Organic-Hydrochloride-Modified ZnO Electron Transport Layer for Efficient Defect Passivation and Stress Release in Rigid and Flexible all Inorganic Perovskite Solar Cells.

All inorganic CsPbI2Br perovskite (AIP) has attracted great attention due to its excellent resistance against thermal stress as well as the remarkable capability to deliver high-voltage output. However, CsPbI2Br perovskite solar cells (PeSCs) still encounter critical challenges in attaining both high efficiency and mechanical stability for commercial applications. In this work, formamidine disulfide dihydrochloride (FADD) modified ZnO electron transport layer (ETL) has been developed for fabricating inverted devices on either rigid or flexible substrate. It is found that the FADD modification leads to efficient defects passivation, thereby significantly reducing charge recombination at the AIP/ETL interface. As a result, rigid PeSCs (r-PeSCs) deliver an enhanced efficiency of 16.05% and improved long-term thermal stability. Moreover, the introduced FADD can regulate the Young's modulus (or Derjaguin-Muller-Toporov (DMT) modilus) of ZnO ETL and dissipate stress concentration at the AIP/ETL interface, effectively restraining the crack generation and improving the mechanical stability of PeSCs. The flexible PeSCs (f-PeSCs) exhibit one of the best performances so far reported with excellent stability against 6000 bending cycles at a curvature radius of 5 mm. This work thus provides an effective strategy to simultaneously improve the photovoltaic performance and mechanical stability.

Exosome inspired photo-triggered gelation hydrogel composite on modulating immune pathogenesis for treating rheumatoid arthritis.

Although exosome therapy has been recognized as a promising strategy in the treatment of rheumatoid arthritis (RA), sustained modulation on RA specific pathogenesis and desirable protective effects for attenuating joint destruction still remain challenges. Here, silk fibroin hydrogel encapsulated with olfactory ecto-mesenchymal stem cell-derived exosomes (Exos@SFMA) was photo-crosslinked in situ to yield long-lasting therapeutic effect on modulating the immune microenvironment in RA. This in situ hydrogel system exhibited flexible mechanical properties and excellent biocompatibility for protecting tissue surfaces in joint. Moreover, the promising PD-L1 expression was identified on the exosomes, which potently suppressed Tfh cell polarization via inhibiting the PI3K/AKT pathway. Importantly, Exos@SFMA effectively relieved synovial inflammation and joint destruction by significantly reducing T follicular helper (Tfh) cell response and further suppressing the differentiation of germinal center (GC) B cells into plasma cells. Taken together, this exosome enhanced silk fibroin hydrogel provides an effective strategy for the treatment of RA and other autoimmune diseases.

Chitosan Lactate Particles for Non-Compression Hemostasis on Hepatic Resection.

The liver is the most complex vascular anatomy of all human organs, with extremely rich blood flow and fragile texture. Massive liver bleeding usually occurs after traumatic liver injury, causing severe systematic issues. Thus, bleeding control is critical in hindering mortality rates and complications in patients. In this study, non-compression hemostasis materials based on chitosan lactate particles (CLP) were developed for handling liver bleeding after injuries. CLP showed good blood biocompatibility and antibacterial performance against S. aureus. Taking advantage of the vital capacity of CLP to promote red blood cell and platelet adhesion, CLP exhibited in vivo homeostasis properties as non-compression hemostasis materials for traumatic liver injury, both in SD rats, New Zealand rabbits, or in beagles. Whereas CLP has better hemostasis than the commercial hemostatic agent Celox™.

Progress in methods for evaluating Schwann cell myelination and axonal growth in peripheral nerve regeneration via scaffolds.

Peripheral nerve injury (PNI) is a neurological disorder caused by trauma that is frequently induced by accidents, war, and surgical complications, which is of global significance. The severity of the injury determines the potential for lifelong disability in patients. Artificial nerve scaffolds have been investigated as a powerful tool for promoting optimal regeneration of nerve defects. Over the past few decades, bionic scaffolds have been successfully developed to provide guidance and biological cues to facilitate Schwann cell myelination and orientated axonal growth. Numerous assessment techniques have been employed to investigate the therapeutic efficacy of nerve scaffolds in promoting the growth of Schwann cells and axons upon the bioactivities of distinct scaffolds, which have encouraged a greater understanding of the biological mechanisms involved in peripheral nerve development and regeneration. However, it is still difficult to compare the results from different labs due to the diversity of protocols and the availability of innovative technologies when evaluating the effectiveness of novel artificial scaffolds. Meanwhile, due to the complicated process of peripheral nerve regeneration, several evaluation methods are usually combined in studies on peripheral nerve repair. Herein, we have provided an overview of the evaluation methods used to study the outcomes of scaffold-based therapies for PNI in experimental animal models and especially focus on Schwann cell functions and axonal growth within the regenerated nerve.

