Probing the limits of molecular imprinting: strategies with a template of limited size and functionality

Abstract

A series of polymers molecularly imprinted with the general anaesthetic propofol were synthesized using both semi- and non-covalent approaches. The polymers were evaluated with respect to template rebinding in both aqueous and organic media. In aqueous media, the observed propofol binding in these polymer systems was largely hydrophobic and non-specific in nature. In non-polar solvents such as hexane, electrostatic (hydrogen bonding) interactions dominate resulting in some selectivity. The implication of these results, in conjunction with those obtained using structures of similar size in other studies, is that propofol, a template possessing limited functionality and size, appears to define the lower limit for template size and degree of functionalization that can be used for the creation of ligand-selective recognition sites in molecularly imprinted polymers. Furthermore, studies with alternative ligands indicate that the steric crowding of a ligand's functionality to the polymer contributes to the extent of polymer-ligand recognition.

Covalent Imprinting and Covalent Rebinding of Benzyl Mercaptan: Towards a Facile Detection of Proteins

“…Therefore, controlled rebinding selectivity may be taken into account by covalent rebinding at room temparature with reasonably fast kinetics. The majority of covalent bonds have been used in imprinting that include boronic esters (Rajkumar et al 2007;Lin et al 2009), Schiff bases (Wulff, Heide, and Helfmeier 1986), carbonate esters (Petcu et al 2009), coordination bonds (Vidyasankar, Ru, and Arnold 1997), carbon-carbon double bonds (Kamplain and Bielawski 2006), cyclic additions (White et al 2001), olefins (Cantrill et al 2005), cyclic oligomers (Rowan, Reynolds, and Sanders 1999), trans-esterification (Fuchs et al 2003), trans-acetylation (Mukawa et al 2003), and disulfide bonds (Sellergren and Andersson 1990;Takeuchi et al 2006;Takeda et al 2009). …”