There Are over 60 Ways to Produce Biocompatible Calcium Orthophosphate (CaPO4) Deposits on Various Substrates

Abstract

A The present overview describes various production techniques for biocompatible calcium orthophosphate (abbreviated as CaPO4) deposits (coatings, films and layers) on the surfaces of various types of substrates to impart the biocompatible properties for artificial bone grafts. Since, after being implanted, the grafts always interact with the surrounding biological tissues at the interfaces, their surface properties are considered critical to clinical success. Due to the limited number of materials that can be tolerated in vivo, a new specialty of surface engineering has been developed to desirably modify any unacceptable material surface characteristics while maintaining the useful bulk performance. In 1975, the development of this approach led to the emergence of a special class of artificial bone grafts, in which various mechanically stable (and thus suitable for load-bearing applications) implantable biomaterials and artificial devices were coated with CaPO4. Since then, more than 7500 papers have been published on this subject and more than 500 new publications are added annually. In this review, a comprehensive analysis of the available literature has been performed with the main goal of finding as many deposition techniques as possible and more than 60 methods (double that if all known modifications are counted) for producing CaPO4 deposits on various substrates have been systematically described. Thus, besides the introduction, general knowledge and terminology, this review consists of two unequal parts. The first (bigger) part is a comprehensive summary of the known CaPO4 deposition techniques both currently used and discontinued/underdeveloped ones with brief descriptions of their major physical and chemical principles coupled with the key process parameters (when possible) to inform readers of their existence and remind them of the unused ones. The second (smaller) part includes fleeting essays on the most important properties and current biomedical applications of the CaPO4 deposits with an indication of possible future developments.

Electrophoretic Deposition of Calcium Phosphates on Carbon–Carbon Composite Implants: Morphology, Phase/Chemical Composition and Biological Reactions

“…Only hexagonal HAp and amorphous phosphates were found. The detected compounds are absolutely typical of bioactive ceramics [ 19 , 20 ]. The electrophoresis deposition procedure did not lead to a formation of any cytotoxic components (as in the case of plasma spray [ 40 ], which thermally decompose raw HAp into CaO, amorphous Ca-P, tetracalcium phosphate, etc.…”

“…Surface characterization and a number of in vitro tests with the MG-63 cell culture proved the enhanced water wettability, accelerated cell proliferation, their spreading and adhesion. As a composite matrix [ 18 ], non-organic calcium phosphate minerals (such as hydroxyapatite HAp or other bioceramics [ 19 , 20 ]) are a prospective for enhancing biomechanical properties due to their ability to improve the bond strength and eliminate high stresses. Moreover, deposition of crystalline Ca-P coatings can enhance an X-ray radiopacity of amorphous carbon-based grafts that can facilitate surgical procedures during treatment.…”

Calcium Orthophosphate (CaPO4) Containing Composites for Biomedical Applications: Formulations, Properties, and Applications

“…In line with previous research, we also explore the following: "for the purpose of this review, composites are defined as those having a distinct phase distributed through their bulk, as opposed to modular or coated components" ( [40], p. 1329). Therefore, with a few exceptions, we did not consider CaPO 4 deposits produced on different materials by various deposition techniques [41][42][43][44][45][46] or CaPO 4 coated with other compounds [47][48][49][50][51]. However, we did include composite coatings.…”

Effect of Nanohydroxyapatite on Silk Fibroin–Chitosan Interactions—Molecular Dynamics Study

“…For instance, they could serve as durable, natural fillings and dental implant scaffolds. Notably, all the named substances-chitosan, fibroin, and hydroxyapatite-are either applied or considered as promising materials in dentistry thanks to their biocompatibility and mechanical properties [71][72][73][74][75]. Their degradation products are non-toxic, and the materials can be engineered to resist wear and tear depending on the number of intermolecular contacts stabilizing the molecular assemblies.…”