Skin diseases are the fourth leading cause of nonfatal and chronic skin diseases, acting as a global burden and affecting the world economy. Skin diseases severely impact the patients' quality of life and have influenced their physical and mental state. Treatment of these skin disorders with conventional methods shows a lack of therapeutic efficacy, long treatment duration, recurrence of the condition, and systemic side effects due to improper drug delivery. However, these pitfalls can be overcome with the applications of advanced nanocarrier- and microneedle (MN)-based transdermal drug delivery strategies that provide efficient site-specific drug delivery at the target site. These advanced transdermal drug delivery strategies can be more effective than other drug administration routes by avoiding first-pass metabolism, enhancing the drug concentration in local skin lesions, and reducing systemic toxicity. Compared with traditional transdermal delivery methods, nanocarrier- or MN-based drug delivery systems are painless, noninvasive, or minimum-invasive and require no expensive equipment. More importantly, they can introduce more advanced functions, including increased skin penetration efficiency, controlled drug release rates, enhanced targeting abilities, and theranostic functions. Here, the emergence of versatile advanced transdermal drug delivery systems for the transdermal delivery of various drugs is reviewed, focusing on the design principles, advantages, and considerations of nanocarrier- and MN-based transdermal drug delivery strategies and their applications in treating diverse skin diseases, including psoriasis, dermatitis, melanoma, and other skin diseases. Moreover, the prospects and challenges of advanced transdermal delivery strategies for treating dermatological disorders are summarized.

The research on advanced functional polymers is being driven by the fast-growing demand for new functional materials that can be used in revolutionary technologies. Polymers can be endowed with functions by using certain special preparation methods or by introducing functional groups or fillers into materials. These functions are either intrinsically possessed by materials or actuated by external stimuli. In this review, we present an overview of the recent developments made in the research hotspots of functional polymers, encompassing polymerization methodologies, luminescent polymers, photovoltaic polymers, other electronic and optical polymers (including low-k polyimides and second-order nonlinear optical polymers), biorelated polymers (particularly those for biomedical applications), supramolecular polymers, stimuli-responsive polymers, shape-memory polymers, separation polymer membranes, energy storage polymers, and covalent organic framework polymers. The concepts, design strategies at the molecular level, preparation methods, classifications, properties, potential applications, and recent progress made in such polymers are summarized. Challenges and future perspectives of each type of functional polymers are also addressed, including research efforts regarding the design and fabrication of functional polymers for serving the increasing demand for new materials.

Wound management is a crucial measure for skin wound healing and is significantly important to maintaining the integrity of skins and their functions. Electrical stimulation at the wound site is a compelling strategy for skin wound repair. However, there has been an urgent need for wearable and point-of-care electrical stimulation devices that have self-adhesive and mechanical properties comparable to wound tissue. Herein, we develop a bioinspired hybrid patch with self-adhesive and piezoelectric nanogenerator (HPSP) for promoting skin wound healing, which is composed of a mussel-inspired hydrogel matrix and a piezoelectric nanogenerator based on aligned electrospun poly(vinylidene fluoride) nanofibers. The device with optimized modulus and permeability for skin wear can self-adhere to the wound site and locally produce a dynamic voltage caused by motion. We show that the HPSP not only promotes fibroblast proliferation and migration in vitro, but also effectively facilitates the collagen deposition, angiogenesis, and re-epithelialization in vivo with the increased expressions of crucial growth factors. The HPSP reduces the wound closure time of full-thickness skin defects by about 1/3, greatly accelerating the healing process. This patch can serve as wearable and real-time electrical stimulation devices, potentially useful in clinical applications of skin wound healing.