Grad News Forum

Teague Enterprises TE-10 smoking system equipped with two exposure chambers.

Recently, Yuan Liu and Sadik Antwi-Boampong of the Department of Chemistry published a paper entitled “Detection of Secondhand Cigarette Smoke via Nicotine Using Conductive Polymer Films” in collaboration with their advisor, Joseph J. BelBruno, Mardi A. Crane-Godreau of the Department of Microbiology and Immunology, and Susanne E. Tanski of the Department of Pediatrics and the Dartmouth-Hitchcock Norris Cotton Cancer Center. The paper, published in Nicotine and Tobacco Research, described a sensor that the group had developed that detects levels of secondhand and even thirdhand smoke.

In the sensor, a polyaniline polymer is coated onto a chrome and nickel electrode grid, creating a conductive layer. The polymer is then protonated with acid, which then interacts with nicotine (a base), and resistance is measured across the sensor. Measurements are taken in a smoking machine, where cigarettes are spun and smoked, and the smoke is then shuttled into the exposure chamber, where the sensor is located. After each round of secondhand smoke exposure, the sensor is regenerated with purges of fresh air. The sensor is so sensitive that it even picks up levels of thirdhand smoke (smoke that has been absorbed onto surfaces such as walls, furniture, clothing, etc.).

Liu, Antwi-Boampong, and their collaborators have developed this sensor and its program interface to be used for commercial purposes to test levels of second and thirdhand smoke in homes, especially where children live. The sensor is innovative because it measures data in real-time, as compared to other sensors, which can only analyze data after full collection.

Molly Croteau, also a PhD student in the Department of Chemistry, recently sat down with Antwi-Boampong to learn more about this innovative project.

Molly Croteau (MC): How did you and Liu come to work on this project?

Sadik Antwi-Boampong (SA): This is Liu’s thesis research, and I assisted him. Our advisor, Professor BelBruno, had the idea to build this sensor.

MC: How long have you been working on this project?

SA: We’ve been researching this sensor for about three and a half years.

MC: Three and a half years is a long time—the public only sees the results. What were some of the biggest obstacles to overcome?

SA: We invested a considerable amount of time in material selection and sensor design because we wanted a simple but effective device. Once we had chosen a polymer, we then had to optimize it to provide maximum efficiency. We also had to choose a substrate and electrodes that would work well as the sensor platform. We actually started with a glass substrate, but ultimately decided against it because of its fragility and difficulty in machining. In the end, we switched to a silicon substrate with a chromium-nickel interdigitated electrode grid fabricated using conventional lithography. We also had to figure out the best solvent and optimal film thickness for the sensor layer. Thus, in our materials approach for this work, the design and selection of materials posed some challenges.

MC: The paper mentions that this sensor measured 0.75 ppb nicotine for 2 cigarettes smoked, and 1.11 ppb for 3 cigarettes smoked. What is the safe value for nicotine exposure?

SA: The median lethal dose for nicotine is about 30 mg, and as you would expect, systemic exposure to minute levels of nicotine through secondhand smoke aerosol can have serious effects on an individual. Therefore, we are really happy that our sensor is sensitive enough to measure in the ppb range.

MC: How would the user regenerate the sensor?

SA: A jet of air can fully regenerate the sensor for multiple uses.

MC: The system is relatively inexpensive—the sensor/chip costs about $30, and the computer costs anywhere from $25 to $300. In addition, the sensor can be regenerated for multiple uses. How else is your system better than what is already out there for secondhand smoke detection?

SA: In addition to being considerably cheaper, our sensor is significantly more sensitive and user-friendly than the traditional sensors already on the market. Our sensor measures data in real-time and gives that information right away to the user. Detection systems out there now only collect the data, and then it needs to be analyzed by experts and sent back to the user. Our sensor would allow the user to see right away the levels of secondhand smoke that they are being exposed to.

MC: This project involved a lot of components and different areas of research. Have you collaborated with anyone?

