Cecropin-Melittin Functionalized Polyurethane Surfaces Prevent Staphylococcus epidermidis Adhesion without Inducing Platelet Adhesion and Activation

Infections and thrombus formation are major concerns for the success of blood-contacting medical devices. Antimicrobial coatings based on antimicrobial peptides (AMPs) are described as promising strategies to fight biomaterial-associated infections. However, their efficiency in the presence of plasma and their effect on platelets adhesion/activation, essential for blood contact applications, is not known. In this work, the AMP cecropin-melittin (CM) is covalently immobilized onto polyurethane (PU) films envisaging a coating for intravascular catheters. Immobilization is done by dip-coating of a layer of gold nanoparticles (Au NPs) functionalized with-NH2 and-COOH terminated polyethylene glycol (PEG). Surfaces characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), quartz crystal microbalance with dissipation (QCM-D), and colorimetric assays reveal a stable and homogeneous coating distribution. CM coating significantly reduces Staphylococcus epidermidis adhesion to PU films (approximate to 80% in PBS). Its bactericidal activity is not affected in the presence of 1% human plasma (hPlasma) proteins with 65% reduction on viable bacteria comparing to PU. Moreover, CM coating is able to prevent platelet adhesion/activation to PU films (approximate to 95% in PBS). This effect is also observed when surfaces are precoated with hPlasma. Overall, the developed antimicrobial coating demonstrates great potential to prevent bacterial infections on PU devices without instigating platelet adhesion/activation.