Semiconductor nanoparticles known as Quantum Dots (QDs) have special optical and electrical characteristics because often falling between 2 and 10 nm in size nano meters (Al-Douriet al., 2023). At this scale, QDs exhibit quantum mechanical effects, particularly quantum confinement, where the motion of electrons is restricted to discrete energy levels. This quantum confinement leads to size-dependent optical properties, meaning QDs’ light can have a variety of colours. precisely managed by changing the magnitude of (Sarkar, 2023). Light is emitted at shorter wavelengths by smaller QDs. (blue), bigger QDs, however, release light at longer wavelengths (red). These properties make QDs highly valuable in various applications (Huanget al., 2020). In optical and electronic devices, their tuneable emission spectra and high brightness are leveraged for displays, solar cells, and LEDs. In biomedical fields, QDs are prized for their stability and superior fluorescence compared to traditional dyes, enabling advanced imaging techniques (Jiaoet al., 2022). They allow for multicolour imaging and can be functionalized with biological molecules for targeted imaging and 1. Optimised Permeability and Retention Impact through Passive Targeting efficiency and versatility, providing significant advantages over conventional materials (Augustineet al., 2021). Despite their potential, ongoing research is crucial to address their cytotoxicity and ensure safe implementation in medical and environmental applications (Ramburrunet al., 2022).

While the idea of Quantum Dots (QDs) emerged in the 1980s when researchers began to explore the effects of quantum confinement on semiconductor materials (Kambhampatiet al., 2021). “Quantum dot” was the phrase used to first created by physicist Mark Rees in 1982, who along with his colleagues, demonstrated the quantum confinement effect in nanostructures (Wanget al., 2020). This effect occurs when the dimensions of the semiconductor are lowered to a size similar to the Bohr radius of an exciton, leading to discrete energy levels similar to those in atoms (Böeret al., 2023). One of the pioneering discoveries in the field was made by Louis Brus in 1983 at Bell Laboratories, where colloidal synthesis methods were developed to produce Cadmium Selenide (Cd Se) quantum dots (Hao, 2020). Brus’s work highlighted The dimensions and optical characteristics of these nanoparticles, marking a significant advancement in nanotechnology (Khanet al., 2022). In the 1990s, further development was spurred by creating superior-grade quantum dots using better control over the dimensions and topography properties, notably by the group of Paul Alivisatos and Moungi Bawendi (Reddyet al., 2024). Their contributions enabled the QDs’ practical use in a variety of sectors, including biology as well optoelectronics (Yoonet al., 2021). As the commercial and scientific interest in quantum dots has since grown exponentially, driven by their potential in creating more efficient solar cells, displays, and biomedical imaging technologies. Today, quantum dots continue to be a vibrant area of research, promising innovations in multiple technological domains (Garcíaet al., 2021).

The role of Quantum Dots (QDs) increasingly pivotal part of the nanotechnology and medical fields because of their distinct optical and electrical characteristics (Shaoet al., 2020). In which realm that of the nanotechnology, QDs are revolutionizing display technologies with their use in QLED (Quantum Dot Light-Emitting Diode) televisions, offering superior colour accuracy, brightness, as well as energy conservation compared as well traditional LCD in addition to OLED displays (Abbaset al., 2024). Their highly quantifiable emission frequencies and yield manufacture them ideal for creating vivid, lifelike visuals (Zhaoet al., 2020). In solar energy, QDs are improving solar energy cells’ efficiency (AlGhamdiet al., 2020). By tailoring that absorption properties of QDs, researchers are developing solar cells that can harness a broader spectrum of sunlight, potentially surpassing the efficiency of conventional silicon-based solar cells (Gong, 2024). In medicine, QDs are transforming imaging and diagnostic techniques (Deviet al., 2022). Their high brightness, photostability, and size-tuneable fluorescence enable precise cellular and molecular imaging, aiding in early disease detection and monitoring (Abdel-Salamet al., 2020). QDs are utilised in multiplexed imaging, in which numerous biological targets are visualized simultaneously, enhancing diagnostic accuracy (Díaz‑Gonzálezet al., 2020). Furthermore, QDs are being explored for precise administration of medication. Their surfaces allows for the exact delivery of medicines to sick cells while limiting negative effects when functionalised with particular ligands or antibodies (Díez-Pascual, 2022). This targeted approach promises significant advancements in therapy for illnesses such as cancer, showcasing that vast potential that of quantum dots in improving healthcare outcomes (Muraret al., 2022).

