Advanced Clinical Diagnosis of Malaria Using a Simple Red-Emissive Smart Fluorescent Probe

Malaria, a potentially life-threatening disease caused by the mosquito-borne parasitic infection of human red blood cells, still accounts for over half a million deaths worldwide every year. Accurate early-stage diagnosis of malaria is indispensable for quick medical intervention and the avoidance of any potential complications leading to fatality. In this regard, DNA-specific fluorescent probes coupled with flow cytometry techniques emerged as a promising cost-effective diagnostic platform for highly sensitive rapid detection of malaria. However, ideal DNA-specific fluorescent probes that can be efficiently employed for both fluorescence microscopic studies as well as flow cytometric analysis to enable precise, high-quality clinical diagnosis of malaria are inadequate. In this context, we have reported a rationally designed hemicyanine dye MR-1 with blue absorption and red emission that can exhibit a turn-on fluorescence response upon effective binding with the AT-rich segments of dsDNA. The rationale behind designing the fluorescent probe MR-1 was well explained with the help of control compounds MR-2 and MR-3. The DNA-specific fluorescent probe MR-1 revealed excellent cell permeability and localized in the cellular nucleus of both live and fixed cells. A marked enhancement in fluorescence intensity was observed when malaria parasite-infected red blood cells were incubated with MR-1, and the detection limit was found to be ∼20/μL. Further, the flow cytometric analysis of clinical malaria parasite-infected red blood cells incubated with MR-1 not only demonstrated precise detection and classification of various malaria parasites but also smartly enabled the differentiation of malaria from Babesia-parasite infection with similar clinical symptoms.