High Precision Biochips of Membrane Mimics for Blood Biomarker Assessment
Multiple sclerosis (MS) is an immune-mediated, inflammatory demyelinating and
neurodegenerative disease of the central nervous system. There has been tremendous effort in
searching of biomarkers that are capable of distinguishing between MS disease and control,
detecting inflammatory activity and the degree of neurodegeneration and demyelination/
remyelination. Despite a list of candidate biomarkers, most of them have not been validated,
and therefore they are not clinically useful. Additionally, many of these marker candidates are
from cerebrospinal fluid (CSF), which are difficult to evaluate routinely. Blood-based biomarkers,
on the other hand, are of great value because of the ease in blood collection by a minimally
invasive manner. However, evaluation of marker candidates in blood has met considerable
difficulty due to issues of low abundance, complex background, and lack of technical capability
to carry out effective screening.
This proposal aims to develop a set of biochips with precise display of lipid antigens in
the form of air-stable, robust membrane mimics arrays. These biochips will be combined with
surface plasmon resonance imaging (SPRi) technique for assessment of biomarker detection in
blood in a high throughput fashion. We will employ lithography and 3D printing technology to
fabricate both the chip substrate and flow cells that enable better control of solution delivery,
eliminate alignment steps and avoid index matching fluid, substantially simplifying the
experimental procedure in SPRi measurement. SPRi is an attractive label-free technique for
microarray analysis, offering high detection sensitivity without the need of a label, and enables
various measurement functions to be carried out with simple instrument configuration. Specific
aims for this work include 1) fabrication of high performance array of membrane mimics for
SPRi with photolithographic methods. A ganglioside array will be constructed with natural and
synthetic lipid hosting environment for studies to understand how molecular display of antigens
affects binding and marker screening in blood samples; 2) fabrication of highly integrated arrays
of membrane mimics with 3D printing technology. We will characterize the performance of
ganglioside arrays in detection of antibodies in blood and test a 3D printed flow system that can
be assembled into biochips to form a cartridge-like unit; 3) assessment of analytical
performance of the high precision biochips for detection of MS biomarkers in blood. The focus is
to construct high quality arrays consisting of known and potential lipid antigens and carry out
performance characterization in terms of sensitivity, working range and cross activity. We will
also run clinical samples of MS patients from commercial sources to evaluate the effectiveness
of this platform for biomarker screening as compared to lipid overlay array method.