperature below 500 °C. One-dimensional (1D) asymmetric growth of ZnO started to dominate thermal oxidation above 600 °C. Highly dense 1D ZnO nanowires were specifically observed after prolonged oxidation at 600 °C for 5 hours, followed by short-step oxidation at 700 °C for 30 minutes. However, direct oxidation of Zn films at 700 °C resulted in ZnO nanorod formation. The formation of ZnO nanowires using step-oxidation is explained in terms of surface free energy and compressive stress-driven Zn adatom kinetics through the grain boundaries of laterally grown ZnO seed layers. This simple thermal oxidation process using intermittent step-oxidation was found to be quite unique and very much useful to routinely grow an array of high-density ZnO nanowires. Moreover, these ZnO nanowires showed very high sensitivity and selectivity towards formaldehyde vapour sensing against few other VOCs.

One-Pot Synthesis of Nanoflower-Like Zn2SnS4 as Nanozymes for Highly Sensitive Electrochemical Detection of H2O2 Released by Living Cells

The sensitive and reliable nanozyme-based sensor enables the detection of low concentrations of H2O2 in biological microenvironments, it has potential applications as an in-situ monitoring platform for cellular H2O2 release. The uniformly dispersed bimetallic sulfide (Zn2SnS4) nanoflowers were synthesized via a one-pot hydrothermal method and the two kinds of metal ions can serve as morphology and structure directing agents for each other in the synthetic process. The nanoparticles were utilized as nanozyme materials to fabricate a novel electrochemical sensor, and it exhibits a distinct electrochemical response towards H2O2 with excellent stability and detection capability (with a minimum detection limit of 1.79 nM (S/N=3)), the excellent characteristics facilitate the precise detection of low concentrations of H2O2 in biological microenvironments. Use the macrophages differentiated from leukemia THP-1 cells as a representative sensing model, the sensor was successfully utilized for real-time monitoring of the release of H2O2 induced by living cells, which has significant potential applications in clinical diagnosis and cancer treatment.

Performance optimization of energy-efficient solar absorbers for thermal energy harvesting in modern industrial environments using a solar deep learning model

Thermal energy harvesting has seen a rise in popularity in recent years due to its potential to generate renewable energy from the sun. One of the key components of this process is the solar absorber, which is responsible for converting solar radiation into thermal energy. In this paper, a smart performance optimization of energy efficient solar absorber for thermal energy harvesting is proposed for modern industrial environments using solar deep learning model. In this model, data is collected from multiple sensors over time that measure various environmental factors such as temperature, humidity, wind speed, atmospheric pressure, and solar radiation. This data is then used to train a machine learning algorithm to make predictions on how much thermal energy can be harvested from a particular panel or system. In a computational range, the proposed solar deep learning model (SDLM) reached 83.22 % of testing and 91.72 % of training results of false positive absorption rate, 69.88 % of testing and 81.48 % of training results of false absorption discovery rate, 81.40 % of testing and 72.08 % of training results of false absorption omission rate, 75.04 % of testing and 73.19 % of training results of absorbance prevalence threshold, and 90.81 % of testing and 78.09 % of training results of critical success index. The model also incorporates components such as insulation and orientation to further improve its accuracy in predicting the amount of thermal energy that can be harvested. Solar absorbers are used in industrial environments to absorb the sun's radiation and turn it into thermal energy. This thermal energy can then be used to power things such as heating and cooling systems, air compressors, and even some types of manufacturing operations. By using a solar deep learning model, businesses can accurately predict how much thermal energy can be harvested from a particular solar absorber before making an investment in a system.

Transformation of nanoparticles via the transition of functional DNAs responsive to pH and vascular endothelial growth factor for photothermal anti-tumor therapy

This study presents a novel approach for the development of DNA-functionalized gold nanoparticles (AuNPs) capable of responding to disease-specific factors and microenvironmental changes, resulting in an effective anti-tumor effect via photothermal therapy. The AuNPs are decorated with two types of DNAs, an i-motif duplex and a VEGF split aptamer, enabling recognition of changes in pH and VEGF, respectively. The formation of VEGF aptamers on the AuNPs induces their aggregation, further enhanced by VEGF ligands. The resulting changes in the optical properties of the AuNPs are detected by monitoring the absorbance. Upon irradiation with a near-infrared laser, the aggregated AuNPs generate heat due to their thermoplasmonic characteristic, leading to an anti-tumor effect. This study demonstrates the enhanced anti-tumor effect of DNA-functionalized AuNPs via photothermal therapy in both in vitro and in vivo tumor models. These findings suggest the potential utilization of such functional AuNPs for precise disease diagnosis and treatment by detecting disease-related factors in the microenvironment.

