Science China Materials最新文献

Ultrasmall gold nanoparticles (AuNPs, d < 3 nm) have become an outstanding type of theranostic probe because of tunable luminescence, superior pharmacokinetics, low toxicity, and rich surface chemistry. The second near-infrared (NIR-II) luminescence offers unique merits, such as deep tissue penetration, high spatial resolution, and admirable signal-noise ratio, creating many opportunities and challenges for ultrasmall AuNPs in advanced biomedical applications. Herein, this review illustrates the recent advances of ultrasmall AuNPs in understanding the NIR-II mechanisms, clearance pathways, and related biomedical applications. We firstly elucidate the present understanding of the NIR-II mechanisms of ultrasmall AuNPs, along with some effective strategies for enhancing NIR-II luminescence, namely heterometal doping and surface rigidification. Then, we discuss the impact of their structures on liver clearance and kidney clearance. Further, we highlight the major biomedical applications of these ultrasmall AuNPs in bioimaging, antibacterial, nanomedicine, and drug delivery. Finally, we offer some outlooks on the challenges and chances of ultrasmall AuNPs for later research endeavors to promote their clinical translation in the biomedical field.

Post-resection recurrence remains a severe problem in melanoma treatment. New therapeutic strategies, such as chemodynamic therapy (CDT), exhibit high specificity and responsiveness, demonstrating potential to elicit antitumor immune responses by triggering immunogenic cell death (ICD). However, the efficacy of CDT still faces challenges from the immunosuppressive tumor microenvironment (TME) characterized by elevated lactate levels. Herein, we propose a strategy to construct an immunomodulatory hydrogel to synergistically reprogram tumor-associated macrophages and amplify ICD to inhibit melanoma recurrence after surgery. The hyaluronic acid hydrogel containing borosilicate glasses (BGs) and Fe₃O₄ nanoparticles (HBF hydrogel) are obtained, which can neutralize tumor acidity to reprogram macrophages to M1 phenotype. Furthermore, the HBF hydrogel induces reactive oxygen species production in melanoma cells, which could induce ICD through CDT and stimulate strong antitumor immune responses, thereby promoting tumor immunotherapy. The cooperative ICD induced by CDT and immunosuppressive TME remodeling leads to effective suppression of tumor recurrence. This work provides a promising strategy for immunomodulation-enhanced melanoma therapy through the fabrication of hydrogel to prevent postsurgical tumor recurrence.

Bismuth oxyhalide (BiOCl) holds promising potential as the anode for sodium-ion batteries (SIBs) due to its high theoretical capacity and unique layered structure. However, its practical applications are hindered by challenges such as large volume variations during cycling, the ambiguous Na⁺-storage mechanism, and complex synthesis methods. Here, we present a facile and scalable strategy to fabricate a high-performance BiOCl nanosheets anode for SIBs. Through comprehensive in-situ and ex-situ microscopic characterizations and electrochemical analysis, we reveal that the sodiation/desodiation process of the BiOCl nanosheets anode leads to the formation of metallic Bi and Na₃OCl. The metallic Bi acts as an active material for Na⁺ storage in subsequent cycles, while the formed Na₃OCl enhances the stability of the solid-electrolyte interphase (SEI) layer and facilitates Na⁺ transport. Additionally, the metallic Bi gradually transforms into a nanoporous structure during cycling, improving Na⁺ transport and mitigating volume variations. As a result, the BiOCl nanosheets anode exhibits outstanding electrochemical performance, with impressive rate capability and cycling stability. Furthermore, full cells paired with the Na₃V₂(PO₄)₃ (NVP) cathode and pre-cycled BiOCl nanosheets anode also demonstrate a superior rate and cycling performance. This work offers valuable insight into the development of high-performance anodes for advanced SIBs.

Rationally modulating the adsorption configuration of the key *CO intermediate could facilitate carbon-carbon (C-C) coupling to generate multi-carbon products in the electrochemical CO₂ reduction reaction. In this work, theoretical calculations reveal that C-C coupling via atop-adsorbed *CHO and hollow-adsorbed *CO over Cu sites is an energetically favorable pathway. As a proof of concept, a tandem trimetallic AuAgCu heterojunction (Au@Ag/Cu) was prepared, where the atop-adsorbed *CO over Au@Ag sites could migrate to Cu sites with hollow adsorption configuration, and then the asymmetric C-C coupling via transferred hollow-adsorbed *CO and existed atop-adsorbed *CHO over Cu sites facilitates the formation of the ethanol product, exhibiting a maximum Faraday efficiency of 65.9% at a low potential of −0.3 V vs. reverse hydrogen electrode. Our work provides new insights into the intrinsic understanding of tandem catalysis by regulating adsorption configuration of the intermediate products.

