Cellular Thermometry Considerations for Probing Biochemical Pathways

Manjunath C. Rajagopal, Sanjiv Sinha

Research output: Contribution to journalArticlepeer-review

Abstract

Temperature is a fundamental thermodynamic property that can serve as a probe of biochemical reactions. Extracellular thermometry has previously been used to probe cancer metabolism and thermoregulation, with measured temperature changes of ~1–2 K in tissues, consistent with theoretical predictions. In contrast, previous intracellular thermometry studies remain disputed due to reports of >1 K intracellular temperature rises over 5 min or more that are inconsistent with theory. Thus, the origins of such anomalous temperature rises remain unclear. An improved quantitative understanding of intracellular thermometry is necessary to provide a clearer perspective for future measurements. Here, we develop a generalizable framework for modeling cellular heat diffusion over a range of subcellular-to-tissue length scales. Our model shows that local intracellular temperature changes reach measurable limits (>0.1 K) only when exogenously stimulated. On the other hand, extracellular temperatures can be measurable (>0.1 K) in tissues even from endogenous biochemical pathways. Using these insights, we provide a comprehensive approach to choosing an appropriate cellular thermometry technique by analyzing thermogenic reactions of different heat rates and time constants across length scales ranging from subcellular to tissues. Our work provides clarity on cellular heat diffusion modeling and on the required thermometry approach for probing thermogenic biochemical pathways.

Original languageEnglish (US)
Pages (from-to)359-373
Number of pages15
JournalCell Biochemistry and Biophysics
Volume79
Issue number2
DOIs
StatePublished - Jun 2021

Keywords

  • Cellular metabolism
  • Design of experiments
  • Heat diffusion
  • Interfacial resistance
  • Intracellular thermometry
  • Thermal conductivity

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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