Yoctoliter thermometry for single-molecule investigations: a generic bead-on-a-tip temperature-control module

Area of Science:

• Biophysics
• Physical Chemistry
• Molecular Biology

Background:

• Studying molecular dynamics requires precise temperature control at the single-molecule level.
• Conventional methods can cause photo-damage to delicate biomolecules.
• Accurate in-situ temperature measurement is crucial for thermodynamic analysis.

Purpose of the Study:

• To develop a non-damaging temperature-jump (T-jump) technique for single-molecule experiments.
• To establish a robust method for measuring temperature in situ within micro-scale volumes.
• To obtain the full thermodynamic landscape of DNA hairpin unfolding.

Main Methods:

• A low-intensity laser focused on a black microparticle at a capillary tip generates rapid temperature jumps (T-jumps).
• Photothermal effect achieved with milliwatt lasers, inducing temperature increases of up to 65°C in milliseconds.
• Single-molecule mechanical unfolding of DNA hairpin monitored using optical tweezers.
• In-situ temperature measurement within a yoctoliter volume using a single-molecule thermometer.

Main Results:

• The T-jump strategy successfully avoided photo-damage to individual molecules.
• Precise temperature control was achieved, enabling rapid heating (65°C in milliseconds).
• Full thermodynamic landscapes for DNA hairpin unfolding were successfully retrieved.
• The integrated system demonstrated a robust single-molecule thermometer.

Conclusions:

• The developed T-jump strategy offers a powerful tool for studying molecular dynamics.
• Combining T-jump with single-molecule techniques allows for microanalytical investigations.
• This approach is suitable for detailed thermodynamic analysis of biomolecular processes.
• The method minimizes sample damage, preserving molecular integrity during experiments.