Quantum Dots For Imaging and Drug Delivery in Cancer Therapy

A collection of illnesses known as cancer is distinguished by the quick proliferation of aberrant cells throughout the body. The majority of cancer cases are caused by mutations or alterations in the expression of tumor suppressor genes, DNA repair genes, and proto-oncogenes. In addition to signs of an unhealthy lifestyle (tobacco use, bad diet), genetic (hormones, mutations, immune conditions) and environmental (radiation, chemicals, pollutants) variables are responsible for the majority of cancers. In addition, aging raises the risk of developing cancer considerably [2]. The use of tumor-specific antibody conjugates for active tumor targeting in novel anticancer therapies has attracted a lot of attention in the fields of oncology, pharmacology, and nanomedicine. This method will enable to enhance therapeutic effectiveness and lower systemic toxicity [3]. Nanotechnology has revolutionized the pharmaceutical and medical sectors with its revolutionary potential, paving the way for early diagnosis and medication delivery. Quantum dots (QDs), nanoscale zero-dimensional crystals that have a wide range of optical, spectral, magnetic, and electrochemical characteristics, are at the forefront of this nanotechnological revolution. QDs have received a lot of attention among the numerous nanomaterials as a crucial instrument in bioimaging and cancer drug delivery. [4] Ekimov and Onushenko first described quantum dots (QDs), sometimes referred to as nanoscale semiconductor crystals, in a glass matrix in 1981, and the first application for biological imaging was published in 1998. The field of QDs has been steadily expanding ever since, with applications in areas such as photodetectors, biomedical imaging, computing, light-emitting diode (LED) manufacturing, photovoltaic devices, solar cells, and more. [5] QDs have exceptional optical characteristics that make them promising candidates for use as luminescent nano-probes and carriers in biological applications. Drug QD nano-carriers can be loaded with drugs by dissolving, dispersing, adsorbing, and coupling, among other methods. The carriers next alter the physical and chemical properties of drugs (such as saturation solubility, dissolution rate, crystal form, particle surface hydrophobicity and hydrophilicity), as well as their biological behavior and physical response, thereby affecting how drugs are absorbed, distributed, metabolized, and excreted [6].

Structure of QDs:

Quantum dots are composed of tiny metal particles that are around a thousand times smaller than a hair. These particles are shaped into different shapes and covered in various biomaterials. Quantum dots fluoresce in UV light, and their size determines the shade they produce. For example, QD (2 nm) had red fluorescence, whereas QD (2 nm) fluoresced clearly in green. The majority of fluorescent quantum dots are made of chemicals ranging from group II to VI and III to V, such as Cd, Hg, Se, Ag, Ln, P, Pb, Te, and Zn. The frequency that quantum dots produce becomes more constrained as their size decreases. They have a defined discharge frequency, so their spectra do not show a variety of fluorescence radiations [7]. The structure of quantum dots includes a core, shell, and sometimes a surface coating, which gives them a high degree of stability in photo and chemical behaviors, surface activation, and photo luminescence quantum yield [2].

Fig.1: Basic Structure of QDs With Shell, Core & Ligand.

Fig.2: Formation of Quantum Dot Particle.

Fig.3: Quantum Dots Synthesis Flow Chart.

Figure 4: A schematic representation of QD administered into a tumor-bearing mouse for in vivo tumor research is shown.

CHALLENGES

The toxicity of QDs remains the biggest impediment to clinical translation, despite the possible immense social advantages they provide for human illness. The biochemical processes underlying cytotoxicity are now being understood. The toxicity of QDs has been linked to their charge, size, concentration, and stability, as well as the bioactivity of their outer coating [9].

Despite the enormous potential of QDs in biomedical imaging and detection, toxicological and pharmacological problems, primarily related to heavy metals and colloidal instability, impede progress toward cancer diagnosis and treatment as well as other illnesses. Nanotoxicology The development of these applications in vitro may not be hampered by these issues, but they present significant obstacles to their use in vivo for human cancer imaging [12].

(Cd Se) ZnS is the most prevalent QD makeup. It has a core of cadmium and selenium, both of which are well known to be harmful [9].

