The
abuse of antibiotics induces the emergence of drug-resistant
bacteria, which greatly increases the difficulty of clinical treatment
of infected wounds. It is urgent to design a multifunctional wound
dressing independent of antibiotics. In this work, we designed multifunctional
hydrogels based on lignin and cellulose in natural polymers. Lignin
with antioxidant properties could reduce silver nanoparticles in situ and could also be used as a crosslinking agent to
construct hydrogels between hydroxypropyl cellulose modified with
phenylboric acid by a dynamic borate bond. Hydrogels have excellent
properties such as self-healing, shape adaptability, biocompatibility,
blood compatibility, antioxidant properties, excellent broad-spectrum
antimicrobial properties, good tissue adhesion, and electrical conductivity.
The tissue adhesion of hydrogels endows them with an excellent hemostasis
property in a rat liver injury model. In vivo experiments
demonstrated that hydrogels can maintain a moist healing environment,
reduce inflammatory cell infiltration, promote M2 macrophage polarization,
accelerate collagen deposition, promote the regeneration of new blood
vessels, and significantly speed up the wound healing of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds. Therefore,
these multifunctional hydrogels are an excellent candidate to treat
multiple stages of wound healing and have a broad application prospect
in the medical field.
An electroactive scaffold integrated with noninvasive in
vivo electrical-stimulation (ES) capability shows great promise
in the repair and regeneration of damaged tissues. Developing high-performance
piezoelectric biomaterials which can simultaneously serve as both
a biodegradable tissue scaffold and controllable electrical stimulator
remains a great challenge. Herein, we constructed a biodegradable
high-performance 3D piezoelectric scaffold with ultrasound (US)-driven
wireless ES capability, and demonstrated its successful application
for the repair of spinal cord injuries in a rat model. The 3D multichannel
piezoelectric scaffold was prepared by electrospinning of poly(lactic
acid) (PLA) nanofibers incorporated with biodegradable high-performance
piezoelectric potassium sodium niobate (K0.5Na0.5NbO3, KNN) nanowires. With programmed US irradiation as
a remote mechanical stimulus, the on-demand in vivo ES with an adjustable timeline, duration, and strength can be delivered
by the 3D piezoelectric scaffold. Under proper US excitation, the
3D tissue scaffolds made of the piezoelectric composite nanofibers
can accelerate the recovery of motor functions and enhance the repair
of spinal cord injury. The immunohistofluorescence investigation indicated
that the 3D piezoelectric scaffolds combined with the US-driven in vivo ES promoted neural stem cell differentiation and
endogenous angiogenesis in the lesion. This work highlights the potential
application of a biodegradable high-performance piezoelectric scaffold
providing US-driven on-demand electrical cues for regenerative medicine.
We establish a Fejér type inequality for harmonically convex functions. Our results are the generalizations of some known results. Moreover, some properties of the mappings in connection with Hermite-Hadamard and Fejér type inequalities for harmonically convex functions are also considered.
Delivering sufficient water to the evaporation surface/interface is one of the most widely adopted strategies to overcome salt accumulation in solar‐driven interfacial desalination. However, water transport and heat conduction loss are positively correlated, resulting in the trade‐off between thermal localization and salt resistance. Herein, a 3D hydrogel evaporator with vertical radiant vessels is prepared to surmount the long‐standing trade‐off, thereby achieving high‐rate and stable solar desalination of high‐salinity. Experiments and numerical simulations reveal that the unique hierarchical structure, which consists of a large vertical vessel channel, radiant vessels, and porous vessel walls, facilitates strong self‐salt‐discharge and low longitudinal thermal conductivity. With the structure employed, a groundbreaking comprehensive performance, under one sun illumination, of evaporation rate as high as 3.53 kg m−2 h−1, salinity of 20 wt%, and a continuous 8 h evaporation is achieved, which thought to be the best reported result from a salt‐free system. This work showcases the preparation method of a novel hierarchical microstructure, and also provides pivotal insights into the design of next‐generation solar evaporators of high‐efficiency and salt tolerance.
Graphene oxide-modified electrospun polyvinyl alcohol nanofibrous scaffolds exhibit good biocompatibility and have potential application in skin tissue engineering.
Peripheral nerve regeneration requires stepwise and well-organized establishment of microenvironment. Since local delivery of VEGF-A in peripheral nerve repair is expected to promote angiogenesis in the microenvironment and Schwann cells (SCs) play critical role in nerve repair, combination of VEGF and Schwann cells may lead to efficient peripheral nerve regeneration. VEGF-A overexpressing Schwann cells were established and loaded into the inner wall of hydroxyethyl cellulose/soy protein isolate/polyaniline sponge (HSPS) conduits. When HSPS is mechanically distorted, it still has high durability of strain strength, thus, can accommodate unexpected strain of nerve tissues in motion. A 10 mm nerve defect rat model was used to test the repair performance of the HSPS-SC (VEGF) conduits, meanwhile the HSPS, HSPS-SC, HSPS-VEGF conduits and autografts were worked as controls. The immunofluorescent co-staining of GFP/VEGF-A, Ki67 and MBP showed that the VEGF-A overexpressing Schwann cells could promote the proliferation, migration and differentiation of Schwann cells as the VEGF-A was secreted from the VEGF-A overexpressing Schwann cells. The nerve repair performance of the multifunctional and flexible conduits was examined though rat behavioristics, electrophysiology, nerve innervation to gastrocnemius muscle (GM), toluidine blue (TB) staining, transmission electron microscopy (TEM) and NF200/S100 double staining in the regenerated nerve. The results displayed that the effects on the repair of peripheral nerves in HSPS-SC (VEGF) group was the best among the conduits groups and closed to autografts. HSPS-SC (VEGF) group exhibited notably increased CD31
+
endothelial cells and activation of VEGFR2/ERK signaling pathway in the regenerated nerve tissues, which probably contributed to the improved nerve regeneration. Altogether, the comprehensive strategy including VEGF overexpressing Schwann cells-mediated and HSPS conduit-guided peripheral nerve repair provides a new avenue for nerve tissue engineering.
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