Simulations show that the total volatile basic amines (TVB) from spoiled fish can be sensed by aziridine-functionalized graphene nanomaterials to induce substantial changes in the physical properties.

Anthropogenic activities presently generate undesirable industrial and house waste byproducts such as heavy metallic cations (HMCs), which are then often released into the environment, despite being harmful to human beings. Developing new materials that can detect and capture HMCs is therefore highly desirable for wastewater remediation, especially if using cheap starting raw materials such as carbon. To shed theoretical light in this direction, we use density functional theory simulations to study the functionalization of pristine graphene with prototypical carbenes, RC(O)CH, with R = −OCH 3 (2a), −OH (2b), −ONa (2c), and −Ph (2d), and explore their use in sensing and capturing toxic HMCs (here, we focus on the most common and harmful ones: Cd 2+ , Hg 2+ , and Pb 2+ ). We first demonstrate that, starting from activated diazomethanes, RC(O)CHN 2 (1a−d), and graphene as precursors, it is possible to yield substituted cyclopropanes tethered to graphene, here modeled as a 6 × 6 supercell (g6×6), via a [2 + 1]cycloaddition reaction. Projected density of states and band structure calculations show that the cycloaddition reaction induces a band gap opening of the graphene, which can be used to tune it for electronic sensing devices. These nanomaterials (g6×6/3a−d) favorably interact with the metallic cations through coordination bonds with interaction energies varying from −1.18 to −2.75 eV. Differences in the electronic charge density following HMC adsorption reveal regions of electron depletion or gain induced by these interactions. Based on energetic and electronic structure analysis, we suggest that g6×6/3b−d are good candidates to detect HMCs. All the four nanomaterials show a higher affinity toward Pb 2+ , as rationalized by a synergic interaction with the graphene substrate, suggesting that they can be used for Pb 2+ sensing and removal. Notably, we demonstrate that once and only once the proper computational approach is employed, the accuracy of our predictions of a larger interaction strength of Pb 2+ with respect to Cd 2+ is validated via the agreement with available experimental data on g6×6/3b. Finally, we predict that by varying the pH, the g6×6/3b,c pair can be employed to differentially sense Cd 2+ and Hg 2+ cations.

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The development of cost-effective materials for fabricating electrodes is crucial for drug, pharmaceutical and environmental applications. This paper presents the synthesis and characterization of a novel polyketimine (PKI) membrane obtained by condensing partially of different weight percentages of oxidized polyvinyl alcohol and aminated polyether sulfone. Using the PKI membrane as a scaffold, we introduced laser-induced graphene electrodes (LIGEs) for the efficient electrochemical sensing of paracetamol (PCM), which serves as a model drug. Electrochemical measurements were conducted to assess the physico-chemical properties, including laser-induced porous graphene features, such as the heterogeneous electron transfer (HET) rate and electrochemically active surface area (ECSA). The obtained results demonstrate that the LIGEs exhibit excellent performance in PCM sensing, showing a linear detection range of 50–600 µM with a detection limit (LOD) as low as 14.3 µM and a good selectivity toward uric acid. Furthermore, the functionalization of the electrode surface with AuNPs improved the electrode physico-chemical properties (HET and ECSA) and lowered the detection limit down to 1.1 µM. Consequently, these affordable electrodes hold great potential for analysing other drugs and detecting heavy metal cations in various applications.

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In silico design by docking and molecular dynamics of short peptides that can selectively recognize IL-6 for biosensing purposes.

Point mutations are common in the human DNA genome and are closely related to higher susceptibility to cancer diseases. Therefore, suitable methods for their sensing are of general interest. In this work, we report on a magnetic electrochemical bioassay using DNA probes tethered to streptavidin magnetic beads (strep-MBs) to detect T > G single nucleotide polymorphism (SNP) within the inteleukin-6 (IL6) gene in human genomic DNA. In the presence of the target DNA fragment and tetramethylbenzidine (TMB), the electrochemical signal related to the oxidation of TMB is observed, which is much higher than the one obtained in the absence of the target. The key parameters affecting the analytical signal, such as the concentration of the biotinylated probe, its incubation time with strep-MBs, DNA hybridization time, and TMB loading, were optimized using the electrochemical signal intensity and signal-to-blank (S/B) ratio as selection criteria. Using spiked buffer solutions, the bioassay can detect the mutated allele in a wide range of concentrations (over six decades) with a low detection limit (7.3 fM). Furthermore, the bioassay displays a high specificity with high concentrations of the major allele (one mismatched), and two mismatched and non–complementary DNA. More importantly, the bioassay can detect the variation in scarcely diluted human DNA, collected from 23 donors, and can reliably distinguish between heterozygous (TG genotype) and homozygous (GG genotype) in respect to the control subjects (TT genotype), where the differences are statistically highly significant (p-value < 0.001). Thus, the bioassay is useful for cohort studies targeting one or more mutations in human DNA.