A White Light‐Emitting Quantum Dot Complex for Single Particle Level Interaction with Dopamine Leading to Changes in Color and Blinking Profile

Abstract

The interaction of the neurotransmitter dopamine is reported with a single particle white light-emitting (WLE) quantum dot complex (QDC). The QDC is composed of yellow emitting ZnO quantum dots (Qdots) and blue emitting Zn(MSA) complex (MSA = N-methylsalicylaldimine) synthesized on their surfaces. Sensing is achieved by the combined changes in the visual luminescence color from white to blue, chromaticity color coordinates from (0.31, 0.33) to (0.24, 0.23) and the ratio of the exponents (α /α ) of on/off probability distribution (from 0.24 to 3.21) in the blinking statistics of WLE QDC. The selectivity of dopamine toward ZnO Qdots, present in WLE QDC, helps detect ≈13 dopamine molecules per Qdot. Additionally, the WLE QDC exhibits high sensitivity, with a limit of detection of 3.3 × 10 m (in the linear range of 1-100 × 10 m) and high selectivity in presence of interfering biological species. Moreover, the single particle on-off bilking statistics based detection strategy may provide an innovative way for ultrasensitive detection of analytes.

Engineering Quantum Dots with Ionic Liquid: A Multifunctional White Light Emitting Hydrogel for Enzyme Packaging

“…Engineering the surface of luminescent quantum dots (QDs) plays a significant role in altering their physicochemical properties such as emission characteristics, stability, and solubility, which in turn affects their utility in biological and optoelectronic applications 1–7. Various surface modifying strategies such as ion exchange, ligand exchange, and complexation have been reported to improve the optical performance of QDs in numerous applications, such as light‐emitting devices (LEDs), biological imaging, optical sensors, and other energy devices of QDs 1–7. For example, modification of the surface of QDs with a luminescent inorganic complex helped to fabricate an environmentally sustainable WLE composite that showed a perfect white light nature, which has applications in neurotransmitters and reversible pH sensing 5–7.…”

“…Various surface modifying strategies such as ion exchange, ligand exchange, and complexation have been reported to improve the optical performance of QDs in numerous applications, such as light‐emitting devices (LEDs), biological imaging, optical sensors, and other energy devices of QDs 1–7. For example, modification of the surface of QDs with a luminescent inorganic complex helped to fabricate an environmentally sustainable WLE composite that showed a perfect white light nature, which has applications in neurotransmitters and reversible pH sensing 5–7. Overall, the action of a surface‐modifying agent is crucial for the successful fabrication of a luminescent composite demanded by an end‐use application.…”

“…Fabrication of a highly efficient and stable WLE composite, with properties close to bright daytime light, is of paramount interest because of the growing demand for energy‐efficient lighting and display systems 5–10. In general, WLE systems are fabricated either by i) mixing red‐, green‐, and blue‐emitting QDs, which are toxic metal‐based or ii) using expensive and multi‐step surface modification strategies 5–10. However, their uses are limited due to the problems linked to nonradiative energy transfer, unwanted changes in chromaticity, self‐absorption, high cost, and low environmental sustainability 5–10.…”

“…In general, WLE systems are fabricated either by i) mixing red‐, green‐, and blue‐emitting QDs, which are toxic metal‐based or ii) using expensive and multi‐step surface modification strategies 5–10. However, their uses are limited due to the problems linked to nonradiative energy transfer, unwanted changes in chromaticity, self‐absorption, high cost, and low environmental sustainability 5–10. Thus, the inexpensive and eco‐friendly surface modification strategies and agents have received the most attention for fabricating highly efficient WLE composites.…”

Few Particle-Level Chromaticity Index-Based Discrimination of Biothiols Using Chemically Interactive Dual-Emitting Nanoprobe

“…Thus, designing newer principles of sensing by combination of both these options, i.e., "a few particle"-level luminescence change in a multichromic luminophore, may offer the best of both choices. 12 This becomes even more important when the challenge of discriminating between chemically analogous compounds is at hand. It is noteworthy that in such cases, a distinction between two analogous analytes is mainly done on the basis of the "extent" of a similar interaction with the sensor, 13 which may not necessarily offer the best degree of precision in the detection process.…”