SA: Oh, yes. Professor Mardi Crane-Godreau works with us in our smoking chamber experiments at Dartmouth-Hitchcock Medical Center. Dr. Susanne Tanski is a pediatrician, who will be working with us to collect data from her patients who have parents who are smokers. We also collaborated with the Thayer School of Engineering on our early glass sensor fabrication and lithography work, the Dartmouth Electron Microscope Facility in Remsen on obtaining microscopic images of our sensors, the Computer Science Department on coding the program for the sensor, and the Department of Physics and Astronomy on the circuitry of the sensor. This project was very cross-disciplinary.

MC: What are your future plans for this project?

SA: Right now we are currently enhancing the sensor for selectivity and sensitivity. We are looking into different sensor layer architectures and actively exploring different ways we can make the sensor better. Also, we are looking into detecting levels of cotinine, which is what nicotine is converted to in your body. We have partnered with Professor Crane-Godreau to conduct new experiments to qualitatively and quantitatively demonstrate the sensor’s efficacy.

MC: It sounds like you are really on your way to helping people quickly monitor secondhand smoke levels.

SA: We are! In addition, I am also working on a sensor that can detect levels of formaldehyde, a ubiquitous molecule that leaches from construction materials and many household products. It has recently been determined that formaldehyde causes a variety of cancers, including myeloid leukemia, so that is the motivation for the project. There are no affordable sensor systems now that can effectively and selectively detect formaldehyde, so I am hoping to use a simple materials chemistry approach to construct a sensor that can sense formaldehyde vapor in real-time.

To read more about Liu and Antwi-Boampong’s research, see the Dartmouth Now.

by Molly Croteau

Many graduate students will one day go on to be professors in their own right. Gaining knowledge in the realm of teaching can be acquired through classes and overall graduate school experience. However, one skill that graduate students may not acquire during their studies is the ability to manage a successful lab. The Department of Microbiology and Immunology’s Professor George O’Toole discussed some helpful points related to lab management as a part of the “Becoming a Faculty Member” series on January 25.

Professor O’Toole made the comparison that “running a lab is like running a small business.” The revenue is your grant money, your products are papers, posters, and seminars, and it is important that your employees are happy. He stressed that in managing a successful lab, you need successful people. Don’t be afraid to choose students who will work well with your teaching and management style and that you know will be successful under your guidance. If conflict should arise or a student is not accomplishing what you think he or she should be, it is wise to clearly go over your lab expectations with that student and discuss how he or she can improve his or her performance to meet those expectations. Obtaining constant feedback from your students helps to improve your management of their graduate student careers.

Professor O’Toole warned seminar attendees that it is necessary to seek out training in lab management. There are no formal training courses, nor will someone explicitly sit you down and advise you on how to accomplish this task. He remarked that he was fortunate to have both graduate and postdoctoral advisors who taught him about lab management, but this is hardly the case for everyone. Professor O’Toole advised attendees to use their experiences now as graduate students to start planning how they would run their labs in the future. It is never too early to start thinking about the details—taking note of good and bad management strategies now will aid you in making better decisions later on.

Professor O’Toole finished his talk by emphasizing the importance of seeking help when it’s needed. He stressed how important it is to ask for advice as a young professor. Colleagues, as well as those in human resources and other university support services, can help you in managing your lab or even in writing grants to run a successful lab. You do not have to try to attempt a new and somewhat scary feat on your own; you just have to know how to ask for help!

by Molly Croteau

Photo from Microbiology and Immunology Website

The students in the Microbiology and Immunology Program have had a remarkably successful year, receiving a variety of awards and recognition from on and off campus. Several of our students graduated this year: Kevin Hart, in Brent Berwin’s lab; Kyle Cady, who worked with George O’Toole; Adel Malek, Amy Piispanen, and Diana Morales, in Professor Deborah Hogan’s lab; Kimberly Spotts, in Ambrose Cheung’s group; and Jarrad Marles, who worked with Ron Taylor. Christina Megli, who graduated with a PhD from the Taylor lab, is now working towards an MD.