Highly sensitive detection of malaria biomarker through matching channel and gate capacitance of integrated organic electrochemical transistors

Organic electrochemical transistors (OECTs) possess versatile advantages for biochemical and electrophysiological applications due to electrochemical gating and ion-to-electron conversion capability. Although OECTs have been successfully applied for biochemical sensing, the effect of relative capacitance for specific sensing events is still unclear. In the present work, we design integrated interdigitated OECTs (iOECTs) with on-plane gold gate and different channel geometries for point-of-care diagnosis of malaria using aptamer as receptor. The transconductance of the iOECTs gated with micro-size gold electrodes decreased with increasing the channel thicknesses, especially for devices with large channel areas, which is inconsistent with devices gated by typical Ag/AgCl electrodes, attributing to the limited gating efficiency of the micro-size gate electrode. The capacitance of gate electrode was heavily suppressed by receptors but increased with the incubation of targets. In addition, the integrated iOECTs with thin channels exhibited superior sensitivity for malaria detection with the detection limit as low as 3.2 aM, much lower than their thick channel counterpart and other state-of-the-art biosensors. These deviations could be caused by the high relative capacitances, with respect to the gate and channel capacitance (Cg/Cch), resulting in a high gate potential drop over the organic channel and thus entirely gating on the thin channel device. These findings provide guidance to optimize the geometry of OECT devices with on-chip integrated gates and the fabrication of miniaturized OECTs for biosensing applications.

Deep Learning in Mechanical Metamaterials: From Prediction and Generation to Inverse Design

Mechanical metamaterials are meticulously designed structures with exceptional mechanical properties determined by their microstructures and constituent materials. Tailoring their material and geometric distribution unlocks the potential to achieve unprecedented bulk properties and functions. However, current mechanical metamaterial design considerably relies on experienced designers' inspiration through trial and error, while investigating their mechanical properties and responses entails time-consuming mechanical testing or computationally expensive simulations. Nevertheless, recent advancements in deep learning have revolutionized the design process of mechanical metamaterials, enabling property prediction and geometry generation without prior knowledge. Furthermore, deep generative models can transform conventional forward design into inverse design. Many recent studies on the implementation of deep learning in mechanical metamaterials are highly specialized, and their pros and cons may not be immediately evident. This critical review provides a comprehensive overview of the capabilities of deep learning in property prediction, geometry generation, and inverse design of mechanical metamaterials. Additionally, this review highlights the potential of leveraging deep learning to create universally applicable datasets, intelligently designed metamaterials, and material intelligence. This article is expected to be valuable not only to researchers working on mechanical metamaterials but also those in the field of materials informatics.

Extreme Ion-Transport Inorganic 2D Membranes for Nanofluidic Applications

Inorganic 2D materials offer a new approach to controlling mass diffusion at the nanoscale. Controlling ion transport in nanofluidics is key to energy conversion, energy storage, water purification, and numerous other applications wherein persistent challenges for efficient separation must be addressed. The recent development of 2D membranes in the emerging field of energy harvesting, water desalination, and proton/Li-ion production in the context of green energy and environmental technology is herein discussed. The fundamental mechanisms, 2D membrane fabrication, and challenges toward practical applications are highlighted. Finally, the fundamental issues of thermodynamics and kinetics are outlined along with potential membrane designs that must be resolved to bridge the gap between lab-scale experiments and production levels.

