Autofluorescent nanoparticles for the detection of malaria-infection indicator

Malaria plagues seriously in some tropical areas of the world, partly due to the lack of low-cost, sensitive diagnostic tools accessible. A simple way for fast monitoring malaria infection is to detect the elevated level of heme in the blood serum. Albumins are widely used in bioengineering due to their low-cost, good biocompatibility, and biodegradability. Herein we report that glutaraldehyde cross-linked bovine serum albumin (BSA) forms a suspension of novel fluorescent nanoparticles with an average size of ∼40 nm, exhibiting strong green autofluorescence. Autofluorescent nanoparticles were then developed as a novel optical probe for heme detection. Its application for ultrasensitive heme/hemin detection was demonstrated as the fluorescence intensity of the protein nanoparticles were quenched significantly upon the titration of hemin. The ultrasensitive sensing performance is ascribed to Photo-induced Electron Transfer (PET) as well as specific interaction between hemin and the fluorescent protein nanoparticles. The present study provides insights into the design of a cheap, simple and highly sensitive heme/hemin fluorescence biosensor which holds great potential for rapid and sensitive malaria diagnosis.