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 <i>in situ</i> UV initiation. The sulfonate groups in pAN enable efficient hydrophobic rifampicin (RIF) loading <i>via</i> 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.