N-(3-Triethoxysilylpropyl)-4-(N′-maleimidylmethyl)cyclohexanamide (TPMC): A heterobifunctional reagent for immobilization of oligonucleotides on glass surface

A new heterobifunctional reagent, namely, N-(3-triethoxysilylpropyl)-4-(N′-maleimidylmethyl)cyclohexanamide (TPMC) was developed and its potentiality for fixing of thiol (-SH) modified oligonucleotides were tested. The covalent attachment of oligonucleotides with the reagent was achieved through its maleimide functionality at one end via stable thioether linkage while the other end bearing triethoxysilyl functionality has been utilized for coupling with the virgin glass surface with simplified methodologies. Immobilization of oligonucleotides was achieved by two alternating ways. The PATH-1 involves formation of conjugate of reagent and SH-modified oligonucleotides through thioether linkage and was subsequently immobilized on unmodified glass surface through triethoxysilyl group and alternatively, PATH-2 involves reaction of reagent first with unmodified glass surface to get maleimide functionality on the surface and then the SH-modified oligonucleotides were immobilized via thioether linkage. The specificity of immobilization was tested by hybridization study with complementary fluorescein labeled oligonucleotide strand.