Detection of Temperature Difference in Neuronal Cells

Abstract

For a better understanding of the mechanisms behind cellular functions, quantification of the heterogeneity in an organism or cells is essential. Recently, the importance of quantifying temperature has been highlighted, as it correlates with biochemical reaction rates. Several methods for detecting intracellular temperature have recently been established. Here we develop a novel method for sensing temperature in living cells based on the imaging technique of fluorescence of quantum dots. We apply the method to quantify the temperature difference in a human derived neuronal cell line, SH-SY5Y. Our results show that temperatures in the cell body and neurites are different and thus suggest that inhomogeneous heat production and dissipation happen in a cell. We estimate that heterogeneous heat dissipation results from the characteristic shape of neuronal cells, which consist of several compartments formed with different surface-volume ratios. Inhomogeneous heat production is attributable to the localization of specific organelles as the heat source.

Non-Neurotoxic Nanodiamond Probes for Intraneuronal Temperature Mapping

“…Recent studies have identified temperature heterogeneity in neuronal cells, 24 however debate remains about whether biochemical reactions at the single cell level are sufficient to generate such heterogeneity. 35,36 Other forms of temperature variations have been proposed which may accompany current flow in open ionic channels 37 .…”

Local temperatures out of equilibrium

“…An alternative method makes use of spectroscopic techniques, including optical interferometry [359,360], Raman spectroscopy [361] and luminescence [362][363][364][365][366]. The technical details of the above spectroscopic techniques can be found in relevant reviews [367][368][369][370].…”

Characterizing the Quantum-Confined Stark Effect in Semiconductor Quantum Dots and Nanorods for Single-Molecule Electrophysiology

“…Therefore, QDs or NRs with sizable QCSE (at room temperature) that are properly inserted into the cell membrane could report on changes in membrane potential via a spectral shift, a change in the emission intensity, and/or a change in the excited state lifetime. QCSE-based QDs /NRs voltage sensors could also offer several advantages over existing voltage sensors based on organic dyes, fluorescent proteins, or their hybrid: they (1) have high voltage sensitivity (quantified as percent change in fluorescence intensity, ΔF/F), (2) exhibit large spectral shifts (Δλ) enabling ratiometric detection, (3) exhibit changes in excited state lifetime (providing alternative detection scheme), (4) have high brightness affording single-particle detection and superresolution recording, (5) have a fast response time (~ns) based on QCSE, (6) have highly functionalizable surface, (7) have emission wavelength and quantum yield (QY) that can be engineered, (8) have negligible photobleaching, and (9) have low cytotoxicity (after surface modification). With the extremely fast response time, QDs /NRs will be capable of reporting and resolving the APs, which not only have fast dynamics (sub-ms) but also present in a wide range of frequencies and waveforms, especially in mammalian brains [38][39][40][41][42][43] .…”