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Dey TK, Trono C, Biswas P, Giannetti A, Basumallick N, Baldini F, Bandyopadhyay S, Tombelli S. Biosensing by Polymer-Coated Etched Long-Period Fiber Gratings Working near Mode Transition and Turn-around Point. BIOSENSORS 2023; 13:731. [PMID: 37504129 PMCID: PMC10377345 DOI: 10.3390/bios13070731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023]
Abstract
A methodology to enhance the sensitivity of long-period fiber gratings (LPFGs) based on the combination of three different enhancement approaches is presented; the methods here adopted are the working near mode transition (MT) of a cladding mode (CM), working near the turn-around point of a CM and the enhancement of the evanescent field of CMs by reducing the cladding diameter or by increasing the order number of CMs. In order to combine these enhancement methodologies, an electrostatic self-assembly (ESA) process was used to deposit a polymeric overlay, with a chosen thickness, onto the etched fiber. The add-layer sensitivity of the sensor was theoretically calculated, and the demonstration of the real applicability of the developed LPFG as a biosensor was performed by means of an IgG/anti-IgG immunoassay in human serum in a thermostated microfluidic system. The limits of detection (LODs) calculated by following different procedures (three times the standard deviation of the blank and the mean value of the residuals) were 6.9 × 10-8 µg/mL and 4.5 × 10-6 µg/mL, respectively. The calculated LODs demonstrate the effectiveness of the applied methodology for sensitivity enhancement.
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Affiliation(s)
- Tanoy Kumar Dey
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India
| | - Cosimo Trono
- Istituto di Fisica Applicata "Nello Carrara", CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Palas Biswas
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India
| | - Ambra Giannetti
- Istituto di Fisica Applicata "Nello Carrara", CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Nandini Basumallick
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India
| | - Francesco Baldini
- Istituto di Fisica Applicata "Nello Carrara", CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Somnath Bandyopadhyay
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India
| | - Sara Tombelli
- Istituto di Fisica Applicata "Nello Carrara", CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
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2
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Dey TK, Tombelli S, Roy A, Biswas P, Giannetti A, Basumallick N, Baldini F, Bandyopadhyay S, Trono C. Sensitivity Analysis of Sidelobes of the Lowest Order Cladding Mode of Long Period Fiber Gratings at Turn Around Point. SENSORS (BASEL, SWITZERLAND) 2022; 22:2965. [PMID: 35458949 PMCID: PMC9028772 DOI: 10.3390/s22082965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 06/14/2023]
Abstract
A new methodology to enhance the sensitivity of a long period fiber grating sensor (LPFG) at the Turn Around Point (TAP) is here presented. The LPFG sensor has been fabricated by etching the fiber up to 20.4 µm, until the sidelobes of dispersed LP0,2 cladding mode appeared near TAP in aqueous medium. The dual peak sensitivity of the sidelobes was found to be 16,044 nm/SRIU (surrounding refractive index units) in the RI range from 1.333 to 1.3335.
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Affiliation(s)
- Tanoy Kumar Dey
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India; (T.K.D.); (A.R.); (P.B.); (N.B.)
| | - Sara Tombelli
- Institute of Applied Physics “Nello Carrara”, CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; (S.T.); (A.G.); (F.B.)
| | - Arpan Roy
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India; (T.K.D.); (A.R.); (P.B.); (N.B.)
| | - Palas Biswas
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India; (T.K.D.); (A.R.); (P.B.); (N.B.)
| | - Ambra Giannetti
- Institute of Applied Physics “Nello Carrara”, CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; (S.T.); (A.G.); (F.B.)
| | - Nandini Basumallick
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India; (T.K.D.); (A.R.); (P.B.); (N.B.)
| | - Francesco Baldini
- Institute of Applied Physics “Nello Carrara”, CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; (S.T.); (A.G.); (F.B.)
| | - Somnath Bandyopadhyay
- Central Glass and Ceramic Research Institute, CSIR-CGCRI, 196 Raja S C Mullick Road, Kolkata 700032, India; (T.K.D.); (A.R.); (P.B.); (N.B.)
| | - Cosimo Trono
- Institute of Applied Physics “Nello Carrara”, CNR-IFAC, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy; (S.T.); (A.G.); (F.B.)
