Multiplexed Paper-Based Blood Test for Early-Stage Colorectal Cancer Screening

Preventive services have been emphasized as essential components of the medical care system. However, the disparities in cancer incidence and mortality rates experienced by vulnerable populations are evident in rates of screening for colorectal cancer (CRC). While community health centers can play an important role in addressing these disparities, their current operations are not set up to ensure that every eligible patient receives timely CRC screening. The current patient self-test relies on a fecal immunochemical test that is plagued with low rates of positive early cancer identification and difficulty in excluding non-neoplastic causes of intestinal bleed. Until a low-cost, simple, and highly accurate diagnostic method is developed, screening rates in minorities, uninsured, and low-income populations will likely remain low. The long-term goal of this project is to improve the accessibility of CRC screening through the development of a new, on-demand diagnostic approach that has potential to enable self-testing at home followed by signal development and diagnosis after sending the test to a central facility (for example by mail). The objective of the current R21 application is to pre-validate a set of five CRC cancer antigen biomarkers through their multiplexed detection on a 3D paper-based microfluidic device in CRC patients as well as to test the possibility of using a self-regenerative photo-catalyst to amplify mass spectrometry (MS) signals for early CRC detection. The test is designed to be stable enabling storage under ambient conditions, a condition critical for successful remote sampling. The test is also rapid enough to enable point-ofcare testing on a portable mass spectrometer. Although the proposed detection strategy is based on immunoassay, the use of a photoredox catalyst to amplify MS signal is novel. Traditional immunoassay tests use colorimetric detection via enzyme amplification, necessitating both cold storage and analysis of the once-initiated colorimetric signal within a specified time to ensure the validity of the test. This research program will follow three specific aims: (1) using 356 CRC patient biorepository samples to validate the five selected biomarkers CEA, CA199, CA242, CA125, CA153 and to optimize their multiplexed detection via paper-based immunoassay, (2) investigation and selection of a photosystem for mass spectrometry signal amplification, and (3) using an independent set of patient samples collected in the field to validate proposed method through the development of a prototype 3D paper-based microfluidic device for CRC detection in whole blood samples. The project is innovative because it combines new levels of simplicity and practicality, modest levels of cost, and a centralized detection strategy, which will redefine the breadth of application and performance/cost ratio for accurate CRC detection in underserved communities. The proposed research is significant because it has potential to improve cancer care among all populations, irrespective of their race, geographic location, or income.