A novel microfluidic approach for extremely fast and efficient photochemical transformations in fluoropolymer microcapillary films

The unique optical properties of the fluoropolymer microcapillary film (MCF) material combined with the extremely fast photoinactivation of Herpes HSV-1 virus, and photodegradation of indigo carmine, diclofenac and benzoylecgonine in the MCF array photoreactor, demonstrate a new, flexible and inexpensive platform for rapid photochemical transformations, high-throughput process analytics and photochemical synthesis

Intensification of ozonation processes in a novel, compact, multi-orifice oscillatory baffled column

A novel approach for the intensification of ozonation of water and wastewater is presented using a highly efficient and compact Multi-Orifice Oscillatory Baffled Column (MOBC) ozonation contactor. The MOBC uniquely yielded full (i.e. 100%) use of the ozone supplied with a very short (2.25 min) liquid contact time under continuous operation and reducing the need of further gas-liquid contacting equipment downstream from the MOBC. The increased performance of the MOBC ozonation reactor was benchmarked against a bubble column (BC) design and resulted in 20% increase on the rate of p-hydroxybenzoic acid (p-HBA) degradation, 75% increase in the rate of mineralization of p-HBA per mole of ozone consumed, and 3.2-fold increase in the rate of mineralization of p-HBA per mole of ozone supplied. This results from the very small size of bubbles (few hundreds of microns) and enhanced gas-liquid mass transfer and hold-up generated in the presence of small fluid pulsations and orifice baffles

Fast cation-exchange separation of proteins in a plastic microcapillary disc

A novel disposable adsorbent material for fast cation-exchange separation of proteins was developed based on plastic microcapillary films (MCFs). A MCF containing 19 parallel microcapillaries, each with a mean internal diameter of 142μm, was prepared using a melt extrusion process from an ethylene-vinyl alcohol copolymer (EVOH). The MCF was surface functionalised to produce a cation-exchange adsorbent (herein referred as MCF-EVOH-SP). The dynamic binding capacity of the new MCF-EVOH-SP material was experimentally determined by frontal analysis using pure protein solutions in a standard liquid chromatography instrument for a range of superficial flow velocities, u =5.5-27.7cms . The mean dynamic binding capacity for hen-egg lysozyme was found to be approximately 100μg for a 5m length film, giving a ligand binding density of 413ngcm . The dynamic binding capacity did not vary significantly over the range of u tested. The application of this novel material to subtractive chromatography was demonstrated for anionic BSA and cationic lysozyme at pH 7.2. The chromatographic separation of two cationic proteins, lysozyme and cytochrome-c, was also performed with a view to applying this technology to the analysis or purification of proteins. Future applications might include separation based on anion exchange and other modes of adsorption. © 2011 Elsevier B.V

Portable smartphone quantitation of prostate specific antigen (PSA) in a fluoropolymer microfluidic device

We present a new, power-free and flexible detection system named MCFphone for portable colorimetric and fluorescence quantitative sandwich immunoassay detection of prostate specific antigen (PSA). The MCFphone is composed by a smartphone integrated with a magnifying lens, a simple light source and a miniaturised immunoassay platform, the Microcapillary Film (MCF). The excellent transparency and flat geometry of fluoropolymer MCF allowed quantitation of PSA in the range 0.9 to 60. ng/ml with<7% precision in 13. min using enzymatic amplification and a chromogenic substrate. The lower limit of detection was further improved from 0.4 to 0.08. ng/ml in whole blood samples with the use of a fluorescence substrate. The MCFphone has shown capable of performing rapid (13 to 22. min total assay time) colorimetric quantitative and highly sensitive fluorescence tests with good %Recovery, which represents a major step in the integration of a new generation of inexpensive and portable microfluidic devices with commercial immunoassay reagents and off-the-shelf smartphone technology

Photo inactivation of virus particles in microfluidic capillary systems

It has long been established that UVC light is a very effective method for inactivating pathogens in a fluid, yet the application of UVC irradiation to modern biotechnological processes is limited by the intrinsic short penetration distance of UVC light in optically dense protein solutions. This experimental and numerical study establishes that irradiating a fluid flowing continuously in a microfluidic capillary system, in which the diameter of the capillary is turned to the depth of penetration of UVC light, uniquely treats the whole volume of the fluid to UVC light resulting in fast and effective inactivation of pathogens, with particular focus to virus particles. This was demonstrated by inactivating human herpes simplex virus type-1 (HSV-1, a large enveloped virus) on a dense 10% fetal calf serum solution in a range of fluoropolymer capillary systems, including a 0.75 mm and 1.50 mm internal diameter capillaries and a high-throughput MicroCapillary Film with mean hydraulic diameter of 206 μm. Up to 99.96% of HSV-1 virus particles were effectively inactivated with a mean exposure time of up to 10s, with undetectable collateral damage to proteins. The kinetics of virus inactivation matched well the results from a new mathematical model that considers the parabolic flow profile in the capillaries, and showed the methodology is fully predictable and scalable and avoids both the side effect of UVC light to proteins and the dilution of the fluid in current tubular UVC inactivation systems. This is expected to speed up the industrial adoption of non-invasive UVC virus inactivation in clinical biotechnology and biomanufacturing of therapeutic molecules

