Proliferation and stemness preservation of human adipose-derived stem cells by surface-modified in situ TiO2 nanofibrous surfaces

Abstract

Two important criteria of an ideal biomaterial in the field of stem cells research are to regulate the cell proliferation without the loss of its pluripotency and to direct the differentiation into a specific cell lineage when desired. The present study describes the influence of TiO 2 nanofibrous surface structures on the regulation of proliferation and stemness preservation of adipose-derived stem cells (ADSCs). TiO 2 nanofiber arrays were produced in situ onto Ti-6Al-4V substrate via a thermal oxidation process and the successful fabrication of these nanostructures was confirmed by field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and contact angle measurement. ADSCs were seeded on two types of Ti-6Al-4V surfaces (TiO 2 nanofibers and flat control), and their morphology, proliferation, and stemness expression were analyzed using FESEM, AlamarBlue assay, flow cytometry, and quantitative real-time polymerase chain reaction (qRT-PCR) after 2 weeks of incubation, respectively. The results show that ADSCs exhibit better adhesion and significantly enhanced proliferation on the TiO 2 nanofibrous surfaces compared to the flat control surfaces. The greater proliferation ability of TiO 2 nanofibrous surfaces was further confirmed by the results of cell cycle assay. More importantly, TiO 2 nanofibrous surfaces significantly upregulate the expressions of stemness markers Sox-2, Nanog3, Rex-1, and Nestin. These results demonstrate that TiO 2 nanofibrous surfaces can be used to enhance cell adhesion and proliferation while simultaneously maintaining the stemness of ADSCs, thereby representing a promising approach for their potential application in the field of bone tissue engineering as well as regenerative therapies.

Efficient generation of smooth muscle cells from adipose‐derived stromal cells by 3D mechanical stimulation can substitute the use of growth factors in vascular tissue engineering

“…However, in the current study we show that stimulation of ASC with only TGF-β1 increases the expression of α-SMA, SM22α and calponin and that the resulting SMC are contractile too. It has been shown that culture substrates can influence cell function and differentiation capacity [33][34][35][36][37][38]. However, ASC cultured on TCPS, glass and PTMC all differentiated towards SMC after one week of stimula- Figure 5.…”

Applications of nanomaterials in mechano-sensitive tissues

“…The modified fibres supported MG-63 osteoblast proliferation, penetration and ECM deposition [59]. Titanium dioxide (TiO2) nanofibrous scaffolds demonstrated better cell adhesion and proliferation compared to the flat control surfaces using cell cycle analysis [60]. Expression of stemness markers genes including Nanog3, Rex-1, SOX-2 and nestin of the ADSCs cultured on the control and TiO2 nanofibrous surfaces was also higher on the fibrous surfaces than controls surfaces [60].…”

“…To support tissue formation, it has been extensively popular to load nanofibres with bioactive factors to modify the cell environment and mimic the natural ECM niche. Biofactors can be loaded onto nanofibres using several techniques including blending, coaxial spinning and immobilization [60][61][62][63]. Blending of the desired factors during electrospining can lead to aggregation homogenous dispersion along the fibres [60][61][62][63].…”

“…Coaxial electrospining causes the factor to localize to the center of the fibre. This is where two solutions are pumped though needles or cylinders and then electrospun to create a fibre [60][61][62][63]. Two solutions have different solubility, which prevents the mixing of the fibres during the electrospining process.…”

“…Two solutions have different solubility, which prevents the mixing of the fibres during the electrospining process. Lastly, the factor of interest can be adhered or immobilised onto the nanofibre surface using techniques such as chemical functionalization or self assembly [60][61][62][63].…”