Detection and Quantification of Single Engineered Nanoparticles in Complex Samples Using Template Matching in Wide-Field Surface Plasmon Microscopy

Abstract

An ultrasensitive analytical method for direct detection of single nanoparticles in complex environment is described. The method relies on the wide-field surface plasmon microscopy (SPM). The suppression of matrix effects is achieved by image analysis based on the template matching. First, characteristic SPM images of nanoparticles are collected in aqueous suspensions. Then the detection of nanoparticles in complex environment is performed using template matching. Quantification and characterization of nanoparticles size was demonstrated at subppb level (∼100 pg/mL) in such complex media as wines, fruit juices, or cosmetic formulation. Visualization of the nanoparticles is performed in real time. The method does not require any sample pretreatment. If the minimally acceptable adsorption rate is defined as one nanoparticle to the whole sensor surface per few seconds, the working range of the method is ∼10 to 10 nanoparticles per mL.

Identification of Nanoparticles via Plasmonic Scattering Interferometry

“…By integration with wide-field imaging capability,s urface plasmon resonance microscopy (SPRM) was developed and has been used to image nanosized objects,s uch as DNA molecules, [7] nanoparticles, [8] bacteria, and viruses, [9] owing to the particle-induced scattering of SPPs propagating along am etal film. Thep roperties of nanoparticles can be characterized with distinct parabolic interferometric scattering patterns.B ys electing regions of interest (ROIs) in the centers of parabolic patterns or using template matching,the intensities of the summed ROIs or the templates [10] have been used to estimate the size of particles [9] or the distance of particles from the metal film [8a] or to deduce the electrochemical reaction process. [11] However,these methods cannot provide material related information, for example,t he refractive index.…”

Optical Nanoimpacts of Dielectric and Metallic Nanoparticles on Gold Surface by Reflectance Microscopy: Adsorption or Bouncing?

“…In principle, these situations may be differentiated optically. The optical monitoring, in 3D [11][12][13][14] by holography or in 2D by SPR [7,8,55,56], of the reaction did not show such significant NP escape but rather that the NP stays close by (< 300 nm) to the electrode surface until its complete dissolution. On one hand, these experiments then suggest that if NPs are partially dissolved, allowing their desorption, they may not be evacuated in the solution, at least with the Brownian dynamics of a freely diffusing NP.…”

“…This perturbation is detected as a local perturbation of the reflected beam and is collected by a camera. Popular in biochemical studies, SPR was also combined with electrochemistry, and more recently as a microscopy to image heterogeneous electrochemical currents at microstructured electrodes or the electrochemistry of single NPs [3][4][5][6][7][8].…”

“…8 NPs/mL. This solution was injected into a microfluidic channel constructed from an Ibidi sticky-slide ® of 5 × 0.8 mm 2 section mounted atop an Au-coated Si substrate.…”

Advances in Optical Single‐Molecule Detection: En Route to Supersensitive Bioaffinity Assays

“…[124] Thegroup of Mirsky developed awide-field approach for the detection and quantification of single NPs [121] and applied it for the analysis of Au and Ag NPs in complex samples such as wine,a pple juice,a nd sunscreen (Figure 15). [125] Thel arge imaging area of the wide-field setup increased the probability of detecting single NP adsorption events at low concentrations.T he signal strength was mainly determined by the size and refractive index of the NPs,t he distance from the plasmonic substrate,a nd the performance of the optical system. Thea dsorption of as ingle NP,h owever, only led to as mall signal change.T oe nhance the sensitivity,d ifferential images of local temporal and spatial intensity changes were evaluated based on the changes between the two subsequently captured frames.T he method provided an LOD of 10 6 NPs mL À1 ( % 1.6 fm)a nd aw orking range of 10 6 -10 10 NPs mL À1 with am easurement time of 1min.…”