The use of light for sterilization is very well known in the scientific literature. However, the recent pandemic outbreak and the antimicrobial resistance question drew attention to this topic: to design new light sources for preventing viral epidemic spread is of utmost importance, as an alternative use of chemicals and drugs. Here we present the preliminary ex vivo studies aiming at verifying the potential of new UVC light sources as barriers to the spread of airborne viruses and bacteria. The emitted light is at very short wavelengths (around 220 nm): optical penetration in biological media is limited to a few micrometers, thus preventing the possible damages to the skin and the cornea; the absorption of RNA/DNA shows a minimum at 230 nm, increasing at shorter wavelengths. In this study we optimized a UVC commercial excimer lamp to design a light barrier. The sterilization efficacy has been tested in vitro in cultured Staphylococcus aureus, Pseudomonas aeruginosa and in Sars-Cov-2. The results point out a strong antimicrobial effect (<99.9% bacteria reduced) at ∼15 mJ/cm2 (corresponding to 1 minute treatment time @0.25 mW/cm2). The designed prototype can thus be proposed as a light barrier for preventing contamination, reducing the risks for human beings.
We describe the implementation of hierarchical materials made of hydrophilic micro-droplets in a silicone continuous phase to mimic the interactions of bio-tissue with multiple physical agents, such as those implied in photoacoustic imaging.
Marfan syndrome (MFS) is an inherited disorder of connective tissue due to mutations in FBN1 (90%) and TGFBR1 and TGFBR2 (5 to 10%) genes. Clinical and differential diagnosis is difficult because of the inter- and intrafamiliar marked heterogeneity and the variable onset age of clinical manifestations. Among the disorders, in differential diagnosis, thoracic aortic aneurysm (TAA) and Ullrich scleroatonic muscular dystrophy (UCMD) are reported. We evaluate the possibility of utilizing autofluorescence (AF) analysis as a diagnostic tool in the clinical and/or differential diagnosis of MFS and related disorders and in the investigation of the molecular mechanisms involved. Both multispectral imaging autofluorescence microscopy (MIAM) and autofluorescence microspectroscopy (AMS) have been used to characterize AF emission of fibroblasts from patients affected by inherited connective tissue disorders. Our preliminary results show significant differences in AF emission between normal and pathological fibroblasts, suggesting possible improvement in diagnostics of connective tissue disorders by AF analysis.
Many studies demonstrated that mechanical stress is a key factor for tissue homeostasis, while unloading induce loss of
mass and impairment of function. Because of their physiological function, muscle, connective tissue, bone and cartilage
dynamically interact with mechanical and gravitational stress, modifying their properties through the continuous
modification of their composition. Indeed, it is known that mechanical stress increases the production of extracellular
matrix (ECM) components by cells, but the mechanotransduction mechanisms and the optimal loading conditions
required for an optimal tissue homeostasis are still unknown. Considering the importance of cell activation and ECM
production in tissue regeneration, a proper use of mechanical stimulation could be a powerful tool in tissue repair and
tissue engineering.
Studies exploring advanced modalities for supplying mechanical stimuli are needed to increase our knowledge on
mechanobiology and to develop effective clinical applications.
Here we describe the effect of photomechanical stress, supplied by a pulsed Nd:YAG laser on ECM production by cells
of connective tissues.
Cell morphology, production of ECM molecules (collagens, fibronectin, mucopolysaccharides), cell adhesion and cell
energy metabolism have been studied by using immunofluorescence and autofluorescence microscopy. The results show
that photomechanical stress induces cytoskeleton remodelling, redistribution of membrane integrins, increase in
production of ECM molecules. These results could be of consequence for developing clinical protocols for the treatment
of connective tissue dideases by pulsed Nd:YAG laser.
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