Optical control of gradient sedimentation fractionation of anisotropic plasmon resonance nanoparticles
Daniil A. Puzanov 1, Vladimir A. Bogatyrev 1,2
1. Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (IBPPM RAS), Saratov, Russia
2. Saratov State University, Saratov, Russia;
Abstract
Currently, gold nanoparticles (AuNPs), which are attractive objects for use as drug delivery transport, are usually stabilized by CTAB, which has noticeable cytotoxicity, limiting the use of such AuNPs in medicine. Therefore, an important task to improve the bioavailability of AuNPs is their coating with an additional layer of biocompatible polymer, which neutralizes cytotoxicity. We chose chitosan for this purpose.
Until now, Au@Hit was obtained by a one-step synthesis method, using chitosan as a reducer of chloroorotic acid and as a stabilizing agent for nanoparticles. The resulting nanoparticles exhibit significant polydispersity in size and shape. Attempts to stabilize citrate AuNPs with chitosan are associated with material coagulation, accompanied by nanoparticle recharging. To prevent this undesirable phenomenon, it is possible to create conditions that limit Brownian motion of the nanoparticles, which is easily achieved by increasing the viscosity of the dispersion medium.
Previously, we used centrifugation in a glycerol concentration gradient to separate a mixture of plasmon-resonant particles (PRP) – gold nanospheres and rods. In this work, we propose using a nonlinear density gradient with an inverse viscosity gradient for fractionating gold bipyramids (AuBPs) and removing unwanted products. This approach eliminates the preliminary concentration step, significantly reducing the risk of quality loss due to coagulation.
The obtaining of AuBPs@Hit fractions of different sizes was confirmed by UV-Vis spectroscopy based on the positions of the surface plasmon resonance (SPR) peaks. Surface modification of AuBPs stabilized by CTAB was confirmed by a red shift of the SPR peaks, observed as a result of dielectric chitosan shell coating.
Speaker
Daniil Puzanov
Graduate student of Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences (IBPPM RAS)
Russia
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