Characterizing Single Polymeric and Protein Nanoparticles with Surface Plasmon Resonance Imaging Measurements

Abstract

Near-infrared surface plasmon resonance imaging (SPRI) microscopy is used to detect and characterize the adsorption of single polymeric and protein nanoparticles (PPNPs) onto chemically modified gold thin films in real time. The single-nanoparticle SPRI responses, Δ%RNP, from several hundred adsorbed nanoparticles are collected in a single SPRI adsorption measurement. Analysis of Δ%RNP frequency distribution histograms is used to provide information on the size, material content, and interparticle interactions of the PPNPs. Examples include the measurement of log-normal Δ%RNP distributions for mixtures of polystyrene nanoparticles, the quantitation of bioaffinity uptake into and aggregation of porous NIPAm-based (N-isopropylacrylamide) hydrogel nanoparticles specifically engineered to bind peptides and proteins, and the characterization of the negative single-nanoparticle SPRI response and log-normal Δ%RNP distributions obtained for three different types of genetically encoded gas-filled protein nanostructures derived from bacteria.

Identification of Nanoparticles via Plasmonic Scattering Interferometry

“…For nanobubbles, since their refractive index is nearly one, ψ is near π, and the center of the pattern is dark. This result was confirmed by the plasmonic imaging of gas vesicles with a 2 nm protein shell …”

“…Recently,r esearchers attempted to characterize patterns by measuring the intensity of selected particles along and across the direction of the plasmonic wave. [9,13] Although the intensity fluctuations along these lines profiled the width and shape of the pattern, the parabolic patterns were found to be almost identical for nanoparticles with different refractive indices and sizes. [13a] Therefore,t he knowledge gap between the features of parabolic patterns and the scattering properties of particles has led to al ack of methods for accurately extracting information from patterns.…”

Detection and Digital Resolution Counting of Nanoparticles with Optical Resonators and Applications in Biosensing

“…A variety of nanoscale particles, such as metallic nanoparticles [129], dielectric nanoparticles [130,131], protein nanoparticles [132,133] and single DNA molecules [134,135] have been observed with this system. In addition, orthogonal and complementary measurement techniques, such as electrochemistry [129,136,137] and local thermal measurement [138], have also be incorporated into the system.…”

“…SPR imaging microscopy is especially powerful in the field of polymeric and protein nanoparticle (PPNP) detection, where high throughput and high sensitivity real-time characterization of dielectric nanoparticles is required. Corn et al recently utilized SPR imaging microscopy to characterize the size, material content and the inter-particle interactions of PPNPs, in which changes in the intensity of average single-nanoparticle surface plasmon resonance image (SPRI) response (∆%R NP ) at the center of the diffraction pattern is used to quantify the bioaffinity uptake of polypeptides and proteins by a variety of solid, porous PPNPs [133]. Figure 5h shows the frequency distribution histogram of the SPR responses of NIPAm-based hydrogel nanoparticles (d = 272 nm) in both the absence and presence of melittin.…”

Particle sensing with confined optical field enhanced fluorescence emission (Cofefe)

“…SPRM has been successfully employed to probe individual cells [13], bacteria and viruses [14,15], DNA [16,17], and protein structures. [18] The ultimate sensitivity of SPRM is limited by various factors. [19][20][21] One limitation is related to the fact that SPR methods are not background-free, as small changes in the light intensity need to be discriminated against a bright background.…”