Results of Testing Barrier Dressing on Excised Rats

10 Results of Testing Barrier Dressing on Excised Rats 

Rats were excised (dorsal skin) and a statistical test was initiated to determine the efficacy of the dressing. A contaminated, full thickness excision model was 

Microscopic analysis of the dressing and necrotic rat tissue revealed that the particulate dressing was porous, consisted of 90% water and was vulnerable to microbial attack. The import of material, and therefore dressing composition, is analyzed in Sect. 2.7. However, it is important to realize that any barrier dressing for a wound 

The rate of diffusion (see Fig. 2.33) is controlled by the difference in concentration across the gel, or more conveniently, by the concentration gradient dc/dx where c is the concentration of the water in mass per unit volume of solution. The diffusion rate is found to be proportional to the cross-sectional area A. If the diffusion rate is written dw/dl and the mass of dye (w) transformed across the boundary per second (t), one has Fick s law of diffusion (Barrow 1973), 

Proteus mirabilis bacteria was dispersed in agar before solidifying into a Petri dish, and colonization occurred which seems contradictory for an aerobic microorganism, but is understandable considering the gel structure is permeable to air, water vapor, and nutrients. The previous observation is further reason not to constmct a barrier dressing from an aqueous gel, hydrogel or other similar material containing more than about 20% water where protection from bacteria is a critical requirement. 

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