Noble Metals for Modern Implant Materials: MOCVD of Film Structures and Cytotoxical, Antibacterial, and Histological Studies.

Svetlana I Dorovskikh,Evgeniia S Vikulova,Elena V Chepeleva,Natalya B Morozova,Alphiya R Tsygankova,Dmitriy A Nasimov,Maria B Vasilieva,Eugene A Maksimovskii,Tamara V Basova,David S Sergeevichev

doi:10.3390/biomedicines9080851

Abstract

This work is aimed at developing the modification of the surface of medical implants with film materials based on noble metals in order to improve their biological characteristics. Gas-phase transportation methods were proposed to obtain such materials. To determine the effect of the material of the bottom layer of heterometallic structures, Ir, Pt, and PtIr coatings with a thickness of 1.4–1.5 μm were deposited by metal–organic chemical vapor deposition (MOCVD) on Ti6Al4V alloy discs. Two types of antibacterial components, namely, gold nanoparticles (AuNPs) and discontinuous Ag coatings, were deposited on the surface of these coatings. AuNPs (11–14 nm) were deposited by a pulsed MOCVD method, while Ag films (35–40 nm in thickness) were obtained by physical vapor deposition (PVD). The cytotoxic (24 h and 48 h, toward peripheral blood mononuclear cells (PBMCs)) and antibacterial (24 h) properties of monophase (Ag, Ir, Pt, and PtIr) and heterophase (Ag/Pt, Ag/Ir, Ag/PtIr, Au/Pt, Au/Ir, and Au/PtIr) film materials deposited on Ti-alloy samples were studied in vitro and compared with those of uncoated Ti-alloy samples. Studies of the cytokine production by PBMCs in response to incubation of the samples for 24 and 48 h and histological studies at 1 and 3 months after subcutaneous implantation in rats were also performed. Despite the comparable thickness of the fibrous capsule after 3 months, a faster completion of the active phase of encapsulation was observed for the coated implants compared to the Ti alloy analogs. For the Ag-containing samples, growth inhibition of S. epidermidis, S. aureus, Str. pyogenes, P. aeruginosa, and Ent. faecium was observed.

Highlights

platinum metal samples (Pt), and PtIr coatings were deposited on both sides of Ti-alloy substrates by an metal–organic chemical vapor deposition (MOCVD) method at the previously determined experimental parameters [31,37] in order to obtain metal coatings without impurities of oxide phases with a thickness of more than
Our results show that implants with noble metal coatings caused the formation of a dense fibrous capsule with a minimal level of immune response from the very beginning, which was consistent with the abovementioned data obtained for PtIr electrodes [61]
Monophase (Ag, Ir, Pt, and PtIr) and heterophase (Ag/Pt, Ag/Ir, Ag/PtIr, Au/Pt, Au/Ir, and Au/PtIr) film materials were deposited on a biomaterial (medical alloy Ti6 Al4 V (Ti-alloy)) by gas-phase transportation methods to study their biological characteristics

Summary

Introduction

The modern implant intended for use in orthopedic, reconstructive, and oncological practices is a complex structure that performs various functions in the body. The main properties that any of the implant materials should possess, first of all, reliability and safety of their use, including biocompatibility, osseointegration, and antibacterial properties [1]. Implants must be inert to living tissues, be not carcinogenic, have a sufficient margin of mechanical strength, and be resistant to the internal environment of the body [2,3,4]. Biocompatibility and prolonged antibacterial effect are of particular importance, where patients have reduced immunity and a tendency to infectious complications.

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Conclusion