Initiator-Free Photocuring 3D-Printable PVA-Based Hydrogel with Tunable Mechanical Properties and Cell Compatibility

α-Amylase and polydopamine@polypyrrole-based hydrogel microneedles promote wound healing by eliminating bacterial infection

In this paper, we designed a novel "Freeze-thaw" type hydrogel microneedle (PP-CDLut-AMY MN). The "Freeze-thaw" cycle endows the MN excellent water absorption, with a dissolution rate of up to 486 %. The addition of polydopamine@polypyrrole (PP) enabled the MN to have a stable temperature increase to approximately 50 °C under near-infrared light irradiation, which exhibited killing rates of 99 % and 98 % against free S. aureus and E. coli, respectively. Natural macromolecule α-Amylase (AMY) was used as a bacterial biofilm disintegrator, and the destruction rate of S. aureus biofilm reached 83.2 %. Meanwhile, the incorporation of Hydroxypropyl-β-cyclodextrin @Luteolin (CDLut) provided the MN with good antioxidant properties, which could scavenge 73.35 % of DPPH free radicals. In vivo experiments have shown that the MN can effectively promote the healing of wounds infected by S. aureus biofilm and that the stable and gentle photothermal effect did not cause unnecessary damage to the surrounding tissues. We believe that this novel hydrogel MN has great potential to combat bacterial biofilms associated with wound infections.

Research progress of photo-crosslink hydrogels in ophthalmology: A comprehensive review focus on the applications

Hydrogel presents a three-dimensional polymer network with high water content. Over the past decade, hydrogel has developed from static material to intelligent material with controllable response. Various stimuli are involved in the formation of hydrogel network, among which photo-stimulation has attracted wide attention due to the advantages of controllable conditions, which has a good application prospect in the treatment of ophthalmic diseases. This paper reviews the application of photo-crosslink hydrogels in ophthalmology, focusing on the types of photo-crosslink hydrogels and their applications in ophthalmology, including drug delivery, tissue engineering and 3D printing. In addition, the limitations and future prospects of photo-crosslink hydrogels are also provided.

Photocuring 3D Printing of Hydrogels: Techniques, Materials, and Applications in Tissue Engineering and Flexible Devices

Photocuring 3D printing of hydrogels, with sophisticated, delicate structures and biocompatibility, attracts significant attention by researchers and possesses promising application in the fields of tissue engineering and flexible devices. After years of development, photocuring 3D printing technologies and hydrogel inks make great progress. Herein, the techniques of photocuring 3D printing of hydrogels, including direct ink writing (DIW), stereolithography (SLA), digital light processing (DLP), continuous liquid interface production (CLIP), volumetric additive manufacturing (VAM), and two photon polymerization (TPP) are reviewed. Further, the raw materials for hydrogel inks (photocurable polymers, monomers, photoinitiators, and additives) and applications in tissue engineering and flexible devices are also reviewed. At last, the current challenges and future perspectives of photocuring 3D printing of hydrogels are discussed.

3D-Printed Liquid Metal-in-Hydrogel Solar Evaporator: Merging Spectrum-Manipulated Micro-Nano Architecture and Surface Engineering for Solar Desalination

Solar desalination driven by interfacial heating is considered a promising technique to alleviate the freshwater shortage crisis. However, its further extension and application are confined by factors such as highlighted salt accumulation, inferior energy efficiency, and poor durability. Herein, a microsized eutectic gallium-indium (EGaIn) core-shell nanodroplet (denoted as LMTE) with photo-cross-linking and photothermal traits, stabilized by allyl glycidyl ether (AGE)-grafting tannic acid (TA), is explored as the solar absorber for broadband light absorbing and localized micro-nano heat channeling. The LMTE nanodroplets are formulated directly with highly hydrated polymers and photosensitive species to successfully develop a water-based photothermal ink suitable for digital light processing (DLP) 3D printing. As a demonstration, the LMTE composite hydrogel-forged milli-conical needle arrays with metal-phenolic network (MPN)-engineered wettability and photothermal enhancement can be printed by the digital light processing (DLP) technique and designed rationally via a bottom-up strategy. The 3D-printing hydrogel evaporator is composed of spectrum-tailored EGaIn nanodroplets for efficient photon harvesting and MPN-coated milli-cone arrays for water supplying with micro-nano channeling, which function cooperatively to bestow the 3D solar evaporator with superior solar-powered water evaporation (2.96 kg m-2 h-1, 96.93% energy efficiency) and excellent solar desalination (salt cycle and site-specific salt crystallization). Furthermore, a robust steam generating/collecting system of the 3D solar evaporator is demonstrated, providing valuable guidance for building a water-energy-agriculture nexus.

Photo-Controllable Smart Hydrogels for Biomedical Application: A Review

Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo-controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.