title: Microfluidic Cold-Finger Device for the Investigation of Ice-Binding Proteins.
abstract: Ice-binding proteins (IBPs) bind to ice crystals and control their structure, enlargement, and melting, thereby helping their host organisms to avoid injuries associated with ice growth. IBPs are useful in applications where ice growth control is necessary, such as cryopreservation, food storage, and anti-icing. The study of an IBP's mechanism of action is limited by the technological difficulties of in situ observations of molecules at the dynamic interface between ice and water. We describe herein a new, to our knowledge, apparatus designed to generate a controlled temperature gradient in a microfluidic chip, called a microfluidic cold finger (MCF). This device allows growth of a stable ice crystal that can be easily manipulated with or without IBPs in solution. Using the MCF, we show that the fluorescence signal of IBPs conjugated to green fluorescent protein is reduced upon freezing and recovers at melting. This finding strengthens the evidence for irreversible binding of IBPs to their ligand, ice. We also used the MCF to demonstrate the basal-plane affinity of several IBPs, including a recently described IBP from Rhagium inquisitor. Use of the MCF device, along with a temperature-controlled setup, provides a relatively simple and robust technique that can be widely used for further analysis of materials at the ice/water interface.
authors.affiliation: Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Lotem
authors.initials: L
authors.lastname: Haleva
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, Ohio; Department of Physics and Physical Sciences, Marshall University, Huntington, West Virginia.
authors.forename: Yeliz
authors.initials: Y
authors.lastname: Celik
authors.affiliation: Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Bar-Dolev
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, Ohio.
authors.forename: Natalya
authors.initials: N
authors.lastname: Pertaya-Braun
authors.affiliation: Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: Avigail
authors.initials: A
authors.lastname: Kaner
authors.affiliation: Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Davies
authors.affiliation: Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel; Department of Physics and Astronomy, Ohio University, Athens, Ohio. Electronic address: ido.braslavsky@mail.huji.ac.il.
authors.forename: Ido
authors.initials: I
authors.lastname: Braslavsky
mesh_terms: D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001517:Coleoptera; D004867:Equipment Design; D004926:Escherichia coli; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005615:Freezing; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007053:Ice; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D056656:Lab-On-A-Chip Devices; D007915:Lepidoptera; D053544:Marinomonas; D008856:Microscopy, Fluorescence; D010473:Perciformes; D013499:Surface Properties
chemical_list: D021301:Antifreeze Proteins; D001426:Bacterial Proteins; D029941:Fish Proteins; D007053:Ice; D019476:Insect Proteins; D049452:Green Fluorescent Proteins