The fundamental goal of this program is to develop a point of care high fidelity, aptamer based assay for genital Chlamydia infections that allows fast and quantitative determination of levels of infection with different sero-types of Chlamydia trachomatis. The ultimate goal is to have this assay be integrated into an inexpensive portable microfluidics device that can be used in any physician's office. This device will provide vital information on important health aspects of some underserved populations. The key element is a family of serotype specific DNA aptamers that exhibit very high sensitivity and specificity (99,999 %) of detection of C. trachomatis. The DNA aptamers act as an enhanced replacement for the antibodies and specifically react with the target microorganisms in a microfluidic version of sandwich ELISA realized in a portable hand held device recently developed by one of the team members, Claros Diagnostics (Cambridge MA). A two phase program is proposed. The Phase I culminates in the validation of the aptamer assay for Chlamydia trachomatis in the International STD, Respiratory, and Biothreat Research Laboratory of Johns Hopkins University (Baltimore, MD). The Phase II of the program will focus on bringing together the detection biochemistry and instrumental grid in a new point of care (physician's office) assay for Chlamydia trachomatis. The preliminary data accumulated by the proposal team encompass extensive experience and profound knowledge of clinical and societal aspects of C. trachomatis infections brought by the group of Professor Charlotte A. Gaydos, Johns Hopkins University. Claros Diagnostics'microfluidics detection platform realized as a small device is capable of dealing with microscale bio-samples and allows rapid reproducible handling of microliter liquid volumes. The novel aptamer selection technology has been developed by Infoscitex Corporation and has been successfully applied to produce high quality DNA aptamers for the US Department of Defense applications, such as detection of anthrax toxin and infectious prions.
Currently, the most sensitive diagnosis of genital chlamydiosis employs quantitative real-time polymerase chain reaction qRT-PCR. As recently reported, the major outer membrane protein (omp-1) -gene and a L- serovar-specific region of the polymorphic protein H (pmp-H) -gene could be used to detect C. trachomatis. The detection limit of each real-time PCR was 50 genome copies per reaction (Schaeffer, 2008). However, difficulties in distinguishing some of the C. trachomatis sero-variants by this method were acknowledged by the authors. If implemented on a large scale, the costs of RT-PCR diagnosis for C. trachomatis and time to diagnosis may, unfortunately, become prohibitive for the underserved populations. Therefore, a rapid and affordable point of care analysis of patient-derived specimens can revolutionize the field of diagnosis of genital chlamydial infections. Our technology will provide physicians with an inexpensive simple assay and unambiguous readout that will suggest, or rule out, the necessity of further treatment right in the physician's office. In summary, the assay-device combination proposed here will reach the underserved populations who can be much more fully protected when enabled with point of care diagnosis of genital chlamydial infections.
