Molecular Interaction Analysis |
Implementation |
Interpretation |
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Label-free, binding constant, kinetics, molecular interaction, SPR, optical resonance, whispering gallery mode |
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Label-free molecular interaction analysis using optical resonance.
Real-time biosensing similar to SPR (surface plasmon resonance):
Binding constants and kinetics of molecules interacting with surface-immobilized ligands can be determined in real time without any labels.
Advantages compared to other techniques (i.e.SPR/QCM):
highest sensitivity
sensitive towards molecular orientation
quantitative (molecular weight, surface densities and polarizabilities can be
determined directly)
Please refer to http://www.rowland.harvard.edu/rjf/vollmer/images/limit_new.pdf
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| Usual measurement | Exotic measurements | |
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Record change of the resonance wavelength of an optical microsphere cavity Comments |
Anisotropic measurements by tracking the change of resonance wavelength of TE (transverse electric) and TM (transverse magnetic) modes Gaging the thickness of an adsorbed layer by measuring the resonce wavelength change for two different wavelength Comments |
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sensitivity: 1 pg/mm2 mass loading on sensing are (corresponds to 1 RU in SPR instruments)
small: microsphere sensors are typically ~200 um radius
fast: data can be acquired >MHz
referenced: measurements can be referenced
Comments |
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Current-tunable DFB laser is connected to optical fiber. Transmission spectrum is acquired with photodetector at the other fiber end. A microsphere is in mechanical contact with a tapered portion of the optical fiber. Resonances appear in the transmission spectrum as Lorentzian-shaped dips. A computer program tracks the dip position over time. Please
refer to http://www.rowland.harvard.edu/rjf/vollmer/images/aplwgmb.pdf
Comments |
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Chiral discrimination when implemented as ring-resonator.
Possible displacement sensor when implemented as fiber ring-resonator. Comments |
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http://www.rowland.harvard.edu/rjf/vollmer/index.php3 Comments |
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http://www.rowland.harvard.edu/rjf/vollmer/pubs.php Comments |
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rowland.harvard.edu