Fluorescent Molecularly Imprinted Polymer Research Articles

Efficient synthesis of the undiluted vegetable juice-compatible hydrophilic quantum dot-labeled fluorescent molecularly imprinted polymer microspheres via facile one-pot surface-initiated ARGET ATRP

The development of fluorescent molecularly imprinted polymers (MIPs) applicable for herbicide optosensing in the undiluted vegetable juices is highly important for food safety control, but still remains a challenging task. Herein, we report on a facile and efficient new strategy for the synthesis of hydrophilic quantum dot (QD)-labeled fluorescent MIP microspheres capable of directly and selectively optosensing a widely used herbicide (i.e., 2,4-dichlorophenoxyacetic acid, 2,4-D) in the undiluted vegetable juices. Such fluorescent MIP particles were readily prepared through one-step grafting of a red CdTe QD-labeled 2,4-D-MIP layer with hydrophilic polyethylene glycol brushes onto the preformed uniform “living” polymer microspheres (with surface-bound alkyl halide groups) via one-pot surface-initiated activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) (SI-ARGET ATRP). They proved to be a highly useful optosensor with high 2,4-D selectivity and sensitivity (the limit of detection ≤ 0.14 μM) in the undiluted Chinese cabbage and cucumber juices. They also showed excellent photostability and reusability and could be directly utilized for 2,4-D detection with high recoveries (98.2 %-102.4 %) and accuracy (RSD≤3.8 %) in the undiluted Chinese cabbage and cucumber juices at three spiking levels of both 2,4-D and its mixtures with several analogues. The use of SI-ARGET ATRP significantly reduced the applied copper catalyst concentration (about 5 μM), which greatly alleviated the quenching effect of the copper catalyst on the fluorescence of the QD-labeled MIP (usually observed for those prepared via normal ATRPs that typically use several hundreds of μM of copper catalysts), thus making this facile new strategy highly efficient for developing advanced fluorescent MIPs that hold much promise in various bioanalytical and diagnostic applications.

One-Pot Preparation of Ratiometric Fluorescent Molecularly Imprinted Polymer Nanosensor for Sensitive and Selective Detection of 2,4-Dichlorophenoxyacetic Acid.

The development of fluorescent molecular imprinting sensors for direct, rapid, and sensitive detection of small organic molecules in aqueous systems has always presented a significant challenge in the field of detection. In this study, we successfully prepared a hydrophilic colloidal molecular imprinted polymer (MIP) with 2,4-dichlorophenoxyacetic acid (2,4-D) using a one-pot approach that incorporated polyglycerol methacrylate (PGMMA-TTC), a hydrophilic macromolecular chain transfer agent, to mediate reversible addition-fragmentation chain transfer precipitation polymerization (RAFTPP). To simplify the polymerization process while achieving ratiometric fluorescence detection, red fluorescent CdTe quantum dots (QDs) and green fluorescent nitrobenzodiazole (NBD) were introduced as fluorophores (with NBD serving as an enhancer to the template and QDs being inert). This strategy effectively eliminated background noise and significantly improved detection accuracy. Uniform-sized MIP microspheres with high surface hydrophilicity and incorporated ratiometric fluorescent labels were successfully synthesized. In aqueous systems, the hydrophilic ratio fluorescent MIP exhibited a linear response range from 0 to 25 μM for the template molecule 2,4-D with a detection limit of 0.13 μM. These results demonstrate that the ratiometric fluorescent MIP possesses excellent recognition characteristics and selectivity towards 2,4-D, thus, making it suitable for selective detection of trace amounts of pesticide 2,4-D in aqueous systems.

Fluorescent molecularly imprinted polymer nanocomposite for solid-phase extraction and fluorimetric determination of hydrochlorothiazide.

