Modulating protein adsorption onto hydroxyapatite particles using different amino acid treatments

Abstract

Hydroxyapatite (HA) is a material of choice for bone grafts owing to its chemical and structural similarities to the mineral phase of hard tissues. The combination of osteogenic proteins with HA materials that carry and deliver the proteins to the bone-defective areas will accelerate bone regeneration. The study investigated the treatment of HA particles with different amino acids such as serine (Ser), asparagine (Asn), aspartic acid (Asp) and arginine (Arg) to enhance the adsorption ability of HA carrier for delivering therapeutic proteins to the body. The crystallinity of HA reduced when amino acids were added during HA preparation. Depending on the types of amino acid, the specific surface area of the amino acid-functionalized HA particles varied from 105 to 149 m 2 g -1. Bovine serum albumin (BSA) and lysozyme were used as model proteins for adsorption study. The protein adsorption onto the surface of amino acid-functionalized HA depended on the polarities of HA particles, whereby, compared with lysozyme, BSA demonstrated higher affinity towards positively charged Arg-HA. Alternatively, the binding affinity of lysozyme onto the negatively charged Asp-HA was higher when compared with BSA. The BSA and lysozyme adsorptions onto the amino acid-functionalized HA fitted better into the Freundlich than Langmuir model. The amino acid-functionalized HA particles that had higher protein adsorption demonstrated a lower protein-release rate.

Environmental pH-controlled loading and release of protein on mesoporous hydroxyapatite nanoparticles for bone tissue engineering

“…To our knowledge, attention has been focused on the amount of adsorption for large biomolecules, while models of adsorption onto MHA have scarcely been mentioned in the previous papers. Wassell et al found that biomolecule adsorption behavior on traditional hydroxyapatite particles fitted with the Langmuir model [23], and Lee et al drew a conclusion that bovine serum albumin (BSA) and lysozyme adsorption onto amino acidfunctionalized hydroxyapatite particles fitted better into the Freundlich model than the Langmuir model [22]. However, whether biomolecule adsorption on MHA exhibits similar behavior has not been reported.…”

“…The adsorption behaviors of large biomolecules onto hydroxyapatite have been frequently studied [16,17,19,22]. To our knowledge, attention has been focused on the amount of adsorption for large biomolecules, while models of adsorption onto MHA have scarcely been mentioned in the previous papers.…”

Electrochemical Quartz Crystal Microbalance and X-Ray Photoelectron Spectroscopy study of cathodic reactions in Bovine Serum Albumin containing solutions on a Physical Vapour Deposition-CoCrMo biomedical alloy

“…The electrical charge of the adsorbing surface can also affect adsorption as it determines electrostatic forces between proteins and surface. Such forces were for example found to govern adsorption of BSA onto functionalized hydroxyapatite particles [12]. Therefore the electrochemical conditions are supposed to influence protein adsorption.…”

Biodegradable and Biocompatible Systems Based on Hydroxyapatite Nanoparticles

“…Acidic amino acids (e.g., aspartic or glutamic acids) lead to a negatively charged surface that is ideal for the selective uptake of positive charged LSM. By contrast, basic amino acids (e.g., arginine) enhance the adsorption of negative charged proteins such as bovine serum albumin [142]. In the same way, organic compounds like mercaptosuccinic acid and citric acid were employed to increase the uptake of cytochrome C [143] and LSM [144], respectively.…”