Optofluidics and Optofluidic Transport

Optofluidic Transport. Using radiation pressure and other near feild forces in photonic devices can be used to trap and transport species in microfluidic devices.

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 including: reconfigurable photonic materials, photonically enabled biological identification, thermo-optically enabled programmable matter, and new developing new methods for manipulating nanoscale materials and DNA.

Our research in this area is supported by a number of agencies including the National Science Foundation through our NIRT Grant on Active Nanophotofluidic Systems (visit the NIRT website), the Air Force Research Labs and the Defence Advanced Research Projects Agency.

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.

Nanoscale Optofluidic Devices for Viral RNA Detection In this work we are developing “Nanoscale Optofluidic Sensor Arrays” for multiplexed detection of viral RNA (specifically Dengue and Influenza). The approach we use combines our backgrounds in fusing nanofluidics with nanochemistry (to provide specificity) and nanofluidics with nanophotonics (to provide sensitivity).

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:

Sufficiently sensitive and specific to detect pre-symptomatic levels of viral RNA and provide subtype information with very low false alarm rates.
Capable of functioning in liquid (raw sera) environments.
Provide both target and sample multiplexing capability.
Reduce the amount of time required for analysis.
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.

Autonomous and Biologically Enabled Microfluidic Systems

Autonomous Microfluidic Devices. We are developing a variety of autonomous microfluidic devices for medical diagnostics and drug delivery.

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 neuromuscular control and Insect Cyborgs.

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

Directed Assembly and Programmable Matter

Directed Microfluidic Assembly. The overall goal this research is do develop a new method of microfluidically directed hierarchical assembly of mechanically, electrically or optically active subelements.

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

Electroactive Nanowell Devices. Electrically modulated control of attraction, storage and repulsion of particles from electroactive nanowell devices. Download this movie to see an example of the transport dynamics of attraction on the microscale.

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.

Manipulating DNA with Nanophotonic Devices. Here we demonstrate the ability to use optical forces on the nanoscale to grab and manipulate single strands of DNA.

Microfluidically Enabled Insects. We have recently demonstrated the ability to manipulate insect flight behavior using implanted microfluidic devices.

Thermorheologically Enabled Programmable Matter. In recent works we have developed techniques for controlling microfluidic assembly processes using temperature responsive fluids.

Nanoscale Optofluidic Integration. Here we are using multilayer soft lithography to fluidically address and tune photonic structures at the nanoscale. Top image shows schematic of multi-layer soft-lithography coupling with nanophotonics. Bottom image shows an SEM image of nanoscale precision fluidic addressability in a photonic crystal.

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