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Synthesis of water-soluble conjugated polymer, poly(N-3-sulfopropylaniline) and the study of its glucose sensing property
摘要： A water-soluble conjugated polymer, poly(N-3-sulfopropylaniline) (PSPA) with 7–10 controlled repeating units has been synthesized through oxidative polymerization of sulfopropylaniline (SPA) monomer, which is prepared by N-alkylation of aniline using 3-propane sultone. The glass transition temperature (Tg), thermal stability, molecular weight and size distribution of the synthesized polymer were investigated by DSC, TGA and MALDI TOFF respectively. The spectral (UV-Vis, PL, NMR, FTIR) analysis has been done to develop a facile colorimetric method to sense glucose (a biomarker of diabetes). The synthesized polymers could detect glucose up to nanomolar (10?9 M), which are 106 fold less than the level of a diabetic patient (4 × 10?3-9 × 10?3 M). It is also observed that the naked eye can sense up to decimolar (10?1 M) level. The polymerization process and the chemistry of colorimetric sensing are explained through spectral and cyclic voltammetry analysis. The polymerization and the sensing of glucose occurred through the electron transfer dependent color change processes.
关键词： Polymerization,Glucose sensing,Spectroscopy,Thermal analysis
更新于2025-09-23 15:23:52
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Template Synthesis, Spectral, Thermal and Glucose Sensing of Pr3+ Complexes of Metformin Schiff-Bases
摘要： Schiff-bases of metformin with each of salicylaldehyde (HL1); 2,3-dihydroxybenzaldehyde (H2L2); 2,4-dihydroxybenzaldehyde (H2L3); 2,5-dihydroxybenzaldehyde (H2L4); 3,4-dihydroxybenzaldehyde (H2L5) and 2-hydroxynaphthaldehyde (HL6) and their complexes with Pr(III) were synthesized by template reaction. The complexes were characterized through elemental analysis, conductivity and magnetic moment measurements, IR, UV-Vis., fluorescence, GC-MS and XRD spectroscopy. The complexes exhibit a series of characteristic emission bands for Pr3+ ion in the 481-472 and 590-580 nm range with a 318-332 nm excitation source. The complexes have eight coordinated structure with the formulae [PrL1-4,6(NO3)2(H2O)3].nH2O where n = 1, 1?, 3, 4, 4 and [PrL5(NO3)(H2O)5].2H2O. The suggested stereochemistry was confirmed using TGA, DTG and DTA analysis and a mechanism for thermal decomposition was proposed. Coates-Redfern equation was used to calculate kinetic and thermodynamic parameters of the main decomposition step. The utility of the complexes towards the detection of glucose at physiologically relevant pH in phosphate buffer using UV-Vis and fluorescence spectroscopy as well as viscosity measurements are tried where the association constants were calculated.
关键词： Pr(III) complexes,Spectral and thermal properties,Glucose sensing,Metformin Schiff-bases
更新于2025-09-23 15:22:29
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Carbon nanoparticles synthesized by laser ablation of coconut shell charcoal in liquids for glucose sensing applications
摘要： In this work, Carbon Nanoparticles (CNPs) were synthesized by one step Laser ablation of natural coconut shell charcoal in ethanol and water media. The HRTEM studies showed that the average particle size was of the order of 29 nm in ethanol with amorphous nature whereas in water, the particle average size was about 15 nm with graphitic structure. Photoluminescence (PL) properties of CNPs formed were studied. CNPs coated Nickel foil electrode (NiFE) was investigated for glucose measurement by cyclic voltammetry (CV) and chronoamperometry. The CNPs exhibited good response to glucose. The sensor was stable, wide range of detection and fabricated simply without use of any kind of binder or enzymes.
关键词： coconut shell charcoal,laser ablation,glucose sensing,CNPs
更新于2025-09-19 17:13:59
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A novel optical fiber glucose biosensor based on carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film
摘要： A novel optical fiber glucose biosensor based on fluorescent carbon quantum dots (CQDs)-glucose oxidase (GOD)/cellulose acetate (CA) complex sensitive film was fabricated, in which the dip-coating method was adopted to immobilize the CQDs-GOD/CA complex sensitive film onto the end face of the optical fiber. The surface morphology, microstructure and optical performances of the sensitive film were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Zeiss Axiovert 25 inverted microscope, Fourier transform infrared spectroscopy (FTIR), Ultraviolet-visible spectrophotometer and fluorescence spectrophotometer, respectively. The developed fiber-optic biosensor exhibits high sensitivity and repeatability for continuous online detection of low concentration glucose, allowing visualization of real-time glucose fluctuations over a period of time. The change ratios in fluorescence intensity of the biosensor are linear with glucose concentration in various ranges including micromole and nanomole levels, and the relationship between relative fluorescence intensity ratio and glucose concentration complies well with the modified Stern-Volmer equation in the range of 10-200 μmol/L with the detection limit of 6.43 μM, and in the range of 10-100 nmol/L with the detection limit of 25.79 nM, respectively.
