Micro and Nanofabrication of Molecularly Imprinted Polymers

Nanomaterials-enriched sensors for detection of chiral pharmaceuticals

Advancements in nanoscience and nanotechnology have opened new pathways to fabricate novel nanostructures with interesting properties that would be used for different applications. In this respect, nanostructures comprising chirality are one of the most rapidly developing research fields encompassing chemistry, physics and biology. Chirality, also known as mirror asymmetry, describes the geometrical property of an object that is not superimposable on its mirror image. This characteristic plays a crucial role because these identical forms of chiral species in pharmaceuticals or food additives may exhibit different effects on living organisms. Therefore, chiral analysis is an important field of modern chemical analysis in health-related industries that are reliant on the production of enantiomeric compounds involving pharmaceuticals. This review covers the recent advances dealing with the synthesis, design and advantageous analytical performance of nanomaterials-enriched sensors used for chiral pharmaceuticals. We conclude this review with the challenges existing in this research field and our perspectives on some potential strategies with cutting-edge approaches for the rational design of sensors for chiral pharmaceuticals. We expect this comprehensive review will inspire future studies in nanomaterials-enriched chiral sensors.

Synthesis and Optimization of a Molecularly Imprinted Membrane as a Specific Absorbent to Assess the Occupational Exposure to the 5-Fluorouracil Drug

Objectives: Over the last decades, antineoplastic drugs have resulted in concerns about health care and pharmacy because of the increased incidence of neoplasm due to occupational exposure. Therefore, there is a need for accurate and valid methods to detect and evaluate the trace amount of these drugs in occupational assessment programs. In this study, for occupational exposure assessment of 5-fluorouracil (5-FU), molecularly imprinted membranes (MIMs) were synthesized and optimized as appropriate absorbents for selective determination of trace amount of this antineoplastic drug.

Methods: To synthesize MIMs as Specific adsorbent for 5-FU, First, 5-FU molecularly imprinted polymers (MIPs) were prepared by the precipitation polymerization method, and then MIPs encapsulated into PET nanofibers, as the matrix polymer, by electrospinning. Finally, MIMs were fabricated from collection nanofibers. Optimization of electrospinning parameters (e.g., MIP amount, tip needle to the collector, electrospinning voltage and flow rate) was performed by the Central Composite Design (CCD) method using the experimental design software. The diameter of the fiber was analyzed using image analysis software. The applicability of the synthesized membranes for absorbing 5-FU drug was evaluated for assessing occupational exposure to the drug of interest. Results: In this study, MIP particles were successfully encapsulated into PET nanofibers. The optimization process showed that the molecularly imprinted nanofibers diameter of 276.38[Formula: see text]nm could be obtained in 57.4%[Formula: see text]w, 13.9[Formula: see text]cm, 25[Formula: see text]KV and 0.55[Formula: see text]ml/h. The extraction efficacy of 5-FU drugs by synthesized membranes was [Formula: see text]. Conclusion: The optimized MIMs presented in this study can be used as a specific absorbent for occupational and environmental monitoring of the 5-FU drug.

Molecularly Imprinted Polymer-Based Hybrid Materials for the Development of Optical Sensors

We report on the development of new optical sensors using molecularly imprinted polymers (MIPs) combined with different materials and explore the novel strategies followed in order to overcome some of the limitations found during the last decade in terms of performance. This review pretends to offer a general overview, mainly focused on the last 3 years, on how the new fabrication procedures enable the synthesis of hybrid materials enhancing not only the recognition ability of the polymer but the optical signal. Introduction describes MIPs as biomimetic recognition elements, their properties and applications, emphasizing on each step of the fabrication/recognition procedure. The state of the art is presented and the change in the publication trend between electrochemical and optical sensor devices is thoroughly discussed according to the new fabrication and micro/nano-structuring techniques paving the way for a new generation of MIP-based optical sensors. We want to offer the reader a different perspective based on the materials science in contrast to other overviews. Different substrates for anchoring MIPs are considered and distributed in different sections according to the dimensionality and the nature of the composite, highlighting the synergetic effect obtained as a result of merging both materials to achieve the final goal.