We report herein a fluorescent molecularly imprinted polymer (FMIP) for the solid-phase extraction (SPE) and fluorimetric determination of hydrochlorothiazide (HCTZ) in water. The FMIP is based on fluorescent polystyrene nanoparticles embedded within a molecularly imprinted polyaniline (PANI) matrix. The operational adsorption parameters such as the initial HCTZ concentration, incubation time and the solution pH were found to influence the removal efficiency. At optimum conditions, a high adsorption capacity of the FMIP was found (2.08 mg g-1). Evidence of the adsorption process was confirmed by the change in the FMIP physicochemical properties measured by FTIR absorption spectroscopy and electron microscopy. Based on the regression R2 values and the consistently low values of the adsorption statistical error functions, equilibrium data were best fitted to both Freundlich and Temkin isotherms. Moreover, the pseudo-second-order kinetic model described the adsorption kinetics, and the mechanism of the adsorption process was explained by the intraparticle diffusion model. Upon studying adsorption thermodynamics, negative ΔG values (-26.18 kJ mol-1 at room temperature) were obtained revealing that the adsorption process is spontaneous. Interestingly, the maximum adsorption capacity was obtained at 298 K, pH 7.0, and using a high HCTZ concentration, thus revealing the suitability of the proposed FMIP for easy and fast SPE of HCTZ. The FMIP showed an imprinting factor of 1.19 implying the selectivity over the corresponding FNIP. Eventually, the proposed FMIP was successfully applied to the spectrofluorimetric determination of HCTZ in aqueous samples with %recovery values close to 100%.

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.

A soluble-fluorescent surface molecularly imprinted polymer sensor based on combined soluble solid phase-and liquid–liquid-microextraction

The rigid and highly cross-linked nature of fluorescent molecularly imprinted polymer (FMIP) make it dispersive in solution and cause scattering of source light which limits the application of FMIP in photoluminescence sensors. In addition, the distribution of FMIPs in the solution is unstable and in some cases their rapid settlement deviate the accuracy and precision of measurement. In this work, a miniaturized probe based on the soluble-fluorescent surface molecularly imprinted polymer (S-FSMIP) was developed and conveniently implemented to detect sertraline (SER), as a model target, in human urine. The developed probe synthesis was conducted in two main steps: i) design of FSMIP with hydrophobic core and hydrophilic surface, ii) swelling process of FSMIP at a high temperature in the presence of a high boiling hydrophobic deep eutectic solvent (HDES). Employment of HDES as a green solvent for solvation of FSMIP minimizes the consumption of hazardous chemicals and also improves analyte transfer to surface of FMIP. The adsorption isotherm and adsorption kinetic of the S-FSMIP were also studied and compared with FSMIP. Accordingly, the analytical parameters such as linearity, limits of detection, limits of quantification, relative standard deviations and the absolute recovery values were provided for this rapid and green-oriented method.

Determination of total cathinones with a single molecularly imprinted fluorescent sensor assisted by electromembrane microextraction.

Anelectromembrane microextraction (EME)-assisted fluorescent molecularly imprinted polymer (MIP) sensing method is presentedfor detecting the total cathinone drugs in urine samples. In this detection system, the clean-up ability of EME eliminated the matrix effects on both target binding with MIPs and the luminescence of the fluorophore in the sensor. Moreover, by optimizing the extraction conditions of EME, different cathinone drugs with a same concentration show a same response on the single aggregation induced emission (AIE) based MIP (AIE-MIP) sensor (λex = 360nm, λem = 467nm). The recoveries were 57.9% for cathinone (CAT) and 78.2% for methcathinone (MCAT). The EME-assisted "light-up" AIE-MIP sensing method displayed excellent performance with a linear range of 2.0-12.0μmol L-1 and a linear determination coefficient (R2) of 0.99. The limit of detection (LOD) value for EME-assisted "light-up" AIE-MIP sensing method was 0.3μmol L-1. The relative standard deviation (RSD) values for the detection were found to be within the range 2.0-12.0%. To the best of our knowledge, this is the first time that determination of total illicit drugs with a single fluorescent MIP sensor was achieved and also the first utilization of sample preparation to tune the sensing signal of the sensor to be reported. We believe that this versatile combination of fluorescent MIP sensor and sample preparation can be used as a common protocol for sensing the total amount of a group of analytes in various fields.

A simple approach to prepare fluorescent molecularly imprinted nanoparticles.

