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Probing the Interactions between α‐1, 4‐Mannobiose Molecules, using AFM
Author(s) -
Perera Komitige Hashanthi,
Basu Saswati,
Chandran Preethi
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1096.2
Subject(s) - chemistry , self assembled monolayer , mannose , drug delivery , covalent bond , monolayer , biochemistry , organic chemistry
Carbohydrate‐carbohydrate interactions (CCIs) have been recognized to govern a wide range of biological processes including species‐recognition, fertilization, embryogenesis, and cell development (1). The goals of our study are to investigate whether mannobiose moieties exhibit CCIs and to determine the solution conditions in which the interactions occur. Mannobiose moieties are disaccharides of mannose sugars. They coat the surfaces of pathogens and immune cells and are extensively involved in host‐pathogen interactions (2). The oligosaccharides are widely used in the design of drug‐delivery vehicles for targeting cells that express mannose receptors (e.g., dendritic cells) (2) and for reducing the cytotoxicity induced by the drug‐delivery vehicles (4). Therefore, the finding of CCIs between mannobiose moieties will impact the field of immunotherapy and the design of drug‐delivery vehicles. CCIs between α‐1, 4‐mannobiose moieties were measured using the force spectroscopy (FS) mode of an atomic force microscope (AFM). The mannobiose molecules were covalently attached to thiolated linkers and assembled as monolayers on gold‐coated mica and AFM tips. The mannobiose exposure on these functionalized surfaces was verified by its selective binding of lectin concanavalin‐A. The strength of CCIs between the mannobiosylated surfaces was determined as a function of the monovalent and divalent ion concentrations in the solution, and of the pH. Control experiments were designed to measure the interactions between the thiolated linkers. Our results indicate that there are self‐adhesive interactions between the mannobiosylated AFM surfaces. These interactions tend to be in the range of 200–800 pN, and predominantly occur as multiples of ~200pN. The addition of free mannobiose significantly diminishes the adhesive forces. We are currently investigating the effect of solution conditions on the magnitude of the interactions. The conclusion of our study is that mannobiosylated surfaces exhibit complex potential for interactions, which can be harnessed for the design of immunotherapies and of drug‐delivery vehicles. Support or Funding Information This material is based upon work supported by National Science Foundation under grant no. 1407891 awarded to Preethi Chandran and by a mini‐grant awarded to Preethi Chandran under NSF grant no. 1208880 (PI: Dr. Sonya Smith)