Molecularly Imprinted Polymers (Mips) for Bioanalytical Sensors: Strategies for Incorporation of Mips into Sensing Platforms

Review Article

Austin J Biosens & Bioelectron. 2015;1(3): 1011.

Molecularly Imprinted Polymers (Mips) for Bioanalytical Sensors: Strategies for Incorporation of Mips into Sensing Platforms

Marloes Peeters*

Queen Mary University of London, School of Biological and Chemical Sciences, UK

*Corresponding author: Marloes Peeters, Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, E1 4NS London, United Kingdom

Received: February 26, 2015; Accepted: April 21, 2015; Published: May 11, 2015


Molecularly Imprinted Polymers (MIPs) are synthetic receptors which have very beneficial properties compared to natural antibodies; they are robust, low-cost, have a high specificity, and can even detect their target molecules in complex matrices. MIPs for bioanalytical sensors are seemingly a perfect fit, but their use is limited due to the challenging incorporation of these receptors into sensing devices. In this review, various functionalization strategies will be discussed depending on the polymerization techniques that are employed and the morphology that is required for the sensor system. Furthermore, an outlook is given into using graphene based systems as sensor platforms since they could enhance the binding capacity of the MIPs.

Keywords: Molecularly Imprinted Polymers (MIPs); Biosensors; Polymerization techniques


ATRP: Atom-Transfer Radical-Polymerization; GO: Graphene Oxide; HPLC: High Performance Liquid Chromatography; MIPs: Molecularly Imprinted Polymers; NMP: Nitroxide Mediated Polymerization; PVC: Polyvinylchloride; PDMS: Polydimethylsiloxane; RAFT: Reversible Addition-Fragmentation Chain Transfer


Molecularly Imprinted Polymers are synthetic receptors containing recognition sites with a predetermined selectivity for various substances, ranging from ions, to neurotransmitters, proteins, and even whole cells [1-4]. Their specificty and selectivity towards their target molecule is similar to natural antibodies, but MIPs are superior in terms of their long-sterm stability, chemical inertness, and their ability to withstand extremes of pH and temperature [5-7]. In this review, we will focus on different functionalization strategies for MIPs targeted for small molecules since for the detection of larger molecules, in general surface imprinting techniques have the preference [8,9]. First, a two step process is discussed in which first the MIP particles are polymerized first and then attached to an electrode surface via a different procedure. Second, direct polymerization of the MIP particles is reviewed, which seems more straightforward but also significantly complicates the polymerization process. Finally, in recent years there has been a growing interest into graphene and graphene oxide and this material, becaue of its high surface area, could potentially improve the binding capacity of the imprints.

MIP functionalization onto sensor surface via a two step process

Bulk polymerization: micron sized particles: The most common method to produce MIPs to date is by bulk polymerization. While this might not seem the most elegant approach, it can be widely applied and offers a straight-forward synthesis [10,11]. Following this approach, all the components including monomers, template, crosslinker molecules, and initiator are dissolved into an appropriate porogen. The mixture is then polymerized by exposure to UV radiation or heat and a rigid block is obtained, which afterwards is processed by grinding and sieving [12]. The resulting material consists of micron sized particles which have irregular shapes with heterogenic parts due to the lack of control during the reaction [13]. The latter is not necessarily a drawback, because particles up to sizes of 25 micron can be directly packed into separation columns. Anderson et al. [14] demonstrated that a column equipped with MIP particles in the High-Performance Liquid Chromatography (HPLC) mode could not only separate similar structures of carbobenzoxy-aspartic acid, but could also discriminate between their enantiomeric forms. Huang et al. [15] followed a similar procedure and showed the separation of enantiomers and diastereomers of cinchona alkaloids by using a molecularly imprinted monolithic stationary phase. For sensing purposes, the functionalization strategy is less straightforward and also depends on the type of read-out technique that is employed.

Tan et al. [16] suspended MIP powders obtained by bulk polymerization into a mixture of the solvent tetrahydrofuran and Polyvinylchloride (PVC) powder. The resulting fluid was applied onto a Ag-electrode and rotated at a certain speed. After evaporation of the solvent in air, a MIP coating was formed which could detect concentrations of 25 nM L-nicotine in double-distilled water with microgravimetric read-out. A similar approach was followed Thoelen et al. [17], but instead of spincoating the MIP powers and a polymer together, first a thin layer (~200 nM) of a conjugated polymer was spincoated onto the electrodes. Then, the MIP particles were transferred onto the surface using a poly (dimethylsiloxane) PDMS stamp. Subsequently, the substrate is heated above the glass transition temperature of the polymer layer, allowing the MIP particles to sink into the layer. After cooling down, the particles are trapped into the matrix and can be used for sensing purposes (Figure 1). This technique can be compared to the conformation of an iceberg in the water, hence can be classified as the “iceberg model”.

Citation: Peeters M. Molecularly Imprinted Polymers (Mips) for Bioanalytical Sensors: Strategies for Incorporation of Mips into Sensing Platforms. Austin J Biosens & Bioelectron. 2015;1(3): 1011. ISSN :2473-0629