A photonic bandgap (PBG) biosensor has been developed for the label-free detection of proteins. As the sensing in this type of structures is governed by the interaction between the evanescent field going into the cladding and the target analytes, scanning near-field optical microscopy has been used to characterize the profile of that evanescent field. The study confirms the strong exponential decrease of the signal as it goes into the cladding. This means that biorecognition events must occur as close to the PBG structure surface as possible in order to obtain the maximum sensing response. Within this context, the PBG biosensor has been biofunctionalized with half-antibodies specific to bovine serum albumin (BSA) using a UV-induced immobilization procedure. The use of half-antibodies allows one to reduce the thickness of the biorecognition volume down to ca. 2.5 nm, thus leading to a higher interaction with the evanescent field, as well as a proper orientation of their binding sites towards the target sample. Then, the biofunctionalized PBG biosensor has been used to perform a direct and real-time detection of the target BSA antigen.
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http://dx.doi.org/10.3762/bjnano.10.97 | DOI Listing |
Talanta
May 2023
Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Forensic Science Innovation and Service Center, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Excellence for Trace Analysis and Biosensor, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand; Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand. Electronic address:
Near-field communication (NFC) was used to control a portable glucose biosensor for diabetes diagnosis. The system comprised a smartphone and an NFC potentiostat connected to a screen-printed carbon electrode (SPCE) modified with Prussian blue-graphene ink and functionalized with gold nanoparticles-embedded poly (3,4ethylene dioxythiophene):polysulfonic acid coated with glucose oxidase (GOx-AuNPs-PEDOT:PSS/PB-G). GOx catalyzed the glucose redox reaction while the conductivity and sensitivity of the AuNPs-PEDOT:PSS composite enhanced electron transfer to the PB-G, which was used as a mediator.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2022
Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093.
We have developed a DNA aptamer-conjugated graphene field-effect transistor (GFET) biosensor platform to detect receptor-binding domain (RBD), nucleocapsid (N), and spike (S) proteins, as well as viral particles of original Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) coronavirus and its variants in saliva samples. The GFET biosensor is a label-free, rapid (≤20 min), ultrasensitive handheld wireless readout device. The limit of detection (LoD) and the limit of quantitation (LoQ) of the sensor are 1.
View Article and Find Full Text PDFMaterials (Basel)
June 2022
TH-PPM Group, Physics Department, Faculty of Sciences, Beni-Suef University, Beni Suef 62514, Egypt.
In this work, we have explored a novel application of one-dimensional (1D) photonic crystals (PCs) as a biomarker for the detection of organic materials in wastewater. The high concentration of organic materials may lead to adverse impact on human life. In order to save human life from these adverse effects, we have investigated the bio-alcohol sensing properties of a 1D multilayer periodic structure capable of detecting organic materials in wastewater.
View Article and Find Full Text PDFSci Rep
March 2022
Electrical Engineering Department, Faculty of Engineering, Razi University, Kermanshah, 67149-67346, Iran.
One of the most interesting topics in bio-optics is measuring the refractive index of tissues. Accordingly, two novel optical biosensor configurations for cancer cell detections have been proposed in this paper. These structures are composed of one-dimensional photonic crystal (PC) lattices coupled to two metal-insulator-metal (MIM) plasmonic waveguides.
View Article and Find Full Text PDFACS Sens
December 2020
School of Applied Chemical Engineering, Polymeric Nano Materials Laboratory, Kyungpook National University, Daegu 41566, Republic of Korea.
A wearable noninvasive biosensor for in situ urea detection and quantification was developed using a urease-immobilized photonic interpenetrating polymer network (IPN) film. The photonic IPN film was intertwined with solid-state cholesteric liquid crystals (CLC) and a poly(acrylic acid) (PAA) network on a flexible poly(ethylene terephthalate) substrate adhered to a poly(dimethylsiloxane) (PDMS) chip that was fabricated using an aluminum mold. The presence of urea in the chemical matrix of human sweat red-shifted the reflected color of the photonic IPN film, and quantification was achieved by observing the wavelength at the photonic band gap (λ) with a limit of detection of 0.
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