Adenosine Triphosphate-Encapsulated Liposomes with Plasmonic Nanoparticles for Surface Enhanced Raman Scattering-Based Immunoassays

Abstract

In this study, we prepared adenosine triphosphate (ATP) encapsulated liposomes, and assessed their applicability for the surface enhanced Raman scattering (SERS)-based assays with gold-silver alloy (Au@Ag)-assembled silica nanoparticles (NPs; SiO2@Au@Ag). The liposomes were prepared by the thin film hydration method from a mixture of l-α-phosphatidylcholine, cholesterol, and PE-PEG2000 in chloroform; evaporating the solvent, followed by hydration of the resulting thin film with ATP in phosphate-buffered saline (PBS). Upon lysis of the liposome, the SERS intensity of the SiO2@Au@Ag NPs increased with the logarithm of number of ATP-encapsulated liposomes after lysis in the range of 8 × 106 to 8 × 1010. The detection limit of liposome was calculated to be 1.3 × 10−17 mol. The successful application of ATP-encapsulated liposomes to SiO2@Au@Ag NPs based SERS analysis has opened a new avenue for Raman label chemical (RCL)-encapsulated liposome-enhanced SERS-based immunoassays.

Microfluidic SERS devices: brightening the future of bioanalysis

“…Alloys of Au and Ag combine the stability of gold and the enhancement activity of silver giving signals 10 to 100-fold higher than normal Raman signals. These types of alloys have been applied in SERS-based immunoassay [ 90 ], cell imaging [ 91 ], label-free chemical detection [ 92 ], and drug delivery [ 93 ].…”

“…Copyright 2016 American Chemical Society. e RR-encapsulated liposome-that upon stimulus release the RR and a SERS signal is generated when in contact with Au@Ag-assembled silica NPs [ 90 ]; Polymers: f Left: Au@pNIPAM SERRS-encoded tags. Right: SERRS tags scheme and corresponding map using different bands for each reporter.…”

“…used liposomes to enhance the response from the encapsulated RR when a positive detection from the SERS-based immunoassay was accomplished (Fig. 8 e) [ 90 ].…”