An Upgraded Protocol for the Silanisation of the Solid Phase for the Synthesis of Molecularly Imprinted Polymers

The introduction of solid-phase imprinting has had a significant impact in the molecular imprinting field, mainly due to its advantage of orienting the template immobilisation, affinity separation of nanoMIPs and faster production time. To date, more than 600 documents on Google Scholar involve solid-phase synthesis, mostly relying on silanes mediating template immobilisation on the solid phase. Organosilanes are the most explored functionalisation compounds due to their straightforward use and ability to promote the binding of organic molecules to inorganic substrates. However, they also suffer from well-known issues, such as lack of control in the layer's deposition and poor stability in water. Since the first introduction of solid-phase imprinting, few efforts have been made to overcome these limitations. The work presented in this research focuses on optimising the silane stability on glass beads (GBs) and iron oxide nanoparticles (IO-NPs), to subsequently function as solid phases for imprinting. The performance of three different aminosilanes were investigated; N-(6-aminohexyl) aminomethyltriethoxy silane (AHAMTES), 3-Aminopropyltriethoxysilane (APTES), and N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPTES), as well as studying the effect of dipodal silane bis(triethoxysilyl)ethane (BTSE). A stable solid phase was consequently achieved with 3% v/v AEAPTES and 2.4% BTSE, providing an upgraded protocol from Canfarotta et al. for the silanisation of the solid phase for molecular imprinting purposes.