Development of lab-on-chip biosensor for the detection of toxic heavy metals: A review

A π–π Bonding-Assisted Molecular-Wiring of Folded-Cytochrome c and Naphthoquinone and Its Electron-Relay-Based Bioelectrocatalytic H2O2 Reduction Reaction Visualized by Redox-Competitive Scanning Electrochemical Microscopy

“…This is the reason why SAM and covalently functionalized approaches have been used for achieving the redox activity of organic molecules on solid electrodes. 5,21,22 Interestingly, when the above experiment was repeated on a CB-modified GCE, i.e., GCE/CB@NQ ads , a well-defined voltammetric redox signal at an apparent standard Initially, an unstable voltammetric response of up to ten cycles was observed; after that, a stable voltammetric response was noticed. The control CV response of GCE/CB@ Cytc ads is displayed in Figure 1C, curve b, showing the absence of any specific voltammetric signal.…”

“…Based on the current vs [H 2 O 2 ] plot (Figure 5B), MM kinetic parameters such as the Michaelis−Menten rate constant (K M ), the first-order catalytic rate constant for the H 2 O 2 reduction reaction (k c ), and the electron-transfer rate constant (k′ ME ) have been estimated using the following Lineweaver−Burk (LB) plot approach. 56,57 (5) wherein Γ = the surface concentration of the electroactive species (NQ) (21.3 × 10 −9 mol cm −2 ), S LB = the slope of the LB plot, and I LB = the intercept of the LB plot. Figure 5C is…”

“…For instance, a proton-coupled electron-transport reaction (electron-relay) between cytochrome c (Cytc) protein and ubiquinone (Coenzyme Q 10 ) occurs at respiratory complex-1 (cytoplasmic-membrane) of a bacterium and complex-III (cytochrome c oxidoreductase, cytochrome bc 1, or ubiquinol) of photosynthetic sites of a mitochondrial system. 1,2 Apart from that, redox-active protein/enzyme integrated bioelectrodes have enabled biosensors, 3,4 miniature lab-on-chips, 5 biomolecular electronics, 6 biofuel cells, 7,8 and device development for molecular recognition 9 etc. Indeed, owing to the insulating characteristic of the redox proteins and enzymes (redox site is shielded with a macro apoprotein unit; distance between the redox center and the outermost protein layer is far, 55�350 Å), it is a challenging task to make a direct ET (DET) between the macro-protein/enzyme unit and the underlying electrode surface.…”

Breaking the clean room barrier: exploring low-cost alternatives for microfluidic devices

“…Labs-on-a-chip (LOCs), also known as microfluidic devices, have revolutionized biomedical and chemical analysis by providing efficient, portable, and highly miniaturized solutions ( Najjar et al, 2022 ; Izadifar et al, 2023 ; Zhao et al, 2023 ). The microfluidic design of these devices enables precise control of fluid flows and processes, leading to improved accuracy and repeatability of results ( Karthik et al, 2022 ; Verma & Pandya, 2022 ). However, their high material costs and specific manufacturing processes, which need cleanroom settings, make them inaccessible to many laboratories ( Pandey et al, 2017 ; Walsh et al, 2017 ).…”

Biomolecular Piezoelectric Materials for Biosensors

“…Additionally, they refer to particular project concepts associated with the notion of a piezoelectric transducer-natural interface. The mechanical nature of piezoelectric detecting devices, for example, could cause issues in detecting the mechanical movement of a biosensor to test-taking care of microfluidics, and this reality can affect faulty sensor execution (Karthik et al, 2022).…”