The notion of sample preconditioning, or pretreatment, as a micro-unit operation in a Lab on a Chip (LOC) system has
yet to be realized in commercial practice. As is well known, Biomarker detection in complex, biological samples, such
as blood, requires a series of pretreatment steps to enable detection of specific markers. On chip, such a process usually
relies on "off-chip" sample pretreatment prior to "on-chip" analyte manipulations and detection. Presented in this paper
is a PDMS, pretreatment chip based on the design of Oddy et al.1 with a view to enable a self-contained LOC platform.
The chip was designed to directly manipulate the suspended species while adjusting fluid properties using buffer
volumes less than 1 ml. Using previous literature related to capillary electrophoresis, a bench-scale pretreatment protocol
was developed to tune specific fluidic parameters to an optimal range, namely pH, conductivity, and viscosity. A PDMS
device was fabricated and used to combine a raw, bovine serum sample with specific buffer solutions. Off-chip
electrodes were used to induce DC-electrokinetic micro-mixing of the target analyte in the mixing chamber, where a
homogeneous analyte distribution was achieved in less than one second using an 800V DC pulse wave. Additionally, the
desired solution viscosity and pH were achieved using less than 1 ml of buffer solution. Adjustment of sample
conductivity, which is driven by sample fluid volume, remains an open area of research.
Biodetection instrumentation that is capable of functioning effectively outside the controlled laboratory environment is
critical for the detection of health threats, and is a crucial technology for Health Security. Experience in bringing
technologies from the basic research laboratory to integrated fieldable instruments suggests lessons for the engineering
of these systems. This overview will cover several classes of such devices, with examples from systems developed for
homeland security missions by Lawrence Livermore National Laboratory (LLNL). Recent trends suggest that front-end
sample processing is becoming a critical performance-determining factor for many classes of fieldable biodetection
devices. This paper introduces some results of a recent study that was undertaken to assess the requirements and
potential technologies for next-generation integrated sample processing.