Molecularly Imprinted Polymers Microparticles Research Articles

Efficient Optosensing of Hippuric Acid in the Undiluted Human Urine with Hydrophilic "Turn-On"-Type Fluorescent Hollow Molecularly Imprinted Polymer Microparticles.

The development of complex biological sample-compatible fluorescent molecularly imprinted polymers (MIPs) with improved performances is highly important for their real-world bioanalytical and biomedical applications. Herein, we report on the first hydrophilic "turn-on"-type fluorescent hollow MIP microparticles capable of directly, highly selectively, and rapidly optosensing hippuric acid (HA) in the undiluted human urine samples. These fluorescent hollow MIP microparticles were readily obtained through first the synthesis of core-shell-corona-structured nitrobenzoxadiazole (NBD)-labeled hydrophilic fluorescent MIP microspheres by performing one-pot surface-initiated atom transfer radical polymerization on the preformed "living" silica particles and subsequent removal of their silica core via hydrofluoric acid etching. They showed "turn-on" fluorescence and high optosensing selectivity and sensitivity toward HA in the artificial urine (the limit of detection = 0.097 μM) as well as outstanding photostability and reusability. Particularly, they exhibited much more stable aqueous dispersion ability, significantly faster optosensing kinetics, and higher optosensing sensitivity than their solid counterparts. They were also directly used for quantifying HA in the undiluted human urine with good recoveries (96.0%-102.0%) and high accuracy (RSD ≤ 4.0%), even in the presence of several analogues of HA. Such fluorescent hollow MIP microparticles hold much promise for rapid and accurate HA detection in the clinical diagnostic field.

Preparation of complex biological sample-compatible "turn-on"-type ratiometric fluorescent molecularly imprinted polymer microspheres via one-pot surface-initiated ATRP.

The efficient preparation of ratiometric fluorescent molecularly imprinted polymer (MIP) microspheres that can directly and selectively optosense a herbicide (i.e., 2,4-dichlorophenoxyacetic acid, 2,4-D) in undiluted pure milk is described. Thedual fluorescent MIP microparticles were readily obtained through grafting a green 4-nitrobenzo[c][1,2,5]oxadiazole (NBD)-labeled 2,4-D-MIP layer with hydrophilic polymer brushes onto the preformed uniform "living" red CdTe quantum dot (QD)-labeled SiO2 microspheres via one-pot surface-initiated atom transfer radical polymerization (SI-ATRP) in the presence of a polyethylene glycol macro-ATRP initiator. They proved to be highly promising "turn-on"-type fluorescent chemosensors with red CdTe QD (the maximum emission wavelength λe,max around 710nm) and green NBD (λe,max around 515nm) as the reference fluorophore and "turn-on"-type responsive fluorophore, respectively. The sensors showed excellent photostability and reusability, high 2,4-D selectivity and sensitivity (the limit of detection = 0.12μM), and direct visual detection ability (a fluorescent color change occurs from red to blue-green with the concentration of 2,4-D increasing from 0 to 100μM) in pure bovine milk. The sensorswere used for 2,4-D detection with high recoveries (96.0-104.0%) and accuracy (RSD ≤ 4.0%) in pure goat milk at three spiking levels of both 2,4-D and its mixtures with several analogues. This new strategy lays the foundation for efficiently developing diverse complex biological sample-compatible ratiometric fluorescent MIPs highly useful for real-world bioanalyses and diagnostics.

Molecularly Imprinted Polymer for a Smart Dispersive Micro-Solid Phase Extraction Technique for Assessing Trace Level Aflatoxins in Cultured Fish.

Molecularly imprinted technology (MIT) consists of preparing materials exhibiting specific recognition cavities to selective mimic the target analytes. The prepared materials promote selective interactions with the targets and avoid interactions of concomitants from complex food, biological, clinical, and environmental matrices. This chapter provides information on a recent development of a vortex-assisted micro-solid phase extraction using a molecularly imprinted polymer (MIP) as an adsorbent for aflatoxins (AFs) determination in cultured fish. MIP particles were synthesized by precipitation polymerization using 5,7-dimethoxycoumarin as a dummy template, methacrylic acid as a functional monomer, divinylbenzene as a cross-linker, and 2,2-azobisisobutyronitrile as an initiator. Polymerization following the precipitation method guarantees homogeneous particle size distribution and the integrity of the imprinted cavities. The MIP microparticles were found to have 5μm in diameter and a spherical shape. Important parameters such as sample extract pH, adsorption stirring speed and time, desorption stirring speed and time, elution solvent composition and volume, and polymer mass, were fully optimized. The pre-concentration method allows therefore the assessment of four major AFs (B1, B2, G1, and G2) present in cultured fish at very low levels, with pre-concentration factors from 15 to 50 depending of the volume of extract used for performing the dispersive micro-solid phase extraction (D-μ-SPE).

