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Nanozyme-enhanced mitophagy to improve the efficacy of mesenchymal stem cells in myocardial infarction therapy

Mesenchymal stem cell therapy has emerged as a promising approach for the treatment of myocardial infarction. However, the challenge of low cell survival and retention post injection, particularly under the high levels of reactive oxygen species (ROS) and oxidative stress at the infarct site, has hindered their clinical application. Additionally, traditional drug delivery methods, such as intravenous injection, cannot meet the demand for long-term stem cell residence at the infarct site, which is another critical issue that impedes the therapeutic efficacy of stem cells. Herein, we synthesized indocyanine green-enriched Prussian blue nanozyme, called PB@PEI@ICG, which not only possessed remarkable ROS scavenging capability but also exhibited superior fluorescent tracer property. Subsequently, we engineered mesenchymal stem cells (MSCs) with PB@PEI@ICG by co-culture and found that the introduction of the nanozyme significantly enhanced mitophagy by BNIP3 and PINK1 pathways, which in turn promoted ROS scavenging and protected MSCs from cell death induced by the harsh infarct microenvironment. Furthermore, we employed pericardial injection as an alternative delivery method to prolong the residence time of MSCs at the infarct site, enabling real-time tracking via the fluorescence property of the nanozymes. The results demonstrated that PB@PEI@ICG nanozyme could significantly improve the survival and retention of MSCs at the infarct site, thereby enhancing the therapeutic effect for myocardial infarction. In conclusion, this study presents a novel strategy for stem cell therapy in myocardial infarction by using mitophagy-enhancing nanozyme to scavenge ROS for enhancing the therapeutic potential of stem cells.

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Versatile hydrogel-based drug delivery platform for multimodal cancer therapy from bench to bedside

Hydrogel exhibits a promising application prospect for multimodal cancer therapy in clinic compared with other conventional drug delivery platforms, which is predominantly attributed to its excellent biocompatibility, local injectability and retention, sustained drug release behavior, multiple administration approaches, and flexible drug loading capacity. Hydrogel can be further classified into physical, chemical, and multiple crosslinked hydrogels according to the formation mechanisms. The emergence of hydrogel enables antineoplastic agents to be delivered in much broader routes compared with numerous traditional carriers. Intratumoral injection, peritumoral injection, and postoperative implantation are regarded as the three momentous approaches for administrating macroscopic hydrogel, while nanoscopic hydrogel can also be applied through intravenous injection. In addition, both monotherapy and combination therapy against cancer are available to be realized through hydrogel delivery system, providing a valuable opportunity to enhance antitumor effect and achieve synergistic efficacy. Recently, several hydrogel products have already been approved by FDA, exerting essential roles against cancer in clinic. Meanwhile, there have also been various types of hydrogel delivery systems for cancer therapy in clinical trial stage. To sum up, hydrogel is a versatile drug delivery platform with good clinical translation potential, offering a promising and meaningful strategy for cancer therapy.

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Artificial nociceptor based on interface engineered ferroelectric volatile memristor

Recent advancements in neuromorphic computing driven by memristors, which emulate biological synapses and neurons, have spurred the development of innovative information technologies. To extend memristor applications to artificial nervous systems, electronic receptors are crucial for converting external stimuli into signals for the internal nervous system. Key requirements for integrating neuron devices into neuromorphic computing include achieving threshold behavior, minimizing power consumption, and ensuring compatibility with complementary metal-oxide semiconductor (CMOS) technology. Hafnium-based ferroelectric memristors are known for their robust ferroelectric properties at nanoscales and compatibility with CMOS technology. However, their non-volatile resistive switching has historically limited their suitability for neuron sensory applications requiring threshold switching. This study demonstrates threshold switching behavior in a TiN/Hf0.67Zr0.33O2(HZO)/TiOx/TiN heterostructure by incorporating a nanoscale TiOx interfacial layer as an oxygen reservoir. This layer facilitates the formation of oxygen vacancies within the ferroelectric HZO layer, serving as internal charge trap sites. As a result, hafnium-based ferroelectric memristors exhibit volatile switching characteristics, enabling them to function as nociceptive devices through internal charge trapping and detrapping mechanisms. These volatile memristors are suitable for artificial nociceptor systems requiring responses such as threshold detection, relaxation, allodynia, and hyperalgesia to external stimuli. This capability opens avenues for developing advanced humanoid robots capable of rapid adaptation and response in challenging environments such as outer space or hazardous conditions, leveraging real-time sensory processing for effective operation and survival.

