Fabrication of a Bionic Needle with both Super-Hydrophobic and Antibacterial Properties

Many biological surfaces possess unusual micro-nano hierarchical structures that could influence their wettability, which provide new methods for the construction of novel materials. In this work, silver nanoparticles were successfully coated on the surface of stainless steel needle by a simple electroless replacement reaction process between the AgNO₃ solution and the activated stainless steel needle. After the replacement reaction, porous micro/nanostructures were formed on the surface of the stainless steel needle. By modifying long chains of thiol molecules, the stainless steel needle exhibited good super-hydrophobic property with a contact angle greater than 150°. Moreover, the silver coated stainless steel needle (bionic needle) showed strong antibacterial activity against the gram-negative bacterium Escherichia coli (E. coli). By calculating the area of the inhibition zone against E. coli formed on agar medium, the antibacterial activity of the bionic needle with the contact angle of 152° is much better than that with the contact angle of 138°. The as-prepared bionic needle with both super-hydrophobic and antibacterial properties has the potential to be applied in modern medical devices.