title: Identification of malaria parasite-infected red blood cell surface aptamers by inertial microfluidic SELEX (I-SELEX).
abstract: Plasmodium falciparum malaria parasites invade and remodel human red blood cells (RBCs) by trafficking parasite-synthesized proteins to the RBC surface. While these proteins mediate interactions with host cells that contribute to disease pathogenesis, the infected RBC surface proteome remains poorly characterized. Here we use a novel strategy (I-SELEX) to discover high affinity aptamers that selectively recognize distinct epitopes uniquely present on parasite-infected RBCs. Based on inertial focusing in spiral microfluidic channels, I-SELEX enables stringent partitioning of cells (efficiency ≥ 10(6)) from unbound oligonucleotides at high volume throughput (~2 × 10(6) cells min(-1)). Using an RBC model displaying a single, non-native antigen and live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct, surface-displayed epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, var2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Birch
authors.affiliation: 1] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [2] BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, #04-13/14 Enterprise Wing, Singapore 138602, SINGAPORE.
authors.forename: Han Wei
authors.initials: HW
authors.lastname: Hou
authors.affiliation: 1] Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [2] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [3] BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, #04-13/14 Enterprise Wing, Singapore 138602, SINGAPORE.
authors.forename: Jongyoon
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Jacquin C
authors.initials: JC
authors.lastname: Niles
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000378:metabolism*; D004912:Erythrocytes / Q000469:parasitology*; D005453:Fluorescence; D006801:Humans; D008288:Malaria / Q000469:parasitology*; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D010271:Parasites / Q000502:physiology*; D015203:Reproducibility of Results; D052156:SELEX Aptamer Technique / Q000379:methods*; D013917:Thrombin / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D013917:Thrombin