An antibacterial hydrogel coating with pH-regulated rifampicin loading for prevention of catheter-associated infections

Medical catheters often fail due to bacterial infections during clinical use. An antibacterial coating offers an effective material solution to this issue. Herein, we prepared a polyelectrolyte hydrogel coating with tunable antibiotic loading. The crosslinked poly(2-acrylamido-2-methylpropanesulfonic acid sodium salt) (pAN) hydrogel coating was prepared by initiator pre-entrapment and in situ UV initiation. The sulfonate groups in pAN enable efficient hydrophobic rifampicin (RIF) loading via electrostatic interactions with the antibiotic's positively charged groups. RIF loading could reach 119.3 ± 10.8 μg cm−2 at pH 2.0 and remain tunable (the range >100 μg cm−2) across a pH range of 2.0–9.5 due to pH-dependent charge modulation. Additionally, the sulfonated polyelectrolyte simultaneously offered excellent hydrophilic lubricity with a coefficient of friction <0.03 and anticoagulant properties. Such a multifunctional hydrogel coating with antibacterial, lubricating, and anticoagulant properties provides a promising approach to reducing catheter-associated infections, equipping medical polymer-based catheters with better practical performance.