Fabrication and characterization of thermocouple probe for use in intracellular thermometry

Manjunath C. Rajagopal, Krishna V. Valavala, Dhruv Gelda, Jun Ma, Sanjiv Sinha

Research output: Contribution to journalArticlepeer-review


Measuring temperatures within a biological cell requires a sensor with small thermal mass and microscale or smaller size that is electrically and chemically inert to the cell's environment, and is thermally isolated from the surroundings. We investigate how such requirements can be satisfied in a microscale thermocouple probe that is fabricated using the techniques of silicon-based microelectromechanical systems. Previous reports of invasive probes lacked either the required spatial resolution (<5 μm) or response time (<4 ms). Here, we report 1 μm thick silicon nitride supported probes with a 5 μm tip that has a response time of 32 μs. These figures enable future transient thermometry of cell organelles. To reduce calibration errors, we devise an on-chip calibration in a vacuum cryostat. We find that the accuracy of our measurements is ±54 mK for 300 ± 10 K. This work paves the way toward future thermometry at a subcellular level.

Original languageEnglish (US)
Pages (from-to)253-258
Number of pages6
JournalSensors and Actuators, A: Physical
StatePublished - Apr 1 2018


  • Intracellular measurements
  • Microelectromechanical systems
  • Sensors
  • Thermocouple

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering


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