No abstract

The electrostatic interaction between emerging quantum-confined nanostructures with plasmonic structures is crucial for future biological applications. Water-soluble green fluorescent copper nanoparticles (Cu-NPs) were fabricated. We demonstrate that L-ascorbic acid is considered as a key to precisely control small Cu-NPs and the capability of the surface ligands, while cetyltrimethylammonium bromide is used as a stabilizing agent controls the particle growth, and stabilizes the nanoparticles. Water-soluble green fluorescent Cu-NPs are tunable through modification of the reaction periods.

To improve the antibacterial performance of poly(ethylene-co-acrylic acid) (PEAA) copolymer, aliphatic quaternary ammonium salts (QASs) was grafted into PEAA copolymers via a Steglich esterification reaction using N,N 0 -dicyclohexylcarbodiimide (DCC) as a dehydrating agent. The polymers were synthesized using dodecyl dimethyl hydroxyethyl ammonium chloride (DDHAC), which was prepared by quaternization of dimethylethanolamine (DMEA) with 1-chlorododecane. These polymers effectively inhibited the growth of microorganisms due to their hydrophobic chains, which were bound to PEAA copolymers. The obtained PEAA-g-DDHAC (PGD) was investigated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), proton nuclear magnetic resonance ( 1 H NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and antibacterial tests. The results showed that the antibacterial effects of PGDs were significantly improved by alkyl grafting, and this improvement depended on reaction temperature. The highest antibacterial activity was observed for polymers synthesized at 135 C against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Their decomposition rate was accelerated as the temperature increased above 165 C because of the thermal decomposition of DDHAC.