Quantum Dots (QDs) have transformative uses for imaging and drug delivery, leveraging its distinct visual characteristics and functional versatility (Biswaset al., 2024). In imaging, QDs are used extensively for their exceptional brightness and photostability, which surpass those of traditional fluorescent dyes Table 1 (Liet al., 2022). Their size-tuneable fluorescence allows for multicolour visualising, allowing scientists to label and track multiple biochemical molecules simultaneously (Tessitoreet al., 2021). This capability is especially beneficial in cellular and molecular visualising, where QDs provide high-resolution and long-term imaging of cellular processes, aiding in the study of disease mechanisms and early diagnosis (Guoet al., 2021). For example, QDs conjugated Using targeted compounds, cancer cells can be selectively bound, facilitating the particular visualization that of tumours and metastases (Jinet al., 2020). This specificity improves the accuracy of diagnostic imaging and the effectiveness of treatments (Pellicoet al., 2021).

In drug delivery, QDs offer precise targeting capabilities. Their surfaces ligands, antibodies, or peptides that bind can be used to functionalise specifically as well target cells, such as cancer cells (Dhaset al., 2022). This targeted delivery system ensures that therapeutic agents are delivered directly to ill cells, reducing adverse effects across the body, and enhancing treatment efficacy (Majumder and Minko, 2021). Additionally, QDs enable real-time medication tracking distribution additionally release inside the body, providing valuable feedback on the therapeutic process and enhancing personalized medicine approaches (Chenet al., 2012). The integration of QDs in imaging and drug delivery exemplifies their significant potential in advancing healthcare technologies (Alharbiet al., 2024).

The quantum confinement effect happens when the dimensions of a semiconductor nanoparticle, such as a Quantum Dot (QD), is diminished to a size that is similar to the exciton Bohr radius, usually between 1 and 10 nm (Osypiwet al., 2022). At this nanoscale, In all three spatial dimensions, the motion of electrons and holes is constrained, resulting in discrete energy levels rather than x the unceasing power bands observed while working with large quantities (Erkaboevet al., 2023). This confinement significantly alters both the optical and electrical properties from the content (Williamet al., 2023). A single of that most notable consequences of quantum confinement is the adjustment of the QD’s emission according to size wavelength (Wanget al., 2020). The energy difference between the valence and conduction bands widens as the QD’s size contracts, elevates, causing a change in the emission spectrum towards shorter wavelengths (blue shift) (Haiet al., 2021). On the other hand, larger QDs produce light at longer wavelengths (red shift) Table 2 because they have a smaller energy gap (Parket al., 2020). As such, property allows precise control over the hue of light released by quantum dots simply by adjusting their dimensions. Furthermore, that quantum confinement effect enhances the absorption cross-section of QDs, making them highly efficient at absorbing and emitting light (Chen, 2020). This effect is crucial for applications in optoelectronics, biological imaging, and photonics, where the ability to manipulate light at the nanoscale is essential (Ghobashyet al., 2024). Overall the size-dependent properties imparted by quantum confinement are foundational to the unique functionality among quantum dots in various technological, as well as academic uses (Kagan et al., 2020).

