纳米铂颗粒在酶生物传感器中的应用研究

采用硼氢化钠作为还原剂制备纳米铂颗粒,并分别用羧甲基纤维素(CMC)、羟丙基纤维素(HPC)、聚丙烯酸(PAA)为保护剂,提高纳米铂溶胶的稳定性。将制备的纳米铂颗粒与聚乙烯醇缩丁醛构成复合固酶膜基质,用溶胶-凝胶法固定葡萄糖氧化酶,构建葡萄糖生物传感器。实验表明,纳米铂颗粒可以大幅度提高固定化酶的催化活性。在葡萄糖浓度为10mmol／L的溶液中,响应电流从318nA／cm^2提高到13657nA／cm^2。探讨纳米颗粒效应在固定化酶中所起的作用,并分析不同条件对酶电极响应灵敏度的影响。     

Biosensor enhanced by glucose oxidase biomimetic membrane containing the platinum and silica nanoparticles

In this paper, glucose biosensor is fabricated with immobilization of glucose oxidase (GOx) in platinum and silica sol. The glucose biosensor combined with Pt and SiO₂ nanoparticles could make full use of the properties of nanoparticles. A set of experimental results indicates that the current response for the enzyme electrode containing platinum and silica nanoparticles increases from 0.32 µA cm^− 2 to 33 µA cm^− 2 in the solution of 10 mM β-D-glucose. The linear range is 3 × 10^− 5 to 3.8 × 10^− 3 M with a detection limit of 2 × 10^− 5 M at 3σ. The effects of the various volume ratios of Pt and SiO₂ sols with respect to the current response and the stability of the enzyme electrodes are studied.     

Effect of linoleic-acid modified carboxymethyl chitosan on bromelain immobilization onto self-assembled nanoparticles

Hydrogel nanoparticles could be prepared by using linoleic acid (LA) modified carboxymethyl chitosan (CMCS) after sonication. Bromelain could be loaded onto nanoparticles of LA-CMCS. Factors affecting the activity of the immobilized enzyme, including temperature, storage etc., were investigated in this study. The results showed that the stability of bromelain for heat and storage was improved after immobilization on nanoparticles. The Michaelis constant (K _m) of the immobilized enzyme was smaller than that of free enzyme, indicating that the immobilization could promote the stability of the enzyme and strengthen the affinity of the enzyme for the substrate.     

纳米颗粒对葡萄糖生物传感器性能影响的研究

制备了纳米金颗粒和纳米铜颗粒，分别用以修饰葡萄糖生物传感器，并选用丝网印刷金电极测试研究了纳米颗粒对葡萄糖生物传感器性能的影响。结果表明：纳米铜颗粒不能增强葡萄糖生物传感器的响应电流，并且延长了其响应时间；纳米金颗粒增强了葡萄糖生物传感器的响应电流，缩短了其响应时间，提高了其抗干扰性，但不能拓宽其检测的线性范围，并且响应电流受工作电压的影响较大；随着工作电压的下降，响应电流迅速下降，与未修饰葡萄糖生物传感器响应电流下降趋势一致。     

Immobilization of biomolecules on the surface of inorganic nanoparticles for biomedical applications

Abstract

Various inorganic nanoparticles have been used for drug delivery, magnetic resonance and fluorescence imaging, and cell targeting owing to their unique properties, such as large surface area and efficient contrasting effect. In this review, we focus on the surface functionalization of inorganic nanoparticles via immobilization of biomolecules and the corresponding surface interactions with biocomponents. Applications of surface-modified inorganic nanoparticles in biomedical fields are also outlined.     

A cholesterol biosensor based on gold nanoparticles decorated functionalized graphene nanoplatelets

The fabrication of a cholesterol biosensor using gold nanoparticles decorated graphene nanoplatelets has been reported. Thermally exfoliated graphene nanoplatelets act as a suitable support for the deposition of Au nanoparticles. Cholesterol biosensor electrodes have been constructed with nafion solubilized functionalized graphene nanoplatelets (f-G) as well as Au nanoparticles decorated f-G, immobilized over glassy carbon electrode. f-G and Au/f-G thin film deposited glassy carbon electrodes were further functionalized with cholesterol oxidase by physical adsorption. Au nanoparticles dispersed over f-G demonstrate the ability to substantially raise the response current. The fabricated electrodes have been tested for their electrochemical performance at a potential of 0.2 V. The fabricated Au/f-G based cholesterol biosensor exhibits sensitivity of 314 nA/μM cm² for the detection of cholesterol with a linear response up to 135 μM. Furthermore, it has been observed that the biosensor exhibits a good anti-interference ability and favorable stability over a month's period.     

Immobilization of biomolecules on the surface of inorganic nanoparticles for biomedical applications

Various inorganic nanoparticles have been used for drug delivery, magnetic resonance and fluorescence imaging, and cell targeting owing to their unique properties, such as large surface area and efficient contrasting effect. In this review, we focus on the surface functionalization of inorganic nanoparticles via immobilization of biomolecules and the corresponding surface interactions with biocomponents. Applications of surface-modified inorganic nanoparticles in biomedical fields are also outlined.     

Impedimetric biosensor based on magnetic nanoparticles for electrochemical detection of dopamine

One of the difficulties which limit the use of electrochemical sensors for detection of dopamine is the interference from ascorbic acid. We have sought to address this problem through the synthesis and characterization of a suitable electrode material based on magnetic nanoparticles. The interference from the ascorbic acid was overcome by fabricating a negatively charged electrode surface using PEGylated arginine functionalized magnetic nanoparticles (PA-MNPs). The nanoparticles were characterized by various techniques viz., X-ray diffraction, FT-Infrared spectroscopy, transmission electron microscopy and vibrating sample magnetometer. The electrochemical behavior of the proposed sensor was investigated by cyclic voltammetry and the sensor showed high sensitivity and selectivity for dopamine. The response mechanism of the modified electrode is based on the interaction between the negatively charged electrode and the positively charged dopamine. Under optimized conditions, linear calibration plots were obtained for amperometric detection of dopamine (DA) over the concentration range of 1–9 mM dopamine, with a linear correlation coefficient of 0.9836, sensitivity of 121 μA/mM and a detection limit of 7.25 μM. Electrochemical impedance spectroscopy (EIS) has been used to study the interface properties of modified electrodes. The value of the polarization resistance (R_p) increases linearly with dopamine concentration in the range of 10 μM to 1 mM and the limit of detection (LOD) was calculated to be 14.1 μM. High sensitivity and selectivity, micromolar detection limit, high reproducibility, along with ease of preparation of the electrode surface make this system suitable for the determination of DA in pharmaceutical and clinical preparations.     

Comparative study of conductometric glucose biosensor based on gold and on magnetic nanoparticles

The aim of this study was to show the feasibility and the performances of nanoparticle biosensing. A glucose conductometric biosensor was developed using two types of nanoparticles (gold and magnetic), glucose oxidase (GOD) being adsorbed on PAH (poly(allylamine hydrochloride)) modified nanoparticles, deposited on a planar interdigitated electrode (IDEs). The best sensitivities for glucose detection were obtained with magnetic nanoparticles (70 μM/mM and 3 μM of detection limit) compared to 45 μM/mM and 9 μM with gold nanoparticles and 30 μM/mM and 50 μM with GOD directly cross-linked on IDEs. When stored in phosphate buffer (20 mM, pH 7.3) at 4 °C, the biosensor showed good stability for more than 12 days.