Porphyrin-Decorated Cu₂O‑Encapsulated Metal–Organic Frameworks as pH-Sensitive Biomimetic Catalysts for Mediating Nitric Oxide Production

Nitric oxide (NO) is an important radical gaseous signal molecule generated by nitric oxide synthase (NOS) enzymes that participates under various physiological and biological functions and has many roles in signal transduction and cancer therapy. Interestingly, the NO levels which could be maintained by l-arginine (l-arg) and S-nitrosothiols (RSNO) play a vital role in the maintenance of normal physiology functions. However, the controlled production of NO under physiological pH remains a challenge. Herein, we report pH-responsive multifunctional nanoplatforms based on porphyrin (FePor)-decorated cuprous oxide (Cu2O)-encapsulated metal–organic frameworks (ZIF-8) and then modify with poly-l-arginine (P-Arg) for mediating the synthesis of NO. Under acid conditions in tumor, Cu2O/FePor@ZIF-8@Arg is broken down to rapidly release the composite of Cu2O/FePor and P-Arg. Cu2O in the unprotected Cu2O/FePor reacts with RSNO to generate both NO and Cu2+. FePor in Cu2O/FePor could act as artificial enzymes for catalyzing the oxidation of P-Arg to produce NO under physiological pH. The results implied that the efficient production of NO could induce cancer cell apoptosis. The presented strategy supplies a promising method for designing and constructing multifunctional nanoplatforms for the development of NO therapeutic strategy

Manipulating Dual Bound States in the Continuum for Efficient Spatial Light Modulator

Spatial light modulators (SLMs) that could control diverse optical properties are highly demanded by many optoelectronic systems. Recently, the integration of nonlinear χ(2) materials and metasurfaces has been recognized as a promising strategy for next-generation SLMs. However, their modulation efficiency still encounters challenges due to low quality factor and weak light–matter interaction. Here, we demonstrate an efficient SLM by manipulating the dual bound state in continuum (BIC) with the assistance of a binary-pore anodic alumina oxide template technique. The coexistence of symmetry-protected BIC and Fabry–Pérot BIC is obtained by a desirable sandwich configuration with a BIC metasurface and EO polymer, which efficiently restrain radiative loss and generate a strong quasi-BIC resonance. The assembled SLM with large absorption and Q-factor delivers a modulation depth of 77% and an f3 dB of nearly 100 MHz. This dual BIC metasurface provides potential for applications including switches, LIDAR, augmented and virtual reality, and so on

Rational Design of a Core–Shelled Ti₃AlC₂@La₂Zr₂O₇ Composite for High-Temperature Broadband Microwave Absorption

Microwave-absorbing materials adapting to high temperatures and harsh environments are in great demand. Herein, a core–shelled Ti3AlC2@La2Zr2O7 (TAC@LZO) composite was designed and fabricated by encapsulating the La2Zr2O7 (LZO) thermal insulation ceramic on the surface of highly conductive Ti3AlC2 (TAC) via chemical coprecipitation and subsequent heat treatment. The continuous LZO ceramic coating on the surface improved the oxidation resistance of the composite at 600 °C and modulated its dielectric properties. The TAC@LZO composite exhibited an excellent microwave absorption performance within the temperature range of 25–600 °C, minimum reflection loss (RLmin) < −55 dB, and effective absorption bandwidth (EAB, RL < −10 dB) of 4 GHz. This work presents an effective approach for developing stable high-temperature microwave absorbers from thermal insulation ceramics

Cryogenic Electron-Beam Writing for Perovskite Metasurface

Halide perovskites (HPs) metasurfaces have recently attracted significant interest due to their potential to not only further enhance device performance but also reveal the unprecedented functionalities and novel photophysical properties of HPs. However, nanopatterning on HPs is critically challenging as they are readily destructed by the organic solvents in the standard lithographic processes. Here, we present a novel, subtle, and fully nondestructive HPs metasurface fabrication strategy based on cryogenic electron-beam writing. This technique allows for high-precision patterning and in situ imaging of HPs with excellent compatibility. As a proof-of-concept, broadband absorption enhanced metasurfaces were realized by patterning nanopillar arrays on CH3NH3PbI3 film, which results in photodetectors with approximately 14-times improvement on responsivity and excellent stability. Our findings highlight the great feasibility of cryogenic electron-beam writing for producing perovskite metasurface and unlocking the unprecedented photoelectronic properties of HPs

