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A Glucose Oxidase-Instructed Fluorescence Amplification Strategy for Intracellular Glucose Detection
摘要： The accurate detection of glucose in the cellular level remains a big challenge. In this study, a signal amplification strategy mediated by silver nanocube (AgNC), glucose oxidase (GOx) and silver ion fluorescence probe (denoted as AgNC-GOx/Ag+-FP) is proposed for amplified intracellular glucose detection. The AgNC is oxidized into Ag+ by H2O2 generated from the GOx-catalyzed glucose oxidation reaction, and Ag+ remarkably enhances the red fluorescence of Ag+-FP. Our results show that the AgNC-GOx/Ag+-FP is highly sensitive and specific to glucose and H2O2. Afterwards, the feasibility of using AgNC-GOx/Ag+-FP to detect intracellular glucose is verified in five different cell lines. In summary, a sensitive and specific fluorescence amplification strategy has been developed for intracellular glucose detection.
关键词： intracellular glucose,silver nanocube,fluorescence probe,glucose oxidase,signal amplification
更新于2025-11-19 16:56:35
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Functionalization of Bulk SiO2 Surface with Biomolecules for Sensing Applications: Structural and Functional Characterizations
摘要： Biomolecule immobilization on bulk silicon dioxide (SiO2) is an important aspect in the field of Si-based interfaces for biosensing. The approach used for surface preparation should guarantee not only the stable anchoring of biomolecules but also their structural integrity and biological functioning. In this paper, we review our findings on the SiO2 functionalization process to immobilize a variety of biomolecules, including glucose oxidase, horseradish peroxide, metallothionein, and DNA molecules. Morphological and chemical characterization of SiO2 surfaces after biomolecule immobilization using techniques already employed in the microelectronic industry are presented and discussed. Optical and spectrophotometric analysis revealed the preservation of biomolecules’ activity once they are anchored on the biointerface.
关键词： ssDNA,silicon,biointerface,metallothionein,TEM,horseradish peroxide,XPS,glucose oxidase
更新于2025-09-23 15:22:29
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A photoelectrochemical glucose and lactose biosensor consisting of gold nanoparticles, MnO2 and g-C3N4 decorated TiO2
摘要： In this study, an innovative light-sensitive hybrid material was used for photoelectrochemical (PEC) biosensor fabrication. Herein, gold nanoparticles modified mesoporous TiO2 was coated on an indium tin oxide substrate, after a layer of MnO2/g-C3N4 was introduced to develop a PEC biosensor that yielded a favorable electronic interface for photo-excited electron injection. Glucose oxidase and β-galactosidase were co-immobilized on the photoanode surface via silane/glutaraldehyde linkage chemistry for glucose and lactose determination. Au NPs, g-C3N4, and MnO2 were utilized to modify quintessential semiconductor TiO2 owing to their narrow band gaps, appropriate position of the valence and conduction bands, and high visible light absorption. The p–n heterojunction formation at the interface of MnO2 and g-C3N4/TiO2 was presumed, and the heterojunction facilitates the charge transport and inhibit the recombination of excited electrons. Direct electron transfer led to the hole scavenging by FADH2, which reinforced the photocurrent. The linear measurement ranges were calculated in the range of 0.004-1.75 mM, with a sensitivity of 1.54 μAmM?1cm?2 for glucose at 0 V, and 0.008-2.50 mM, with a sensitivity of 1.66 μAmM?1cm?2 for lactose at -0.4 V. To the best of our knowledge, we report the first PEC lactose biosensor, and this study opens the door to PEC multianalyte detection.
关键词： β-galactosidase,g-C3N4,Self-powered biosensor,Glucose oxidase,Gold nanoparticles
更新于2025-09-23 15:21:21
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Highly sensitive and selective sensor probe using glucose oxidase/gold nanoparticles/graphene oxide functionalized tapered optical fiber structure for detection of glucose
摘要： A tapered optical fiber structure based glucose sensor using graphene oxide (GO) and gold nanoparticles (AuNPs) is presented in this study. The waist diameter and length of the taper region are 25 μm and 6 mm, respectively. The taper region was created to expose the evanescent waves to the cladding boundaries and to get interact with the external medium. Further, the cladding of tapered region is covered with GO and AuNPs to increase the biocompatibility of sensor and to initiate the phenomenon of localized surface plasmon resonance (LSPR), respectively. The synthesized GO and AuNPs show the good absorbance properties at the peak absorbance wavelengths of 230 nm and 519 nm, respectively. The characterization of synthesized nanomaterials was done by using UV–vis spectrophotometer and TEM. The characterization of nanomaterial coated fiber probe was done by using SEM and SEM-EDS. The specificity of developed sensor probe is enhanced by immobilizing them with the glucose oxidase enzyme, that oxidized only in the presence of glucose solution. The attained results show that the developed sensor model is highly sensitive for the detection of glucose concentrations in human bodies with a sensitivity of 1.06 nm/mM in the linear range of 0 mM–11 mM with the autocorrelation accuracy of 0.9386.
