Superoxide Dismutase-Mimetic Polyphenol-Based Carbon Dots for Multimodal Bioimaging and Treatment of Atopic Dermatitis.

Polyphenols have been investigated for their potential to mitigate inflammation in the context of atopic dermatitis (AD). In this study, epigallocatechin-3-gallate (EGCG)-based carbon dots (EGCG@CDs) were developed to enhance transdermal penetration, reduce inflammation, recapitulate superoxide dismutase (SOD) activity, and provide antimicrobial effects for AD treatment. The water-soluble EGCG@CDs in a few nanometers size exhibit a negative zeta potential, making them suitable for effective transdermal penetration. The fluorescence properties, including an upconversion effect, make EGCG@CDs suitable imaging probes for both in vitro and in vivo applications. By mimicking the SOD enzyme, EGCG@CDs scavenge reactive oxygen species (ROS) and actively produce hydrogen peroxide through a highly catalytic capability toward the oxygen reduction reaction, resulting in the inhibition of bacterial growth. The enhanced antioxidant properties, high charge mobility, and various functional groups of EGCG@CDs prove effective in reducing intracellular ROS in an in vitro AD model. In the mouse AD model, EGCG@CDs incorporated into a hydrogel actively penetrated the epidermal layer, leading to ROS scavenging, reduced mast cell activation, and histological recovery of skin barriers. This research represents the versatile potential of EGCG@CDs in addressing AD and advancing tissue engineering.

Single-Walled Carbon Nanotube-Guided Topical Skin Delivery of Tyrosinase to Prevent Photoinduced Damage.

When the skin is exposed to ultraviolet radiation (UV), it leads to the degradation of the extracellular matrix (ECM) and results in inflammation. Subsequently, melanocytes are triggered to induce tyrosinase-mediated melanin synthesis, protecting the skin. Here, we introduce a proactive approach to protect the skin from photodamage via the topical delivery of Streptomyces avermitilis-derived tyrosinase (SaTy) using single-walled carbon nanotube (SWNT). Utilizing a reverse electrodialysis (RED) battery, we facilitated the delivery of SaTy-SWNT complexes up to depths of approximately 300 µm, as analyzed by using confocal Raman microscopy. When applied to ex vivo porcine skin and in vivo albino mouse skin, SaTy-SWNT synthesized melanin, resulting in 4-fold greater UV/vis absorption at 475 nm than in mice without SaTy-SWNT. The synthesized melanin efficiently absorbed UV light and alleviated skin inflammation. In addition, the densification of dermal collagen, achieved through SaTy-mediated cross-linking, reduced photoinduced wrinkles by 66.3% in the affected area. Our findings suggest that SWNT-mediated topical protein delivery holds promise in tissue engineering applications.

Double Emulsion-Mediated Delivery of Polyphenol Mixture Alleviates Atopic Dermatitis.

Although the polyphenols have been studied to alleviate inflammation, there are still challenges to delivering the polyphenols with stabilized formulation due to their low water solubility and susceptibility to oxidation. Herein, the transdermal delivery system of polyphenol mixture (PM), including quercetin (Q), phloretin (P), and ellagic acid (E), is developed using double emulsion for applying to atopic dermatitis (AD). Through the in vitro anti-degranulation assay, the optimal molar ratio of each polyphenol (Q:P:E = 5:1:1) is obtained, and the PM shows at most a 43.6% reduction of degranulation of immune cells, which is the primary factor of AD. Moreover, the water-in-oil-in-water double emulsion (W/O/W) enhances the PM's stability and has a higher anti-degranulation effect than the oil-in-water emulsion (O/W). In the in vivo 1-chloro-2,4-dinitrobenzene (DNCB)-induced mice AD model, PM reduces more AD symptoms than every single polyphenol. The PM-encapsulated W/O/W (PM_W/O/W) shows the most effectiveness in AD by decreasing dermatitis score, i.e., skin/ear thickness, mast cells, and serum IgE level. Finally, this suggests that the findings on the optimal ratio of PM and double emulsion-based delivery would be beneficial in treating AD and can be applied to other allergic diseases.

Light-Triggered In Situ Biosynthesis of Artificial Melanin for Skin Protection.

Tyrosinase-mediated melanin synthesis is an essential biological process that can protect skin from UV radiation and radical species. This work reports on in situ biosynthesis of artificial melanin in native skin using photoactivatable tyrosinase (PaTy). The I41Y mutant of Streptomyces avermitilis tyrosinase (SaTy) shows enzymatic activity comparable to that of wild-type SaTy. This Y41 is replaced with photocleavable o-nitrobenzyl tyrosine (ONBY) using the introduction of amber codon and ONBY-tRNA synthetase/tRNA pairs. The ONBY efficiently blocks the active site and tyrosinase activity is rapidly recovered by the photo-cleavage of ONBY. The activated PaTy successfully oxidizes L-tyrosine and tyramine-conjugated hyaluronic acid (HA_T) to synthesize melanin particles and hydrogel, respectively. To produce artificial melanin in living tissues, PaTy is encapsulated into lipid nanoparticles as an artificial melanosome. Using liposomes containing PaTy (PaTy_Lip), PaTy is transdermally delivered into ex vivo porcine skin and in vivo mouse skin tissues, thus achieving the in situ biosynthesis of artificial melanin for skin tissue protection under UV irradiation. The results of this study demonstrate that this biomimetic system can recapitulate the biosynthetic analogs of naturally occurring melanin. It should therefore be considered to be a promising strategy for producing protective biological molecules within living systems for tissue protection.