Eleanor Clancy-Thompson, a PhD candidate in David Mullin’s lab, was awarded a Research Scholar Award, from the Joanna M. Nicolay Melanoma Foundation, which supports exceptional graduate students. Eleanor was one of nine students awarded this prize in a national competition. Ana Posada, in Ambrose Cheung’s lab, was awarded a Science, Technology, Engineering, and Mathematics (STEM) GK-12 Fellowship, from the National Science Foundation, meant to introduce current research into the K-12 classroom, and teach fellows to make their research more accessible—the fellowship includes training in communication skills and teaching techniques.

Allia Lindsay and Amy Piispanen, in the Hogan lab, published a paper in Eukaryotic Cell that was spotlighted in Microbe and cited as an article of significant interest by the editors. In Professor George O’Toole lab, Amy Baker was awarded an NSF Graduate Fellowship, Dae-Gon Ha was named the 2012 Rosalind Borison Fellow, and Laura Filkins was appointed to the Molecular and Cellular Biology (MCB) Training Grant, and attended a week-long intensive microscopy course at the Mount Desert Island Biological Laboratory where she was awarded for her outstanding presentation of the work she performed during the course.

Dae-Gon is also doing an independent study project at Celdara, a local biotechnology company. Matt Deberge, in Professor Richard Enelow’s lab, was named the James W. McLaughlin Travel Awardee at the 2011 Annual IHII/McLaughlin Colloquium at University of Texas Medical Branch, and he was elected as an Albert J. Ryan Fellow in both 2011 and 2012.

Students in every lab have had successes this year, in their research, presentations, and publications, and we’re looking forward to another year of great work and accomplishments.

Immunology Retreat

The students of the Microbiology and Immunology Program have had a remarkably successful year, receiving a variety of awards and recognition from on and off campus. Several students graduated this year: James Cripps in James Gorham’s lab, Michael Molloy who worked with Edward Usherwood, Peter Newell in the O’Toole lab, Karina Pino-Lagos in Randy Noelle’s group and Uciane Scarlett, who worked with Jose Conejo-Garcia. Kevin Hart, Adel Malek, Diana Morales, and Amy Piispanen successfully defended and will attend the 2012 commencement.

Raquel Martinez, a recent graduate of the program and a member of the Taylor lab, was awarded a position in the NIH sponsored Medical and Public Health Laboratory Microbiology Training Program—there is only one such award annually nation-wide. Jarrad Marles, also of the Taylor lab, was awarded a two-year fellowship through the National Biosafety and Biocontainment Training Program (NBBTP). The program is a partnership of the NIAID, DOHS, and NIH, designed to “train Fellows specifically to support Biosafety Level 3 and Level 4 research environments.”

Kyle Cady in the O’Toole lab was named the 2011 John H. Copenhaver, Jr. and William H. Thomas, MD 1952 Fellow. Rameeza Allie, a PhD student in the Usherwood lab, was awarded a Borison fellowship this year. Kate Byrne, a PhD student in the Turk lab, won a student poster award at the New England Immunology Conference and was invited to the New York Immunology Conference to speak about her work. Recent graduate from the Hogan lab, Adel Malek, will join the lab of HHMI Professor William Jacobs at Albert Einstein and Diana Morales is going to Harvard Medical School to work with Dr. Roberto Kolter.

Kim Spotts-Wallace, a former PhD student in Ambrose Cheung’s lab, was awarded a SMART scholarship through the American Society for Engineering Education—the award funded a portion of her PhD work and involved spending her summers building a tool for predicting and analyzing multiple factors during vaccine/antimicrobial drug development, including cost, schedule, and labor. Following the fellowship, Kim secured a position as the Deputy Project Manager for the Broad Spectrum Bacterial Countermeasures Program through the JPEO (Joint Program Executive Office) of the Department of Defense.

by George O’Toole