Molecular imprinting in sol–gel materials: a focus on the interplay between matrix design and structural properties

Abstract

Molecular imprinting in sol–gel materials represents a versatile strategy for embedding selective recognition sites within inorganic and hybrid networks, enabling applications in sensing, separation, and catalysis. While traditionally approached as an extension of polymer-based imprinting, sol–gel systems introduce distinct physicochemical constraints arising from hydrolysis–condensation reactions, network densification, and limited structural adaptability. This review provides a critical analysis of the mechanistic foundations of sol–gel molecular imprinting, with particular emphasis on the interplay between matrix design, network evolution, and molecular recognition. By comparing inorganic, hybrid, and polymeric systems, the discussion highlights how rigidity, porosity, and hybridization govern binding thermodynamics, including enthalpy–entropy compensation and the contribution of elastic deformation to the binding free energy. A central challenge in the field is the frequent convolution of true cavity-driven recognition with morphology- and transport-related effects, which complicates the interpretation of analytical performance and limits the establishment of predictive design rules. Looking forward, progress will depend on the development of strategies that decouple molecular recognition from structural artifacts, enabling a transition from empirical optimization to quantitatively grounded materials design. In this context, the integration of sol–gel imprinting with controlled architectures and advanced transduction platforms offers significant opportunities for the development of robust and scalable functional materials.