Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles

Abstract

Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model.

Fig 1. Urine from P. vivax negative volunteers turned AuNPs blue due to lack of targeted MSP10 DNA while positive P. vivax urine was able to form DS DNA and stabilized AuNPs to stay red in color.

Fig 2. The newly formed MSP10 double stranded DNA in urine was able to stabilize AuNPs to stay red in color.

P. vivax negative urine turned AuNPs’ color to blue which was detected by Spectrophotometer as color switches from red at 520 wavelength (P. vivax positive) into purple-blue at 610 wavelength (P. Vivax negative).

Fig 3. N-Terminal MSP10 oligonucleotide has higher sensitivity, similar specificity and lower cross-reactivity in comparison to C-Terminal segment of MSP10 DNA in detecting P. vivax in urine using AuNPs.