Rapid on-site nucleic acid testing: On-chip sample preparation, amplification, and detection, and their integration into all-in-one systems

As nucleic acid testing is playing a vital role in increasingly many research fields, the need for rapid on-site testing methods is also increasing. The test procedure often consists of three steps: Sample preparation, amplification, and detection. This review covers recent advances in on-chip methods for each of these three steps and explains the principles underlying related methods. The sample preparation process is further divided into cell lysis and nucleic acid purification, and methods for the integration of these two steps on a single chip are discussed. Under amplification, on-chip studies based on PCR and isothermal amplification are covered. Three isothermal amplification methods reported to have good resistance to PCR inhibitors are selected for discussion due to their potential for use in direct amplification. Chip designs and novel strategies employed to achieve rapid extraction/amplification with satisfactory efficiency are discussed. Four detection methods providing rapid responses (fluorescent, optical, and electrochemical detection methods, plus lateral flow assay) are evaluated for their potential in rapid on-site detection. In the final section, we discuss strategies to improve the speed of the entire procedure and to integrate all three steps onto a single chip; we also comment on recent advances, and on obstacles to reducing the cost of chip manufacture and achieving mass production. We conclude that future trends will focus on effective nucleic acid extraction via combined methods and direct amplification via isothermal methods.

The development progress of multi-array colourimetric sensors based on the M13 bacteriophage

Techniques for detecting chemicals dispersed at low concentrations in air continue to evolve. These techniques can be applied not only to manage the quality of agricultural products using a post-ripening process but also to establish a safety prevention system by detecting harmful gases and diagnosing diseases. Recently, techniques for rapid response to various chemicals and detection in complex and noisy environments have been developed using M13 bacteriophage-based sensors. In this review, M13 bacteriophage-based multi-array colourimetric sensors for the development of an electronic nose is discussed. The self-templating process was adapted to fabricate a colour band structure consisting of an M13 bacteriophage. To detect diverse target chemicals, the colour band was utilised with wild and genetically engineered M13 bacteriophages to enhance their sensing abilities. Multi-array colourimetric sensors were optimised for application in complex and noisy environments based on simulation and deep learning analysis. The development of a multi-array colourimetric sensor platform based on the M13 bacteriophage is likely to result in significant advances in the detection of various harmful gases and the diagnosis of various diseases based on exhaled gas in the future.

Deep Learning-Assisted Droplet Digital PCR for Quantitative Detection of Human Coronavirus

Since coronavirus disease 2019 (COVID-19) pandemic rapidly spread worldwide, there is an urgent demand for accurate and suitable nucleic acid detection technology. Although the conventional threshold-based algorithms have been used for processing images of droplet digital polymerase chain reaction (ddPCR), there are still challenges from noise and irregular size of droplets. Here, we present a combined method of the mask region convolutional neural network (Mask R-CNN)-based image detection algorithm and Gaussian mixture model (GMM)-based thresholding algorithm. This novel approach significantly reduces false detection rate and achieves highly accurate prediction model in a ddPCR image processing. We demonstrated that how deep learning improved the overall performance in a ddPCR image processing. Therefore, our study could be a promising method in nucleic acid detection technology.

Recent advancements in nucleic acid detection with microfluidic chip for molecular diagnostics

The coronavirus disease 2019 (COVID-19) has extensively promoted the application of nucleic acid testing technology in the field of clinical testing. The most widely used polymerase chain reaction (PCR)-based nucleic acid testing technology has problems such as complex operation, high requirements of personnel and laboratories, and contamination. The highly miniaturized microfluidic chip provides an essential tool for integrating the complex nucleic acid detection process. Various microfluidic chips have been developed for the rapid detection of nucleic acid, such as amplification-free microfluidics in combination with clustered regularly interspaced short palindromic repeats (CRISPR). In this review, we first summarized the routine process of nucleic acid testing, including sample processing and nucleic acid detection. Then the typical microfluidic chip technologies and new research advances are summarized. We also discuss the main problems of nucleic acid detection and the future developing trend of the microfluidic chip.

High-sensitivity waveguide-integrated bolometer based on free-carrier absorption for Si photonic sensors

