Investigating the microbial and metalloprotease sequestration properties of superabsorbent wound dressings

Abstract

Exudate production is a natural part of the wound healing process, however levels of exudate need to be appropriately managed to maintain a moist wound environment which supports healing. An overly-exuding wound creates an environment favourable to bacterial growth. In recent years, a significant increase in commercially available superabsorbent dressings have become available which claim to absorb and retain excess exudate and its components. However, the effectiveness of these dressings in sequestering and retaining bacteria and host-derived proteins has not been compared. We have therefore investigated several superabsorbent dressings for their ability to absorb and retain bacteria (Staphylococcus aureus and Pseudomonas aeruginosa), their impact on bacterial viability, and their ability to sequester matrix metalloproteinases (MMP)-2 and 9 over 7 days. Whilst all dressings could sequester bacteria, some dressings internalised bacteria more effectively. There was considerable variation in bacterial viability within the dressings’ core, as well as differences in bacterial retention. Some dressings effectively internalised and retained bacteria over time, whereas other dressings retained significantly less. These differences were reflected visually using scanning electron microscopy. Most dressings fully sequestered MMP-2 and 9. These data illustrate differences in the ability of superabsorbent dressings to absorb and retain exudate and its components.

Ability of Different Non-Antimicrobial Wound Dressings to Remove Bacteria from Surfaces Using in vitro Planktonic and Mature Biofilm Models

“…28,29 The ability of CMC dressings to most effectively remove antibiotic-resistant P. aeruginosa and MRSA bacteria in both planktonic and biofilm forms suggests they may play an effective role in reducing bioburden in the management of acute and hard-to-heal wounds in a clinical setting. Our study has tested a small but representative number of different dressing technologies, yet there are other dressings that claim to sequester or retain bacteria 30 and hence further testing of such dressings is warranted.…”

Fluid handling by foam wound dressings: From engineering theory to advanced laboratory performance evaluations

“…[22][23][24][25][26][27] Additionally, exudates may harbour various microorganisms, some pathogenic, contributing to wound deterioration. 28,29 Overall, these variable exudate components altogether determine the physicochemical properties of the fluid, including its surface energy 4 and surface tension, as well as its viscosity, which in turn influence the ability of the exudate to be effectively absorbed, and once absorbed, spread within the dressing structure, including under gravitational or any external (compressive, shear or combined) forces that may deform the dressing (Figure 2).…”

“…Differences include pH levels, nutrient and mineral content, proteins, electrolytes, inflammatory mediators, enzymes (e.g., MMPs), growth factors (e.g., basic fibroblast growth factor) and cellular elements (e.g., neutrophils, macrophages and platelets) 22–27 . Additionally, exudates may harbour various microorganisms, some pathogenic, contributing to wound deterioration 28,29 . Overall, these variable exudate components altogether determine the physico‐chemical properties of the fluid, including its surface energy 4 and surface tension, as well as its viscosity, which in turn influence the ability of the exudate to be effectively absorbed, and once absorbed, spread within the dressing structure, including under gravitational or any external (compressive, shear or combined) forces that may deform the dressing (Figure 2).…”

Modification of Superabsorbent Polymer Granules and Fibers for Antimicrobial Efficacy and Malodor Control

“…An estimated three million tons of superabsorbent polymer (SAP) granules are produced annually, primarily for use in absorptive cores of diapers, incontinence devices, mattress pads, and feminine hygiene pads. , SAPs are also incorporated into wound dressings to improve wound healing. − Retention of biological fluids with these devices is accomplished by the massive absorptive capacity of the cross-linked polymer granules, ranging between 10 and 1000 g of water per gram of SAP. These are often combined with high-surface-area cellulose fluff pulp fibers, which rapidly disperse liquid but have limited absorptive capacity. , In many applications, the accumulation of organic materials in these products results in microbial growth, exoenzyme secretion, and the formation of malodorous volatile reaction products .…”