Exactly Opposite Luminescence Behaviors of Aggregated Diketopyrrolopyrrole Derivatives Depending on Different Molecular Conformations

A new diketopyrrolopyrrole (DPP) derivative, DPPA-4-Caz, with a distorted molecular conformation has been synthesized, exhibiting aggregation-induced emission (AIE) and mechanofluorochromic (MFC) properties, with a solid-state fluorescence quantum yield of 0.286 and a 37 nm redshift in emission upon grinding. This compound can exhibit either AIE or aggregation-caused quenching effect, and these totally contradictory phenomena are attributed to its two polymorphic forms correspondingly. When the molecule bending is S-type, a loose intermolecular packing pattern is formed in the aggregation state, where the aromatic rings’ rotation is constrained, leading to luminescence. When bending is Z-type, the molecules are parallel-stacked and quench upon aggregation. Five other compounds with similar structures were also synthesized in order to investigate the effects of substituents and alkyl chain length on the properties of AIE and MFC. The results show that the electronic effect of the substituent plays a major role in the production of AIE, while the alkyl chain length has a greater effect on MFC properties

Exactly Opposite Luminescence Behaviors of Aggregated Diketopyrrolopyrrole Derivatives Depending on Different Molecular Conformations

A new diketopyrrolopyrrole (DPP) derivative, DPPA-4-Caz, with a distorted molecular conformation has been synthesized, exhibiting aggregation-induced emission (AIE) and mechanofluorochromic (MFC) properties, with a solid-state fluorescence quantum yield of 0.286 and a 37 nm redshift in emission upon grinding. This compound can exhibit either AIE or aggregation-caused quenching effect, and these totally contradictory phenomena are attributed to its two polymorphic forms correspondingly. When the molecule bending is S-type, a loose intermolecular packing pattern is formed in the aggregation state, where the aromatic rings’ rotation is constrained, leading to luminescence. When bending is Z-type, the molecules are parallel-stacked and quench upon aggregation. Five other compounds with similar structures were also synthesized in order to investigate the effects of substituents and alkyl chain length on the properties of AIE and MFC. The results show that the electronic effect of the substituent plays a major role in the production of AIE, while the alkyl chain length has a greater effect on MFC properties

Exactly Opposite Luminescence Behaviors of Aggregated Diketopyrrolopyrrole Derivatives Depending on Different Molecular Conformations

A new diketopyrrolopyrrole (DPP) derivative, DPPA-4-Caz, with a distorted molecular conformation has been synthesized, exhibiting aggregation-induced emission (AIE) and mechanofluorochromic (MFC) properties, with a solid-state fluorescence quantum yield of 0.286 and a 37 nm redshift in emission upon grinding. This compound can exhibit either AIE or aggregation-caused quenching effect, and these totally contradictory phenomena are attributed to its two polymorphic forms correspondingly. When the molecule bending is S-type, a loose intermolecular packing pattern is formed in the aggregation state, where the aromatic rings’ rotation is constrained, leading to luminescence. When bending is Z-type, the molecules are parallel-stacked and quench upon aggregation. Five other compounds with similar structures were also synthesized in order to investigate the effects of substituents and alkyl chain length on the properties of AIE and MFC. The results show that the electronic effect of the substituent plays a major role in the production of AIE, while the alkyl chain length has a greater effect on MFC properties

Adjusting Emission Wavelength by Tuning the Intermolecular Distance in Charge-Regulated Supramolecular Assemblies

