Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations.

A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction).

The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central lab-based chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

Microfluidic control is essential for a successful lab-on-a-chip. This innovation is capable of analysis of bodily fluids such as blood, sweat, tears, serum, plasma, cerebrospinal fluid, sweat, and urine. It can be configured as a mobile or handheld instrument for use at bedside, ICU (intensive care unit), ER (emergency room), operating rooms, clinics, or in the field. Alternatively, it can be configured as a benchtop system. The chip can be configured to perform on-chip all-electrical micropumping; i.e., the chip can be configured to operate with no off-chip pressure sources or syringe pumps. Additionally, it can perform many simultaneous, parallel operations on nanodroplets, thereby expediting production of results.

To aid in processing the microfluidic samples, an improved design for loading a droplet actuator includes a top substrate that combines glass with one or more other materials that are easier to manufacture. Examples of such materials include resins and plastics. The glass-plate portion covers the droplet operations area of the droplet actuator, providing a flat, smooth surface for facilitating effective droplet operations. The plastic portion has one or more openings that provide a fluid path, from an exterior well, into the gap of the droplet actuator. The substrates are associated with electrodes for conducting droplet operations such as droplet transport and droplet dispensing.

This work was done by Michael G. Pollack, Vijay Srinivasan, Allen Eckhardt, Philip Y. Paik, Arjun Sudarsan, Alex Shenderov, Zhishan Hua, and Vamsee K. Pamula of Advanced Liquid Logic, Inc. for Johnson Space Center. For further information, contact the JSC Innovation Partnerships Office at (281) 483-3809.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Advanced Liquid Logic Inc.
615 Davis Drive Suite 800
P.O. Box 14025
Research Triangle Park, NC 27709

Refer to MSC-24283-1/553-1/4-1, volume and number of this Medical Design Briefs issue, and the page number.