Protective effect of hydroxysafflor yellow A on renal ischemia­-reperfusion injury by targeting the Akt­Nrf2 axis in mice.

Ischemic/reperfusion (I/R) injury is the primary cause of acute kidney injury (AKI). Hydroxysafflor yellow A (HSYA), a natural compound isolated from Carthamus tinctorius L., has been found to possess anti-inflammatory and antioxidant properties. However, the protective effects and potential mechanism of HSYA on I/R-induced AKI remains unclear. In the present study, the in vitro hypoxia/reoxygenation (H/R) and in vivo renal I/R models were employed to investigate the renal protective effects and molecular mechanisms of HSYA on I/R-induced AKI. The present results indicated that HSYA pretreatment significantly ameliorated renal damage and dysfunction in the I/R injury mice via enhancing the antioxidant capacity and suppressing the oxidative stress injury, inflammatory response, and apoptosis. Mechanistic studies showed that HSYA could upregulate Akt/GSK-3ß/Fyn-Nrf2 axis-mediated antioxidant gene expression both in vitro and in vivo. Moreover, HSYA-mediated improvement in antioxidant, anti-inflammatory, and anti-apoptotic effects in H/R-treated HK-2 cells was abrogated by Akt inhibitor LY294002 supplementation. In summary, the present results demonstrated that HSYA attenuated kidney oxidative stress, inflammation response, and apoptosis induced by I/R, at least in part, via activating the Akt/GSK-3ß/Fyn-Nrf2 axis pathway. These findings provided evidence that HSYA may be applied as a potential therapeutic agent in the treatment of I/R induced AKI.

The success of biomaterial-based tissue engineering strategies for peripheral nerve regeneration.

Peripheral nerve injury is a clinically common injury that causes sensory dysfunction and locomotor system degeneration, which seriously affects the quality of the patients' daily life. Long gapped defects in large nerve are difficult to repair via surgery and limited donor source of autologous nerve greatly challenges the successful nerve repair by transplantation. Significantly, remarkable progress has been made in repairing the peripheral nerve injury using artificial nerve grafts and a variety of products for peripheral nerve repair have emerged been approved globally in recent years. The raw materials of these commercial products includes natural/synthetic polymers, extracellular matrix. Despite a lot of effort, the desirable functional recovery still remains great challenges in long gapped nerve defects. Thus this review discusses the recent development of tissue engineering products for peripheral nerve repair and the design of bionic grafts improving the local microenvironment for accelerating nerve regeneration against locomotor disorder, which may provide potential strategies for the repair of long gaps or thick nerve defects by multifunctional biomaterials.

Regenerative Role of T Cells in Nerve Repair and Functional Recovery.

The immune system is essential in the process of nerve repair after injury. Successful modulation of the immune response is regarded as an effective approach to improving treatment outcomes. T cells play an important role in the immune response of the nervous system, and their beneficial roles in promoting regeneration have been increasingly recognized. However, the diversity of T-cell subsets also delivers both neuroprotective and neurodegenerative functions. Therefore, this review mainly discusses the beneficial impact of T-cell subsets in the repair of both peripheral nervous system and central nervous system injuries and introduces studies on various therapies based on T-cell regulation. Further discoveries in T-cell mechanisms and multifunctional biomaterials will provide novel strategies for nerve regeneration.

Silk-inspired fiber implant with multi-cues enhanced bionic microenvironment for promoting peripheral nerve repair.