High-Efficient Production of Adipose-Derived Stem Cell (ADSC) Secretome Through Maturation Process and Its Non-scarring Wound Healing Applications.

Recently, the stem cell-derived secretome, which is the set of proteins expressed by stem cells and secreted into the extracellular space, has been demonstrated as a critical contributor for tissue repair. In this study, we have produced two sets of high concentration secretomes from adipose-derived mesenchymal stem cells (ADSCs) that contain bovine serum or free of exogenous molecules. Through proteomic analysis, we elucidated that proteins related to extracellular matrix organization and growth factor-related proteins are highly secreted by ADSCs. Additionally, the application of ADSC secretome to full skin defect showed accelerated wound closure, enhanced angiogenic response, and complete regeneration of epithelial gaps. Furthermore, the ADSC secretome was capable of reducing scar formation. Finally, we show high-dose injection of ADSC secretome via intraperitoneal or transdermal delivery demonstrated no detectable pathological conditions in various tissues/organs, which supports the notion that ADSC secretome can be safely utilized for tissue repair and regeneration.

Recent advancements in enzyme-mediated crosslinkable hydrogels: In vivo-mimicking strategies.

Enzymes play a central role in fundamental biological processes and have been traditionally used to trigger various processes. In recent years, enzymes have been used to tune biomaterial responses and modify the chemical structures at desired sites. These chemical modifications have allowed the fabrication of various hydrogels for tissue engineering and therapeutic applications. This review provides a comprehensive overview of recent advancements in the use of enzymes for hydrogel fabrication. Strategies to enhance the enzyme function and improve biocompatibility are described. In addition, we describe future opportunities and challenges for the production of enzyme-mediated crosslinkable hydrogels.

Enhancement of Wound Healing Efficacy by Increasing the Stability and Skin-Penetrating Property of bFGF Using 30Kc19α-Based Fusion Protein.

The instability of recombinant basic fibroblast growth factor (bFGF) is a major disadvantage for its therapeutic use and means frequent applications to cells or tissues are required for sustained effects. Originating from silkworm hemolymph, 30Kc19α is a cell-penetrating protein that also has protein stabilization properties. Herein, it is investigated whether fusing 30Kc19α to bFGF can enhance the stability and skin penetration properties of bFGF, which may consequently increase its therapeutic efficacy. The fusion of 30Kc19α to bFGF protein increases protein stability, as confirmed by ELISA. 30Kc19α-bFGF also retains the biological activity of bFGF as it facilitates the migration and proliferation of fibroblasts and angiogenesis of endothelial cells. It is discovered that 30Kc19α can improve the transdermal delivery of a small molecular fluorophore through the skin of hairless mice. Importantly, it increases the accumulation of bFGF and further facilitates its translocation into the skin through follicular routes. Finally, when applied to a skin wound model in vivo, 30Kc19α-bFGF penetrates the dermis layer effectively, which promotes cell proliferation, tissue granulation, angiogenesis, and tissue remodeling. Consequently, the findings suggest that 30Kc19α improves the therapeutic functionalities of bFGF, and would be useful as a protein stabilizer and/or a delivery vehicle in therapeutic applications.

Facilitated Transdermal Drug Delivery Using Nanocarriers-Embedded Electroconductive Hydrogel Coupled with Reverse Electrodialysis-Driven Iontophoresis.

We herein developed an iontophoretic transdermal drug delivery system for the effective delivery of electrically mobile drug nanocarriers (DNs). Our system consists of a portable and disposable reverse electrodialysis (RED) battery that generates electric power for iontophoresis through the ionic exchange. In addition, in order to provide a drug reservoir to the RED-driven iontophoretic system, an electroconductive hydrogel composed of polypyrrole-incorporated poly(vinyl alcohol) (PYP) was used. The PYP hydrogel facilitated electron transfer from the RED battery and accelerated the mobility of electrically mobile DNs released from the PYP hydrogel. In this study, we showed that fluconazole- or rosiglitazone-loaded DNs could be functionalized with charge-inducing agents, and DNs with charge modification resulted in facilitated transdermal transport via repulsive RED-driven iontophoresis. In addition, topical application and RED-driven iontophoresis of rosiglitazone-loaded DNs resulted in an effective antiobese condition displaying decreased bodyweight, reduced glucose level, and increased conversion of white adipose tissues to brown adipose tissues in vivo. Consequently, we highlight that this transdermal drug delivery platform would be extensively utilized for delivering diverse therapeutic agents in a noninvasive way.