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Wang R, Wu H, Qi M, Han J, Ren Z. Bovine Serum Albumin Detection by Graphene Oxide Coated Long-Period Fiber Grating. PHOTONIC SENSORS 2022; 12:220305. [PMCID: PMC8783190 DOI: 10.1007/s13320-022-0649-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/23/2021] [Indexed: 06/17/2023]
Abstract
A biosensor for bovine serum albumin (BSA) detection by graphene oxide (GO) functionalized micro-taped long-period fiber grating (GMLPG) was demonstrated. The amide bond connected between the GO and BSA enabled the BSA to attach onto the fiber surface, which changed the effective refractive index of the cladding mode and characterized the concentration of the BSA. This real-time monitoring system demonstrated a sensing sensitivity of 1.263 nm/(mg/mL) and a detection limit of 0.043 mg/mL. Moreover, it illustrated superior measurement performance of higher sensitivity in the presence of glucose and urea as the interference, which showed static sensitivities of ∼1.476 nm/(mg/mL) and 1.504 nm/(mg/mL), respectively. The proposed GMLPG demonstrated a great potential for being employed as a sensor for biomedical and biochemical applications.
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Affiliation(s)
- Ruiduo Wang
- The State Key Laboratory of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an, 710127 China
- The State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an, 710119 China
| | - Hao Wu
- The State Key Laboratory of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an, 710127 China
| | - Mei Qi
- The School of Information Science and Technology, Northwest University, Xi’an, 710127 China
| | - Jing Han
- The State Key Laboratory of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an, 710127 China
| | - Zhaoyu Ren
- The State Key Laboratory of Photoelectric Technology and Functional Materials, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi’an, 710127 China
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Lee SL, Kim J, Choi S, Han J, Seo G, Lee YW. Fiber-optic label-free biosensor for SARS-CoV-2 spike protein detection using biofunctionalized long-period fiber grating. Talanta 2021; 235:122801. [PMID: 34517659 PMCID: PMC8363218 DOI: 10.1016/j.talanta.2021.122801] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/17/2021] [Accepted: 08/11/2021] [Indexed: 11/26/2022]
Abstract
With COVID-19 widespread worldwide, people are still struggling to develop faster and more accurate diagnostic methods. Here we demonstrated the label-free detection of SARS-CoV-2 spike protein by employing a SARS-CoV-2 spike antibody-conjugated phase-shifted long-period fiber grating (PS-LPFG) inscribed with a CO2 laser. At a specific cladding mode, the wavelength separation (λD) between the two split dips of a PS-LPFG varies with the external refractive index, although it is virtually insensitive to ambient temperature variations. To detect SARS-CoV-2 spike protein, SARS-CoV-2 spike antibodies were immobilized on the fiber surface of the fabricated PS-LPFG functionalized through chemical modification. When exposed to SARS-CoV-2 spike protein with different concentrations, the antibody-immobilized PS-LPFG exhibited the variation of λD according to the protein concentration, which was caused by bioaffinity binding-induced local changes in the refractive index at its surface. In particular, we also confirmed the potential of our sensor for clinical application by detecting SARS-CoV-2 spike protein in virus transport medium. Moreover, our sensor could distinguish SARS-CoV-2 spike protein from those of MERS-CoV and offer efficient properties such as reusability and storage stability. Hence, we have successfully fabricated a promising optical transducer for the detection of SARS-CoV-2 spike protein, which can be unperturbed by external temperature disturbances.
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Affiliation(s)
- Seul-Lee Lee
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Jihoon Kim
- School of Electrical Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Sungwook Choi
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Jinsil Han
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Giwan Seo
- Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea; Research Center for Bioconvergence Analysis, Korea Basic Science Institute, Cheongju, 28119, Republic of Korea.
| | - Yong Wook Lee
- Industry 4.0 Convergence Bionics Engineering, Pukyong National University, Busan, 48513, Republic of Korea; School of Electrical Engineering, Pukyong National University, Busan, 48513, Republic of Korea.
