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Nerve injury can lead to defects in related motor functions. It is critical to achieve long‐term and convenient real‐time evaluation of motor function recovery status during nerve injury repair. In this study, an implantable PLLA/BTO piezoelectric sensor (PBPS) with good biodegradability and biocompatibility for real time evaluation of the motor function recovery after nerve injury is developed. PLLA fibers doped with BTO are employed as piezoelectric material in PBPS, which can convert the biomechanical signals generated by motion into electrical signals. PBPS can be implant simultaneously with commonly used tissue scaffolds for treatment in the rats with sciatic nerve injury. The linearity of the pressure and the output voltage of PBPS is ≈0.9445. For the evaluation effectiveness, as the treatment process progresses, the signals generated by PBPS exhibited good consistency with EMG signals, indicating effectively evaluation of the motor function. Moreover, the integration of PBPS and wireless module can break the limitations of time and space for sensing and realize wireless evaluation of motor function in rat. The implantable sensor based on PBPS may bring new ideas for the development of implantable bioelectronics. [ABSTRACT FROM AUTHOR]

Biodegradable polymers (BPs)‐based triboelectric nanogenerators (TENGs) have advantages, including biocompatibility and biodegradability. However, biodegradable TENGs (BD‐TENGs) possess relatively low output performance, limiting their application due to the small differences in triboelectric polarities for most BPs. Molecular doping is a simple and effective method in altering the triboelectric polarity of triboelectric materials and improving the output performance of BD‐TENGs. However, there is a lack of laws and mechanism about the differences in triboelectric polarities of different doped molecules, especially of molecules with biodegradability and biocompatibility. Here, kinds of doping molecules are selected for doping in tribopositive and tribonegative materials, respectively, and their triboelectric polarities and related laws are researched. In particular, the output performance of BD‐TENG is improved several times by doping small amounts of poly (propylene glycol) (PPG) and ethyl cellulose (EC), with enhanced resolution in abnormal respiratory signal monitoring. This work not only provides theoretical guidance for the selection of triboelectric molecules but also conducts in‐depth research in molecular‐level triboelectric mechanisms. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors are valuable in applications such as electronic skin, smart robots, artificial prosthetics, and wearable electronics. In this study, a fully packaged, flexible, self‐powered, long‐term stable sensor array based on piezoelectrets is developed for pressure monitoring. A pressure sensor with a microcavity structure and a thickness of 500 µm achieved an impressive piezoelectric coefficient of 23.8 pC N−1 and a fast response time of 93 ms. The sensor yielded an output voltage of 0.26 V when subjected to a force using 0.3 g soybeans, and it displayed a remarkable linear relationship (R2 = 0.992) between force and electricity with pressure ranging from 1.4 to 13.6 N and a sensitivity of 9 mV N−1. Real‐time monitoring of sound vibration, radial artery pulse, and finger movement is demonstrated along with the successful recording of dynamic pressure changes within the porcine knee joint. It holds potential for fields such as monitoring pressure changes in the movement of human bodies and robotics and can contribute significantly to pressure assessment during total knee replacement. [ABSTRACT FROM AUTHOR]

