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Diabetic wounds that do not heal for a long time challenge global healthcare. Mesenchymal stem cell (MSC) therapy has positive significance in promoting diabetic wound healing. However, traditional MSC therapy involves exogenous MSCs, which brings many limitations and unsatisfactory treatment. Moreover, the maintenance of MSC viability and function is difficult because of the high level of reactive oxygen species (ROS) in diabetic wounds. Therefore, we developed a nanofibrous dressing to recruit and protect endogenous MSCs while avoiding the inherent disadvantages of exogenous MSCs. Ceria nanoparticles capable of ROS scavenging are integrated into the nanofibrous dressings, together with Apt19S, a DNA aptamer with affinity and selectivity for MSCs. In addition, the homogenization and freeze-drying technology give the nanofibrous dressings good elasticity, which protects the wound from external pressure. Further experiments in diabetic mice show that the dressing has excellent endogenous MSC recruitment and anti-inflammatory properties, thereby synergistically promoting diabetic wound healing. This study is expected to explore an efficient method of stem cell therapy, providing a new way to construct high-performance wound dressings.

It is widely accepted that a small particle size and rough surface can enhance tumor tissue accumulation and tumor cellular uptake of nanoparticles, respectively. Herein, sub-50 nm urchin-inspired disulfide bond-bridged mesoporous organosilica nanoparticles (UMONs) featured with a spiky surface and glutathione (GSH)-responsive biodegradability were successfully synthesized by a facile one-pot biphasic synthesis strategy for enhanced cellular internalization and tumor accumulation. l-Arginine (LA) is encapsulated into the mesopores of UMONs, whose outer surface is capped with the gatekeeper of ultrasmall gold nanoparticles, i.e., UMONs–LA–Au. On the one hand, the mild acidity-activated uncapping of ultrasmall gold can realize a tumor microenvironment (TME)-responsive release of LA. On the other hand, the unique natural glucose oxidase (GOx)-mimicking catalytic activity of ultrasmall gold can catalyze the decomposition of intratumoral glucose to produce acidic hydrogen peroxide (H2O2) and gluconic acid. Remarkably, these products can not only further facilitate the release of LA, but also catalyze the LA–H2O2reaction for an increased nitric oxide (NO) yield, which realizes synergistic catalysis-enhanced NO gas therapy for tumor eradication. The judiciously fabricated UMONs–LA–Au present a paradigm of TME-responsive nanoplatforms for both enhanced cellular uptake and tumor-specific precision cascaded therapy, which broadens the range of practical biomedical applications and holds a significant promise for the clinical translation of silica-based nanotheranostics.

Multicellular spheroids can mimic the in vivo microenvironment and maintain the unique functions of tissues, which has attracted great attention in tissue engineering. However, the traditional culture microenvironment with structural deficiencies complicates the culture and collection process and tends to lose the function of multicellular spheroids with the increase of cell passage. In order to construct efficient and functional multicellular spheroids, in this study, a chitosan/polyvinyl alcohol nanofiber sponge which has an open-cell cellular structure is obtained. The hair follicle (HF) regeneration model was employed to evaluate HF-inducing ability of dermal papilla (DP) multicellular spheroids which formed on the cellular structure nanofiber sponge. Through structural fine-tuning, the nanofiber sponge has appropriate elasticity for the creation of a three-dimensional dynamic microenvironment to regulate cellular behavior. The cellular structure nanofiber sponge tilts the balance of cell–substratum and cell–cell interactions to a state which is more conducive to the formation of controllable multicellular spheroids in a short time. More importantly, it improves the secretory activity of high-passaged dermal papilla cells and restores their intrinsic properties. Experiments using BALB/c nude mice show that cultured DP multicellular spheroids could effectively enhance HF-inducing ability. This novel system provides a simple and efficient strategy for multicellular spheroid formation and HF regeneration.

Cartilage repair has been a significant challenge in orthopedics that has not yet been fully resolved. Due to the absence of blood vessels and the almost cell-free nature of mature cartilage tissue, the limited ability to repair cartilage has resulted in significant socioeconomic pressures. Polysaccharide materials have recently been widely used for cartilage tissue repair due to their excellent cell loading, biocompatibility, and chemical modifiability. They also provide a suitable microenvironment for cartilage repair and regeneration. In this Review, we summarize the techniques used clinically for cartilage repair, focusing on polysaccharides, polysaccharides for cartilage repair, and the differences between these and other materials. In addition, we summarize the techniques of tissue engineering strategies for cartilage repair and provide an outlook on developing next-generation cartilage repair and regeneration materials from polysaccharides. This Review will provide theoretical guidance for developing polysaccharide-based cartilage repair and regeneration materials with clinical applications for cartilage tissue repair and regeneration.

