An optical fibre long period grating (LPG), modified with a coating of silica core gold shell (SiO2:Au) nanoparticles (NPs) deposited using the layer-by-layer method, was employed for the development of a biosensor. The SiO2:Au NPs were electrostatically assembled onto the LPG with the aid of a poly(allylamine hydrochloride) (PAH) polycation layer. The LPG sensor operates at the phase matching turning point to provide the highest sensitivity. The SiO2:Au NPs were modified with biotin, which was used as a ligand for streptavidin (SV) detection. The sensing mechanism is based on the measurement of the refractive index change induced by the binding of the SV to the biotin. The effect on sensitivity of increasing the surface area by virtue of the SiO2:Au nanoparticles' diameter and film thickness was studied. The lowest measured concentration of SV was 2.5nM, achieved using an LPG modified with a 3 layer (PAH/SiO2:Au) thin film composed of SiO2 NPs of 300nm diameter with a binding constant of k=1.7(pM)(-1), sensitivity of 6.9nm/ng/mm(2) and limit of detection of 19pg/mm(2).
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http://dx.doi.org/10.1016/j.bios.2015.08.046 | DOI Listing |
J Mater Chem B
January 2025
Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18200, Czech Republic.
DNA nanostructures (DNs) have gained popularity in various biomedical applications due to their unique properties, including structural programmability, ease of synthesis and functionalization, and low cytotoxicity. Effective utilization of DNs in biomedical applications requires a fundamental understanding of their interactions with living cells and the mechanics of cellular uptake. Current knowledge primarily focuses on how the physicochemical properties of DNs, such as mass, shape, size, and surface functionalization, affect uptake efficacy.
View Article and Find Full Text PDFBiophys Rev
December 2024
Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh, 201313 Noida, India.
Amyloid fibrils, historically stigmatized due to their association with diseases like Alzheimer's and Parkinson's, are now recognized as a distinct class of functional proteins with extraordinary potential. These highly ordered, cross-β-sheet protein aggregates are found across all domains of life, playing crucial physiological roles. In bacteria, functional amyloids like curli fibers are essential for surface adhesion, biofilm formation, and viral DNA packaging.
View Article and Find Full Text PDFFish Shellfish Immunol
January 2025
Jiangxi Province Key Laboratory of Synthetic Pharmaceutical Chemistry, School of Geography and Environmental Engineering, Gannan Normal University, Ganzhou, 341000, China. Electronic address:
The large-scale mining and utilization of rare earth elements have significantly increased their concentration in the environment, especially in regions surrounding mining areas. These environmentally-enriched rare earth elements accumulate in agricultural products and organisms through soil and water, potentially impacting in human health through the food chain. Erbium (Er), a rare earth element of the lanthanide series (Group IIIB), plays a crucial role in various modern technological applications.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Life Science, Sichuan Normal University, Chengdu 610066, Sichuan, China.
Inulin, a health-promoting dietary fiber, is efficiently metabolized by Weissella paramesenteroides YT175, a beneficial bacterium. The strain demonstrated a diauxic growth pattern within 48 h, reaching an optical density at 600 nm (OD) of approximately 1.5, accompanied by a significant decrease in pH to around 4.
View Article and Find Full Text PDFBiosens Bioelectron
January 2025
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China; College of Physics & Optoelectronic Engineering, Jinan University, Guangzhou, 510632, China. Electronic address:
Quantitative polymerase chain reaction (qPCR) is a well-recognized technique for amplifying and quantifying nuclear acid, and its real-time monitoring capability, ultrahigh sensitivity, and accuracy make it a "golden-standard" tool in both molecular biology research and clinical diagnostics. However, current qPCR tests rely on bulky instrumentation and skilled laboratorians in centralized laboratories, which spatially and temporally separate the sample collection and test, leading to longer sample turnaround times (TATs) and limited working conditions. Herein, we propose an integrated optical fiber real-time polymerase chain reaction (iF-PCR) system that successfully allows convenient sample collection, rapid thermocycling, closed-loop thermal annealing, and real-time fluorescence detection in a tiny capillary reactor.
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