Plasmonic Coupling in Silver Nanoparticle Aggregates and Their Polymer Composite Films for Near-Infrared Photothermal Biofilm Eradication.

Padryk Merkl,Thomas Thersleff,Apostolos Zaganiaris,Mariam Shahata,Georgios A Sotiriou,Shuzhi Zhou,Athina Eleftheraki

doi:10.1021/acsanm.1c00668

Padryk Merkl, Thomas Thersleff + Show 5 more

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https://doi.org/10.1021/acsanm.1c00668

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Abstract

Plasmonic nanoparticles with near-IR (NIR) light absorption are highly attractive in biomedicine for minimally invasive photothermal treatments. However, these optical properties are typically exhibited by plasmonic nanostructures with complex, nonspherical geometries that may prohibit their broad commercialization and further integration into photothermal devices. Herein, we present the single-step aerosol self-assembly of plasmonic nanoaggregates that consisted of spherical silver nanoparticles with tunable extinction from visible to NIR wavelengths. This tunable extinction was achieved by the addition of SiO2 during the flame synthesis of the nanoparticles, which acted as a dielectric spacer between the spherical silver nanoparticles and was also computationally validated by simulating the extinction spectra of similar silver nanoaggregates. These plasmonic nanoaggregates were easily deposited on silicone polymeric surfaces and further encased with a top polymer layer, forming plasmonic photothermal nanocomposite films. The photothermal properties of the NIR nanocomposite films were utilized to eradicate the established biofilms of clinically relevant Escherichia coli and Staphylococcus aureus, with a relationship observed between the final surface temperature and biofilm eradication.

Highlights

Plasmonic nanomaterials exhibit striking optical properties that render them useful in highly sensitive diagnostic devices, potent medical treatments, and industrial tools.[1,2] Gold and silver are two of the most well-known plasmonic nanomaterials because they exhibit strong plasmonic properties in the visible region of the electromagnetic spectrum
Even though NIR photothermal silver nanomaterials exist, such as nanotriangles made by one-step seedless method,[14] advantages of the developed photothermal surfaces here include the utilization of the controlled plasmonic coupling of spherical silver nanoparticles active in the NIR region made by a rapid, scalable, and reproducible nanomanufacturing process,[15] which allows nanoparticle deposition on a selected substrate without any prior treatment or functionalization.[16]
This has been demonstrated by coating plasmonic nanoparticles with a thin SiO2 shell that acted as a dielectric spacer, effectively providing a limit on the minimum, interplasmonic, particle distance.[17−20] Such a hermetic SiO2 shell may prevent any potential dissolution of the core nanomaterial[21] and offers support for further surface functionalization.[22]

Summary

Introduction

Plasmonic nanomaterials exhibit striking optical properties that render them useful in highly sensitive diagnostic devices, potent medical treatments, and industrial tools.[1,2] Gold and silver are two of the most well-known plasmonic nanomaterials because they exhibit strong plasmonic properties in the visible region of the electromagnetic spectrum. Even though NIR photothermal silver nanomaterials exist, such as nanotriangles made by one-step seedless method,[14] advantages of the developed photothermal surfaces here include the utilization of the controlled plasmonic coupling of spherical silver nanoparticles active in the NIR region made by a rapid, scalable, and reproducible nanomanufacturing process,[15] which allows nanoparticle deposition on a selected substrate without any prior treatment or functionalization.[16] An alternative approach to extend the extinction of plasmonic nanostructures into the NIR region is to exploit the plasmonic interparticle coupling This can be achieved by the reciprocal interaction of neighboring, plasmonic, primary nanoparticles with small interparticle distances.[17] This has been demonstrated by coating plasmonic nanoparticles with a thin SiO2 shell that acted as a dielectric spacer, effectively providing a limit on the minimum, interplasmonic, particle distance.[17−20] Such a hermetic SiO2 shell may prevent any potential dissolution of the core nanomaterial[21] and offers support for further surface functionalization.[22] use of an inorganic, dielectric spacer inhibits any sintering and restructuring of the metallic plasmonic material that otherwise might occur due to the high temperatures achieved under laser irradiation.[18]

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