細胞内小器官の熱伝導率を初めて定量化 ─センサより小さな領域の熱分析を可能にする技術を開発─

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2026-03-25 東北大学

本研究は、東北大学の猪股直生らが、細胞内の微小領域における熱の性質を定量化する新技術を開発し、細胞内小器官(オルガネラ)の熱伝導率を初めて実験的に評価した成果である。透明なマイクロ温度センサアレイで取得した温度データと蛍光観察画像を統合し、熱拡散方程式に基づく逆解析を行うことで、センサより小さい領域の熱特性を推定する手法を確立した。さらに、核やミトコンドリアなど各オルガネラで熱伝導率が最大となる温度が異なることを明らかにし、細胞内での熱輸送における役割分担の可能性を示した。本成果は細胞内熱現象の理解や生体機能解明に貢献することが期待される。

細胞内小器官の熱伝導率を初めて定量化 ─センサより小さな領域の熱分析を可能にする技術を開発─
図1. 実測データと数理モデルを融合した分析技術の概要。マイクロ温度センサアレイで取得した温度情報と、蛍光観察で取得したオルガネラの位置情報を熱拡散方程式に組み込み、オルガネラの熱伝導率を推定する。

<関連情報>

透明マイクロサーミスタアレイにより、生細胞内の細胞小器官レベルの熱伝導率推定が可能に Transparent Micro-Thermistor Array Enables Organelle-Resolved Thermal Conductivity Estimation in Living Cells

Naoki Inomata, Kaito Suzuki
Sensors and Actuators Reports  Available online: 10 March 2026
DOI:https://doi.org/10.1016/j.snr.2026.100461

Highlights

  • A transparent micro-thermistor array enables multisite cellular temperature sensing.
  • Simultaneously, the sensor array is compatible with fluorescence imaging of organelle structures.
  • Inverse thermal analysis allows estimation of organelle-specific thermal conductivities Temperature-dependent thermal conductivities reflect structural heterogeneity in cells.

Abstract

Quantitative determination of heat flow through subcellular structures is essential for understanding intracellular heat transport and the thermophysical properties of living cells. However, organelle-resolved thermal properties cannot be measured because existing intracellular thermometry techniques either perturb cells with exogenous probes or lack the spatial resolution required for organelle-scale analysis. To overcome these limitations, we developed a transparent vanadium dioxide (VO₂) micro-thermistor array that enables simultaneous, multisite temperature measurements in one to several adherent cells while maintaining full compatibility with fluorescence microscopy. This micro-thermistor array uniquely integrates transparent VO₂ thermistors with fluorescence-compatible microfabrication, enabling the estimation of organelle-resolved thermal conductivity through thermal-circuit-based inverse analysis. The six-element array, fabricated on a quartz substrate with indium tin oxide (ITO) electrodes, exhibited a temperature coefficient of resistance of 1.51%°C⁻¹, temperature resolution of 8.8 m°C, and sufficient visible transmittance for confocal fluorescence imaging. By integrating dynamic temperature responses under localized IR laser heating with three-dimensional fluorescence images of nuclei, mitochondria, cytoplasm, and other organelles, we constructed a thermal-circuit model and performed inverse analysis to estimate the thermal conductivities of individual organelles. The resulting organelle-level conductivities reflected known intracellular organization, showed distinct temperature dependence at 25°C, 37°C, and 45°C, and yielded effective whole-cell thermal conductivities of 0.55–0.70 W m⁻¹ K⁻¹, consistent with previously reported single-cell values. These findings demonstrate that transparent micro-thermistor arrays function as probe-free sensors enabling organelle-resolved estimation of intracellular thermal properties, establishing a quantitative sensing platform for the systematic analysis of heat transport and thermoregulation in living cells.

生物環境工学
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