Development of a quantitative, portable, and automated fluorescent blue-ray device-based malaria diagnostic equipment with an on-disc SiO2 nanofiber filter

Takeki Yamamoto,Kaori Abe,Jun Ohashi,Yusuke Ido,Kazuaki Kajimoto,Takahiro Nogami,George Sonye,Kenji Nagatomi,Yasuyuki Sofue,Stephen Munga,Hiroaki Oka,Masatoshi Kataoka,Shouki Yatsushiro,James Kongere,Beatrice Awuor,Noboru Minakawa,Muneaki Hashimoto,Noriko Tamari,Takuya Hayashi,Toshihiro Mita

doi:10.1038/s41598-020-63615-2

Abstract

There is an urgent need to develop an automated malaria diagnostic system that can easily and rapidly detect malaria parasites and determine the proportion of malaria-infected erythrocytes in the clinical blood samples. In this study, we developed a quantitative, mobile, and fully automated malaria diagnostic system equipped with an on-disc SiO2 nanofiber filter and blue-ray devices. The filter removes the leukocytes and platelets from the blood samples, which interfere with the accurate detection of malaria by the blue-ray devices. We confirmed that the filter, which can be operated automatically by centrifugal force due to the rotation of the disc, achieved a high removal rate of leukocytes (99.7%) and platelets (90.2%) in just 30 s. The automated system exhibited a higher sensitivity (100%) and specificity (92.8%) for detecting Plasmodium falciparum from the blood of 274 asymptomatic individuals in Kenya when compared to the common rapid diagnosis test (sensitivity = 98.1% and specificity = 54.8%). This indicated that this system can be a potential alternative to conventional methods used at local health facilities, which lack basic infrastructure.

Highlights

There is an urgent need to develop an automated malaria diagnostic system that can and rapidly detect malaria parasites and determine the proportion of malaria-infected erythrocytes in the clinical blood samples
We confirmed that the number of leukocytes remaining on the detection area after SiO2 nanofiber filtration was low in 274 Kenyan blood samples (Fig. 2, Table 2). These results indicated that the developed filtration system can remove most of the leukocytes from the blood samples obtained from the individuals living in malaria-endemic region
We evaluated the degree of correlation between the percentage parasitaemia obtained by our diagnostic system and that obtained by microscopy in 53 malaria parasite-positive samples (Supplementary Table S4)

Summary

Introduction

There is an urgent need to develop an automated malaria diagnostic system that can and rapidly detect malaria parasites and determine the proportion of malaria-infected erythrocytes in the clinical blood samples. We developed a quantitative, mobile, and fully automated malaria diagnostic system equipped with an on-disc SiO2 nanofiber filter and blue-ray devices. The filter removes the leukocytes and platelets from the blood samples, which interfere with the accurate detection of malaria by the blue-ray devices. The patient blood samples contain leukocytes and platelets, which potentially produce fluorescent noises These noises interfere with the accurate detection of malaria. We first developed a SiO2 nanofiber filter device and incorporated it into the scan disc, which can be operated automatically without the need for centrifugation This modification enabled the conversion of the current system into a fully automated malaria diagnosis equipment. We validated the applicability of the newly developed equipment for the diagnosis of P. falciparum in individuals from the malaria-endemic region of Kenya

Methods

Results

Conclusion