BIOTECH

NANOBIOTECHNOLOGY

Richard Feynman (1959)

  • first scientist to suggest that devices and materials would someday be fabricated to atomic specifications

Nanotechnology

  • involves the individual manipulation of single molecules or even atoms

  • building components atom by atom or molecule by molecule in order to create materials

Scanning Probe Microscope

  • measures electrical resistance, magnetism, temperature or light absorption with tip positioned extremely close to the sample

Raster Scan Microscope

  • scans the sample while measuring the property of interest

  • data are displayed in raster-scans similar to the TV screen

  • they do not use lenses, so the size of the probe rather the diffraction limits their resolution

  • realistic display

Scanning Tunneling Microscope (STM)

  • developed by Gerd Binnig and Heinrich Rohrer at IBM

  • characterize surface roughness

  • describe texture and surface

  • requires conducting surface like that of a metal layer

Quantum Tunneling Effects

  • electrons behave like wave manner

  • has the ability to pass through energy barrier

  • relationship of the voltage and the current is directly proportional

  • relationship of distance and current is indirectly proportional

Atomic Force Microscope (AFM)

  • invented by Gerd Binnig, Calvin Quate, and Christof Gerber

  • uses reflection of light through laser

  • repulsion and attraction between sample and tip of AFM

Virus Detection via AFM

  • ViriChip detects the presence of virus using AF<

  • a silicon chip is coated with antibodies specific for the virus of interest

  • several different Ab are applied to separate regions of the chip, allowing multiple viruses to be monitored simultaneuosly

Contact Mode

  • short distance between tip and sample

  • cantilever : repelled

  • high resolution ; damage to sample

Non-Contact Mode

  • long distance between tip and sample

  • cantilever : attracted

  • low resolution : no damage to sample

Tapping Mode

  • intermediate

Nanoparticles

  • particles of submicron scale

  • 5nm in size

  • usually spherical but rods, plates, and other shapes are also used

  • central functional layer has somehow magnetic behavior (fluorescence)

  • the water soluble outer layer makes it biocompatible

  • chemicals can be added to allow attachment of biological molecules

Uses

  • fluorescent labeling and optical coding

  • detection of pathogenic microorganism and/or specific proteins

  • purification and manipulation of biological components

  • delivery of pharmaceuticals

  • tumor destruction by chemical or thermal means

  • contrast enhancement in magnetic resonance imagine (MRI)

Nanoparticles for Labeling

  • core of cadmium selenide (CdSe)

  • zinc sulfide - protective layer against oxidation

  • silica to allow coupling of phosphonates or amines to the exterior of the nanorod