The quantum confinement effect significantly impacts both the optical and electrical characteristics involving Quantum Dots (QDs), distinguishing them from bulk semiconductor materials (Agarwalet al., 2023). One primary impact is the alteration of the energy of the band gap, which consists of the energy differential between the conduction and valence bands. where a single electron-hole pairs (excitons) recombine to emit photons (Lechifflartet al., 2022). As QDs decrease in size, the gap in the band energy rising as a result of stronger containment in quantum, leading to an alteration to blue in their optical emission (shorter wavelengths) (Emaraet al., 2020). Conversely, larger QDs have smaller bandgap energies, resulting in a red shift (longer wavelengths) (Ebeet al., 2022). This size-dependent tunability of the bandgap enables precise control over the emission spectra of QDs, making them highly versatile for applications requiring specific wavelengths of light (Morselliet al., 2021). For example, in optoelectronics, QDs can be tailored to emit desired colours for high-resolution displays and LED technologies (Kimet al., 2024). Their narrow emission spectra and high brightness enhance the colour quality and efficiency of these devices (Zhanget al., 2020).

In electronic applications, the discrete energy levels of QDs lead to distinct electrical characteristics, like size-tuneable charge carrier flexibility as well as enhanced photoconductivity (Masmaliet al., 2023). These characteristics are exploited in photovoltaic cells to improve light absorption and conversion efficiency (Wanget al., 2022). In photodetectors, the tuneable bandgap allows for sensitivity to specific wavelengths, enhancing their performance (Yadavet al., 2022). Overall, the quantum confinement effect endows QDs with highly customizable electronic and optical properties, driving innovations in display technologies, solar cells, sensors, and biomedical imaging (Qureshiet al., 2024).

Large Quantum Dots: These have a smaller bandgap due to less quantum confinement, resulting in the emission of red light, which has longer wavelengths (Sadhuet al., 2022).

Medium Quantum Dots: These emit green light, with intermediate wavelengths, due to moderate quantum confinement (Chenet al., 2020).

Small Quantum Dots: These exhibit strong quantum confinement, leading to a larger bandgap and the emission of blue light, which has shorter wavelengths (Mohamedet al., 2021).

Quantum dots are known for their high brightness and photostability, which make them superior to traditional fluorescent dyes. Their high quantum yield ensures that a respectable percentage of photons that are absorbed are re- released as fluorescence, resulting in intense brightness (Chenget al., 2023). Additionally, QDs exhibit exceptional resistance to photobleaching, maintaining their luminescence for prolonged periods of time exposed to light. That, makes them ideal for extended-term imaging uses (Yanget al., 2020).

The quantum dots possess wide-ranging absorption spectra, allowing them to absorb an wide spectrum of wavelengths (Liuet al., 2020). This combination of Spectra with wide absorption and narrow emission enhances their utility in making them versatile for excitation by various light sources (Luptonet al., 2021). Conversely, they have narrow, symmetric emission spectra, which lead to sharp and well-defined fluorescence peaks. multiplexed imaging and allows for the several targets are detected simultaneously with little spectral overlap Table 3 (Becerril-Castroet al., 2022).

Quantum Dots (QDs) are highly effective in cellular and molecular imaging because of their remarkable photostability, brightness, additionally size-tunable fluorescence (Kortelet al., 2020). In cellular imaging, QDs have the potential to conjugated Using biomolecules such as nucleic acids, peptides, or antibodies, allowing specific targeting of cellular structures and proteins (Huet al., 2020). This specificity facilitates detailed visualization of cellular processes, interactions, and dynamics at the molecular level. As an illustration, QDs useful for labelling and track individual compounds, enabling real-time observation from biological mechanisms like signal transduction for example, gene expression, and protein trafficking (Bludauet al., 2020). Their strong quantum yield and deterrent to photobleaching make QDs ideal in light of prolonged imaging sessions, surpassing the limitations of conventional fluorescent dyes (Xiaoet al., 2021).

