The advancement of optical methodologies applied to biological systems, such as ultrafast optical spectroscopy and single-molecule fluorescence spectroscopy, has provided new experimental observations suggesting that non-trivial quantum effects influence biological processes. In addition, recent observations in engineered fluorescent proteins amenable to quantum biological studies invite us to explore systematic approaches in studying biological quantum phenomena at the molecular level. These technical advances and scientific applications lead an exciting and emerging research area: Quantum Biophotonics.
About our work
The work in our Quantum Biophotonics Laboratory is focused on:
- Understanding how evolution has shaped biological systems that allow non-trivial quantum effects in biology,
- Identification of new model systems for the study of quantum biology
- Development of new quantum-bio-inspired technologies.
Quantum mechanics has transformed our understanding of nature on an atomic scale and has been applied to many research areas and applications such as quantum information science and quantum computing in which experiments have been typically conducted in a carefully controlled laboratory environment. This is because quantum effects are fragile, i.e. random molecular interactions should obliterate quantum coherent molecular interactions in a warm and wet environment.
Evidence has been accumulated in recent years that non-trivial quantum effects may play a role in macromolecular interactions influencing biological processes. This is an exciting and emerging area of science that has recently gained huge attention. However, both developing experimental techniques and tractable biological systems amenable to investigating how nature maintains quantum effects in a warm, wet environment are urgently needed to resolve the many controversies in this field.
Quantum coherence effects within fluorescent protein (FP) at room temperature were thought to be impossible because close fluorophore proximity is limited by the FP ß-barrel structure, and the system-environment interactions at room temperature typically promote rapid vibrational decoherence . Nonetheless, anomalous FPs behaviours have recently been observed in several studies suggesting that these fluorophores might have unique photophysical properties that preserve quantum effects under physiological conditions. For instance, it was observed that the dephasing time of green fluorescent protein (GFP) was measured to be about 1 ps , much longer than expected decoherence time of ~10 fs . In addition, the generation of a polarization-entangled two photon state in enhanced GFP  and strong photon antibunching together with Davydov-splitting has been observed in homodimers of the YPF VenusA206  have recently been reported. These results strongly support the hypothesis that FPs have evolved to maintain quantum effects under physiological conditions and might therefore have unique photophysical behaviours.
Thus, ultrafast optical spectroscopy of FPs can be used to extend our fundamental understanding of how nature can exploit quantum effects at ambient temperatures. They may also inspire new quantum-bio-inspired technologies such as the development of low-cost quantum computers or single-photon sources operating at room temperature.
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- Cinelli, R.A., et al., Coherent dynamics of photoexcited green fluorescent proteins. Physical review letters, 2001. 86(15): p. 3439.
- Shi, S., P. Kumar, and K.F. Lee, Generation of photonic entanglement in green fluorescent proteins. Nature communications, 2017. 8(1): p. 1-7.
- Kim, Y., et al., VenusA206 Dimers Behave Coherently at Room Temperature. Biophysical journal, 2019. 116(10): p. 1918-1930.