Promotion of initial cell adhesion on trisuccinimidyl citrate-modified nickel-free high-nitrogen stainless steel.

The surface of nickel-free high-nitrogen stainless steel (HNS) was modified with a citric acid-based cross-linker, trisuccinimidyl citrate (TSC), to promote initial cell adhesion in external skeletal fixation pins. The remaining active ester groups on TSC-immobilized HNS reacted with the amino groups of serum proteins. The immobilized serum proteins formed cell recognition sites to promote the initial cell adhesion immediately after cell seeding. The amount of fibronectin, which is a typical cell adhesion protein, immobilized on the TSC-immobilized HNS surface was threefold greater than on the original HNS after only 15 min. The fibroblastic cell culture experiments showed that the initial cell adhesion was significantly enhanced on the TSC-immobilized HNS compared with the original HNS at 3 h. Furthermore, the cell adhesion activity of the TSC-immobilized HNS continued to promote cell proliferation even at 7 days. Therefore, TSC-immobilized HNS may enable the rapid integration of soft tissues through its reaction with the patient's serum proteins and extracellular proteins around the surgical site.