Direct photolysis of benzoylecgonine under UV irradiation at 254nm in a continuous flow microcapillary array photoreactor

Benzoylecgonine (BE) is the major metabolite of cocaine and a contaminant of emerging concern often detected in sewage treatment plant (STP) effluents and surface waters. In this study, an innovative microcapillary film (MCF) array photoreactor made of fluoropolymer material was used to determine the direct photolysis quantum yield of benzoylecgonine at 254 nm. The quantum yield of BE was found to be (6.22 ± 0.19) × 10-3 mol ein-1. The proposed methodology was validated by estimating the quantum yield of caffeine (7.48 10-4 ± 0.64) × 10-4 mol ein-1, which was found in agreement with results published in literature. The MCF uses a very small sample volume (in the order of 330μl per meter length of material) and allows extremely rapid photolysis with a short contact time ranging from a fraction of seconds to a few minutes. This new microfluidics approach presented in this study is particularly useful for determining the photochemical behavior of highly priced pharmaceuticals, illicit drugs, metabolites and uncommon or regulated substances

Illuminating brighter horizons: Photocatalysis for water remediation and energy production [Poster]

Illuminating brighter horizons: Photocatalysis for water remediation and energy production [Poster

Photocatalysis for water remediation and energy production [Poster]

Photocatalysis for water remediation and energy production [Poster

Hydroxypropyl methylcellulose as a novel tool for isothermal solution crystallization of micronized paracetamol

Pulmonary inhalation is increasingly being selected as a preferred route for the delivery of both small and large drug macromolecules for the treatment of a range of pathologies. The direct crystallization of micronized powders, in particular, paracetamol, remains difficult, as it requires the ability to work in high solution supersaturations where agglomeration, wall crusting, and heterogeneous nucleation hinder the control of crystal size and crystal size distribution. Polymer additives are recognized to help drive the production of a given polymorph or controlling crystal shape by means of adsorption on the crystal surface. With the aim of exploiting the polymer-control nucleation and growth of crystals for enhanced direct crystallization of micronized powders, batch cooling crystallization of paracetamol in water was carried out in the presence of 0.1-0.8% w/w hydroxypropyl methylcellulose (HPMC). In the presence of polymer, the onset of nucleation was delayed and extended beyond the cooling time of the solution, resulting in an isothermal cooling crystallization and the production of micronized paracetamol with a mean crystal size D50, in the range of 15-20 μm and an improved crystal size distribution. Equally, the rate generation of solution cloudiness was reduced by over 3-fold for the highest HPMC concentration tested, with no detectable impact on final product yield. The mechanisms for nucleation delay and growth inhibition by HPMC is unknown; however, a modification of crystals shape observed upon the addition of HPMC to the solution suggested it might be related to mass transfer limitations and intermolecular hydrogen bonding between the large HPMC and the small drug molecules. This technique can potentially be used for direct crystallization of other micronized drugs. © 2014 American Chemical Society

The effect of protein-precipitant interfaces and applied shear on the nucleation and growth of lysozyme crystals

This paper is concerned with the effect of protein–precipitant interfaces and externally applied shear on the nucleation and growth kinetics of hen egg-white lysozyme crystals. The early stages of microbatch crystallization of lysozyme were explored using both optical and confocal fluorescence microscopy imaging. Initially, an antisolvent (precipitant) was added to a protein drop and the optical development of the protein– precipitant interface was followed with time. In the presence of the water-soluble polymer poly(ethylene glycol) (PEG) a sharp interface was observed to form immediately within the drop, giving an initial clear separation between the lighter protein solution and the heavier precipitant. This interface subsequently became unstable and quickly developed within a few seconds into several unstable ‘fingers’ that represented regions of high concentration-gradient interfaces. Confocal microscopy demonstrated that the subsequent nucleation of protein crystals occurred preferentially in the region of these interfaces. Additional experiments using an optical shearing system demonstrated that oscillatory shear significantly decreased nucleation rates whilst extending the growth period of the lysozyme crystals. The experimental observations relating to both nucleation and growth have relevance in developing efficient and reliable protocols for general crystallization procedures and the controlled crystallization of single large high-quality protein crystals for use in X-ray crystallography