Application of Localized Surface Plasmon Resonance Spectroscopy to Investigate a Nano–Bio Interface

Abstract

The accurate determination of events at the interface between a biological system and nanomaterials is necessary for efficacy and safety evaluation of novel nano-enabled medical products. Investigating the interaction of proteins with nanoparticles (NPs) and the formation of protein corona on nanosurfaces is particularly challenging from the methodological point of view due to the multiparametric complexity of such interactions. This study demonstrated the application of localized surface plasmon resonance (LSPR) spectroscopy as a low-cost and rapid biosensing technique that can be used in parallel with other sophisticated methods to monitor nano–bio interplay. Interaction of citrate-coated gold NPs (AuNPs) with human plasma proteins was selected as a case study to evaluate the applicability and value of scientific data acquired by LSPR as compared to fluorescence spectroscopy, which is one of the most used techniques to study NP interaction with biomolecules. LSPR results obtained for interaction of AuNPs with bovine serum albumin, glycosylated human transferrin, and non-glycosylated recombinant human transferrin correlated nicely with the adsorption constants obtained by fluorescence spectroscopy. This ability, complemented by its fast operation and reliability, makes the LSPR methodology an attractive option for the investigation of a nano–bio interface.

Localized Surface Plasmon Resonance as a Tool to Study Protein Corona Formation on Nanoparticles

“…101 The analysis of Stern−Volmer plots for the interaction of glycosylated human transferrin and nonglycosylated recombinant human transferrin with Au NPs also confirmed that these proteins form stable complexes with NPs and the fluorescence is quenched following the static mechanism. 102 Barbero et al investigated the interaction of mucins of two types with Au NPs of three sizes and different capping ligands (cysteamine or thioglycolic acid). 103 They found that the affinity of proteins to NPs is affected to a greater extent by the capping agent rather than the size.…”

The effect of layer thickness and immobilization chemistry on the detection of CRP in LSPR assays

“…Proteins, for example, are known to bind directly on bare gold surfaces. However, this can have an impact on their stability and functionality 30 and can result in weakened target binding. Different immobilization methods have been developed in the past to address this challenge, as described above.…”

“…All microfluidic assays used a custom build LSPR instrument (figure S3 ) at IPHT-Leibniz. It consists of a halogen light source HL-2000-FHSA (Ocean Optics, USA), an optical fiber connected UV/VIS linear photodiode array spectrometer USB 2000+ (Ocean Optics, USA), a peristaltic pump (Ismatec Reglo-ICC, Cole-Parmer GmbH, Wertheim, Germany), a 2-way valve (Bio-Chem Fluidics Inc, Boonton, USA) for the waste and a custom designed 3D printed microfluidic chamber (figure S4 ) and sealing with two inputs and one output capillary at each channel side similar to an earlier published setup 28 – 30 . For some measurements single-use flow cells “Basic sensor platform II” (# 10001354, microfluidic chip shop GmbH, Jena, Germany) were used with adhesive tape gasket for Fl.…”

CRP Detection Using Gold Nanosensors – Effect of Layer Thickness and Immobilization Chemistry

“…Proteins, for example, are known to bind quite well directly on bare gold surfaces. However, this can have an impact on their stability and functionality 27 and can result in weakened target binding. Different immobilization methods have been developed in the past to address this problem, as discussed before.…”

“…For all the micro uidic assays a custom build LSPR instrument was used. It consists of a halogen light source HL − 2000 − FHSA (Ocean Optics, USA), an optical ber connected UV/VIS linear photodiode array spectrometer USB 2000+ (Ocean Optics, USA), a peristaltic pump (Is-matec Reglo-ICC, Cole-Parmer GmbH, Wertheim, Germany), a 2-way valve (Bio-Chem Fluidics Inc, Boonton, USA) for the waste and a custom designed 3D printed micro uidic chamber and sealing with two inputs and one output capillary at each channel side similar to an earlier published setup [25][26][27] . For some measurements single-use ow cells "Basic sensor platform II" (# 10001354, micro uidic chip shop GmbH, Jena, Germany) were used with adhesive tape gasket for Fl.…”