Template Removal in Molecular Imprinting: Principles, Strategies, and Challenges

The choice of an efficient template removal approach in the field of molecular imprinting is a daunting task as it varies from one template-monomer system to other. Optimum template removal conditions play a key role for the fate of resulting molecular imprints in any application. In this chapter, we present an overview of various template removal strategies employed in the synthesis of molecularly imprinted polymers (MIPs). Templates that are retained within the imprints reduce the number of available sites for analyte rebinding limiting the sensitivity of the MIPs substantially. Additionally, template leakage during analytical experiments may contribute to inaccurate measurements. Template removal is the least researched and often most expensive step in the imprinting process. The harsh conditions employed to enable complete template desorption in traditional extraction methods can damage the imprinted cavities or collapse them entirely. However, the development of neoteric extraction strategies holds promise for the optimization of the process. The integration of in silico studies with extraction strategies facilitates the rational selection of operational parameters. Herein, we discuss the principles of various template removal techniques as well as their respective merits and demerits along with emerging trends. Furthermore, the efficiencies of these techniques and their suitability for different template-polymer systems are analyzed. Finally, we present our views about the challenges, future perspectives, and opportunities of the integrated template removal techniques.