Quantum dots

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Quantum dots in pharmacy

Quantum dots (QDs) is a special kind of semiconducting nano materials consisting of a metalic semiconductor core such as CdSe which is most commonly coated by a shell (e.g., ZnS) to improve optical behaviour(11). Their unique properties evolves from their physical size, which ranges from 10-100 A in radius. Due to their some unique features like bright fluorescence, narrow emission, broad UV excitation and high photostability QDs have been utilised in pharmaceutical field of novel research including in-vitro bioimaging for monitoring or tracking of intracellular mechanism of different drugs for longer duration. Quantum-dots have a huge impact on drug development and pharmaceutical research.

Fig 3: Colloidal nanoparticle(Quantum dots) of lead sulfide (selenide)(13)

The following are the some important uses of quanttm dots.(12-13)

1.Quantum-dots is explored as a new divice in the area of diagnosis of diseases including different medical areas like diagnostic tools (MRI),

2. In vitro and in vivo detection of different kind of diseases and analysis of biomolecules can be performed by quantum dots technology.

3. Quantum dots (QDs) have also been investigated as fluorescent labels for immunoassays . QDs are semiconductor nanocrystals whose diameter varies from 2 to 10 nm; their fluorescence emission peak strongly depends on their size as well as their composition. Water-soluble QDs have a surface coating enriched with carboxyl or amine groups, thus facilitating their conjugation with antibodies Immunoassays.

4. DNA hybridization: The density of DNA probes on the QD surface was controlled to avoid steric hindrance and to

promote rapid hybridization with target DNA molecules.

5. development of non-viral vectors for gene therapy, transport vehicles for DNA, protein, drugs or cells, time graded fluorescence imaging of tissue, labeling of cells and as therapeutic tools for cancer treatment (11-13).

References:

11. Resch-Genger, U.; Grabolle, M.; Cavaliere-Jaricot, S.; Nitschke, R.; Nann, T. Quantum dotsversus organic dyes as fluorescent labels. Nat. Methods 2008, 5, 763-775.

12. Schrock, E.; du Manoir, S.; Veldman, T.; Schoell, B.; Wienberg, J.; Ferguson-Smith, M.; Ning,Y.; Ledbetter, D.; Bar-Am, I.; Soenksen, D.; Garini, Y.; Ried, T. Multicolor spectral karyotypingof human chromosomes. Science 1996, 273, 494-497.

13. http://en.wikipedia.org/wiki/Quantum_dot

About the Author

Anirbandeep Bose's picture

I am Dr. Anirbandeep Bose working as an Asst. Prof in Acharya and Bm Reddy college of Pharmacy ,Bangalore.Before that I worked as postdoctoral fellow in Pharmacy department of University Technology Mara(UiTM),Malaysia.I was awarded the post doctoral fellowship by the Malaysian higher education Ministry. Before that I got awarded PhD in Pharmaceutics from Jadavpur University,Kolkata,India. I worked as production chemist(Tablets and Capsule manufacturing) in BHP(1981)PVT. LTD for more than 2 years. I have more than 30 international publications related this field and attended many international conference.

Comments

Meghana's picture

ITS nice and informative

Prof. J. Vijaya Ratna's picture

Dear Dr. Anirbandeep Bose

Your blog is very interesting. But can we think of using lead sulfide in making Drug delivery systems? Is it not harmful to the body?

Vijaya Ratna

Anirbandeep Bose's picture

Very good question.

The QDs toxicity has been widely discussed over the past few years especially for cadmium and lead-based QDs. It was found that upon encapsulating the QDs with PbS, the toxicity of the PbS QDs is reduced.Lead sulfide is also insoluble and a stable compound in the pH of blood and so it is the less toxic forms of lead.Still due to its toxicity PbS are replaced by ZnS as coating materials
Semiconductor quantum dots (Qdots) are a promising novel technology with its major advantages in the areas of medical diagnostics and therapeutics. Qdots generally consist of a semiconductor core, capping shell, and surface coating. The semiconductor core of Qdots is mainly composed of group II and VI metals (e.g., Cd, Se, Te, Hg) that are known to have toxic properties. Various surface coatings have been shown to stabilize Qdots and thus shield cells from the toxic properties of their core elements.

Dr. Anirbandeep Bose

Assistant Prof.

ACHARYA AND BM REDDY COLLEGE OF PHARMACY

Bangalore

India

Prof. J. Vijaya Ratna's picture

Researchers in the field of drug delivery systems are wary of using materials that have possible toxicity. For example, very small concentrations of formaldehyde are sufficient to give hardening effect to the walls of microcapsules; thus we get very good sustained release. But the unpleasant smell, taste and toxicity also are seen with very low concentrations. So, personally I am not in favour of using formaldehyde in internal drug delivery systems.

If a "compare and contrast" can be made between the presently used (in novel drug delivery systems), natural biodegradable materials like phospholipids and the proposed materials like lead sulphide and zinc sulphide, it will be of great interest to all researchers.

Thank you for starting this interesting topic and for the reply.

Vijaya Ratna

Anirbandeep Bose's picture

I think also there is a great prospect for the researcher to explore the field of quantum dots in drug discovery.

Thanks for your valuable comment.

Dr. Anirbandeep Bose

Assistant Prof.

ACHARYA AND BM REDDY COLLEGE OF PHARMACY

Bangalore

India

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