Development of Microfluidic Wound Models for Testing Skin Wound Healing
Canada spends approximately $3.9 billion towards wound care management annually through several programs. Due to lack of clinically relevant in-vitro and ex-vivo models, our understanding of the wound associated biofilm infections is limited. For designing effective therapeutic strategies to impede bacterial biofilm colonization and for preventing the development of polymicrobial infections, novel wound model systems are essential. The aim of this project is to develop 3D modular microfluidic skin equivalent wound systems that can reflect the polymicrobial, multicellular and pathobiological complexities. The end results of this project will facilitate the drug screening and rapid testing of efficacies of antibiotics and antimicrobial agents produced by biotechnology and pharmaceutical industries.
Collagen and Hyaluronan at Wound Sites Influence Early Polymicrobial Biofilm Adhesive Events
Background
Wounds can easily become chronically infected, leading to secondary health complications, which occur more frequently in individuals with diabetes, compromised immune systems, and those that have suffered severe burns. When wounds become chronically infected, biofilm producing microbes are often isolated from these sites. The presence of a biofilm at a wound site has significant negative impact on the treatment outcomes, as biofilms are characteristically recalcitrant to removal, in part due to the formation of a protective matrix that shield residents organisms from inimical forces. Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) are two of the organisms most prevalently isolated from wound sites, and are of particular concern due to their elevated levels of antibiotic resistance, rapid growth, and exotoxin production. In order to understand the biofilm forming abilities of these microbes in a simulated wound environment we used a microtiter plate assay to assess the ability of these two organisms to bind to proteins that are typically found at wound sites: collagen and hyaluronan.
Results
Collagen and hyaluronan were used to coat the wells of 96-well plates in collagen:hyaluronan ratios of 0:1, 3:1, 1:1, 1:3, and 1:0 . P. aeruginosa and MRSA were inoculated as mono- and co cultures (1:1 and a 3:1 MRSA: P. aeruginosa). We determined that coating the wells with collagen and/or hyaluronan significantly increased the biofilm biomass of attached cells compared to an uncoated control, although no one coating formulation showed a significant increase compared to any other combination. We also noted that the fold-change increase for MRSA upon coating was greater than for P. aeruginosa.
Conclusions
Our study suggests that the presence of collagen and/or hyaluronan at wound sites may be an important factor that influences the attachment and subsequent biofilm formation of notorious biofilm-formers, such as MRSA and P. aeruginosa. Understanding the kinetics of binding may aid in our comprehension of recalcitrant wound infection development, better enabling our ability to design therapies that would prevent or mitigate the negative outcomes associated with such infections.