Multifunctional MoS₂-PMMA bone cement with enhanced strength and antibacterial activity to overcome limitations of conventional materials in orthopedic surgery.

Abstract

<h4>Backgrounds</h4>The increasing incidence of osteoporotic vertebral compression fractures (OVCFs) necessitates the development of effective treatment strategies. Polymethylmethacrylate (PMMA) bone cement, which is widely used, lacks adequate antimicrobial properties and poses the risk of postoperative infections. Molybdenum disulfide (MoS₂) nanosheets, which are known for their antimicrobial and osteogenic potential, offer a novel approach.<h4>Methods</h4>We synthesized PMMA-MoS₂ nanocomposites by incorporating MoS₂ nanosheets into PMMA bone cement. The mechanical properties of the composites were evaluated using tensile tests. Additionally, finite element analysis was conducted to simulate the stress distribution in the spine after vertebroplasty. Osteoblast viability, differentiation, and maturation were assessed using the CCK-8 assay, alkaline phosphatase (ALP) staining, and alizarin red S (ARS) staining. The antimicrobial activity was tested against Escherichia coli.<h4>Results</h4>PMMA-MoS₂ nanocomposites significantly increased elastic modulus from 2100.1 ± 29.7 to 2706.1 ± 14.7 MPa (P < 0.05) and tensile strength from 45.2 ± 2.1 to 56.9 ± 1.5 MPa at 5% MoS₂. Finite element models showed no significant alterations in stress distribution patterns on the adjacent vertebral surfaces, indicating mechanical stability. As assessed by CCK-8 assays, the presence of MoS₂ led to a marked increase in osteoblast proliferation, with cell viability consistently exceeding 100% at all time points. ALP staining demonstrated a concentration-dependent enhancement in osteoblast differentiation, with the PMMA + 5%MoS₂ composite showing the highest ALP activity. Moreover, the ARS-stained area expanded as the MoS₂ concentration increased, indicating a pronounced increase in the formation of mineralized nodules. Antimicrobial testing confirmed that the PMMA-MoS₂ composites substantially reduced Escherichia coli counts, with the PMMA + 5%MoS₂ composite exhibiting the most potent effect.<h4>Conclusions</h4>This study demonstrates that PMMA-MoS₂ nanocomposites offer improved mechanical, osteogenic, and antimicrobial properties, presenting a promising material for orthopedic applications.