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5
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Wen HY, Wang SF, Li CH, Yeh YT, Chiang CC. Real-Time and Sensitive Immunosensor for Label-Free Detection of Specific Antigen with a Comb of Microchannel Long-Period Fiber Grating. Anal Chem 2020; 92:15989-15996. [PMID: 33269917 DOI: 10.1021/acs.analchem.0c03519] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This study aimed to develop a comb of microchannel and immunosensor based on long-period fiber grating using the process of Lithographie Galvanoformung Abformung-like micro-electromechanical systems (LIGA-like MEMS) for real-time and label-free detection of specific antigen. The coupling between propagating core and cladding modes was conducted from the comb of microchannel long-period fiber grating (CM-LPFG). The CM-LPFG-based immunosensor consisted of a microchannel structure through photoresist stacking processes and was sandwiched with an optical fiber to obtain a long-period structure. Specific immunoglobulin against protein antigen was immobilized onto an optical fiber surface and produced a real-time resonance effect on sensing specific protein antigen from the extracted protein mixtures of the cancer cell lines. The variable transmission loss was -14.07 dB, and the resonant wavelength shift was 11.239 nm. The low limit of detection for total protein concentration was 1.363 ng/μL. Our results revealed that the CM-LPFG-based immnosensor for real-time detection of label-free protein antigen is feasible and sensitive based on the diversification of a transmission loss and achieves specific immunosensing purposes for lab-on-fiber technology.
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Affiliation(s)
- Hsin-Yi Wen
- Department of Mechanical of Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan
| | - Sheng-Feng Wang
- Department of Mechanical of Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan
| | - Chien-Hsing Li
- Department of Mechanical of Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan
| | - Yao-Tsung Yeh
- Department of Medical Laboratory Science and Biotechnology, Fooyin University, Kaohsiung 83102, Taiwan
| | - Chia-Chin Chiang
- Department of Mechanical of Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan
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Bandyopadhyay S, Shao L, Wang C, Liu S, Wu Q, Gu G, Hu J, Liu Y, Chen X, Song Z, Song X, Bao Q, Smietana M. Study on optimization of nano-coatings for ultra-sensitive biosensors based on long-period fiber grating. SENSING AND BIO-SENSING RESEARCH 2020. [DOI: 10.1016/j.sbsr.2019.100320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Bandyopadhyay S, Biswas P, Chiavaioli F, Dey TK, Basumallick N, Trono C, Giannetti A, Tombelli S, Baldini F, Bandyopadhyay S. Long-period fiber grating: a specific design for biosensing applications. APPLIED OPTICS 2017; 56:9846-9853. [PMID: 29240135 DOI: 10.1364/ao.56.009846] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/14/2017] [Indexed: 05/23/2023]
Abstract
In this paper, a detailed investigation on the modeling of long-period fiber grating (LPFG) sensors is discussed with the aim of providing a more realistic solution for their use in biosensing. Add-layer sensitivity, i.e., sensitivity of the sensor to an additional layer adhered onto the fiber surface, is quantified and a clear and complete analysis about the influence of the average thickness of the deposited biological sensing layers, as well as the change in refractive index of these layers, on the resonant wavelength of the cladding modes of an LPFG is provided. Add-layer sensitivity of LPFG sensors close to mode transition (MT) and also at turn-around point (TAP) are taken into account. Adsorbed layer thicknesses, as estimated from measured wavelength shifts of the LPFG, are found to have a good match with the values obtained through other measurement techniques.
