Functional DNA Nanotechnology and Its Applications in Environmental Monitoring, Food Safety, Medical Diagnostics and Imaging

 Selective sensors are very ueseful for on-site and real-time detection in environmental monitoring, food safety, medical diagnostics and imaging. Despite much effort, few such sensors are commercially available. Professor Lu has identified challenges in both fundamental sciences and in technological developments, and has made significant progresses in meeting these challenges.

In fundamental sciences, designing selective sensors based on a single class of molecules for a broad range of targets remains a significant challenge. Most processes are on a trial and error basis where successes in designing agents for one target can be difficult to translate success in designing agents for other targets. To meet these challenges, Professor Lu has been able to use in vitro selection or SELEX to obtain DNAzymes, a new class of metalloenzymes that use DNA molecules exclusively for catalysis, and aptamers, a new class of nucleic acids that rivals antibodies, that can bind targets of choice strongly and specifically, and use negative selection strategy to improve the selectivity. By labeling the resulting DNAzymes and aptamers, callled Functional DNA with fluorophore/quencher, gold nanoparticles, gadolinium or supermagnetic iron oxide nanoparticles, Professor Lu has developed new classes of fluorescent, colorimetric and MRI agents for metal ions and a wide range of other targets with high sensitivity (down to 14 pM) and selectivity (> 1 million fold selectivity).^1-3

In technological development, there are still significant barriers by the public to adopt new devices or technologies developed in academic laboratories. Professor Lu is exploring ways to overcome this barrier by taking advantages of the wide availability and low cost of the pocket-sized electrochemical devices such as glucose meters to detect many non-glucose targets, ranging from vitamins (e.g., biotin), to toxic metal ions (e.g., Pb²⁺), adultrants (e.g., melamine), toxins (e.g., afflatoxins), and diseases (e.g., cancer and anthrax).^4-6 Since in vitro selection can be used to obtain functional DNA to bind a wide range of targets, this approach can be readily used by the general public to detect many other targets in environmental monitoring, food safety, medical diagnostics and imaging.

1. a) Juewen Liu, Zehui Cao and Yi Lu, Chem. Rev. 109, 1948–1998 (2009); b) Hang Xing, Kevin Hwang, Ji Li, Seyed-Fakhreddin Torabi, Yi Lu, Curr. Opin. Chem. Eng. 4, 79-87 (2014).

2. Juewen Liu and Yi Lu, J. Am. Chem. Soc. 125, 6642-6643 (2003).

3. Juewen Liu, Andrea K. Brown, Xiangli Meng, Donald M. Cropek, Jonathan D. Istok, David B. Watson, Yi Lu, Proc. Natal. Acad. Sci. USA, 104, 2056-2061 (2007).

4. Yu Xiang and Yi Lu, Nature Chem. 3, 697-703 (2011).

5. Yu Xiang and Yi Lu, Anal. Chem. 84, 4174-4178 (2012)

6. Tian Lan, Yu Xiang, Yi Lu, in Mobile Health Technologies: Methods and Protocols, Avraham Rasooly and Keith Herold (Eds), 99-110 (2015).