Hydrogels are attractive materials for the controlled release of therapeutics because of their capacity to embed biologically active agents in their water-swollen network. Recent advances in organic and polymer chemistry, bioengineering and nanotechnology have resulted in several new developments in the field of hydrogels for therapeutic delivery. In this Perspective, we present our view on the state-of-the-art in the field, thereby focusing on a number of exciting topics, including bioorthogonal cross-linking methods, multicomponent hydrogels, stimuli-responsive hydrogels, nanogels, and the release of therapeutics from 3D printed hydrogels. We also describe the challenges that should be overcome to facilitate translation from academia to the clinic and last, we share our ideas about the future of this rapidly evolving area of research.

According to the International Energy Agency, biorefinery is “the sustainable processing of biomass into a spectrum of marketable bio-based products (chemicals, materials) and bioenergy (fuels, power, heat)”. In this review, we survey how the biorefinery approach can be applied to highly porous and nanostructured materials, namely aerogels. Historically, aerogels were first developed using inorganic matter. Subsequently, synthetic polymers were also employed. At the beginning of the 21st century, new aerogels were created based on biomass. Which sources of biomass can be used to make aerogels and how? This review answers these questions, paying special attention to bio-aerogels’ environmental and biomedical applications. The article is a result of fruitful exchanges in the frame of the European project COST Action “CA 18125 AERoGELS: Advanced Engineering and Research of aeroGels for Environment and Life Sciences”.

Hydrogels are three-dimensional, water-swollen polymer networks that have been widely studied for biomedical applications such as tissue engineering and the controlled delivery of biologically active agents. Since the pioneering work of Wichterle and Lim in the 1960s, hydrogel research has shifted from relatively simple single polymer networks to multifunctional composite hydrogels that better mimic the complex nature of living tissues. Bio-based polymers, which can be obtained from renewable natural resources, are attracting increasing attention for use in biomaterials due to the recent demands for a reduction in the environmental impact of the polymer industry and the development of a sustainable society. Moreover, bio-based polymers are often biodegradable and exhibit a significant level of biocompatibility and biomimicry, which are highly desired properties with regard to in vivo application. This review presents the state-of-the-art in the field of bio-based composite hydrogels for biomedical applications, thereby focusing on different types of polymeric components that have been combined with hydrogels to obtain materials with unique, synergistic properties: particles (including micelles and microspheres), electrospun fibres and nanocellulose. In addition, the challenges are described that should be overcome to facilitate clinical application of these versatile and environmentally responsible biomaterials.