**5. Summary**

**Figure 5.** Study of aptamer ability to enhance the proliferation of murine osteoblastic cells (MC3T3-E1) on 2% chitosan films. Microphotographs, taken with an inverted microscope, showing MC3T3-E1 cells on 2% chitosan films after 48 h of culture and stained with the Trypan Blue to discriminate viable and dead cells. The rate of cell growth is proportion‐

In both the cases, aptamers increase the number of adhering cells and the rate of cell growth is proportional to the amount of aptamer used. Cell morphology appear round both in control groups and in aptamer-rich samples, unlike the flattened spindle shape morphology that is normally observed on tissue culture plastic substrates, and is routinely associated to firm cell adhesion. Although cell adhesion does appear improved in the presence of aptamers, as indicated by a significantly higher number of cells, the culture substrate is mechanically elastic

**Figure 6.** Histograms representing the amount of protein adsorbed on polymeric scaffolds with or without aptamers. Scaffolds were incubated for 2 h with 30 μg of proteins. The amount of protein bind by the scaffold was quantitated

Although aptamers act on both substrates presumably in comparable ways, by binding fibronectin, the rationale for their use is possibly different, as suggested by results of protein

and the normal morphological features of a good adhesion cannot be achieved.

al to the quantity of aptamer used for the functionalization (E).

344 Advanced Techniques in Bone Regeneration

through the Bradford.

Scaffolds for tissue engineering should support an appropriate cellular activity. In particular, cell adhesion and proliferation depend mainly on the efficiency of protein adsorption at the interface, a process deeply influenced by surface chemistry. Nowadays, a wide number of treatments have been proposed to enhance scaffold biocompatibility, including physical and chemical treatments or biological coatings. In this chapter we reported on the use of aptam‐ ers to improve scaffold biocompatibility.

After a general presentation on tissue engineering in Section 1, Section 2 described the rationale to control protein adsorption on biomaterial surfaces. A panoramic view of the methods developed and reported in literature to improve scaffold biocompatibility was reviewed. At the end of the section the possibility of using aptamers for this goal was outlined.

Section 3 contained general information about aptamers. The technique to obtain aptamers (SELEX) was well described and a general view on the use of aptamers in biomedical appli‐ cations was outlined. Finally, in Section 4 after the explanation of the rationale to use aptam‐ ers as enhancers for scaffold biocompatibility, our preliminary results were reported. In particular, we investigated the possibility to immobilize aptamers on different substrates to improve scaffold biocompatibility *in vitro*, with similar results. Aptamers were bound to tHA/ PEGDA hydrogels or to chitosan films: in both the cases the adsorption of proteins was ameliorated, as well as the adhesion and proliferation of cells. The results obtained paved the way to further investigation of the use of aptamers in combination with scaffolds for tissue engineering applications.
