Signal amplifiers: Superparamagnetic particle–antibody conjugates were used to detect a cancer biomarker in serum by surface plasmon resonance (SPR) at an unprecedented low level of 10 fg mL−1 (ca. 300 aM). Ultrahigh sensitivity is facilitated enhanced mass and refractive index from aggregates 1 μm magnetic particles on the SPR chip. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made...

A fuel cell featuring two enzymes as electrocatalysts on specially modified electrodes—an O2-tolerant hydrogenase for the anode and bilirubin oxidase cathode—produces more than 0.1 mW cm−2 (electrode) at 1 V from a non-explosive hydrogen-air (80/20) mixture. The cathode are prepared by covalently attaching respective enzymes, via 1-pyrenebutyric acid functionalities, to multiwalled carbon nanotubes pre-coated graphite. performance, which is limited reduction of O2 (4%), represents an...

• Designs of point-of-need based visual sensor detection formats are discussed. Sensor working principles, analytical challenges, and fit-for-purpose the reported approaches reviewed. Efforts to transition traditional molecular biology techniques into instrument-free sensors is outlined. Real sample analysis, pretreatment requirements, a broad range target molecules covered. Advantages simplicity, low-cost, wide usability, affordability emphasized. Emerging advancements in self-monitoring,...

Arrays suitable for genotoxicity screening are reported that generate metabolites from cytochrome P450 enzymes (CYPs) in thin-film spots. Array spots containing DNA, various human cyt P450s, and electrochemiluminescence (ECL) generating metallopolymer [Ru(bpy)2PVP10]2+ were exposed to H2O2 activate the enzymes. ECL all was visualized simultaneously using a CCD camera. Using benzo[a]pyrene as test substrate, enzyme activity producing DNA damage arrays found order CYP1B1 > CYP1A2 CYP1A1 CYP2E1...

Cytochrome (cyt) P450s comprise the enzyme superfamily responsible for human oxidative metabolism of a majority drugs and xenobiotics. Electronic delivery electrons to cyt could be used drive natural catalytic cycle fundamental investigations, stereo- regioselective synthesis, biosensors. We describe herein 30 nm nanometer-thick films on electrodes featuring excess P450 reductase (CPR) microsomes that efficiently mimic pathway first time. Redox potentials, electron-transfer rates,...

Cytochrome P450s (cyt P450s) are the major oxidative enzymes in human metabolism of drugs and xenobiotic chemicals. In nature, iron heme cyt utilize oxygen electrons delivered from NADPH by a reductase enzyme to oxidize substrates stereo- regioselectively. Significant research has been directed toward achieving these events electrochemically. This Feature Article discusses direct electrochemistry thin films utilization such for electrochemically driven biocatalysis. Maintaining confirming...

Herein we report the first serum insulin voltammetric immunosensor for diagnosis of type 1 and 2 diabetic disorders. The sensor is composed multiwalled carbon nanotube-pyrenebutyric acid frameworks on edge plane pyrolytic graphite electrodes (PGE/MWNT/Py) to which an anti-insulin antibody was covalently attached. detection picomolar levels binding surface achieved by monitoring decrease in current signals a redox probe taken electrolyte solution. This method offered limit 15 pM free present...

Platforms based on thin enzyme/DNA films were used in two-tier screening of chemicals for reactive metabolites capable producing toxicity. Microsomes the first time as sources cytochrome (cyt) P450 enzymes these devices. Initial rapid involved electrochemiluminescent (ECL) arrays featuring spots containing ruthenium poly(vinylpyridine), DNA, and rat liver microsomes or bicistronically expressed human cyt 2E1 (h2E1). Cyt activated via NADPH/reductase cycle. When bioactivation substrates gives...

In order to design a green microsomal bioreactor on suitably identified carbon electrodes, it is important understand the direct electrochemical properties at interfaces between various electrode materials and human liver microsomes (HLM). The novelty of this work investigation directly adsorbed HLM different electrodes with goal develop simple, rapid, new bioanalytical platform useful for drug metabolism inhibition assays. These novel biointerfaces are designed in study by one step...

Per the 2020 National Diabetes Statistics Report (2018 estimates), 34.2 million people of all ages (10.5% US population) had diabetes, and 88.0 Americans (34.5% adults) prediabetes (an increase from 79 in 2010). Diagnosed diabetic conditions cost nation $327 billion 2017, a 26% prior estimate $245 2012. Thus, substantial health economic burdens are placed on globally, added with ongoing COVID-19 pandemic its negative impacts pre-existing (e.g., autoimmune disorders). Our research goal is to...

An electrochemical mass sensor for clinically relevant detection of insulin in human serum conjugated to magnetic nanoparticles and captured onto antibody immobilized gold coated quartz resonators is reported the first time.

Human liver microsomes containing various drug-metabolizing cytochrome P450 (P450) enzymes, along with their NADPH-reductase bound to phospholipid membranes, were absorbed onto 1-pyrene butylamine pi–pi stacked amine-functionalized multiwalled carbon nanotube-modified graphite electrodes. The interfaced microsomal biofilm demonstrated direct electrochemical communication the underlying electrode surface and enhanced oxygen reduction electrocatalytic activity typical of heme enzymes such as...

We report for the first time voltammetric/electrochemiluminescent sensors applied to predict genotoxicity of N-nitroso compounds bioactivated by human cytochrome P450 enzymes.

Voltammetry of cytochrome P450 (cyt P450) enzymes in ultrathin films with polyions was related for the first time to electronic and secondary structure. Heterogeneous electron transfer (hET) rate constants reduction cyt P450s depended on heme iron spin state, low P450cam giving a value 40-fold larger than high human 1A2, mixed 2E1 at an intermediate value. Asymmetric reduction−oxidation peak separations increasing scan rates were explained by simulations featuring faster oxidation reduction....

Combined covalent and non-covalent functionalization of carbon nanostructures for sensitivity amplification biosensors.