Improving Hydrophilicity and Inducing Bone-Like Apatite Formation on PPBES by Polydopamine Coating for Biomedical Application

Abstract

Copoly(phthalazinone biphenyl ether sulfone) (PPBES) as a commercially available polyarylether is a promising orthopaedic implant material because its mechanical properties are similar to bone. However, the bioinert surface of polyarylether causes some clinical problems after implantation, which limits its application as an implant material. In this study, the surface of PPBES was modified by a biomineralization method of polydopamine-assisted hydroxyapatite formation (pHAF) to enhance its cytocompatibility. Polydopamine (PDA) coating, inspired by the adhesion mechanism of mussels, can readily endow PPBES with high hydrophilicity and the ability to integrate via the bone-like apatite coating. PPBES and PDA-coated PPBES were evaluated by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurement. The water contact angles were reduced significantly after coating with PDA. PDA was successfully synthesized on PPBES and more PDA was obtained by increasing the temperature. Bone-like apatite on PPBES (apatite-coated PPBES) was confirmed by SEM and transmission electron microscopy (TEM). The cytotoxicity of pristine PPBES and apatite-coated PPBES were characterized by culturing of NIH-3T3 cells. Bone-like apatite synthesized by pHAF could further enhance cytocompatibility in vitro. This study provides a promising alternative for biofunctionalized PPBES with improved cytocompatibility for bone implant application.

Strategies for Using Polydopamine to Induce Biomineralization of Hydroxyapatite on Implant Materials for Bone Tissue Engineering

“…The modified PPBES demonstrated low cytotoxicity (almost negligible) to NIH-3T3 cell lines, while cell adhesion was increased by 1.2-fold as detected by scanning electron microscopy. The results open a new approach for surface modification of poly(aryl ether) derivatives to extend their application in bone tissue engineering [ 68 ]. The pHAF was also applied in a PCL scaffold to obtain highly osteoinductive implantation composite (PCL-PDA-HA).…”

Construction of a BMP‐2 gene delivery system for polyetheretherketone bone implant material and its effect on bone formation in vitro

“…For instance, Liu reported that the hemispherical apatite particles adhered to the PDA-coated PPBES surface, while pure PPBES group did not facilitate apatite formation. 25 On this basis, the NPEEK-PDA-(PLGA-NH 2 @pBMP-2) group had more positive ALP activity or calcium deposition. With the degradation of PLGA on the scaffold, it provided space for bone tissue repair and supported bone conduction, meanwhile pBMP-2 could persist in playing a role at the cell-implant interface, and the proliferated rBMSCs are continuously transfected to produce therapeutic BMP-2 protein.…”

“…This is mainly due to the strong chelation effect of PDA on calcium ions, which can enrich calcium ions on the surface of the material and induce the formation of hydroxyapatite crystals. For instance, Liu reported that the hemispherical apatite particles adhered to the PDA‐coated PPBES surface, while pure PPBES group did not facilitate apatite formation 25 . On this basis, the NPEEK‐PDA‐(PLGA‐NH 2 @pBMP‐2) group had more positive ALP activity or calcium deposition.…”

“…16,17 DA undergoes oxidative self-polymerization in an alkaline medium to form a highly adhesive polydopamine(PDA) layer on the substrate, 18,19 not only endowing the substrate with a hydrophilic surface, 20 but also providing a secondary reaction platform to immobilize growth factors since its abundant catechol and amine groups react with amine-and thiol-containing substances via Michael addition or Schiff base reaction. [21][22][23][24] In addition, PDA accelerates the deposition of calcium ions from the culture solution onto the surface of a substrate, 25,26 promoting the differentiation of osteoblasts and the formation of a bone matrix. Therefore, whether for theoretical analysis or existing practical application, PDA is undoubtedly an effective method for constructing biofunctional surfaces.…”

Intrinsic osteoinductivity of PCL‐DA/PLLA semi‐IPN shape memory polymer scaffolds

“…For instance, Yao et al 46 investigated how modification of hydrophobic PCL substrates with the relatively hydrophilic PLA may enhance osteogenic differentiation of h‐MSCs. Furthermore, PD–known for improving material hydrophilicity 47 –was reported by Xu et al 48 and Deng et al 49 to enhance osteogenic differentiation of MSCs coupled with changes in substrate chemistry on HAp/polyamide 66 and electrospun PCL substrates, respectively. The reported enhancement in osteogenic differentiation due to alterations in scaffolds hydrophobicity may be a result of improved protein adsorption and cell adhesion to the scaffolds 50‐53 – both known to influence MSC osteogenic differentiation.…”