Development of a microfluidic device to enrich and detect zearalenone in food using quantum dot-embedded molecularly imprinted polymers

Mycotoxins are secondary metabolites of certain moulds, prevalent in 60-80% of food crops and many processed products but challenging to eliminate. Consuming mycotoxin-contaminated food and feed can lead to various adverse effects on humans and livestock. Therefore, testing mycotoxin residue levels is critical to ensure food safety. Gold standard analytical methods rely on liquid chromatography coupled with optical detectors or mass spectrometers, which are high-cost with limited capacity. This study reported the successful development of a microfluidic "lab-on-a-chip" device to enrich and detect zearalenone in food samples based on the fluorescence quenching effect of quantum dots and selective affinity of molecularly imprinted polymers (MIPs). The dummy template and functional polymer were synthesized and characterized, and the detailed microfluidic chip design and optimization of the flow conditions in the enrichment module were discussed. The device achieved an enrichment factor of 9.6 (±0.5) in 10 min to quantify zearalenone spiked in food with high recoveries (91-105%) at 1-10 mg kg-1, covering the concerned residue levels in the regulations. Each sample-to-answer test took only 20 min, involving 3 min of manual operation and no advanced equipment. This microfluidic device was mostly reusable, with a replaceable detection module compatible with fluorescence measurement using a handheld fluorometer. To our best knowledge, the reported device was the first application of an MIP-based microfluidic sensor for detecting mycotoxin in real food samples, providing a novel, rapid, portable, and cost-effective tool for monitoring mycotoxin contamination for food safety and security.

Microfluidic synthesis of radiotracers: recent developments and commercialization prospects

Positron emission tomography (PET) is a powerful diagnostic tool that holds incredible potential for clinicians to track a wide variety of biological processes using specialized radiotracers. Currently, however, a single radiotracer accounts for over 95% of procedures, largely due to the cost of radiotracer synthesis. Microfluidic platforms provide a solution to this problem by enabling a dose-on-demand pipeline in which a single benchtop platform would synthesize a wide array of radiotracers. In this review, we will explore the field of microfluidic production of radiotracers from early research to current development. Furthermore, the benefits and drawbacks of different microfluidic reactor designs will be analyzed. Lastly, we will discuss the various engineering considerations that must be addressed to create a fully developed, commercially effective platform that can usher the field from research and development to commercialization.

Potential of CO2-laser processing of quartz for fast prototyping of microfluidic reactors and templates for 3D cell assembly over large scale

Carbon dioxide (CO2)-laser processing of glasses is a versatile maskless writing technique to engrave micro-structures with flexible control on shape and size. In this study, we present the fabrication of hundreds of microns quartz micro-channels and micro-holes by pulsed CO2-laser ablation with a focus on the great potential of the technique in microfluidics and biomedical applications. After discussing the impact of the laser processing parameters on the design process, we illustrate specific applications. First, we demonstrate the use of a serpentine microfluidic reactor prepared by combining CO2-laser ablation and post-ablation wet etching to remove surface features stemming from laser-texturing that are undesirable for channel sealing. Then, cyclic olefin copolymer micro-pillars are fabricated using laser-processed micro-holes as molds with high detail replication. The hundreds of microns conical and square pyramidal shaped pillars are used as templates to drive 3D cell assembly. Human Umbilical Vein Endothelial Cells are found to assemble in a compact and wrapping way around the micro-pillars forming a tight junction network. These applications are interesting for both Lab-on-a-Chip and Organ-on-a-Chip devices.

Continuous-Flow Production of Injectable Liposomes via a Microfluidic Approach

Injectable liposomes are characterized by a suitable size and unique lipid mixtures, which require time-consuming and nonstraightforward production processes. The complexity of the manufacturing methods may affect liposome solubility, the phase transition temperatures of the membranes, the average particle size, and the associated particle size distribution, with a possible impact on the drug encapsulation and release. By leveraging the precise steady-state control over the mixing of miscible liquids and a highly efficient heat transfer, microfluidic technology has proved to be an effective and direct methodology to produce liposomes. This approach results particularly efficient in reducing the number of the sizing steps, when compared to standard industrial methods. Here, Microfluidic Hydrodynamic Focusing chips were produced and used to form liposomes upon tuning experimental parameters such as lipids concentration and Flow-Rate-Ratios (FRRs). Although modelling evidenced the dependence of the laminar flow on the geometric constraints and the FRR conditions, for the specific formulation investigated in this study, the lipids concentration was identified as the primary factor influencing the size of the liposomes and their polydispersity index. This was attributed to a predominance of the bending elasticity modulus over the vesiculation index in the lipid mixture used. Eventually, liposomes of injectable size were produced using microfluidic one-pot synthesis in continuous flow.

