The ability to manipulate and control the volume and flow of fluids is an important capability in nearly all aspects of chemical engineering and in fields as diverse as manufacturing, health care and biomedicine, petroleum recovery, and consumer products. Nano-Terra provides unique microfluidic capabilities with attractive attributes, including: 1) low cost; 2) the minimization of samples and reagents; 3) the minimization of waste; 4) the separation and detection of molecules with high sensitivity and resolution; 5) short analysis times; 6) low or zero power consumption; and 6) small form factors for devices and processes. We understand how to leverage both the size scale and the unique behavior of the properties and movement of fluids in microfluidic systems.

Our technologies allow for rapid prototyping of microfluidic systems and for integrating components such as pumps, valves, sensors, and optical elements into these systems for practical, functional devices. Our technology portfolio spans the design and prototyping of systems for pathogen detection in water; biosensing; creating monodisperse droplets, foams, and colloids; microdilution and electrochemistry; and generating spatial and temporal gradients for a variety of different applications. Two examples of our technology are described below.

Surface Patterning with Laminar Flow

The flow of fluids at microscale dimensions is dominated by viscous forces and is characterized by a low Reynolds number (a dimensionless quantity that describes the relationship between inertial forces and viscous forces). When streams of miscible fluids flowing at low Reynolds number are combined, the fluids flow side-by-side and do not mix. The only mass transport between the streams occurs by diffusion at the interface of the flowing fluids. We design and fabricate microfluidic systems in which fluids flow in laminar streams and exploit this unique behavior of fluids to create new capability.

The flow of fluids in micro-channels makes it possible to deliver precise volumes of different reagents to specific locations simultaneously and facilitates the patterning of surfaces. When two solutions are infused into a channel at low Reynolds number in which the flow is laminar, the fluids will divide according to their flow rates. As the streams of fluid flow pass through a common channel, molecules or proteins in each solution may be selectively attached to the surface of the channel. The resulting channel will contain regions with different adsorbed molecules. This approach makes it possible to create a variety of structures on surfaces, including complicated gradients of different molecules and proteins, and arrays of electronic circuits or other materials. By manipulating the position and flow rate of fluids using pumps or valves, we deposit multilayer structures of molecules on surfaces that have application in chemical processing, electronics, manufacturing, and consumer products.

Chemical Reactions in Laminar Streams

Laminar flow can also be exploited to control chemical reactions at the interface between streams. When two laminar streams contain solutes that react with each other, a chemical reaction occurs only at the interface between the two fluids and can be used to create and deposit structures on the surfaces of channels. Laminar flow can also be used to etch structures into surfaces. When one of two or more fluids flowing in the laminar region contain a reactant that selectively etches the floor of the channel, complicated patterns can be etched in the floor by manipulating the position and rate of flow of the fluids.

Portable Analytical Systems

The small size of the microfluidic devices we create and the spectrum of technology we have developed for assembling and integrating small components-pumps, valves, detectors and so on-makes these systems particularly attractive as portable detectors for a variety of different chemicals and pathogens. These devices can be operated in remote locations without any electric input, they require very small sample volumes, and can be configured to carry out different assays or detections in parallel. There are a variety of different applications for portable microanalytical systems, including in: chemical synthesis, bioanalysis and biodefense, homeland security, environmental and food-safety monitoring, high throughput screening, and micro-robotics.