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With the emergence of the coronavirus disease 2019 (COVID-19), the world is experiencing a profound human health crisis. The number of infections and deaths due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to increase every minute, pinpointing major shortcomings in our ability to prevent viral outbreaks. Although several COVID-19 vaccines have been recently approved for emergency use, therapeutic options remain limited, and their long-term potency has yet to be validated. Biomaterials science has a pivotal role to play in pushing the boundaries of emerging technologies for antiviral research and treatment. In this perspective, we discuss how biomaterials can be harnessed to develop accurate COVID-19 infection models, enhance antiviral drug delivery, foster new antiviral strategies, and boost vaccine efficacy. These efforts will not only contribute to stop or mitigate the current pandemic but will also provide unorthodox platforms to understand, prevent, and protect us from future viral outbreaks.

Over the past decade, electroconductive hydrogels, integrating both the biomimetic attributes of hydrogels and the electrochemical properties of conductive materials, have gained significant attention. Hydrogels, three-dimensional and swollen hydrophilic polymer networks, are an important class of tissue engineering (TE) scaffolds owing to their microstructural and mechanical properties, ability to mimic the native extracellular matrix, and promote tissue repair. However, hydrogels are intrinsically insulating and therefore unable to emulate the complex electrophysiological microenvironment of cardiac and neural tissues. To overcome this challenge, electroconductive materials, including carbon-based materials, nanoparticles, and polymers, have been incorporated within nonconductive hydrogels to replicate the electrical and biological characteristics of biological tissues. This review gives a brief introduction on the rational design of electroconductive hydrogels and their current applications in TE, especially for neural and cardiac regeneration. The recent progress and development trends of electroconductive hydrogels, their challenges, and clinical translatability, as well as their future perspectives, with a focus on advanced manufacturing technologies, are also discussed.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has led to an unprecedented global health crisis, resulting in a critical need for effective vaccines that generate protective antibodies. Protein subunit vaccines represent a promising approach but often lack the immunogenicity required for strong immune stimulation. To overcome this challenge, we first demonstrate that advanced biomaterials can be leveraged to boost the effectiveness of SARS‐CoV‐2 protein subunit vaccines. Additionally, we report that oxygen is a powerful immunological co‐adjuvant and has an ability to further potentiate vaccine potency. In preclinical studies, mice immunized with an oxygen‐generating COVID‐19 cryogel‐based vaccine (O2‐CryogelVAX) exhibited a robust Th1 and Th2 immune response, leading to a sustained production of highly effective neutralizing antibodies against the virus. Even with a single immunization, O2‐CryogelVAX achieved high antibody titers within 21 days, and both binding and neutralizing antibody levels were further increased after a second dose. Engineering a potent vaccine system that generates sufficient neutralizing antibodies after one dose is a preferred strategy amid vaccine shortage. Our data suggest that this platform is a promising technology to reinforce vaccine‐driven immunostimulation and is applicable to current and emerging infectious diseases. This article is protected by copyright. All rights reserved

Current healthcare practices often involve insertion of foreign devices into the body. Infections related to such devices or procedures pose a major threat to patient safety. As a result, there is an urgent need to develop technologies that better control healthcare-associated infections. In this regard, the latest innovations in hydrogel fabrication address some of these biomedical challenges. Particularly, hydrogels with antimicrobial characteristics have the remarkable potential to prevent or combat microbial infections. In this chapter, we review a number of promising strategies in the development of hydrogels with biocidal properties. First, common approaches are described for designing antimicrobial hydrogels. These techniques include using antimicrobic components such as bacteria-fighting polymers as well as encapsulating or conjugating agents that have antimicrobial functions with the gel. Next, various strategies and key factors relevant to the performance of antimicrobial hydrogels are detailed. Lastly, a comprehensive account of specific applications of antimicrobial hydrogels is provided, including implant coatings, contact lenses, wound dressings, and scaffolds for tissue reconstruction. The modular nature of antimicrobial hydrogel fabrication underscores their ability to address several biomedical challenges.

International audience; Biomaterial sterilization is a prerequisite prior to patient's use, especially for scaffold implantation or injection. Various sterilization processes are mandated by the Food and Drug Administration including high‐pressure steam sterilization. Although high‐pressure steam or autoclave sterilization eliminates pathogens, it often leads to irreversible damages on soft materials such as hydrogels. In the current study, the impact of autoclave sterilization on cryogels made from several naturally‐derived polymeric precursors (alginate, hyaluronic acid, and gelatin) is analyzed. Specifically, the impact of polymer concentration on the structural and physical properties of autoclaved cryogels such as mechanics, swelling ratio, pore interconnectivity, and shape‐memory features is studied. The results demonstrate that at a given optimal polymer concentration, unique for each biopolymer investigated, autoclave sterilization does not substantially alter the microarchitectural or physical characteristics of cryogels, including their syringe injectability signature. In summary, when formulated under optimized polymer concentrations, autoclavable cryogels hold great potential for several biomedical applications, as they can be easily translated into clinical practice to benefit public health.

Cryogenic processes are increasingly being utilized to create unique polymeric materials that tackle challenges mainly in the biomedical arena, environmental science, and field of food technology [...]

To prevent postoperative complications, there has been a substantial interest in designing syringe-injectable hydrogels. To date, cryogels remain the only viable option for preformed and large-scale hydrogels to be delivered through a conventional needle–syringe injection. Cryogels, a type of hydrogel with exceptional features, are fabricated at subzero temperatures. This process typically results in a biomaterial with a unique macroporous network, shape-memory properties, and exceptional flexibility allowing syringe injectability. These advanced biomaterials have been used for a number of biomedical applications, including tissue engineering, drug delivery, and more recently, immunotherapy. This review summarizes the recent progress on the design of injectable cryogels, their current limitations, and strategies to further improve their properties for translatability into the clinic.