Enhanced Osteoconductivity and Osseointegration in Calcium Polyphosphate Bioceramic Scaffold via Lithium Doping for Bone Regeneration

Abstract

Calcium polyphosphate (CPP) is a novel bioceramic bone substitute, which is favored because its composition is highly similar to natural bone. According to previous studies, doping ions into CPP is an effective and convenient method for overcoming the shortcomings, such as poor osteoconductivity of CPP. Lithium (Li) is a fairly new additive to bone substitutes that brought attention due to its role in osteogenesis. The present study was conducted to assess whether doping Li into CPP could influence the microstructure, degradation, and osteoinductivity of CPP. The results found that both CPP and Li-doped CPP (LiCPP) had a single beta-CPP phase, indicating that Li did not affect the crystallized phase. SEM images revealed that both scaffolds were porous, while the surface of LiCPP was rougher and more uneven compared to CPP. Also, a better degradation property of LiCPP was observed via weight loss and ion release tests. In vitro study found that LiCPP extracts had advantages of promoting osteoblasts’ proliferation and differentiation over CPP extracts. In vivo study on rabbit’s cranial defects was also conducted. Microcomputed tomography and histological staining showed that LiCPP had better osteoconductivity than CPP. This study proved that doping Li into CPP is a feasible modification method, and LiCPP might be a suitable bioceramic for bone tissue engineering.

Li-Doped Ti Surface for the Improvement of Osteointegration

“…An ALP staining kit that provided a quick and easy method to stain ALP in stem cells was used with 5-bromo-4-chloro-3-indolyl phosphate (BCIP) as the substrate, and ALP staining is based on the ability of ALP to hydrolyze the phosphate group on BCIP to produce bluecolored intermediates, which are then oxidized by nitro blue tetrazolium (NBT) to form an insoluble dark-or purple−blue NBT formazan. 35 As shown in Figure 4A, the PEO coating with Li displayed denser and deeper ALP positive staining after 7 and 14 days of induction. The staining results for Ti and PEO groups were similar.…”

“…Alkaline phosphatase (ALP) is a byproduct of osteoblast activity, which has been considered to be an early indicator of osteogenic differentiation; thus, an elevated ALP is an indication of active bone formation. , Therefore, the ALP activity was measured at 7 and 14 days to investigate the osteogenic differentiation potential of rBMSCs that were cultured on the samples. An ALP staining kit that provided a quick and easy method to stain ALP in stem cells was used with 5-bromo-4-chloro-3-indolyl phosphate (BCIP) as the substrate, and ALP staining is based on the ability of ALP to hydrolyze the phosphate group on BCIP to produce blue-colored intermediates, which are then oxidized by nitro blue tetrazolium (NBT) to form an insoluble dark- or purple–blue NBT formazan . As shown in Figure A, the PEO coating with Li displayed denser and deeper ALP positive staining after 7 and 14 days of induction.…”

Design strategies for composite matrix and multifunctional polymeric scaffolds with enhanced bioactivity for bone tissue engineering

“…Once bioceramics and BGs have proven to be acceptable as coating materials (Predoi et al, 2019;Vranceanu et al, 2019), cements (Li et al, 2018;Williams, 2019), scaffolds (Zhao et al, 2014;Yin et al, 2018;Luo et al, 2019;Yuan et al, 2019;Zhuang et al, 2019), andnanoparticles (El-Rashidy et al, 2018;Chen et al, 2019;Morsi and Abd Elhamid, 2019;Singh et al, 2020c), the optimum synthesis process will depend on the application. Over the past decade, researchers have analyzed the literature to determine the effects of metal ions in various inorganic matrices for application in a wide variety of diseases.…”

Preparation and characterization of novel lithium magnesium phosphate bioceramic scaffolds facilitating bone generation

“…[25][26][27][28] Yuan et al discovered that Li doping was contributive to the enhanced osteoconduction and osseointegration of calcium polyphosphate bioceramic scaffolds. 29 Liu et al reported that the Li-containing bioactive glass ceramic was able to promote in vitro angiogenic activity and in vivo neovascularization. 23 Li et al demonstrated that a high dosage of Li (B50 ppm) is not detrimental but beneficial to the osteogenic performance of calcium phosphate cement.…”