By immersing in dopamine solution (2 mg/mL tris-HCl buffer, pH 8.5) overnight, oxidative self-polymerization of dopamine enables microporous polyethylene (PE) membrane and electrospun polyacrylonitrile (PAN) nanofibers surface to be deposited with a polydopamine thin layer. As observed by Field Emission - Scanning Electron Microscope (FE-SEM) and Atomic Force Microscope (AFM), the micro-sized pores of porous PE and the surface of PAN nanofibers are covered by the uniformly deposited polydopamine layer. The hydrophobicity of original surface decreased significantly after dopamine treatment. The polydopamine has a good reducing power that silver metal surfaced membrane was obtained after immersing the polydopamine coated membrane in silver nitrate solution. Another attempt to deposit silver nanoparticles on the surface of PAN nanofibers were conducted by hydrolyzing the nitrile groups on nanofibers’ surface to formed carboxylate groups. Ion exchange was conducted to graft the silver ion along the nanofibers, followed by heat reduction process, the nanofiber surface is consisted of uniformly distributed silver nanoparticles as analyzed by FE-SEM, AFM, UV-visible spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), and Electrokinetic analyzer (BI-EKA). The quantification of silver content deposited on membrane was accomplished by using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The silver nanoparticles deposited membrane has a superior antimicrobial efficacy against Gram negative and positive bacteria, Escherichia coli and Bacillus subtilis respectively as demonstrated by forming clear inhibition zone surrounds the membranes in the bacterial agar plates. In contrast, the silver nanoparticles deposited membrane supported the growth of mouse fibroblast L929 cells rather than inhibited.

By immersing in dopamine solution (2 mg/mL tris-HCl buffer, pH 8.5) overnight, oxidative self-polymerization of dopamine enables microporous polyethylene (PE) membrane and electrospun polyacrylonitrile (PAN) nanofibers surface to be deposited with a polydopamine thin layer. As observed by Field Emission - Scanning Electron Microscope (FE-SEM) and Atomic Force Microscope (AFM), the micro-sized pores of porous PE and the surface of PAN nanofibers are covered by the uniformly deposited polydopamine layer. The hydrophobicity of original surface decreased significantly after dopamine treatment. The polydopamine has a good reducing power that silver metal surfaced membrane was obtained after immersing the polydopamine coated membrane in silver nitrate solution. Another attempt to deposit silver nanoparticles on the surface of PAN nanofibers were conducted by hydrolyzing the nitrile groups on nanofibers’ surface to formed carboxylate groups. Ion exchange was conducted to graft the silver ion along the nanofibers, followed by heat reduction process, the nanofiber surface is consisted of uniformly distributed silver nanoparticles as analyzed by FE-SEM, AFM, UV-visible spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), and Electrokinetic analyzer (BI-EKA). The quantification of silver content deposited on membrane was accomplished by using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The silver nanoparticles deposited membrane has a superior antimicrobial efficacy against Gram negative and positive bacteria, Escherichia coli and Bacillus subtilis respectively as demonstrated by forming clear inhibition zone surrounds the membranes in the bacterial agar plates. In contrast, the silver nanoparticles deposited membrane supported the growth of mouse fibroblast L929 cells rather than inhibited.

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