One Fast and Accurate In Vitro Model to Assess Ion/Protein Interaction with Antifouling Surfaces In Vivo

Ion and protein adsorption occurs on the implant surface upon contact with tissues. Increasing research efforts focus on modifying or constructing the physical and chemical properties of surfaces to enhance antifouling capabilities. However, conventional in vitro evaluation methods, such as artificial urine and protein immersion models, often fail to replicate the complex interfacial interactions occurring in vivo. In this study, we explored a rabbit bladder implantation model and a biolayer interferometry (BLI) model as in vivo and in vitro systems, respectively, to accurately assess protein and ion interactions on implant surfaces. A series of 2-(Methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC) surfaces with varying degrees of cross-linking were fabricated on BLI fiber optic sensors and ureteral stents using Atom Transfer Radical Polymerization (ATRP). Our observations revealed that increased cross-linking of MPC-modified surfaces correlated with reduced ion and protein adhesion in the bladder implantation model. A similar correlation was noted with the MPC-modified fiber optic sensors. However, an opposite phenomenon was observed in traditional in vitro methods. The agreement between the BLI and rabbit bladder implantation models indicates that the BLI method effectively reflects the in vivo responses of these surfaces, thereby providing a rapid and accurate in vitro model for assessing protein and ion adsorption on implant surfaces in vivo.