A biphasic multilayer computational model of human skin.
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ABSTRACT:
SUBMITTER: Sachs D
PROVIDER: S-EPMC8154831 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:To develop a wound dressing material that conforms to the healing process, we prepared a multilayer composite (MC) membrane consisting of an antibacterial layer (ABL), a reinforcement layer (RFL), and a healing promotion layer (HPL). Biocompatible zein/ethyl cellulose (zein/EC) electrospun nanofibrous membranes with in situ loaded antibacterial photosensitizer protoporphyrin (PPIX) and healing promotion material vaccarin (Vac) were, respectively, chosen as the ABL on the surface and the HPL on the bottom, between which nonwoven incorporated bacterial cellulose (BC/PETN) as the HPL was intercalated to enhance the mechanical property. Photodynamic antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa was confirmed by the enlarged inhibition zones; meanwhile, satisfactory biocompatibility of the HPL was verified by scanning electronic microscopy (SEM) of L929 cells cultured on its surface. The potential effects on wound healing in a mice skin defect model of the MC membranes were also evaluated. The animal experiments demonstrated that the wound healing rate in the MC group was significantly increased compared with that in the control group (p < 0.05). Histopathological observation revealed an alleviated inflammatory response, accompanied with vascular proliferation in the MC group. The MC membranes significantly promoted wound healing by creating an antibacterial environment and promoting angiogenesis. Taken together, this MC membrane may act as a promising wound dressing for skin wound healing.
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Project description:Improvements in quantitative measurements of human physical activity are proving extraordinarily useful for studying the underlying musculoskeletal system. Dynamic models of human movement support clinical efforts to analyze, rehabilitate injuries. They are also used in biomechanics to understand and diagnose motor pathologies, find new motor strategies that decrease the risk of injury, and predict potential problems from a particular procedure. In addition, they provide valuable constraints for understanding neural circuits. This paper describes a physics-based movement analysis method for analyzing and simulating bipedal humanoid movements. The model includes the major body segments and joints to report human movements' energetic components. Its 48 degrees of freedom strike a balance between very detailed models that include muscle models and straightforward two-dimensional models. It has sufficient accuracy to analyze and synthesize movements captured in real-time interactive applications, such as psychophysics experiments using virtual reality or human-in-the-loop teleoperation of a simulated robotic system. The dynamic model is fast and robust while still providing results sufficiently accurate to be used to animate a humanoid character. It can also estimate internal joint forces used during a movement to create effort-contingent stimuli and support controlled experiments to measure the dynamics generating human behaviors systematically. The paper describes the innovative features that allow the model to integrate its dynamic equations accurately and illustrates its performance and accuracy with demonstrations. The model has a two-foot stance ability, capable of generating results comparable with an experiment done with subjects, and illustrates the uncontrolled manifold concept. Additionally, the model's facility to capture large energetic databases opens new possibilities for theorizing as to human movement function. The model is freely available.
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Project description:BackgroundThe detection and dissection of epidermal subgroups could lead to an improved understanding of skin homeostasis and wound healing. Flow cytometric analysis provides an effective method to detect the surface markers of epidermal cells while producing high-dimensional data files.MethodsA 9-color flow cytometric panel was optimized to reveal the heterogeneous subgroups in the epidermis of human skin. The subsets of epidermal cells were characterized using automated methods based on dimensional reduction approaches (viSNE) and clustering with Spanning-tree Progression Analysis of Density-normalized Events (SPADE).ResultsThe manual analysis revealed differences in epidermal distribution between body sites based on a series biaxial gating starting with the expression of CD49f and CD29. The computational analysis divided the whole epidermal cell population into 25 clusters according to the surface marker phenotype with SPADE. This automatic analysis delineated the differences between body sites. The consistency of the results was confirmed with PhenoGraph.ConclusionA multicolor flow cytometry panel with a streamlined computational analysis pipeline is a feasible approach to delineate the heterogeneity of the epidermis in human skin.
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Project description:Bioinspired and adhesive multilayer membranes are produced using the layer-by-layer (LbL) assembly of chitosan (CHT), alginate (ALG) and hyaluronic acid modified with dopamine (HA-DN). Freestanding multilayer membranes without DN are also produced as a control. The success of the synthesis of HA-DN was confirmed using UV-visible spectroscopy. Scanning electron microscopy images indicate that the surface of the DN-containing membranes is more porous than the control ones; they also present a higher average thickness value for the same number of CHT/ALG/CHT/HA(-DN) tetralayers (n = 100). Also, water uptake, mechanical strength and adhesion are enhanced with the introduction of DN moieties along the nano-layers. Besides, human dermal fibroblast viability, enhanced adhesion and proliferation were confirmed by immunofluorescence assays and by measuring both the metabolic activity and DNA content. Moreover, in vivo assays with such kinds of DN-containing multilayer membranes were performed; the application of these membranes in the treatment of dermal wounds induced in Wistar rats results in the highest decrease of inflammation of rat skin, compared with the control conditions. Overall, this investigation suggests that these mussel-inspired freestanding multilayer membranes may enhance either their mechanical performance or cellular adhesion and proliferation, leading to an improved wound healing process, being a promising material to restore the structural and functional properties of wounded skin.
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