Nanothermometry: From Microscopy to Thermal Treatments

Abstract

Measuring temperature in cells and tissues remotely, with sufficient sensitivity, and in real time presents a new paradigm in engineering, chemistry and biology. Traditional sensors, such as contact thermometers, thermocouples, and electrodes, are too large to measure the temperature with subcellular resolution and are too invasive to measure the temperature in deep tissue. The new challenge requires novel approaches in designing biocompatible temperature sensors-nanothermometers-and innovative techniques for their measurements. In the last two decades, a variety of nanothermometers whose response reflected the thermal environment within a physiological temperature range have been identified as potential sensors. This review covers the principles and aspects of nanothermometer design driven by two emerging areas: single-cell thermogenesis and image guided thermal treatments. The review highlights the current trends in nanothermometry illustrated with recent representative examples.

Temperature and Phase Transition Sensing in Liquids with Fluorescent Probes

“…The ability to control and monitor the temperature at real time and with high precision is required in vast number of applications. Several techniques of micro-and nanothermometry [1] have been developed in order to monitor properties of very small objects. In particular, inapplicability of conventional methods, such as thermocouple measurements or infrared thermography for temperature studies on micro-and nano-scales, has led to search for alternative probes.…”

Optical Properties of Hybrid Organic‐Inorganic Materials and their Applications

“…[118] Luminescent thermometry exploits the temperature dependence of the light emission features of the thermometric probes, namely emission intensity, [119][120][121] peak position, [122] and excited-states lifetime [123,124] or risetime, [125,126] possessing the unique advantage of high-resolution contactless measurement, even in harsh environments and under strongly electromagnetic fields. [127][128][129][130] Although relatively recent (luminescent thermometry exploded over the past five years), the technique appears to be beneficial to many technological applications in a great variety of areas, such as microelectronics, microfluidics, bio-and nanomedicine. [131] Examples of luminescent thermometers based on organic-inorganic hybrids include metal-organic molecular compounds, [132] layer double hydroxides, [133] metalorganic frameworks, [134] polymer nanocomposites, [135] QDs in polymers, [136] inorganic NPs coated with an organic (or hybrid) layer, [137] and di-ureasil films co-doped with Eu 3+ and Tb 3+ $-diketonate complexes.…”

Universal guidelines for the conversion of proteins and dyes into functional nanothermometers

“…Biocompatible nanothermometers could only be developed by joining the efforts of those in the fields of chemistry, physics and biology. Nanothermometers are capable of reporting real‐time nanoscale temperature changes in a wide range of biological environments, including both intracellular and extracellular spaces (see recent reviews by Quintanilla and Marzan and Okabe et al and Zhou et al ). They can be categorized in two main groups, based on their need for direct contact with the environment .…”

“…This approach allows the modified proteins to retain their native structure and activity, while simultaneously transmitting temperature information via a change in fluorescence polarization . Thus far, ABNTs have been shown to measure intracellular temperature in a wide variety of biological systems, ranging from cells in vitro , to whole live organisms and microfluidic systems . So far, only a few proteins have been tested as nanothermometers, limiting their usefulness in diverse biological systems .…”