3D super-resolved imaging in live cells using sub-diffractive plasmonic localization of hybrid nanopillar arrays

Abstract

<jats:title>Abstract</jats:title><jats:p>Analysing dynamics of a single biomolecule using high-resolution imaging techniques has been had significant attentions to understand complex biological system. Among the many approaches, vertical nanopillar arrays in contact with the inside of cells have been reported as a one of useful imaging applications since an observation volume can be confined down to few-tens nanometre theoretically. However, the nanopillars experimentally are not able to obtain super-resolution imaging because their evanescent waves generate a high optical loss and a low signal-to-noise ratio. Also, conventional nanopillars have a limitation to yield 3D information because they do not concern field localization in <jats:italic>z</jats:italic>-axis. Here, we developed novel hybrid nanopillar arrays (HNPs) that consist of SiO<jats:sub>2</jats:sub> nanopillars terminated with gold nanodisks, allowing extreme light localization. The electromagnetic field profiles of HNPs are obtained through simulations and imaging resolution of cell membrane and biomolecules in living cells are tested using one-photon and 3D multiphoton fluorescence microscopy, respectively. Consequently, HNPs present approximately 25 times enhanced intensity compared to controls and obtained an axial and lateral resolution of 110 and 210 nm of the intensities of fluorophores conjugated with biomolecules transported in living cells. These structures can be a great platform to analyse complex intracellular environment.</jats:p>

Plasmonic Nanopillars—A Brief Investigation of Fabrication Techniques and Biological Applications

“…In numerous studies, the combination of dry etching methods with different masking techniques has been utilized for the production of nanoparticles, particularly in materials such as Si, SiN, SiO 2 , and sapphire substrates. To fabricate nanoparticles, various nanosized masks are created on a substrate using lithography techniques such as electron-beam lithography [43][44][45] and microsphere lithography [46][47][48][49]. Following this, dry etching using gases and reactive-ion etching (RIE) is carried out.…”

“…However, the fabricated structure's aspect ratio is limited, and the output of the process depends on the gas used during the process. Kim et al [43] reported the formation of NPs in thin quartz films. In their experiments, they used electron-beam lithography and RIE (Figure 1).…”

“…Kim et al [43] applied plasmonic enhancement to high-resolution fluorescence imaging using NPs to improve both the lateral and axial resolutions, as shown in Figure 9. To achieve plasmonic enhancement, a gold cap was deposited on silica (SiO 2 ) NPs with a height of 700 nm, a diameter of 200 nm, and a period of 1 µm, as shown in Figure 9a-c.…”

Surface Nano-Patterning for the Bottom-Up Growth of III-V Semiconductor Nanowire Ordered Arrays

“…Nanowires, moreover, support resonant optical modes which can be tailored and enhanced in order to modulate the reflectance, absorbance and transmittance properties of the arrays [ 9 , 13 , 15 , 34 , 35 ]. Nanowire arrays also provide a large surface-to-volume area, beneficial in all the applications based on surface interactions mechanisms, such as sensing [ 36 ], photodetection [ 37 ], and batteries electrodes [ 38 ], to name a few.…”

Semiconductor nanowire arrays for optical sensing: a numerical insight on the impact of array periodicity and density

“…In this framework, artificial calibrated arrangements of vertically aligned dielectric quasi one-dimensional structures, shaped as nanowires (NWs), provide ideal platforms to control photonic bandgap materials [13][14][15][16][17][18][19][20][21][22], and more in general are of considerable importance for building-blocks promising for next-generation sensing devices [23]. Indeed, arrays of vertically aligned one-dimensional NWs have demonstrated great potential in photonic applications due to their ability to tightly confine optical signals and to the possibility to easily adjust the growth parameters in order to tune the assemblies' optical properties during the growth [24].…”