Quantum Dot-based Bio-conjugates as an Emerging Bioimaging Tool for Cancer Theranostic- A Review.

Cancer is the most widely studied disorder in humans, but proper treatment has not yet been developed for it. Conventional therapies, like chemotherapy, radiation therapy, and surgery, have been employed. Such therapies target not only cancerous cells but also harm normal cells. Conventional therapy does not result in specific targeting and hence leads to severe side effects. The main objective of this study is to explore the QDs. QDs are used as nanocarriers for diagnosis and treatment at the same time. They are based on the principle of theranostic approach. QDs can be conjugated with antibodies via various methods that result in targeted therapy. This results in their dual function as a diagnostic and therapeutic tool. Nanotechnology involving such nanocarriers can increase the specificity and reduce the side effects, leaving the normal cells unaffected. This review pays attention to different methods for synthesising QDs. QDs can be obtained using either organic method and synthetic methods. It was found that QDs synthesised naturally are more feasible than the synthetic process. Top or bottom-up approaches have also emerged for the synthesis of QDs. QDs can be conjugated with an antibody via non-covalent and covalent binding. Covalent binding is much more feasible than any other method. Zero-length coupling plays an important role as EDC (1-Ethyl-3-Ethyl dimethylaminopropyl)carbodiimide is a strong crosslinker and is widely used for conjugating molecules. Antibodies work as surface ligands that lead to antigen- antibody interaction, resulting in site-specific targeting and leaving behind the normal cells unaffected. Cellular uptake of the molecule is done by either passive targeting or active targeting. QDs are tiny nanocrystals that are inorganic in nature and vary in size and range. Based on different sizes, they emit light of specific wavelengths. They have their own luminescent and optical properties that lead to the monitoring, imaging, and transport of the therapeutic moiety to a variety of targets in the body. The surface of the QDs is modified to boost their functioning. They act as a tool for diagnosis, imaging, and delivery of therapeutic moieties. For improved therapeutic effects, nanotechnology leads the cellular uptake of nanoparticles via passive targeting or active targeting. It is a crucial platform that not only leads to imaging and diagnosis but also helps to deliver therapeutic moieties to specific sites. Therefore, this review concludes that there are numerous drawbacks to the current cancer treatment options, which ultimately result in treatment failure. Therefore, nanotechnology that involves such a nanocarrier will serve as a tool for overcoming all limitations of the traditional therapeutic approach. This approach helps in reducing the dose of anticancer agents for effective treatment and hence improving the therapeutic index. QDs can not only diagnose a disease but also deliver drugs to the cancerous site.

Bio-Functional Mesoporous Silica Nanoparticles as Nano-Structured Carriers in Cancer Theranostic Review on Recent Advancements.

BACKGROUND: Cancer is a life-threatening disease worldwide, but proper treatment has not yet been developed. Many therapies are available to treat cancer disorders, like chemotherapy, surgery, hormone therapy, and immunotherapy. Chemotherapy often relies on a combination of harmful, highly toxic platinum-based compounds. Also, there are chances of poor distribution of chemotherapeutic agents and cytotoxic to most cells which leads to damage to other healthy cells, also, there are chances of resistance. OBJECTIVE: The main objective of this study is the development of mesoporous silica nanoparticles. Mesoporous silica nanoparticles are recognized as carriers with high drug loading capacity and significant functionalized surface area for targeted drug delivery. Mesoporous silica nanoparticles have shape, particle size, pore volume, higher surface area, and the possibility of surface modification. Hence results in thermally and chemically stable nanomaterials. For targeted drug delivery, MSN is conjugated with a variety of ligands, including monoclonal antibodies, hyaluronic acid, transferrin, folic acid, etc., that have a particular affinity for the receptors that are overexpressed on the surface of malignant cells, so using this nanocarrier reducing the dose related toxicity of normal cell. METHODS: This review focuses on different methods for synthesizing mesoporous silica nanoparticles. Sol-gel method and modified stobber method were used for the synthesis of this nanoparticle. RESULTS: Successfully synthesized mesoporous silica nanoparticle with particle size around 50-200 nm and drug loading efficiency was found to be around 71%. CONCLUSION: Mesoporous silica nanoparticles are great carriers for intracellular and targeted drug delivery systems.