Study on AgInZnS-Graphene Oxide Non-toxic Quantum Dots for Biomedical Sensing

Abstract

In recent years, non-toxic quantum dot has caught the attention of biomedical fields. However, the inherent cytotoxicity of QDs makes its biomedical application painful, and is a major drawback of this method. In this paper, a non-toxic and water-soluble quantum dot AgInZnS-GO using graphene oxide was synthesized. A simple model of state complex was also established, which is produced through a combination of quantum dots and protein. The interaction between AIZS-GO QDs and human serum albumin (HSA) has significant meaning in vivo biological application. Herein, the binding of AIZS-GO QDs and HSA were researched using fluorescence spectra, Uv-visible absorption spectra, FT-IR spectra, and circular dichroism (CD) spectra. The results of fluorescence spectra demonstrate that AIZS-GO QDs have an obvious fluorescence quenching effect on HSA. The quenching mechanism is static quenching, which implies that some type of complex was produced by the binding of QDs and HSA. These results were further proved by Uv-visible absorption spectroscopy. The Stern-Volmer quenching constant K sv at various temperatures (298 K, 303 K, 308 K) were acquired from analyzing Stern-Volmer plots of the fluorescence quenching information. The Van't Hoff equation could describe the thermodynamic parameters, which demonstrated that the van der Waals and hydrogen bonds had an essential effect on the interaction. FT-IR spectra and CD spectra further indicate that AIZS-GO QDs can alter the structure of HSA. These spectral methods show that the quantum dot can combine well with HSA. The experimental results showed that AgInZn-GO water-soluble quantum dots have good biocompatibility, which can be combined with proteins to form new compounds which have no cytotoxicity and biological practicability. It provides an important basis for the combination of quantum dots and specific proteins as well as fluorescent labeling.

Reversible Transition of Volatile and Nonvolatile Switching in Ag–In–Zn–S Quantum Dot-Based Memristors with Low Power Consumption for Synaptic Applications

“…Additionally, Figure c shows the featureless absorption spectrum of QDs with an absorption onset at about 600 nm. The first excitonic absorption peak is not obvious, which is very common in I–III–VI QDs . Moreover, the photoluminescence (PL) spectrum of the QDs is displayed in Figure d, demonstrating a standard Gaussian profile.…”

“…The first excitonic absorption peak is not obvious, which is very common in I−III−VI QDs. 24 Moreover, the photoluminescence (PL) spectrum of the QDs is displayed in Figure 1d, demonstrating a standard Gaussian profile. It can be clearly seen that the emission maximum is located at 587 nm and the full-width at half-maximum of the PL emission is about 127 nm.…”

“…Quantum dots (QDs) have garnered great interest owing to their unique optical and electronic properties, such as quantum confinement induced outstanding fluorescence, good optical stability, tunable absorption, high mobility for tightly packed QD films, and high surface-to-volume ratio . Recently, QDs have played critical roles in various applications, including light-emitting diodes, biomedical sensing, and RS devices. − Of these, QD-based RS devices have received considerable scientific attention in neuromorphic computing applications due to their ability to improve the uniformity of switching parameters by guiding the orientated growth paths for CFs and to ensure highly reproducible and low-power operation . Quaternary Ag–In–Zn–S (AIZS), a member of the large family of multinary I–III–VI-based semiconductor QDs, has been a focus of research owing to its hypotoxicity, excellent stability, and high carrier mobilities. − However, quaternary AIZS QDs were rarely investigated for memristors and their effects on memristors are still unknown.…”

Biogenesis of Quantum Dots: An Update

“…[4][5][6] Ever since their emergence, QDs have proved to exist a boon in the area of nanotechnology and have led to the unraveling of new horizons in physical and material sciences. In topical years diverse varieties of QDs have played pivotal roles in growth of diverse arenas namely solar cells, [7] transistors, [8] photodetectors, [9] and other optoelectronic devices, [10] LEDs, [11] quantum computing, [12] biomedicine, [13] catalysis, [14] etc.…”

Fluorescence Resonant Energy Transfer-Based Quantum Dot Sensor for the Detection of Calcium Ions

“…In the recent years, quantum dots of various types of composition (Qi et al, 2016 ; Jia et al, 2020 ) have attracted huge attention because of their applicability in a wide variety of biomedical applications (Wegner et al, 2019 ; Song et al, 2020 ). We have successfully detected biomarker proteins like glycated albumin (Ghosh et al, 2017 ) and tumor necrosis factor-alpha (Ghosh et al, 2018 ) using this design strategy.…”