Nature-Inspired Biomolecular Corona Based on Poly(caffeic acid) as a Low Potential and Time-Stable Glucose Biosensor.

Herein, we present a novel biosensor based on nature-inspired poly(caffeic acid) (PCA) grafted to magnetite (Fe3O4) nanoparticles with glucose oxidase (GOx) from Aspergillus niger via adsorption technique. The biomolecular corona was applied to the fabrication of a biosensor system with a screen-printed electrode (SPE). The obtained results indicated the operation of the system at a low potential (0.1 V). Then, amperometric measurements were performed to optimize conditions like various pH and temperatures. The SPE/Fe3O4@PCA-GOx biosensor presented a linear range from 0.05 mM to 25.0 mM, with a sensitivity of 1198.0 µA mM-1 cm-2 and a limit of detection of 5.23 µM, which was compared to other biosensors presented in the literature. The proposed system was selective towards various interferents (maltose, saccharose, fructose, L-cysteine, uric acid, dopamine and ascorbic acid) and shows high recovery in relation to tests on real samples, up to 10 months of work stability. Moreover, the Fe3O4@PCA-GOx biomolecular corona has been characterized using various techniques such as Fourier transform infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Bradford assay.

Glucose determination using amperometric non-enzymatic sensor based on electroactive poly(caffeic acid)@MWCNT decorated with CuO nanoparticles.

A novel non-enzymatic glucose sensor based on poly(caffeic acid)@multi-walled carbon nanotubes decorated with CuO nanoparticles (PCA@MWCNT-CuO) was developed. The described approach involves the complexation/accumulation of Cu(II) on PCA@MWCNT followed by electrochemical CuO deposition in an alkaline electrolyte. The morphology and surface characteristics of the nanomaterial were determined by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), Raman spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS). A hybrid-support sensor device was then developed to assess the glucose concentration in different solutions. The sensitivity of the electrode is 2412 µA mM-1 cm-2. The electrode exhibited a broad linear range of 2 µM to 9 mM and a low limit of detection (LOD) of 0.43 µM (relative standard deviation, RSD = 2.3%) at + 0.45 V vs Ag/AgCl. The excellent properties obtained for glucose detection were most likely due to the synergistic effect of the combination of individual components: poly(caffeic acid), MWCNTs, and CuO. Good accuracy and high precision were demonstrated for quantifying glucose concentrations in human serum and blood samples (the recovery ranged from 95.0 to 99.5%). The GC/PCA@MWCNT-CuO sensor represents a novel, simple, and low-cost approach to the fabrication of devices for amperometric sensing of glucose.

Portable glucose biosensor based on polynorepinephrine@magnetite nanomaterial integrated with a smartphone analyzer for point-of-care application.

This work describes a novel nanoplatform based on polynorepinephrine (PNE) grafted on magnetite nanoparticles (Fe3O4) with glucose oxidase (GOx) from Aspergillus niger (Fe3O4@PNE-GOx). The system was integrated with a smartphone analyzer as a potential point-of-care testing (POCT) biosensor for glucose measurement. Covering the magnetite surface with the biomimetic polymer polynorepinephrine significantly increased the effectiveness of enzyme immobilization which was 38.40 mg g-1, compared with 17.30 mg g-1 on the bare surface of magnetite. The Fe3O4@PNE-GOx nanoplatform was deposited on a screen-printed electrode (SPE) and then used with the world's smallest ready-to-go potentiostat and a smartphone in tandem for glucose measurement. This biosensor displayed abroad range of linearity (0.2-24 mM), a low detection limit (6.1 µM), and good sensitivity (97.34 µA mM-1 cm-2). Moreover, it exhibited a fast electrocatalytic response (8 s), and long-term stability (up to 20 weeks). It was used to detect glucose in real samples such as human serum, human blood, infusion fluid, and commercial glucose solutions. The results obtained indicate that the proposed biosensor may be an attractive system for point-of-care testing (POCT), or in various industries, using asmartphone and potentiostat in tandem.

Bio-inspired magnetite/lignin/polydopamine-glucose oxidase biosensing nanoplatform. From synthesis, via sensing assays to comparison with others glucose testing techniques.

Glucose monitoring has become a crucial part of diabetes care, and is also of importance in the food industry. However, the measurements are subject to certain limitations and errors. These may result from many factors, including the strip manufacturing process, inappropriate storage, temperature, coding, aging, etc. Here, we discuss the measurement of glucose in real samples using techniques such as photometric assay, glucometers, and using a proposed biosensor. Biosensor platforms based on the multicomponent material magnetite/lignin/polydopamine-glucose oxidase with the addition of ferrocene and a dedicated carbon paste electrode (CPE/Fe3O4/Lig/PDA/GOx/Fc) were fabricated for glucose detection in real, commercially available glucose-based samples. To determine the morphological features of the materials, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM) and zeta potential measurements were carried out. Moreover, to determine the effectiveness of glucose oxidase immobilization the Bradford assays was applied. Analysis of glucose-based products was carried out based on photometric measurements using an AU480 Chemical Analyzer from Beckam Coulter, with the use of three glucometers (Wellion Calla light® WELL 900LB, CERA-CHEK 1Code®Model G400, iXell®Rev.04/10-PL), and with the use of our proposed CPE/Fe3O4/Lig/PDA/GOx/Fc biosensor. Tests on real samples demonstrated the repeatability of the results. The results showed that this biosensor has excellent potential for application in the determination of glucose in various commercial products.