title: Biomarker-mediated disruption of coffee-ring formation as a low resource diagnostic indicator.
abstract: The ring pattern resulting from the unique microfluidics in an evaporating coffee drop is a well-studied mass transport phenomenon generating interest in the research community mostly from a mechanistic perspective. In this report, we describe how biomarker-induced particle-particle assemblies, magnetic separation, and evaporation-driven ring formation can be combined for simple pathogen detection. In this assay design, the presence of biomarkers causes self-assembly of a magnetic nanoparticle and a fluorescently labeled micrometer-sized particle. A small spherical magnet under the center of the drop prevents these assemblies from migrating to the drop's edge while a nonreactive control particle flows to the edge forming a ring pattern. Thus the presence or absence of biomarker results in distinctly different distributions of particles in the dried drop. Proof-of-principle studies using poly-L-histidine, a peptide mimic of the malaria biomarker pfHRPII, show that the predicted particle distributions occur with a limit of detection of approximately 200-300 nM.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University VU Station B 351631 Nashville, Tennessee 37235, USA.
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Trantum
authors.forename: David W
authors.initials: DW
authors.lastname: Wright
authors.forename: Frederick R
authors.initials: FR
authors.lastname: Haselton
mesh_terms: D000953:Antigens, Protozoan / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis / Q000737:chemistry; D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism; D019963:Clinical Chemistry Tests / Q000295:instrumentation*; D005456:Fluorescent Dyes / Q000737:chemistry; D006639:Histidine / Q000737:chemistry / Q000378:metabolism; D057230:Limit of Detection; D059346:Magnets / Q000737:chemistry; D008288:Malaria / Q000175:diagnosis / Q000378:metabolism; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry; D015800:Protozoan Proteins / Q000378:metabolism; D014835:Volatilization
chemical_list: D000953:Antigens, Protozoan; D015415:Biomarkers; D005456:Fluorescent Dyes; C514457:HRP-2 antigen, Plasmodium falciparum; D015800:Protozoan Proteins; C033223:polyhistidine; D006639:Histidine