Microfluidics of soft matter investigated by small-angle X-ray scattering

Otten, Alexander; Köster, Sarah; Struth, Bernd; Snigirev, Anatoly; Pfohl, Thomas

doi:10.1107/s0909049505013580

Cited by 64 publications

(57 citation statements)

References 11 publications

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“…For example, Haberkorn et al (2003) have studied the precipitation of bohemite and quinacridone by means of a turbulent mixer with a free-jet. Then, the advent of microfluidics with the subsequent use of micromixers permitted to obtain mixing in laminar regime based only on diffusion, a further increase in the time resolution, and a smaller sample volume consumed by the mixer (Otten et al 2005;Leng and Salmon 2009). Mainly, the geometry of mixers can be of two types, as shown in Fig.…”

Section: Fast Biological Reactions and Chemical Reactionsmentioning

confidence: 98%

“…This method is especially used for the study of nanoparticles formation, as a jet overcomes the fouling of the channel walls with nanoparticles and its subsequent clogging(Marmiroli et al al. (2007) examined the protein folding through a continuous flow micromixer starting from 300 ls Otten et al (2005). used a device based on hydrodynamic focusing in combination with a microdiffraction set up to study the intercalation of DNA into multilamellar cationic lipid layers and to study DNA mesophases(Pfohl et al 2007).…”

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confidence: 99%

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Time-resolved structure investigation with small angle X-ray scattering using scanning techniques

Amenitsch

Marmiroli

2011

Rend. Fis. Acc. Lincei

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Due to the availability of high-brilliance X-rays at synchrotron radiation facilities, small angle X-ray scattering (SAXS) measurements have become feasible for new sample environments, like microfluidics or aerosol systems. The combination of continuous flow methods and SAXS with spatial scanning enables in situ measurements of time-resolved structures at the nanoscale important for reactions kinetics and material synthesis and processing. In this review we present the latest achievements in terms of scanning SAXS along continuous flow mixing devices reducing the limit of time resolution at the microsecond range. This led to the determination of early stages of biological reactions like protein folding, and to gain insight into chemical reaction kinetics like nanoparticles formation. We also describe the coupling of scanning SAXS with aerosol generators, which is the only way to study the mechanisms for the self-assembly and aggregation of nanomaterials via the aerosol route. We finally give a brief outlook, as the potentiality of these techniques has not been fully exploited, leaving the possibility for further improvements in time resolution and sample consumption, for example with the new X-ray sources like Free Electron Lasers.

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Section: Fast Biological Reactions and Chemical Reactionsmentioning

confidence: 98%

mentioning

confidence: 99%

Time-resolved structure investigation with small angle X-ray scattering using scanning techniques

Amenitsch

Marmiroli

2011

Rend. Fis. Acc. Lincei

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“…With careful control of the operating conditions of coaxial EHDS (in this work 5.6 kV and 6 mL/h) we can produce pDNA/PEI polyplexes with the most appropriate structure which provide not only higher transfection efficiency but also better cell viability. A goal of our future research is to examine the polyplex formation process in the jet, and potentially the droplets, using in situ Small Angle Scattering experiments similar to those conducted in a microfluidic device by Otten et al (2005). In addition, other cell types will also be used to investigate the delivery efficiency of the pDNA/PEI polyplexed prepared by coaxial EHDS.…”

Section: ããmentioning

confidence: 98%

Coaxial electrohydrodynamic spraying of plasmid DNA/polyethylenimine (PEI) polyplexes for enhanced nonviral gene delivery

Fei

Lee

et al. 2009

Biotech & Bioengineering

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DNA/polyethylenimine (PEI) polyplexes are an important class of nonviral vectors. Although the conventional preparation method, bulk mixing, is straightforward, the formation of the DNA/PEI polyplexes is not well controlled. This work explores coaxial electrohydrodynamic spraying (EHDS) as a novel, alternative method to produce DNA/PEI polyplexes in a more controlled manner. Both pGFP/PEI and pSEAP/PEI polyplexes were produced by EHDS with a coaxial needle setup. The size of the polyplexes was determined using dynamic light scattering, and their ability to transfect NIH 3T3 cells was observed by using an inverted fluorescence microscope (pGFP) or quantified by measuring the activity level of alkaline phosphatase (pSEAP). At nitrogen to phosphate ratio (N/P) of 6.7, the polyplexes produced by coaxial EHDS had delivery efficiencies up to 2.6 times higher than those produced by bulk mixing. The N/P ratio and the structure of the EHDS used to make the polyplexes were crucial factors in determining the delivery efficiency.

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“…These chips are also known as lab-on-a-chip devices. Several successful microfluidic setups on SAXS stations have been presented in the literature, mostly focusing on mixing and/or high-throughput sample delivery (Pollack et al, 1999;Akiyama et al, 2002;Uzawa et al, 2004;Otten et al, 2005;Marmiroli et al, 2010;Toft et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

In situ microfluidic dialysis for biological small-angle X-ray scattering

Skou

Jensen

et al. 2014

J Appl Cryst

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Owing to the demand for low sample consumption and automated sample changing capabilities at synchrotron small-angle X-ray (solution) scattering (SAXS) beamlines, X-ray microfluidics is receiving continuously increasing attention. Here, a remote-controlled microfluidic device is presented for simultaneous SAXS and ultraviolet absorption measurements during protein dialysis, integrated directly on a SAXS beamline. Microfluidic dialysis can be used for monitoring structural changes in response to buffer exchange or, as demonstrated, protein concentration. By collecting X-ray data during the concentration procedure, the risk of inducing protein aggregation due to excessive concentration and storage is eliminated, resulting in reduced sample consumption and improved data quality. The proof of concept demonstrates the effect of halted or continuous flow in the microfluidic device. No sample aggregation was induced by the concentration process at the levels achieved in these experiments. Simulations of fluid dynamics and transport properties within the device strongly suggest that aggregates, and possibly even higher-order oligomers, are preferentially retained by the device, resulting in incidental sample purification. Hence, this versatile microfluidic device enables investigation of experimentally induced structural changes under dynamically controllable sample conditions.

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Microfluidics of soft matter investigated by small-angle X-ray scattering

Cited by 64 publications

References 11 publications

Time-resolved structure investigation with small angle X-ray scattering using scanning techniques

Time-resolved structure investigation with small angle X-ray scattering using scanning techniques

Coaxial electrohydrodynamic spraying of plasmid DNA/polyethylenimine (PEI) polyplexes for enhanced nonviral gene delivery

In situ microfluidic dialysis for biological small-angle X-ray scattering

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