Phospholipid-Dextran with a Single Coupling Point: a Useful Amphiphile for Functionalization of Nanomaterials

TL;DR

This paper introduces a novel dextran-phospholipid conjugate that effectively stabilizes various nanomaterials, enhancing their biocompatibility and optical properties for biological applications.

Contribution

The synthesis and application of singly-substituted dextran-phospholipid conjugates as stable, biocompatible coatings for nanomaterials is a new approach demonstrated in this study.

Findings

Stable suspensions of carbon nanotubes, gold nanoparticles, and gold nanorods were achieved.

Dextran-DSPE provided brighter photoluminescence for carbon nanotubes.

The conjugate showed superior stability and yield compared to existing surfactants.

Abstract

Nanomaterials hold much promise for biological applications, but they require appropriate functionalization to provide biocompatibility in biological environments. For non-covalent functionalization with biocompatible polymers, the polymer must also remain attached to the nanomaterial after removal of its excess to mimic the high dilution conditions of administration in vivo. Reported here are the synthesis and utilization singly-substituted conjugates of dextran and a phospholipid (Dextran-DSPE) as stable coatings for nanomaterials. Suspensions of single walled carbon nanotubes were found not only to be stable to phosphate buffered saline (PBS), serum, and a variety of pHs after excess polymer removal, but also provide brighter photoluminescence than carbon nanotubes suspended by poly(ethylene glycol)-DSPE. In addition, both gold nanoparticles (AuNPs) and gold nanorods (AuNRs) were found to maintain their dispersion and characteristic optical absorbance after transfer into Dextran-DSPE, and were obtained in much better yield than similar suspensions with PEG-phospholipid and commonly used thiol-PEG. These suspensions were also stable to PBS, serum, and a variety of pHs after removal of excess polymer. Dextran-DSPE thus shows great promise as a general surfactant material for the functionalization of a variety of nanomaterials, which could facilitate future biological applications.