Chitosan-Conjugated Dendritic Ag Nanopowders for Photothermal Therapy Applications

We report the development of Ag nanodendrites where ultrafine Pd particles served as seeds for the subsequent deposition of Ag on their surfaces. By applying chitosan as both a reductant and a stabilizer, chitosan-conjugated Ag dendritic nanopowders were continuously synthesized using a serial system consisting of a spark discharge, an ultrasound-assisted polyol cell, and a collison atomizer with a heated tubular reactor. The resulting materials were then employed to kill cancerous cells photothermally. A spark discharge between Pd electrodes was employed to vaporize Pd components into a N₂ flow, and finally Pd particles were injected into an ultrasound irradiating Ag polyol cell to initiate Ag deposition on incoming Pd primary particles (∼4 nm in lateral dimension). The chitosan-conjugated Ag nanodendrites (∼240 nm in lateral dimension) were formed through collison atomization, and the nanodendrites were employed as sensitizers for photothermal cancerous cell killing under near-infrared irradiation in vitro.