Trapping Nanoscale Objects in Solution

Stanford Reference:

04-213

Abstract

W.E. Moerner and Adam Cohen have patented the Anti-Brownian ELectrokinetic trap (ABEL trap) which can trap, measure, and manipulate sub-micron objects (e.g. single molecules) in solution at ambient temperature. The ABEL trap uses high-speed fluorescence microscopy to track the Brownian motion of a single fluorescent molecule. A feedback circuit applies carefully timed electric fields to the solution to induce an electrokinetic drift that cancels the Brownian motion. The ABEL trap is non-invasive, gentle, and can trap objects far smaller than can be trapped with laser tweezers. Applications include precise single-molecule measurements and nanomanfacturing.

News article - "Building a Better Molecule Trap", Science, Feb. 18 2005.

Figure


Figure description - Trapping region of the ABEL trap showing biomolecules in a microfluidic cell

Stage of Research

Proof-of-principle device trapped fluorescent polystyrene nanospheres with diameters down to 20 nm.

The ABEL trap was used to examine the photophysics of a single fluorescent protein, allophycocyanin (APC), the bacterial light-harvesting complex LH2, and the enzymatic behavior of single nitrite reductase enzymes. The technique allowed the observation of single molecules of solution-phase biomolecules for more than one second. The trap allows simultaneous measurement of brightness, excited state lifetime, and emission spectrum of the trapped object.

The trap has been developed extensively to trap ever smaller objects, down to the ultimate limit of one single fluorescent molecule.

The trapping algorithm and analysis have been extensively refined to allow real-time estimation of the diffusion coefficient and the electrokinetic mobility of the object, which enable binding and association events to be sensed.

Applications

• Research tool for studying single molecules
  • Nanomanipulation of objects in microfluidics
  • Identification of biological particles and nanoparticles
  • Single-molecule spectroscopy
  • Sorting of individual proteins
  • Photodynamics
  • Association and binding events
• Nanomanufacturing
• Studying bacterial photosynthetic regulation and biomaterials for solar energy harvesting

Advantages

• Traps sub-micron objects then can position the object with nanoscale resolution
• Can trap any object that can be imaged optically and that can be dissolved in non-corrosive solvent (e.g. water)
• Provides real-time information on fluorescence intensity, excited state lifetime, emission spectrusm, mobility, drag coefficient, and charge of a single nanoscale object
• Non-invasive, non-destructive
• Gentler than laser tweezers
• Scales more favorably for small objects than laser tweezers

Publications

• Cohen, Adam E., and W. E. Moerner. Method for trapping and manipulating nanoscale objects in solution." Applied Physics Letters 86.9 (2005): 093109.
• Cohen, Adam E., and William E. Moerner. "The anti-Brownian electrophoretic trap (ABEL trap): fabrication and software." Biomedical Optics 2005. International Society for Optics and Photonics, 2005.
• Goldsmith, Randall H., and W. E. Moerner. "Watching conformational-and photodynamics of single fluorescent proteins in solution." Nature Chemistry 2.3 (2010): 179-186.
• A. P. Fields, A. E. Cohen, "Electrokinetic trapping at the one nanometer limit," Proc. Natl. Acad. Sci. USA, 108, 8937-8942 (2011)
• Research Highlights: "Nanotechnology: Stop for brownian motion", Nature, Mar 10 2005.

Related Web Links

• The Moerner Lab/ABEL trap research
• Adam Cohen Lab

Innovators & Portfolio

• Adam Cohen   
• William Moerner   more technologies from William Moerner »

Patent Status

• Issued : 8,057,655 (USA)

Date Released

Licensing Contact

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