AUTHOR=Qiu Gengtao , Huang Mingguang , Ke Difeng , Liu Jin , Weir Michael D. , Ma Tao , Wang Ping , Oates Thomas W. , Schneider Abraham , Xia Yang , Xu Hockin H. K. , Zhao Liang 

TITLE=Novel injectable calcium phosphate scaffold with human periodontal ligament stem cell encapsulation in microbeads for bone regeneration

JOURNAL=Frontiers in Materials

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.977853

DOI=10.3389/fmats.2022.977853

ISSN=2296-8016

ABSTRACT=<p><bold>Objectives:</bold> 1) Develop a novel construct of human periodontal ligament stem cells (hPDLSCs) encapsulated in degradable alginate microbeads (DAMB) with human platelet lysate (hPL) and injectable calcium phosphate cement (ICPC); 2) Investigate the proliferation and osteogenic differentiation of hPDLSCs in ICPC with hPL as a xeno-free supplement and animal serum replacement for bone tissue engineering applications.</p><p><bold>Methods:</bold> hPDLSCs were encapsulated in alginate-fibrin microbeads (DAMB + fibrin), alginate-hPL degradable microbeads (DAMB + hPL), or alginate-fibrin-hPL microbeads (DAMB + fibrin + hPL). The proliferation and osteogenic differentiation of hPDLSCs were investigated in culturing with the ICPC scaffold.</p><p><bold>Results:</bold> Flexural strength of ICPC was 8.4 ± 0.91 MPa, and elastic modulus was 1.56 ± 0.1 GPa, exceeding those of cancellous bone. hPDLSCs had higher viability in DAMB + fibrin + hPL group than in DAMB + fibrin. ALP was 69.97 ± 16.96 mU/mg for ICPC + DAMB + fibrin + hPL group, higher than 30.68 ± 2.86 mU/mg of ICPC + DAMB + fibrin (<italic>p</italic> &lt; 0.05) and 4.12 ± 1.65 mU/mg of control (<italic>p</italic> &lt; 0.01). At 7 days, osteogenic gene expressions (<italic>ALP</italic>, <italic>RUNX2</italic>, <italic>COL1</italic>, and <italic>OPN</italic>) in ICPC + DAMB + fibrin + hPL and ICPC + DAMB + fibrin were 4–11 folds that of control. At 21 days, the hPDLSC-synthesized bone mineral amounts in ICPC + DAMB + fibrin + hPL and ICPC + DAMB + fibrin were 13.2 folds and 11.1 folds that of control group, respectively.</p><p><bold>Conclusion:</bold> The novel injectable CPC scaffold encapsulating hPDLSCs and hPL is promising to protect and deliver hPDLSCs. The hPL-based medium significantly enhanced the osteogenic differentiation of hPDLSCs in ICPC + DAMB + fibrin + hPL construct, suggesting a promising xeno-free approach for bone tissue regeneration applications.</p>