Biomolecules are a group of organic entities that are important in many areas of research on nanomaterials and for biomedical and pharmaceutical applications. Advanced systems have been developed to attempt to protect the activity of biomolecules from rapid degradation and instability. Among these techniques, the incorporation or immobilization of biomolecules has become popular in the development of biocomposites. As such, clay minerals appear to be promising materials; combining a nanometer-scale size with their adsorptive capacity, lack of toxicity, and biocompatibility would result in enhanced biomaterial properties. This mini‑review discusses the recent advances concerning biological molecules immobilized on clay minerals and their biomedical applications as biosensors, in regenerative medicine, and even as controlled delivery systems.

The respiratory protection equipment (RPE) used by health professionals consists of an essential device to prevent infectious diseases, especially those caused by biological agents such as the coronavirus (SARS-CoV-2). The current epidemiological panorama is worrying, and the context of creation and production of the mask has emerged as an alternative to RPE to face the public health crisis worldwide. The aim of this work is to present a low-cost alternative as an FFP2-like filter for a reusable respirator face mask. This study presents the comparison of different cellulose-based filtering materials performed by retention testing, time saturation testing, aerosol penetration testing, nanoparticle (~140 nm) filtration testing, bacterial filtration efficiency (BFE), analysis of material morphology and usability. The reusable respirator face mask used in this study is an open-source innovation, using 3D printing. Cotton disc proved to be the best filter material for the reusable mask, with satisfactory results and a performance similar to that shown by the N95-type mask. The cotton disc ensured effectiveness over 6 h of use, and after that, the reusable respirator face mask (here, Delfi-TRON®) needed to be sanitized and replenished with a new cotton disc. Upon preliminary analyses of filtration efficiency, the selected filter was shown to be a low-cost biodegradable and biocompatible alternative.