Monitoring cell cultivation in microfluidic segments by optical pH sensing with a micro flow-through fluorometer using dye-doped polymer particles

Funfak, Anette; Cao, Jialan; Wolfbeis, Otto S.; Martin, Karin; Köhler, J. Michael

doi:10.1007/s00604-008-0096-0

Cited by 44 publications

(28 citation statements)

References 22 publications

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“…It has found widespread use in applications, such as controlled release of drugs, cosmetics, inks, pigments protection of biological species for the removal of biological pollutants and so on [1]. More advanced uses of polymer nanoparticles includes the creation of nanostructured materials [2], pH sensing [3], polymer particles having metallic coating used for passive damping and energy-absorption systems [4] and selective gas adsorption [5]. The reinforcing fi ller materials such as carbon black, silica, iron, nickel particles, are usually used for rubber composites.…”

Section: Introductionmentioning

confidence: 99%

Polypropylene nanosphere: particle size and crystal structure

Paik

Kar

2009

Int J Plast Technol

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The high molecular weight polypropylene (PP) nanospheres (average particles size ~ 60 nm) were synthesized under controlled growth condition using Ziegler-Natta catalyst. The sizes of the PP particles were investigated through microscopy analysis. The size-dependent crystal structure and crystallinity were studied through X-Ray powder diffraction (XRD) and differential scanning calorimetry (DSC). At 25°C PP nanoparticles show higher crystallinity (~76%) compared to the micron sized PP particles (~59%). The rearrangement of polymer chains is the reason for the higher crystallinity of nanosphere PP particles. The periodic organization of PP chains inside the nanoparticles shows new peaks. These corroborate the presence of α-monoclinic phase. The α-crystalline lamella lengths of various particle sizes are calculated and found to be 14.5 nm for nanoparticles, whereas the same for the microsphere PP is 17.6 nm. The crystal domains consist of various sizes of α-monoclinic crystals. Moreover, the absence of γ-orthorhombic phase acknowledges that the PP nanospheres are composed of α-monoclinic crystal domains.

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Section: Introductionmentioning

confidence: 99%

Polypropylene nanosphere: particle size and crystal structure

Paik

Kar

2009

Int J Plast Technol

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“…These are favorable tools due to their sensitivity, selectivity, and capability of spatially resolved analyte and parameter monitoring. Fluorescent pH sensor layers were incorporated into microfluidic platforms using various methods such as photolithography, inkjet printing, dip, blade spin coating and used for chemical reaction and bioprocess engineering [7][8][9][10][11][12][13][14][15][16][17][18]. Because of its simplicity and sensitivity, fluorescence intensity detection is widely used in miniaturized systems.…”

mentioning

confidence: 99%

Development of microscopic time‐domain dual lifetime referencing luminescence detection for pH monitoring in microfluidic free‐flow isoelectric focusing

Poehler

Herzog

Suendermann

et al. 2015

Engineering in Life Sciences

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www.els-journal.com Page 3 Engineering in Life SciencesThis article is protected by copyright. All rights reserved. AbstractA lifetime-based ratiometric microscale pH sensor system and a fluorescence microscopic setup was developed for the in-line observation of pH in free-flow isoelectric focusing based on the principle of time-domain dual lifetime referencing (t-DLR). The t-DLR method has been developed for pH monitoring and various other applications in the fields of environmental monitoring and biotechnology. Here, we introduce the integration of pH sensor microstructures for t-DLR in microfluidic channels and the application of the t-DLR scheme for pH sensing in miniaturized electrophoretic procedures. The pH sensor was inkjet-printed on glass in rows with a length of 10 mm, a height of 404 ± 18 nm and a width of 371 ± 28 µm, and integrated into a microfluidic chip generated by a lasercutting and lamination technique. It had a working range from pH 4 to 8 with a pK A of 6.10 ± 0.01 and fast response times under 500 ms. The sensor was used for the in-line observation of the pH gradient during isoelectric focussing of the proteins β-lactoglobulin A, conalbumin and myoglobin and their identification by their isoelectric point (pI). The obtained pIs were in good agreement with literature data demonstrating the applicability of the pH sensor in microfluidic continuous separations.

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“…They can report about the changing pH or oxygen content by shifting or changing fluorescence which is caused by the physiological activity of cells [40]. This principle can be used for the monitoring of cell growth inside microfluid compartments as well as for the detection of toxicological responses of cell cultures in microfluid segments.…”

Section: Application Of Sensor Particlesmentioning

confidence: 99%

Droplet-Based Microfluidics as a Biomimetic Principle: From PCR-Based Virus Diagnostics to a General Concept for Handling of Biomolecular Information

Köhler

2012

Microdroplet Technology

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The ability of lithographic fabrication of microchannels for fluid transport on the one hand and the continuously decreasing critical dimensions during the development of microlithography over the last decades generated high expectations on the progress of automated processing of small amounts of substances. In particular, it was expected that large numbers of well distinguished chemical entities-atoms, molecules, nano particles-could become manipulated highly parallel and with high speed. This hope was fed by the imagination of an analogy between the electron transport in integrated circuits and the transport of chemical objects inside microfluidic networks. The experiences of the last both decades had shown that such ideas of a complete analogy are not realistic. The progress of handling of substance-coupled information is much slower as the progress of hard ware development in the electronic devices. But, beside this general disappointment, microfluidics is still promising the arise and growth-up of very important new strategies for organizing chemical systems at the microscale and for supplying functional interfaces between the complex information inside the world of molecules and particles on the one hand and electronic systems on the other hand.Whereas clouds of electrons are manipulated in digital electronic devices, clouds of molecules are transported through microchannels by a convective flow. But, the special conditions in microfluidics cause low Reynolds numbers which reflect the small ratio of channel diameter and volume flow rate to the viscous forces. The microfluidic conditions cause always a laminary structure of flow with steep flow velocity gradients and results in to very high fluidic dispersion of concentration signals if homogeneous fluids are applied. So, the principle high potential of J.M. K€ ohler

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Monitoring cell cultivation in microfluidic segments by optical pH sensing with a micro flow-through fluorometer using dye-doped polymer particles

Cited by 44 publications

References 22 publications

Polypropylene nanosphere: particle size and crystal structure

Polypropylene nanosphere: particle size and crystal structure

Development of microscopic time‐domain dual lifetime referencing luminescence detection for pH monitoring in microfluidic free‐flow isoelectric focusing

Droplet-Based Microfluidics as a Biomimetic Principle: From PCR-Based Virus Diagnostics to a General Concept for Handling of Biomolecular Information

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