Monica A. Serban

Cross-linked gelatin microspheres with continuously tunable degradation profiles for renal tissue regeneration

Collagen and gelatin‐based biomaterials are widely used in tissue engineering applications. Various methods have been reported for the cross‐linking of these macromolecules for the purpose of delaying their biodegradation to prolong their in vivo residence (in tissue engineering applications) or tailoring their drug releasing capacity (when used as drug carriers). In this study, a carbodiimide‐based cross‐linking method, also used in the production of United States Food and Drug Administration‐approved products, was employed to obtain differentially cross‐linked gelatin beads. The colorimetric determination of the in vitro enzymatic susceptibility of the beads indicated that the resistance to degradation linearly correlated with the concentration of carbodiimide used for the cross‐linking reaction. This result was also confirmed in vivo by the histological evaluation of the residence time of orthotopically injected cell‐seeded beads. These data would indicate that the production of gelatin‐based microbeads with tunable degradation profiles might be applicable toward the development of products that catalyze regeneration of kidney and other solid organs.

Translational biomaterials-the journey from the bench to the market-think 'product'.

Biomaterial research has been gaining popularity over the past decades and, in parallel, the number of biomaterial-based therapies has been increasing. There is still however, a disconnection between the number of developed biomaterials and those that make it to the market. In this context, a review of the biomaterial development trends in both industry and academia, specifically of biomaterials that were successfully translated from bench side to the clinic and the market, is warranted.

Preparation and Evaluation of Natural Scaffold Materials for Kidney Regenerative Applications

Tissue engineering involves the concerted action of biomaterials, cells, and growth factors. Kidney -regeneration relies on the same combination of ingredients. Here, we describe an example of gelatin-based biomaterial preparation and its evaluation in the context of kidney biocompatibility and integration. This biomaterial manufacturing technique is simple, cost-effective, highly reproducible and the in vivo evaluation procedure highly informative on the biocompatibility and regenerative potential of the tested construct.

A Controlled Antibiotic Release System for the Development of Single-Application Otitis Externa Therapeutics

Ear infections are a commonly-occurring problem that can affect people of all ages. Treatment of these pathologies usually includes the administration of topical or systemic antibiotics, depending on the location of the infection. In this context, we sought to address the feasibility of a single-application slow-releasing therapeutic formulation of an antibiotic for the treatment of otitis externa. Thixotropic hydrogels, which are gels under static conditions but liquefy when shaken, were tested for their ability to act as drug controlled release systems and inhibit Pseudomonas aeruginosa and Staphylococcus aureus, the predominant bacterial strains associated with outer ear infections. Our overall proof of concept, including in vitro evaluations reflective of therapeutic ease of administration, formulation stability, cytocompatibility assessment, antibacterial efficacy, and formulation lifespan, indicate that these thixotropic materials have strong potential for development as otic treatment products.

Hyaluronan chemistries for three-dimensional matrix applications

Hyaluronan is a ubiquitous constituent of mammalian extracellular matrices and, because of its excellent intrinsic biocompatibility and chemical modification versatility, has been widely employed in a multitude of biomedical applications. In this article, we will survey the approaches used to tailor hyaluronan to specific needs of tissue engineering, regenerative and reconstructive medicine and overall biomedical research. We will also describe recent examples of applications in these broader areas, such as 3D cell culture, bioprinting, organoid biofabrication, and precision medicine that are facilitated by the use of hyaluronan as a biomaterial.

Interplay between Silk Fibroin’s Structure and Its Adhesive Properties

Bombyx mori-derived silk fibroin (SF) is a well-characterized protein employed in numerous biomedical applications. Structurally, SF consists of a heavy chain (HC) and a light chain (LC), connected via a single disulfide bond. The HC sequence is organized into 12 crystalline domains interspersed with amorphous regions that can transition between random coil/alpha helix and beta-sheet configurations, giving silk its hallmark properties. SF has been reported to have adhesive properties and shows promise for development of medical adhesives; however, the mechanism of these interactions and the interplay between SFs structure and adhesion is not understood. In this context, the effects of physical parameters (i.e., concentration, temperature, pH, ionic strength) and protein structural changes on adhesion were investigated in this study. Our results suggest that amino acid side chains that have functionalities capable of coordinate (dative) bond or hydrogen bond formation (such as those of serine and tyrosine), might be important determinants in SFs adhesion to a given substrate. Additionally, the data suggest that fibroin amino acids involved in beta-sheet formation are also important in the proteins adhesion to substrates.

Nanoparticulate Poly(glucaramide)-Based Hydrogels for Controlled Release Applications

In 2004, d-Glucaric acid (GA) was identified as one of the top value-added chemicals from renewable feedstocks. For this study, a patented synthetic method was used to obtain gel forming polymers through the polycondensation of GA and several aliphatic diamines. The first time characterization and a potential practical application of such hydrogels is reported herein. Our findings indicate that the physical properties and gelling abilities of these materials correlate with the chemical structure of the precursor diamines used for polymerization. The hydrogels appear to have nanoparticulate nature, form via aggregation, are thermoresponsive, and appear suitable as controlled release systems for small molecules. Overall, this study further highlights the versatility of GA as a building block for the synthesis of sustainable materials, with potential for a wide array of applications.