Successful repair and desirable functional recovery of large-gap nerve injuries using artificial nerve implants remains a significant clinical challenge. The beneficial bionic microenvironment within scaffolds can significantly promote the outgrowth of newborn nerve tissues after implantation. Herein, we developed an aligned silk-inspired fiber scaffold (RGD@ASFFs) with a synergistic effect of an extracellular matrix mimicking physical cues and RGD (Arg-Gly-Asp) signals to provide an enhanced cell-friendly microenvironment for repairing large-gap peripheral nerve injuries. The topographic alignment of the methacrylated silk fibroin electrospun fibers effectively facilitated axonal guidance and oriented Schwann cell growth. Importantly, the mechanical cue combined with cell adhesion signals provided by RGD peptides further triggered enriched myelination of Schwann cells by nuclear translocation of Yes-associated protein 1 (YAP) to secrete neurotrophins to support axonal growth. Moreover, benefiting from improved neuronal extension and re-myelination, promising motor function recovery in vivo was achieved by RGD@ASFFs, which is comparable to that of autografts. Thus, the design of this engineered bionic scaffold is a powerful strategy for peripheral nerve defect repair.

Managing Defects Density and Interfacial Strain via Underlayer Engineering for Inverted CsPbI2 Br Perovskite Solar Cells with All-Layer Dopant-Free.

Inorganic perovskite CsPbI2 Br has advantages of excellent thermal stability and reasonable bandgap, which make it suitable for top layer of tandem solar cells. Nevertheless, solution-processed all-inorganic perovskites generally suffer from high-density defects as well as significant tensile strain near underlayer/perovskite interface, both leading to compromised device efficiency and stability. In this work, the defect density as well as interfacial tensile strain in inverted CsPbI2 Br perovskite solar cells (PeSCs) is remarkably reduced by using a bilayer underlayer composed of dopant-free 2,2',7,7'-tetrakis(N,N-dip-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD) and copper phthalocyanine 3,4',4″,4'″-tetrasulfonated acid tetrasodium salt (TS-CuPc) nanoparticles. As compared to control devices with pristine Spiro-OMeTAD, devices based on Spiro-OMeTAD/TS-CuPc exhibit remarkably improved photovoltaic performance and enhanced thermal/humidity stability due to the better perovskite crystallization, improved interfacial passivation, and hole-collection as well as efficient interfacial strain release. As a result, a champion efficiency of 14.85% can be achieved, which is approaching to the best reported for dopant-free and inverted all-inorganic PeSCs. The work thus provides an efficient strategy to simultaneously regulate the defects density and strain issue related to inorganic perovskites.

Self-Propelled and Electrobraking Synergetic Liquid Manipulator toward Microsampling and Bioanalysis.

Droplet manipulation is of paramount significance for microfluidics-based biochips, especially for bioanalytical chips. Despite great progresses made on droplet manipulation, the existing bioanalytical methods face challenges in terms of capturing minute doses toward hard-to-obtain samples and analyzing biological samples at low temperatures immediately. To circumvent these limitations, a self-propelled and electric stimuli synergetic droplet manipulator (SES-SDM) was developed by a femtosecond laser microfabrication strategy followed by post-treatment. Combining the inspiration from cactus and Nepenthes pitcher plants, the wedge structure with the microbowl array and silicone oil infusion was endowed cooperatively with the SES-SDM. With the synergy of the ultralow voltage (4.0 V) stimuli, these bioinspired features enable the SES-SDM to transport the droplet spontaneously and controllably, showing the maximum fast motion (15.7 mm/s) and long distance (96.2 mm). Remarkably, the SES-SDM can function at -5 °C without the freezing of the droplets, where the self-propelled motion and electric-responsive pinning can realize the accurate capture and real-time analysis of the microdroplets of the tested samples. More importantly, the SES-SDM can realize real-time diagnosis of excessive heavy metal in water by the cooperation of self-propulsion and electro-brake. This work opens an avenue to design a microsampling (5-20 µL) manipulator toward producing the minute samples for efficient bioanalysis and offers a strategy for microanalysis using the synergistic droplet manipulation.

Anisotropic Silk-Inspired Nerve Conduit with Peptides Improved the Microenvironment for Long-Distance Peripheral Nerve Regeneration.

A lack of effective bioactivity to create a desirable microenvironment for peripheral nerve regeneration has been challenging in successful treatment of long-distance injuries using nerve guidance conduits (NGCs) clinically. Herein, we developed a silk-inspired phototriggered gelation system combining dual therapeutic cues of anisotropic topography and adhesive ligands for improving peripheral nerve regeneration. Importantly, enhanced cell recruitment and myelination of Schwann cells were successfully achieved by the Arg-Gly-Asp (RGD)-peptide-immobilized hydrogel scaffolds to promote axon growth. Moreover, as the orientated growth of Schwann cells and rapid axon growth were facilitated by aligned grooved micropatterns, this multifunctional bioactive system provides remarkable nerve regeneration with function recovery for long-distance nerve injury. Therefore, this bioengineered silk-inspired nerve guidance conduit delivers a platform for desirable peripheral nerve repair.

