Search

Nanomaterials represent a class of materials based on nanoscale structures. Nanomaterials are currently used in a wide variety of applications, including, optoelectronics, energy conversion, biology health care and medicine. Among different types of nanomaterials, gold nanoparticles have received considerable attention in disease diagnosis and therapy due to their optical and chemical properties (Liz-Marzan in Mater Today 7:26-31, ). This paper reports the main optical and photo-thermal properties of gold nanoparticles. Particularly, we show that gold nanorods embedded in cholesteric liquid crystals demonstrate to control the 'selective reflection' of a light beam. Investigation of the optical properties of the obtained material reveals an original and efficient tool to detect temperature variations at the nanoscale useful for photo-thermal based therapies applications. Finally, the concept of 'nanoparticle-protein corona interaction can be exploited for application ranging from regenerative medicine to theranostics. [ABSTRACT FROM AUTHOR]

Plasmonic metallic nanoparticles (NPs) represent a relevant class of nanomaterials, which is able to achieve light localization down to nanoscale by exploiting a phenomenon called Localized Plasmon Resonance. In the last few years, NPs have been proposed to trigger DNA release or enhance ablation of diseased tissues, while minimizing damage to healthy tissues. In view of the therapeutic relevance of such plasmonic NPs; a detailed characterization of the electrostatic interaction between positively charged gold nanorods (GNRs) and a negatively charged whole-genome DNA solution is reported. The preparation of the hybrid biosystem has been investigated as a function of DNA concentration by means of ζ-potential; hydrodynamic diameter and gel electrophoresis analysis. The results have pointed out the specific conditions to achieve the most promising GNRs/DNA complex and its photo-thermal properties have been investigated. The overall study allows to envisage the possibility to ingeniously combine plasmonic and biological materials and, thus, enable design and development of an original non invasive all-optical methodology for monitoring photo-induced temperature variation with high sensitivity. [ABSTRACT FROM AUTHOR]

Plasmonic photo-thermal therapy (PPTT) is a minimally invasive, drug-free, therapy based on the properties of noble metal nanoparticles, able to convert a bio-transparent electromagnetic radiation into heat. PPTT has been used against cancer and other diseases. Herein, we demonstrate an antimicrobial methodology based on the properties of gold nanorods (GNRs). Under a resonant laser irradiation GNRs become highly efficient light to heat nano-converters extremely useful for PPTT applications. The concept here is to assess the antimicrobial effect of easy to synthesize, suitably purified, water-dispersible GNRs on Escherichia coli bacteria. A control on the GNRs concentration used for the process has been demonstrated critical in order to rule out cytotoxic effects on the cells, and still to be able to generate, under a near infrared illumination, an adequate amount of heat suited to increase the temperature up to ≈50 °C in about 5 min. Viability experiments evidenced that the proposed system accomplished a killing efficiency suitable to reducing the Escherichia coli population of about 2 log CFU (colony-forming unit). [ABSTRACT FROM AUTHOR]