Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material.

Yuri B Matos,Mattheus Torquato,Emilson R Viana,Rodrigo L Villanova,Edgar H De Souza,Marlene Soares,Rodrigo S Romanus

doi:10.3762/bjnano.12.63

Yuri B Matos, Mattheus Torquato + Show 5 more

Open Access

https://doi.org/10.3762/bjnano.12.63

Copy DOI

Abstract

Despite all recent advances in medical treatments, infectious diseases remain dangerous. This has led to intensive scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well-established solution in this area. The present work studied the nucleation of silver on halloysite substrates modified by chemical treatment with NaOH. The resulting stabilized Ag-NPs were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The nucleation was characterized by thermogravimetric analysis and differential scanning calorimetry. The antimicrobial properties of the Ag-NPs were investigated against E. coli and S. aureus. The potential of the Ag-NPs for industrial application was tested by dispersing them into low-density polyethylene. The importance of the chemical affinity between matrix and additive was tested through coating the Ag-NPs with dodecanethiol, a non-polar surfactant. The resulting composites were characterized by scanning electron microscopy and in terms of surface antimicrobial activity. The results demonstrate that the Ag-NPs synthesized in this work are indeed antimicrobial, and that it is possible to imbue a polymeric matrix with the antimicrobial properties of Ag-NPs.

Highlights

The number of people dying from bacterial infections has been significantly reduced with the emergence of antibiotics, but some bacterial diseases are still amongst the most dangerous to human life
We investigated the potential of the Ag-NPs for industrial application by dispersing them into lowdensity polyethylene (LDPE) and evaluating the chemical compatibility between matrix and additive by testing a dodecanethiol (DIO) coating to improve the dispersion of the Ag-NPs into LDPE
It is known that the initial nanotubular morphology of HNT is a consequence of internal torque in the crystalline structure of the clay [25]. This torque arises from the fact that, while the silicon and aluminol phases of HNT share apical oxygen atoms, the “natural spacing” of the oxygen atoms is different for the two crystalline phases, straining them to conform the oxygen into both structures at the same time

Summary

Introduction

The number of people dying from bacterial infections has been significantly reduced with the emergence of antibiotics, but some bacterial diseases are still amongst the most dangerous to human life. In this work we treated the HNT surface with NaOH to improve Ag-NP nucleation into the clay substrate. Antimicrobial surface activity tests were performed for LDPE samples doped with Ag/HNT-8 and Ag/HNT-8/DIO.

Results

Conclusion