Conventional photon detectors necessarily face critical challenges regarding strong wavelength-selective response and narrow spectral bandwidth, which are undesirable for spectroscopic applications requiring a wide spectral range. With this perspective, herein, we overcome these challenges through a free-carrier absorption-based waveguide-integrated bolometer for infrared spectroscopic sensors on a silicon-on-insulator (SOI) platform featuring a spectrally flat response at near-infrared (NIR) range (1520-1620 nm). An in-depth thermal analysis was conducted with a systematic investigation of geometry dependence on the detectors. We achieved great performances: temperature coefficient of resistance (TCR) of -3.786%/K and sensitivity of -26.75%/mW with a low wavelength dependency, which are record-high values among reported waveguide bolometers so far, to our knowledge. In addition, a clear on-off response with the rise/fall time of 24.2/29.2 µs and a 3-dB roll-off frequency of ∼22 kHz were obtained, sufficient for a wide range of sensing applications. Together with the possibility of expanding an operation range to the mid-infrared (MIR) band, as well as simplicity in the detector architecture, our work here presents a novel strategy for integrated photodetectors covering NIR to MIR at room temperature for the development of the future silicon photonic sensors with ultrawide spectral bandwidth.

Surface-modified nanotherapeutics targeting atherosclerosis

Atherosclerosis is a chronic and metabolic-related disease that is a serious threat to human health. Currently available diagnostic and therapeutic measures for atherosclerosis lack adequate efficiency which requires promising alternative approaches. Nanotechnology-based nano-delivery systems allow for new perspectives for atherosclerosis therapy. Surface-modified nanoparticles could achieve highly effective therapeutic effects by binding to specific receptors that are abnormally overexpressed in atherosclerosis, with less adverse effects on non-target tissues. The main purpose of this review is to summarize the research progress and design ideas to target atherosclerosis using a variety of ligand-modified nanoparticle systems, discuss the shortcomings of current vector design, and look at future development directions. We hope that this review will provide novel research strategies for the design and development of nanotherapeutics targeting atherosclerosis.

Controlled growth of redox polymer network on single enzyme molecule for stable and sensitive enzyme electrode

The electrochemical applications of enzymes are often hampered by poor enzyme stability and low electron conductivity. In this work, a novel enzyme nanogel based on atom transfer radical polymerization (ATRP) has been developed for highly sensitive detection of glucose based on ferrocene (Fc) embedded in crosslinked polymer network nanogel. Enzyme surfaces are successively modified with Br initiator, and then in situ atom transfer radical polymerization (ATRP) was performed to build up crosslinked polyacrylamide network. The resulting single enzyme nanogel (ATRP-SEG) is uniform in size fairly. ATRP-SEG reveals bi-phasic inactivation, and the half-life of stable ATRP-SEG after 18-day incubation at 50 °C is 47 days, which is 197 times longer than that of free Gox (5.7 h). By introducing a ferrocene (Fc) containing redox polymer, poly(acrylamide-co-vinylferrocene), the half-life of Fc-ATRP-SEG after 18-day incubation at 50 °C is 49 days. Fc-ATRP-SEG is used for preparation of glucose-sensing electrode, and the sensitivity of Fc-ATRP-SEG electrode is 111 μA cm^-2 mM^-1, which is 366 and 1270 times higher than those of free GOx (0.303 μA cm^-2 mM^-1) and ATRP-SEG (0.0874 μA cm^-2 mM^-1), respectively. Fc-ATRP-SEG electrode maintained 90% of initial current density under 4 °C storage condition and repetitive usages every day for 7 days. Even the electrode repeatedly used in continuous harsh condition (250 rpm, room temperature), the current density maintained 96% after 12 h incubation at operational condition.

Downregulation of hsa-miR-4328 and target gene prediction in Acute Promyelocytic Leukemia

Introduction: Acute promyelocytic leukemia (APL) is defined by the PML-RARA fusion gene. APL treatment can have significant side effects, therefore the development of optimal therapeutic options is crucial. Although the study of miRNAs is still in its infancy, it has been shown that these molecules are involved in the pathogenesis of neoplasms by modulating the expression of target genes. miRNAs can be considered possible biomarkers in APL and can be used as therapeutic targets or as markers for the therapeutic response.

Objectives: The purpose of this study was to determine whether differentially expressed putative miRNAs that have RARA as a target gene could be considered reliable biomarkers for APL.

Methods: Using bioinformatics tools, a panel of 6 miRNAs with possible tropism for the RARA gene was selected from miRDB. We evaluated their expression levels in samples from patients with APL (n=20) or from healthy subjects without mutations in genes associated with leukemia or myeloproliferative diseases (n=21).