In vivo imaging with QDs offers significant advantages for studying complex biological systems in living organisms (Afshariet al., 2022). QDs able to be designed to target certain tissues instead disease sites, such as tumors, by conjugating them with targeting ligands or antibodies (Abdellatifet al., 2022). Their tunable emission wavelengths allow for imaging using multiplexing, wherein several QDs of various diameters can be employed simultaneously to track various biological targets within the same organism (Ansariet al., 2021). This capability is particularly useful for monitoring disease progression, therapeutic response, and biodistribution of drugs in real-time (Dasguptaet al., 2020). Additionally, the high photostability and brightness of QDs enable deep tissue imaging with minimal signal loss, providing clear and detailed images of internal structures (Pandeyet al., 2020). These properties make QDs invaluable tools in preclinical research and potentially in clinical diagnostics, improving improving comprehension of the mechanisms underlying disease and supporting the creation of targeted treatments (Pantet al., 2021).

Quantum Dots (QDs) significantly enhance cancer detection and visualising because of their exceptional optical characteristics and capacity to target specific cancer biomarkers (Badıllıet al., 2020). By conjugating QDs loaded with peptides, antibodies, or other ligands that are attached to tumor-specific antigenics, researchers can achieve highly targeted imaging of cancer cells (Todaroet al., 2023). This specificity allows for the precise localization of tumors, even at early stages, providing crucial information for diagnosis and treatment planning (Caoet al., 2021). QDs’ exceptional brightness and photostability enable prolonged as well detailed visualisation sessions, facilitating real-time monitoring of tumor growth, metastasis, and response to therapies (Royet al., 2023). Additionally, QDs’ narrow emission spectra and multiplexing capabilities allow simultaneous visualization of multiple cancer markers, offering a comprehensive understanding of tumor heterogeneity and aiding in the development of personalized treatment strategies (Jiaet al., 2024).

Quantum dots are also highly effective in pathogen detection, offering rapid, sensitive, and specific diagnostic capabilities (Looet al., 2022). By conjugating QDs with antibodies or nucleic acid probes that specifically bind to pathogenic bacteria, viruses, or other microorganisms, they in fact suitable for detecting same infections in different samples, such as blood, saliva, or environmental swabs (Shenet al., 2021). The strong and stable fluorescence signal of QDs enables the identification of even minimal amounts of pathogens, improving that sensitivity that of diagnostic assays (Wanget al., 2021). Multiplexing with different QDs enables the rapid identification of several infections in one test at the same time, expediting the diagnostic procedure. and providing comprehensive information about infections(Syedet al., 2024). These advantages make QDs a powerful tool to increase precision and efficiency that of pathogen recognition in clinical diagnostics additionally public health observation (Mousaviet al., 2022).

Functionalizing the surface between Quantum Dots (QDs) with biomolecules is crucial due to their application within targeted drug delivery (Alshamrani, 2022). This process involves attaching biological molecules, for example peptides, tiny compounds, proteins, or nucleic acids, to that surface of QDs (Dos et al., 2020). These modifications enhance how long-lasting and biocompatible QDs are in biological circumstances, reducing potential toxicity (Huanget al., 2024). Additionally, surface biomolecules can be tailored to interact specifically with cellular receptors or other biological targets, assisting in the precise transportation of medicinal substances (Mitchellet al., 2021). For example, Polyethylene Glycol (PEG) can be used to coat QDs, improving the duration of their circulatory circulation and preventing immune recognition (Gidwaniet al., 2021). Such modifications enable QDs to effectively navigate the complex biological milieu and reach their intended targets (Liuet al., 2024).

To achieve targeted drug delivery, QDs are often combined with targeting antigen-recognizing ligands or antibodies and bind to particular surface of the cell markers (Kargozaret al., 2020). These markers are typically overexpressed on diseased cells, such as cancer cells, allowing for selective targeting (Hanet al., 2020). For instance, QDs can be functionalized with antibodies against HER2, a receptor overexpressed in certain breast cancers, ensuring that the QDs specifically home in on cancerous cells while sparing healthy tissues (Hesemanset al., 2022). Ligands such as folic acid, which targets the folate receptor commonly overexpressed in various tumors, can also be used. This targeted approach maximizes the drug’s effectiveness in treating a condition QDs, reduces impacts that are not intended, and minimizes hazardous systems throughout the body (Fatimaet al., 2022). By ensuring that drugs are delivered directly to diseased cells, this method enhances that accuracy and efficacy of the therapies, paving that way for advanced therapeutic strategies in personalized medicine (Lattanziet al., 2021).