Precision medicine requires precise regulation of drugs in terms of time, space, and dosage. Exogenous control systems, such as electrical responsiveness, have made great progress. However, wearable or implantable controlled drug release devices still face major challenges due to limitations including limited battery life, large size, and fixed power supply. To overcome these limitations, the fabrication of autonomous devices is available to endure extended periods without reliance on external power sources. As a promising strategy, nanogenerators (NGs) turn body mechanical energy into electricity, powering long‐term drug release. In this review, the current status of drug delivery systems (DDS) is briefly outlined and the importance of self‐driven controlled drug release systems is emphasized. The main types and operational mechanisms of various nanogenerators are introduced. This review also focuses on summarizing the latest progress of self‐powered controlled drug release systems based on nanogenerators (NG‐based CDRs). Additionally, their applications in the field of drug release are introduced in detail. Finally, the existing challenges and future trends of self‐powered NG‐based CDRs are discussed from the perspectives of clinical needs and practical translation. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic perovskite (HOIP) ferroelectrics with high Curie temperature (Tc), typified by the lead halide hybrid perovskite ferroelectrics, are developing rapidly owing to their maneuverable ferroelectricity at high temperatures. However, acquiring high‐Tc lead‐free HOIP ferroelectrics via rational strategy still needs development. In this study, a brand‐new program by modulating the steric confinement in a cuplike cavity to design high‐Tc bismuth‐halide ferroelectrics [H2mdap]BiX5 (H2mdap = N‐Methyl‐1,3‐Propanediamine, X = Cl (1), Br (2), I(3)) is proposed. Emphatically, the Tc enhanced dramatically from 264 K of 3 to 318 K of 2 and 377 K of 1, induced by the substitution of Br and Cl to I, accompanied with an interesting transition from second‐order phase transition (for 3) to the first‐order one (for 1 and 2). The extent of Tc increase is up to 113 K, which far outweighs that of reported Pb‐halide hybrid ferroelectrics. Structural and computational analyses elucidate that this unprecedented improvement of Tc is due to the higher phase transition energy barriers induced by modulating the steric confinement of cuplike cavity via halogen substitution. These results will provide new inspiration for designing high‐Tc lead‐free HOIP ferroelectrics. [ABSTRACT FROM AUTHOR]

It is important to detect light of low power density sensitively and fast for the application of optical communication, environmental monitoring, astronomy, and national securities. However, ZnO‐based photodetectors exhibit long decay time owing to the persistent photoconductivity (PPC) and are hard to detect light with low power density efficiently. Here, a practical strategy is utilized to improve the performance of ZnO‐based photodetectors by coupling the pyroelectric effect of ZnO with localized surface plasmon resonance (LSPR) of Au nanoparticles subtly. Hence, a self‐powered photodetector is demonstrated, which is integrated with ZnO/CuO core–shell nanorods and Au nanoparticles to detect UV to vis light. This self‐powered photodetector achieves fast and sensitive detection of UV when power density is 68 nW cm−2. The performance is significantly improved than the photodetectors without Au nanoparticles. The optimal responsivity and detectivity under the same power density of UV at 325 nm are 1.4 × 10−4 A W−1 and 3.3 × 1011 Jones. Response/recovery time is remarkably shortened to ≈10 ms. The results indicate that the material configurations and design concept make the device applicable for self‐powered, high‐performance photodetectors, and provide further promoted understanding of LSPR enhanced performance of photodetectors. [ABSTRACT FROM AUTHOR]

The blind mainly relies on Braille books to obtain text information. However, Braille books with invariable content are ponderous and inconvenient to read. Hence, it is essential to find a safe, simple and effective method to develop new Braille devices. This advanced method promises to be the next generation Braille book that is refreshable, flexible, and portable. Therefore, a safe dielectric elastomer Braille device actuated by a triboelectric nanogenerator is designed. It is easy to fabricate, inexpensive, and safe without any potential hazard for blind people. For triboelectric nanogenerators, the friction between two thin films can generate a voltage over 3 kV with a current of just 2 µA to deliver a shape change of the dielectric elastomer membrane. In the meantime, with the support of the pressor air in the chamber, the membrane will be raised up to be a touchable Braille dot. In addition, a programmed switch matrix is designed to control the Braille device with multiple dielectric elastomer dots to realize complicated refreshable display, providing a possibility of a page‐size and portable braille e‐book for the blind in the near future. [ABSTRACT FROM AUTHOR]

The treatment outcomes of nanomedicines against colorectal cancer are severely restricted by their insufficient accumulation in the tumor tissues, unsatisfactory antitumor effect, and weak immunometabolic modulation. To address these issues, flying‐saucer‐shaped nanoheterojunctions by coating copper oxide (CuxO) onto the surface of PEGylated zinc oxide (ZnO) nanoparticles are constructed. When exposed to ultrasound, the resultant CuxO@ZnO nanoheterojunctions exhibit increased locomotor activities, facilitating colorectal mucus infiltration, deep tumor penetration, and tumor cell internalization. The decoration of CuxO suppresses the rapid recombination of electrons and holes in CuxO@ZnO exposed to ultrasound, promoting the production of singlet oxygen and hydroxyl radical, which are generated by CuxO through a Fenton‐like chemodynamic reaction and CuxO@ZnO through sonodynamic reaction. After rectal administration, the sono‐chemodynamic CuxO@ZnO plus PD‐L1 antibodies effectively inhibit the growth of orthotopic and distant tumors. It elicits immunometabolic responses by inducing immunogenic cell death, activating the interferon genes signaling pathway stimulator, and inhibiting glucose transport and the glycolytic signaling pathways. This combined modality also increases the proportion of beneficial microbes (e.g., Bifidobacterium) and decreases the abundance of harmful microorganisms (e.g., Romboutsia) in the intestine. This treatment modality (CuxO@ZnO plus ultrasound and PD‐L1 antibodies) is a promising strategy for the synergistic treatment of colorectal cancer. [ABSTRACT FROM AUTHOR]

