Combining the Strengths of Mid-IR and Raman Spectroscopies on a Single Chip for Rapid Bedside Biomarker Diagnostics

There is a pressing need for diagnostic tools that can produce results quickly from patients' bedsides and in doctors' surgeries. Rapid, accurate results will allow rapid therapeutic decisions and save lives at reduced cost. In contrast, existing technologies require transfer of samples to centrally located laboratories equipped with sophisticated instruments, and highly skilled personnel. Bedside diagnostics using simplified, compact, versatile and efficient tools providing analysis results within a few minutes will therefore be a boon for many critically ill patients. In this project, we propose to develop two-in-one attenuated total reflection (ATR)/Raman chips that are compact, mass-producible, affordable, reliable, user-friendly and highly sensitive. The availability of such chips will enable the full potential and complementary nature of mid-IR molecular fingerprint and Raman spectroscopies to be exploited for bedside point-of-care diagnosis of critically ill patients who require rapid therapeutic decisions, meeting the ASSURED criteria set by the World Health Organisation (WHO). For example, provision of rapid diagnostic information will be invaluable for preterm infants (24-30 weeks gestation), for whom treatment decisions must be made as soon after birth as possible. Due to their lung immaturity, such infants are at high risk of suffering from neonatal Respiratory Distress Syndrome (nRDS), which has a high rates of mortality and morbidity with a major long-term economic burden on healthcare services. Using nRDS as an exemplar, we propose to develop a compact, versatile, rapid and easily operable bedside diagnostic tool for the next-generation bedside point-of-care to provide a predictive diagnostic test for nRDS to inform treatment options. The diagnostic device platform proposed here combines the complementary capabilities of fingerprint Mid-IR and Raman spectroscopies, each of which has been shown independently to be powerful biodiagnostic tool for specific biomarkers. In addition, we will employ a unique signal enhancement strategy that will simultaneously benefit both IR and Raman spectroscopies and significantly enhance their sensitivities. This new photonic technology and the portable diagnostic device proposed will not only underpin next-generation biomedical diagnostic applications but will also have major impacts in environmental monitoring and sensing including water pollution monitoring and trace toxic gas sensing.