Results: All 6 putative miRNAs were identified using electrophoresis (hsamir-4299, hsa-mir-4328, hsa-mir-7851-3p, hsa-mir-6827-5p, hsa-mir-6867-5p, hsa-mir-939-5p). Of the six miRNAs, hsa-mir-4328 is deeply downregulated in subjects diagnosed with APL compared to healthy subjects, whereas hsa-mir-4299 and hsa-mir-7851-3p show small differences in expression between the two study groups, but without statistical significance. Our results suggest that hsa-mir-4328 may have a role in the pathogenesis of APL and may represent a new biomarker for this type of leukemia. Key Words: miRNA, APL, leukemia, bioinformatics.

Recent progress in nanomaterial-based bioelectronic devices for biocomputing system

Bioelectronic devices have received the massive attention because of their huge potential to develop the core electronic components for biocomputing system. Up to now, numerous bioelectronic devices have been reported such as biomemory and biologic gate by employment of biomolecules including metalloproteins and nucleic acids. However, the intrinsic limitations of biomolecules such as instability and low signal production hinder the development of novel bioelectronic devices capable of performing various novel computing functions. As a way to overcome these limitations, nanomaterials have the great potential and wide applicability to grant and extend the electronic functions, and improve the inherent properties from biomolecules. Accordingly, lots of nanomaterials including the conductive metal, graphene, and transition metal dichalcogenide nanomaterials are being used to develop the remarkable functional bioelectronic devices like the multi-bit biomemory and resistive random-access biomemory. This review discusses the nanomaterial-based superb bioelectronic devices including the biomemory, biologic gates, and bioprocessors. In conclusion, this review will provide the interdisciplinary information about utilization of various novel nanomaterials applicable for biocomputing system.

Microfluidics-based strategies for molecular diagnostics of infectious diseases

Traditional diagnostic strategies for infectious disease detection require benchtop instruments that are inappropriate for point-of-care testing (POCT). Emerging microfluidics, a highly miniaturized, automatic, and integrated technology, are a potential substitute for traditional methods in performing rapid, low-cost, accurate, and on-site diagnoses. Molecular diagnostics are widely used in microfluidic devices as the most effective approaches for pathogen detection. This review summarizes the latest advances in microfluidics-based molecular diagnostics for infectious diseases from academic perspectives and industrial outlooks. First, we introduce the typical on-chip nucleic acid processes, including sample preprocessing, amplification, and signal read-out. Then, four categories of microfluidic platforms are compared with respect to features, merits, and demerits. We further discuss application of the digital assay in absolute nucleic acid quantification. Both the classic and recent microfluidics-based commercial molecular diagnostic devices are summarized as proof of the current market status. Finally, we propose future directions for microfluidics-based infectious disease diagnosis.

Photoelastic plasmonic metasurfaces with ultra-large near infrared spectral tuning

Metasurfaces, consisting of artificially fabricated sub-wavelength meta-atoms with pre-designable electromagnetic properties, provide novel opportunities to a variety of applications such as light detectors/sensors, local field imaging and optical displays. Currently, the tuning of most metasurfaces requires redesigning and reproducing the entire structure, rendering them ineligible for post-fabrication shape-morphing or spectral reconfigurability. Here, we report a photoelastic metasurface with an all-optical and reversible resonance tuning in the near infrared range. The photoelastic metasurface consists of hexagonal gold nanoarrays deposited on a deformable substrate made of a liquid crystalline network. Upon photo-actuation, the substrate deforms, causing the lattice to change and, as a result, the plasmon resonance to shift. The centre wavelength of the plasmon resonance exhibits an ultra-large spectral tuning of over 245 nm, from 1490 to 1245 nm, while the anisotropic deformability also endows light-switchable sensitivity in probing polarization. The proposed concept establishes a light-controlled soft platform that is of great potential for tunable/reconfigurable photonic devices, such as nano-filters, -couplers, -holograms, and displays with structural colors.

