Transepidermal drug delivery achieves high drug concentrations at the action site and ensures continuous drug delivery and better patient compliance with fewer adverse effects. However, drug delivery through topical application is still limited in terms of drug penetration. Chitosan is a promising enhancer to overcome this constraint, as it can enhance drug diffusion by opening the tight junctions of the stratum corneum. Therefore, here, we developed a novel chitosan nanosponge (CNS) with an optimal ratio and molecular weight of chitosan to improve drug penetration through skin. To prepare the CNS, two types of chitosan (3 and 10 kDa) were each conjugated with poloxamer 407 using para-nitrophenyl chloroformate, and the products were mixed with poloxamer 407 at ratios of 5:5, 8:2, and 10:0. The resulting mixtures were molded to produce flexible soft nanosponges by simple nanoprecipitation. The CNSs were highly stable in biological buffer for four weeks and showed no toxicity in human dermal fibroblasts. The CNSs increased drug permeability through human cadaver skin in a Franz-type diffusion cell, with substantially higher permeability with 3 kDa chitosan at a ratio of 8:2. This suggests the applicability of the novel CNS as a promising carrier for efficient transepidermal drug delivery.

Prussian blue (PB) is a metal cluster nanoparticle (NP) of cyanide-bridged iron(II)–iron(III) and exhibits a characteristic blue color. Its peroxidase-, catalase-, and superoxide-dismutase-like activities effectively remove excess reactive oxygen species that induce inflammation and tumorigenesis. However, the dispersion of PB NPs is not sufficiently stable for their application in the biomedical field. In this study, we developed Pluronic-stabilized Prussian blue nanoparticles (PB/Plu NPs) using a series of Pluronic triblock copolymers as a template material for PB NPs. Considering the hydrophilic–lipophilic balance (HLB) values of the Pluronic series, including F68, F127, L35, P123, and L81, the diameters of the PB/Plu NPs decreased from 294 to 112 nm with decreasing HLB values. The smallest PB NP stabilized with Pluronic P123 (PB/PP123 NP) showed the strongest antioxidant and anti-inflammatory activities and wound-healing efficacy because of its large surface area. These results indicated that the spatial distribution of PB NPs in the micelles of Pluronic greatly improved the stability and reactive oxygen species scavenging activity of these NPs. Therefore, PB/Plu NPs using U.S.-FDA-approved Pluronic polymers show potential as biocompatible materials for various biomedical applications, including the treatment of inflammatory diseases in the clinic.

Retinyl palmitate (RP) is a retinol ester with strong antioxidant and anti-inflammatory properties as an antiwrinkle agent. However, it has poor aqueous solubility and easily degrades into inactive forms for topical applications. Therefore, we developed chitosan-coated nanocapsules (ChiNCs) to encapsulate RP using a simple nanoprecipitation method for protection against physiological conditions and to enable deep skin penetration. The as-prepared RP-loaded nanocapsules (RP@ChiNCs) loaded with approximately 5 wt.% RP exhibited a hydrodynamic diameter of 86 nm and surface charge of 24 mV. They had adequate stability to maintain their physicochemical properties after lyophilization in a biological buffer. Notably, ChiNCs provided RP with remarkable protection against degradation for 4 weeks at 37 °C. Thus, RP@ChiNCs exhibited good antioxidant activity in situ for sufficiently long periods without considerable changes in their efficacy. Furthermore, ChiNCs enhanced the skin penetration of lipophilic RP based on the inherent nature of chitosan. RP@ChiNCs exhibited good in vitro antioxidant and anti-inflammatory effects without causing any cytotoxicity in dermal fibroblasts. Accordingly, they promoted cell proliferation in a wound-scratch test and enhanced collagen synthesis. These results suggest that RP@ChiNCs are promising candidates for cosmetic and biomedical applications.

Cancer, which is a leading cause of death, contributes significantly to reducing life expectancy worldwide. Even though paclitaxel (PTX) is known as one of the main anticancer drugs, it has several limitations, including low solubility in aqueous solutions, a limited dosage range, an insufficient release amount, and patient resistance. To overcome these limitations, we suggest the development of PTX-loaded thermosponge nanoparticles (PTX@TNP), which result in improved anticancer effects, via a simple nanoprecipitation method, which allows the preparation of PTX@TNPs with hydrophobic interactions without any chemical conjugation. Further, to improve the drug content and yield of the prepared complex, the co-organic solvent ratio was optimized. Thus, it was observed that the drug release rate increased as the drug capacity of PTX@TNPs increased. Furthermore, increasing PTX loading led to considerable anticancer activity against multidrug resistance (MDR)-related colorectal cancer cells (HCT 15), implying a synergistic anticancer effect. These results suggest that the solubilization of high drug amounts and the controlled release of poorly water-soluble PTX using TNPs could significantly improve its anticancer therapy, particularly in the treatment of MDR-p-glycoprotein-overexpressing cancers.

Illite is a clay mineral that shows antioxidant and antibacterial activities because of the abundance of important clay elements in its structure. However, illite has low bioactivity due to its low solubility and electron-donating ability in aqueous solutions. Therefore, we aimed to develop polyvinylpyrrolidone (PVP)-stabilized illite microparticles (P-lite MPs) via polymer adsorption on illite surfaces. An increasing amount of PVP was used to coat a fixed amount of illite to prepare P-lite MPs of different hydrodynamic diameters in the range of 4–9 μm. These sizes were maintained for 2 weeks during storage in a biological buffer without any noticeable changes. The stabilization of illite microparticles using a hydrophilic PVP polymer improved their aqueous dispersity and free radical-scavenging activity. Since the large surface area of microparticles provides several sites for interactions, the smallest P-lite MP exhibited the highest antioxidant and antibacterial activities. More importantly, the MPs showed effective free radical-scavenging activity in vitro without any cytotoxicity. Therefore, P-lite MPs with improved bioavailability may represent a suitable bioactive material for various industrial and biomedical applications.

Mitochondrial dysfunction increases ROS production and is closely related to many degenerative cellular organelle diseases. The NOX4-p22phox axis is a major contributor to ROS production and its dysregulation is expected to disrupt mitochondrial function. However, the field lacks a competitive inhibitor of the NOX4-p22phox interaction. Here, we created a povidone micelle-based Prussian blue nanozyme that we named “Mitocelle” to target the NOX4-p22phox axis, and characterized its impact on the major degenerative cellular organelle disease, osteoarthritis (OA). Mitocelle is composed of FDA-approved and biocompatible materials, has a regular spherical shape, and is approximately 88 nm in diameter. Mitocelle competitively inhibits the NOX4-p22phox interaction, and its uptake by chondrocytes can protect against mitochondrial malfunction. Upon intra-articular injection to an OA mouse model, Mitocelle shows long-term stability, effective uptake into the cartilage matrix, and the ability to attenuate joint degradation. Collectively, our findings suggest that Mitocelle, which functions as a competitive inhibitor of NOX4-p22phox, may be suitable for translational research as a therapeutic for OA and cellular organelle diseases related to dysfunctional mitochondria.