Penn State: NanoTethers Speed Biosensors
Penn State University has developed a new way to attach small molecules to surfaces. The work could speed assembly of nanoscale biosensors.
Penn State’s ‘tether molecules’ look to understand associations between neurotransmitters and their binding partners.
How it Works
In the brain, dozens of different small signaling molecules interact with thousands of large receptive proteins as part of the fundamental communication process between nerve cells. The brain’s cacophony of specific interactions is highly dependent on nanoscale molecular structure.
To replicate this natural process, a Penn State team was brought together headed by Anne Milasincic Andrews, associate professor of veterinary and biomedical sciences, and Paul S. Weiss, distinguished professor of chemistry and physics.
- Researchers started with a self-assembled monolayer (SAM), a single-molecule-thick layer that organizes itself on a surface. Molecules that make up the SAM terminate in and expose oligoethyleneglycol units (known to prevent adhesion of proteins and other large biomolecules).
- Next, so-called ‘tether molecules’ are inserted into the defects that naturally occur in the SAM.
- Finally, a small molecule, in this case the neurotransmitter serotonin, is chemically linked to the ‘tether molecules.’
When the surface is exposed to a solution containing many different proteins, only those with high affinities for the tethered small molecule selectively attach to the surface. The bound protein molecules can then be identified in place or removed for characterization.
Prof Andrews makes a fun comparison: "The tethered neurotransmitter acts like a fishing pole," Andrews said. As a result of inherent selectivity, it is possible to identify biomolecules, by function, from a sea of thousands of different types of molecules, she added. Weiss’ also stated his perspective on the work: "The key to obtaining a highly specific association is producing optimal spacing of the tethered neurotransmitters. The ideal spacing allows large molecules to recognize the functional groups of the small molecule while avoiding nonspecific binding to the surface itself."
Both believe because of the selectivity of these materials at the nanoscale, they are suitable for a variety of investigations in biological systems.
The research is scheduled to appear in the journal Advanced Materials (January 2008).