Flexible bidirectional self-powered photodetector with significantly reduced volume and accelerated response speed based on hydrogel and lift-off GaN-based nanowires.

Due to the wide range of potential applications for next-generation multi-functional devices, the flexible self-powered photodetector (PD) with polarity-switchable behavior is essential but very challenging to be realized. Herein, a wearable bidirectional self-powered PD based on detached (Al,Ga)N and (In,Ga)N nanowires has been proposed and demonstrated successfully. Arising from the photovoltage-competing dynamics across (Al,Ga)N and (In,Ga)N nanowire photoelectrodes, such PD can generate the positive (33.3 mA W -1) and negative (-0.019 mA W -1) photo-responsivity under ultraviolet (UV) and visible illumination, respectively, leading to the bidirectional photocurrent behavior. Thanks to the introduction of quasi solid-state hydrogel, the PD can work without the liquid-electrolyte, thus remarkably reducing the volume from about 482 cm3 to only 0.18 cm3. Furthermore, the use of hydrogel is found to enhance response speed in the UV range by reducing the response time for more than 95%, which is mainly attributed to the increased open circuit potential and reduced ion transport distance. As the GaN connecting segment is pretty thin, the piezoelectric charges generated by stress are proposed to have only a limited effect on the photocurrent density. Therefore, both the stable on-off switching characteristics and photocurrent densities can still be achieved after being bent 400 times. With an excellent flexibility, this work creates opportunities for technological applications of bidirectional photocurrent PDs in flexible optoelectronic devices, e.g., wearable intelligent sensors.

Panoramic analysis of cell death patterns reveals prognostic and immune profiles of head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) has been characterized by a low therapeutic response and poor prognosis. Currently, there are no reliable predictive models for HNSCC progression and therapeutic efficacy. This study explores the role of diverse patterns of cell death in tumor development, positing them as predictive factors of HNSCC prognosis. We utilized bulk transcriptome and single-cell transcriptome, align with clinical information from TCGA and GEO database, to analyze genes associated with 15 types of cell death and construct a cell death index (CDI) signature. The associations of CDI with tumor-infiltrating immune cells and immunotherapy-related biomarkers were also evaluated using various algorithms. The CDI signature emerged as a robust prognosis biomarker that could identify patients who can benefit potentially from immunotherapy, thus improving diagnostic accuracy and optimizing clinical decisions in HNSCC management. Notably, we discovered that CAAP1 deficiency not only induced apoptosis but also enhanced anti-tumor immunity, suggesting its potential as a target for clinical drug development.

MMP-Responsive Nanoparticle-Loaded, Injectable, Adhesive, Self-Healing Hydrogel Wound Dressing Based on Dynamic Covalent Bonds.

Developing a multifunctional hydrogel wound dressing with good injectability, self-healing, tissue adhesion, biocompatibility, and fast skin wound healing efficiency remains challenging. In this work, an injectable adhesive dopamine-functionalized oxidized hyaluronic acid/carboxymethyl chitosan/collagen (AHADA/CCS/Col) hydrogel was constructed. The Schiff dynamic bond between AHADA and CCS, the N-Ag-N bond between CCS and Ag ions, and the S-Ag-S dynamic bond between sulfhydryl-modified collagen (ColSH) and Ag ions allowed the hydrogel to be both injectable and self-healing. Moreover, the aldehyde groups and catechol groups presented in the hydrogel could generate force with several groups on the tissue interface; therefore, the hydrogel also had good tissue adhesion. In vitro experiments proved that this hydrogel exhibited good biocompatibility and could promote cell proliferation. Additionally, curcumin (Cur)-loaded gelatin nanoparticles (Cur@Gel NPs) were prepared, which could respond to matrix metalloproteinases (MMPs) and controllably release Cur to hasten wound healing efficiency. Animal experiment results showed that this AHADA/CCS/Col hydrogel loaded with Cur@Gel NPs promoted wound repairing better, indicating its potential as a wound dressing.

A mace-like heterostructural enriched injectable hydrogel composite for on-demand promotion of diabetic wound healing.

