Bacterial cellulose (BC) is a nanocellulose form produced by some nonpathogenic bacteria. BC presents unique physical, chemical, and biological properties that make it a very versatile material and has found application in several fields, namely in food industry, cosmetics, and biomedicine. This review overviews the latest state‐of‐the‐art usage of BC on three important areas of the biomedical field, namely delivery systems, wound dressing and healing materials, and tissue engineering for regenerative medicine. BC will be reviewed as a promising biopolymer for the design and development of innovative materials for the mentioned applications. Overall, BC is shown to be an effective and versatile carrier for delivery systems, a safe and multicustomizable patch or graft for wound dressing and healing applications, and a material that can be further tuned to better adjust for each tissue engineering application, by using different methods.

No abstract

Biopolymeric patches show enormous potential for the regeneration of infarcted myocardium tissues. However, most of them usually lack appropriate mechanical performance, stability in water, and important functionalities; for instance, antioxidant activity. Protein nanofibrils, such as lysozyme nanofibrils (LNFs), are biocompatible nanostructures with excellent mechanical performance, water insolubility, and antioxidant activity exploited to fabricate materials for different biomedical applications. In this study, LNFs are used to produce gelatin electrospun nanocomposite cardiac patches with improved properties. The addition of the LNFs to the gelatin electrospun patches enhance their mechanical properties, increasing the patches Young's modulus from 3 to 6 MPa, in their wet state, which agrees with the requirements of myocardial contractility. Additionally, it is observed an increment of the antioxidant activity to 80%, by adding only 5% (w/w) of LNFs, and the bioresorbability rate is shortened to 30-35 d, compared to 45 d for the gelatin-only patches, while maintaining their morphology, and biocompatibility toward cardiomyoblasts and fibroblasts. Furthermore, 15% of a model drug is burst released from the patches and preserved for 21 d. Overall, these results demonstrate that LNFs have a great potential as functional reinforcements to fabricate biopolymeric electrospun patches for myocardial infarcted tissue regeneration.

A linear decapeptide containing three His and one Asp residues and a β-turn-inducing dProPro unit was synthesised. A detailed potentiometric, mass spectrometric and spectroscopic study showed that at a 1:1 ratio of CCu /Cpeptide this peptide formed a major [CuH(O(dPro)-Asp)](2+) species (pH range 5.5-7.0), in which the Cu(2+) ion was bound to the His and Asp residues in square-planar or square-pyramidal geometries. The stability constant corrected for protonated species (log K* CuH(O dPro-Asp)=9.33) is almost equal to the value obtained for the parent [CuH(OAsp)](2+) species (log K*CuH(O-Asp) =9.28), but lower than that obtained for the cyclic [CuH(C-Asp)](2+) complex (log K*CuH(C-Asp) =10.79) previously published. Thus, the replacement of the ProGly unit by the stronger β-turn-inducing dProPro unit did not generate a more stable copper(II) species, although the O(dPro)-Asp peptide was structured in solution, as shown by circular dichroism (CD) spectroscopy. Interestingly, the calculated value of Keff showed that this peptide behaved similarly to the O-Asp or C-Asp counterparts, depending on the pH value. The cyclic voltammetry data indicated that the most easily reducible species were [CuH(O-Asp)](2+) (E'(0) =262 mV versus a normal hydrogen electrode (NHE)) and [CuH(O(dPro)-Asp)](2+) (E'(0) =294 mV versus NHE) complexes, the peptidic scaffolds of which are open. A lower value was obtained for [CuH(C-Asp)](2+) (E'(0) =24 mV versus NHE). A different degree of non-reversibility was observed for the three copper(II) complexes; this could reflect a different degree of flexibility in their respective peptidic scaffolds.