Gold nanoparticle-coupled liposomes for enhanced plasmonic biosensing

Abstract

We report the fabrication of stable nanoclusters by salt-induced coupling of nanoparticles onto functionalized liposomes and their application in enhanced biosensing on a biomimetic surface. The coupling of nanoparticle-liposome structures and the subsequent debris removal were characterized by transmission electron microscopy (TEM) and absorption spectra. These nanoclusters were then tested for signal amplification with surface plasmon resonance (SPR), demonstrating advantages of an effective amplification by combining the large mass of lipid vesicles and the plasmonic properties of noble metal nanoparticles. Using 13 nm AuNPs-POPC nanoclusters, bacterial toxin detection was drastically enhanced with a markedly low nonspecific background, reaching a LOD of 0.1 ng/mL on a supported membrane interface. The nano-clusters prove to be a highly robust and reproducible signal amplification tag for optical biosensing, and also demonstrated a long shelf life, remain effective for over four weeks before showing signs of deterioration. A comparison between different types and sizes of noble metal nanoparticles with POPC liposomes was conducted and their effectiveness on amplification was assessed. The simple preparation procedure of liposome-nanoparticle nanoclusters reported here offers a promising bio-nanomaterial for sensitive biosensing and studies of vesicles-cell membrane interactions.

Keywords

• SPR
• SPR imaging
• Nanoparticles
• Liposomes
• Signal amplification