BEH. 462/3.962J Molecular Principles of Biomaterials Spring 2003 Excitation of bar-code and target fluorochrome by same wavelength 1 Gow. Figure 5. Schematic illustration of DNA hybnidization assays using spectrophotometer for detection Cascade Blue. After hybridization, nonspecific molecules and excess reagents were of emission spectra from individual bead and hybridization kinetics(30 min). See legend in Figure 6 for the sequences used ptical absorption Surface plasmon resonance and SPR arra Developed commercially later 1980,s(Cooper 2002) Typically, receptor is immobilized and free ligand is passed over sensor chip Both ways possible, small ligands simply interfere with binding if immobilized Flow channa Box 2 Couping methods for reeeptor immobih Senso chp Bit ior Mrpa ii-l septum a). The alt Rom - tiny tes ef streptase eflected epitope FLAG etape an ea His I ai( have boom widcly uod for diet derale decay in the lrdl ed crocrgram Figure 2 Typical set-up for an SPR biosensor, Surface smon resonance(SPR) detects changes in the refractve dex In the mmerllata wcinty of the sl rtane layer ot a sanor chip SPR 0=° observed as a sharp shadow h the reflected Ight from the surface at anange that s dependent on the mass of materal at the surface. The SPR angle shfts (from I to ll inthe bwer left-hand diagram) when biomolecules bind to the surtace and hange the mass of the surtace layer. This change in resonant ange can be monitored non-invaslely in real time as a pbt of resonance signal (proportiona to mass change) versus time. (Cooper 2002) Lecture 19-BiosensorsBEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Excitation of bar-code and target fluorochrome by same wavelength Microscope-based spectrophotometer for detection of emission spectra from individual beads ƒ Optical absorption (colorimetric) • what ƒ Surface plasmon resonance and SPR arrays • Developed commercially later 1980’s (Cooper 2002) • Typically, receptor is immobilized and free ligand is passed over sensor chip ƒ Both ways possible, small ligands simply interfere with binding if immobilized (Cooper 2002) Lecture 19 – Biosensors