On-chip miRNA extraction platforms: recent technological advances and implications for next generation point-of-care nucleic acid tests

Circulating microRNAs (or miRNAs) in bodily fluids, are increasingly being highlighted as promising diagnostic and predictive biomarkers for a broad range of pathologies. Although nucleic acid sensors have been developed that can detect minute concentrations of biomarkers with high sensitivity and sequence specificity, their robustness is often compromised by sample collection and processing prior to analysis. Such steps either (i) involve complex, multi-step procedures and toxic chemicals unsuitable for incorporation into portable devices or (ii) are inefficient and non-standardised therefore affecting the reliability/reproducibility of the test. The development of point-of-care nucleic acid tests based on the detection of miRNAs is therefore highly dependent on the development of an automated, on-chip, sample processing platform that would enable extraction or pre-purification of the biological specimen prior to reaching the sensing platform. In this review we categorise and critically discuss the most promising technologies that have been developed to facilitate the transition of nucleic acid tests based on miRNA detection from bench to bedside.

Nanoarchitectured air-stable supported lipid bilayer incorporating sucrose-bicelle complex system

Cell-membrane-mimicking supported lipid bilayers (SLBs) provide an ultrathin, self-assembled layer that forms on solid supports and can exhibit antifouling, signaling, and transport properties among various possible functions. While recent material innovations have increased the number of practically useful SLB fabrication methods, typical SLB platforms only work in aqueous environments and are prone to fluidity loss and lipid-bilayer collapse upon air exposure, which limits industrial applicability. To address this issue, herein, we developed sucrose-bicelle complex system to fabricate air-stable SLBs that were laterally mobile upon rehydration. SLBs were fabricated from bicelles in the presence of up to 40 wt% sucrose, which was verified by quartz crystal microbalance-dissipation (QCM-D) and fluorescence recovery after photobleaching (FRAP) experiments. The sucrose fraction in the system was an important factor; while 40 wt% sucrose induced lipid aggregation and defects on SLBs after the dehydration-rehydration process, 20 wt% sucrose yielded SLBs that exhibited fully recovered lateral mobility after these processes. Taken together, these findings demonstrate that sucrose-bicelle complex system can facilitate one-step fabrication of air-stable SLBs that can be useful for a wide range of biointerfacial science applications.

N/OB dative bond supplemented by N-HN/HC Hydrogen Bonds make BN-cages an attractive candidate for DNA-nucleobase adsorption – An MP2 prediction

The response of B12N12-nanocage towards DNA-nucleobases (adenine, guanine, cytosine, and thymine) is investigated using MP2 and DFT (M06-2X) levels of theory with 6-311+G** basis set. Multiple BN-cage-nucleobase structures for each...

Electrically controlled mRNA delivery using a polypyrrole-graphene oxide hybrid film to promote osteogenic differentiation of human mesenchymal stem cells

Direct messenger ribonucleic acid (mRNA) delivery to target cells or tissues has revolutionized the field of biotechnology. However, the applicability of regenerative medicine is limited by the technical difficulties of various mRNA-loaded nanocarriers. Herein, we report a new conductive hybrid film that could guide osteogenic differentiation of human adipose-derived mesenchymal stem cells (hADMSCs) via electrically controlled mRNA delivery. To find optimal electrical conductivity and mRNA-loading capacity, the polypyrrole-graphene oxide (PPy-GO) hybrid film was electropolymerized on indium tin oxide substrates. We found that the fluorescein sodium salt, a molecule partially mimicking the physical and chemical properties of mRNAs, can be effectively absorbed and released by electrical stimulation (ES). The hADMSCs cultivated on the PPy-GO hybrid film loaded with pre-osteogenic mRNAs showed the highest osteogenic differentiation under electrical stimulation. This platform can load various types of RNAs thus highly promising as a new nucleic acid delivery tool for the development of stem cell-based therapeutics.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (electrochemical and FT-IR analysis on the film, additional SEM, AFM and C-AFM images of the film, optical and fluorescence images of cells, and the primers used for RT-qPCR analysis) is available in the online version of this article at 10.1007/s12274-022-4613-y.

Simple Electric Device to Isolate Nucleic Acids from Whole Blood Optimized for Point of Care Testing of Brain Damage

BACKGROUND

Detection or monitoring of brain damage is a clinically crucial issue. Nucleic acids in the whole blood can be used as biomarkers for brain injury. Polymerase chain reaction (PCR) which is one of the most commonly used molecular diagnostic assays requires isolated nucleic acids to initiate amplification. Currently used nucleic acid isolation procedures are complicated and require laboratory equipments.

OBJECTIVE

In this study, we tried to develop a simple and convenient method to isolate nucleic acids from the whole blood sample using a tiny battery-powered electric device. The quality of the isolated nucleic acids should be suitable for PCR assay without extra preparation.

