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Quantum dots, another way of defeating cancer?

Quantum dots, another way of defeating cancer?
« on: 24 July , 2018, 19:21:11 pm »
Hi everyone, how are you doing?

As we have already talked in other posts, nanotechnology is a cross curricular subject which would influence in nowadays society. Moreover, nanotechnology has been thought to be one of the main solutions for the problems that actual medicine has to overcome. In this post I would like to talk about quantum dots, structures that may prevent the formation of tumorous cells and help in the deliverance of drugs.

First of all, what are quantum dots? Quatum Dots(QDs) are groups of atoms forming a crystalline structure concentrated in a single place of the space, they are zero-dimensional structures. As a result, the electrons and "holes" (places where electrons are missing) are trapped and have well-defined energy levels according with the quantum theory, therefore we find a group of atoms that work as a single atom. When we say that they are zero-dimensional is due the dimesions of the QDs, which have a width of a few nanometers.

Quantum Dots have a peculiarity; they are semiconductor structures. QDs have a valence band, where we can find the electrons, and a conduction band, where there are none electrons. The electrical conductivity is determined by the susceptibility of electrons to excitation from the valence band to the conduction band which is separated by an energy difference called "Bandgap", that depends directly in the dimensions of the QD.

Once we have explained the concept and main propierties of Quantum Dots, I would proceed to explain how do they work. When we excitate electrons of a QD, we boost its electrons into a higher energy level. When we stop applying energy, the electrons would return to a lower energy level therefore a photon is emitted. The photon would have a specific color based on the bandgap of the QDs; bigger QDs produce longer wavelenghts with a lower frecuency whereas the smaller ones produce shorter wavelengths with a higher frecuency. To sum up, smaller dots produce red photons while bigger dots produce violet photons. However, how producing diferent colour photons can help actual medicine?

  • First of all, quantum dots can be design to accumulate in a specific area therefore we create anti-cancer drug target deliverance systems which improves the effience of the treatment and reduces side effects unlike the conventional chemotherapy treatment.
  • Moreover, they can also be used as nanoscopic bulbs of specific colors for studying some cells under microscope.
[li]Finally, they can be very useful in cancer detection in initial phases. Thanks to their nanoscopic dimensions, it allows us to detect methylation processes on DNA, which consist on the addition of a methyl group into a molecule, cytosine in our case. When methylation occurs in some genes, it can affect in the production of
proteins which defeat tumorous cells which makes cancer easier to produce. If we are able to detect these methylation processes, detection of cancer can be much easier. 
[/li][/list]

If you are interested in continue your research on Quantum Dots, I leave you here down below some links to interesting webpages and videos. If you find anything interesting about these structures I would really like to share it with the rest of us!

What are quantum dots?: https://www.trustedreviews.com/opinion/quantum-dots-explained-what-they-are-and-why-they-re-awesome-2916068
Application of Quantum Dots: https://www.explainthatstuff.com/quantum-dots.html
Video: https://www.youtube.com/watch?v=cXNzfR1qaHU

Hope you found it interesting as well as useful,
All the best,
Javier Herrero, The English Centre, Spain.

Re: Quantum dots, another way of defeating cancer?
« Reply #1 on: 31 August , 2018, 16:50:57 pm »
Hi Javier,

I haven't participated in any discussion on this forum so far, but when I saw your post, I was immediately interested in these QD's, especially because my paper is about nanotechnology and cancer.  Thank you for your clear explanation and the links below, I found them really useful.
What I don't understand quite yet, however, is your comment on the zero-dimensional aspect of these structures. It seems to me that matter being in a single point doesn't really make sense with our current understanding of physics. The video you linked below says that these quantum dots are 2-10 nanometers in size. Size tells us how far an object stretches in the dimensions of space-time. But then how exactly are these objects zero-dimensional?
I would really like to touch this topic in my paper as well, but I feel like I need to know more about this in advance.

