Surface modification of poly(methyl methacrylate) used in the fabrication of microanalytical devices

We report here the chemical modification of poly(methyl methacrylate) (PMMA ) surfaces by their reaction with the monoanion of alpha,omega -diaminoalka nes (aminolysis reaction) to yield amine-terminated PMMA surfaces. It is fo und that the amine functionalities are tethered to the PMMA backbone throug h an alkane bridge to amide bonds forced during the aminolysis of the surfa ce ester functionalities. The distribution of the amine termini is quite un iform as judged by fluorescence micrographs. It is found that the electroos motic now in aminated PMMA microchannels is reversed when compared to that in unmodified channels. In addition, it is demonstrated that enzymes can be immobilized onto the amine-terminated PMMA surfaces and are effective in t he restriction digestion of dsDNAs. Finally, the availability of the surfac e amine groups is further demonstrated by their reaction with n-octadecane- 1-isocyanate to form PMMA surfaces terminated with well-ordered and highly crystalline octadecane chains.