• Optofluidics and Nanomanipulation
• BioEnergy and Sustainability
• Smartphone enabled Healthy Living
• Solar driven medical diagnostics
• Autonomous Microfluidic Systems

Optofluidics and Nanomanipulation

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.

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 developing fluidically reconfigurable photonic materials and using nearfeild optical devices to manipulate nanomaterials. In some of our recent works we have been able to demonstrate new types of photonic devices that can handle materials as small as quantum dots and carbon nanotubes as well as and biological materials like proteins and DNA.

Our research in this area has been supported by a number of agencies including: the National Science Foundation, the Air Force Office of Scientific Research, the National Institutes of Health, and the Department of Energy. We have also commercialized some of this technology through a venture backed start-up company, Optofluidics, Inc.

BioEnergy and Sustainability

The US Renewable Fuel Standard calls for a near tripling of biofuel production by 2022, including annual production of 4 billion gallons of “advanced biofuels” that achieve a life-cycle greenhouse gas reduction of 50%. In 2011, the National Research Council stated that these goals cannot be achieved without massive innovation in bioenergy production.

Microalgae can be between 100 and 800 times more efficient in terms of oil yield per hectare than current biofuel crops. Unfortunately, the photobiorefineries that are used to produce microalgae have a series of well-documented weaknesses that limit their economic viability. Those weaknesses include: poor distribution of light within the reactor, low organism concentrations, large amounts of water and energy consumption, and inefficiencies associated with harvesting and product extraction.

We are developing transformative new designs for biofuel producing microalgae photobioreactors that enable radically better light delivery and product extraction. These new ultracompact “optofluidic” reactors can have significantly higher areal efficiencies, more efficient solar energy-to-photosynthetic product conversion, and dramatically lower operational energy costs and water usage. In recent papers we have demonstrated the fundamental concepts behind these reactors and are currently working towards upscaling into an integrated prototype system.

Our research in this area is supported by the Department of Energy and the Atkinson Center for a Sustainable Future.

Smartphone Enabled Healthy Living

By 2016 there will be 250 million smartphones in use in the US. We are developing systems that can exploit the ubiquity of smartphone for personalized monitoring of important elements of blood chemistry, like vitamins and micronutrients. Our system exploits a series of microfluidic components, photonic technologies, and standard smartphone capabilities to analyze the content of a blood sample taken from a finger stick. The system is comprised of a reusable “accessory”, that interfaces directly with the USB port of the smartphone and contains the optical interrogation infrastructure, and a consumable “cartridge” or “chip”, that accepts the blood sample, processes it, and conducts the detection assay. Analysis results are displayed to the user via an on-board “app”, compared with optimal levels, and recommendations provided regarding any treatments.

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

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Solar Driven Medical Diagnostics

A need exists for easy-to-use diagnostic tests that can rapidly screen complex samples for a broad swath of bacteria and viruses associated with tropical diseases or to perform molecular diagnostics in settings where traditional techniques such are immunohistochemistry are unavailable. Traditionally this has been done using “simple” easy to use diagnostics, such dipstick assays. These are popular because they require only the insertion of the sample and the fluid transport, sample processing, and detection reaction all occur autonomously without further input from the user or external power. While successful for performing simple detection assays, when applied to the detection of rarer targets in more complex sample matrices they tend to exhibit very poor clinical sensitivity/specificity. Most of the attempts to close the gap between performance and clinical requirements have involved the incorporation of more complex microfluidics, to better process/concentrate the sample, and ultrasensitive nanobiosensors, to detect the target at lower levels. While these approaches do have better clinical performance, the added complexity, cost, and loss of autonomy stand in direct contrast with what makes the “simple” assays popular. We are working on “solar-thermal” microfluidic systems can solve this problem in a way that is quasi-autonomous, easy to operate, and does not require any external energy input beyond ambient sunlight. We are developing a number of different technologies, but most involve converting sunlight into patterned heat and then using that to perform microfluidic processes. We are currently working on some of the fundamental science behind this approach and hope to transition some of our technologies shortly.

Self-Reliant Microfluidic and Biorobotic Systems

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 and “self-reliant” microsystems.

In our group we are working on the development of a number of different autonomous and self-reliant microsystems. One example of our work in this area includes the development of “Insect Cyborg Sentinels” which use embedded drug delivery and electrical elements to control the flight of living insects. We are also developing implantable, glucose powered, microfluidic devices that continuously monitor the bloodstream for the presence of biomarkers indicative of a traumatic injury and, when detected, provide a life extending treatment for it.

Our research in this area is supported by the Defense Advanced Research Projects Agency and the Office of Naval Research.