We have developed prototype hydrogel wound dressings which respond to the cytotoxins secreted by bacteria in wounds as the wound becomes critically colonised with pathogenic bacteria. The dressing (like the SPaCE sensor) responds to the four primary wound microbes:
Following injury, bacteria start to colonise a wound within seconds. Most small wounds heal without infection, but some wounds become infected. The problem is there is no clincially accepted definition of wound infection. Looking at the schematic (right), illustrates the change in bacterial density in a wound which is healing (blue line) or infected (red). Note that the initial trajectory of the infected / non-infected wounds are the same. The divergence point is the Critical Colonisation Threshold (CCT).
We believe the CCT is the earliest point in the wound healing / infection continuum at which wound infection can be detected. Our infection sensor contains phospholipid vesicles (left) dispersed in a gel matrix which are lysed by bacterial toxins secreted at the CCT. The vesicles contain a high concentration, non-toxic dye, carboxyfluorescein, which becomes fluorescent on dilution outside of the vesicle in the hydrogel matrix.
An array of vesicle patches in a gel matrix. Comfortable to wear. Dressing and components are non-toxic and safe.
The dressing research programme began in 2010 with funding from the European Commission, subsequently the EPSRC and Medical Research Council.
The team consisting of scientists at the University of Bath and clinicians at Bristol Children's Hospital and the QVH Hospital, East Grinstead has published over a dozen peer reviewed papers about the underpinning science.
The dressing should be effective for most acute and chronic wounds but our initial patient focus is children with small scald burns. 40,000 children in England & Wales are burned severely enough to need hospital attention each year.
We have trialled the dressing on patients from the BRCH, Southmead hospital (Bristol), QVH (East Grinstead) and the Chelsea & Westminster hospital (London) in an ex-vivo clinical study: EVIDEnT.