Rational development of molecular imprinted carbon paste electrode for Furazolidone detection: theoretical and experimental approach

Determination of antibiotics in environmental waters is an important global issue. Although furazolidone (FZD) was banned from use in food-producing animals, owing to its mutagenic and carcinogenic effects, this antibiotic has been illegally used across the world and its presence in environment have being noted.In this work, the first selective molecularly imprinted polymer (MIP) was developed for electrochemical detection of FZD. It was constructed based on the modification of the traditional carbon paste electrode (CPE) with MIP microparticles, followed by introduction of multi-walled carbon nanotubes (MWCNTs). Quantum mechanical (QM) calculations and molecular dynamics (MD) simulations were performed to allow rational selection of an appropriate functional monomer and to simulate the best pre-polymerisation conditions, respectively. The MIP were synthetized by polymerization using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as monomer and FZD as template molecule. The MIP microparticles were then incorporated on CPE-MWCNTs and the electrochemical analysis of FZD were evaluated by differential pulse voltammetry (DPV). After optimisation of experimental conditions, the MIP-CPE-MWCNTs sensor exhibited a good linear response over the concentration range of 0.01 μM to 1 μM with a correlation coefficient of 0.9995. The limit of detection (LOD) was found to be 0.03 μM (S/N = 3). Due to high imprinting efficiency the sensor displayed selectivity to recognise FZD molecules and it was successfully applied in water samples where excellent recovery values (over 90 %) were obtained. The proposed sensor provides an efficient and promising sustainable strategy for monitorisation of FZD in environmental waters.

The influence of cross-linking agent onto adsorption properties, release behavior and cytotoxicity of doxorubicin-imprinted microparticles

Molecularly imprinted polymers (MIPs) are synthetic polymers that possess cavities selective towards their molecular templates and have found many applications in separation science, drug delivery, and catalysis. Here, we report the synthesis of doxorubicin-imprinted microparticles cross-linked with two different compounds (ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate) and examination of their physicochemical properties. During the synthesis methacrylic acid was used as functional monomer and 2-hydroxyethyl methacrylate was added into polymerization mixture to increase hydrophilicity of the obtained materials and therefore improve interactions with aqueous release medium. The influence of initial concentration and contact time onto doxorubicin adsorption by obtained MIPs microparticles have been investigated. The microparticles obtained using ethylene glycol dimethacrylate as a cross-linker showed 3 times higher adsorption properties towards doxorubicin, than the ones obtained using trimethylolpropane trimethacrylate cross-linker. The release kinetics of doxorubicin from drug-loaded MIPs microparticles has been proven to be dependent upon cross-linker used and pH of the release medium. For drug-loaded MIPs microparticles obtained using both cross-linkers the IC50 values measured for cancer cell were comparable to the ones measured for pure doxorubicin, whereas the cytotoxicity towards normal HDF cell lines was lower.

Application of paclitaxel-imprinted microparticles obtained using two different cross-linkers for prolonged drug delivery

Molecularly imprinted polymers (MIPs) are artificial materials processed to have cavities in the polymer structure which are capable of forming selective interactions with their molecular templates. Here, we report the synthesis of paclitaxel-imprinted microparticles and their application in prolonged drug delivery. Methacrylic acid was used as a functional monomer and 2-hydroxyethyl methacrylate was added to increase hydrophilicity of the obtained MIPs and therefore to improve compatibility with water solutions. The effect of two different cross-linkers, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate, on the final properties of obtained MIPs microspheres was examined. The influence of initial paclitaxel concentration as well as its contact time with MIPs microparticles on adsorption process was investigated. The release kinetics of paclitaxel from drug-loaded MIPs was found to be significantly depend upon the type of cross-linker used as well as the pH of the release medium. The highest cumulative release was observed at pH 7.4 for MIPs obtained using trimethylolpropane trimethacrylate as a cross-linker, reaching 85% in 50 h. The MIPs obtained using this cross-linker were characterized by IC50 comparable to the ones measured for pure paclitaxel. These results clearly indicate that the obtained MIPs microparticles have a large potential for prolonged drug delivery.

