Nanopore-Induced Spontaneous Concentration for Optofluidic Sensing and Particle Assembly

Abstract

Metallic nanopore arrays have emerged as optofluidic platforms with multifarious sensing and analytical capabilities such as label-free surface plasmon resonance (SPR) sensing of molecular binding interactions and surface-enhanced Raman spectroscopy (SERS). However, directed delivery of analytes through open nanopores using traditional methods such as external electric fields or pressure gradients still remains difficult. We demonstrate that nanopore arrays have an intrinsic ability to promote flow through them via capillary flow and evaporation. This passive “nano-drain” mechanism is utilized to concentrate biomolecules on the surface of nanopores for improved detection sensitivity or create ordered nanoscale arrays of beads and liposomes. Without using any external pump or fluidic interconnects, we can concentrate and detect the presence of less than a femtomole of streptavidin in 10 µL of sample using fluorescence imaging. Liposome nanoarrays are also prepared in less than 5 minutes and used to detect lipid-protein interactions. We also demonstrate label-free SPR detection of analytes using metallic nanopore arrays. This method provides a fast, simple, transportable and small-volume platform for labeled as well as label-free plasmonic analysis while improving the detection time and sensitivity.

Plasmonic Nanohole Sensor for Capturing Single Virus‐Like Particles toward Virucidal Drug Evaluation

“…So far, biosensing applications for periodic nanohole arrays have strictly focused on binding detection, and other biosensing possibilities such as analysis of conformational changes and structural transformations remain to be explored. Taking into account the high sensitivity of the periodic nanohole array along with versatile sensing possibilities (e.g., flow‐through configuration, high‐throughput measurements, and compatibility with other surface‐sensitive measurement techniques), there is compelling motivation to explore new applications for periodic nanohole arrays, especially in the context of virucidal drug evaluation.…”

Through a Window, Brightly: A Review of Selected Nanofabricated Thin-Film Platforms for Spectroscopy, Imaging, and Detection

“…Fluorescence is the most likely optical technique to be used in conjunction with a nanopore, but one could imagine that a suitably structured gold film, separated by a well-defined nanopore gap containing an analyte, might also be used for surface-enhanced Raman spectroscopy. 20,27,46,61,90,[267][268][269][305][306][307][308][309][310][311][312][313][314][315] Extensions to Nanopore Arrays. We conclude our discussion of the merging of physical-and optical-based nanopore sensing and manipulation approaches, with the consideration of nanopore arrays.…”

Capturing molecules with plasmonic nanotips in microfluidic channels by dielectrophoresis

“…For example, suspensions of analyte and gold nanoparticles have been introduced into a microfluidic channel with a decreasing diameter for the sensing of β-amyloid. 11 Nanoelectrodes in many different configurations have been used for the accumulation of particles and molecules. 10 For a liquid with test molecules flowing through nanoholes in a gold layer, a shift of the plasmon resonance has been observed, depending on the molecule concentration of the analyte.…”