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8
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Towards a Uniform Metrological Assessment of Grating-Based Optical Fiber Sensors: From Refractometers to Biosensors. BIOSENSORS-BASEL 2017. [PMID: 28635665 PMCID: PMC5487959 DOI: 10.3390/bios7020023] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A metrological assessment of grating-based optical fiber sensors is proposed with the aim of providing an objective evaluation of the performance of this sensor category. Attention was focused on the most common parameters, used to describe the performance of both optical refractometers and biosensors, which encompassed sensitivity, with a distinction between volume or bulk sensitivity and surface sensitivity, resolution, response time, limit of detection, specificity (or selectivity), reusability (or regenerability) and some other parameters of generic interest, such as measurement uncertainty, accuracy, precision, stability, drift, repeatability and reproducibility. Clearly, the concepts discussed here can also be applied to any resonance-based sensor, thus providing the basis for an easier and direct performance comparison of a great number of sensors published in the literature up to now. In addition, common mistakes present in the literature made for the evaluation of sensor performance are highlighted, and lastly a uniform performance assessment is discussed and provided. Finally, some design strategies will be proposed to develop a grating-based optical fiber sensing scheme with improved performance.
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9
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Quero G, Consales M, Severino R, Vaiano P, Boniello A, Sandomenico A, Ruvo M, Borriello A, Diodato L, Zuppolini S, Giordano M, Nettore IC, Mazzarella C, Colao A, Macchia PE, Santorelli F, Cutolo A, Cusano A. Long period fiber grating nano-optrode for cancer biomarker detection. Biosens Bioelectron 2016; 80:590-600. [DOI: 10.1016/j.bios.2016.02.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/27/2016] [Accepted: 02/08/2016] [Indexed: 10/22/2022]
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10
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Melo L, Burton G, Kubik P, Wild P. Long period gratings coated with hafnium oxide by plasma-enhanced atomic layer deposition for refractive index measurements. OPTICS EXPRESS 2016; 24:7654-7669. [PMID: 27137052 DOI: 10.1364/oe.24.007654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Long period gratings (LPGs) are coated with hafnium oxide using plasma-enhanced atomic layer deposition (PEALD) to increase the sensitivity of these devices to the refractive index of the surrounding medium. PEALD allows deposition at low temperatures which reduces thermal degradation of UV-written LPGs. Depositions targeting three different coating thicknesses are investigated: 30 nm, 50 nm and 70 nm. Coating thickness measurements taken by scanning electron microscopy of the optical fibers confirm deposition of uniform coatings. The performance of the coated LPGs shows that deposition of hafnium oxide on LPGs induces two-step transition behavior of the cladding modes.
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Chiavaioli F, Trono C, Giannetti A, Brenci M, Baldini F. Characterisation of a label-free biosensor based on long period grating. JOURNAL OF BIOPHOTONICS 2014; 7:312-322. [PMID: 23125124 DOI: 10.1002/jbio.201200135] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 09/11/2012] [Accepted: 10/01/2012] [Indexed: 06/01/2023]
Abstract
Optical fibre gratings, especially long period gratings, have been recently proposed as optical devices for biochemical sensing. A biochemical interaction along the grating portion induces a refractive index change and hence a change in the fiber transmission spectrum. This provides an alternative methodology with respect to other label-free optical approaches, such as surface plasmon resonance, interferometric configurations and optical resonators. The fibre biofunctionalization has been carried out by means of a novel chemistry using Eudragit L100 copolymer as opposed to the commonly used silanization procedure. Antigen-antibody interaction has been analysed by means of an IgG/anti-IgG bioassay. The biosensor was fully characterised, monitoring the kinetics during the antibody immobilization and the antigen interaction and achieving the calibration curve of the assay. A comparison of the biosensor performance was made by using two different long period gratings with distinct periods.
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12
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Śmietana M, Koba M, Mikulic P, Bock WJ. Measurements of reactive ion etching process effect using long-period fiber gratings. OPTICS EXPRESS 2014; 22:5986-5994. [PMID: 24663935 DOI: 10.1364/oe.22.005986] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The paper presents for the first time a study of long-period fiber gratings (LPFGs) applied for the measurements of reactive ion etching (RIE) process effect in various places of a plasma reactor. For the purposes of the experiment a number of highly sensitive LPFGs working at the dispersion turning point was fabricated using electric arc discharges. We show that the LPFGs allow for monitoring of the phenomena taking place in the reactor, especially those resulting in reduction of the LPFG diameter. Results of the measurements supported by simulations have shown that etching rate significantly decreases with elevation of the sample up to 3.6 mm over the electrode in the reactor, and stays constant above this height.
