The fourth industrial revolution is gaining momentum in the pharmaceutical industry. However, particulate processes and suspension handling remain big challenges for automation and the implementation of real-time particle size analysis. Moreover, the development of antisolvent crystallization processes is often limited by the associated time-intensive experimental screenings.
View Article and Find Full Text PDFIn the last decade flow reactors for material synthesis were firmly established, demonstrating advantageous operating conditions, reproducible and scalable production continuous operation, as well as high-throughput screening of synthetic conditions. Reactor fouling, however, often restricts flow chemistry and the common fouling prevention segmented flow comes at the cost of inflexibility. Often, the difficulty of feeding reagents into liquid segments (droplets or slugs) constrains flow syntheses using segmented flow to simple synthetic protocols with a single reagent addition step prior or during segmentation.
View Article and Find Full Text PDFThe interaction of methylene blue and crystal violet dyes with a range of gold nanoparticles (AuNPs), gold nanoclusters and gold/silver nanoclusters is reported. It is found that 20 nm citrate-capped AuNPs have strong interactions with these two dyes that result in red-shifted absorption peaks in their electronic absorption spectra. Transmission electron microscopy and dynamic light scattering measurements show that this can be attributed to these AuNPs combining into large agglomerates.
View Article and Find Full Text PDFWe describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol.
View Article and Find Full Text PDFMagnetic nanoparticles are researched intensively not only for biomedical applications, but also for industrial applications including wastewater treatment and catalytic processes. Although these particles have been shown to have interesting surface properties in their bare form, their magnetisation remains a key feature, as it allows for magnetic separation. This makes them a promising carrier for precious materials and enables recovery via magnetic fields that can be turned on and off on demand, rather than using complex (nano)filtration strategies.
View Article and Find Full Text PDFDespite the wide usage of magnetic nanoparticles, it remains challenging to synthesise particles with properties that exploit each application's full potential. Time consuming experimental procedures and particle analysis hinder process development, which is commonly constrained to a handful of experiments without considering particle formation kinetics, reproducibility and scalability. Flow reactors are known for their potential of large-scale production and high-throughput screening of process parameters.
View Article and Find Full Text PDFMagnetically induced hyperthermia has reached a milestone in medical nanoscience and in phase III clinical trials for cancer treatment. As it relies on the heat generated by magnetic nanoparticles (NPs) when exposed to an external alternating magnetic field, the heating ability of these NPs is of paramount importance, so is their synthesis. We present a simple and fast method to produce iron oxide nanostructures with excellent heating ability that are colloidally stable in water.
View Article and Find Full Text PDFThe volumetric liquid-solid (L-S) mass transfer coefficient under gas-liquid (G-L) two-phase flow in a silicon-chip-based micropacked bed reactor (MPBR) was studied using the copper dissolution method and was related to the reactor hydrodynamic behavior. Using a high-speed camera and a robust computational image analysis method that selectively analyzed the bed voidage around the copper particles, the observed hydrodynamics were directly related to the L-S mass transfer rates in the MPBR. This hydrodynamic study revealed different pulsing structures inside the packed copper bed depending on the flow patterns established preceding the packed bed upon increasing gas velocity.
View Article and Find Full Text PDFSmall iron oxide nanoparticles (IONPs) were synthesised in water via co-precipitation by quenching particle growth after the desired magnetic iron oxide phase formed. This was achieved in a millifluidic multistage flow reactor by precisely timed addition of an acidic solution. IONPs (≤5 nm), a suitable size for positive T1 magnetic resonance imaging (MRI) contrast agents, were obtained and stabilised continuously.
View Article and Find Full Text PDFIonic gelation is commonly used to generate nanogels but often results in poor control over size and polydispersity. In this work we present a novel approach to the continuous manufacture of protein-loaded chitosan nanogels using microfluidics whereby we demonstrate high control and uniformity of the product characteristics. Specifically, a coaxial flow reactor (CFR) was employed to control the synthesis of the nanogels, comprising an inner microcapillary of internal diameter (ID) 0.
View Article and Find Full Text PDFThiolate-gold nanoclusters have various applications. However, most of the synthesis methods require prolonged synthesis times from several hours to days. In the present study, we report a rapid synthesis method for [Au(Cys)] nanoclusters and their application for photobactericidal enhancement.