关键词： Localized surface plasmon resonance,Glucose oxidase,Tapered optical fiber,Gold nanoparticles,Glucose,Graphene oxide
更新于2025-09-23 15:21:01
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Graphene quantum dot electrochemiluminescence increase by bio-generated H <sub/>2</sub> O <sub/>2</sub> and its application in direct biosensing
摘要： In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GOx) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GOx can catalytically oxidize glucose and the direct electron transfer between the redox centre of GOx and the modified electrode also has been realized, which results in the bio-generated H2O2 for increase in GQD and realizes the direct ECL ECL signal detection of glucose. The signal-increase ECL biosensor enables glucose detection with high sensitivity reaching 5 × 10?6 to 1.5 × 10?3 mol l?1 in a wide linear range from 5 × 10?6 to 1.5 × 10?3 mol l?1. Additionally, the fabrication process of such GQD-based ECL biosensor is also suitable to other biologically produced H2O2 system, suggesting the possible applications in the sensitive detection of other biologically important targets (e.g. small molecules, protein, DNA and so on).
关键词： biosensor,graphene quantum dot,direct electron transfer,glucose oxidase,glucose
更新于2025-09-19 17:13:59
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Silver nanoprisms based plasmonic ELISA for sensitive detection of fluoroquinolones
摘要： Fluoroquinolones are synthetic antibiotics that are commonly used in animal husbandry, and the consumption of animal products with fluoroquinolone residues has imposed serious threat to human health. Here, we report a plasmonic enzyme-linked immunosorbent assay (pELISA) method based on oxidative etching of silver nanoprism (AgNPR) for the quantitative and qualitative detection of danofloxacin (DAN), a fluoroquinolone antibiotic. AgNPRs that undergo colorimetric changes upon oxidative etching by H2O2 serve as the signal transducer in our design. The indirect competitive pELISA was constructed by introducing biotinylated monoclonal antibody (mAb), streptavidin and biotinylated glucose oxidase, which catalyzes the generation of H2O2 for etching AgNPRs. The quantitative detection limit of the proposed method was 0.24 ng/mL for DAN. The qualitative detection limit for DAN reached 0.32 ng/mL, which was 32-fold lower than that of the assay using 3, 3’, 5, 5’-Tetramethylbenzidine (TMB) as the signal transducer. The average recoveries of DAN in milk ranged from 103% to 121%, with a coefficient of variation of 0.6% - 3.41%. The recovery results were further confirmed using liquid chromatography-tandem mass spectrometry. In summary, the proposed AgNPR etching pELISA produces high sensitivity, good accuracy and excellent reliability for the quantitative and qualitative detection of DAN in milk.
关键词： Glucose oxidase,Quantitative and qualitative detection,Fluoroquinolones,Plasmonic ELISA,Danofloxacin,Triangular silver nanoprism
更新于2025-09-19 17:13:59
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Silver nanoparticles on graphene quantum dots as nanozyme for efficient H <sub/>2</sub> O <sub/>2</sub> reduction in a glucose biosensor
摘要： In this work, we developed graphene quantum dot-supported silver nanoparticles (AgNPs@GQDs) as Nanozyme for efficient electrocatalytic reduction of H2O2. We applied this composite material in a glucose oxidase-based glucose sensor, by drop casting a mixture of AgNPs@GQDs and chitosan (CS) on glassy carbon electrodes (GCE). Various conditions such as thickness of the AgNPs@GQDs/CS film, pH and temperatures were optimized. The proposed sensor presented excellent selectivity and sensitivity, a linear dependence on glucose concentration in the range 0.1–10 mM and a limit of detection of ca. 0.01 mM.
关键词： hydrogen peroxide reduction,electrochemical sensor,graphene quantum dots (GQDs),silver nanoparticles (AgNPs),glucose oxidase (GOx)
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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Modeling, Simulation of 3D Label Free Nano Amperometric Biosensor for Early Diagnosis of Cancerous Cells with Sustainable Interfacial Coefficients
摘要： I would like to model and simulate 3D label free Nano Amperometric Biosensor for drug delivery and detection of cancerous cells. An Amperometric biosensor is one which has a biological element and a transducer. The analysis to whom the transduction to take place is referred to as analyte. The biological element I use in my work is enzyme, it can be even a living cell, DNA and proteins. Enzyme which I use in my work is Glucose Oxidase (GODx). The analyte primitively used in experimentation is hydrogen peroxide (H2O2) and cancerous blood. The GODx reacts with H2O2 and releases out oxygen, the amount of oxygen is calibrated in terms of current in milli amperes, so the biological change is calibrated terms of electrical parameter and so it is called amperometric biosensor. But in actual practice, the process is reversible, we inhale oxygen and exhale CO2, but a biosensor releases Oxygen out and inhales the analyte decomposition. This process is called Direct Current Cyclic Voltammetry. A potentiometric biosensor calibrates the analytes in terms of potential or voltage.
关键词： Cancer,Amperometric biosensor,Biosensor,Glucose oxidase,Transducer,Interfacial coefficients
更新于2025-09-10 09:29:36