A Chemistry Capstone: Synthesizing Nanotubes

Ammara Azam, Class of 2018, was a major in Chemistry and minor in Biochemistry. After a gap year, she will be attending medical school in the Fall 2019. Here she discusses her capstone research project.

My research project was about synthesizing short organosilica nanotubes templated by micelles with closed ends. As a chemistry major, researching in this field gives me a diverse perspective as a premedical student, and I wanted to use this perspective in the world of medicine. After reading and researching about how nanotubes templated by micelles could be used, I found out they could be used as drug delivery vehicles. Micelles arise form surfactant molecules that possess both hydrophobic (water hating) and hydrophilic ( water loving) properties. When introduced to water or aqueous solution will cluster together to form a core of a hydrophobic headgroups and a surface of hydrophilic headgroups. This micelle is then able to deliver nonpolar compounds in polar regions. So, I decided to conduct my next research project on the topic of drug delivery. I wanted to create possible drug delivery vehicles from my oragnosilica nanotubes, but I needed to shorten them because they were normally too long and clumped together to provide any possibility for drug delivery. To analyze my samples of nanotubes, I mainly used TEM (Transmission electron microscopy) allowing me to see the sample’s morphology.

Ammara in the lab

            The objective of research is to try and use different methods to achieve the results desired, and even when one does not retrieve what was desired from an experiment one should still consider that invaluable information that could help in a different way. With that in mind I started by recreating a synthesis previously conducted where the nanotubes possessed short length, the only difference would be that I was using some different reactants. Through TEM I saw that I was not able to retrieve short tubes, instead I retrieved well-defined tubes, which were a good sign because the tiny change I made did not produce completely altered tubes. Now my main task would be to shorten these tubes. First, I tried to use sonication which involves vibrations created from ultrasound, that may be able to break the tubes and shorten their length. This procedure in TEM showed to produce short tubes, but they were not large in amount and an exact time for sonication without breaking ends would be too difficult/ time consuming to pin point.

The next thing we tried was decrease the amount of the framework precursor (the template for the micelles), this had been done because it was noticed in other projects that decreasing the framework precursor decreased the length of tubes, and this produced some very interesting results. Through TEM I saw some asymmetrical tubes that are very uncommon, pushing my research towards synthesizing short asymmetrical tubes. Now I needed to increase their yield so I tried to increase the amount of swelling agent (it expands the inside of the micelles). However, TEM seemed to indicate that this seemed to increase their diameter not their amount, still this allowed us to see that the diameter could be increased.

            Going over all my experiments, the method of attack was to try something that could possibly lead to short tubes, or what we wanted and trying it out. Then, we would look at the results and see if they could be used some way towards the current project or in other respects. If I continue this project I plan to do just the same, try different things out and see their results. Through this process my goal will still be trying to increase the yield of short tubes with closed ends, whether they are asymmetrical in character or not.