Fluorescent molecularly imprinted polymers (FMIPs) are gaining increasing attention in analytical and medical sciences, particularly silica-based FMIPs due to their low cost, environmentally friendly nature and good biocompatibility. However, at present, silica-based FMIPs are usually prepared through several steps and displayed low selectivity. Here, a simple approach was utilized for preparing silica-based FMIP nanoparticles. The polymerization was initiated by 3-aminopropyltriethoxysilane (APTES), which also acted as the functional monomer in the imprinting system; in addition, to achieve one-pot synthesis, a fluorescent monomer was prepared by a simple reaction between fluorescein isothiocyanate (FITC) and APTES. The as-synthesized FMIP nanoparticles displayed high specificity and fast response time (<1 min) towards the target molecule. Environmental pH and buffer salt could affect the specific recognition behaviors of the FMIP nanoparticles. Such a simple catalyst-free synthetic technique could also be employed for the preparation of FMIP nanoparticles targeting other acidic molecules.

Biological Sample-Compatible Ratiometric Fluorescent Molecularly Imprinted Polymer Microspheres by RAFT Coupling Chemistry.

Ratiometric fluorescent molecularly imprinted polymer (MIP) sensors hold great promise in many bioanalytical areas because of their high sensitivity and selectivity as well as excellent self-referencing and visual detection capability. However, their synthetic strategies are rather limited and the development of such optosensing MIPs that can directly and selectively quantify small organic analytes in complex biological samples remains a formidable challenge owing to the complexity of sample matrices. Herein, a versatile and modular strategy to obtaining well-defined ratiometric fluorescent MIP microspheres capable of directly and selectively detecting an organic herbicide [2,4-dichlorophenoxyacetic acid (2,4-D)] in undiluted pure milks is described. First, it involves the synthesis of uniform "living" polymer particles via RAFT precipitation polymerization, their successive well-controlled grafting of a polymer shell labeled with red CdTe QDs (being inert to 2,4-D) and an MIP shell labeled with green 4-nitrobenzo[c][1,2,5]oxadiazole (NBD) units (showing fluorescence "light-up" upon binding 2,4-D) via surface-initiated RAFT polymerization, and final grafting of hydrophilic poly(N-isopropylacrylamide) brushes via an efficient coupling reaction (i.e., RAFT coupling chemistry). The resulting hydrophilic dual fluorescent MIP particles showed excellent photostability and reusability. They exhibited obvious analyte binding-induced "turn-on"-type ratiometric fluorescence (and color) change and high 2,4-D optosensing selectivity and sensitivity in pure bovine milk (with a detection limit of 0.13 μM). Moreover, they were directly applied to 2,4-D determination in undiluted pure goat milk with good recoveries (96.0-103.2%) and high accuracy (RSD = 1.5-5.5%), even in the presence of several analogues of 2,4-D. The general applicability of our strategy was also demonstrated. This study paves the way for efficiently developing various advanced MIP optosensors (of easily tunable structures and desired properties) highly promising in many bioanalytical applications.

Fluorometric determination of acetamiprid using molecularly imprinted upconversion nanoparticles

This paper describes the fabrication ofan imprinted fluorescent nanoprobe based on SiO2-coated NaYF4: Yb, Er upconversion nanoparticles (UCNP) encapsulated with a molecularly imprinted polymer (MIP) for determination of acetamiprid. The fluorescent MIP nanoprobe was prepared using UCNP as the material forfluorescence signal readout, acetamiprid as template molecule, methylacrylic acid (MAA) as functional monomer, and ethyleneglycol dimethacrylate (EGDMA) as cross-linking agent. The molecular imprinting layers were immobilized on the surface of the UCNP@SiO2 by polymerization which occurred between the double bonds. UCNP@MIP shows a high selectivity towards acetamiprid with an imprinting factor (IF) of 7.84. When UCNP@MIP combines with acetamiprid, the fluorescence of the UCNP@MIP can be quenched due to the photo-induced electron transfer. Under optimum conditions, the fluorescence method shows a good linear relationship between the decreased fluorescence intensity (with excitation/emission peaks at 980/542nm) and the variation of acetamiprid in the concentration range 20 to 800ngmL-1. The limit of detection (LOD) is 8.3ngmL-1. This fluorescence method was also successfully applied to detect acetamiprid in apple and strawberry samples. The recoveries range from 89.6 to 97.9%, with relative standard deviations between 1.6 and 2.9% (n = 5). Graphical abstractA simple fluorescence nanoprobe which integrates upconversion nanoparticles (UCNPs) and molecular imprinting polymer (MIP) was developed for the determination of acetamiprid. The limit of the detection was determined as 8.3ngmL-1. The selectivity was enhanced by molecular imprinting, and the sensitivity was improved by the high sensitivity of the fluorescence emitted from the UCNPs.

