Silica-Gentamicin Nanohybrids: Synthesis and Antimicrobial Action.

Dina Mosselhy,Michael Gasik,Yanling Ge,Katrina Nordström,Simo-Pekka Hannula,Olli Natri

doi:10.3390/ma9030170

Abstract

Orthopedic applications commonly require the administration of systemic antibiotics. Gentamicin is one of the most commonly used aminoglycosides in the treatment and prophylaxis of infections associated with orthopedic applications, but gentamicin has a short half-life. However, silica nanoparticles (SiO2 NPs) can be used as elegant carriers for antibiotics to prolong their release. Our goal is the preparation and characterization of SiO2-gentamicin nanohybrids for their potential antimicrobial administration in orthopedic applications. In vitro gentamicin release profile from the nanohybrids (gentamicin-conjugated SiO2 NPs) prepared by the base-catalyzed precipitation exhibited fast release (21.4%) during the first 24 h and further extension with 43.9% release during the five-day experiment. Antimicrobial studies of the SiO2-gentamicin nanohybrids versus native SiO2 NPs and free gentamicin were performed against Bacillus subtilis (B. subtilis), Pseudomonas fluorescens (P. fluorescens) and Escherichia coli (E. coli). SiO2-gentamicin nanohybrids were most effective against B. subtilis. SiO2 NPs play no antimicrobial role. Parallel antimicrobial studies for the filter-sterilized gentamicin were performed to assess the effect of ultraviolet (UV)-irradiation on gentamicin. In summary, the initial fast gentamicin release fits the need for high concentration of antibiotics after orthopedic surgical interventions. Moreover, the extended release justifies the promising antimicrobial administration of the nanohybrids in bone applications.

Highlights

Orthopedic applications such as bone implants and open fractures necessitate therapeutic and prophylactic administration of antibiotics [1]
By X-ray diffraction (XRD), the native SiO2 NPs and SiO2 -gentamicin nanohybrids showed nearly the same XRD pattern of the broad peak with Bragg angle at 2θ around 24 ̋ (Supplementary Figure S1), which indicates that the SiO2 NPs used in the present study were amorphous in nature
We have demonstrated that the gentamicin of the SiO2 -gentamicin nanohybrids represents

Summary

Introduction

Orthopedic applications such as bone implants and open fractures necessitate therapeutic and prophylactic administration of antibiotics [1]. Microorganisms can attach onto the nails used for stabilization of fractured-bones and may lead to systemic antibiotic resistant biofilms [2]. The traditional systemic administration of antibiotics shows poor penetration to the infected tissues [3]. Materials implemented as carriers for antibiotics should have release kinetics that comply with the requirements to treat the infection [8] and should be biodegradable to exclude further surgical intervention to remove them [3,9]. Gram-negative bacteria are increasingly associated with the risk of infections leading to osteomyelitis, which has been more traditionally attributed to gram-positive bacteria, especially

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