Biological evaluation of the modified nano-amorphous phosphate calcium doped with citrate/poly-amino acid composite as a potential candidate for bone repair and reconstruction

Abstract

Large numbers of research works related to fabricating organic–inorganic composite materials have been carried out to mimic the natural structure of bone. In this study, a new modified n-ACP doped with citrate (n-ACP-cit)/poly (amino acids) (PAA) composite (n-ACP-cit/PAA) was synthesized by employing high bioactive n-ACP-cit and the biodegradable and biocompatible PAA copolymer. Its basic structure was characterized by X-ray diffraction spectroscopy, Fourier transformed infrared spectroscopy, and X-ray photoelectron spectroscopy. Moreover, the degradability, bioactivity, biocompatibility, and osteoconductivity of n-ACP-cit/PAA composite were evaluated in vitro and in vivo, using simulated body fluid (SBF) solution soaking test, mouse bone marrow mesenchymal stem cells proliferation and differentiation, morphological observation test, expression of genes associated with osteogenesis, and bone defect model repair test, respectively. The modified n-ACP-cit/PAA composite exhibited a much higher weight loss rate (36.01 wt.%) than that of PAA (23.99 wt.%) after immersing in SBF solution for 16 weeks and the pH values of local environment restored to neutral condition. Moreover, cells co-culturing with composites exhibited higher alkaline phosphatase activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes (Bmp-2, Colla I, OCN, OPN, and Runx-2) than that of PAA. Furthermore, the bone defect model repair test revealed that the composite could be intimately incorporated with the surrounding bone without causing any deleterious reaction and capable of guiding new bone formation. Together, these results indicated that the new modified bone repair n-ACP-cit/PAA composite material with specific characteristics may be designed for meeting diverse requirements from biomedical applications.

Enhancing osteoblast proliferation and bone regeneration by poly (amino acid)/selenium-doped hydroxyapatite

“…The existence of an amide bond in the PAA/Se-HA composites further confirmed this point. The introduction of Se-HA powder decreased the intensity of the PAA characteristic diffraction peak and reduced the crystallinity of PAA in the composite, which may affect the regularity of the PAA molecular chain [34,35]. In FT-IR results, the characteristic absorption peaks of composites shifted slightly compared with Se-HA and PAA.…”

“…The bending strength of PAA/Se-HA30 composites decreased in comparison with PAA, PAA/Se-HA10 and PAA/Se-HA20. This may be attributed to the agglomeration of Se-HA particles, which impeded the ductile flow of PAA chains [34].…”

Development of a Hybrid Biomimetic Enamel-Biocomposite Interface and a Study of Its Molecular Features Using Synchrotron Submicron ATR-FTIR Microspectroscopy and Multivariate Analysis Techniques

“…It has been shown that the required morphological features of the regenerated tissue can be recreated by choosing specific amino acids and conditions of biomaterial formation [ 24 ]. Current breakthrough studies demonstrate that the use of buffer systems when forming a hybrid biomimetic layer, including amino acids and alkalis, should contribute to the improved integration of synthetic systems with the dental hard tissue [ 25 , 26 , 27 , 28 ]. The introduction of amino acids and alkalinization under given conditions should increase the hierarchical organization of the pretreated organomineral matrix of apatite [ 8 , 29 , 30 , 31 ].…”