Selective Recognition of Herbicides in Water Using a Fluorescent Molecularly Imprinted Polymer Sensor.

Fluorescent molecularly imprinted polymer (FMIP) optosensor was utilized for the selective identification of 2,4-dichlorophenoxacetic acid (2,4-D) due to worldwide pollution caused by using herbicides in agricultural industry. In this regards, two derivatives of polymerizable 1,8-naphthalimide namely, 1,8-naphthalimide containing thiourea (NI) and diethyl amine tagged 1,8-naphthalimide (NII) were used as the receptors and 2,4-D was applied as a template. Also, precipitation polymerization was applied to prepare the fluorescent molecularly imprinted polymer (FMIP). The morphological, structural and thermal analysis was carried out using SEM, TEM, EDS, BET, FTIR, DSC and TGA for characterizing the fluorescent optosensor. The adsorption efficiency of FMIP and FNIP was studied using Langmuir, Freundlich, BET and Redlich Peterson isotherms. The results represented that the adsorption of 2,4-D on FMIP and FNIP agreed the Freundlich adsorption isotherm with correlation coefficient of 0.9935 and 0.9801, respectively. The prepared sensor was able for the selective determination of 2,4-D salt in the linear range of 5 × 10-7-1 × 10-3M with a limit of detection of 16.8nM. The present study revealed that the FMIP prepared by 1,8-naphthalimide derivative (NI) could potentially recognize the trace concentration of 2,4-D. Graphical Abstract Graphical abstract of flourescene switching mechanism in a fluorescent molecularly imprinted polymer sensor.

Well-defined hydrophilic “turn-on”-type ratiometric fluorescent molecularly imprinted polymer microspheres for direct and highly selective herbicide optosensing in the undiluted pure milks

Molecularly imprinted polymer (MIP)-based optosensing materials capable of direct, reliable, and highly selective detection of small organic analytes in complex aqueous samples hold great promise in many bioanalytical applications, but their development remains a challenging task. Addressing this issue, well-defined hydrophilic “turn-on”-type ratiometric fluorescent MIP microspheres are developed via a versatile and modular strategy based on the controlled/“living” radical polymerization method. Its general principle was demonstrated by the synthesis of red CdTe quantum dot (QD)-labeled silica particles with surface-bound atom transfer radical polymerization (ATRP)-initiating groups via the one-pot sol-gel reaction and their successive grafting of a thin fluorescent 2,4-D (an organic herbicide)-MIP layer (labeled with green organic fluorophores bearing both nitrobenzoxadiazole (NBD) and urea interacting groups) and hydrophilic poly(glyceryl monomethacrylate) (PGMMA) brushes via surface-initiated ATRP. The introduction of PGMMA brushes and rationally selected dual fluorescence labeling (i.e., red CdTe QDs being inert to 2,4-D and green NBD showing fluorescence “light-up” upon binding 2,4-D) onto MIP particles afforded them excellent complex aqueous sample-compatibility (due to their largely enhanced hydrophilicity) and analyte binding-induced “turn-on”-type ratiometric fluorescence changes, respectively. Such advanced MIP particles proved to be promising optosensing materials, which had a detection limit of 0.13 μM and showed obvious fluorescent color change upon binding different concentrations of 2,4-D in the undiluted pure milk. Moreover, they were successfully applied for direct and highly selective quantification of 2,4-D in the undiluted pure goat and bovine milks with good recoveries (97.9%–104.5%), even in the presence of several analogues of 2,4-D.

