Infrared microscopic imaging of cutaneous wound healing: lipid conformation in the migrating epithelial tongue

Monitoring the Progress and Healing Status of Burn Wounds Using Infrared Spectroscopy

Burns are one of the leading causes of morbidity worldwide and the most costly traumatic injuries. A better understanding of the molecular mechanisms in wound healing is required to accelerate tissue recovery and reduce the health economic impact. However, the standard techniques used to evaluate the biological events associated to wound repair are laborious, time-consuming, and/or require multiple assays/staining. Therefore, this study aims to evaluate the feasibility of Fourier transform infrared (FT-IR) spectroscopy to monitor the progress and healing status of burn wounds. Burn injuries were induced on Wistar rats by water vapor exposure and biopsied for further histopathological and spectroscopic evaluation at four time-points (3, 7, 14, and 21 days). Spectral data were preprocessed and compared by principal component analysis. Pairwise comparison of post-burn groups to each other revealed that metabolic activity induced by thermal injury decreases as the healing progresses. Higher amounts of carbohydrates, proteins, lipids, and nucleic acids were evidenced on days 3 and 7 compared to healthy skin and reduced amounts of these molecular structural units on days 14 and 21 post-burn. FT-IR spectroscopy was used to determine the healing status of a wound based on the biochemical information retained by spectral signatures in each phase of healing. Our findings demonstrate that FT-IR spectroscopy can monitor the biological events triggered by burn trauma as well as to detect the wound status including full recovery based on the spectral changes associated to the biochemical events in each phase.

Isolation and characterization of a respirable particle fraction from residential house-dust

Indoor air pollution has caused increasing concern in recent years. As we spend most of our lives indoors, it is crucial to understand the health effects caused by indoor air pollution. Household dust serve as good proxy for accessing indoor air pollution, especially smaller dust particles that can pass into the lungs are of interest. In this study we present an efficient method for the isolation of dust particles in the respirable size range. The respirable fraction was recovered from vacuum cleaner bags, separated by stepwise sieving, followed by characterization for size, morphology, surface area, organic content and elemental composition. The respirable fraction was obtained in a yield of 0.6% with a specific surface area of 2.5m²/g and a Mass Median Aerodynamic Diameter of 3.73 ± 0.15µm. Aluminum and zink were the dominating metals measured in the dust, whereas the major mineral components were found to be silicon dioxide and calcium carbonate. The fraction of organic matter in the dust was measured to be 69 ± 1%. The organic matrix contained bacterial and fungi and a presence of skin fragments. We present here an efficient and fast method for the isolation of dust particles in the respirable size range. That is of considerable value due to the need for large quantities of respirable particle fractions to conduct toxicological studies and risk assessment work.

Diagnostic and Prognostic Utility of Non-Invasive Multimodal Imaging in Chronic Wound Monitoring: a Systematic Review

Monitoring chronic wound [CW] healing is a challenging issue for clinicians across the world. Moreover, the health and cost burden of CW are escalating at a disturbing rate due to a global rise in population of elderly and diabetic cases. The conventional approach includes visual contour, sketches, or more rarely tracings. However, such conventional techniques bring forth infection, pain, allergies. Furthermore, these methods are subjective as well as time-consuming. As such, nowadays, non-touching and non-invasive CW monitoring system based on imaging techniques are gaining importance. They not only reduce patients' discomfort but also provide rapid wound diagnosis and prognosis. This review provides a survey of different types of CW characteristics, their healing mechanism and the multimodal non-invasive imaging methods that have been used for their diagnosis and prognosis. Current clinical practices as well as personal health systems [m-health and e-health] for CW monitoring have been discussed.

Noninvasive imaging technologies for cutaneous wound assessment: A review

The ability to phenotype wounds for the purposes of assessing severity, healing potential and treatment is an important function of evidence-based medicine. A variety of optical technologies are currently in development for noninvasive wound assessment. To varying extents, these optical technologies have the potential to supplement traditional clinical wound evaluation and research, by providing detailed information regarding skin components imperceptible to visual inspection. These assessments are achieved through quantitative optical analysis of tissue characteristics including blood flow, collagen remodeling, hemoglobin content, inflammation, temperature, vascular structure, and water content. Technologies that have, to this date, been applied to wound assessment include: near infrared imaging, thermal imaging, optical coherence tomography, orthogonal polarization spectral imaging, fluorescence imaging, laser Doppler imaging, microscopy, spatial frequency domain imaging, photoacoustic detection, and spectral/hyperspectral imaging. We present a review of the technologies in use or development for these purposes with three aims: (1) providing basic explanations of imaging technology concepts, (2) reviewing the wound imaging literature, and (3) providing insight into areas for further application and exploration. Noninvasive imaging is a promising advancement in wound assessment and all technologies require further validation.

Novel in vitro approaches for the simulation and analysis of human skin wounds

Considering the increasing incidence of chronic wounds and severe wound infections, effective drug delivery to wounded skin is of high importance. The rational development of novel therapeutic systems requires appropriate in vitro testing methodologies. In this context, suitable and reliable in vitro models simulating human wounds and advanced analytical techniques for precise wound characterization are urgently needed. In this study, we introduce a novel in vitro model based on excised human skin. In contrast to the established wound models, our novel approach has a coffin-shaped, linear, rectangular geometry with defined wound edges exhibiting consistent appearance along the entire wound bed. In addition, we introduce optical profilometry as a novel technique for nondestructive wound analysis. We successfully demonstrate the applicability of this optical imaging method based on white light reflection for three-dimensional visualization of different wound models. Furthermore, we create virtual noninvasive cross sections of these wounds to assess wound geometry in direct comparison to conventional histological analysis. Imaging analysis of our novel coffin-shaped model resulted in reproducible virtual sections along the entire wound bed. Our findings indicate the potential of our novel in vitro model for improved simulation of human wounds. Further, we successfully overcome the limitations of conventional histological analysis by the employment of optical profilometry for nondestructive three-dimensional wound characterization.