AUTHOR=Chen Ning-Xin , Su Xiao-Lin , Feng Yao , Liu Qiong , Tan Li , Yuan Hui , Chen Yun , Zhao Jie , Zhao Ya-Qiong , Dusenge Marie Aimee , Hu Jing , Ye Qin , Ou-Yang Ze-Yue , Zhong Meng-Mei , Zhang Qian , Guo Yue , Feng Yun-Zhi , Peng Yong-Bo 

TITLE=Chitosan nanoparticles for sustained release of metformin and its derived synthetic biopolymer for bone regeneration

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1169496

DOI=10.3389/fbioe.2023.1169496

ISSN=2296-4185

ABSTRACT=<p><bold>Background:</bold> There are considerable socioeconomic costs associated with bone defects, making regenerative medicine an increasingly attractive option for treating them. Chitosan is a natural biopolymer; it is used in approaches for sustained slow release and osteogenesis, and metformin has osteoinductivity. Our study aimed to synthesize chitosan and human serum albumin (HSA) with a metformin nanoformulation to evaluate the therapeutic effects of this nanoformulation on bone defects <italic>in vitro</italic>.</p><p><bold>Methods:</bold> A pluripotent differentiation assay was performed <italic>in vitro</italic> on mouse bone marrow mesenchymal stem cells (BMSCs). Cell Counting Kit-8 was used to detect whether metformin was toxic to BMSCs. The osteogenesis-related gene expression of osteocalcin (OCN) and osteoprotegerin (OPG) from BMSCs was tested by real-time polymerase chain reaction (PCR). HSA, metformin hydrochloride, and chitosan mixtures were magnetically stirred to finish the assembly of metformin/HSA/chitosan nanoparticles (MHC NPs). The MHC NPs were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FT-IR). To test the expression of OCN and OPG, western blot were used. MHC NPs were evaluated <italic>in vitro</italic> for their osteoinductivity using alkaline phosphatase (ALP).</p><p><bold>Results:</bold> BMSCs successfully differentiated into osteogenic and adipogenic lineages <italic>in vitro</italic>. According to real-time PCR, a 50 µM concentration of metformin promoted osteogenesis in BMSCs most effectively by upregulating the osteogenic markers OCN and OPG. The microstructure of MHC NPs was spherical with an average nanosize of 20 ± 4.7 nm and zeta potential of −8.3 mV. A blueshift and redshift were observed in MHC NPs following exposure to wavelengths of 1,600–1,900 and 2,000–3,700 nm, respectively. The encapsulation (%) of metformin was more than 90%. The simulation study showed that MHC NPs have good stability and it could release metformin slowly <italic>in vitro</italic> at room temperature. Upon treatment with the studied MHC NPs for 3 days, ALP was significantly elevated in BMSCs. In addition, the MHC NPs-treated BMSCs upregulated the expression of OPG and OCN, as shown by real-time PCR and western blot.</p><p><bold>Conclusion:</bold> MHC NPs have a stable metformin release effect and osteogenic ability. Therefore, as a derived synthetic biopolymer, it is expected to play a role in bone tissue regeneration.</p>