The development of high-performance near-infrared (NIR) absorbing electron acceptors is a major challenge in achieving high short-circuit current density (J_SC) to increase power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, three new multi-heteroatomized Y-series acceptors (bi-asy-Y-Br, bi-asy-Y-FBr, and bi-asy-Y-FBrF) were developed by combining dual-asymmetric selenium-fused core and brominated end-groups with different numbers of fluorine substitutions. With gradually increasing fluorination, three acceptors exhibit red-shift absorption. Among them, bi-asy-Y-FBrF presents planar molecular geometry, the maximum average electrostatic potential, and the minimum molecular dipole moment, which are conducive to intramolecular packing and charge transport. Moreover, D18:bi-asy-Y-FBrF active layer presents higher crystallinity, more suitable phase separation, and reduced charge recombination compared to D18:bi-asy-Y-Br and D18:bi-asy-Y-FBr blends. Consequently, among theses binary OSCs, D18:bi-asy-Y-FBrF device achieves a higher PCE of 15.74% with an enhanced J_SC of 26.28 mA cm⁻², while D18:bi-asy-Y-Br device obtains a moderate PCE of 15.04% with the highest open-circuit voltage (V_OC) of 0.926 V. Inspired by its high V_OC and complementary absorption with NIR-absorbing BTP-eC9 as acceptor, bi-asy-Y-Br is introduced into binary D18:BTP-eC9 to construct ternary OSCs, achieving a further boosted PCE of 19.12%, which is among the top values for the reported green solvent processed OSCs.

As future soft robotic devices necessitate a level of complexity surpassing current standards, a new design approach is needed that integrates multiple systems necessary to synchronize the motions of soft actuators and the response of signals, thereby enhancing the intelligence of flexible devices. Herein, we propose a liquid crystal elastomer unit cell-based platform that organizes the cells in a group to create expandable functions. One unit cell behaves like a flexible module that can expand biaxially into a specific, stable, and controllable pattern. Collaborating the unit cells in different manners results in an adaptable soft grasper, a half-adder for information processing, and a tunable phononic bandgap. This implies a high level of reconfigurability and scalability in both structures and functions by elegantly reassembling the unit cells. This design strategy has the potential to integrate multiple functions that traditional soft actuators cannot accommodate, providing a platform for developing intelligent soft robotics.

Zinc powder-based anodes encounter significant challenges, including severe side-reactions and non-uniform Zn plating-stripping processes. These issues lead to poor reversibility and low zinc utilization, which substantially impede their practical applications. Herein, we fabricated a multifunctional carbonyl-containing zinc metharcylate (ZMA) layer on the surface of three-dimensional (3D) zinc powder anode through in-situ modification. The ZMA layer with high electronegativity and highly nucleophilic carbonyl group assists the de-solvation process, which is conducive to the Zn²⁺ transport and homogenization of the ionic flux. In addition, the hydrophobic carbon chains in ZMA work as a protective layer to reduce the Zn powder direct contact with free-water and significantly improving side-reactions resistance. Finally, through the synergistic effect of ZMA and 3D Zn structure, the prepared electrode could cycle stably at 20 mA cm⁻²/20 mAh cm⁻² for 1153 h (depth of discharge: 38.10%). The stable 3D Zn-MnO₂ battery with a high capacity retention (84.2% over 500 cycles) is also demonstrated.

Zinc and its alloys provide a scalable alternative to the list of biodegradable metals due to its moderate degradation rates and biocompatible degradation products. However, one of the challenges impeding their clinical applications is the uncontrollable and unstable interfacial reactions between zinc implants and the corrosive media. In this study, we report a facile synthesis of metal–organic framework (MOF) nanocrystal coating with tunable thickness on the high-strength Zn-0.8Li alloy matrix for controlled corrosion. The as-obtained dense and uniform MOF nanocrystals form a strong connection with the zinc matrix via coordination bond so as to maintain the mechanical properties, and meantime provide highly rough surfaces exhibiting tunable wettability. The varied MOF coating thus regulate the interface structure between the zinc matrix and corrosive media to control the degradation behavior. Excellent antibacterial activity and biocompatibility are also achieved because of the unique topology morphologies, surface superhydrophilicity, as well as the dynamic Zn²⁺ release. This study sheds valuable lights on the design of MOF-functionalized metal implants for practical use and also triggers extensive applications of MOF in biomaterials.