Currently, a major challenge in material engineering is to develop a cell-safe biomaterial with significant utility in processing technology such as 3D bioprinting. The main goal of this work was to optimize the composition of a new graphene oxide (GO)-based bioink containing additional extracellular matrix (ECM) with unique properties that may find application in 3D bioprinting of biomimetic scaffolds. The experimental work evaluated functional properties such as viscosity and complex modulus, printability, mechanical strength, elasticity, degradation and absorbability, as well as biological properties such as cytotoxicity and cell response after exposure to a biomaterial. The findings demonstrated that the inclusion of GO had no substantial impact on the rheological properties and printability, but it did enhance the mechanical properties. This enhancement is crucial for the advancement of 3D scaffolds that are resilient to deformation and promote their utilization in tissue engineering investigations. Furthermore, GO-based hydrogels exhibited much greater swelling, absorbability and degradation compared to non-GO-based bioink. Additionally, these biomaterials showed lower cytotoxicity. Due to its properties, it is recommended to use bioink containing GO for bioprinting functional tissue models with the vascular system, e.g., for testing drugs or hard tissue models.

Background. Despite the wide range of diagnostic and therapeutic methods, breast cancer is responsible for many deaths each year. One of the original and novel cancer therapeutic approaches is gene therapy based on recombinant adeno-associated viral vectors. Among the molecular factors with the potential to become useful diagnostic biomarkers, microRNA (miRNA) molecules are being considered for personalized therapies. Objectives. The aim of the study was to examine the utility of miRNA profiling in the design of personalized recombinant adeno-associated virus (rAAV)-based gene therapy for breast cancer patients. Materials and methods. The analysis of 754 miRNAs in 7 breast cancer samples and control samples was performed using real-time polymerase chain reaction (PCR) based on TaqMan (R) Low-density Array (TLDA) cards. Online repositories were used to explore the relationship between miRNAs and genes encoding rAAV receptors (KIAA0319L, HSPG2, FGFR1, c-MET, PDGFRA, ITGB5, and RPSA). Then, we performed a comparative analysis of the results to examine the possibility of using miRNA profiling in the design of rAAV-based therapeutic protocols. Results. Fifty-two percent of tested miRNAs were noted in at least 1 analyzed breast cancer and control tissue. Thirteen miRNAs were selected due to being outliers in the tested samples. In total, 155 miRNAs targeted genes encoding rAAV receptors in the tested samples (29 miRNAs for KIAA0319L, 60 miRNAs for c-MET, 31 miRNAs for HSPG2, 43 miRNAs for FGFR1, 36 miRNAs for PDGFRA, 18 miRNAs for RPSA, and 25 miRNAs for ITGB5). The expression of the selected miRNAs was not homogeneous across the 7 samples. Conclusions. Profiling of microRNA could be a significant factor in the design of rAAV-based personalized gene therapy for breast cancer patients.