A Nanoheater-Integrated Fluorescence Lifetime Thermometer for Investigating Subcellular Heat Shock Factor 1 Responses
- 1WPI Nano Life Science Institute, Kanazawa University
Abstract
Subcellular thermal engineering provides a powerful approach for investigating and manipulating biological processes. However, existing subcellular heating platforms capable of combining spatially confined heating, quantitative thermometry and simultaneous imaging of cellular responses remain limited. We developed a quantitative nanoheater-thermometer (qNanoHT), a polymeric nanoparticle integrating a temperature-sensitive fluorescent, dye and a photothermal dye. qNanoHT determines local temperature from fluorescence lifetime using fluorescence lifetime imaging microscopy (FLIM), thereby reducing susceptibility to photobleaching, focal drift and variations in probe concentration compared with intensity-based methods. The platform enabled real-time measurement at a subcellular heat spot while the dynamics of heat shock factor 1 (HSF1) were monitored in living cells. Heating at a single intracellular site was sufficient to induce HSF1 foci. Foci induced by mild heating at approximately 38 {degrees}C dissolved after heating ceased, whereas those induced by stronger heating at approximately 41 {degrees}C persisted and were associated with caspase-3/7 activation and apoptosis. Notably, qNanoHT-mediated subcellular heating induced HSF1 foci at a lower measured temperature than uniform whole-cell heating approximately 38 {degrees}C versus 39 {degrees}C indicating that the spatial extent of heating influences the HSF1 activation threshold. qNanoHT therefore provides a quantitative platform for relating local intracellular temperature to cellular stress responses and subsequent cell fate.
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BibTeX
@misc{nisansala2026nanoheaterintegrated,
title = {{A Nanoheater-Integrated Fluorescence Lifetime Thermometer for Investigating Subcellular Heat Shock Factor 1 Responses}},
author = {H. D. Nisansala and D. Basnayake and K. Nomura and Y. Kono and T. Yamazaki and Y. Matsuda and C. Q. Vu and T. Shimi and S. Arai},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.02.748709},
url = {https://www.biorxiv.org/content/10.64898/2026.09.02.748709v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A Nanoheater-Integrated Fluorescence Lifetime Thermometer for Investigating Subcellular Heat Shock Factor 1 Responses
AU - H. D. Nisansala
AU - D. Basnayake
AU - K. Nomura
AU - Y. Kono
AU - T. Yamazaki
AU - Y. Matsuda
AU - C. Q. Vu
AU - T. Shimi
AU - S. Arai
PY - 2026
DA - 2026/09/02
PB - bioRxiv
DO - 10.64898/2026.09.02.748709
UR - https://www.biorxiv.org/content/10.64898/2026.09.02.748709v1
AB - Subcellular thermal engineering provides a powerful approach for investigating and manipulating biological processes. However, existing subcellular heating platforms capable of combining spatially confined heating, quantitative thermometry and simultaneous imaging of cellular responses remain limited. We developed a quantitative nanoheater-thermometer (qNanoHT), a polymeric nanoparticle integrating a temperature-sensitive fluorescent, dye and a photothermal dye. qNanoHT determines local temperature from fluorescence lifetime using fluorescence lifetime imaging microscopy (FLIM), thereby reducing susceptibility to photobleaching, focal drift and variations in probe concentration compared with intensity-based methods. The platform enabled real-time measurement at a subcellular heat spot while the dynamics of heat shock factor 1 (HSF1) were monitored in living cells. Heating at a single intracellular site was sufficient to induce HSF1 foci. Foci induced by mild heating at approximately 38 {degrees}C dissolved after heating ceased, whereas those induced by stronger heating at approximately 41 {degrees}C persisted and were associated with caspase-3/7 activation and apoptosis. Notably, qNanoHT-mediated subcellular heating induced HSF1 foci at a lower measured temperature than uniform whole-cell heating approximately 38 {degrees}C versus 39 {degrees}C indicating that the spatial extent of heating influences the HSF1 activation threshold. qNanoHT therefore provides a quantitative platform for relating local intracellular temperature to cellular stress responses and subsequent cell fate.
ER -