Considering the significant evidential values of fingerprints in underwater criminal investigations and the need to visualise them using a user- and environmentally-friendly reagent, development of a novel, rapid and relatively greener nanobio-based reagent (NBR) is deemed beneficial. Lipase from the commercial Candida rugosa immobilised onto acid-functionalised multi-walled carbon nanotubes (NBR) was used as the safer and cheap lipid-sensing reagent to visualise groomed whole/split fingerprints on non-porous objects immersed in stagnant tap water for up to 30 days under a laboratory-controlled setting. Attenuated Total Reflectance - Fourier Transform Spectrometry, Field Emission Scanning Electron Microscopy and bioinformatics (molecular docking and molecular dynamics simulations) were employed to characterise and confirm the attachment of NBR onto the lipid constituents of wet fingerprints. Chromatographic results further confirmed the presence of n-hex-adecanoic and octadecanoic acids on fingerprints up to 30 days of immersion. Thus, NBR may potentially be useful as the future state-of-the-art fingerprint visualisation technology.

Ananas comosus (L.) Merr is one of many commercially popular fruits in the cannery food industry that contributes to the increasingly mounting agro-industrial waste. In this study, a four-factor-three-level Box-Behnken design (BBD) that comprised of sonication time (A), solvent ratio (B), amplitude (C) and liquid-solid ratio (D) for the ultrasound-assisted extraction (UAE) of pineapple peels (PP) was utilized to optimize the yield of total phenolic content (TPC). Under an optimized UAE condition [5 min; 50 % of ethanol: water; 65 % of amplitude; 35:1 mL/g of liquid-solid ratio], the highest TPC from PP of 708.10 mg gallic acid equivalent (GAE)/g DW was achieved. Antioxidant capacity analysis of PP revealed a high total flavonoid content (TFC) with the IC50 for 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) of 1146.86 +/- 11.83 mg QE/g, 11.83 mg/mL and 1578.07 +/- 25.96 mu M Fe (II)/100g, respectively. High-performance liquid chromatography (HPLC) analysis revealed that the major flavonoid in the phenolic profile of PP extracts being catechin followed by quercetin and gallic acid. The UAE of PP extracts exhibited higher TPC than known conventional extraction techniques, thus indicating its efficacy to recover satisfactory quantities of phenolics in PP under optimized conditions.