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Voisin V, Pilate J, Damman P, Mégret P, Caucheteur C. Highly sensitive detection of molecular interactions with plasmonic optical fiber grating sensors. Biosens Bioelectron 2014; 51:249-54. [DOI: 10.1016/j.bios.2013.07.030] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/13/2013] [Indexed: 11/30/2022]
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Zhao Y, Pang F, Dong Y, Wen J, Chen Z, Wang T. Refractive index sensitivity enhancement of optical fiber cladding mode by depositing nanofilm via ALD technology. OPTICS EXPRESS 2013; 21:26136-26143. [PMID: 24216837 DOI: 10.1364/oe.21.026136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The atomic layer deposition (ALD) technology is introduced to enhance the sensitivity of optical fiber cladding mode to surrounding refractive index (SRI) variation. The highly uniform Al2O nanofilm was deposited around the double cladding fiber (DCF) which presents cladding mode resonant feature. With the high refractive index coating, the cladding mode resonant spectrum was tuned. And the sensitivity enhancement for SRI sensor was demonstrated. Through adjusting the deposition cycles, a maximum sensitivity of 723 nm/RIU was demonstrated in the DCF with 2500 deposition cycles at the SRI of 1.34. Based on the analysis of cladding modes reorganization, the cladding modes transition of the coated DCF was investigated theoretically. With the high performance nanofilm coating, the proposed SRI sensor is expected to have wide applications in chemical sensors and biosensors.
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A protein-based biointerfacing route toward label-free immunoassays with long period gratings in transition mode. Biosens Bioelectron 2011; 31:486-91. [PMID: 22138469 DOI: 10.1016/j.bios.2011.11.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/09/2011] [Accepted: 11/10/2011] [Indexed: 11/21/2022]
Abstract
We present a fast and effective method for anchoring bioreceptors to optical waveguides exhibiting a poorly reactive polymer interface and that have to be minimally perturbed with respect to their design. The study originated from the need to biofunctionalize a fiber optic Long Period Grating (LPG) that is tuned in a highly sensitive working point, the so-called transition mode, through the deposition of a high refractive index overlay. In particular, a thin film of atactic polystyrene (PS) was dip-coated onto the LPG with a thickness suitable to optimize the LPG sensitivity to refractive index changes of the surrounding medium. Bovine serum albumin was selected as sacrificial layer for its well-known adhesion capabilities to PS surfaces, then glutaraldehyde was used to conjugate IgGs, serving as prototypical bioreceptor, on the device surface. The effectiveness of the immobilization method was assessed by studying the interaction between the immobilized IgG with a suitable anti-IgG. In a preliminary study performed by means of ELISA and surface plasmon resonance, optimal conditions for the biomolecular testing with the LPG were assessed. Four distinct interactions were thus monitored in real time following the shift of the LPG attenuation band. These experiments suggest a novel and interesting biofunctionalization approach of unreactive polymers with applications in immunosensing and basic life science research.
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16
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Li J, Sun LP, Gao S, Quan Z, Chang YL, Ran Y, Jin L, Guan BO. Ultrasensitive refractive-index sensors based on rectangular silica microfibers. OPTICS LETTERS 2011; 36:3593-3595. [PMID: 21931401 DOI: 10.1364/ol.36.003593] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We demonstrate an ultrasensitive refractive-index (RI) sensor utilizing the polarimetric interference of a rectangular silica microfiber. The measured sensitivity is as high as 18,987 nm/RIU (refractive-index unit) around the RI of 1.33, which is 1 order of magnitude higher than that of the previously reported microfiber devices. Theoretical analysis reveals that such high sensitivity not only is originated from the RI-induced birefringence variation but also relies on the unique birefringence dispersion property for the rectangular microfiber. We predict that the sensitivity can be enhanced significantly when the group birefringence approaches zero.