All-organic microelectromechanical systems integrating specific molecular recognition--a new generation of chemical sensors

Cantilever-type all-organic microelectromechanical systems based on molecularly imprinted polymers for specific analyte recognition are used as chemical sensors. They are produced by a simple spray-coating-shadow-masking process. Analyte binding to the cantilever generates a measurable change in its resonance frequency. This allows label-free detection by direct mass sensing of low-molecular-weight analytes at nanomolar concentrations.

Molecularly imprinted electrochemical sensing of urinary melatonin in a microfluidic system

Melatonin levels may be related to the risks of breast cancer and prostate cancer. The measurement of urinary melatonin is also useful in monitoring serum melatonin levels following oral administration. In this work, melatonin is the target molecule, which is imprinted onto poly(ethylene-co-vinyl alcohol) by evaporation of the solvent on the working electrode of an electrochemical sensing chip. This sensing chip is used directly as a tool for optimizing the imprinting polymer composition, flow rate, and injection volume of the samples. Microfluidic sensing of the target and interference molecules revealed that the lowest detection limit is as low as ∼pM, and the electrochemical response is weak even at high interference concentrations. Poly(ethylene-co-vinyl alcohol), containing 44 mol. % ethylene, had an imprinting effectiveness of more than six-fold. In random urine analysis, the microfluidic amperometric measurements of melatonin levels with an additional and recovery of melatonin, the melatonin recovery achieved 94.78 ± 1.9% for melatonin at a concentration of 1.75-2.11 pg/mL.

Hydrogel-Based Molecularly Imprinted Polymers for Biological Detection

Molecularly imprinted polymers (MIPs) have become an important tool in the preparation of artificial and robust recognition materials that are capable of mimicking natural systems. MIPs have been regarded as 'antibody mimics' and have shown clear advantages over real antibodies for sensor technology. Currently, on-site diagnostic (OSD) and point-of-care (POC) biosensor development are heavily dominated by antibody-dependent immuno-sensors such as the lateral flow immuno-assay. Although antibodies exhibit a high degree of selectivity, any biological recognition element is inherently unstable with limited shelf-life, even when stored under optimum conditions. OSD and POC tests are essential for disease screening and treatment monitoring as part of emergency management. Introduced or naturally occurring pathogens can cause significant disruptions, raise panic in the population, and result in significant economic losses. Cheaper, smaller, and smarter devices for early detection of disease or environmental hazards ultimately lead to rapid containment and corrective action. To this end, there has been extensive research on detection platforms based on genetic or immune techniques. MIPs have proven to produce selective biological extractions that rival immunoaffinity-based separations, but without the tediously lengthy time-consuming process. MIPs could provide an alternative to antibodies, and ultimately lead to cheaper, smaller, and smarter biosensors.

Hot Spot-Localized Artificial Antibodies for Label-Free Plasmonic Biosensing

The development of biomolecular imprinting over the last decade has raised promising perspectives in replacing natural antibodies with artificial antibodies. A significant number of reports have been dedicated to imprinting of organic and inorganic nanostructures, but very few were performed on nanomaterials with a transduction function. Herein we describe a relatively fast and efficient plasmonic hot spot-localized surface imprinting of gold nanorods using reversible template immobilization and siloxane co-polymerization. The technique enables a fine control of the imprinting process at the nanometer scale and provides a nanobiosensor with high selectivity and reusability. Proof of concept is established by the detection of neutrophil gelatinase-associated lipocalin (NGAL), a biomarker for acute kidney injury, using localized surface plasmon resonance spectroscopy. The work represents a valuable step towards plasmonic nanobiosensors with synthetic antibodies for label-free and cost-efficient diagnostic assays. We expect that this novel class of surface imprinted plasmonic nanomaterials will open up new possibilities in advancing biomedical applications of plasmonic nanostructures.