A facile, green synthesis of biomass carbon dots coupled with molecularly imprinted polymers for highly selective detection of oxytetracycline

Biomass carbon dots (CDs) prepared by sweet potato peels were superior fluorophores with low toxicity and excellent photostability. A novel designed fluorescence probe for specific recognition and sensitive detection of oxytetracycline (OTC) was fabricated with CDs and molecularly imprinted polymer (MIP). The quenching of CDs happened when rebinding with OTC due to electron-transfer-induced fluorescence quenching mechanism. The fluorescence probe was successfully applied in honey with the recoveries ranging from 90.2% to 97.3%. The detection limit of OTC was 15.3ngmL−1. This work provides promising perspectives that the development of fluorescent MIP will be valuable for rapid analysis in complex samples.

A fluorescent molecularly imprinted polymer using aptamer as a functional monomer for sensing of kanamycin

This paper describes an alternative strategy for fabricating a fluorescent aptamer functionalized molecularly imprinted polymer (MIP) for highly specific sensing of kanamycin. The technique provides surface imprinting in aqueous solutions using CdSe quantum dots as supports, thiols modified aptamer and methacrylic acid as functional monomers, and kanamycin as a template. The MIP would function utilizing double recognition of the aptamer and imprinted cavities for fluorescent sensing of kanamycin. The “thiol-ene” click reaction was utilized to fix the aptamer into polymer matrix, and the click chemistry used was highly efficient under mild condition and environmentally friendly. Experimental results indicated that there was a synergistic interaction between the aptamer and MAA, which improved the recognition ability of MIP toward kanamycin. The MIP showed an imprinting factor of 3.51 for kanamycin, excellent analog selectivity, and strong resistance toward ions interference. The fluorescence intensity of the MIP enhanced gradually with increase in the concentration of kanamycin, and exhibited good linear correlation within the concentration of 0.05–10.0 μg/mL with a detection limit of 0.013 μg/mL. This fluorescent MIP was further applied to quickly, sensitively and simply sensing of kanamycin in food, water and biological samples which yielded satisfied results.

Integrating fluorescent molecularly imprinted polymer (MIP) sensor particles with a modular microfluidic platform for nanomolar small-molecule detection directly in aqueous samples

Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the selective determination of a prototype small-molecule analyte of environmental concern, 2,4-dichlorophenoxyacetic acid or 2,4-D, at nanomolar concentration directly in water samples. A tailor-made fluorescent indicator cross-linker was thus designed that translates the binding event directly into an enhanced fluorescence signal. The phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles following a RAFT (reversible addition-fragmentation chain transfer) polymerization protocol. While the indicator cross-linker outperformed its corresponding monomer twin, establishment of a phase-transfer protocol was essential to guarantee that the hydrogen bond-mediated signalling mechanism between the urea binding site on the indicator cross-linker and the carboxylate group of the analyte was still operative upon real sample analysis. The latter was achieved by integration of the fluorescent core-shell MIP sensor particles into a modular microfluidic platform that allows for an in-line phase-transfer assay, extracting the analyte from aqueous sample droplets into the organic phase that contains the sensor particles. Real-time fluorescence determination of 2,4-D down to 20nM was realized with the system and applied for the analysis of various surface water samples collected from different parts of the world.

Core-Shell Molecularly Imprinted Polymer Nanoparticles as Synthetic Antibodies in a Sandwich Fluoroimmunoassay for Trypsin Determination in Human Serum.

We describe the application of a fluorescently labeled water-soluble core-shell molecularly imprinted polymer (MIP) for fluorescence immunoassay (FIA) to detect trypsin. p-Aminobenzamidine (PAB), a competitive inhibitor of trypsin, was immobilized in the wells of a microtiter plate enabling the capture of trypsin in an oriented position, thus maintaining its native conformation. Fluorescent MIP nanoparticles, which bound selectively to trypsin, were used for quantification. The MIP was prepared by a multistep solid-phase synthesis approach on glass beads functionalized with PAB, orientating all trypsin molecules in the same way. The core-MIP was first synthesized, using a thermoresponsive polymer based on N-isopropylacrylamide, so as to enable its facile liberation from the immobilized template by a simple temperature change. The shell, mainly composed of allylamine to introduce primary amino groups for postconjugation of fluorescein isothiocyanate (FITC), was grafted in situ on the core-MIP, whose binding cavities were still bound and protected by the immobilized trypsin. The resulting core-shell MIP was endowed with a homogeneous population of high-affinity binding sites, all having the same orientation. The MIP has no or little cross-reactivity with other serine proteases and unrelated proteins. Our MIP-based FIA system was successfully applied to detect low trypsin concentrations spiked into nondiluted human serum with a low limit of quantification of 50 pM, which indicates the significant potential of this assay for analytical and biomedical diagnosis applications.

