A method of homogeneously forming functionalized biocompatible oligomers includes the steps of dissolving a biocompatible oligomer in a solvent to form a solution, and admixing at least one π complex forming group to the solution, wherein the π complex forming group grafts to at least one location on the backbone of the oligomer to form a grafted oligomer. The oligomer is preferably oligochitosan and the solvent is preferably dimethylsulfoxide (DMSO). The degree of graft substitution can be at least 50%. The functionalized biocompatible oligomer can be used for drug detoxification through binding to a variety of target drugs.