View Article and Find Full Text PDFA millifluidic reactor with a 0.76 mm internal diameter was utilized for the synthesis of monodisperse, high magnetic moment, iron carbide (FeC) nanoparticles by thermal decomposition of iron pentacarbonyl (Fe(CO)) in 1-octadecene in the presence of oleylamine at 22 min nominal residence time. The effect of reaction conditions (temperature and pressure) on the size, morphology, crystal structure, and magnetic properties of the nanoparticles was investigated.
View Article and Find Full Text PDFThe emergence of antibiotic resistant bacteria is a major threat to the practice of modern medicine. Photobactericidal agents have obtained significant attention as promising candidates to kill bacteria, and they have been extensively studied. However, to obtain photobactericidal activity, an intense white light source or UV-activation is usually required.
View Article and Find Full Text PDFGas-liquid reactions are poorly explored in the context of nanomaterials synthesis, despite evidence of significant effects of dissolved gas on nanoparticle properties. This applies to the aqueous synthesis of iron oxide nanoparticles, where gaseous reactants can influence reaction rate, particle size and crystal structure. Conventional batch reactors offer poor control of gas-liquid mass transfer due to lack of control on the gas-liquid interface and are often unsafe when used at high pressure.
View Article and Find Full Text PDFCapillary microseparators have been gaining interest in downstream unit operations, especially for pharmaceutical, space, and nuclear applications, offering efficient separation of two-phase flows. In this work, a detailed analysis of the dynamics of gas?liquid separation at the single meniscus level helped to formulate a model to map the operability region of microseparation devices. A water?nitrogen segmented flow was separated in a microfabricated silicon-glass device, with a main channel (width, W = 600 ?m; height, H = 120 ?m) leading into an array of 276 capillaries (100 ?m long; width = 5 ?m facing the main channel and 25 ?m facing the liquid outlet), on both sides of the channel.
View Article and Find Full Text PDFCo-precipitation is the most ubiquitous method for forming iron oxide nanoparticles. For a typical co-precipitation synthesis, the pH of a ferrous and/or ferric ion solution is increased via the addition of a base. The latter can be added either slowly (a steady addition over either minutes or hours) or fast (a one-time addition) resulting in an abrupt increase in the pH.
View Article and Find Full Text PDFBovine serum albumin (BSA) is currently recommended as an interfering substance to emulate organic soiling, in evaluating the efficacy of disinfectants. The European Standard recommends 0.03% BSA to test clean conditions and 0.
View Article and Find Full Text PDFA multi-disciplinary cooperative for nanoparticle-enhanced radiotherapy (NERT) has been formed to review the current status of the field and identify key stages towards translation. Supported by the Colorectal Cancer Healthcare Technologies Cooperative, the cooperative comprises a diverse cohort of key contributors along the translation pathway including academics of physics, cancer and radio-biology, chemistry, nanotechnology and clinical trials, clinicians, manufacturers, industry, standards laboratories, policy makers and patients. Our aim was to leverage our combined expertise to devise solutions towards a roadmap for translation and commercialisation of NERT, in order to focus research in the direction of clinical implementation, and streamline the critical pathway from basic science to the clinic.
View Article and Find Full Text PDFIn this work we present a detailed study of flow technology approaches that could open up new possibilities for nanoparticle synthesis. The synthesis of gold and silver nanoparticles (NPs) in a flow device based on a coaxial flow reactor (CFR) was investigated. The CFR comprised of an outer glass tube of 2 mm inner diameter (I.
View Article and Find Full Text PDFA simple procedure to develop antibacterial surfaces using thiol-capped gold nanoparticles (AuNPs) is shown, which effectively kill bacteria under dark and light conditions. The effect of AuNP size and concentration on photo-activated antibacterial surfaces is reported and we show significant size effects, as well as bactericidal activity with crystal violet (CV) coated polyurethane. These materials have been proven to be powerful antibacterial surfaces against both Gram-positive and Gram-negative bacteria.
View Article and Find Full Text PDFStripping of acetone from water utilizing nitrogen as a sweeping gas in co-current flow was conducted in a microfabricated glass/silicon gas-liquid contactor. The chip consisted of a microchannel divided into a gas and a liquid chamber by 10 μm diameter micropillars located next to one of the channel walls. The channel length was 35 mm, the channel width was 220 μm and the microchannel depth 100 μm.
View Article and Find Full Text PDFA zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure.
View Article and Find Full Text PDF