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Interplay of piezoelectricity and electrical stimulation in tissue engineering and regenerative medicine

Bioelectronic medicine, involving physiologically relevant biophysical stimulation and piezoelectric biomaterials is perceived to transform the field of regenerative bioelectronics. The combinatorial effect has shown remarkable potential in guiding cell behavior and promoting the development of functional tissue-engineered constructs. Smart piezoelectric biomaterials, capable of generating electric charges under mechanical stress or deformation, have emerged as key players in tissue engineering applications. This comprehensive review explores the interplay between electrical stimulation, piezoelectric biomaterials, and cell functionality in regeneration of neural, bone, cardiac, skin, and vascular tissues. The inherent electrical activity (biopiezoelectricity) empowers piezoelectric scaffolds to replicate natural processes in the extracellular matrix. The synergy between surface charge polarization or electric field stimulation and the functional properties of piezoelectric biomaterials have been critically analyzed. These analyses demonstrate how such synergistic effects can modulate in vitro cell functionality and in vivo tissue regeneration. Moreover, the integration of data science approaches has the potential to optimize the design of piezoelectric scaffolds for specific tissue engineering and regenerative medicine applications.

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3D-printed polymer-derived ceramics with tunable cellular architectures

Ceramic materials possess high mechanical strength and environmental stability, but their brittleness limits their suitability for structural applications. A solution lies in using polymer-derived ceramics (PDCs), which offer enhanced toughness and versatility in shaping unlike traditional ceramic processing methods. This study explores tunable ceramic cellular architectures based on triply periodic minimal surface (TPMS) designs, fabricated via stereolithography (SLA) using a silicon oxycarbide precursor formulated for vat photopolymerization. By combining the preceramic polymer with a photoinitiator, crosslinkers, and other additives, intricate shapes are 3D-printed and then pyrolyzed under nitrogen, resulting in PDCs with complex TPMS geometries. The toughness, strength, and stiffness of the 3D-printed structures are evaluated through quasi-static compression experiments. Comprehensive material and microstructural characterizations of the PDCs are performed pre- and post-pyrolysis, employing visual inspection, X-ray micro-tomography, thermogravimetric analysis, energy dispersive X-ray spectroscopy, density, and rheological measurements. Optimization of 3D printing and pyrolysis parameters yields ceramic structures with 2.2 MPa compressive strength and 330 MPa stiffness with a lattice density of 0.5 g cm-3. The ceramic material, including porosity, had a maximum density of 1.63 ± 0.01 g cm-3. This low-cost SLA 3D printing technique is ideal for creating thin features and customized structures of bio-inspired, architectured ceramics. Furthermore, the process exhibits excellent printability, being compatible with common and cost-effective SLA, DLP, and LCD 3D printers.

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Lubricating adhesive hyaluronate patch promotes cartilage regeneration and functional restoration in osteoarthritis

Osteoarthritis (OA) is a common chronic degenerative joint disease characterized by gradual deterioration and pain. Viscosupplementation, involving hyaluronic acid (HA) injection into the affected joint, is a minimally invasive option to reduce pain by improving joint lubrication and potentially avoiding the need for replacement surgery. However, the low adhesion and rapid degradation of HA often lead to inadequate therapeutic effects. In this study, we present lubricating adhesive HA-based hydrogel patches designed to effectively treat OA. The HA patches, modified with pyrogallol, have high elastic and compressive moduli, delaying degradation when exposed to external stimuli. Furthermore, they securely adhere to cartilage tissue surfaces and efficiently lubricate damaged cartilage, leading to a reduced friction and wear. In addition to these benefits, our HA patches exhibit scavenging effect of reactive oxygen species and sustainably release an encapsulated anti-inflammatory drug (dexamethasone: Dex). These features further enhance their therapeutic potential for OA treatment. In a mouse OA model, the hydrogel patches loaded with Dex promote healing of damaged cartilage and restore its motor function. Overall, our bioinspired HA hydrogel patches present a promising treatment option for managing the debilitating joint disease by offering enhanced adhesion, lubrication for cartilage protection, antioxidant effect, and sustained drug release.

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High performance flexible green triboelectric nanogenerator with polyethylene oxide/mica tribo-positive composite material

Innovating novel, green, biodegradable, and recyclable polymers are critical for the development of environmentally sustainable solutions, eliminating concerns of pollution and microplastic accumulation. Herin, this study presents remarkably enhanced tribo-positive polyethylene oxide (PEO) polarity, by incorporating for the first time, a clay inorganic filler, creating a novel biodegradable composite triboelectric material. The low-cost composite comprised a biodegradable polymeric PEO matrix, an abundant naturally sourced muscovite mica micro-platelet filler, and integrated simple material fabrication methods. A 4 cm2 PEO/Mica film was paired with polytetrafluoroethylene (PTFE), generating a peak-to-peak voltage, current density, and transferred charge density of respectfully, 296 V, 24.2 mA m−2, and 110.3 µC m−2. Reducing the film thickness to 40 µm dramatically enhanced the electrical output, resulting in a peak-to-peak voltage and instantaneous power density of respectfully, 424 V and 12.1 W m−2. The addition of mica greatly improved the dielectric permittivity, promoting the outstanding triboelectric performance. The composite material's long-term stability and flexibility demonstrated significant advantages for self-powering small electronic systems. Furthermore, PEOs facile water solubility allowed mica separation, recovery, recyclability, and integration within new PEO/Mica films, resulted in preserved triboelectric outputs. The PEO/Mica composite delivers exceptional sustainable, recyclable, and tribo-positive attributes, serving as an excellent energy harvesting solution.

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