Passive targeting leverages the phenomenon known as the Enhanced Permeability and Retention (EPR) effect where minuscule particles, like Quantum Dots (QDs), preferentially form in tumour tissues as a result of the distinct vascular structure of these tissues (Zhanget al., 2022). Tumours typically have leaky vasculature with large endothelial gaps, allowing nanoparticles to penetrate and remain more readily than in normal tissues in the interstitium of the tumour (Niet al., 2022). Additionally, tumors often have poor lymphatic drainage, which further aids in the retention of these nanoparticles (Shindeet al., 2022). By exploiting the EPR effect, drug-loaded QDs can passively accumulate in tumor sites, providing an elevated local dosage of the medicinal substance directly within the tumor environment (Sahuet al., 2022). This passive targeting enhances the maximising the therapeutic outcome while reducing systemic adverse effects (Zhiet al., 2020).

Active targeting is the process of functionalising QDs using particular ligands or antibodies that attach to target cells, including cancer cells, that have their receptors overexpressed (da et al., 2021). This receptor-mediated targeting ensures that QDs selectively bind to and are internalized by the target cells, delivering their therapeutic payload directly to the diseased site (Gopalanet al., 2020). For example, QDs conjugated potentially target cancer cells that overexpress folate receptors by using folic acid, or antibodies against the HER2 receptor can direct QDs to HER2-positive breast cancer cells (Rajaniet al., 2020). This precise targeting enhances the therapeutic efficacy by increasing the accumulation of the drug around the location of the illness and reducing off-target effects unintended consequences (Ouyanget al., 2022). Active targeting Moreover, improves medication administration specificity however, additionally allows for the possible application of lower drug doses, lowering the possibility of negative consequences and enhancing patient outcomes (Rahimet al., 2021).

Quantum Dots (QDs) offer significant advantages in drug delivery due to their enhanced targeting precision (Wanget al., 2020). By functionalizing QDs Using particular ligands or antibodies, they are able to selectively attach to the intended cells, such as cancer cells, overexpressing certain receptors (Shukla et al., 2023). This precision targeting ensures that therapeutic agents are sent out directly to the diseased site, minimizing damage to healthy tissues and reducing systemic side effects (Manzariet al., 2021). Because QDs are tiny, they can penetrate tissues and cellular barriers effectively, enhancing the delivery of drugs to intracellular targets (Veselovet al., 2022). The elevated ratio of QDs’ surface area to volume also permits the attachment that of multiple targeting molecules and therapeutic agents, improving targeting accuracy and therapeutic payload delivery (Tanet al., 2020). This precise targeting can lead to improved treatment efficacy, particularly in complex diseases like cancer, where targeting specific cell populations is crucial Table 4 (Bejaranoet al., 2021).

The capacity of QDs to provide real-time tracking and monitoring of medication distribution is another significant benefit of using them in drug delivery within the body (Sarkaret al., 2024). The intrinsic fluorescence properties of QDs allow them to be visualized using various imaging techniques, providing detailed insights into their biodistribution and pharmacokinetics (Aladesuyiet al., 2022). This real-time tracking capability allows researchers and clinicians to monitor the delivery and release of drugs making certain that the medicinal ingredients are present at the intended location reach their intended destination and remain there for the desired duration (Rana et al., 2023). It also helps to make the adjustment that of Various therapy regimens determined on the distribution that was seen patterns, optimizing therapeutic outcomes (Hakamiet al., 2024). Additionally, this capability can be used to track the clearance and potential accumulation of QDs, addressing safety and toxicity concerns (Wanget al., 2021). The ability to keep track of medications delivery in the moment thus enhances that precision and effectiveness of treatments, enabling the development of more customised and adaptive therapeutic techniques (Balogunet al., 2023).

