Current treatments for chronic diabetic wounds remain unsatisfactory due to the lack of ideal wound dressings that can integrate matching mechanical strength, fast self‐healability, facile dressing change, and multiple therapeutic effects into one system. In this work, benefiting from the catechol groups and therapeutic effect of epigallocatechin‐3‐gallate (EGCG, green tea derivative), a smart hydrogel dressing can be conveniently obtained through copolymerization of the complex formed by EGCG and 3‐acrylamido phenylboronic acid (APBA) (the formation of boronate ester bond) and acrylamide. The resulting hydrogel features adequate mechanical properties, self‐healing capability, and tissue adhesiveness. Otherwise, the substantial release of EGCG can not only realize anti‐oxidation, antibacterial, anti‐inflammatory and proangiogenic effect, and modulation of macrophage polarization to accelerate wound healing, but also facilitate easy dressing change. This advanced hydrogel provides a facile and effective way for diabetic chronic wound management and may be extended for the therapy of other complicated wound healings.

Understanding the key factors influencing the mechanical and electrical properties of semiconducting polymers is crucial to the development of stretchable electronics. In this work, a high-mobility diketopyrrolopyrrole-based conjugated polymer with varied number-average molecular weights (M n ) was used as the model system to explore the impact of molecular weight on the electrical and mechanical properties. Higher-M n films are more ductile and stretchable. Both hole mobilities of thin-film transistors and elastic modulus become maximum at a moderate M n of 88 kg/mol. It was found that film continuity, entanglements, and relative degree of crystallinity are critical factors for approaching the best device performance and highest elastic modulus. The transition molecular weight of a given polymer semiconductor is the key to achieving stretchable high-mobility transistors that are practically useful. This work would help to offer guidance to manipulate the mechanical and electrical properties for other polymer semiconductors.

No abstract

To simultaneously obtain outstanding stretchability, strength, and charge mobility of conjugated polymers (CPs) has remained a challenge for the field of stretchable electronics to date. Herein, we propose a strategy of increasing the molecular weight of a near-amorphous CP poly(indacenodithiophene-co-benzothiadiazole) (IDT-BT) to an ultrahigh level to overcome the trade-off. Detailed molecular weight-dependent study confirms that increasing the molecular weight can simultaneously enhance the mechanical and charge transport properties of IDT-BT, owing to the higher extent of chain entanglement and a larger range of charge transport along the backbone. Ultrahigh-molecular-weight (1049.6 kg mol −1 , weight average) IDT-BT exhibited the highest mobility of 2.63 cm 2 V −1 s −1 , modulus of 1126.7 MPa, elastic recovery >80%, crack onset strain >100%, fracture strain ≥20%, and a crack-free morphology after 100 cycles of strain. To the best of our knowledge, the ultrahigh-M w IDT-BT outperforms previously reported stretchable CPs by exhibiting enhanced elasticity, strength, and charge mobility at the same time.

No abstract

The development of a highly effective photosensitizer (PS) that can be activated with a low-power single light is a pressing issue. Herein, we report a PS for synergistic photodynamic and photothermal therapy constructed through self-assembly of poly­(selenoviologen) on the surface of core-shell NaYF4:Yb/Tm@NaYF4 upconversion nanoparticles. The hybrid UCNPs/PSeV PS showed strong ROS generation ability and high photothermal conversion efficiency (∼52.5%) under the mildest reported-to-date irradiation conditions (λ = 980 nm, 150 mW/cm2, 4 min), leading to a high efficiency in killing methicillin-resistant Staphylococcus aureus (MRSA) both in vitro and in vivo. Remarkably, after intravenous injection, the reported PS accumulated preferentially in deep MRSA-infected tissues and achieved an excellent therapeutic index. This PS design realizes a low-power single-NIR light-triggered synergistic phototherapy and provides a simple and versatile strategy to develop safe clinically translatable agents for efficient treatment of deep tissue bacterial inflammations.

The development of novel applications of ultralong organic phosphorescent (UOP) materials is highly desired. Herein, a series of UOP materials (EDCz, E = O, S, Se, and Te) for bacterial afterglow imaging and photodynamic therapy (PDT) is reported. By structurally bonding with the chalcogen atoms with π-conjugated scaffolds, EDCz not only absorbs visible light but also emits UOP with an efficiency of ca. 0.01–6.8% and a long lifetime of 0.08–0.318 s under ambient conditions. Benefiting from the long-lived triplet excited states, the SeDCz nanocrystals (NCs) possessed the best optical properties in the series, generating 1O2 under white light irradiation and performing as an agent for Staphylococcus aureus afterglow imaging and PDT at a low concentration (98 ng mL–1). The SeDCz NCs are also utilized as real-time UOP imaging agents and promoted healing of infected wounds in living mice. To the best of our knowledge, this study presents the first example of UOP-based bacterial photodynamic theranostic agents and creates a platform for the next-generation efficient UOP-based photosensitizers for bioimaging and skin regeneration.

No abstract