Polymers for Surface‐Functionalization and Biocompatibility of Inorganic Nanocrystals

Abstract

Hybrid nanomaterials combining inorganic nanostructures with organic molecules such as polymers and biomolecules offer flexible platforms with size‐ and composition‐tunable properties. These materials have shown promising use in an array of applications ranging from optical devices to biologically active platforms, facilitating important functions such as sensing, imaging, and as diagnostic tools. One of the key requirements to the integration of these inorganic nanostructures into biology is the ability to effectively control and tune their interfaces with the surrounding media. Block copolymers provide versatile molecules with dimensions comparable to those of the inorganic nanostructures and the ability to chemically tune their properties and behavior (solubility and such) over multiple length scales. Amphiphilic polymers have been used by several groups as ligands or/and capsules to promote the transfer of a variety of inorganic nanomaterials (Au nanoparticles, magnetic nanocrystals, and semiconducting nanocrystals) to buffer media and to render them biocompatible. In this article, we provide an overview of the recent developments using various amphiphilic polymers to interface inorganic nanocrystals with biological media. We start with a brief description of the most common routes for growing a few representative high quality nanocrystals of semiconductors (ie, quantum dots), metal, and metal oxide materials. We then discuss the strategies to solubilize those nanocrystals in buffer media using amphiphilic polymers and provide a few representative examples where these hydrophilic platforms have been used as sensors and imaging probes.

Small, Clickable, and Monovalent Magnetofluorescent Nanoparticles Enable Mechanogenetic Regulation of Receptors in a Crowded Live-Cell Microenvironment

“…The previously developed MPNs integrate all three components, where Zn 0.4 Fe 2.6 O 4 magnetic core (13 nm) coated with a thin (2 nm) SiO 2 layer (M@SiO 2 ), a plasmonic Au shell (thickness: > 10 nm), and an oligonucleotide tether serve as the force-generating, imaging, and targeting domains, respectively 29 . The gold shell additionally facilitates 1) formation of a robust, dense, and thin polyethylene glycol (PEG) surface passivation layer providing excellent colloidal nanoparticle stability 35,36 , 2) modular conjugation with the targeting domain via well-established Au-S chemistry 37 , and thereby 3) isolation of monovalent MPNs under harsh purification conditions. Since the gold shell comprises a significant portion of MPNs, its replacement with a smaller component while keeping other components can significantly reduce the total probe size.…”