METHODS

A plastic device with separation chamber was designed and printed with a 3D printer. Two platinum electrodes were placed on both sides and a battery was used to supply the electricity. To choose the optimal nucleic acid isolation condition, diverse lysis buffers and separation buffers were evaluated, and the duration and voltage of the electricity were tested. Western blot analysis and PCR assay were used to determine the quality of the separated nucleic acids.

RESULTS

2ul of whole blood was applied to the cathode side of the separation chamber containing 78 ul of normal saline. When the electricity at 5 V was applied for 5 min, nucleic acids were separated from segment 1 to 3 of the separation chamber. The concentration of nucleic acids peaked around 7~8 mm from cathode side. PCR assay using the separation buffer as the template was performed successfully both in conventional and realtime PCR methods. The hemoglobin in the whole blood did not show the inhibitory effect in our separation system and it may be due to structural modification of hemoglobin during electric separation.

CONCLUSION

Our simple electric device can separate nucleic acids from the whole blood sample by applying electricity at 5 V for 5 min. The separation buffer solution taken from the device can be used for PCR assay successfully.

Additively manufactured nano-mechanical energy harvesting systems: advancements, potential applications, challenges and future perspectives

Additively manufactured nano-MEH systems are widely used to harvest energy from renewable and sustainable energy sources such as wind, ocean, sunlight, raindrops, and ambient vibrations. A comprehensive study focusing on in-depth technology evolution, applications, problems, and future trends of specifically 3D printed nano-MEH systems with an energy point of view is rarely conducted. Therefore, this paper looks into the state-of-the-art technologies, energy harvesting sources/methods, performance, implementations, emerging applications, potential challenges, and future perspectives of additively manufactured nano-mechanical energy harvesting (3DP-NMEH) systems. The prevailing challenges concerning renewable energy harvesting capacities, optimal energy scavenging, power management, material functionalization, sustainable prototyping strategies, new materials, commercialization, and hybridization are discussed. A novel solution is proposed for renewable energy generation and medicinal purposes based on the sustainable utilization of recyclable municipal and medical waste generated during the COVID-19 pandemic. Finally, recommendations for future research are presented concerning the cutting-edge issues hurdling the optimal exploitation of renewable energy resources through NMEHs. China and the USA are the most significant leading forces in enhancing 3DP-NMEH technology, with more than 75% contributions collectively. The reported output energy capacities of additively manufactured nano-MEH systems were 0.5-32 mW, 0.0002-45.6 mW, and 0.3-4.67 mW for electromagnetic, piezoelectric, and triboelectric nanogenerators, respectively. The optimal strategies and techniques to enhance these energy capacities are compiled in this paper.

Effect of biochemical and biomechanical factors on vascularization of kidney organoid-on-a-chip

Kidney organoids derived from the human pluripotent stem cells (hPSCs) recapitulating human kidney are the attractive tool for kidney regeneration, disease modeling, and drug screening. However, the kidney organoids cultured by static conditions have the limited vascular networks and immature nephron-like structures unlike human kidney. Here, we developed a kidney organoid-on-a-chip system providing fluidic flow mimicking shear stress with optimized extracellular matrix (ECM) conditions. We demonstrated that the kidney organoids cultured in our microfluidic system showed more matured podocytes and vascular structures as compared to the static culture condition. Additionally, the kidney organoids cultured in microfluidic systems showed higher sensitivity to nephrotoxic drugs as compared with those cultured in static conditions. We also demonstrated that the physiological flow played an important role in maintaining a number of physiological functions of kidney organoids. Therefore, our kidney organoid-on-a-chip system could provide an organoid culture platform for in vitro vascularization in formation of functional three-dimensional (3D) tissues.

