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To overcome the technical limitations of current batch reactors for synthesizing N-2-HACC/CMCS NPs, an ultrasonic microreactor was designed and fabricated to continuously prepare N-2-HACC/CMCS NPs, which were characterized by SEM, laser particle sizing instrument, and FTIR. The findings indicate that the granular size of the NPs can be precisely regulated by changing the conditions of reaction temperature, ultrasonic power, reactant flux ratio, and reactant concentration. Compared with the batch reactor, ultrasonic microreactors can continuously prepare NPs with smaller and more uniform particle sizes.

Photochemical activation routes are gaining the attention of the scientific community since they can offer an alternative to the traditional chemical industry that mainly utilizes thermochemical activation of molecules. Photoreactions are fast and selective, which would potentially reduce the downstream costs significantly if the process is optimized properly. With the transition towards green chemistry, the traditional batch photoreactor operation is becoming abundant in this field. Process intensification efforts led to micro- and mesostructured flow photoreactors. In this work, we are reviewing structured photoreactors by elaborating on the bottleneck of this field: the development of an efficient scale-up strategy. In line with this, micro- and mesostructured bench-scale photoreactors were evaluated based on a new benchmark called photochemical space time yield (mol·day −1 ·kW −1 ), which takes into account the energy efficiency of the photoreactors. It was manifested that along with the selection of the photoreactor dimensions and an appropriate light source, optimization of the process conditions, such as the residence time and the concentration of the photoactive molecule is also crucial for an efficient photoreactor operation. In this paper, we are aiming to give a comprehensive understanding for scale-up strategies by benchmarking selected photoreactors and by discussing transport phenomena in several other photoreactors.

Liquid–liquid phase separation of disordered proteins has emerged as a ubiquitous route to membraneless compartments in living cells, and similar coacervates may have played a role when the first cells formed. However, existing coacervates are typically made of multiple macromolecular components, and designing short peptide analogues capable of self-coacervation has proven difficult. Here we present a short peptide synthon for phase separation, made of only two dipeptide stickers linked via a flexible, hydrophilic spacer. These small-molecule compounds self-coacervate into micrometre-sized liquid droplets at sub-millimolar concentrations, which retain up to 75 wt% water. The design is general and we derive guidelines for the required sticker hydrophobicity and spacer polarity. To illustrate their potential as protocells, we create a disulfide-linked derivative that undergoes reversible compartmentalization controlled by redox chemistry. The resulting coacervates sequester and melt nucleic acids, and act as microreactors that catalyse two different anabolic reactions yielding molecules of increasing complexity. This provides a stepping stone for new coacervate-based protocells made of single peptide species.Liquid–liquid phase separation plays an important role in creating cellular compartments and protocells, but designing small-molecule models remains difficult. A peptide-based synthon for liquid–liquid phase separation consisting of two stickers and a flexible, polar spacer has now been presented. Condensates formed by these synthons can concentrate biomolecules and catalyse anabolic reactions.

Microfluidic technology is highly effective in enhancing the chemical reactions’ kinetics. Microreactors take advantage of the microflow phenomenon. Obstacle-based microreactors have proved their effectiveness in enhancing the rates of mass transfer, therefore, they hold reactions with limited mass transfer rate for improving yield, and selectivity. In this work, the semi-circular obstacles are investigated for their effect on mixing enhancement rather than the circular obstacles. Herein, circular obstacles are split into two semi-circular obstacles to study the effect of increasing the sub-streams to three instead of two only. Splitting the circular obstacles into two semi-circles demonstrated significant improvement regarding the mixing quality. Semi-circular obtsacles improves the mixing index, espcially at higher Reynolds number. At Re =100 the mixing index increased from 56.94% with one circular obstacle to 94.07% with two semi-circular obstacles, that means mixing efficiency is enhanced by 65%.

A continuous flow cascade of multi-step catalytic reactions is a cutting-edge concept to revolutionize stepwise catalytic synthesis yet is still challenging in practical applications. Herein, a method for practical one-pot cascade catalysis is developed by combining Pickering emulsions with continuous flow. Our method involves co-localization of different catalytically active sub-compartments within droplets of a Pickering emulsion yielding cell-like microreactors, which can be packed in a column reactor for continuous flow cascade catalysis. As exemplified by two chemo-enzymatic cascade reactions for the synthesis of chiral cyanohydrins and chiral ester, 5 − 420 fold enhancement in the catalysis efficiency and as high as 99% enantioselectivity were obtained even over a period of 80 − 240 h. The compartmentalization effect and enriching-reactant properties arising from the biomimetic microreactor are theoretically and experimentally identified as the key factors for boosting the catalysis efficiency and for regulating the kinetics of cascade catalysis. A continuous flow cascade of multi-step catalytic reactions would provide significant advantages in faster reaction times, waste reduction, and lowered step-count of syntheses, yet this ideal remains challenging in practical applications. Here the authors describe continuous flow cascade catalysis through co-localization of two catalytically active subcompartments within Pickering emulsion droplets.

In this paper, we report on a digital PCR chip integrated with microchannel plate (MCP) for the quantification of DNA molecules. MCP, a highly porous glass membrane, is employed here as microreactors. The density of the microreactors reaches up to 1600 mm −2 with a total number of 40,000 chambers each in 100 pL volumes embedded in a 5 × 5 mm 2 MCP, which is 100 times larger than that of the conventional microfabricated chips. In addition, the MCP is functionalized with ZnO nanorods to enhance the fluorescence signal. The dynamic range is noted as 10 5 and the detection limit of λDNA is determined to be 1.4 copies/μL.

