• Optofluidics
• Microfluidics for Biomolecular Analysis
• Autonomous Microfluidic Systems
• Directed Microfluidic Assembly
• Nanofluidic Sensors

Optofluidics and Optofluidic Transport

Optical devices which incorporate liquids as a fundamental part of the structure can be traced as far back as the 18th century where rotating pools of mercury were put forth as a simple technique to create smooth mirrors for use in reflecting telescopes. Modern microfluidics has enabled the development of a present day equivalent of such devices centered on the marriage of fluidics and optics which we refer to as Optofluidics. We have a number of ongoing efforts in this area (see below) one of which is in the area of "Optofluidic Transport". Nanofluidic devices hold exceptional promise for future sensing, detection, and species handling in single or “few” molecule environments. It turns out however that when one downsizes fluidic channels one thousand fold, the transport mechanisms that make microfluidic devices so attractive no longer work so well.

In this area we are developing a different approach to small scale transport, using light! In essence, when a molecule or particle is placed within an optical field, a certain number of the photons are either scattered or absorbed when they collide with it. Each of these photons has a momentum given by Planck’s constant divided by its wavelength. These scattering and adsorption events result in momentum transfer to the particle and a net forward velocity that is proportional to intensity. In our approach we exploit the concentrated electromagnetic energy in nanophotonic devices to increase the interaction length with electromagnetic field enabling long distance transport and manipulation individual particles and potentially single molecules. It can be shown that this “Optofluidic” transport has numerous potential downscaling advantages over tradiational mechanisms from faster transport as device size gets smaller and order of magnitude increases in bioanalytical separation resolution.

Our research in this area is supported by the National Science Foundation through our NIRT Grant on Active Nanophotofluidic Systems. For more information on this program visit the NIRT website.

Microfluidic Devices for Biomolecular Analysis

The emerging threat posed by viruses like influenza, adenovirus and small pox necessitates the development of sensor platforms that can diagnose and detect these pathogens at very low levels and with low false alarm rates. Such a system would enable early stage diagnosis of a given infection state before the patient becomes symptomatic and can spread the infection. For large scale population screening applications, low cost, rapidity of results and the ability to track mutations in the virus become equally important.

Towards this end we are developing a series of sensor platforms which fuse our background in nanofluidics, nanophotonics and biomolecular analysis. Broadly speaking our interests are in developing systems which are simultaneously:

1. Sufficiently sensitive and specific to detect pre-symptomatic levels of viral RNA and provide subtype information with very low false alarm rates.
2. Capable of functioning in liquid (raw sera) environments.
3. Provide both target and sample multiplexing capability.
4. Reduce the amount of time required for analysis.
5. Minimize the number of power consuming components in the entire system. This includes reducing or eliminating a number of the traditional sample processing steps that require (most importantly) thermal processing.

Depending on the particular application, the final device solution may be a simple, cheap polymeric device (for large scale screening) or a highly integrated platform which is sufficiently light, low power and autonomous that it can both take and screen a sera sample against the presence of a series of infectious agents at regular intervals (for prognostic screening in high risk situations). We are pursuing elements of both.

Our research in this area is supported by the National Institutes of Health, the Defense Advanced Research Projects Agency and the Cornell Nanobiotechnology Center.

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Autonomous Microfluidic Systems

An autonomous microsystems can be defined as an “individual functioning of its own accord with the ability to interpret and intelligently interact with its environment, whose fundamental physical dimension is on the order of a millimeter or smaller”. In nature autonomous microsystems, in the form of small insect species, have found an ecological niche that is unparalleled. In the last few years the convergence of a number of advancements in MicroElectroMechanical Systems or MEMS technology (including power generation, energy storage, communications, sensing, microfluidics and subcomponent assembly) has opened the door to creating artificial autonomous microsystems.

In our group we are working on the development of a number of different autonomous microfluidic devices for drug delivery, health monitoring and neuromuscular control.

Our research in this area is supported by the Defense Advanced Resarch Projects Agency.

Directed Microfluidic Assembly

We see our approach to self-assembly system as the basis for a new microfabrication paradigm in which programmable, reconfigurable structures are assembled from simple, mass-produceable units.

In essence, a form of “Programmable matter”, a micro-scale set of blocks which can be the platform for many other microsystems from integrated MEMS devices to lab-on-chip bioanalysis devices.

Our research in this area is supported by the Defense Advanced Research Projects Agency and the National Science Foundation.

Active Nanofluidic Sensors

For sensing and detection applications the primary advantage for nanoscale systems is that the volume in which the target is confined is shrunk down to the same scale as that of the target itself. This enables concentration of the detection technique to that same very small volume, thereby significantly amplifying the detection signal. Though there are fundamental advantages to this approach there are also significant challenges in terms of developing fluidic techniques for delivering or attracting targets into the nano-detection site and resolving the detection signal. Our research in this area involves the development of high throughput, high fidelity sensors and sensor arrays. Our current focus is on highly parallel surface phase binding reactions (for single nucleotide polymorphism screening or immunoassay).

Our research in this area is supported by the National Science Foundation.