Discrimination and isolation of the virus from free RNA fragments for the highly sensitive measurement of SARS-CoV-2 abundance on surfaces using a graphene oxide nano surface

It is highly important to sensitively measure the abundance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on various surfaces. Here, we present a nucleic acid-based detection method consisting of a new sample preparation protocol that isolates only viruses, not the free RNA fragments already present on the surfaces of indoor human-inhabited environments, using a graphene oxide-coated microbead filter. Wet wipes (100 cm2), not cotton swabs, were used to collect viruses from environmental surfaces with large areas, and viruses were concentrated and separated with a graphene oxide-coated microbead filter. Viral RNA from virus was recovered 88.10 ± 8.03% from the surface and free RNA fragment was removed by 99.75 ± 0.19% from the final eluted solution. When we tested the developed method under laboratory conditions, a 10-fold higher viral detection sensitivity (Detection limit: 1 pfu/100 cm2) than the current commercial protocol was observed. Using our new sample preparation protocol, we also confirmed that the virus was effectively removed from surfaces after chemical disinfection; we were unable to measure the disinfection efficiency using the current commercial protocol because it cannot distinguish between viral RNA and free RNA fragments. Finally, we investigated the presence of SARS-CoV-2 and bacteria in 12 individual negative pressure wards in which patients with SARS-CoV-2 infection had been hospitalized. Bacteria (based on 16 S DNA) were found in all samples collected from patient rooms; however, SARS-CoV-2 was mainly detected in rooms shared by two patients.

Recent Advances in Fabrication of Flexible, Thermochromic Vanadium Dioxide Films for Smart Windows

Monoclinic-phase VO₂ (VO₂(M)) has been extensively studied for use in energy-saving smart windows owing to its reversible insulator–metal transition property. At the critical temperature (T_c = 68 °C), the insulating VO₂(M) (space group P21/c) is transformed into metallic rutile VO₂ (VO₂(R) space group P42/mnm). VO₂(M) exhibits high transmittance in the near-infrared (NIR) wavelength; however, the NIR transmittance decreases significantly after phase transition into VO₂(R) at a higher T_c, which obstructs the infrared radiation in the solar spectrum and aids in managing the indoor temperature without requiring an external power supply. Recently, the fabrication of flexible thermochromic VO₂(M) thin films has also attracted considerable attention. These flexible films exhibit considerable potential for practical applications because they can be promptly applied to windows in existing buildings and easily integrated into curved surfaces, such as windshields and other automotive windows. Furthermore, flexible VO₂(M) thin films fabricated on microscales are potentially applicable in optical actuators and switches. However, most of the existing fabrication methods of phase-pure VO₂(M) thin films involve chamber-based deposition, which typically require a high-temperature deposition or calcination process. In this case, flexible polymer substrates cannot be used owing to the low-thermal-resistance condition in the process, which limits the utilization of flexible smart windows in several emerging applications. In this review, we focus on recent advances in the fabrication methods of flexible thermochromic VO₂(M) thin films using vacuum deposition methods and solution-based processes and discuss the optical properties of these flexible VO₂(M) thin films for potential applications in energy-saving smart windows and several other emerging technologies.

Impact of the conjugation of antibodies to the surfaces of polymer nanoparticles on the immune cell targeting abilities

Antibodies have been widely used to provide targeting ability and to enhance bioactivity owing to their high specificity, availability, and diversity. Recent advances in biotechnology and nanotechnology permit site-specific engineering of antibodies and their conjugation to the surfaces of nanoparticles (NPs) in various orientations through chemical conjugations and physical adhesions. This study proposes the conjugation of poly(lactic-co-glycolic acid) (PLGA) NPs with antibodies by using two distinct methods, followed by a comparison between the cell-targeting efficiencies of both techniques. Full-length antibodies were conjugated to the PLGA-poly(ethylene glycol)-carboxylic acid (PLGA-PEG-COOH) NPs through the conventional carbodiimide coupling reaction, and f(ab')2 antibody fragments were conjugated to the PLGA-poly(ethylene glycol)-maleimide(PLGA-PEG-Mal) NPs through interactions between the f(ab')2 fragment thiol groups and the maleimide located on the nanoparticle surface. The results demonstrate that the PLGA nanoparticles conjugated with the f(ab')2 antibody fragments had a higher targeting efficiency in vitro and in vivo than that of the PLGA nanoparticles conjugated with the full-length antibodies. The results of this study can be built upon to design a delivery technique for drugs through biocompatible nanoparticles.

Ag2S quantum dot theragnostics

Silver sulfide quantum dots (Ag₂S QDs) as a theragnostic agent have received much attention because they provide excellent optical and chemical properties to facilitate diagnosis and therapy simultaneously.