Janus silica nanosheets-based MMIPs platform for synergetic selective capture and fast separation of 2′-deoxyadenosine: Two different components segmented on the surface of one object

There is a pressing need to develop Janus-like magnetic molecularly imprinted polymers (J-SNs-MMIPs) nanoplatforms that integrate recognition elements and fast separation for specific adsorption and separation of 2′-deoxyadenosine (dA). In this work, the Janus silica nanosheet (J-SNs) with a hydrophobic surface (capped with 3-chloropropyl groups) and a hydrophilic surface (capped with amino-groups) was firstly fabricated by crushing Janus composite hollow spheres resulting from self-organized sol-gel process at amphiphilic emulsion interface. Subsequently, the imprinted polymers using dA as template molecule and synthesized 5-(2-Carbomethoxyvinyl)-2′-deoxyuridine (AcrU) as functional monomer were grafted onto the hydrophobic surface of J-SNs by activators regenerated electron transfer atom transfer radical polymerization (ARGET ATRP). Finally, carboxyl modified Fe3O4 particles were attached onto the hydrophilic surface of as-prepared J-SNs-MIPs via the condensation reaction between amino and carboxyl groups. The J-SNs-MMIPs displayed the ability to specifically recognize and fast separate dA, whereas no imprinting effect was observed for 2′-deoxyguanosine (dG) or deoxycytidine (dC) or 5′-monophosphate disodium salt (AMP). And the formed hydrogen bonds between complementary base of AcrU and adenine base on the dA enhance the affinity. Moreover, the equilibrium time was 70 min, and the maximum monolayer adsorption was calculated to be 61.22 μmol g−1 at 25 °C. By evaluating the selective recognition of dA from spiked human urine samples, the J-SNs-MMIPs could be used for selective separation and analysis of target dA in complex biological samples.