Skin is the outermost layer of the human body that is constantly exposed to environmental stressors, such as UV radiation and toxic chemicals, and is susceptible to mechanical wounding and injury. The ability of the skin to repair injuries is paramount for survival and it is disrupted in a spectrum of disorders leading to skin pathologies. Diabetic patients often suffer from chronic, impaired wound healing, which facilitate bacterial infections and necessitate amputation. Here, we studied the effects of gallic acid (GA, 3,4,5-trihydroxybenzoic acid; a plant-derived polyphenolic compound) on would healing in normal and hyperglucidic conditions, to mimic diabetes, in human keratinocytes and fibroblasts. Our study reveals that GA is a potential antioxidant that directly upregulates the expression of antioxidant genes. In addition, GA accelerated cell migration of keratinocytes and fibroblasts in both normal and hyperglucidic conditions. Further, GA treatment activated factors known to be hallmarks of wound healing, such as focal adhesion kinases (FAK), c-Jun N-terminal kinases (JNK), and extracellular signal-regulated kinases (Erk), underpinning the beneficial role of GA in wound repair. Therefore, our results demonstrate that GA might be a viable wound healing agent and a potential intervention to treat wounds resulting from metabolic complications.
In the case of low-surface-tension liquids, such as oils, wetting becomes a major concern if the liquid spreads easily at the interface and between the fibrils. Even though carefully controlled, thin layers of viscous oil (0.1-2.1 µm thick) applied on the fibril tips of artificial dry adhesives can enhance adhesion on both smooth and rough surfaces, [17-19] larger volumes of liquids (0.1-0.4 µL) at the solid-solid interface have been shown to drop adhesion to a fraction compared to dry conditions. [20] For overall adhesion performance in various wetting conditions, it would be advantageous to displace (push away) liquid from the contact interface and make a dry contact. Preferably all liquids, regardless of their surface tension, should remain in the Cassie state (i.e., the liquid droplet staying suspended on top of the fibrils), even during contact with the target surface. The transition barrier to the Wenzel state (i.e., the droplet fully wetting the substrate and fibrils) should also be sufficiently high to provide robust liquid repellency, since the adhesion would drop drastically in the Wenzel state. Combining high adhesion and low-surface-tension liquid repellency on the same fibrillar surface has not been possible yet as the two properties have fundamentally opposing requirements for solid fraction (the fraction of the solid surface in contact with the liquid or the solid surface to adhere)-it should be large for adhesion and small for liquid repellency. Furthermore, high liquid repellency has been traditionally achieved by a combination of surface chemistry and roughness modification, an approach which is typically incompatible with the goal of high adhesion. For example, sprayable coatings can be extremely effective at turning a surface superrepellent to all liquids, [21,22] but they rely on ultralow surface energy and hierarchical microand nanoscale roughness, both of which are detrimental to adhesion. Another prominent avenue for achieving repellency toward low-surface-tension liquids is based on arrays of microscale features with re-entrant geometry, [23] inspired by the skin of springtails. In recent years, this approach has been taken further by the introduction of double re-entrant structures, which can repel all liquids regardless of surface chemistry. [24,25] However, the fabrication techniques have mostly focused on rigid materials, which are not suitable for dry adhesives involving elastomeric compliant fibrils. Although rigid double reentrant structures for liquid repellency have been fabricated on flexible substrates, [25-27] and compliant double re-entrant structures have been demonstrated by shape-altering metal Bioinspired elastomeric fibrillar surfaces have significant potential as reversible dry adhesives, but their adhesion performance is sensitive to the presence of liquids at the contact interface. Like their models in nature, many artificial mimics can effectively repel water, but fail when low-surface-tension liquids are introduced at the contact interface. A bioinspired fibrillar a...
This paper introduces a new five-dimensional localization method for an untethered meso-scale magnetic robot, which is manipulated by a computer-controlled electromagnetic system. The developed magnetic localization setup is a two-dimensional array of mono-axial Hall-effect sensors, which measure the perpendicular magnetic fields at their given positions. We introduce two steps for localizing a magnetic robot more accurately. First, the dipole modeled magnetic field of the electromagnet is subtracted from the measured data in order to determine the robot’s magnetic field. Secondly, the subtracted magnetic field is twice differentiated in the perpendicular direction of the array, so that the effect of the electromagnetic field in the localization process is minimized. Five variables regarding the position and orientation of the robot are determined by minimizing the error between the measured magnetic field and the modeled magnetic field in an optimization method. The resulting position error is 2.1±0.8 mm and angular error is 6.7±4.3° within the applicable range (5 cm) of magnetic field sensors at 200 Hz. The proposed localization method would be used for the position feedback control of untethered magnetic devices or robots for medical applications in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.