NSF Award Abstract - #0304483

AWSFL008-DS3

NIRT: Molecular Sensing and Actuation by CMOS Nonvolatile Charges with
Independently Addressed Nanoscale Resolution

Abstract

INTELLECTUAL MERITS The purpose of this proposal is to develop nano-scale resolution of sensing and actuation between silicon CMOS devices and molecules in fluids. We will investigate the implementation of this interface by nonvolatile charges stored in lithography-pattern floating gates, self-assembled metal nanocrystals embedded in SiO2, or surface traps with scan-based direct charging. The nonvolatile charge will interact with the silicon devices in the Flash memory manner as in the commercial technology of the scan disk in digital camera and camcorders. The positive and negative nonvolatile charge will serve as attractive or repulsive receptors like remote cation and anionic ends to the molecules in fluids. We will investigate the force magnitude and resolution by different implementation strategies. We will design and conduct realistic test cases including single molecule trapping/actuation of fluorescence labeled DNA fragments, and protein recognition based on surface charge distribution instead of global properties such as size and isoelectric point. We will also investigate the influence from microfluidic device integration and autonomous operations, though a complete system design is out of our scope. We will formulate predictive modeling and simulation tool suites for equilibrium molecular structures and their movement toward a surface charge sheet in an environment mediated by the ambient ion charges in fluids. From our preceding NER work (ECS-0210743), we have preliminary experimental evidence that the goals we propose in this NIRT are practically achievable.

MAJOR APPLICATIONS In addition to the intellectual studies on the interface of silicon devices and molecules, successful implementation of this new interface concept can potentially revolutionize the biological measurements, biomedical microscopy, and pharmaceutical practices. By functionally mimicking the sensory, digestive and immune systems in biological systems with electronic receptors, new systems for molecule actuation, artificial ion channels without applying bias to fluids directly, protein recognition, and eventually biomedical treatments for cell-level diseases can be envisioned. The tight integration with present silicon technology enables affordable production in large volumes.

BROADER IMPACTS Nanotechnology has caused major transformation in our society. Successful interface between silicon devices and biological molecules will not only be intellectually interesting and commercially valuable, but will also have many social and legal implications. The technology developers and the general public need more overall awareness on these impacts. In addition to our existing outreach channels to penetrate nanotechnology development to K-12 and undergraduate education for broader awareness and diversified perspectives, we have formulated a realistic plan to include law school expertise to study the legal and social implications. In the beginning, the technology developers need to be educated on reasons for government regulation and the nature of risk. Test cases will then be designed collaboratively for course discussions. These materials will be assessed from pragmatic evaluations, proliferated according to the level of understanding, and then promoted to various audiences including engineering, non-engineering and high school curriculum. We will also initiate a new outreach program to Wells College (a womens college 30 miles away from Cornell main campus) in the form of exchange seminars, short intern period for general awareness, and assessment of test cases from an independent group.