Light-Triggered Adhesive Silk-Based Film for Effective Photodynamic Antibacterial Therapy and Rapid Hemostasis.

Successful control of massive hemorrhage in deep wounds with irregular shape and low elasticity still remains great challenges in the clinic. As the wound sites are usually at risk of bacterial infection, it is necessary to design an ideal hemostatic agent with rapid hemostasis and excellent antibacterial activity. In this study, we developed a light responsive hemostatic film for effective handling of liver bleeding with promising photodynamic therapy against S. aureus onnear infrared (NIR) irradiation. Based on silk fibroin, the film exhibited desirable biocompatibility and mechanical property as a hemostat tape. Significantly, the film tape achieved excellent tissue adhesion and hemostasis in vivo within 2 min of UV exposure, which would have a great potential as a multifunctional biomedical material in the field of tissue repair such as wound healing, bone repair, and nerve regeneration.

Stable antibacterial polysaccharide-based hydrogels as tissue adhesives for wound healing.

Adhesion to the surface of moist, dynamic, biological tissues is important in many fields. Currently, tissue adhesives commonly used in clinical practice remain far from ideal, exhibiting either poor tissue compatibility or weak tissue adhesion. Here, we designed biocompatible hydrogels comprising polysaccharides with polyacrylamide and exhibiting promising cytocompatibility, antibacterial activity, and excellent tissue adhesion. Alginate/chitosan-based hydrogels covalently cross-linked to the tissue surface in order to achieve admirable tissue adhesion. Additionally, the mechanical properties of the hydrogels were significantly enhanced with the addition of polyacrylamide, which synergistically promoted their enhanced adhesion. Importantly, the hydrogels exhibited good biocompatibility and reasonable antibacterial activity that promoted wound recovery during use as wound dressings. These results suggested the efficacy of the developed tissue adhesives for applications in biomedical fields, as well as broadening potential hydrogel use in tissue engineering.

Freestanding Hyaluronic Acid/Silk-Based Self-healing Coating toward Tissue Repair with Antibacterial Surface.

Developing coatings with multifunctional and biocompatible properties to enhance tissue wound regeneration is preferably applied clinically. Consequently, the freestanding and self-healing coatings were formed with the employment of the layer-by-layer (LbL) self-assembly. The coatings comprise beta-cyclodextrin-modified silk fibroin (SCD) and adamantane-modified hyaluronic acid (HAD) on the basis of the interactions between the host and the guest. The self-healing and freestanding capabilities allow the coatings to easily and repeatedly repair external mechanical damage and could be pulled off substrate. More importantly, the coatings have admirable antibacterial activity and biocompatibility. Moreover, the proliferation of cells and the myelination of Schwann cells are enhanced. Thus, we believe that the multifunctional coatings will have great potential in tissue engineering, especially for nerve regeneration.

Low-Frequency Pulsed Magnetic Field Improves Depression-Like Behaviors and Cognitive Impairments in Depressive Rats Mainly via Modulating Synaptic Function.

Transcranial magnetic stimulation (TMS) has shown great promise as a medical treatment of depression. The effectiveness of TMS treatment at high frequency has been well investigated; however, low-frequency TMS in depression treatment has rarely been investigated in depression-induced cognitive deficits. Herein, this study was carried out to assess the possible modulatory role of low-frequency pulsed magnetic field (LFPMF) on reversing cognitive impairment in a model of depression induced by chronic unpredictable stress (CUS). Wistar rats were randomly allocated into four groups as follows: a control group (CON), a control applied with LFPMF (CON + LFPMF), a CUS group, and a CUS treated with LFPMF (CUS + LFPMF) group. During 8 weeks of CUS, compared to those in the CON group, animals not only gained less weight but also exhibited anhedonia, anxiety, and cognitive decline in behavioral tests. After 2-week treatment of LFPMF, a 20 mT, 1 Hz magnetic stimulation, it reversed the impairment of spatial cognition as well as hippocampal synaptic function including long-term potentiation and related protein expression. Thus, LFPMF has shown effectively improvements on depressant behavior and cognitive dysfunction in CUS rats, possibly via regulating synaptic function.