Biomineralization-Inspired Intermediate Precursor for the Controllable Gelation of Polyphenol-Macromolecule Hydrogels

Natural small molecule-based recoverable polymer binders for intact and efficient recycling of lithium-ion batteries

As an indispensable part of the battery, the binder plays an important role in maintaining the structural integrity of the battery electrode and improving its electrochemical performance. Conventional polyvinylidene fluoride (PVDF) binders are particularly difficult to remove during the recycling of waste batteries because of their strong chemical stability, which not only markedly increases the recycling cost but also generates a large amount of fluorine-containing waste gas that pollutes the environment. In this study, a recoverable polymer binder (LM) with excellent self-healing properties, adhesion, and long-lasting stability was prepared for lithium-ion batteries using a simple heating polymerization method based on the natural small molecule α-lipoic acid (LA). The batteries assembled with LM exhibited excellent long-term stable performance at a high rate. After 920 cycles of charging and discharging at 1.0 C, the specific capacity was maintained at 80 %, while the battery assembled with PVDF only provided 524 cycles under the same conditions. More importantly, LM can be easily removed using a pH-control method to realize intact and efficient recycling of lithium iron phosphate (LFP) active material. This strategy opens a new path for the efficient recycling of large-scale energy storage batteries.

Protein-polysaccharide based nanogel/hydrogel composite with controlled continuous delivery of drug for enhanced wound healing

In the development of drug delivery vehicles for full-thickness skin wounds, achieving a specific drug concentration at the active site remains a key challenge. In this work, we reported a novel protein-polysaccharide bio-based composite hydrogel (SG@CRG) with controlled continuous drug delivery for enhanced wound healing. This composite hydrogel was prepared by incorporating drug embedded spirulina protein isolate nanogels (SG) into carboxymethyl chitosan based hydrogel (CRG) network, which exhibited rapid gelation and excellent mechanical properties. Notably, the release rate of the embedded drug could be tuned by adjusting the proportion of SG within the composite hydrogels. In vitro experiments demonstrated that the composite hydrogel exhibited excellent antibacterial activity against both gram-positive and gram-negative bacteria (inhibition rates at 12 h for S. aureus and E. coli were 99.77 % and 98.64 %, respectively), and good biocompatibility. Additionally, the hydrogel could effectively alleviate excessive inflammation and oxidative stress damage. Lastly, a full-thickness mouse skin model was established to assess its wound healing performance in vivo, which found that the composite hydrogel markedly accelerated wound healing (the healing ratios achieved by day 7 and day 12 were 78.37 % and 99.13 %, respectively, compared to 56.99 % and 84.50 % in the control group) by diminishing inflammation, promoting granulation tissue regeneration, increasing collagen deposition, and accelerating angiogenesis. Altogether, this innovative protein-polysaccharide bio-based composite hydrogel provides new insights and technical support for the development of more efficient wound treatment method, showing its potential application as a wound healing drug delivery vehicle.

Plant Polyphenol-Based Injectable Hydrogels: Advances and Biomedical Applications

Plant polyphenol-based hydrogels, known for their biocompatibility and adhesive properties, have emerged as promising materials in biomedical applications. These hydrogels leverage the catechol group's ability to form stable bonds in moist environments, similar to mussel adhesive proteins. This review provides a comprehensive overview of their synthesis, adhesion mechanisms, and applications, particularly in wound healing, tissue regeneration, and drug delivery. However, challenges related to in vivo stability and long-term biocompatibility remain critical barriers to clinical translation. Future research should focus on enhancing the bioactivity, biocompatibility, and scalability of these hydrogels, while addressing concerns related to toxicity, immune responses, and large-scale manufacturing. Advances in artificial intelligence-assisted screening and 3D/4D bioprinting are expected to accelerate their development and clinical translation. Furthermore, the integration of biomimetic designs and responsive functionalities, such as pH or temperature sensitivity, holds promise for further improving their therapeutic efficacy. In conclusion, the development of multifunctional plant polyphenol-based hydrogels represents a promising frontier in advancing personalized medicine and minimally invasive treatments.

