70
to specifically bind to a particular molecular structure is a key factor in molecular
recognition. Many of the current and future diagnostic tests are based on the use of
biological receptors as biochemical recognition elements, representing an important
economic impact. In 2016, the global market for in vitro diagnostics was worth $55
billion and is projected to reach $89,86 billion by the end of 2025 (Transparency
Research Market 2018).
Although biological receptors can show excellent recognition capabilities and
good selectivity, their low stability and high cost, limit their applications (Baggiani
et al. 2013). These problems pose serious challenges in the transfer of a large number of bio-diagnostic platforms to Point of Care Testing systems.
The mechanisms involved in molecular recognition provide valuable information about natural receptor-ligand interactions, which allows to mimic or even modulate cellular functions by chemical means. A promising approach to create artificial
receptors is molecular imprinting technology (MIT). This technique allows to create
three-dimensional (3D) polymer networks that present shape memory and functionality of a certain target molecule (ligand). It involves the copolymerization of the
mixture of monomers (functional(s) and crosslinker) in the presence of a template
molecule (ligand) and a solvent, known as porogen. After polymerization, the template is removed to obtain molecularly imprinted polymers (MIP) having complementary binding sites to the template.
MIPs are capable of selectively rebinding template molecules. Therefore, molecular imprinting technology is based on the molecular recognition of two molecules
(MIP-template) with a complementary ‘guest-host’ relationship. The molecular recognition mechanism in MIPs is reminiscent of natural interactions and constitutes
an induced molecular memory, which makes them capable of selective recognition.
In addition, they have certain advantages such as chemical stability, easy preparation, long shelf life, low cost, mechanical robustness and resistance to high pressure
and temperature. Furthermore, it does not require any preclinical development
involving animals. They can also behave like smart polymers that respond to single
or multiple stimuli such as biomolecules, electric and magnetic fields, ionic factors,
light intensity, pH, temperature, etc (Ge et al. 2013; Zarrintaj et al. 2019).
In this chapter, we present the most commonly used polymerization mechanisms
to synthesize MIPs with well-defined molecular structures, in several various formats and with improved binding properties. In order to determine the aspects
related to the binding behavior of imprinted polymers, the main methods used in
their morphological and physicochemical characterizations, as well as the binding
experiments performed with these materials, are also presented here. Although
much still remains to be done, the progress made in this field has undoubtedly contributed to the use of MIP as substitutes for antibodies and other natural receptors
in many applications. For example, it is impossible to ignore the great potential of
molecular imprinting to build smart materials potentially applicable in the healthcare market.
A. Gómez-Caballero et al.
to specifically bind to a particular molecular structure is a key factor in molecular
recognition. Many of the current and future diagnostic tests are based on the use of
biological receptors as biochemical recognition elements, representing an important
economic impact. In 2016, the global market for in vitro diagnostics was worth $55
billion and is projected to reach $89,86 billion by the end of 2025 (Transparency
Research Market 2018).
Although biological receptors can show excellent recognition capabilities and
good selectivity, their low stability and high cost, limit their applications (Baggiani
et al. 2013). These problems pose serious challenges in the transfer of a large number of bio-diagnostic platforms to Point of Care Testing systems.
The mechanisms involved in molecular recognition provide valuable information about natural receptor-ligand interactions, which allows to mimic or even modulate cellular functions by chemical means. A promising approach to create artificial
receptors is molecular imprinting technology (MIT). This technique allows to create
three-dimensional (3D) polymer networks that present shape memory and functionality of a certain target molecule (ligand). It involves the copolymerization of the
mixture of monomers (functional(s) and crosslinker) in the presence of a template
molecule (ligand) and a solvent, known as porogen. After polymerization, the template is removed to obtain molecularly imprinted polymers (MIP) having complementary binding sites to the template.
MIPs are capable of selectively rebinding template molecules. Therefore, molecular imprinting technology is based on the molecular recognition of two molecules
(MIP-template) with a complementary ‘guest-host’ relationship. The molecular recognition mechanism in MIPs is reminiscent of natural interactions and constitutes
an induced molecular memory, which makes them capable of selective recognition.
In addition, they have certain advantages such as chemical stability, easy preparation, long shelf life, low cost, mechanical robustness and resistance to high pressure
and temperature. Furthermore, it does not require any preclinical development
involving animals. They can also behave like smart polymers that respond to single
or multiple stimuli such as biomolecules, electric and magnetic fields, ionic factors,
light intensity, pH, temperature, etc (Ge et al. 2013; Zarrintaj et al. 2019).
In this chapter, we present the most commonly used polymerization mechanisms
to synthesize MIPs with well-defined molecular structures, in several various formats and with improved binding properties. In order to determine the aspects
related to the binding behavior of imprinted polymers, the main methods used in
their morphological and physicochemical characterizations, as well as the binding
experiments performed with these materials, are also presented here. Although
much still remains to be done, the progress made in this field has undoubtedly contributed to the use of MIP as substitutes for antibodies and other natural receptors
in many applications. For example, it is impossible to ignore the great potential of
molecular imprinting to build smart materials potentially applicable in the healthcare market.
A. Gómez-Caballero et al.