In Vivo Assessment of Synthetic and Biological-Derived Calcium Phosphate-Based Coatings Fabricated by Pulsed Laser Deposition: A Review

Abstract

The aim of this review is to present the state-of-the art achievements reported in the last two decades in the field of pulsed laser deposition (PLD) of biocompatible calcium phosphate (CaP)-based coatings for medical implants, with an emphasis on their in vivo biological performances. There are studies in the dedicated literature on the in vivo testing of CaP-based coatings (especially hydroxyapatite, HA) synthesized by many physical vapor deposition methods, but only a few of them addressed the PLD technique. Therefore, a brief description of the PLD technique, along with some information on the currently used substrates for the synthesis of CaP-based structures, and a short presentation of the advantages of using various animal and human implant models will be provided. For an in-depth in vivo assessment of both synthetic and biological-derived CaP-based PLD coatings, a special attention will be dedicated to the results obtained by standardized and micro-radiographies, (micro) computed tomography and histomorphometry, tomodensitometry, histology, scanning and transmission electron microscopies, and mechanical testing. One main specific result of the in vivo analyzed studies is related to the demonstrated superior osseointegration characteristics of the metallic (generally Ti) implants functionalized with CaP-based coatings when compared to simple (control) Ti ones, which are considered as the “gold standard” for implantological applications. Thus, all such important in vivo outcomes were gathered, compiled and thoroughly discussed both to clearly understand the current status of this research domain, and to be able to advance perspectives of these synthetic and biological-derived CaP coatings for future clinical applications.

Probing the Structure, Cytocompatibility, and Antimicrobial Efficacy of Silver-, Strontium-, and Zinc-Doped Monetite

“…Among the most interesting materials in terms of their biocompatibility and similarity to hard tissue are metal phosphates, especially calcium phosphate compounds (CPCs), 10 − 12 which can be applied as either bone cement 13 , 14 or coating layers for bioinert implants. 15 − 21 For instance, crystalline hydroxyapatite (HA) with the formula Ca 10 (PO 4 ) 6 (OH) 2 is the closest CPC to the biological apatite with the formula Ca 5 (PO 4 ) 2.5 (CO 3 ) 0.5 (OH), which could vary in size, perfection, and concentration of minor components (e.g., carbonate and magnesium) and constitutes the mineral phases of teeth and bones. 22 − 24 In addition, some other forms of doped apatite, such as fluor-carbonate hydroxyapatite, are found in fish enameloids.…”

Review of Various Hydroxyapatite Coating Methods on SS316L Foam for Biomedical Application

“…As shown schematically in Fig. 4 (a), (b), the working principle of PLD is straightforward which utilising pulses of laser energy to form a thin layer of coating [122,123]. Then, the vaporised coating materials containing neutrals, ions, electrons and other elements will expand rapidly away from the target surface at velocity typically ~106 cms -1 .…”

Bioactive Coatings Loaded with Osteogenic Protein for Metallic Implants

“…Surface modification of metallic implants, either performed by mechanical, chemical, or physical techniques [14][15][16], results in beneficial outcomes in implants' reactivity, hy-2 of 19 drophilicity, roughness, surface energy and charge, and, especially, biocompatibility. The physical methods that have been applied to enhance the osteogenic activity of implantable metallic biomaterials include thermal spraying [17], sputtering [18], ion implantation [19], plasma treatment [20], and laser-assisted processing [21]. Special attention was oriented towards the latter category, given the enhanced physicochemical properties and boosted biofunctional performance of laser-textured [22][23][24] and coated [25,26] metallic implants.…”

“…Synthetic HAp is responsible for an increased concentration of local Ca 2+ , which can further stimulate osteoblasts proliferation and encourage the growth and differentiation of mesenchymal stem cells [36]. HAp-based laser-processed coatings demonstrated high efficiency for osseointegration of metallic implants and subsequent bone regeneration [21,34].…”