•Facile evaporation-induced self-assembly of short peptide.•Micro sized architectures consisted of well-ordered nanowires.•Aspect ratio of the nanowires are as high as 500.Amyloid β19-20 peptide (Aβ19-20), a core recognition motif of the Alzheimer's β-amyloid fiber peptide, in vitro self-assembled into architectural wires is reported. Large quantities of well-ordered wires with diameters about 200 nm spread out from nucleus. These wires have a high aspect ratio of at least 500 and a long persistence length over 100 µm. We propose that formation of the hierarchical architectures is attributed to crystal-splitting mechanism. Effective π–π stacking between the aromatic residues and antiparallel β-sheet are predominant in the wires.

•One-pot synthesis of AgNPs by ultrafast microwave-assisted method•l-Cysteine, as an ideal stabilizer, is environmentally friendly.•Monodispersed-spherical shaped AgNPs found to be around 10 nm.•This optical sensor shows high selectivity and sensitivity for Hg2 + as low as 0.01 μM.•Holds potential as a sensor for Hg2 + in ecosystems systemSilver nanoparticles (AgNPs) were successfully prepared in aqueous solution by a one-pot procedure based on a rapid microwave-assisted green approach. l-Cysteine acted as a capping agent in the process of AgNP formation. The structural and morphological characteristics of the l-cysteine-capped AgNPs were investigated by the UV–vis, CD, FL, FTIR, XRD, TEM and EDX analysis. It was found that the well-dispersed crystalline AgNPs were formed after irradiation for 90 s and had sphere-like morphology. Such strategy may facilitate new ways to the synthesis of other metal nanoparticles, such as Au, Pt and Pd. In addition, the synthesized AgNPs were developed as a platform for the detection of Hg2 + and showed a high sensitivity on the order of 1 × 10− 8 M. This sensing system could discriminate Hg2 + from a wide range of cations (Ca2 +, Ba2 +, Mn2 +, etc.). The selectivity and sensitivity of AgNPs indicated its potential use as a sensor for Hg2 + detection in the ecosystems.

1-Hydroxypyrene (1-OHP) is a ubiquitous metabolite of polycyclic aromatic hydrocarbons (PAHs) and has been widely used as a biomarker for evaluation of human exposure to PAHs. In this paper, an electrochemical sensor consisted of graphene oxide nanoribbon (GON)/octa(3-aminopropyl)octasilae quioxane octahydrochloride (OA-POSS) framework films (GON/OA-POSS) modified electrode for pre-concentrating and sensing of 1-OHP was described. The GON/OA-POSS composite films were prepared by hierarchically layer-by-layer assembly via electrostatic interactions. GON, which has higher electrical conductivity than that of graphene oxide, offers residual π-conjugated systems for adsorption of 1-OHP via π–π stacking interaction. Meanwhile, OA-POSS nanocages make the GON layers frameworked to enhance contacting between GON and 1-OHP. When 1-OHP was pre-concentrated on GON/OA-POSS frameworks modified electrode, the response signal and adsorption stability was enhanced significantly. Differential pulse voltammetry was used for direct determination of 1-OHP. The electrochemical sensor calibration curve had a range of 0.1–12.55 μM (R = 0.995) with a detection limit of 0.04 μM. The results showed that the GON/OA-POSS framework films modified electrode established a new way for simple and sensitive analysis of 1-OHP.Negatively charged graphene oxide nanoribbon (GON) and positively charged POSS octa(3-aminopropyl)octasilsequioxane octahydrochloride (OA-POSS) were employed as building blocks to layer-by-layer assemble composite framework structure (GON/OA-POSS) based on electrostatic interactions. GON allows double sided functionalization, and OA-POSS has an inner cubic rigid inorganic core offering effective interlayer space. The GON/OA-POSS framework offers residual π-conjugated domains and porosity, which makes it suitable for pre-concentrating and in situ electrochemical sensing of 1-OHP.

1-Hydroxypyrene (1-OHP) is a widely used biomarker for evaluation of polycyclic aromatic hydrocarbons (PAHs) exposure. In this paper, a 1-OHP sensor, combining pre-concentration and in situ electrochemical determination, was fabricated based on electropolymerized poly(3-methylthiophene) (P3MT). Direct electrochemical properties of 1-OHP on the P3MT modified glass carbon electrode (GCE) were investigated. A pair of well-defined reversible cyclic voltammetric peaks were observed at the P3MT/GCE with ΔEp of 30 mV. The surface coverage (Г) of 1-OHP was calculated to be 9.26 × 10−11 mol cm−2 at the P3MT/GCE and the electron transfer coefficient α was estimated to be 0.53. P3MT offers π-conjugated system to adsorb 1-OHP via π–π stacking interaction. Meanwhile, P3MT films displayed good electrocatalytic activity to the oxidation of 1-OHP. The peak currents of 1-OHP obtained by differential pulse voltammetry were linear with the concentrations of 1-OHP in a range of 0.5–20.0 μM (R = 0.9953) with a detection limit of 165 nM (S/N = 3) and a sensitivity of 12.72 μA μM−1 cm−2. The sensor also exhibited good reproducibility (with a relative standard deviation of 1.2%) and long-term stability.Graphical abstractPoly(3-methylthiophene), a kind of conductive conjugated polymer with linear π-conjugated system, was electropolymerized on glass carbon electrode. The molecules of 1-hydroxypyrene were adsorbed on the poly(3-methylthiophene) film via π–π stacking interaction and then in situ electrochemical detected by differential pulse voltammetry.Highlights► Conductive conjugated polymer as a pre-concentration material. ► Electrochemical properties of 1-hydroxypyrene were investigated. ► A sensor combines pre-concentration and in situ electrochemical detection.