Molecular Packing-Driven Manipulation of Aggregation Induced Emission in Gold Nanoclusters

A key limitation of supramolecular force-driven molecular assembly in aggregation-induced emission (AIE) materials is the need to precisely regulate molecular interactions within the assembly. Achieving such assemblies with in situ manipulable molecular arrangements could provide valuable insights into the role of molecular forces in AIE. Herein, by using glutathione-protected gold nanoclusters (AuNCs) as a model AIE material and a naturally occurring polyphenol, tannic acid (TA), as the assembling agent, we demonstrate that assemblies dominated by covalent bonds and hydrogen bonding show enhanced AIE, while those dominated by π-π stacking promote charge transfer, resulting in significant photoluminescence (PL) quenching. This phenomenon primarily stems from the oxidation of TA into smaller aromatic ring structures, leading to an increase in π-π interactions. The complete in situ oxidation of TA within the assembly induces a morphological transition from 3-D spherical to 2-D sheet-like structures due to the dominance of π-π interactions, consequently resulting in complete PL quenching of AuNCs. These findings highlight the critical role of molecular packing in modulating the AIE properties of AuNCs.

Natural Underwater Bioadhesive Offering Cohesion Modulation via Hydrogen Bond Disruptor: A Highly Injectable and in Vivo Stable Remedy for Gastric Ulcer Resolution

Injectable bioadhesives are attractive for managing gastric ulcers through minimally invasive procedures. However, the formidable challenge is to develop bioadhesives that exhibit high injectability, rapidly adhere to lesion tissues with fast gelation, provide reliable protection in the harsh gastric environment, and simultaneously ensure stringent standards of biocompatibility. Here, a natural bioadhesive with tunable cohesion is developed based on the facile and controllable gelation between silk fibroin and tannic acid. By incorporating a hydrogen bond disruptor (urea or guanidine hydrochloride), the inherent network within the bioadhesive is disturbed, inducing a transition to a fluidic state for smooth injection (injection force <5 N). Upon injection, the fluidic bioadhesive thoroughly wets tissues, while the rapid diffusion of the disruptor triggers instantaneous in situ gelation. This orchestrated process fosters the formed bioadhesive with durable wet tissue affinity and mechanical properties that harmonize with gastric tissues, thereby bestowing long-lasting protection for ulcer healing, as evidenced through in vitro and in vivo verification. Moreover, it can be conveniently stored (≥3 m) postdehydration. This work presents a promising strategy for designing highly injectable bioadhesives utilizing natural feedstocks, avoiding any safety risks associated with synthetic materials or nonphysiological gelation conditions, and offering the potential for minimally invasive application.

Injectable hydrogels as emerging drug-delivery platforms for tumor therapy

Tumor therapy continues to be a prominent field within biomedical research. The development of various drug carriers has been propelled by concerns surrounding the side effects and targeting efficacy of various chemotherapeutic drugs and other therapeutic agents. These carriers strive to enhance drug concentration at tumor sites, minimize systemic side effects, and improve therapeutic outcomes. Among the reported delivery systems, injectable hydrogels have emerged as an emerging candidate for the in vivo delivery of chemotherapeutic drugs due to their minimal invasive drug delivery properties. This review systematically summarizes the composition and preparation methodologies of injectable hydrogels and further highlights the delivery mechanisms of diverse drugs using these hydrogels for tumor therapy, along with an in-depth discussion on the optimized therapeutic efficiency of drugs encapsulated within the hydrogels. The work concludes by providing a dynamic forward-looking perspective on the potential challenges and possible solutions of the in situ injectable hydrogels for non-surgical and real-time diagnostic applications.

Self-Powered, Non-Toxic, Recyclable Thermogalvanic Hydrogel Sensor for Temperature Monitoring of Edibles

Thermogalvanic hydrogel, an environmentally friendly power source, enable the conversion of low-grade thermal energy to electrical energy and powers microelectronic devices in a variety of scenarios without the need for additional batteries. Its toxicity, mechanical fragility and low output performance are a hindrance to its wide application. Here, we demonstrate thermoelectric gels with safe non-toxic, recyclable, highly transparent and flexible stretchable properties by introducing gelatin as a polymer network and SO3/42- as a redox electric pair. When the temperature difference is 10 K, the gel-based thermogalvanic cell achieves an open-circuit voltage of about 16.2 mV with a maximum short-circuit current of 39 μA. Furthermore, we extended the application of the Gel-SO3/42- gel to monitor the temperature of hot or cold food, enabling self-powered sensing for food temperature detection. This research provides a novel concept for harvesting low-grade thermal energy and achieving safe and harmless self-driven temperature monitoring.