Tunable Carbon-Dot-Based Dual-Emission Fluorescent Nanohybrids for Ratiometric Optical Thermometry in Living Cells

Abstract

The use of carbon-dot-based dual-emission fluorescent nanohybrids (DEFNs) as versatile nanothermometry devices for spatially resolved temperature measurements in living cells is demonstrated. The carbon dots (CDs) are prepared in the organic phase and display tunable photoluminescence (PL) across a wide visible range by adjusting the excitation wavelengths and extend of N-doping. DEFNs are formed in a straightforward fashion from CDs (emitting blue PL) and gold nanoclusters (AuNCs, emitting red PL). The DEFNs display ideal single-excitation, dual-emission with two well-resolved, intensity-comparable fluorescence peaks, and function in optical thermometry with high reliability and accuracy by exploiting the temperature sensitivity of their fluorescence intensity ratio (blue/red). Furthermore, the DEFNs have been introduced into cells, exhibiting good biocompatibility, and have facilitated physiological temperature measurements in the range of 25-45 °C; the DEFNs can therefore function as "non-contact" tools for the accurate measurement of temperature and its gradient inside a living cell.

Green Synthesis of Red‐Emitting Carbon Nanodots as a Novel “Turn‐on” Nanothermometer in Living Cells

“…To this end, intracellular temperature sensing using fluorescent materials represents a potentially useful tool for real‐time and in vivo monitoring of important cellular analytes . Recently, amounts of fluorescent probes have been developed for the measurement of temperature, such as fluorescent dyes, fluorescent polymer nanoparticles, semiconductor quantum dots (SQDs), carbon dots and metal nanoclusters (NCs) . Among them, although SQDs and NCs exhibit size‐tunable emission, small size, high photostability and quantum yields, and large Stokes shifts, serious toxicity or difficult commercial availability, or very broad emission spectra limited their further applications .…”

Red C-dots and C-dot films: solvothermal synthesis, excitation-independent emission and solid-state-lighting

“…[13][14][15][16][17] Therefore, it is highly desirable to develop CDs with intense and stable red emission. Furthermore, the conversion from CD solution into carbon solid-state powder is urgently required.…”

Ultrahigh-sensitive optical temperature sensing based on quasi-thermalized green emissions from Er:ZnO

“…3g. Each of the curves is fitted to the Equation 4 and Ea is found to be within 201.8 and 257.5 meV (Table 1). We also analyze the variation of the integral peak intensity ratio of 540 and 565 nm peaks and obtain E/k in 3100 and 3445 K range (Table 1).…”

“…1,2 In this regard, accurate determination of temperature in the nano/micro scale regime, especially in microelectronic circuits, living cells, etc., [3][4][5][6][7][8] is essential to use noncontact optical based thermometers, which have its own advantages over conventional temperature measuring devices due to its noninvasive operations and inertness to various environment such as electrical or magnetic field or other harsh environments in the desired circumstances. [9][10][11] Among various optical thermometers, temperature induced change in different fluorescence parameters such as emission intensity, fluorescent intensity ratio (FIR), peak position, peak width, life time, etc.…”