A key aspect of biochip and biosensor preparation is optimization of the optical or electrochemical techniques that combine high sensitivity and specificity. Among them, optical techniques such as the use of fluorescent polymeric nanoparticles have resulted in dramatic progress in the field of diagnostics due to their range of advantages. We herein report a facile approach for the development of novel fluorescein polymeric nanoparticles (FPNPs) with immobilization of specific biomolecules for application in a highly sensitive optical biosensor. A series of three amphiphilic fluorescein polymers (poly(FMA-r-NAS-r-MA)), comprising hydrophobic fluorescein O-methacrylate (FMA), hydrophilic N-acryloxysuccinimide (NAS), and methacrylic acid (MA) monomers were synthesized through radical polymerization. In an aqueous environment, these fluorescein polymers self-assembled into spherical shaped nanoparticles with a well-defined particle size, narrow particle size distribution, and enhanced fluorescence properties. The bio-immobilization properties of the FPNPs were also tunable by control of the activated N-hydroxysuccinimide ester group in the polymer series. Furthermore, the fluorescence sensitivity of bovine serum albumin detection by the FPNPs indicates that the limit of detection and sensitivity were improved compared to conventional fluorescence dye-labelled proteins. These novel FPNPs therefore represent a suitable technology for disease diagnosis and biomarker detection to ultimately improve the sensitivity of existing analytical methodologies in a facile and cost-effective manner.

Suppression of pathogenic bacterial growth to increase food and agricultural productivity is important. We previously developed novel hexapeptides (KCM12 and KCM21) with antimicrobial activities against various phytopathogenic bacteria and N₂ plasma-treated buffer (NPB) as an alternative method for bacterial inactivation and as an antibiofilm agent of crops. Here, we developed an enhanced antibiofilm method based on antimicrobial hexapeptides with N₂ plasma-treated buffer against plant pathogens. Our results demonstrated that hexapeptides effectively inhibited the growth of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and the biofilm it formed. Potent biofilm formation-inhibiting effects of hexapeptides were observed at concentrations of above 20 µM, and samples treated with hexapeptide above 100 µM reduced the ability of the bacteria to produce biofilm by 80%. 3D confocal laser scanning microscopy imaging data revealed that the antimicrobial activity of hexapeptides was enough to affect the cells embedded inside the biofilm. Finally, combination treatment with NPB and antimicrobial hexapeptides increased the antibiofilm effect compared with the effect of single processing against multilayered plant pathogen biofilms. These findings show that the combination of hexapeptides and NPB can be potentially applied for improving crop production.

Flexible, wavelength-tunable OLED patches promote wound healing via PBM and leverage PBM-induced ROS as endogenous triggers for on-demand drug release, establishing an integrated phototherapy–drug delivery platform for combination therapy.