A fluorescent glycosyl-imprinted polymer for pH and temperature regulated sensing of target glycopeptide antibiotic

This paper demonstrates a new strategy for developing a fluorescent glycosyl-imprinted polymer for pH and temperature regulated sensing of target glycopeptide antibiotic. The technique provides amino modified Mn-doped ZnS QDs as fluorescent supports, 4-vinylphenylbronic acid as a covalent monomer, N-isopropyl acrylamide as a thermo-responsive monomer in combination with acrylamide as a non-covalent monomer, and glycosyl moiety of a glycopeptide antibiotic as a template to produce fluorescent molecularly imprinted polymer (FMIP) in aqueous solution. The FMIP can alter its functional moieties and structure with pH and temperature stimulation. This allows recognition of target molecules through control of pH and temperature. The fluorescence intensity of the FMIP was enhanced gradually as the concentration of telavancin increased, and showed selective recognition toward the target glycopeptide antibiotic preferentially among other antibiotics. Using the FMIP as a sensing material, good linear correlations were obtained over the concentration range of 3.0–300.0μg/L and with a low limit of detection of 1.0μg/L. The analysis results of telavancin in real samples were consistent with that obtained by liquid chromatography tandem mass spectrometry.

One-pot synthesis of quantum dot-labeled hydrophilic molecularly imprinted polymer nanoparticles for direct optosensing of folic acid in real, undiluted biological samples

A facile and efficient one-pot approach for the synthesis of quantum dot (QD)-labeled hydrophilic molecularly imprinted polymer (MIP) nanoparticles for direct optosensing of folic acid (FA) in the undiluted bovine and porcine serums is described. Hydrophilic macromolecular chain transfer agent-mediated reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization was used to implement the molecular imprinting of FA in the presence of CdTe quantum dots (QDs). The resulting FA-imprinted polymer nanoparticles with surface-grafted hydrophilic poly(glyceryl monomethacrylate) brushes and QDs labeling not only showed outstanding specific molecular recognition toward FA in biological samples, but also exhibited good photostability, rapid binding kinetics, and obvious template binding-induced fluorescence quenching. These characteristics make them a useful fluorescent chemosensor for directly and selectively optosensing FA in the undiluted bovine and porcine serums, with its limit of detection being 0.025μM and average recoveries ranging from 98% to 102%, even in the presence of several interfering compounds. This advanced fluorescent MIP chemosensor is highly promising for rapid quantification of FA in such applications as clinical diagnostics and food analysis.

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.

Synthesis, characterization and in vivo drug delivery study of a biodegradable nano-structured molecularly imprinted polymer based on cross-linker of fructose

In this study, a new biodegradable cross-linker agent based on fructose was reported for fabrication of brain targeted molecularly imprinted polymer (MIP). The applied strategy for targeting drug delivery was based on two mechanisms. Firstly, the magnetic structure of prepared MIP which facilitates the aggregation of carrier near target tissue under magnetic field. Second, the tendency of brain cell to use the produced fructose during degradation of MIP as fuel. In synthesis procedure magnetic fluorescent multi core shell structure MIP was prepared via co-precipitation polymerization in the presence of olanzapine as template and fructose with double acts, as monomer and cross-linker. Various kinds of in vitro and in vivo experiments were carried out to indicate the considered properties of carrier. The obtained data confirmed the designed carrier olanzapine satisfactorily meet the requirement in brain drug delivery application.

A fluorescent molecularly imprinted polymer sensor synthesized by atom transfer radical precipitation polymerization for determination of ultra trace fenvalerate in the environment

In this study, novel fluorescence molecularly imprinted polymers (FMIPs) were prepared via atom transfer radical precipitation polymerization (ATRPP) for the optical detection of trace fenvalerate (FE).