title: Sensing protein antigen and microvesicle analytes using high-capacity biopolymer nano-carriers.
abstract: Lab-on-a-chip systems with molecular motor driven transport of analytes attached to cytoskeletal filament shuttles (actin filaments, microtubules) circumvent challenges with nanoscale liquid transport. However, the filaments have limited cargo-carrying capacity and limitations either in transportation speed (microtubules) or control over motility direction (actin). To overcome these constraints we here report incorporation of covalently attached antibodies into self-propelled actin bundles (nanocarriers) formed by cross-linking antibody conjugated actin filaments via fascin, a natural actin-bundling protein. We demonstrate high maximum antigen binding activity and propulsion by surface adsorbed myosin motors. Analyte transport capacity is tested using both protein antigens and microvesicles, a novel class of diagnostic markers. Increased incubation concentration with protein antigen in the 0.1-100 nM range (1 min) reduces the fraction of motile bundles and their velocity but maximum transportation capacity of >1 antigen per nm of bundle length is feasible. At sub-nanomolar protein analyte concentration, motility is very well preserved opening for orders of magnitude improved limit of detection using motor driven concentration on nanoscale sensors. Microvesicle-complexing to monoclonal antibodies on the nanocarriers compromises motility but nanocarrier aggregation via microvesicles shows unique potential in label-free detection with the aggregates themselves as non-toxic reporter elements.
authors.affiliation: Department of Chemistry and Biomedical Sciences, Linnaeus University, SE-391 82 Kalmar, Sweden. alf.mansson@lnu.se.
authors.forename: Saroj
authors.initials: S
authors.lastname: Kumar
authors.forename: Gloria
authors.initials: G
authors.lastname: Milani
authors.forename: Hideyo
authors.initials: H
authors.lastname: Takatsuki
authors.forename: Tobia
authors.initials: T
authors.lastname: Lana
authors.forename: Malin
authors.initials: M
authors.lastname: Persson
authors.forename: Chiara
authors.initials: C
authors.lastname: Frasson
authors.forename: Geertruy
authors.initials: G
authors.lastname: te Kronnie
authors.forename: Alf
authors.initials: A
authors.lastname: Månsson
mesh_terms: D000199:Actins / Q000737:chemistry*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D045744:Cell Line, Tumor; D055252:Cell-Derived Microparticles / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D008840:Microfilament Proteins / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D009038:Motion; D015879:Myosin Subfragments / Q000737:chemistry*; D011817:Rabbits; D012235:Rhodamines / Q000737:chemistry
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D005456:Fluorescent Dyes; D007074:Immunoglobulin G; D008840:Microfilament Proteins; D015879:Myosin Subfragments; D012235:Rhodamines; C020324:fascin; D017493:Leukocyte Common Antigens