# Hydroxyapatite-Complexed Type I Collagen and Fibrinogen-Modified Porous Titanium Alloy Scaffold: Promoting Osteogenesis and Soft Tissue Integration

## TL;DR

This paper introduces a modified titanium alloy scaffold that promotes bone and soft tissue growth for better medical applications.

## Contribution

A novel composite coating using hydroxyapatite, collagen, and fibrinogen on titanium scaffolds is developed to enhance osteogenesis and tissue integration.

## Key findings

- The composite coating shows excellent stability and biocompatibility in vitro.
- Preosteoblasts and keratinocytes exhibit improved adhesion and proliferation on the modified scaffolds.
- The scaffold demonstrates significantly enhanced osteogenic performance.

## Abstract

Titanium and its alloy scaffolds are widely utilized in clinical settings; however, their biologically inert surfaces and inherent mechanical characteristics impede osteogenesis and soft tissue integration, thereby limiting their application. Selective laser melting (SLM) was employed to fabricate scaffolds with matched cortical bone mechanical properties, achieving a composite coating of hydroxyapatite complexed with trace elements of silicon, strontium, and fluoride (mHA), along with type I collagen (Col I) and fibrinogen (Fg), thus activating the scaffold surface. Initially, we utilized the excellent adhesive properties of dopamine to co-deposit mHA and polydopamine (PDA) onto porous Ti-6Al-4V scaffolds, which was followed by immobilization of type I collagen and fibrinogen onto PDA. This bioinorganic/bioprotein composite coating, formed via PDA bonding, exhibits excellent stability. Moreover, in vitro cell experiments demonstrate excellent biocompatibility of the porous Ti-6Al-4V scaffold with composite bioactive coatings on its surface. Preosteoblasts (MC3T3-E1) and human keratinocytes (HaCaT) exhibit enhanced adhesion and proliferation activity, and the osteogenic performance of the scaffold is significantly improved. The PDA-mHA-Col I-Fg composite-coated porous titanium alloy scaffold holds significant promise in enhancing the efficacy of percutaneous bone transplantation and requires further investigation.