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Advanced Neurology Graphene quantum dots approach in AD

infrared detectors, and solar cells. However, the shell of a nanoparticles, having properties of both QDs and
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QD consists of a wide-gap semiconductor – such as zinc grapheme. Due to their exceptional electro-optical
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sulfide or cadmium sulfide – which passivates any surface properties, biocompatibility, non-toxicity, and chemical
defects and enhances quantum yield, thereby improving stability, GQDs demonstrate excellent performance
the stability and functionality of QDs. This core–shell across various fields, such as biotechnology, electronics,
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configuration significantly enhances the performance of and medicine. 23-28 Typically, GQDs have a size of <20 nm
QDs, allowing them to be used in various applications. in diameter. The quantum confinement effect becomes
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Hence, QDs are suitable for biological applications, including more noticeable as the size of the dot decreases and
medical imaging and biosensors, due to their nature and approaches the bulk exciton’s Bohr radius. In GQDs,
size, which allow them to circulate throughout the body. the excitons have a limitless Bohr diameter, making the
Moreover, QDs are widely used in tumor targeting, in vivo quantum confinement effects more visible in graphene
observation of cell trafficking, intracellular process studies, fragments of varying sizes. Thus, GQDs have exceptional
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diagnostics, and high-resolution cellular imaging. Their optoelectronic properties and are considered more
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high quantum yield, photostability, and tunable emission desirable than other forms of QDs. Compared to graphene,
spectrum make them significantly superior to conventional GQDs have a tunable, non-zero band gap and fluorescence
organic dyes. Compared to traditional fluorescent dyes, upon excitation. This band gap is tunable by altering the
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QDs are approximately 20 times brighter and 100 times surface chemistry and size of the QD. Another distinctive
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more stable. Li et al. reported that QDs can be surface- feature of GQDs is electrochemiluminescence, where
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functionalized to improve their solubility, stability, and they emit luminescence during electrochemical reactions.
biocompatibility for certain uses. QDs also have exceptional According to Eda et al., the electrical properties of
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photostability, making them perfect for applications in GQDs can change depending on their size. GQDs are
extremely sensitive cellular imaging. This facilitates the also known for their absorption and photoluminescence
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high-resolution reconstruction of multiple successive focal- characteristics, 21,32,33 which make them highly applicable
plane images into three-dimensional images. By employing in bioimaging, biosensing, and optoelectronics. 35,36
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peptides, antibodies, or ligands to target particular cells or Furthermore, due to their low toxicity, high bioavailability,
proteins, QDs can be used to examine the target protein or excellent solubility in a wide range of solvents, and their
the behavior of the cells.
ability to be equipped with functional groups, GQDs are
Table 1 classifies the properties of quantum dots based considered more desirable for applications in various fields
on factors influenced by their core and shell components. such as biology and medicine. The synthesis of GQDs
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involves various methods, broadly classified into top-
3. GQDs down and bottom-up approaches. Each method impacts
Graphene is a semiconductor with zero bandgap and the size, functionalization, and optical properties of the
infinite exciton Bohr diameter. GQDs are graphene resulting GQDs, thereby affecting their applicability.
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Table 1. Properties of quantum dots based on their core and shell components
Components Properties Significance
Core (determines Strong fluorescence and light emission Quantum confinement results in strong fluorescence
the electrical and Size tunability Emission wavelength varies with core size
optical properties)
High quantum yield Efficient photon emission with minimal losses
Photoluminescence properties Core material governs light emission after excitation
Electrochemiluminescence Core structure contributes to electrochemical light emission
Absorption Strong ultraviolet-visible absorption due to quantum confinement
Shell (enhances the Photostability Protects the core from photobleaching and degradation
stability and surface Chemical stability Prevents oxidation and enhances durability
interactions)
High solubility in a range of solvents Surface modifications improve dispersion in various media
Ease of synthesis Proper shell engineering enhances processability
Biocompatibility Shell design determines its safety for biological applications
Bioavailability Functional shells improve biological retention and distribution
Surface functionalization The ability to be equipped with functional groups enables targeting and improved solubility.

Volume 4 Issue 4 (2025) 19 doi: 10.36922/an.7087