Functional polysaccharide conjugates for the preparation of microarrays

A method for the immobilization of functional molecules on cellulose surfaces was developed. The irreversible deposition of the water-soluble polyelectrolyte carboxymethyl cellulose (CMC) on solid cellulose surfaces was used as a basis for this immobilization. CMC was modified using aminofluorescein (AMF) as a model compound for a functional molecule. The carbodiimide mediated coupling efficiency of AMF to CMC was studied in detail, and the functional conjugates were isolated. A quartz crystal microbalance with dissipation was employed to study the immobilization of the functionalized CMC onto cellulose model films in situ. The influence of the carbodiimide concentration, the degree of substitution, and the molecular weight of CMC on the immobilization process was investigated. Atomic force microscopy was used to characterize the changes in the surface morphology of the modified cellulose films. Finally, microspotted arrays of AMF-CMC conjugates were prepared with the knowledge obtained from the basic interaction studies. The successful deposition of AMF-CMC conjugates onto cellulose surfaces was proven by fluorescence microscopy. The conjugation of functional molecules to CMC and the subsequent deposition of these products on cellulose can be seen as a versatile method to immobilize these molecules for applications in the field of microarrays and other sensor surfaces. It offers the possibility to introduce new properties on a variety of cellulosic materials.