Design of Sustainable Mussel-Inspired Functional (Nano)Materials through Enzymatic Approaches

Description

Bringing nature as a source of endless inspiration for the development of promising classes of sustainable (nano)materials and hydrogels, a strong emphasis has been given on the latest advances for their design and production, aiming to obtain outstanding biological characteristics as the natural counterpart. Polydopamine (PDA), a bioinspired polymer from mussel adhesive proteins, has attracted relevant attention as a novel coating of (nano)materials with an adequate conformal layer and adjustable thickness and as mussel-inspired hydrogels with spectacular stretchable, bioadhesive properties, improved mechanical properties, and functionality. Due to their deposition simplicity and beneficial interaction with biomolecules and cells, and water-insolubility, the main application of PDA based-materials and hydrogels is undeniable in the biomedical sector. Some examples and main advantages include: Implantable Devices (Enhanced biocompatibility, reduced infection risk, and improved integration with host tissues); Drug Delivery Systems (Controlled release of therapeutic agents and improved targeting); Tissue Engineering (Improved cell adhesion, proliferation, and differentiation on scaffolds); Biosensors (Enhanced sensitivity and specificity for diagnostic applications); Antimicrobial Surfaces (Reduced bacterial adhesion and biofilm formation on medical devices) and Wound Healing (Antibacterial properties, improved mechanical strength, and controlled release of growth factors or drugs). Currently, PDA is obtained by dopamine (DA) chemical oxidation at alkaline conditions, limiting its use in materials or hydrogels sensible to alkaline environments. Envisaging a widespread use of PDA, this project aims the development of an alternative route for DA polymerization. The diphenolic structure of DA makes laccase a potential biocatalyst for its oxidative polymerization in a large range of pHs, overcoming thus the limitations of the chemical oxidation relative to pH high values. However, the main bottleneck of laccase-based biocatalytic processes is the associated high cost of the enzyme. The laccase production from recombinant microorganisms can be considered the best strategy to overcome these disadvantages, since efficient production and simple extraction of this costly biocatalyst can become possible, while maintaining, or even enhancing its catalytic activity and productivity. So, extraction and purification of laccase from fermentations will be developed using liquid-liquid extraction (LLE), namely by applying aqueous biphasic systems (ABS). In parallel, a new sustainable integrated platform, with focus on enzymatic PDA production and on ABS for enzyme extraction, recycling and reuse will be also developed. The purified laccase will be used in the polymerization of DA. Carbon-based materials (carbon nanotubes, graphenes and carbon xerogels), natural materials (chitosan and collagen) and polymeric materials (polyilatic acid and polyglycolic acid and polyurethane) and the respective chitosan- and collagen-based hydrogels will be explored as support matrices for PDA coating. The functionalization of the materials will be evaluated and will consist mainly in surface modifications based on the introduction of specific functional groups. Insitu and exsitu materials coating by enzymatic polymerization of DA into PDO, coating contact time between PDA and material, pH, temperature and enzyme concentration will be evaluated. The materials produced will be characterized in terms of thickness of the PDA film, surface charge, porosity and surface area and chemical and structural characteristics. This BioMussel exploratory project brings together a multidisciplinary team of researchers and students, promoting knowledge exchange and accelerating the development of innovative, cost-effective, and environmentally friendly PDA-based materials. This project will contribute to the process intensification and development of innovative and cost-effective and environmentally friendly high-quality PDA-based materials, which will certainly alleviate health, economic, social and environmental burdens.