Investigação do comportamento celular em ambientes poliméricos biocompatíveis e microestruturados por litografia 3D multifotônica

Abstract

The two-photon polymerization (2PP) additive technique has emerged as an excellent method for three-dimensional (3D) microfabrication among the many existing processes, enabling the construction of 3D microstructures with high spatial resolution at the submicrometer scale, complex geometric designs, and minimal use of photosensitive materials. This powerful tool has drawn the interest of various scientific fields, including tissue engineering, with applications in the fabrication of three-dimensional scaffolds for cell culture. These microenvironments are designed to mimic in vivo conditions, replicating their key features to enable the study of cellular behavior and the treatment of diseases through drug testing.Photosensitive resins serve as the raw material for the construction of scaffolds, and although there is a wide range of these materials available for biological studies, there is a significant focus on ensuring their biocompatibility and low cytotoxicity. The objective of this study was to investigate the effect of microgroove-type scaffolds with different geometries on the cellular elastic modulus, propose an efficient surface treatment method for polymeric substrates to enhance cell adhesion, and synthesize biocompatible, antibacterial, and flexible nanocomposites for tissue engineering applications. The results demonstrated that all synthesized resins exhibited acceptable biocompatibility. Notably, the sample containing titanium dioxide (TiO2) nanocrystals showed low cytotoxicity and a high cell proliferation rate, which remained superior to the control for up to 48 hours. The biomechanical properties of osteoblast cells in direct contact with circular scaffolds exhibited a significantly higher Young’s modulus (22.66±6.62 MPa) compared to cells seeded on rectangular scaffolds and flat surfaces, which displayed values of 13.79±2.54 MPa and 18.27±3.31 MPa, respectively. Optical and spectroscopic observations revealed that it is possible to regulate the physicochemical properties—including moderate roughness, increased hydrophilicity, and the formation of functional groups on polymeric substrates treated with phosphate-buffered saline (PBS)—to improve the adhesion of pulmonary epithelial cells. Additionally, the polymer functionalized with red propolis nanoparticles (RP NPs) exhibited a significant antibacterial effect against S. aureus. This effect was attributed to the presence of phenolic compounds in the polymeric samples, confirmed by Fourier-transform infrared (FTIR) spectroscopy. Finally, the scaffolds with parallel and circular microgrooves fabricated via 2PP demonstrated potential for the controlled release of RP NPs, indicating significant applicability in wound healing processes.