Although CdSe and CdTe semiconductor materials have been widely utilized as the core of QDs, they have been shown to exhibit cytotoxicity at low concentrations. As a result, silicon or AgInS2 core-based novel QDs that exclude Cd, Se, and Te elements have already been created, and these QDs have been shown to have minimal toxicity [11].

FUTURE PROSPECTS

Scientists in the domains of chemistry, biology, medical engineering, and pharmaceutical sciences have come together in a shared effort to establish QDs as technological advancements with features that could significantly advance in vivo and in vitro imaging as well as achieve notable advances in the field of nanomedicine research [10].

The flexibility of QDs allows for novel approaches to treating cancer. Recent research has shown that black phosphorus material functions as a "nanoknife," allowing for the exact tumor ablation described in the article. BPQDs are being investigated for use in chemotherapeutic medication delivery and may potentially be used as nanoknives as well as nanocarriers [4].

A variety of efforts should be made to create unique QDs based on their composition, sizes, surface coatings, and valences in order to reduce toxicity and optimize detection performance. Consider, however, challenges such as shell coating degradation brought about by QD [7].

In vivo theranostics [11], an approach that likely allows for the simultaneous diagnosis and treatment of stem cells in vivo, is made possible by the development of hybrid materials between QDs and other functional molecules during the evolution of QDs.

Immunomodulatory capabilities may be included in future QD-based treatments. QDs that are functionalized with immune checkpoint inhibitors or stimulatory molecules may help the immune system identify and destroy cancer cells. For a full cancer treatment, such approaches might combine with chemotherapy and radiation [4].

CONCLUSION

The use of nanoparticles in the battle against cancer has been the subject of considerable study. Because nanoparticles have a number of traits necessary to address the drawbacks of standard cancer therapy methods, they may be used as a basis for early diagnosis and treatment. The most recent nanoparticles to show distinctive characteristics that might revolutionize cancer diagnosis and treatment are quantum dots. The characteristics of these features include their tiny tunable size, consistent photoluminescence, high surface-to-volume ratio, and possibility for biocompatibility. QDs have been widely used for tumor imaging in vitro and in vivo, and they have also been combined with therapeutic medicines for targeted drug delivery in vivo. Early tumor identification and diagnosis, bioimaging, targeted gene-drug delivery, phototherapy, and medication delivery are the main applications of QDs in cancer therapy. Due to their excellent biocompatibility, low cytotoxicity, and high capacity for cell uptake, QDs are also the preferred method of drug administration. There is no doubt that QDs have tremendous promise for use in bio-imaging, sensors, drug delivery, and other fields. To realize the true potential of QDs in clinical practice, a number of challenges must yet be overcome, including overall toxicity, body clearance, the scalability of the synthesis procedure, environmental effects, manufacturing costs, and other factors. Theranostic platforms are always being created by combining QDs with additional kinds of nanoparticles and/or biologically active compounds.

