Rapid sub-micromolar amperometric enzyme biosensing with free substrate access but without nanomaterial signalling support: oxidase-based glucose detection as a proof-of-principle example

Abstract

Reported is a high-sensitivity glucose biosensor with a simple since nanomaterial-free layout of the signalling platform. Drop-dried glucose oxidase was covalently fixed to drop-dried gelatin films on Pt-electrodes, by glutaraldehyde vapor treatment.

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“…Figure S5 shows zooms of the early trial recording, with magnification of the tiny first sensor responses. For a set of nine microfluidic gelatin/GOx/Pt biosensors, prepared on nine different days and tested once, the linear response reliably showed an upper limit of about 1000 μM, while the mean response sensitivity, calculated from slope of the averaged calibration curve (Figure B), was 212 ± 44 nA μM –1 cm –2 , similar to values reported in the study that introduced gelatin-based covalent GOx immobilization . Obviously, covalent GOx fixation to gelatin is reliable and, when used for Pt WE adaptation in the our system, afforded suitable flow-based glucose biosensing.…”

Biopolymer Cooperation for Sustainable High‐Performance Oxidase‐Based Biosensing with the Simplest Possible Readout of Substrate Conversion

“…The typical linear response range of a Pt/zein/gelatin‐GOx glucose biosensor is about 1 m m , the sensitivity and practical LOD being 30–50 µA m m –1 cm –2 and about 0.5 µ m , respectively. This compared well with the performance of close equivalents that, as described in our earlier publication, [ 8 ] used an otherwise identical gelatin‐based GOx immobilization but without a zein undercoat and had a linear range of 1.8 m m , a sensitivity of about 160 µA m m –1 cm –2 and a practical LOD of 0.5 µ m . The lower sensitivity likely originates from a stronger physical hindrance of the diffusional access of the signaling H 2 O 2 to the anodically detecting electrode surface due to the additional zein coverage.…”

“…To promote simplicity and sustainability, we recently introduced an entirely nanomaterial‐free alternative architecture of fast GOx‐based glucose biosensors with sub‐μ m glucose detection capability. [ 8 ] In these the enzyme was covalently attached to an ultrathin layer of gelatin on polished Pt disk electrodes, and showed excellent signal response through its direct exposure to electrolyte, with no hindrance of substrate diffusion to the active sites. Even without any interference shielding Pt/gelatin‐GOx biosensors reported glucose in simulated serum (phosphate buffer with typical physiological concentrations of interferents) and in real serum with a recovery, relative to values from a blood glucose meter, of 103 ± 10% (mean ± SD).…”

Doble role of bathocuproine disulfonic acid as multi-walled carbon nanotubes dispersing agent and copper preconcentration ligand: Analytical applications for the development of hydrogen peroxide and glucose electrochemical sensors

“…SI (Supplementary Information) summarizes the analytical performance of the most representative electrochemical enzymatic glucose biosensors with electrochemical trasnduction reported since 2018. The detection limit of our biosensor is better than those the detection limits reported in references[23-28, 31-33] [59-64, 67-69], comparable to the ones obtained in[17- 22, 30] [53-58, 66] and higher than those reported in references[15, 16, 29, 34] [51, 52,65,70]. GCE/AuNF/GS-IL-AuNRs/GOx/GA/Naf[16] [52], Pt/GOx/gelatin [29][65] and Pt/IrNPs/Ludox/GOx [34][70] involve expensive noble metals like…”

“…The detection limit of our biosensor is better than those the detection limits reported in references[23-28, 31-33] [59-64, 67-69], comparable to the ones obtained in[17- 22, 30] [53-58, 66] and higher than those reported in references[15, 16, 29, 34] [51, 52,65,70]. GCE/AuNF/GS-IL-AuNRs/GOx/GA/Naf[16] [52], Pt/GOx/gelatin [29][65] and Pt/IrNPs/Ludox/GOx [34][70] involve expensive noble metals like…”