Suspended aqueous aerosol droplets (<50 μm) are microreactors for many important atmospheric reactions. In droplets and other aquatic environments, pH is arguably the key parameter dictating chemical and biological processes. The nature of the droplet air/water interface has the potential to significantly alter droplet pH relative to bulk water. Historically, it has been challenging to measure the pH of individual droplets because of their inaccessibility to conventional pH probes. In this study, we scanned droplets containing 4-mercaptobenzoic acid–functionalized gold nanoparticle pH nanoprobes by 2D and 3D laser confocal Raman microscopy. Using surface-enhanced Raman scattering, we acquired the pH distribution inside approximately 20-μm-diameter phosphate-buffered aerosol droplets and found that the pH in the core of a droplet is higher than that of bulk solution by up to 3.6 pH units. This finding suggests the accumulation of protons at the air/water interface and is consistent with recent thermodynamic model results. The existence of this pH shift was corroborated by the observation that a catalytic reaction that occurs only under basic conditions (i.e., dimerization of 4-aminothiophenol to produce dimercaptoazobenzene) occurs within the high pH core of a droplet, but not in bulk solution. Our nanoparticle probe enables pH quantification through the cross-section of an aerosol droplet, revealing a spatial gradient that has implications for acid-base–catalyzed atmospheric chemistry.

For the next-generation high temperature microreactors, yttrium dihydride (YH2) is an attractive solid state neutron moderator. Despite a number of recent investigations, the mechanism of hydrogen transport remains poorly understood. Experimental evaluations of diffusivity are inconclusive with large variations in diffusivities and activation energies. In this work, we perform ab initio molecular dynamics (AIMD) simulations on YH2 for temperatures spanning 300 K to 1200 K. Our main finding is that YH2 shows a superionic-like behavior with hydrogen atoms hopping from one native site to another above a characteristic temperature of 800 K. This correlated motion results in quasi-one-dimensional string-like displacements that enable the hydrogen atoms to diffuse rapidly. We confirm that the octahedral sites are mostly unoccupied, although channeling through them is the most favored pathway between lattice hops above 800 K. At the highest temperature of 1200 K, the string relaxation time is merely of the order of a few picoseconds, which indicates a liquid-like diffusive behavior. Based on the formation of spontaneous thermal vacancies, an order-disorder crossover temperature Tα 800 K is established for YH2 with an activation energy of 0.83 eV for hydrogen diffusion in the superionic-like state.

Bioinspired multi-compartment architectures are desired in synthetic biology and metabolic engineering, as credited by their cell-like structures and intrinsic ability of assembling catalytic species for spatiotemporal control over cascade reactions like in living systems. Herein, we describe a general Pickering double emulsion-directed interfacial synthesis method for the fabrication of multicompartmental MOF microreactors. This approach employs multiple liquid–liquid interfaces as a controllable platform for the self-completing growth of dense MOF layers, enabling the microreactor with tailor-made inner architectures and selective permeability. Importantly, simultaneous encapsulation of incompatible functionalities, including hydrophilic enzyme and hydrophobic molecular catalyst, can be realized in a single MOF microreactor for operating chemo-enzymatic cascade reactions. As exemplified by the Grubb’ catalyst/CALB lipase driven olefin metathesis/ transesterification cascade reaction and glucose oxidase (GOx)/Fe-porphyrin catalyzed oxidation reaction, the multicompartmental microreactor exhibits 2.24–5.81 folds enhancement in cascade reaction efficiency in comparison to the homogeneous counterparts or physical mixture of individual analogues, due to the restrained mutual inactivation and substrate channelling effects. Our study prompts further design of multicompartment systems and the development of artificial cells capable of complex cellular transformations. The cell-like structures and the ability of assembling catalytic species are interesting features of bioinspired multicompartment architectures but it remains a challenge to build them. Here, the authors describe a Pickering double emulsion-directed interfacial synthesis to fabricate multi-compartmented metal-organic framework microreactors. The cell-like structures and the ability of assembling catalytic species are interesting features of bioinspired multicompartment architectures but it remains a challenge to build them. Here, the authors describe a Pickering double emulsion-directed interfacial synthesis to fabricate multi-compartmented metal-organic framework microreactors.

Living cells harvest energy from their environments to drive the chemical processes that enable life. We introduce a minimal system that operates at similar protein concentrations, metabolic densities, and length scales as living cells. This approach takes advantage of the tendency of phase-separated protein droplets to strongly partition enzymes, while presenting minimal barriers to transport of small molecules across their interface. By dispersing these microreactors in a reservoir of substrate-loaded buffer, we achieve steady states at metabolic densities that match those of the hungriest microorganisms. We further demonstrate the formation of steady pH gradients, capable of driving microscopic flows. Our approach enables the investigation of the function of diverse enzymes in environments that mimic cytoplasm, and provides a flexible platform for studying the collective behavior of matter driven far from equilibrium. Living cells can harvest environmental energy to drive chemical processes. Here the authors design a minimal artificial system that achieves steady states at similar metabolic densities to microorganisms.