A voltammetric immunosensor based on a nanoporous alumina millirod for detection of porcine serum albumin

A voltammetric immunosensor was developed for detection of porcine serum albumin (PSA) to identify raw meat products adulterated with pork. A novel strategy to fabricate multiple individual nanoporous alumina (NPA) millirods (length, 5.0 mm; diameter, 1.0 mm) as the biorecognition platform is described. Each NPA millirod was covalently bioconjugated with anti-PSA capturing antibodies (α-PSAC). Following immunocapture, the PSA bound to the α-PSAC/NPA millirod bioconjugate were tagged with gold nanoparticles (AuNPs) functionalized with anti-PSA detection antibodies as the signaling probe. Subsequently, the AuNPs were voltammetrically analyzed to quantify the target PSA. The immunosensor exhibited 100 % specificity and high sensitivity to PSA with a limit of detection (LoD) of 50 (range, 0-1000) pg/mL (R² = 0.9907). Real-world applicability was successfully validated using pork/beef adulterated mixtures with a LoD of 0.05 % (w/w). Overall, the detection performance of the proposed immunosensor was excellent and, thus, is suitable for surveillance of food safety and quality.

Utilizing Cell Culture Assisted Anodization to Fabricate Aluminium Oxide with a Gradient Microstep and Nanopore Structure

Anodic aluminum oxide (AAO) with a gradient microstep and nanopore structure (GMNP) is fabricated by inversely using cell culture to control the reaction areas in the electrochemical anodization, which shows a larger porosity than that of typical planar AAO. The figure of the microstep is influenced by the cell dehydration temperature which controls the cell shrinkage degree. A GMNP AAO with a diameter of 2.5 cm is achieved. Polymer with a gradient microstep and nanonipple structure is fabricated using the GMNP AAO as the template, which denotes that GMNP AAO could become a broad platform for the structural preparation of various materials with advanced functions.

Curvature contribution on anodic aluminium oxide pore formation: a detailed analytical study

Anodic aluminium oxide (AAO) is a self-organised nanopore that has been widely studied due to the ease of its synthesization and pore properties manipulation. However, pore growth behaviour under different geometrical surfaces is rarely studied, particularly on the effect of combined curved surfaces towards pore growth properties, which is crucial in designing unique porous platform for specific applications. This paper reports study on the decisive effect of curvature surfaces on development of pore structure and properties at a constant potential. In this work, AAO grown on treated convex and concave surfaces were analysed in terms of pore quantity, pore diameter, interpore distance, pore length and other parameters of pore bottom geometry in conjugation with observation of pore cessation, bifurcation, bending and tapering. The unique formation of tapered pore was observed and described. Major factors deciding pore properties under curved surfaces were identified and discussed. We introduced a new parameter for surface quantification known as central inscribed angle, which was identified to be the central factor which decides pore growth behaviour under a curvature. Here, we observed a different trend in growth rate of pores under different curvatures, which oppose the commonly accepted convex > planar > concave pattern. Levelling height was later identified to be the decisive factor in determining growth rate of pores under a curvature at different geometrical location. These findings open up possibility to precisely control and tailor the growing path and pore structures of AAO simply via anodising an Al sheet under combined curvature surfaces, which could be beneficial for future novel applications.

Anodization control for barrier-oxide thinning and 3D interconnected pores and direct electrodeposition of nanowire networks on native aluminium substrates

A 3D interconnecting network of AAO pores is designed to be compatible with a barrier layer thinning technique, allowing direct electrodeposition of Ni nanostructures into the pore network using the native aluminum as a substrate.