A novel capacitive sensor based on molecularly imprinted nanoparticles as recognition elements

Molecularly Imprinted Polymers (MIPs) are synthetic receptors capable of selective binding to their target (template) molecules and, hence, are used as recognition elements in assays and sensors as a replacement for relatively unstable enzymes and antibodies. Herein, we describe a manufacturing-friendly protocol for integration of MIP nanoparticles (nanoMIPs) with a (label-free) capacitive sensor. The nanoMIPs were produced by solid-phase synthesis for two templates with different sizes and properties, including a small molecule tetrahydrocannabinol (THC) and a protein (trypsin). NanoMIPs were deposited on the surface of the sensor and the change in capacitance (ΔC) upon binding of the target was measured. The significant improvement in the selectivity and limit of detection (one order of magnitude compared to previously used MIP microparticles) can be attributed to their increased surface-to-volume ratio and higher specificity of the nanoMIPs produced by the solid-phase method. The methodology described is also compatible with common sensor fabrication approaches, as opposed to methods involving in situ MIP polymerisation. The proposed sensor shows high selectivity, fast sensor response (45 min including injection, regeneration and re-equilibration with running buffer), and straightforward data analysis, which makes it viable for label-free monitoring in real-time. The set of targets assessed in this manuscript shows the general applicability of the biosensor platform.

Synthesis and characterization of paclitaxel-imprinted microparticles for controlled release of an anticancer drug

In this study, novel molecularly imprinted polymer (MIP) microparticles containing methacryl polyhedral oligomeric silsesquioxane (M-POSS) were synthesized through the RAFT precipitation polymerization (RAFTPP) method using paclitaxel (PTX) as the templates. During the course of this investigation, methacrylic acid (MAA) was used as the functional monomer, while ethylene glycol dimethacrylate (EGDMA) was utilized as a cross-linker. The effects of different molar ratios of M-POSS on the microparticles were characterized. The obtained MIP microparticles were confirmed by FT-IR and TGA-DSC. The results of SEM showed regular spherical-shaped MIP microparticles with diameters around 170–490 nm. The PTX loading quantity was closely correlated with the content of M-POSS, and the MIP microparticles showed a satisfactory affinity to PTX with high drug loading (17.1%) and encapsulation efficiency (85.5%). Moreover, these MIP microparticles were sensitive to pH, and consequently the release rates of PTX at pH 5 were much faster than those at pH 7 due to the acid cleavage of the hydrogen bonds. In addition, the results from release experiments of the MIP microparticles showed a very slow and controlled release of PTX, which heralded promising potential as a carrier for PTX delivery in cancer therapy.

Direct and Highly Selective Drug Optosensing in Real, Undiluted Biological Samples with Quantum-Dot-Labeled Hydrophilic Molecularly Imprinted Polymer Microparticles.

Quantum-dot (QD)-labeled hydrophilic molecularly imprinted polymer (MIP) microparticles were prepared for direct and highly selective optosensing of an antibiotic drug (i.e., tetracycline (Tc)) in pure bovine/goat milks and bovine/porcine serums. "Living" CdTe QD-SiO2 composite microparticles with alkyl bromide groups on their surfaces were first obtained via the one-pot sol-gel reaction, and they were subsequently grafted with a Tc-imprinted polymer layer and poly(glyceryl monomethacrylate) brushes via the successive surface-initiated atom transfer radical polymerizations. The resulting MIP microparticles with QD labeling and hydrophilic polymer brushes could function properly in biological samples and showed obvious template-binding-induced fluorescence quenching, which make them a useful fluorescent chemosensor with limits of detection down to 0.14 μM in complex biological media. Moreover, a facile and effective approach was developed based on a newly derived equation to eliminate the false positives of the fluorescent chemosensor and provide it with wider linear detection concentration ranges in comparison with those obtained using the generally adopted Stern-Volmer equation. Furthermore, the fluorescent MIP chemosensor was also successfully applied for directly, sensitively, selectively, and accurately quantifying Tc in biological media, and the average recoveries were in the range of 95%∼105% even when several other drugs and the fluorescently interfering chlortetracycline were present in the samples.

