Biomimetic Metallosaccharides—A New Material Class for Growing Artificial Cuticles for Biomedical and Food Safety Applications

In nature, the intricate interplay between organic and inorganic components often results in materials with exceptional properties. One such example is the cuticle of arthropods, where chitin, a polysaccharide, combines with proteins and minerals to form a robust, multifunctional exoskeleton. Inspired by these natural structures, we developed an approach to creating artificial cuticles with enhanced bioactivity.<br/>We have successfully developed and optimized a new strategy for growing coatings of artificial cuticles consisting of organic chitinoid and hybrid chitin-based films from the vapor phase using Molecular Layer Deposition (MLD). This innovative approach has led to the introduction of a new family of materials: metallochitins. These novel materials synergistically combine the properties of organic chitinoid polymers and inorganic metal oxides, exploiting a biomimetic approach to achieve unique functionalities.<br/>The synthesis of these metallochitin based artificial cuticles was accomplished through a solvent-free vapor-phase MLD process, coupling sugar-type monomers with metalorganics. This method allows for precise control over the composition and structure of the resulting hybrid films, enabling tailored properties for specific applications.<br/>We focused on two metallochitins: alumochitin and titanochitin. In vitro assessments of these materials against S. aureus and E. coli bacteria revealed strong antimicrobial properties, partly selective, ion dependence on the metal involved. The selectivity allows for designing specialized antimicrobial surfaces by optimizing various metal-saccharide combinations.<br/>Beyond their antimicrobial properties, we extensively investigated the biocompatibility of our artificial cuticles using human embryonic kidney (HEK293T) cells and human fibroblasts. Both alumochitin and titanochitin demonstrated excellent biocompatibility, promoting greater cell proliferation than reference coverslips. Notably, titanochitin outperformed pure titania in promoting HEK293T cell growth, suggesting a synergistic effect between the chitin and titanium components within the hybrid film. Conversely, fibroblasts showed a preference for aluminum-based surfaces. These findings highlight the potential to selectively regulate cell proliferation by manipulating surface charge and metal composition, underscoring the versatility of metallochitins as biomaterials.<br/>The dual functionality of our metallosaccharides - deterring bacterial adhesion while facilitating controlled cell growth - positions them as highly valuable materials for a wide range of applications. In the field of tissue engineering, these coatings could promote the growth of desirable cell types while preventing bacterial contamination, potentially revolutionizing the development of scaffolds and implants. For medical device fabrication, our metallochitins offer a promising solution to the persistent challenge of device-associated infections, potentially reducing the need for systemic antibiotics and improving patient outcomes. For food safety, these coatings could be applied to food processing equipment or packaging materials to inhibit bacterial growth and extend shelf life without compromising food quality.<br/>Thus, by drawing inspiration from nature and combining organic and inorganic components at the molecular level, we have created a versatile platform for multifunctional materials as artificial cuticles with tunable properties.