I look forward to an explanation and, once again, thank you for posting this.
Kind regards,
Hein Brand, Gymnasium Celeanum, The Netherlands

Re: Quantum dots, another way of defeating cancer?
« Reply #2 on: 03 September , 2018, 13:39:43 pm »
Hi Javier,

I haven't participated in any discussion on this forum so far, but when I saw your post, I was immediately interested in these QD's, especially because my paper is about nanotechnology and cancer.  Thank you for your clear explanation and the links below, I found them really useful.
What I don't understand quite yet, however, is your comment on the zero-dimensional aspect of these structures. It seems to me that matter being in a single point doesn't really make sense with our current understanding of physics. The video you linked below says that these quantum dots are 2-10 nanometers in size. Size tells us how far an object stretches in the dimensions of space-time. But then how exactly are these objects zero-dimensional?
I would really like to touch this topic in my paper as well, but I feel like I need to know more about this in advance.

I look forward to an explanation and, once again, thank you for posting this.
Kind regards,
Hein Brand, Gymnasium Celeanum, The Netherlands

Hi Hein,
Thanks for your question as it might help everyone of the forum to understand better some nanotechnology concepts. As you already said, quantum dots measure some nanometers therefore it might seem paradoxical that they are zero-dimensional structures.

We consider that a structure is zero-dimensional when the three dimensions(x,y,z) are measured within the nanoscale, in other words, the maximun length, width and height of the material are under 100 nanometers; the most common representation are nanoparticles. Consequently, a one-dimensional object would have one of the spacial dimensions outside the nanoscale so on and so forth.

Structures that belong to different dimensions would adquire unique propierties, like different electrons confinement and, therefore, a different disposition of the energy levels affecting in their quantum propierties.

If you are interested in learning more about the different dimensions of nano-structures and their quantum effects, here you have some links about the topic:
https://www.ttu.ee/public/m/Mehaanikateaduskond/Instituudid/Materjalitehnika_instituut/MTX9100/Lecture5_NanomatFundamentals.pdf
https://shellzero.wordpress.com/tag/zero-dimension-structure/+

Hope I've anwsered your question and clarify your doubts,
All the best,
Javier Herrero, The English Centre, Spain.

Re: Quantum dots, another way of defeating cancer?
« Reply #3 on: 30 September , 2018, 19:47:03 pm »
Hi everybody again,

We have already talked about Quantum Dots, their propierties and advantages in different fields such as cells imaging or tumors treatment. However, I could read about the cytotoxicity of these devices that indicate that they are not completely innocuous for our organism.

First of all, what is cytotoxicity and why should we know about it? Cytotoxicity is the degree to which an agent, in this case the Quantum Dot, has a destructive action on cells. In other words, the damage that a specific particle generates to the cells of an organism. We should we aware of the particles that can generate this damages in order to evaluate their future medical use.

Having said that, do quantum dots damage our cells? How harmful can they be in our organism? This are really complicated questions to answer because of the ambiguity of opinions: even though most of the reports did not find any negative effects with a small dose, there was a noticiable impact at higher concentrations.  It also depends on the protection of the particle's core; the less protected it is, the faster cadmium and selenium ions would appear(these compounds might result harmful for the organism). Moreover, quantum dots can accumulate in different body parts such as lymph nodes, bone marrow, liver, and spleen without knowing their consecuences.

In conclusion, should we use quantum dots? Or, alternatively, stop using them? Quantum Dots are not harmless at all but it does exist a safe range of carrying through their tasks without any mayor consecuence. Therefore before using quantum dots in medical procedures, an extensive research on these devices needs to be done. What do you  think about this bioethical problem: Are there more positive or negative aspects when using these devices in the organism?

Here you can find different links related with Quantum Dots and their cytotoxicity:
https://www.tandfonline.com/doi/abs/10.1080/17435390.2016.1210691
https://www.ncbi.nlm.nih.gov/pubmed/22775328


Hope you have found the post interesting,
All the best,
Javier Herrero, The English Centre, Spain.