Phase-Tunable Calcium Phosphate Biomaterials Synthesis and Application in Protein Delivery

Abstract

Calcium phosphates (CaP) are important biomaterials used in tissue engineering and drug delivery, due to their biocompatibility, low toxicity, and osteoconductivity. However, controlling the phase of CaP, especially tricalcium phosphate (TCP), is very challenging under mild conditions, particularly when using one preparation protocol for all CaP phases. It is also crucial to produce these biomaterials economically and reproducibly. Herein, three of the most commonly employed CaP, including beta-tricalcium phosphate (β-TCP), dicalcium phosphate anhydrous (DCPA), and hydroxyapatite (HA) were, for the first time, successfully synthesised by altering the reaction solvent, using calcium acetate monohydrate as a precursor and a rapid microwave-assisted synthetic method. A variety of CaP particle morphologies were obtained, including elliptical and plate-shaped with different porosities. Compared with conventional heating, CaP biomaterials synthesised using microwave heating showed greater reproducibility, higher yields, and shorter reaction time. By varying the reaction solvents, morphologies and phases of CaP were controlled, leading to an enhanced protein bovine serum albumin (BSA) loading, with a higher BSA absorption observed according to the trend DCPA> β-TCP > HA. Furthermore, the phase, specific surface area and pores size were shown to play decisive roles in protein desorption with a higher release amount observed according to the trend DCPA > β-TCP

Highly Porous Amorphous Calcium Phosphate for Drug Delivery and Bio-Medical Applications

“…ACP precipitated from aqueous solution also appears to have a short lifetime [25,27]. In order to avoid hydrolysis, synthetic methods in organic solvents [28], including solvothermal synthesis [7,29], have become popular in recent years. Organic solvents, i.e., alcohols, favor the formation of ACP because their lower dielectric constants than of water.…”

Osteogenic, Angiogenic, and Antibacterial Bioactive Nano-Hydroxyapatite Co-Synthesized Using γ-Polyglutamic Acid and Copper

“…Crystallite sizes were estimated using the Scherrer’s equation . The crystallinity ( X c ) of the apatite phase can be evaluated base on the equation: X c = ( K A /fwhm), where K A is a constant set at 0.24 and fwhm is the higher half-maximum (in degrees) of (0 0 2) reflection …”

“…Tissue-engineered bone is the most promising biomaterial used to repair bone defects and promote the growth of permanent new bone tissue. , Calcium phosphates (CaPs) have attracted significant attention within the research community because of their biocompatibility, osteoconductivity, degradability, and role as a necessary structural component of bone. − However, the lack of osteoinductivity of CaPs limits their applicability with respect to clinical usefulness . Many works have shown that growth factors (GFs) such as bone morphogenic protein 2 (BMP-2) can be incorporated into CaPs to enhance osteoinduction.…”

Flame-Made Calcium Phosphate Nanoparticles with High Drug Loading for Delivery of Biologics

“…In order to establish the experimental protocol for loading biologics on CaP nanoparticles, bovine serum albumin (BSA, ≥96%, Sigma-Aldrich, Stockholm, Sweden, MW: 66430.3 g/mol) and bradykinin acetate salt (≥98%, Sigma-Aldrich, Stockholm, Sweden, MW: 1060.2 g/mol) were selected as model protein and peptide, respectively. BSA was selected as model protein because of its stability and its wide application in evaluating sustained drug release systems [55,56], whereas bradykinin is rather small and can act as model for the loading of larger ones. Further on, as a case study LL-37 antimicrobial peptide (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES, >95%, Innovagen, Lund, Sweden, MW: 4493.3 g/mol) was loaded on CaP nanoparticles and the antibacterial efficiency of the LL-37-CaP nanoconjugates was evaluated.…”