Wound healing is a multifaceted process that involves hemostasis, inflammation, proliferation, and remodeling stages. Diabetic wounds affect the transition of the organized phases and result in delayed healing due to impaired angiogenesis, chronic inflammation, bacterial infection, and insufficient growth factors. Multifunctional heterostructural nanoparticles enriched minimally invasive hydrogels for on-demand procedural distribution to aid wound healing at various stages has become a promising strategy. Herein, silk fibroin-hyaluronic acid based injectable hydrogels incorporated with mace-like Au-CuS heterostructural nanoparticles (gAu-CuS HSs) were used to cure diabetic wounds. SF-HA and the rough surface of gAu-CuS HSs confer a synergistic hemostatic phase with a nano-bridge effect and rapidly close the wounds. During the inflammation stage, gAu-CuS HSs perform in-space resonance energy transfer under 808 nm laser irradiation which in return produces reactive oxygen species for bacterial destruction. The unusual mace-like rough structure of nanoparticles causes macrophage transfer to the M2 phenotype, regulates cytokine expression (interleukin 6, transforming factor-ß1, interferon γ, and interleukin-10), promotes angiogenesis, and promotes cell multiplication and fibroblast emigration to the wound area during the proliferation and remodeling phase. Overall, the gAu-CuS HSs reinforced injectable hydrogel programmatically accelerates wound healing and could represent a versatile strategy for advanced diabetic wound healing.

Multifaceted tannin crosslinked bioinspired dECM decorated nanofibers modulating cell-scaffold biointerface for tympanic membrane perforation bioengineering.

Tympanic membrane (TM) perforation leads to persistent otitis media, conductive deafness, and affects life quality. Ointment medication may not be sufficient to treat TM perforation (TMP) due to the lack of an underlying tissue matrix and thus requiring a scaffold-based application. The engineering of scaffold biointerface close to the matrix via tissue-specific decellularized extracellular matrix (dECM) is crucial in instructing cell behaviour and regulating cell-material interaction in the bioengineering domain. Herein, polycaprolactone (PCL) and TM-dECM (from Sprague-Dawley rats) were combined in a different ratio in nanofibrous form using an electrospinning process and crosslinked via tannic acid. The histological and biochemical assays demonstrated that chemical and enzymatic decellularization steps removed cellular/immunogenic contents while retaining collagen and glycosaminoglycan. The morphological, physicochemical, thermomechanical, contact angle, and surface chemical studies demonstrated that the tannin crosslinked PCL/dECM nanofibers fine-tune biophysical and biochemical properties. The multifaceted crosslinked nanofibers hold the tunable distribution of dECM moieties, assembled into a spool-shaped membrane, and could easily insert into perforated sites. The dECM decorated fibers provide a preferable biomimetic matrix for L929 fibroblast adhesion, proliferation, matrix adsorption, and f-actin saturation, which could be crucial for bioengineering. Overall, dECM patterning, surface hydrophilicity, interconnected microporosities, and multifaceted nanofibrous biosystem modulate cell-scaffold performance and could open opportunities to reconstruct TMP in a biomimetic fashion.

In Situ Forming Cellulose Nanofibril-Reinforced Hyaluronic Acid Hydrogel for Cartilage Regeneration.

Hyaluronic acid (HA) based hydrogels are one of most functional natural biomaterials in the field of cartilage tissue engineering (CTE). Even with the promising advantages of HA hydrogels, the complicated mechanical properties of the native cartilage have not been realized, and fabricating HA hydrogels with excellent mechanical properties to make them practical in CTE still remains a current challenge. Here, a strategy that integrates hydrogels and nanomaterials is shown to form a HA hydrogel with sufficient mechanical loading for cartilage tissue production and recombination. Cellulose nanofibrils (CNFs) are promising nanomaterial candidates as they possess high mechanical strength and excellent biocompatibility. In this study, we developed methacrylate-functionalized CNFs that are able to photo-crosslink with methacrylated HA to fabricate HA/CNF nanocomposite hydrogels. The present composite hydrogels with a compressive modulus of 0.46 ± 0.05 MPa showed adequate compressive strength (0.198 ± 0.009 MPa) and restorability, which can be expected to employ as a stress-bearing tissue such as articular cartilage. Besides, this nanocomposite hydrogel could provide a good microenvironment for bone marrow mesenchymal stem cell proliferation, as well as chondrogenic differentiation, and exhibit prominent repair effect in the full-thickness cartilage defect model of SD rats. These results suggest that the HA/CNF nanocomposite hydrogel creates a new possibility for fabricating a scaffold in CTE.