4 research outputs found
Raman Spectroscopy Enables Noninvasive Biochemical Characterization and Identification of the Stage of Healing of a Wound
Accurate
and rapid assessment of the healing status of a wound in a simple
and noninvasive manner would enable clinicians to diagnose wounds
in real time and promptly adjust treatments to hasten the resolution
of nonhealing wounds. Histologic and biochemical characterization
of biopsied wound tissue, which is currently the only reliable method
for wound assessment, is invasive, complex to interpret, and slow.
Here we demonstrate the use of Raman microspectroscopy coupled with
multivariate spectral analysis as a simple, noninvasive method to
biochemically characterize healing wounds in mice and to accurately
identify different phases of healing of wounds at different time-points.
Raman spectra were collected from “splinted” full thickness
dermal wounds in mice at 4 time-points (0, 1, 5, and 7 days) corresponding
to different phases of wound healing, as verified by histopathology.
Spectra were deconvolved using multivariate factor analysis (MFA)
into 3 “factor score spectra” (that act as spectral
signatures for different stages of healing) that were successfully
correlated with spectra of prominent pure wound bed constituents (i.e.,
collagen, lipids, fibrin, fibronectin, etc.) using non-negative least squares
(NNLS) fitting. We show that the factor loadings (weights) of spectra
that belonged to wounds at different time-points provide a quantitative
measure of wound healing progress in terms of key parameters such
as inflammation and granulation. Wounds at similar stages of healing
were characterized by clusters of loading values and slowly healing
wounds among them were successfully identified as “outliers”.
Overall, our results demonstrate that Raman spectroscopy can be used
as a noninvasive technique to provide insight into the status of normally
healing and slow-to-heal wounds and that it may find use as a complementary
tool for real-time, <i>in situ</i> biochemical characterization
in wound healing studies and clinical diagnosis
Inhibition of Pseudomonas aeruginosa biofilm formation on wound dressings
Chronic nonhealing skin wounds often contain bacterial biofilms that prevent normal wound healing and closure and present challenges to the use of conventional wound dressings. We investigated inhibition of Pseudomonas aeruginosa biofilm formation, a common pathogen of chronic skin wounds, on a commercially available biological wound dressing. Building on prior reports, we examined whether the amino acid tryptophan would inhibit P. aeruginosa biofilm formation on the three-dimensional surface of the biological dressing. Bacterial biomass and biofilm polysaccharides were quantified using crystal violet staining or an enzyme linked lectin, respectively. Bacterial cells and biofilm matrix adherent to the wound dressing were visualized through scanning electron microscopy. D-/L-tryptophan inhibited P. aeruginosa biofilm formation on the wound dressing in a dose dependent manner and was not directly cytotoxic to immortalized human keratinocytes although there was some reduction in cellular metabolism or enzymatic activity. More importantly, D-/L-tryptophan did not impair wound healing in a splinted skin wound murine model. Furthermore, wound closure was improved when D-/L-tryptophan treated wound dressing with P. aeruginosa biofilms were compared with untreated dressings. These findings indicate that tryptophan may prove useful for integration into wound dressings to inhibit biofilm formation and promote wound healing