Hydrophilic Hollow Molecularly Imprinted Polymer Microparticles with Photo- and Thermoresponsive Template Binding and Release Properties in Aqueous Media.

A facile, general, and efficient approach to prepare hydrophilic hollow molecularly imprinted polymer (MIP) microparticles with photo- and thermoresponsive template binding and release behaviors in aqueous media is described, which includes the preparation of uniform "living" silica submicrospheres bearing surface atom transfer radical polymerization (ATRP)-initiating groups (i.e., alkyl halide groups) via a one-pot sol-gel method, their subsequent grafting of azobenzene (azo)-containing MIP shell and poly(N-isopropylacrylamide)-block-poly(2-hydroxyethyl methacrylate) (PNIPAAm-b-PHEMA) brushes via successive surface-initiated ATRP, and final removal of the silica core. The successful synthesis of such hydrophilic hollow MIP microparticles was confirmed with SEM, FT-IR, water dispersion stability, and static contact angle studies. They proved to show apparently higher template binding capacities than the corresponding solid ones and obvious photo- and thermoresponsive template binding properties in aqueous solutions. Moreover, their pronounced light- and temperature-controlled template release in aqueous media was also demonstrated. In particular, the introduction of PNIPAAm-b-PHEMA brushes onto hollow MIP microparticles imparted them with high surface hydrophilicity both below and above the lower critical solution temperature of PNIPAAm, which paves the way for their applications in such areas as controlled drug/chemical delivery and smart bioanalysis.

Investigation of a self-assembling microgel containing an (S)-propranolol molecularly imprinted polymer in a native tissue microenvironment: Part I. Preparation and characterization

In this study, we have developed a molecularly imprinted polymer (MIP) selective for (S)-propranolol that was encapsulated within an assembled gel, and allowed for an induced interaction in a live tissue environment. The development of the MIP microparticles having assembled nanoparticles with separated domains at their outer shell involved an assessment of the selectivity of the template and the morphology of its surface, using single and mixed crosslinking agents. The MIPs resulted in differential rebinding of the template, governed by different crosslinked architectures of the resulting polymer. The strength of the interaction of that shape molecule with the adaptable properties in the pore-wall of recognition site, especially an MIP that was prepared using a mixed crosslinker on lining silicone membrane, influenced high enantioselectivity in the gel. A different configuration response of the MIP embedded responsive gel enabled drug shaping, and affected generating the intrinsic recognition for an increase of the macromolecular proximity and dynamic interactions in the excised skin. Overall, the MIPs in a self-assembled microgel may show a potential for the study of integrated biological systems, with pharmaceutical and even therapeutic applications.

Synthesis and Evaluation of Uniformly Sized Synephrine-Imprinted Microparticles Prepared by Precipitation Polymerization

Uniformly sized synephrine molecularly imprinted polymer (MIP) microparticles were prepared via precipitation polymerization. The presence of the template, the amount of monomer, crosslinker, and porogenic solvent could affect the size distribution and morphology of the polymers. The pseudo-second-order kinetic model could provide a better correlation for the adsorption than the pseudo-first-order model. The intraparticle diffusion study showed that the sorption involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium data better fit the Freundlich model than the Langmuir model. The Scatchard plot of MIPs revealed MIPs had two groups of sites with different affinities. Subsequent recognition selectivity experiments demonstrated preferential structural selectivity for synephrine with respect to other structurally similar compounds (i.e., octopamine and tyramine). Compared with the bulk MIP of SYN, the SYN MIP microparticles in this work had higher adsorption selectivity and capacity due to their smaller particle sizes; moreover, the precipitation polymerization was time-saving due to not using a crash-and-sieve process.

