Zero-Mode Waveguide Nanophotonic Structures for Single Molecule Characterization

Area of Science:

• Chemical and life sciences
• Nanophotonics
• Optical spectroscopy

Background:

• Single-molecule characterization is vital but faces challenges like limited concentration ranges and photobleaching.
• Nanophotonics and non-classical optics offer solutions for studying challenging biomolecular interactions.
• Low-affinity interactions (K~mM) are difficult to study with traditional methods.

Purpose of the Study:

• To review nanophotonic devices for single-molecule studies.
• To highlight zero-mode waveguides (ZMWs) as key nanostructures.
• To discuss the integration of ZMWs with various analytical techniques.

Main Methods:

• Fabrication of optical nanostructures, specifically zero-mode waveguides (ZMWs) in gold or aluminum films.
• Confining observation volumes to attoliter-zeptoliter scales using ZMWs.
• Integration of ZMWs with optical probes like single molecule fluorescence, smFRET, and FCS.
• Development of multifunctional devices like electrochemical ZMWs (E-ZMWs).

Main Results:

• ZMWs enable isolation of single molecules for analysis, even at high bulk concentrations (μM-mM).
• Arrays of ZMWs facilitate parallel, distributed analysis of numerous single-molecule events.
• ZMWs can be combined with electrochemical functions for multimodal analysis.

Conclusions:

• Zero-mode waveguides are effective nanophotonic tools for overcoming limitations in single-molecule studies.
• ZMWs significantly enhance the ability to study low-affinity biomolecular interactions.
• The integration of ZMWs into chemical and biochemical analysis systems offers broad applicability.