Good Things in Very Small Packages
November 15, 2012鈥擶ith research focused on nanomaterials, Assistant Chemistry Professor Jong-in Hahm gets big results from the smallest of packages.
Hahm recently received the 2013 Rising Star Award from the American Chemical Society鈥檚 Women Chemists Committee (WCC). This spring, she will present some of her latest research on one-dimensional nanomaterials to the WCC. 鈥淚 will showcase all of the nanomaterials that we grow and synthesize in the lab. And how we tweak their properties to help biomedical sensing,鈥� she said.
Although many of her projects have applications in medicine, Hahm always investigates the many ways that her materials can be used. 鈥淪ince you can tweak the physical, electrical, optical, or magnetic properties of these materials, it comes down to where you need [them] the most. You鈥檙e trying to design your materials to fit that purpose,鈥� she continued.
Before they can make any changes, Hahm and her lab group start with a fundamental understanding of each material. 鈥淲e spend a lot of time trying to understand the basic principles that are relevant to different properties of these nanomaterials,鈥� she said. 鈥淭hese properties are interrelated, so if you change one property, it may affect another one,鈥� she explained.
Hahm is currently working with carbon nanotubes, which measure about 1.5 nanometers in diameter. (A nanometer is 1 billionth of a meter.) 鈥淸They are] about the width of double-stranded DNA,鈥� she said. Hahm uses the size and sharpness of a carbon nanotube to enhance biomedical sensing. Spotting genetic variances or markers can be difficult because each individual has DNA from their mother and father. 鈥淭here鈥檚 really no good way to differentiate two copies of the chromosome鈥攚hich came from where.
鈥淭he physical nature of the carbon nanotube will allow us to look at any sort of variance on the gene under investigation. Without it, you can鈥檛 really see the mutation sites on the gene.鈥�
Whether working with carbon nanotubes or zinc oxide nanorods, Hahm can alter significant properties by changing the diameter of the material. According to Hahm, this process has been around from some time and can easily been seen in many stained-glass windows.
鈥淭hose colors are coming from nanoparticles, [but] they didn鈥檛 call them nanoparticles then,鈥� she said. Flecks of gold and silver in the windows demonstrate how properties can change by making things smaller. 鈥淭hese gold particles, if you make them 25 nanometers in size, all of sudden they glow red. But double the size to 50 nanometers and they glow green,鈥� she explained. However, these changes in optical properties do not occur after the gold particles are more than several hundred of nanometers in diameter. 鈥淚t only happens at the very small scale.鈥�
The process is now easily explained in modern scientific terms. 鈥淲hen things become smaller鈥攕maller to the one-thousandth of hair thickness鈥攎aterials鈥� properties can be manipulated by fine-tuning the size and shapes of materials,鈥� she explained.
Nanoparticles are not only in our stained-glass windows but in a variety of consumer products. Zinc oxide nanoparticles in sunscreen absorb UV rays and protect the skin. Carbon nanotubes are used to strengthen the frames of tennis rackets and bicycles. Hahm鈥檚 own research materials have been applied mainly in the biomedical field: improving protein arrays, enhancing biomedical sensors, and establishing more determinative and quantitative medical experiments.
After two years at Georgetown, Hahm is continuing to grow relationships with other faculty on campus. These collaborations sometimes happen formally, but they often happen from casual conversations about research problems. 鈥淎ll of a sudden you realize that some of your materials can help them solve [their] problem.鈥�
With the ability to change the physical, optical, magnetic, or electrical properties of materials, Hahm is looking at new applications. 鈥淎lthough our main focus in terms of nanomaterials鈥� applications is currently in the areas of biomedical detection, we have recently expanded our nanomaterials research to the areas of energy.鈥�
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