Delayed and nonhealing of diabetic wounds imposes substantial economic burdens and physical pain on patients. Mesenchymal stem cells (MSCs) promote diabetic wound healing. Particularly when MSCs aggregate into multicellular spheroids, their therapeutic effect is enhanced. However, traditional culture platforms are inadequate for the efficient preparation and delivery of MSC spheroids, resulting in inefficiencies and inconveniences in MSC spheroid therapy. In this study, a three-dimensional porous nanofibrous dressing (NFD) is prepared using a combination of electrospinning and homogeneous freeze-drying. Using thermal crosslinking, the NFD not only achieves satisfactory elasticity but also maintains notable cytocompatibility. Through the design of its structure and chemical composition, the NFD allows MSCs to spontaneously form MSC spheroids with controllable sizes, serving as MSC spheroid delivery systems for diabetic wound sites. Most importantly, MSC spheroids cultured on the NFD exhibit improved secretion of vascular endothelial growth factor, basic fibroblast growth factor, and hepatocyte growth factor, thereby accelerating diabetic wound healing. The NFD provides a competitive strategy for MSC spheroid formation and delivery to promote diabetic wound healing.

The application of the nanofiber film in the field of food preservation was an emerging research direction in recent years. With the functionalization of nanofibers, the quality and safety of food can be better guaranteed. In the present work, thymol as an antibacterial agent was encapsulated into poly(lactide-co-glycolide) to form core–shell nanofibers by coaxial electrospinning. With such a core–shell nanofiber film, thymol can be slowly released to headspace between food and the nanofiber film, inhibiting the growth of bacteria on the surface of food. The morphology and core–shell structure of nanofibers were confirmed by scanning electron microscopy and transmission electron microscopy. The antibacterial and fruit preservation abilities of the nanofiber film were tested on strawberries. Studies have shown that it can effectively inhibit the growth of bacteria, fungi, and yeast and extend the shelf life of fruit. This novel antibacterial packaging material with excellent biocompatibility, biodegradability, and good sustained release performance would have a broad application prospect in the field of food preservation.

A dual function system that inhibits tumor growth while promoting wound healing is very necessary for melanoma treatment since tumor killing and skin healing are two complementary and influential processes. Herein, a controllable local drug delivery system based on porous fiber membranes incorporated with CuS nanoparticles is designed for chemo-photothermal synergistic melanoma therapy and promoting wound healing. The porous structure on the fiber surface significantly increases the drug loading capacity of the membrane and the photothermal effect of incorporated CuS nanoparticles is used to control the drug release rate. Benefitting from the chemo-photothermal synergistic therapy, the composite membrane can effectively kill melanoma cells in vitroand inhibit tumor growth in vivo. Furthermore, the membrane can also significantly promote the cutaneous wound healing by providing mechanical support and releasing copper ions. Thus, this work provides new ideas for the development of multifunctional local treatment and postoperative care systems.

Gene interference-based therapeutics represent a fascinating challenge and show enormous potential for cancer treatment, in which microRNA is used to correct abnormal gene. On the basis of the above, we introduced microRNA-31 to bind to 3′-untranslated region of mtEF4, resulting in the downregulation of its messenger RNA and protein to trigger cancer cells apoptosis through mitochondria-related pathway. To achieve better therapeutic effect, a mesoporous silica nanoparticle-based controlled nanoplatform had been developed. This system was fabricated by conjugation of microRNA-31 onto doxorubicin-loaded mesoporous silica nanoparticles with a poly(ethyleneimine)/hyaluronic acid coating, and drug release was triggered by acidic environment of tumors. By feat of surface functionalization and tumor-specific conjugation to nanoparticles, our drug delivery system could promote intracellular accumulation of drugs via the active transport at tumor site. More importantly, microRNA-31 not only directly targeted to mtEF4 to promote cell’s death, but had synergistic effects when used in combination with doxorubicin, and achieved excellent superadditive effects. As such, our research might provide new insights toward detecting high mtEF4 cancer and exploiting highly effective anticancer drugs.

Herein, voltage-responsive controlled release film was constructed by grafting ferrocene on the mesoporous inverse opal photonic crystal (mIOPC). The film achieved free-blockage controlled release and realized the monitoring of cargo release without external indicator. Free-blockage was attributed to the voltage switchable nanovalves which undergo hydrophobic-to-hydrophilic transition when applying voltage. Monitoring of cargo release was attributed to the optical property of mIOPC, the bandgap of mIOPC had a red shift when the solution invaded in. The film was hydrophobic enough to stop solution intrusion. Once the voltage was applied, the film became hydrophilic, leading to invasion of the solution. As a result, the cargos were released and the bandgap of mIOPC was red-shifted. Therefore, in this paper both a free-blockage controlled release film and a release sensing system was prepared. The study provides new insights into highly effective controlled release and release sensing without indicator.

In this paper, for a vertex operator algebra Vwith an automorphism gof order T, an admissible V-module Mand a fixed nonnegative rational number $$n \in \tfrac{1} {T}\mathbb{Z}_ +$$, we construct an Ag,n(V)-bimodule Ag,n(M) and study its properties, discuss the connections between bimodule Ag,n(M) and intertwining operators. Especially, bimodule $$A_{g,n - \tfrac{1} {T}} (M)$$(M) is a natural quotient of Ag,n(M) and there is a linear isomorphism between the space $$\mathcal{I}_{M M^j }^{M^k }$$of intertwining operators and the space of homomorphisms $$Hom_{A_{g,n} (V)} \left( {A_{g,n} \left( M \right) \otimes _{A_{g,n} (V)} M^j \left( s \right),M^k \left( t \right)} \right)$$for s, t⩽ n, Mj, Mkare g-twisted Vmodules, if Vis g-rational.