Molecularly imprinted nanoparticles with nontailing peaks in capillary electrochromatography

The combination of microparticles of molecularly imprinted polymers (MIPs) with partial filling capillary electrochromatography (CEC) has previously been demonstrated for the enantiomer separation. In this paper, precipitation polymerization was used to prepare d-zopiclone imprinted nanoparticles (50–80nm) by a strategy of the dilution of pre-polymerization mixtures. The influence of some important parameters on the preparation of MIPs nanoparticles, including template to monomer ratio, type and amount of cross-linking monomer, and functional monomer composition ratio were investigated. In addition, the effect of separation condition, e.g., organic modifier content, pH value and salt concentration of buffer, on the electrochromatographic behavior of the MIP nanoparticles were studied. In spite of lower selectivity factor (1.11), high column performance (theoretical plates 41,400) of template was obtained and the resolution of enantiomers separation was 4.75 under the optimized conditions. Compared to the previously reported MIP microparticles, the MIP nanoparticles showed good peak symmetry and an ability of high speed separation (<15min) in CEC mode.

MIP-based biomimetic sensor for the electronic detection of serotonin in human blood plasma

a b s t r a c t Serotonin is an important signaling molecule in the human body. The detection of serotonin is commonly performed by high performance liquid chromatography (HPLC), which is costly and time consuming due to extensive sample preparation. We will show that these problems can be overcome by using molec- ularly imprinted polymers (MIPs) as synthetic receptors in combination with impedance spectroscopy as readout technique. The MIPs were prepared with several blends of the underlying monomers and the best performing MIP material was selected by optical batch-rebinding experiments. MIP microparticles were then integrated in an impedimetric sensor cell and dose-response curves were measured in PBS buffer and in non-diluted blood plasma. The sensor provides reliable data in the physiologically relevant concentration regime as an independent validation by HPLC measurements demonstrates. Finally, we show that the impedimetric response upon serotonin binding can be attributed to a capacitive effect at the interface between the MIP particles and the plasma.

CEC separation of ofloxacin enantiomers using imprinted microparticles prepared in molecular crowding conditions

Molecular crowding is a new concept to obtain molecularly imprinted polymers (MIPs) with greater capacity and selectivity, which could shift the equilibrium of a print molecule reacting with functional monomers in the direction of complex formation side. In this work, molecular crowding agent was first applied to the preparation of MIPs microparticles by precipitation polymerization. A new system of molecular crowding surrounding was developed, composed of polystyrene and tetrahydrofuran, in the presence of the template (S)-ofloxacin. Partial filling capillary electrochromatography (CEC) was utilized to evaluate imprinting effect of the resulting microparticles by chiral separations of ofloxacin. Some important parameters in the preparation, i.e. template to monomer ratio, influence of cross-linking monomers and functional monomer composition on the CEC separation of MIP microparticles were investigated. Baseline separation of ofloxacin (R(s) =1.53) was obtained under optimized conditions and the highest theory plate of the later eluent (S)-ofloxacin was 5400. The textural and morphological parameters for imprinted particles, such as Brunauer-Emmett-Teller surface areas, pore volumes and pore size distributions have also been determined. Compared to the MIP microparticle prepared by conventional precipitation polymerization, the (S)-ofloxacin-imprinted particles formed under molecular crowding conditions showed higher selectivity (α=1.09) and separation efficiency (<25 min) in the CEC mode.

Optimization of Molecularly Imprinted Polymers of Serotonin for Biomaterial Applications

We prepared molecularly imprinted polymers (MIPs) of serotonin (5-hydroxytryptamine or 5-HT), a neurotransmitter and mood modulator, using a combination of neutral (methacrylamide or acrylamide) and positively charged (methacrylic acid) functional monomers. Water, PBS, acidified methanol and sodium dodecyl sulfate were compared as rinsing solvents for the removal of serotonin from the MIPs. Methacrylamide MIPs rinsed in acidified methanol (92% serotonin removal) produced the highest imprinting factor (3.1) in equilibrium batch rebinding experiments using a combination of 2% water and 98% MeCN as the rebinding solvent. For the first time, these MIPs were assessed for cytocompatibility using mouse mesencephalon neural progenitor cells (NPC) and NIH 3T3 fibroblasts. Although MIP particles decreased NPC viability to <70%, MIP particles did not significantly reduce fibroblast viability when incorporated into a hyaluronic acid biomaterial. MIP microparticles were incorporated into a cross-linked hyaluronic acid biomaterial to present one way in which molecularly imprinted polymers may be used in vivo in future biomaterials or biosensors applications.

