Summer Scholar Kaila Holloway experiments with tiny chemical sensors that can indicate tumor changes.
Chemicals like nitric oxide and hydrogen peroxide can promote cancer growth. MPC-CMSE Summer Scholar Kaila Holloway is working in the lab of Michael S. Strano, Carbon P. Dubbs Professor in Chemical Engineering at MIT, to develop tiny chemical sensors to detect their concentrations near tumors in the body.
“I'm actually making nitric oxide and hydrogen peroxide sensors, so it's basically DNA-wrapped single-walled carbon nanotubes,” Holloway, a rising senior at Howard University, explains. “I'm going to be detecting hydrogen peroxide and nitric oxide in different cells.” In the lab, she synthesizes two different types of DNA.One type of DNA, ds(AT)15, works to detect nitric oxide in the cells, while another type of DNA, ds(GT)15, works to works to detect hydrogen peroxide in the cells.
Holloway’s summer project is supervised by Freddy T. Nguyen, M.D., Ph.D., who is a postdoc in the Strano Research Group. “Really the value of these sensors is that they're involved in a lot of different pathways in the development of cancer as well as the treatment of cancer and the regression of cancer,” Nguyen says.
Holloway brings to the project her experience at Howard synthesizing silver phosphate nanoparticles and encapsulating them in polymers. At MIT, she is a learning a new skill, how to use the absorbance spectroscopy instrument. She synthesizes the sensors, first diluting d(AT)15 and d(GT)15 from their original concentrations, before testing them in the absorbance spectroscopy machine. She takes the samples that she diluted, and puts them in glass cuvettes, which are then placed inside the machine. The computer has software that can analyze it and measure their optical absorbance. The next step is to introduce the hydrogen peroxide to the DNA-wrapped carbon nanotubes and measure their fluorescence.
|2017 MPC-CMSE Summer Scholar Kaila Holloway is experimenting with single-walled carbon nanotubes wrapped with DNA that can act as tiny chemicals sensors to detect changes in hydrogen peroxide and nitric oxide, which are indicators of tumor responses to treatment. Holloway is working in the lab of Michael S. Strano, Carbon P. Dubbs Professor in Chemical Engineering at MIT. Photo, Denis Paiste, Materials Processing Center.|
“We're going to test its response to hydrogen peroxide so we're going to measure the fluorescence intensity at the peak,” she explains. “It either increases or decreases once we introduce hydrogen peroxide to the sensor.”
Later, Holloway will start working with cells and see how the sensors work inside the cells with hydrogen peroxide. In the lab, displaying a graph showing the absorbance spectrum from one of her samples, Holloway explains, “This is for the ds(AT)15 sample at different wavelengths. The sample can take in different amounts of light, and that's what the different peaks are. The absorption spectrum basically just allows us to see how different subtypes of the carbon nanotubes detect light differently or absorb light differently, then we can further test that with the sensor, to see which one works better, for either the hydrogen peroxide or the nitric oxide.” Holloway also hopes to make a 3D tumor model during her summer internship.
Nguyen explains that “The goal of this project is ultimately that with patients we can be able to get an answer as to whether a treatment is effective within a matter of hours or days, as opposed to what patients currently have to do is wait weeks or months actually to see physical size changes of the tumor burden.”
Holloway’s internship is supported in part by NSF’s Materials Research Science and Engineering Centers program [grant DMR-14-19807]. Participants in the Research Experience for Undergraduates, co-sponsored by the Materials Processing Center and the Center for Materials Science and Engineering, will present their results at a poster session during the last week of the program. The program runs from June 15, 2017, to August 5, 2017, on the MIT campus in Cambridge, Mass.
– Denis Paiste, Materials Processing Center
July 31, 2017