REFERENCES

1. National Cancer Institute. (2015). What is cancer? U.S. Department of Health and Human Services, National Institutes of Health. (https://www.cancer.gov/about-cancer/understanding/what-is-cancer).
2. Hamidu, A., Pitt, W. G., & Husseini, G. A. (2023). Recent Breakthroughs in Using Quantum Dots for Cancer Imaging and Drug Delivery Purposes. Nanomaterials (Basel, Switzerland), 13(18), 2566. https://doi.org/10.3390/nano13182566
3. Tada, H., Higuchi, H., Wanatabe, T. M., & Ohuchi, N. (2007). In vivo real-time tracking of single quantum dots conjugated with monoclonal anti-HER2 antibody in tumors of mice. Cancer research, 67(3), 1138–1144. https://doi.org/10.1158/0008-5472.CAN-06-1185
4. Pareek, A., Kumar, D., Pareek, A., & Gupta, M. M. (2025). Advancing Cancer Therapy with Quantum Dots and Other Nanostructures: A Review of Drug Delivery Innovations, Applications, and Challenges. Cancers, 17(5), 878. https://doi.org/10.3390/cancers17050878
5. Matea, C. T., Mocan, T., Tabaran, F., Pop, T., Mosteanu, O., Puia, C., Iancu, C., & Mocan, L. (2017). Quantum dots in imaging, drug delivery and sensor applications. International journal of nanomedicine, 12, 5421–5431. https://doi.org/10.2147/IJN.S138624
6. Zhao, M. X., & Zhu, B. J. (2016). The Research and Applications of Quantum Dots as Nano-Carriers for Targeted Drug Delivery and Cancer Therapy. Nanoscale research letters, 11(1), 207. https://doi.org/10.1186/s11671-016-1394-9
7. Devi, S., Kumar, M., Tiwari, A., Tiwari, V., Kaushik, D., Verma, R., Bhatt, S., Sahoo, B. M., Bhattacharya, T., Alshehri, S., Ghoneim, M. M., Babalghith, A. O., & Batiha, G. E.-S. (2022). Quantum dots: An emerging approach for cancer therapy. Frontiers in Materials, 8, 798440. https://doi.org/10.3389/fmats.2021.798440
8. Iannazzo, D., Celesti, C., & Espro, C. (2021). Recent Advances on Graphene Quantum Dots as Multifunctional Nanoplatforms for Cancer Treatment. Biotechnology journal, 16(2), e1900422. https://doi.org/10.1002/biot.201900422
9. Luo, G., Long, J., Zhang, B., Liu, C., Ji, S., Xu, J., Yu, X., & Ni, Q. (2012). Quantum dots in cancer therapy. Expert opinion on drug delivery, 9(1), 47–58. https://doi.org/10.1517/17425247.2012.638624
10. Cheki, M., Moslehi, M., & Assadi, M. (2013). Marvelous applications of quantum dots. European review for medical and pharmacological sciences, 17(9), 1141–1148.
11. Onoshima, D., Yukawa, H., & Baba, Y. (2015). Multifunctional quantum dots-based cancer diagnostics and stem cell therapeutics for regenerative medicine. Advanced drug delivery reviews, 95, 2–14. https://doi.org/10.1016/j.addr.2015.08.004
12. Fang, M., Peng, C. W., Pang, D. W., & Li, Y. (2012). Quantum dots for cancer research: current status, remaining issues, and future perspectives. Cancer biology & medicine, 9(3), 151–163. https://doi.org/10.7497/j.issn.2095-3941.2012.03.001
13. Iannazzo, D., Pistone, A., Celesti, C., Triolo, C., Patané, S., Giofré, S. V., Romeo, R., Ziccarelli, I., Mancuso, R., Gabriele, B., Visalli, G., Facciolà, A., & Di Pietro, A. (2019). A Smart Nanovector for Cancer Targeted Drug Delivery Based on Graphene Quantum Dots. Nanomaterials (Basel, Switzerland), 9(2), 282. https://doi.org/10.3390/nano9020282
14. Pardo, J., Peng, Z., & Leblanc, R. M. (2018). Cancer Targeting and Drug Delivery Using Carbon-Based Quantum Dots and Nanotubes. Molecules (Basel, Switzerland), 23(2), 378. https://doi.org/10.3390/molecules23020378
15. Zhang, H., Yee, D., & Wang, C. (2008). Quantum dots for cancer diagnosis and therapy: biological and clinical perspectives. Nanomedicine (London, England), 3(1), 83–91. https://doi.org/10.2217/17435889.3.1.83
16. Chen, L. L., Zhao, L., Wang, Z. G., Liu, S. L., & Pang, D. W. (2022). Near-Infrared-II Quantum Dots for In Vivo Imaging and Cancer Therapy. Small (Weinheim an der Bergstrasse, Germany), 18(8), e2104567. https://doi.org/10.1002/smll.202104567
