Biomaterials and Bioanalogous Systems
A biomaterial, as defined by IUPAC, is a material exploited in contact with living tissues, organisms or microorganisms. Biomaterial science is a fast-growing field of multidisciplinary and collaborative research pushing forward concepts and practice. That is why the backbone of the Department is composed of researchers and PhD students with various backgrounds comprising organic chemistry, polymer chemistry and chemical engineering. Combination of these allows the Department to be involved in interdisciplinary projects combining chemical/material and biochemical/biological approaches with the understanding of mechanisms and interactions at biomaterial/cell interfaces.
The department researches the majority of the issues connected to biomaterials from their synthesis and physicochemical analysis to their applications. Namely, the Department deals with the design of polymer biomaterials and functional biomaterial interfaces aiming at the development of supporting structures (scaffolds) for regenerative medicine and tissue engineering. The primal research focus is on molecular cues, through which the communication between the biomaterial surface and biological systems, cells and living tissues can be controlled.
Research
Materials
The main materials used in the research are in-house synthesized fully biodegradable polymers derived either from poly(α-amino acid)s (polyAA), polypeptides, or aliphatic polyesters as well as biomimetic peptides that are able to control the interaction of biomaterials with cells or tissues. Natural polysaccharides such as alginate or hyaluronic acid and fully synthetic polymers such as poly(ethylene oxide), poly(hydroxyethyl methacrylate), and poly(methacrylamide)s are also utilized. The research activities of the Department focus on the following projects:
Biomimetic polymer surfaces for tissue engineering
Biomimetic surfaces were studied for selective support of different types of tissues (e.g. vascular, cartilage, bone, and neural) regeneration. The main concept is in the substrate-independent modification of the material surface with polydopamine-poly(ethylene oxide) protein repulsive layer followed by biomimetic modification. These modifications are performed using various micro/nanocontact printing or catalysis methods.
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3D scaffold fabrication
An integral part of the Department activity is the development of polymeric scaffolds for specific tissue engineering applications. For example, electrospun nanofibrous polylactide membranes used as a support for the cultivation and transplantation of retinal pigment epithelial cells are considered a promising treatment for degenerative retinal disorders.
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Furthermore, polylactide and polyAA are used for the preparation of the microfibrous discs scaffold applied for cartilage tissue engineering. Their optimized bioactivity, namely precisely controlled biomimetic peptide surface concentration, induced the differentiation of human tooth germ stem cells into chondrocytes
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Another example of scaffold development is the fabrication of covalently crosslinked cryogels suitable for the engineering of soft tissues. Synthesized at subzero temperatures by free-radical copolymerization of polyAA-based macromonomer with minor comonomers, they met the demands of high interconnected porosity and mechanical stability. The versatility of the cryogel composition allows them to be designed to be enzymatically degradable or/and to be able to undergo post-polymerization modifications with biomimetic peptides.
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Further promising approach for minimally invasive surgical tissue repair is in the use of injectable hydrogel scaffolds. For this project, enzymatically crosslinked injectable biodegradable hydrogels were obtained in situ from the poly(amino acid) precursor. Their different physicochemical properties like the gelation time, gel yield, swelling behavior, and storage modulus can be precisely tuned by varying the composition and concentration of the polymer precursors as well as the crosslinking enzyme concentration.
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Nanogels, or soft hydrogel nanoparticles, can be also used as injectable polymer scaffolds. In this case, the soft micro/nanogels were firstly prepared by enzymatic crosslinking in inverse mini-emulsion and then injected into animal models. Additionally, these materials can serve as biosensors as well as tools for the controlled release of bioactive molecules or (stem) cell delivery.
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3D printing
Lately, 3D printing emerged as one of the most promising ways of scaffold preparation. That is why our Department is currently working on the development of materials for advanced bioprinting. By integrating expertise in different areas of the research conducted by the Department, we can combine the advantages of fully non-xenogenic component based on synthetic poly(amino acids) with polysaccharide-based additives serving as porogens and nanogels as growth factor depots to design complex bioinks.
Microparticles for the drug delivery
Successful suppression of the immune response is vital during xeno-transplantations. It can be achieved by the controlled release of immunosuppression drugs (e.g. tacrolimus). In our group, biodegradable poly(D,L-lactide-co-glycolide) drug-loaded particles were developed for this purpose. These particles were successfully applied in various large animal model transplantation studies.
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Cooperation
- Yeditepe University, Department of Genetics and Bioengineering, Istanbul, Turkey
- Masaryk University, Department of Histology and Embryology, Faculty of Medicine, Brno, CZ
- Institute of Animal Physiology and Genetics, Academy of Sciences of the CR, Liběchov
- Vinohrady Teaching Hospital, Department of Ophthalmology, 3rd Faculty of Medicine, Charles University in Prague
- Stem Cell Therapies in Neurodegenerative Diseases, Spanish Stem CellBank, Centro de Investigación Príncipe Felipe, Valencia, Spain
- Department of Anesthesiology, University of California, San Diego, USA
- Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia
Funding Support
- Š. Popelka (co-investigator) Experimental transplantation of the retinal pigmented epithelial cells in a large animal model: CSF GA18-04393S (2018–2020)
- V. Proks Injectable polypeptide based hydrogels mimicking the dynamic processes in extracellular matrix: CSF GA18-03224S (2018–2020)
- V. Proks (co-investigator) Modelling lung tissue by 3D bioprinting of human progenitor cells: CSF GA18-05510S (2018–2020)
- V. Proks Xeno-free enzymatically degradable polymer materials for 4D bioprinting: CSF GA21-06524S (2021–2023)
- H. Studenovská (co-investigator) The establishment of advanced cell therapy for the treatment of limbal stem cell deficiency in the Czech Republic. TA ČR TO01000099 (2021–2023)
- H. Studenovská (co-investigator) Development of standardized culture, transplantation and banking of RPE cells for treatment of age-related macular degeneration (AMD) TA ČR TO01000107 (2021–2023)