DNA Aptamers\nThat Bind to Alginate Hydrogels

Hydrogels have become common in wound treatment because\nthey form\nvery stable and biocompatible environments that promote healing. However,\ndue to the highly porous hydrogel structure, any therapeutic added\nto these gels tends to diffuse quickly and impact delivery to the\ntarget site. Aptamers are short, single-stranded DNA or RNA sequences\nthat bind specifically to a target, so aptamers that bind to hydrogels\ncould serve as tags for therapeutics to prevent rapid diffusion and\nallow for extended delivery. An in vitro selection approach was developed\nto identify DNA aptamers for alginate hydrogels. Two DNA aptamers\nwere shown to bind hydrogels ranging from 0.5 to 2% alginate and could\nbe either encapsulated during gelation or introduced to preformed\ngels. Both aptamers also showed specificity for binding to alginate\ncompared to agarose. To demonstrate the functional aspect of the aptamers\nas tethers for other biomolecules, both aptamers were conjugated to\nBSA. Aptamer-conjugated BSA was retained longer in the hydrogel during\nweek-long diffusion studies both when encapsulated or introduced to\npreformed gels, which adds flexibility to how these aptamers can be\ndeployed in a clinical setting.