title: Droplet microfluidics platform for highly sensitive and quantitative detection of malaria-causing Plasmodium parasites based on enzyme activity measurement.
abstract: We present an attractive new system for the specific and sensitive detection of the malaria-causing Plasmodium parasites. The system relies on isothermal conversion of single DNA cleavage-ligation events catalyzed specifically by the Plasmodium enzyme topoisomerase I to micrometer-sized products detectable at the single-molecule level. Combined with a droplet microfluidics lab-on-a-chip platform, this design allowed for sensitive, specific, and quantitative detection of all human-malaria-causing Plasmodium species in single drops of unprocessed blood with a detection limit of less than one parasite/μL. Moreover, the setup allowed for detection of Plasmodium parasites in noninvasive saliva samples from infected patients. During recent years malaria transmission has declined worldwide, and with this the number of patients with low-parasite density has increased. Consequently, the need for accurate detection of even a few parasites is becoming increasingly important for the continued combat against the disease. We believe that the presented droplet microfluidics platform, which has a high potential for adaptation to point-of-care setups suitable for low-resource settings, may contribute significantly to meet this demand. Moreover, potential future adaptation of the presented setup for the detection of other microorganisms may form the basis for the development of a more generic platform for diagnosis, fresh water or food quality control, or other purposes within applied or basic science.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.
authors.forename: Sissel
authors.initials: S
authors.lastname: Juul
authors.forename: Christine J F
authors.initials: CJ
authors.lastname: Nielsen
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Labouriau
authors.forename: Amit
authors.initials: A
authors.lastname: Roy
authors.forename: Cinzia
authors.initials: C
authors.lastname: Tesauro
authors.forename: Pia W
authors.initials: PW
authors.lastname: Jensen
authors.forename: Charlotte
authors.initials: C
authors.lastname: Harmsen
authors.forename: Emil L
authors.initials: EL
authors.lastname: Kristoffersen
authors.forename: Ya-Ling
authors.initials: YL
authors.lastname: Chiu
authors.forename: Rikke
authors.initials: R
authors.lastname: Frøhlich
authors.forename: Paola
authors.initials: P
authors.lastname: Fiorani
authors.forename: Janet
authors.initials: J
authors.lastname: Cox-Singh
authors.forename: David
authors.initials: D
authors.lastname: Tordrup
authors.forename: Jørn
authors.initials: J
authors.lastname: Koch
authors.forename: Anne-Lise
authors.initials: AL
authors.lastname: Bienvenu
authors.forename: Alessandro
authors.initials: A
authors.lastname: Desideri
authors.forename: Stephane
authors.initials: S
authors.lastname: Picot
authors.forename: Eskild
authors.initials: E
authors.lastname: Petersen
authors.forename: Kam W
authors.initials: KW
authors.lastname: Leong
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Ho
authors.forename: Magnus
authors.initials: M
authors.lastname: Stougaard
authors.forename: Birgitta R
authors.initials: BR
authors.lastname: Knudsen
mesh_terms: D001483:Base Sequence; D057075:Enzyme Assays / Q000295:instrumentation*; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D013045:Species Specificity