Azeotropic drying free [18F]FDG synthesis and its application to a lab-on-chip platform

[¹⁸F]FDG was prepared using a cartridge-based drying technique for [¹⁸F]fluoride. The application to a lab-on-chip platform demonstrates a proof of concept towards reduced hardware complexity.

Organic synthesis: march of the machines

Organic synthesis is changing; in a world where budgets are constrained and the environmental impacts of practice are scrutinized, it is increasingly recognized that the efficient use of human resource is just as important as material use. New technologies and machines have found use as methods for transforming the way we work, addressing these issues encountered in research laboratories by enabling chemists to adopt a more holistic systems approach in their work. Modern developments in this area promote a multi-disciplinary approach and work is more efficient as a result. This Review focuses on the concepts, procedures and methods that have far-reaching implications in the chemistry world. Technologies have been grouped as topics of opportunity and their recent applications in innovative research laboratories are described.

Tribochemistry-induced direct fabrication of nondestructive nanochannels on silicon surface

A maskless, straightforward and crystal plane-independent nanofabrication approach is proposed to produce nondestructive nanochannels on monocrystalline silicon through tribochemical reaction.

A solvent resistant lab-on-chip platform for radiochemistry applications

The application of microfluidics to the synthesis of Positron Emission Tomography (PET) tracers has been explored for more than a decade. Microfluidic benefits such as superior temperature control have been successfully applied to PET tracer synthesis. However, the design of a compact microfluidic platform capable of executing a complete PET tracer synthesis workflow while maintaining prospects for commercialization remains a significant challenge. This study uses an integral system design approach to tackle commercialization challenges such as the material to process compatibility with a path towards cost effective lab-on-chip mass manufacturing from the start. It integrates all functional elements required for a simple PET tracer synthesis into one compact radiochemistry platform. For the lab-on-chip this includes the integration of on-chip valves, on-chip solid phase extraction (SPE), on-chip reactors and a reversible fluid interface while maintaining compatibility with all process chemicals, temperatures and chip mass manufacturing techniques. For the radiochemistry device it includes an automated chip-machine interface enabling one-move connection of all valve actuators and fluid connectors. A vial-based reagent supply as well as methods to transfer reagents efficiently from the vials to the chip has been integrated. After validation of all those functional elements, the microfluidic platform was exemplarily employed for the automated synthesis of a Gastrin-releasing peptide receptor (GRP-R) binding the PEGylated Bombesin BN(7-14)-derivative ([(18)F]PESIN) based PET tracer.

Microfluidics: a groundbreaking technology for PET tracer production?

Application of microfluidics to Positron Emission Tomography (PET) tracer synthesis has attracted increasing interest within the last decade. The technical advantages of microfluidics, in particular the high surface to volume ratio and resulting fast thermal heating and cooling rates of reagents can lead to reduced reaction times, increased synthesis yields and reduced by-products. In addition automated reaction optimization, reduced consumption of expensive reagents and a path towards a reduced system footprint have been successfully demonstrated. The processing of radioactivity levels required for routine production, use of microfluidic-produced PET tracer doses in preclinical and clinical imaging as well as feasibility studies on autoradiolytic decomposition have all given promising results. However, the number of microfluidic synthesizers utilized for commercial routine production of PET tracers is very limited. This study reviews the state of the art in microfluidic PET tracer synthesis, highlighting critical design aspects, strengths, weaknesses and presenting several characteristics of the diverse PET market space which are thought to have a significant impact on research, development and engineering of microfluidic devices in this field. Furthermore, the topics of batch- and single-dose production, cyclotron to quality control integration as well as centralized versus de-centralized market distribution models are addressed.

Radiochemistry on chip: towards dose-on-demand synthesis of PET radiopharmaceuticals

We have developed an integrated microfluidic platform for producing 2-[(18)F]-fluoro-2-deoxy-D-glucose ((18)F-FDG) in continuous flow from a single bolus of radioactive isotope solution, with constant product yields achieved throughout the operation that were comparable to those reported for commercially available vessel-based synthesisers (40-80%). The system would allow researchers to obtain radiopharmaceuticals in a dose-on-demand setting within a few minutes. The flexible architecture of the platform, based on a modular design, can potentially be applied to the synthesis of other radiotracers that require a two-step synthetic approach, and may be adaptable to more complex synthetic routes by implementing additional modules. It can therefore be employed for standard synthesis protocols as well as for research and development of new radiopharmaceuticals.