1. Principles of FRET – Based (Bio) Sensors
Nanoscience Symposium 2005
Auke Jisk Kronemeijer

2. Introduction Need for sensitive, reusable measurement devices
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Introduction
Need for sensitive, reusable measurement devices
Specific molecular detection
Specific detection of activities
Towards in vivo detection

3. Interesting Principle For Sensors is FRET
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Interesting Principle For Sensors is FRET
Fluorescence / Förster Resonance Energy Transfer
Why FRET ?
-Distance and Spectral Overlap dependences
Possibility for Processing in Integrated Circuits

4. General Principles of Resonance Energy Transfer
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
General Principles of Resonance Energy Transfer
- Radiative vs non-radiative
- Two models for non-radiative
Förster
Dexter

5. General Principles of Resonance Energy Transfer
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
General Principles of Resonance Energy Transfer
- Detection of FRET
- Quantitative Detection Difficulties
Spectral Bleed-Through
Acceptor excitation by donor excitation wavelenght
Cross Talk
Donor Emission Contribution to FRET Emission

6. FRET Based Recognition Biosensor
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
FRET Based Recognition Biosensor
- Modified Biomolecule for Specificity

7. Problems with Molecular Principle
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Problems with Molecular Principle
Large spectral bleed-through and cross-talk
Difficult to find good / compatible pairs

8. Solutions to Spectral Bleed-Through
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Solutions to Spectral Bleed-Through
Photochromic FRET
“Switching on and off FRET mechanism to determine FRET contribution to total emission”

9. Solutions to Spectral Bleed-Through
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Solutions to Spectral Bleed-Through
Use Quantum Dots as Donors
Advantages:
Broad absorption
Narrow Emission
Size tunability
Surface functionalisation

10. Quantum Dot FRET Based Recognition Sensor
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Quantum Dot FRET Based Recognition Sensor
Possibility for Templating
AFM Image of Si8Ge2 QD´s on Si(100)

11. Sensors Based on Distance Changes
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Sensors Based on Distance Changes
Enzyme Activity Sensors
Reminder:

12. Recognition Sensor based on Isomerisation
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Sensors Based on Distance Changes
Determination of Isomerisation
Recognition Sensor based on Isomerisation
If Initiator / Target is Present, FRET Efficiency Changes

13. Conclusions Many different sensors possible with use of FRET
Principles of FRET – Based (Bio) Sensors - Nanoscience Symposium 2005
Conclusions
Many different sensors possible with use of FRET
Use of Quantum Dots as Donor Promising
Innovative Solutions Come Up for Quantitative Measurements