Adipose stem cells controlled by surface chemistry.

This study investigated how human adipose stem cells (hASCs) could be influenced by surface chemistry. Self-assembled monolayers of alkanethiolates on gold were introduced as a surface chemistry model to provide a range of functional groups such as OH, COOH, NH₂, Phenyl, SH, Br, and CH₃ on surfaces. Initially, morphological changes of hASCs in response to different surface chemistries were observed with focal adhesion. Cell growth behaviour evaluated by Cell Counting Kit-8 (CCK8) assay (Dojindo Molecular Technologies Inc., Shanghai, China) and cytoskeletal F-actin Biochem Kit™ (Denver, CO, USA) staining revealed a descending order of growth rate on the following surfaces: NH₂  > SH > COOH > Phenyl > Br > OH > CH₃. The mRNA expressions of lineage specific markers including alkaline phosphatase (ALP), osteocalcin (OCN), type II collagen, aggrecan, peroxisome proliferator-activated receptor gamma (PPARγ), and fatty acid binding protein-2 (aP2), were determined using real-time reversed transcriptase-polymerase chain reaction (RT-PCR). Results revealed that NH₂ favoured hASC differentiation toward osteogenic, while phenyl and SH promoted chondrogenic differentiation of hASCs with a high level up-regulation of type II collagen and aggrecan. hASCs on Br increased in PPARγ and aP2 expression, indicating adipogenic differentiation. These results highlight the vital role of surface chemistry on the modulation of hASC differentiation and suggests chemical methods for designing biomaterials for stem cell-based tissue regeneration.