Co-immobilization of Palm and DNase I for the development of an effective anti-infective coating for catheter surfaces

Abstract

Catheter-associated infections (CAI) are the most common hospital-acquired infections worldwide. Several coating strategies have been proposed to fight these infections but most of them present some important limitations, including the emergence of resistant bacteria and toxicity concerns. The present work describes a two-step polydopamine-based surface modification strategy to successfully co-immobilize an antimicrobial peptide (Palm) and an enzyme targeting an important component of biofilm matrix (DNase I). This immobilization approach imparted polydimethylsiloxane surfaces with both anti-adhesive and antimicrobial properties against the adhesion of relevant bacteria as single and dual-species, with excellent stability and biocompatible and anti-biofilm properties, holding, therefore, great potential in the development of catheters able to prevent CAI.

Unveiling the fate of adhering bacteria to antimicrobial surfaces: expression of resistance-associated genes and macrophage-mediated phagocytosis

“…After allowing bacterial adhesion for 4 h to the different surfaces ( Fig. 4A-C), it was possible to observe that the number of adhered bacteria to functionalized surface MIX was lower than on control surfaces, corroborating previous findings [23]. After 2 h exposure to RPMI media without macrophages, the fraction of adhered bacteria to PDMS slightly increased (Fig.…”

“…Despite the promising results reported in the literature, where reductions on bacterial attachment higher than 90% are often achieved [17], most of these approaches tend to disregard the fate of the few bacteria that manage to attach to these modified surfaces. In our previous work, the co-immobilization of DNase I and Palm onto PDMS yielded a promising coating strategy with excellent anti-adhesive and antimicrobial properties without cytotoxicity [23]. However, it could not be neglected the fact that some bacteria managed to adhere to these coatings.…”

“…Indeed, mature biofilms are less likely to form if macrophages can remove and destroy bacteria adhering on a biomaterial surface. For further evaluation of the clinical potential of our bi-functional coating previously proposed [23] the in vitro response of human macrophages to S. aureus adhering to these coatings was also investigated and compared to unmodified surfaces. Results showed that macrophages were better distributed along pDA surfaces which suggests a better mobility to perform their phagocytic activity.…”

“…PDMS (kit Sylgard 184, Dow Corning, USA) was prepared and functionalized with the lipopeptide Palm and enzyme DNase I as previously described [23]. Briefly, the first step involved the deposition of a polydopamine (pDA) coating onto PDMS coupons which was performed by immersing them in 7 mL of a freshly prepared solution of dopamine (Sigma, 2 mgÁmL À1 dopamine-HCl in 10 mM bicine buffer, pH 8.5, Sigma) for 18 h at room temperature (RT) and under agitation (70 rpm).…”

“…In our previous work, the antimicrobial peptide Palm and the enzyme DNase I were successfully co-immobilized onto PDMS surfaces to impart them with both anti-adhesive and antimicrobial properties against the adhesion of relevant bacteria as single and dual-species, with excellent stability and non-toxicity [23]. Although the results obtained were quite promising, it cannot be neglected the fact that some bacteria managed to adhere to these coatings.…”