Module 8: Bio-nanotechnology (SOMS5800)
Biology can teach the physical world of electronics, computing, material science and engineering how to assemble complex functional devices that operate at the molecular level:
Above: Existing cellular machinery
driven by biochemicals such as ATP can serve as templates for
new nanotech devices.
Acknowledgement: Professor J.B.C. Findlay and Dr M.A.Harrison,
Biochemistry and Molecular Biology, University of Leeds.
Our present capacity to fabricate simple molecular tools, devices and machines is primitive compared with the sophistication of Nature, but we can learn. The module is aimed at physical scientists and engineers with little prior knowledge of biology or biochemistry. The essential features of living cells will be introduced and the way cells store information, recognise and respond to molecular signals, and transform different forms of energy (chemical, mechanical, electrical, light) will be explained. Examples of our early attempts to learn from Nature in the construction of nano-scale biosensor devices and motors will be covered.
Principles
- Overview: What can engineers learn from biology?
- Information: How information is stored in the cell and how it is read.
- Molecular recognition: How molecular recognition underlies cellular communication, material transfer into and within cells, and biotransformations.
- Bio-energy transduction devices: Inter-conversion of chemical, mechanical, electrical and light energy in cells.
- Synthetic molecular motors.
- Detection devices.
Tools
Lectures, practicals and demonstrations covering:
- Recognition: surface plasmon resonance.
- Single molecule detection: imaging methods.
- Designed interfaces.
- Nanoscale manipulation of bio-molecules: optical tweezers, molecular combing, atomic force microscopy.
Tethered bilayers
Bio-mimetics composed of phospholipids are ideal for the encapsulation of ion-channel peptides and proteins. Membranes are tethered between electrodes such that ion-channel activity can be measured, thus creating a bio-sensor. This is done either by creating arrays of patterned supporting molecules on gold or by micro-machining surfaces to create small holes over which the bilayer sits. Micro-machined supports for bilayers have been made with apertures of 10 mm-100 mm diameter. Bilayers have been formed upon these structures with resistances in excess of 10 GW.
Above: Using channels in tethered bi-layers as sensors, ion flow through the channels can be monitored by either ac or dc conductimetry.
Applications: biosensors for medical applications (eg drug screening), environmental monitoring (eg water and air quality), ion-channel structure-function studies (see diagram below).
Back to: Nanoscale science and technology
