PHOTOBIOMODULATORY EFFECT OF LOW-INTENSITY LASER RADIATION ON MULTICELLULAR SPHEROIDS

Photobiomodulatory effects of low-intensity laser radiation (LILR) in cells cultured in standard, two-dimensional conditions are well established. Conversely, the characteristics of this effect in three-dimensional (3D) cultures, which are currently recommended due to the greater similarity with cellular behavior in vivo, have not yet been widely investigated. The objective of this work was to analyze the biomodulator effect of LILR, on the wavelength (λ) of 685 nm, on the constitution process and on the viability of cells cultured as multicellular spheroid (MSs). For this, agarose molds containing microwells were seeded (2x105 cell/ml) with osteogenic precursor cells (OPCs - MC3T3-E1) and kept under ideal culture conditions. The molds were irradiated for five consecutive days with doses of 0.5, 1.0 and 1.5 J/cm², the first irradiation being performed immediately after sowing. The process of constitution of MSs was analyzed and the cultures were submitted to the cell viability test. The results demonstrated that the LILR at λ 685 nm exerted a dose-dependent biomodulatory effect on cell metabolism and on the process of constituting the MSs of OPCs. These results demonstrate the potential of photobiomodulation to contribute to the process of constituting MSs, which can be explored in the strategies of multicellular spheroids therapy used in regenerative medicine and bioprinting.

Electrospinning With Lyophilized Platelet-Rich Fibrin Has the Potential to Enhance the Proliferation and Osteogenesis of MC3T3-E1 Cells

Platelet-rich fibrin (PRF) as a reservoir of various growth factors plays an essential role in wound healing and tissue engineering at present. Electrospinning technology is an efficient approach to acquire artificial scaffold which has large specific surface area and high porosity. The goal of this study was to investigate the potential of electrospinning on the proliferation and osteogenesis of osteogenic precursor cells in vitro, with lyophilized PRF added as a component for electrospinning preparation. The surface structure of lyophilized PRF and nanofibers were investigated, and the proliferation, osteogenesis of MEC3T3-E1 cells with lyophilized PRF or nanofibers extract were studied. The results showed that the diameters of the lyophilized PRF pores were 1.51 ± 0.75 μm, and lyophilized PRF medium promoted the proliferation and osteocalcin (OCN) and osteopontin (OPN) genes expression of MEC3T3-E1 cells. Furthermore, the diameters of the polyvinyl alcohol/sodium alginate/lyophilized PRF (PVA/SA/PRF) fibers were 201.14 ± 40.14 nm. Compared to PVA/SA nanofibers extract and control medium, PVA/SA/PRF nanofibers extract also enhanced the proliferation and mineralization activity of MEC3T3-E1 cells. These results might be instructive to future therapeutics with PVA/SA/PRF electrospinning for bone tissue engineering or other applications.