17. Gao, X., Cui, Y., Levenson, R. M., Chung, L. W., & Nie, S. (2004). In vivo cancer targeting and imaging with semiconductor quantum dots. Nature biotechnology, 22(8), 969–976. https://doi.org/10.1038/nbt994
18. Misra, R. D. (2008). Quantum Dots for Tumor-Targeted Drug Delivery and Cell Imaging. Nanomedicine, 3(3), 271–274. https://doi.org/10.2217/17435889.3.3.271
19. Ding, H., Zhang, F., Zhao, C., Lv, Y., Ma, G., Wei, W., & Tian, Z. (2017). Beyond a Carrier: Graphene Quantum Dots as a Probe for Programmatically Monitoring Anti-Cancer Drug Delivery, Release, and Response. ACS applied materials & interfaces, 9(33), 27396–27401. https://doi.org/10.1021/acsami.7b08824
20. Zeng, Q., Shao, D., He, X., Ren, Z., Ji, W., Shan, C., Qu, S., Li, J., Chen, L., & Li, Q. (2016). Carbon dots as a trackable drug delivery carrier for localized cancer therapy in vivo. Journal of Materials Chemistry B, 4(30), 5119-5126. https://doi.org/10.1039/C6TB01259K
21. Thakor, A. S., & Gambhir, S. S. (2013). Nanooncology: the future of cancer diagnosis and therapy. CA: a cancer journal for clinicians, 63(6), 395–418. https://doi.org/10.3322/caac.21199
22. Luque-Michel, E., Imbuluzqueta, E., Sebastián, V., & Blanco-Prieto, M. J. (2017). Clinical advances of nanocarrier-based cancer therapy and diagnostics. Expert opinion on drug delivery, 14(1), 75–92. https://doi.org/10.1080/17425247.2016.1205585
23. Li, J., Liu, F., Gupta, S., & Li, C. (2016). Interventional Nanotheranostics of Pancreatic Ductal Adenocarcinoma. Theranostics, 6(9), 1393–1402. https://doi.org/10.7150/thno.15122
24. Din, F. U., Aman, W., Ullah, I., Qureshi, O. S., Mustapha, O., Shafique, S., & Zeb, A. (2017). Effective use of nanocarriers as drug delivery systems for the treatment of selected tumors. International journal of nanomedicine, 12, 7291–7309. https://doi.org/10.2147/IJN.S146315
25. Cheng, C., Li, S., Thomas, A., Kotov, N. A., & Haag, R. (2017). Functional Graphene Nanomaterials Based Architectures: Bio interactions, Fabrications, and Emerging Biological Applications. Chemical reviews, 117(3), 1826–1914. https://doi.org/10.1021/acs.chemrev.6b00520
26. Gabriele, B., Mancuso, R., Salerno, G., & Veltri, L. (2005). Sequential homobimetallic catalysis: an unprecedented tandem Pd (0)-catalysed deprotection – Pd (II)-catalysed heterocyclisation reaction leading to benzofurans. Chemical communications (Cambridge, England), (2), 271–273. https://doi.org/10.1039/b413240h
27. Zaharie-Butucel, D., Potara, M., Craciun, A. M., Boukherroub, R., Szunerits, S., & Astilean, S. (2017). Revealing the structure and functionality of graphene oxide and reduced graphene oxide/pyrene carboxylic acid interfaces by correlative spectral and imaging analysis. Physical chemistry chemical physics: PCCP, 19(24), 16038–16046. https://doi.org/10.1039/c7cp02443f
28. Kano, M. R., Bae, Y., Iwata, C., Morishita, Y., Yashiro, M., Oka, M., Fujii, T., Komuro, A., Kiyono, K., Kaminishi, M., Hirakawa, K., Ouchi, Y., Nishiyama, N., Kataoka, K., & Miyazono, K. (2007). Improvement of cancer-targeting therapy, using nanocarriers for intractable solid tumors by inhibition of TGF-beta signalling. Proceedings of the National Academy of Sciences of the United States of America, 104(9), 3460–3465. https://doi.org/10.1073/pnas.0611660104
29. Dadwal, A., Baldi, A., & Kumar Narang, R. (2018). Nanoparticles as carriers for drug delivery in cancer. Artificial cells, nanomedicine, and biotechnology, 46(sup2), 295–305. https://doi.org/10.1080/21691401.2018.1457039
30. Bentolila, L. A., Ebenstein, Y., & Weiss, S. (2009). Quantum dots for in vivo small-animal imaging. Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 50(4), 493–496. https://doi.org/10.2967/jnumed.108.053561