关键词： Optical fiber,Carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film,Glucose sensing,Fluorescence quenching
更新于2025-09-16 10:30:52
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Synergic effect of plasmonic gold nanoparticles and graphene oxide on the performance of glucose sensing
摘要： In this study hybrid nanostructures of Au–graphene oxide (Au–GO) were synthesized via a two-step process and used to modify the glassy carbon electrode (GCE) for electrochemical measurements of glucose. The modified electrode exhibits a fast response less than 4 s, a low detection limit of 0.025 mM and a high signal-to-noise ratio (S/N) of 3.5. The fabricated sensor shows a linear response in a large concentration range from 0.0025 mM to 15 mM with a reproducible sensitivity of 84.53 mA cm?2 mM?1, which is much higher than that of the individual Au, GO and previously reported GO/rGO based sensors. In addition, the biosensor shows excellent results for human serum which agree well with those obtained using a laboratory glucometer. Moreover, the glucose amount in selective commercially available food samples and fresh juices was also successfully measured. The biosensor exhibits excellent selectivity, thermal stability and reproducibility. The enhanced and efficient sensitivity of the developed Au–GO based biosensor may be due to the synergic effects of the plasmonic Au-nanoparticles and GO. The performance of the biosensor suggests that the reported Au–GO hybrid nanostructures can provide a novel platform for developing non-enzymatic biosensors for biomedical and industrial applications.
关键词： hybrid nanostructures,Au–graphene oxide,non-enzymatic biosensor,electrochemical measurements,glucose sensing
更新于2025-09-16 10:30:52
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<i>In vivo</i> monitoring of intracellular Ca <sup>2+</sup> dynamics in the pancreatic β-cells of zebrafish embryos
摘要： Assessing the response of pancreatic islet cells to glucose stimulation is important for understanding β-cell function. Zebrafish are a promising model for studies of metabolism in general, including stimulus-secretion coupling in the pancreas. We used transgenic zebrafish embryos expressing a genetically-encoded Ca2+ sensor in pancreatic β-cells to monitor a key step in glucose induced insulin secretion; the elevations of intracellular [Ca2+]i. In vivo and ex vivo analyses of [Ca2+]i demonstrate that β-cell responsiveness to glucose is well established in late embryogenesis and that embryonic β-cells also respond to free fatty acid and amino acid challenges. In vivo imaging of whole embryos further shows that indirect glucose administration, for example by yolk injection, results in a slow and asynchronous induction of β-cell [Ca2+]i responses, while intravenous glucose injections cause immediate and islet-wide synchronized [Ca2+]i fluctuations. Finally, we demonstrate that embryos with disrupted mutation of the CaV1.2 channel gene cacna1c are hyperglycemic and that this phenotype is associated with glucose-independent [Ca2+]i fluctuation in β-cells. The data reveal a novel central role of cacna1c in β-cell specific stimulus-secretion coupling in zebrafish and demonstrate that the novel approach we propose – to monitor the [Ca2+]i dynamics in embryonic β-cells in vivo – will help to expand the understanding of β-cell physiological functions in healthy and diseased states.
关键词： GCaMP6s,glucose-sensing of beta cells,early zebrafish development,cacna1c,in vivo imaging,Cav1.2 channel
更新于2025-09-09 09:28:46
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Glucose sensing in the presence of scattering by analyzing a partial Mueller matrix
摘要： We propose a method to analyze a partial Mueller matrix to retrieve the optical rotation and depolarization properties simultaneously for measuring glucose concentration in the presence of scattering. A Mueller matrix polarimeter using dual photoelastic modulators and rotating half wave plates that can retrieve four partial Mueller matrices (nine elements each) for a particular orientation of half wave plates has been applied for this purpose. We verify the proposed technique by measuring di?erent glucose concentrations from the normal to diabetic range in the absence and presence of scattering. A measurement precision of 0.004° in optical rotation and 0.0004 in depolarization is achieved, so that the sensitivity of detecting glucose concentration is obtained as low as 20 mg/dl for a 40 mm path length cuvette, even in the presence of scattering medium.
关键词： Mueller matrix,Glucose sensing,Polarimetry,Scattering
更新于2025-09-04 15:30:14