Highly hydrophilic polyhedral oligomeric silsesquioxane (POSS)-containing aptamer-modified affinity hybrid monolith...

A novel polyhedral oligomeric silsesquioxane (POSS)-containing aptamer-modified hybrid affinity monolith with excellent hydrophilicity and unique architecture without Si-OH groups is presented herein, and the nonspecific adsorption caused by the hydrophobic nature of the monolithic column or polar interaction with silanol groups is minimized. Via a simple "one-pot" procedure, hydrophilic monomers were facilely polymerized with the POSS-methacryl substituted (POSS-MA) and aptamer; a highly hydrophilic nature was obtained and the lowest contact angle of 11° was achieved. By using ochratoxin A (OTA) as the model analyte, highly selective recognition of OTA in the mixture was achieved and the control of nonspecific interactions and the cross-reactivity of OTB and AFB1 were significantly improved. The recovery yield of OTB caused by nonspecific adsorption in the resultant monolith was only about 0.1% and remained steady even with the coexistence of a high OTB content (OTA : OTB = 1 : 50), which reached the best level to date and was obviously less than the 6.1% occurring in the hydrophobic POSS-containing control monolith, 8.3% in the POSS-PEI@AuNPs@aptamer affinity monolith and 18.7% in the silica-hybrid affinity monolith. When applied to wine and wheat samples, the nonspecific adsorption was significantly reduced and efficient discrimination of OTA was obtained with better results than that of the hydrophobic POSS-containing affinity column. This provides an attractive tool for minimizing the nonspecific adsorption for highly selective on-column recognition.