31. Liang, Z., Khawar, M. B., Liang, J., & Sun, H. (2021). Bio-Conjugated Quantum Dots for Cancer Research: Detection and Imaging. Frontiers in oncology, 11, 749970. https://doi.org/10.3389/fonc.2021.749970
32. Ferlay, J., Colombet, M., Soerjomataram, I., Parkin, D. M., Piñeros, M., Znaor, A., & Bray, F. (2021). Cancer statistics for the year 2020: An overview. International journal of cancer, 10.1002/ijc.33588. Advance online publication. https://doi.org/10.1002/ijc.33588
33. Wu, S., Zhu, W., Thompson, P., & Hannun, Y. A. (2018). Evaluating intrinsic and non-intrinsic cancer risk factors. Nature communications, 9(1), 3490. https://doi.org/10.1038/s41467-018-05467-z
34. Ferrari M. (2005). Cancer nanotechnology: opportunities and challenges. Nature reviews. Cancer, 5(3), 161–171. https://doi.org/10.1038/nrc1566
35. Duncan R. (2006). Polymer conjugates as anticancer nanomedicines. Nature reviews. Cancer, 6(9), 688–701. https://doi.org/10.1038/nrc1958
36. Burz, C., Pop, V. V., Buiga, R., Daniel, S., Samasca, G., Aldea, C., & Lupan, I. (2018). Circulating tumor cells in clinical research and monitoring patients with colorectal cancer. Oncotarget, 9(36), 24561–24571. https://doi.org/10.18632/oncotarget.25337
37. Shamsi, J., Dang, Z., Bianchini, P., Canale, C., Stasio, F. D., Brescia, R., Prato, M., & Manna, L. (2016). Colloidal Synthesis of Quantum Confined Single Crystal CsPbBr3 Nanosheets with Lateral Size Control up to the Micrometer Range. Journal of the American Chemical Society, 138(23), 7240–7243. https://doi.org/10.1021/jacs.6b03166
38. Karanikolos, G. N., Alexandridis, P., Itskos, G., Petrou, A., & Mountziaris, T. J. (2004). Synthesis and size control of luminescent ZnSe nanocrystals by a microemulsion-gas contacting technique. Langmuir : the ACS journal of surfaces and colloids, 20(3), 550–553. https://doi.org/10.1021/la035397+
39. K Tiwari, P., Sahu, M., Kumar, G., & Ashourian, M. (2021). Pivotal Role of Quantum Dots in the Advancement of Healthcare Research. Computational intelligence and neuroscience, 2021, 2096208. https://doi.org/10.1155/2021/2096208
40. Lees, E. E., Nguyen, T. L., Clayton, A. H., Muir, B. W., & Mulvaney, P. (2009). The preparation of colloidally stable, water-soluble, biocompatible, semiconductor nanocrystals with a small hydrodynamic diameter. ACS nano, 3(5), 1121–1128. https://doi.org/10.1021/nn900144n
41. Heyne, B., Arlt, K., Geßner, A., Richter, A. F., Döblinger, M., Feldmann, J., Taubert, A., & Wedel, A. (2020). Mixed Mercaptocarboxylic Acid Shells Provide Stable Dispersions of InPZnS/ZnSe/ZnS Multishell Quantum Dots in Aqueous Media. Nanomaterials (Basel, Switzerland), 10(9), 1858. https://doi.org/10.3390/nano10091858
42. Speranskaya, E. S., Beloglazova, N. V., Lenain, P., De Saeger, S., Wang, Z., Zhang, S., Hens, Z., Knopp, D., Niessner, R., Potapkin, D. V., & Goryacheva, I. Y. (2014). Polymer-coated fluorescent CdSe-based quantum dots for application in immunoassay. Biosensors & bioelectronics, 53, 225–231. https://doi.org/10.1016/j.bios.2013.09.045
43. Carrillo-Carrion, C., & Parak, W. J. (2016). Design of pyridyl-modified amphiphilic polymeric ligands: Towards better passivation of water-soluble colloidal quantum dots for improved optical performance. Journal of colloid and interface science, 478, 88–96. https://doi.org/10.1016/j.jcis.2016.05.058
44. Khan, M. M. R., Mitra, T., & Sahoo, D. (2020). Metal oxide QD based ultrasensitive microsphere fluorescent sensor for copper, chromium and iron ions in water. RSC advances, 10(16), 9512–9524. https://doi.org/10.1039/c9ra09985a
45. Smith, A. M., Duan, H., Mohs, A. M., & Nie, S. (2008). Bioconjugated quantum dots for in vivo molecular and cellular imaging. Advanced drug delivery reviews, 60(11), 1226–1240. https://doi.org/10.1016/j.addr.2008.03.015