In vitro assessment of nanosilver-functionalized PMMA bone cement on primary human mesenchymal stem cells and osteoblasts.

Linda Pauksch,Volker Alt,Katrin S Lips,Gabor Szalay,Sonja Hartmann,Gwendolen Reilly

doi:10.1371/journal.pone.0114740

Abstract

Peri-prosthetic infections caused by multidrug resistant bacteria have become a serious problem in surgery and orthopedics. The aim is to introduce biomaterials that avoid implant-related infections caused by multiresistant bacteria. The efficacy of silver nanoparticles (AgNP) against a broad spectrum of bacteria and against multiresistant pathogens has been repeatedly described. In the present study polymethylmethacrylate (PMMA) bone cement functionalized with AgNP and/or gentamicin were tested regarding their biocompatibility with bone forming cells. Therefore, influences on viability, cell number and differentiation of primary human mesenchymal stem cells (MSCs) and MSCs cultured in osteogenic differentiation media (MSC-OM) caused by the implant materials were studied. Furthermore, the growth behavior and the morphology of the cells on the testing material were observed. Finally, we examined the induction of cell stress, regarding antioxidative defense and endoplasmatic reticulum stress. We demonstrated similar cytocompatibility of PMMA loaded with AgNP compared to plain PMMA or PMMA loaded with gentamicin. There was no decrease in cell number, viability and osteogenic differentiation and no induction of cell stress for all three PMMA variants after 21 days. Addition of gentamicin to AgNP-loaded PMMA led to a slight decrease in osteogenic differentiation. Also an increase in cell stress was detectable for PMMA loaded with gentamicin and AgNP. In conclusion, supplementation of PMMA bone cement with gentamicin, AgNP, and both results in bone implants with an antibacterial potency and suitable cytocompatibility in MSCs and MSC-OM.

Highlights

Due to its low cost, excellent biocompatibility and mechanical strength polymethylmethacrylate (PMMA) bone cement is successfully used in fixation of artificial joints and as a filling material for bone cavities
To assess cell viability in mesenchymal stem cells (MSCs) and MSCs cultured in osteogenic differentiation media (MSC-OM) caused by the different PMMA bone cements, a MTT assay was conducted
On mRNA level, osteogenic differentiation of MSC-OMs was investigated by the marker ALP for which a slight but not significant increase was detected after incubation with plain PMMA, PMMA loaded with gentamicin, and PMMA loaded with AgNP

Summary

Introduction

Due to its low cost, excellent biocompatibility and mechanical strength polymethylmethacrylate (PMMA) bone cement is successfully used in fixation of artificial joints and as a filling material for bone cavities. PMMA bone cement, like other biomaterials, bears the risk of microbial colonization. The interstitial milieu surrounding an implant is known as a region of depressed immune function [12]. This milieu promotes the settlement of pathogens on the implant surface and the formation of biofilms. There have been several promising approaches of loading PMMA bone cement with antibiotics, like gentamicin or vancomycin [15,16,17]. Low-dose antibiotic loaded PMMA, with concentrations #1 g, is routinely used in the prevention of bacteria settlement during the first days [15]. When considering the prophylactic use of antibiotic loaded PMMA, the incorporated antibiotic has to cover a broad spectrum including gram-positive and gram-negative bacteria

Methods

Results

Conclusion