Raman Spectroscopy Enables Noninvasive Biochemical Characterization and Identification of the Stage of Healing of a Wound

Abstract

Accurate and rapid assessment of the healing status of a wound in a simple and non-invasive manner would enable clinicians to diagnose wounds in real time and promptly adjust treatments to hasten the resolution of non-healing 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, non-invasive 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 amongst them were successfully identified as ‘outliers’. Overall, our results demonstrate that Raman spectroscopy can be used as a non-invasive 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, in situ biochemical characterization in wound healing studies and clinical diagnosis.

Effect of Cigarette Smoke on Wound Healing of the Septal Mucosa of the Rat

“…Proper wound healing following ESS is influenced by several internal and external factors [ 15 ]. This compound process comprises inflammation, granulation tissue development, and tissue remodeling embracing cell proliferation, angiogenesis, and reepithelization [ 16 ].…”

Comparative study of multivariative analysis methods of blood Raman spectra classification

“…Obtaining statistically reliable information on pathology is possible by using various spectral and chemometric processing methods. For example, when assessing the state of wound healing by means of RS, multivariate factor analysis and non‐negative least squares fitting are able to provide quantitative assessment of the wound healing progress in terms of such key parameters as inflammation and granulation . When analyzing the spectral data of dry traces (blood, semen, and saliva), the discriminant analysis based on the method of soft independent modeling of class analogies ( SIMCAs ), linear discriminant analysis , and projection to latent structures discriminant analysis ( PLS‐DA ) method can be used in criminology for the classification of body fluids .…”

Intense Raman scattering on hybrid Au/Ag nanoplatforms for the distinction of MMP-9-digested collagen type-I fiber detection

“…Skin tissue reconnection with active scaffolds or stem cells is often used to study cell differentiation and proliferation on the wound bed (Jain et al, 2014;Ngo Thi et al, 2014). Biodegradable and nonbiodegradable proteins and peptides are promising supports for tissue reconnection owing to their useful properties, such as chemical structural diversity, large number of architectures, mechanical strength, and biocompatibility (Desimone et al, 2011;Lin et al, 2012;Lv et al, 2014;Shoulders and Raines, 2009).…”

“…From in vitro studies, matrix metalloproteinases (MMPs), including MMP-1, -9, -13, and -14, can effectively degrade native Col-I fibers surrounding a cell surface through the glycine in Col-I fibers (Aimes and Quigley, 1995;Bigg et al, 2007;Fini et al, 1992;Knauper et al, 1997). In addition, the degradation of Col-I, -II, and -III fibers using various temperature-dependent treatments has been investigated (Cárcamo et al, 2012;Jain et al, 2014; Contents lists available at ScienceDirect Su et al, 2014). Methods for analyzing the degradation of Col-I fibers include the enzyme-linked immunosorbent assay and highperformance liquid chromatography (Akhtar et al, 1999;Hudson et al, 2012), which have excellent sensitivity for the detection of specific degraded enzymes in Col-I fibers.…”