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Affiliation(s)
- Jie Li
- Institute of Photonics Technology, Jinan University, Guangzhou, China
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17
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Shevchenko Y, Francis TJ, Blair DAD, Walsh R, DeRosa MC, Albert J. In situ biosensing with a surface plasmon resonance fiber grating aptasensor. Anal Chem 2011; 83:7027-34. [PMID: 21815621 DOI: 10.1021/ac201641n] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Surface plasmon resonance (SPR) biosensors prepared using optical fibers can be used as a cost-effective and relatively simple-to-implement alternative to well established biosensor platforms for monitoring biomolecular interactions in situ or possibly in vivo. The fiber biosensor presented in this study utilizes an in-fiber tilted Bragg grating to excite the SPR on the surface of the sensor over a large range of external medium refractive indices, with minimal cross-sensitivity to temperature and without compromising the structural integrity of the fiber. The label-free biorecognition scheme used demonstrates that the sensor relies on the functionalization of the gold-coated fiber with aptamers, synthetic DNA sequences that bind with high specificity to a given target. In addition to monitoring the functionalization of the fiber by the aptamers in real-time, the results also show how the fiber biosensor can detect the presence of the aptamer's target, in various concentrations of thrombin in buffer and serum solutions. The findings also show how the SPR biosensor can be used to evaluate the dissociation constant (K(d)), as the binding constant agrees with values already reported in the literature.
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18
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Smietana M, Bock WJ, Mikulic P, Ng A, Chinnappan R, Zourob M. Detection of bacteria using bacteriophages as recognition elements immobilized on long-period fiber gratings. OPTICS EXPRESS 2011; 19:7971-8. [PMID: 21643046 DOI: 10.1364/oe.19.007971] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The paper presents for the first time a study of long-period gratings (LPGs) applied for label-free detection of specific bacteria using physically adsorbed bacteriophages. For the purposes of the experiment a number of highly sensitive LPGs working at the turning point of phase matching curve was fabricated in SMF28 fiber using UV exposure. We show that the device allows for real-time monitoring of phenomena taking place on the sensor's surface, including phage-bacteria interactions. For the applied conditions a resonance wavelength shift of ~1.3 nm induced by bacteria binding was observed.
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Affiliation(s)
- Mateusz Smietana
- Centre de recherche en photonique, Université du Québec en Outaouais, Gatineau, QC, Canada.
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Pilla P, Malachovská V, Borriello A, Buosciolo A, Giordano M, Ambrosio L, Cutolo A, Cusano A. Transition mode long period grating biosensor with functional multilayer coatings. OPTICS EXPRESS 2011; 19:512-526. [PMID: 21263591 DOI: 10.1364/oe.19.000512] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report our latest research results concerning the development of a platform for label-free biosensing based on overlayered Long Period Gratings (LPGs) working in transition mode. The main novelty of this work lies in a multilayer design that allows to decouple the problem of an efficient surface functionalization from that of the tuning in transition region of the cladding modes. An innovative solvent/nonsolvent strategy for the dip-coating technique was developed in order to deposit on the LPG multiple layers of transparent polymers. In particular, a primary coating of atactic polystyrene was used as high refractive index layer to tune the working point of the device in the so-called transition region. In this way, state-of-the-art-competitive sensitivity to surrounding medium refractive index changes was achieved. An extremely thin secondary functional layer of poly(methyl methacrylate-co-methacrylic acid) was deposited onto the primary coating by means of an original identification of selective solvents. This approach allowed to obtain desired functional groups (carboxyls) on the surface of the device for a stable covalent attachment of bioreceptors and minimal perturbation of the optical design. Standard 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydrosuccinimide (EDC / NHS) coupling chemistry was used to link streptavidin on the surface of the coated LPG. Highly sensitive real-time monitoring of multiple affinity assays between streptavidin and biotinylated bovine serum albumin was performed by following the shift of the LPGs attenuation bands.
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Affiliation(s)
- Pierluigi Pilla
- Optoelectonic Division, Engineering Department, University of Sannio, Benevento, Italy
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