Anti-fibronectin aptamers improve the colonization of chitosan films modified with D-(+) Raffinose by murine osteoblastic cells

The aim of the present study was to investigate how the enrichment of chitosan films with anti-fibronectin aptamers could enhance scaffold colonization by osteoblasts, by improving their adhesion and accelerating their proliferation. Chitosan discs were enriched with excess of anti-fibronectin aptamer. Aptamer adsorption on chitosan was monitored by measuring aptamer concentration in the supernatant by spectrophotometry, as well as its release, while functionalization was confirmed by labelling aptamers with a DNA intercalating dye. Chitosan samples were then characterized morphologically with atomic force microscopy and physically with contact angle measurement. Chitosan enrichment with fibronectin was then investigated by immunofluorescence and Bradford assay. 2% chitosan discs were then enriched with increasing doses of aptamers and used as culture substrates for MC3T3-E1 cells. Cell growth was monitored by optical microscopy, while cell viability and metabolic activity were assessed by chemiluminescence and by Resazurin Sodium Salt assay. Cell morphology was investigated by cytofluorescence and by scanning electron microscopy. Chitosan films efficiently bound and retained aptamers. Aptamers did not affect the amount of adsorbed fibronectin, but affected osteoblasts behavior. Cell growth was proportional to the amount of aptamer used for the functionalization, as well as aptamers influenced cell morphology and their adhesion to the substrate. Our results demonstrate that the enrichment of chitosan films with aptamers could selectively improve osteoblasts behavior. Furthermore, our results support further investigation of this type of functionalization as a suitable modification to ameliorate the biocompatibility of biomaterial for hard tissue engineering applications. Graphical abstract: