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Imaging of affinity microcontact printed proteins by using liquid crystals
Matthew L Tingey1, Sean Wilyana, Edward J Snodgrass
1Department of Chemical and Biological Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|July 28, 2004
Summary
Researchers designed surfaces for imaging proteins using liquid crystals. These surfaces enable precise protein detection and visualization through changes in liquid crystal orientation, offering high optical contrast for imaging applications.
Area of Science:
- Materials Science
- Surface Chemistry
- Biophysics
Background:
- Developing novel surfaces for protein imaging is crucial in biosensing.
- Affinity microcontact printing offers precise protein patterning.
- Thermotropic liquid crystals can respond to surface properties.
Purpose of the Study:
- To design and characterize surfaces for imaging affinity microcontact printed proteins using liquid crystals.
- To investigate the interaction between functionalized surfaces, proteins, and liquid crystals.
- To establish a method for high-contrast protein visualization.
Main Methods:
- Fabrication of gold films on silica substrates with oblique angle deposition.
- Functionalization with 2-mercaptoethylamine monolayers.
- Affinity microcontact printing of biotinylated bovine serum albumin (BSA) and anti-biotin IgG.
- Ellipsometric measurements for protein transfer confirmation.
- Optical microscopy to observe liquid crystal (LC) orientation (5CB and MBBA).
Main Results:
- Successful transfer of anti-biotin IgG to functionalized surfaces confirmed by ellipsometry.
- Specific IgG capture demonstrated through control experiments.
- Liquid crystals (5CB) exhibited distinct planar anchoring on protein-presenting regions.
- A transition from planar to homeotropic anchoring of 5CB was observed on amine-terminated regions without proteins, attributed to an electrical double layer.
- High optical contrast achieved between protein-supported and unsupported surface areas.
Conclusions:
- Amine-terminated surfaces uniformly align liquid crystals when protein-free.
- These surfaces possess sufficient surface free energy for capturing proteins from affinity stamps.
- The developed surfaces provide a robust platform for imaging microcontact printed proteins using liquid crystals.