Influence of calcium ion-modified implant surfaces in protein adsorption and implant integration

Eduardo Anitua,Seda Ozturan,Mariló Gurruchaga,Félix Elortza,Cristina Martinez-Ramos,Isabel Goñi,Julio Suay,Andreia Cerqueira,Francisco Romero-Gavilán,Iñaki García-Arnáez,Mikel Azkargorta,Ricardo Tejero

doi:10.1186/s40729-021-00314-1

Abstract

BackgroundCalcium (Ca) is a well-known element in bone metabolism and blood coagulation. Here, we investigate the link between the protein adsorption pattern and the in vivo responses of surfaces modified with calcium ions (Ca-ion) as compared to standard titanium implant surfaces (control). We used LC–MS/MS to identify the proteins adhered to the surfaces after incubation with human serum and performed bilateral surgeries in the medial section of the femoral condyles of 18 New Zealand white rabbits to test osseointegration at 2 and 8 weeks post-implantation (n=9).ResultsCa-ion surfaces adsorbed 181.42 times more FA10 and 3.85 times less FA12 (p<0.001), which are factors of the common and the intrinsic coagulation pathways respectively. We also detected differences in A1AT, PLMN, FA12, KNG1, HEP2, LYSC, PIP, SAMP, VTNC, SAA4, and CFAH (p<0.01). At 2 and 8 weeks post-implantation, the mean bone implant contact (BIC) with Ca-ion surfaces was respectively 1.52 and 1.25 times higher, and the mean bone volume density (BVD) was respectively 1.35 and 1.13 times higher. Differences were statistically significant for BIC at 2 and 8 weeks and for BVD at 2 weeks (p<0.05).ConclusionsThe strong thrombogenic protein adsorption pattern at Ca-ion surfaces correlated with significantly higher levels of implant osseointegration. More effective implant surfaces combined with smaller implants enable less invasive surgeries, shorter healing times, and overall lower intervention costs, especially in cases of low quantity or quality of bone.

Highlights

Calcium (Ca) is a well-known element in bone metabolism and blood coagulation
At the calcium ions (Ca-ion) surface (c, d), the vacuum produced in the chamber of the scanning electron microscopy (SEM) dehydrates the CaCl2 layer and resembles a coating embedded within the surface roughness
The control and the Ca-ion-diluted surfaces show no significant differences in any roughness values, while the dehydrated deposit of CaCl2 inside the SEM chamber fills the pits of the roughness and produces a significant reduction in all roughness values with respect to the control or the Ca-ion diluted

Summary

Introduction

Calcium (Ca) is a well-known element in bone metabolism and blood coagulation. The first biological process that takes place upon implant placement is blood protein adsorption and the formation of a blood clot onto the biomaterial surface. Anitua et al International Journal of Implant Dentistry These processes are modulated by material’s physicochemical properties such as chemical composition, surface morphology, and charge [5]. The characteristics of the fibrin architecture of the blood clot are relevant to give shape and function to the forming implant-surface scaffold that mediates the adhesion, proliferation, and differentiation of cells [11, 12]. Caion signaling plays an important role in the osteoblast differentiation process, being crucial to stimulate osteoblast differentiation and increase osteogenesis by regulating osteocalcin, bone sialoprotein, osteopontin, ALP, and BMP-2 expression in mesenchymal stem cells [13]

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Conclusion