Schottky and Ohmic contacts–based electronics play an important role in highly sensitive detection of biomolecules and neural electric impulses, respectively. The reversible conversion between these two contacts appears especially important for multifunctional sensing by just one biosensor. Here, Schottky barrier height (SBH) is successfully tuned by triboelectric nanogenerator (TENG) and the same device is made to achieve reversible conversion between Schottky contact and Ohmic contact. In the same Schottky to Ohmic reversible (SOR) biosensor, highly sensitive detections of biomolecule (i.e., neurotransmitter) and neural electric signal are achieved at different contact states. The SOR biosensor reveals the feasibility of using one device to realize multifunctional detection. This work proposes a simple and significant method to achieve reversible tuning between the Schottky contact and Ohmic contact on one device by TENG, which exhibits great potential in developing multifunctional and high‐sensitivity biosensors, rectifiers, and other functional electronic devices. [ABSTRACT FROM AUTHOR]

Prevention of aseptic loosening, the main reason for secondary surgery of bone implants, is of great crucial clinical importance. As a promising bioactive material to promote bone regeneration, the piezoelectric materials for preventing aseptic loosening has not been reported. Here, a surface coating is presented for implants based on piezoelectric poly(L‐lactic acid) (PLLA). The coating ingeniously utilizes zoledronic acid (ZA), a drug used to treat osteoporosis, as a nucleating agent to enhance the piezoelectricity of PLLA. The coating can not only provide a continuous porous piezoelectric environment to stimulate osteogenic differentiation without intervention, but also effectively inhibit the osteolytic activity of osteoclasts through the slow release of ZA, achieving long‐term effectiveness with a single implantation. The rat femur cavity implantation experiment suggests that, the PLLA/ZA coating can rapidly initiate osseointegration of the implant and effectively mitigate the risk of aseptic loosening, even in the presence of metal submicroscopic particles that induce aseptic loosening. This strategy of piezo‐enhanced PLLA drug‐loaded coating may provide a new idea for the surface modification of bone implants. [ABSTRACT FROM AUTHOR]

Changes in endocardial pressure (EP) have important clinical significance for heart failure patients with impaired cardiac function. As a vital parameter for evaluating cardiac function, EP is commonly monitored by invasive and expensive cardiac catheterization, which is not feasible for long‐term and continuous data collection. In this work, a miniaturized, flexible, and self‐powered endocardial pressure sensor (SEPS) based on triboelectric nanogenerator (TENG), which is integrated with a surgical catheter for minimally invasive implantation, is reported. In a porcine model, SEPS is implanted into the left ventricle and the left atrium. The SEPS has a good response both in low‐ and high‐pressure environments. The SEPS achieves the ultrasensitivity, real‐time monitoring, and mechanical stability in vivo. An excellent linearity (R2 = 0.997) with a sensitivity of 1.195 mV mmHg−1 is obtained. Furthermore, cardiac arrhythmias such as ventricular fibrillation and ventricular premature contraction can also be detected by SEPS. The device may promote the development of miniature implantable medical sensors for monitoring and diagnosis of cardiovascular diseases. A miniaturized flexible self‐powered endocardial pressure sensor (SEPS) based on a triboelectric nanogenerator is demonstrated in a porcine model. The SEPS achieves ultrasensitivity, real‐time monitoring, and mechanical stability in vivo. Atrial fibrillation and ventricular premature contraction are also detected by the SEPS. This device may promote the development of miniature implantable medical sensors for monitoring and diagnosis of cardiovascular diseases. [ABSTRACT FROM AUTHOR]