RESUMO
As an alternative to eliminating cancer cells with minimal impacts on the nearby tissues, biocompatible nanoparticles based on silica-coated carbon nano-onions, with outstanding photothermal efficiency, are presented. Metal-doped carbon nano-onion@SiO2 materials are produced using flame synthesis. Metal complexes are injected in the flame to tune the carbon organization levels, which results in materials with excellent photostability and total photothermal conversion efficiency, regarding the incident light input, as higher as 48% for 785 nm laser. It was found that the metal dopant, even at a very low content, plays an interesting role in photothermal efficiency. We tested the effect of thin silica layers on the carbon nanosphere, first as a way to improve biocompatibility and provide a more reactive surface toward the modifications process to add vectorizing agents. Despite the primary goal of the silica shell, a notable increase in photothermal efficiency was observed. In vivo studies of the biological response to the materials as probed by the zebrafish model found that the as-prepared carbon nanospheres and the SiO2-coated particles are highly biocompatible. The SiO2-coated samples were found to be more suitable for photothermal application, due to the higher colloidal stability and higher photothermal efficiency.
RESUMO
Advances in nanomaterials have led to tremendous progress in different areas with the development of high performance and multifunctional platforms. However, a relevant gap remains in providing the mass-production of these nanomaterials with reproducible surfaces. Accordingly, the monitoring of such materials across their entire life cycle becomes mandatory to both industry and academy. In this paper, we use a microfluidic electronic tongue (e-tongue) as a user-friendly and cost-effective method to classify nanomaterials according to their surface chemistry. The chip relies on a new single response e-tongue with association of capacitors in parallel, which consisted of stainless steel microwires coated with SiO2, NiO2, Al2O3, and Fe2O3 thin films. Utilizing impedance spectroscopy and a multidimensional projection technique, the chip was sufficiently sensitive to distinguish silica nanoparticles and multiwalled carbon nanotubes dispersed in water in spite of the very small surface modifications induced by distinct functionalization and oxidation extents, respectively. Flow analyses were made acquiring the analytical readouts in a label-free mode. The device also allowed for multiplex monitoring in an unprecedented way to speed up the tests. Our goal is not to replace the traditional techniques of surface analysis, but rather propose the use of libraries from e-tongue data as benchmark for routine screening of modified nanomaterials in industry and academy.
