SILVER NANOPARTICLES AS ANTIBACTERIAL AGENTS IN BONE TISSUE INFECTIONS

Adela González Jiménez Pharmacy UCM

INTRODUCTION

Literature review of books and scientific articles was collected in databases as PubMed, Google Scholar, Scopus and WOS (Web Of Science). Keywords: biomaterials, bone infections, metallic silver nanoparticles, antibacterial properties.

BIBLIOGRAPHY 1. Chaloupka K, Malam Y, Seifalian AM. Nanosilver as a new generation of nanoproduct in biomedical applications. Trends Biotechnol. 2010;28(11):580–8. 2. Chernousova S, Epple M. Silver as antibacterial agent: Ion, nanoparticle, and metal. Angew Chemie - Int Ed. 2013;52(6):1636–53. 3. Lansdown ABG. Silver in health care: Antimicrobial effects and safety in use. Curr Probl Dermatol. 2006;33:17–34.

The use of AgNPs is a good method to prevent possible infections. Inclusion of AgNPs in bone implants can avoid a second surgical intervention. They have very low toxicity and bacteria´s resistance to them is small. The pharmacist, as a specialist in the medicine, can contribute to the inclusion of silver as an antibacterial agent and collaborate in the choice of the dual antibiotic + AgNPs system in a 3rd generation ceramic present in the implant, in order to obtain a synergistic bactericidal effect (antibiotic + AgNPs) together with the bone regeneration effect of the bioceramic.

Review of different methods to obtain AgNPs and description of

their possible mechanisms of action as an antibacterial agent. Report of the possible toxicity of the AgNPs in the human being and

bacteria resistance to the action of the AgNPs. Evaluation of AgNPs application in bone implants to prevent

infections.

OBJECTIVES MATERIAL & METHODS

RESULTS & DISCUSSION

Biofilm formation

Bone tissue engineering is an area of increasing interest because its main applications are directly related to the rising life expectancy of the population, so innovative strategies are needed for bone tissue regeneration therapies. Post-operative implant infections are one of the most serious complications associated with surgical treatments of bone diseases. Bacteria typically secrete polymeric materials after their association to form protective coatings known as biofilms, which further impedes the activity of the host defenses and/or antibiotic therapy, requiring surgical intervention to remove the implant as the only effective option. Silver is an antibacterial agent that could be used as a preventive measure to avoid the formation of a biofilm in implants by incorporation of methallic silver nanoparticles (AgNPs) into the biomaterial matrices.

Current applications of the different silver species in the human body

ACKNOWLEDGMENTS

CONCLUSIONS

AgNPs Antibacterial Activity Mechanisms

Antibacterial activity: It is directly related to the release of Ag+ ions (aqueous solution and acidic conditions).

Optimal conditions

Bone infections: We can modulate this release in the implant and regulate the antibacterial activity

Staphylococcus aureus

Escherichia coli

MBG-0.3Ag MBG-0.7AgMBG-0Ag MBG-1AgControl

MBG-0.3Ag MBG-0.7AgMBG-0Ag MBG-1AgControl

Silver ions antibacterial activity mechanisms

Dead bacteria Alive bacteria

Extracellular matrix AgNPs Biofilm destruction

Most used methods: Lee-Meisel method Creighton method Tollens method Use of micelles

AgNPs Synthesis

Light irradiation Biological methods Use of dendrimers

Argyria: Blue grey discolouration of the skin attributable to prolonged exposure to silver presence.

Toxicity

[toxic silver] = 10 mg/L vs [toxic AgNPs] = 100 mg/L

Solution: Combination with antibiotics

pMG101 plasmid

Periplasmatic protein Efflux pump

Resistance

I would like to thank Jesús Román for giving me the opportunity to participate in this Congress. Also, I would like to thank Dpto. Química Inorgánica y Bioinorgánica (UCM), especially my supervisor Ana García Fontecha.

Use of mono and polisacarides Organometallics compounds Use of polioxometalates(POMs)