Controlling and measuring intermolecular distance in supramolecular structures are particularly important, as the intermolecular distance and the corresponding intermolecular forces dominate the features of materials. Rationally tuning the intermolecular distance in the assemblies can be achieved by adjusting/balancing different physical/chemical forces and characterized by various physical methods such as fluorescence. Here we report the use of charge-regulated spontaneous, reversible, self-assembled systems from molecular metal–organic cages (MOCs) with moderately adjustable intermolecular distances in their reversible assemblies. The MOCs contain luminogens with aggregation-induced emission (AIEgens) characteristics. Instead of aggregating them via van der Waals forces (traditional aggregation-induced emission, AIE), the cages can be self-assembled spontaneously into hollow, single-layered, stable blackberry-type supramolecular structures with slightly longer and moderately adjustable intermolecular distance (<1.0 nm), at which the rotation of single bonds in the fluorophores is only partially (and adjustably) limited, leading to strong wavelength rationally tunable (to certain extent) emission from stable dispersed solutions via electrostatic interaction

Sensitive Electrochemical Sensor for Glycoprotein Detection Using a Self-Serviced-Track 3D DNA Walker and Catalytic Hairpin Assembly Enzyme-Free Signal Amplification

Approaches for the detection of targets in the cellular microenvironment have been extensively developed. However, developing a method with sensitive and accurate analysis for noninvasive cancer diagnosis has remained challenging until now. Here, we reported a sensitive and universal electrochemical platform that integrates a self-serviced-track 3D DNA walker and catalytic hairpin assembly (CHA) triggering G-Quadruplex/Hemin DNAzyme assembly signal amplification. In the presence of a target, the aptamer recognition initiated the 3D DNA walker on the cell surface autonomous running and releasing DNA (C) from the triple helix. The released DNA C as the target-triggered CHA moiety, and then G-quadruplex/hemin, was formed on the surface of electrode. Eventually, a large amount of G-quadruplex/hemin was formed on the sensor surface to generate an amplified electrochemical signal. Using N-acetylgalactosamine as a model, benefiting from the high selectivity and sensitivity of the self-serviced-track 3D DNA walker and the CHA, this designed method showed a detection limit of 39 cell/mL and 2.16 nM N-acetylgalactosamine. Furthermore, this detection strategy was enzyme free and exhibited highly sensitive, accurate, and universal detection of a variety of targets by using the corresponding DNA aptamer in clinical sample analysis, showing potential for early and prognostic diagnostic application

Green Starch-Based Hydrogels with Excellent Injectability, Self-Healing, Adhesion, Photothermal Effect, and Antibacterial Activity for Promoting Wound Healing

Hydrogel materials have proven valuable in wound healing, but improving the safety of these hydrogels is still challenging. Therefore, designing multifunctional natural polymeric-based hydrogels with excellent mechanical properties to replace toxic or potentially risky, refractory chemical polymer-based hydrogels such as polyacrylamide and polyethylene glycol is of particular significance. Here, a green starch-based hydrogel (Starch@Ca/CGC hydrogel) with injectability, self-healing, and instant adhesion was constructed by coordination interaction, electrostatic interaction, and intramolecular and intermolecular hydrogen bonds. Therein, natural bioactive small molecules gallic acid (GA) and carvacrol (CA) were coordinated with metal ions by the ultrasonic-triggered self-assembly and ionic cross-linking codriven strategy to prepare Cu-gallic acid-carvacrol nanospheres (CGC NPs), which conferred the hydrogel with near-infrared light (NIR)-controlled CA release and photothermal synergistic sterilization properties, as well as antioxidant and anti-infection capabilities. More importantly, the multifunctional hydrogel platforms could completely cover an irregular wound shape to prevent secondary injury and significantly accelerate wound healing under NIR with more skin appendages like hair follicles and blood vessels appearing. Therefore, it is expected that this starch-based hydrogel could serve as a competitive multifunctional dressing in the biomedical field, including bacteria-derived wound infection and other tissue repair