Quantum Dots (QDs) are making strides towards clinical translation and medical applications, Since they have special optical qualities and developments in biocompatibility (Tripathiet al., 2023). Recent years have seen QDs with enhanced safety characteristics are being developed, including those with non-toxic cores and biocompatible coatings (Reddyet al., 2024). These innovations have enabled the initiation of preclinical studies and early-phase clinical trials (Choet al., 2023). For instance, QDs are being tested for their efficacy in imaging-guided surgery, where their bright fluorescence helps surgeons visualize tumor margins more accurately (Liet al., 2021). While regulatory approval remains a challenge, the growing body of safety and efficacy data is paving the way for more extensive clinical trials Tables 5 and 6 (Galderisiet al., 2022).

Quantum dots have the capacity to completely transform customised treatment by making more exact diagnostics and focused treatments (Guoet al., 2024). Their ability to provide detailed molecular and cellular imaging can help identify specific biomarkers associated with individual patients’ diseases, facilitating tailored treatment plans (Weberet al., 2020). For example, QD-based imaging can distinguish between different types of tumors or detect subtle changes in disease states, enabling more precise diagnoses and monitoring that of treatment reactions (Aliet al., 2023). By targeting particular cells or tissues with QDs, medication delivery can be optimised to reduce side effects and enhance therapeutic effectiveness (Yetisginet al., 2020). This precision medicine approach guarantees that patients are given therapies that are most productive for their unique genetic and molecular profiles, ultimately leading to better outcomes and more efficient healthcare (Dlaminiet al., 2022). The incorporating QDs into medical procedures could thus significantly enhance the customization of patient care (Daiet al., 2022).

Recent advancements in Quantum Dot (QD) synthesis and functionalization have significantly enhanced their potential for biomedical applications (Thangaduraiet al., 2022). Innovations in synthesis techniques have focused on creating QDs with precise size, shape, and composition control, resulting in uniform and highly tuneable optical properties (Yanget al., 2022). Methods such as hot-injection, colloidal synthesis, and chemical vapor deposition have been refined to create QDs that are stable and have a high quantum yield (Meng, 2023). These improved synthesis protocols have also led to the progression of nontoxic heavy metal-free QDs, including carbon, silicon, and perovskite QDs, which address safety concerns associated with traditional cadmium-based QDS.

Functionalization advancements have focused on improving QDs’ capacity to target and be biocompatible (Singhet al., 2024). Surface alteration techniques, including ligand exchange, encapsulation with biocompatible polymers (e.g., polyethylene glycol), and the attachment of biomolecules (e.g., antibodies, peptides, and aptamers), have been optimized to improve QD solubility, stability, and specificity in biological environments (Eroğluet al., 2020). These functionalized QDs are capable of binding to specific target cells or tissues, facilitating exact imaging additionally targeted drug delivery (Zhanget al., 2020).

Quantum Dots (QDs), semiconductor nanoparticles, exhibit unique optical properties such as size-tuneable emission wavelengths, high brightness, and photostability due to quantum confinement. These properties allow QDs to emit light in various colors depending on their size, with narrow emission spectra and broad absorption, making them ideal for high-resolution, multicolour imaging. Their application in biological and medical imaging is significant, providing detailed visualization at cellular and chemical levels. In drug delivery, QDs can be functionalized with biomolecules for precise targeting and effective therapeutic administration, reducing side effects and improving outcomes. QDs enable prolonged, high-accuracy observation of biological processes, enhancing diagnostic precision. Their multicolour imaging capability allows simultaneous detection of multiple targets, offering insights into complex interactions. Additionally, real-time tracking of drug distribution enhances therapeutic efficacy. Innovations in QD technology include developing non-toxic QDs from materials like carbon or silicon, multifunctional QDs for imaging and therapy (theranostics), improved targeting mechanisms, integration with advanced imaging techniques, and personalized medicine approaches. These advancements position QDs as a critical tool in enhancing diagnostic and therapeutic precision, particularly in personalized medicine.

The authors are extremely thankful Raghavendra Institute of Pharmaceutical Education and Research for their extreme support and knowledge.