Detection of Nitroaromatic Explosives Using a Fluorescent-Labeled Imprinted Polymer

Optical sensors have proven to be a useful method in identifying explosive devices by recognizing vapors of explosive compounds that become airborne and emanate from the device. To detect high explosive compounds such as TNT, a molecularly imprinted polymer (MIP) sensing mechanism was developed. This mechanism consists of MIP microparticles prepared using methacrylic acid as the functional monomer. The MIP microparticles are then combined with fluorescent quantum dots via a simple cross-linking procedure. The result is a highly robust optical sensing scheme that is capable of functioning in an array of environmental conditions. To study the sensing mechanisms's ability to detect nitroaromatic analytes, the fluorescent-labeled MIP particles were tested for their performance in detecting aqueous 2,4-dinitrotoluene (DNT), a nitroaromatic molecule very similar to TNT, as well as TNT itself. These preliminary data indicate that the system is capable of detecting nitroaromatic compounds in solution with high sensitivity, achieving lower limits of detection of 30.1 and 40.7 microM for DNT and TNT, respectively. The detection mechanism also acted rapidly, with response times as low as 1 min for TNT. Due to the results of this study, it can be concluded that the fluorescent-labeled MIP system is a feasible method for detecting high explosives, with the potential for future use in detecting vapors from explosive devices.

On the synthesis of peptide imprinted polymers by a combined suspension—Epitope polymerization method

In the past, molecularly imprinted polymers (MIPs), prepared by free-radical bulk polymerization, have been used for the selective recognition of small biomolecules (i.e., amino acids and amino acid derivatives). Presently, there is a need for the synthesis of MIPs capable of recognizing larger biomolecules (i.e., peptides and proteins). Moreover, it is highly desirable the production of MIP microparticles with well-defined morphological characteristics (e.g., particle size distribution, porosity, etc.) via particulate polymerization techniques. In the present study, the synthesis of molecularly imprinted microparticles, produced via the suspension and inverse suspension polymerization methods, using the “epitope approach”, is reported. The hydrophobic (i.e., Boc-Trp-Trp-Trp) or hydrophilic (i.e., His-Phe) oligo-peptides were employed as template molecules. The potential of the combined suspension polymerization method with the “epitope approach” for the production of MIP microparticles is demonstrated, as well as the specificity and selectivity characteristics of the MIP microparticles towards hydrophobic and hydrophilic oligo-peptides. The proposed method appears to be a very promising and efficient technique for separation of proteins.

Boc- l-tryptophan imprinted polymeric microparticles for bioanalytical applications

Molecularly imprinted polymer (MIP) microparticles with good chromatographic characteristics were synthesized via the suspension polymerization process in a single preparative step. Initially, the effects of process parameters (i.e., porogen concentration, polymerization temperature, types and concentrations of functional monomer and cross-linker) on the particle size distribution and particle morphology were experimentally investigated. Subsequently, various MIP microparticles were synthesized in the presence of an amino acid derivative (i.e., boc- l-tryptophan), acting as template molecule. Batch-wise guest binding experiments were then performed to determine the rebinding capacity of the synthesized MIP microparticles towards the template molecule. Competitive binding experiments were also carried out with boc- d-tryptophan (i.e., the enantiomer of boc- l-tryptophan) to assess the selectivity of the imprinted polymer microparticles towards the two enantiomers. Finally, a quantitative description of the experimentally measured rebinding isotherms was obtained using the well-known Freundlich–Langmuir models. The present results clearly demonstrate the potential application of the synthesized MIP microparticles for bioanalytical separation of peptides and proteins since the amino acid templates employed in this study are the building units of larger biomolecules.

Functional Patternings Fabricated using Molecularly Imprinted Polymer; Molecular Recognitions for Chemical Detection

ABSTRACTWe present functional patterns fabricated using functional polymers. The functional polymer is MIP (molecularly imprinted polymer) system, which can be produced through “molecular imprinting” to create “synthetic receptor or binding sites” for bio/chemical detection technology. Those binding sites have specific molecular recognition functions for targeting organic or bio molecules. MIP's patterns in the micro-scale were fabricated for chemical sensors, diagonostic bio-sensors, and for drug delivery systems. We also obtained homogeneous MIP's micro-particles, which have high affinity receptor sites only using a microfluidic reactor.