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An emerging strategy to improve adhesiveness of biomaterials in wet conditions takes inspiration from the adhesive features of marine mussel, which reside in the chemical reactivity of catechols. In this work, a catechol-bearing molecule (dopamine) was chemically grafted onto alginate to develop a polysaccharide-based membrane with improved adhesive properties. The dopamine-modified alginates were characterized by NMR, UV spectroscopy and in vitro biocompatibility. Mechanical tests and in vitro adhesion studies pointed out the effects of the grafted dopamine within the membranes. The release of HA from these resorbable membranes was shown to stimulate fibroblasts activities ( in vitro ). Finally, a preliminary in vivo test was performed to evaluate the adhesiveness of the membrane on porcine intestine (serosa). Overall, this functionalized membrane was shown to be biocompatible and to possess considerable adhesive properties owing to the presence of dopamine residues grafted on the alginate backbone. Statement of Significance This article describes the development of a mussels-inspired strategy for the development of an adhesive polysaccharide-based membrane for wound healing applications. Bioadhesion was achieved by grafting dopamine moieties on the structural component on the membrane (alginate): this novel biomaterial showed improved adhesiveness to the intestinal tissue, which was demonstrated by both in vitro and in vivo studies. Overall, this study points out how this nature-inspired strategy may be successfully exploited for the development of novel engineered biomaterials with enhanced bioadhesion, thus opening for novel applications in the field of general surgery. [ABSTRACT FROM AUTHOR]

Background Pressure ulcers are a major healthcare problem and caused by pressure and shear-forces. Although shear-force is understood to be a major contributing factor, no preventive interventions are specifically aimed at relieving the effect of shear on skin to improve skin viability. Methods A physical model was used to apply a combined loading of 2.4 kPa pressure and 14.5 N shear-force on skin in humans. Loading was applied on the volar aspect of both forearms for 30 min in ten healthy volunteers. One arm received loading on skin with a wound dressing, the other arm (control) received loading directly on skin. The following parameters were determined before and after loading: IL-1α/Total Protein-ratio (used as a measure of skin damage); Cutaneous blood cell flux ((CBF) measure of reactive hyperaemia); Lactate concentration (measure of tissue ischemia). Three different dressings were tested on three different days. The order of dressing application, dressing arm and start of the intervention were randomized. Results Participants mean age was 22.5±1.6 year with a BMI of 22.3±2.4 kg/m 2 . IL-1α/Total Protein-ratio of the skin was significantly lower after the application of pressure and shear when the Mepilex® ( P <0.01), Allevyn ( P <0.05) or Aquacel TM dressing ( P <0.01) was used compared with the control measurement. The Mepilex® dressing was more effective in reducing post-load IL-1α/Total Protein-ratio compared to the Allevyn dressing ( P <0.01). Post-load CBF was significantly lower when the Mepilex® or Aquacel dressing was used ( P <0.001). Both dressings induced significantly less post-load CBF than the Allevyn dressing ( P <0.01 and P <0.001, respectively). The concentration of lactate was not significantly increased after the application of pressure and shear and could not be used as a measure with this model. Conclusion This is the first in vivo study to demonstrate that the effects of pressure in combination with shear on skin viability can be improved with foam dressings. In this study, the multi-layered dressings perform better than the single-layered dressing. [ABSTRACT FROM AUTHOR]

Sterilization methods such as ɣ-irradiation, steam sterilization and ethylene oxide gas treatment can have negative effects on molecular structure and properties of polysaccharide-based biomaterials. In this perspective, the use of supercritical carbon dioxide (scCO 2 ) has been proposed as an alternative method for biomaterial sterilization. In this work, chemical, mechanical and biological properties of polysaccharidic membranes for surgical applications were investigated after sterilization by scCO 2 . Four sets of sterilizing conditions were considered and SEC analyses were performed in order to identify the one with lower impact on the polysaccharidic matrix of membranes (alginate). Mechanical tests showed that the resistance of membranes was slightly affected after sterilization. Biological analyses proved the biocompatibility of the sterilized membranes both in vitro and in a preliminary in vivo test. Overall, this study points out that this sterilization technique can be successfully employed to achieve an effective and safe sterilization of polysaccharidic membranes for surgical use. [ABSTRACT FROM AUTHOR]