Ultrasonication-assisted one-step self-assembly preparation of biocompatible fluorescent-magnetic nanobeads for rare cancer cell detection.

ABSTRACT

Multifunctional nanomaterials simultaneously possessing attractive properties, such as strong fluorescent intensity, excellent superparamagnetic behavior, easy modification and good biocompatibility, are always desired in a wide range of applications. In this work, we present a facile ultrasonication-assisted one-step self-assembly strategy for the fabrication of smart fluorescent-magnetic nanobeads (FMNBs) without using a matrix. Via one-step ultrasonication, organic-soluble superparamagnetic nanoparticles (MNPs) and quantum dots (QDs) were automatically encapsulated by amphiphilic (2-hydroxyl-3-dodecanoxyl) propylcarboxymethylchitosans (HDP-CMCHSs) through hydrophobic interaction to form hydrophilic FMNBs, presenting a good QD fluorescent property and a strong MNP magnetic response. The outer surface of the FMNBs was derived from natural biopolymer chitosans, enabling FMNBs with good biocompatibility and convenience for biological modification. As-prepared FMNBs can be easily modified with streptavidin, facilitating bioconjugation with biotin-labeled human epidermal growth factor (hEGF). hEGF-functionalized FMNBs are able to specifically recognize and capture rare target cells spiked in white blood cells, and the recovered cells can be further cultured for a long time. All of these excellent properties make nanobeads promising for circulating tumor cell (CTC) detection.