A Multi-tool Approach to Colloid Stability: SPOS and Separation Analysis

Turbitt, Cherie; O'hagan, Patrick; Hasapidis, Kerry; Pokrajac, Greg

doi:10.1081/dis-120015374

Cited by 2 publications

(4 citation statements)

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“…Thus, the question of flow stability depends on the magnitude of hydrodynamic force F H pushing particles together or apart depending on the magnitude of DLVO forces. As discussed in section 2.2.3 the total energy of interaction between particles has typically three extrema in the force: (69) repulsive barrier: (70) Aggregation in the primary minimum (permanent doublet formation) will occur when the hydrodynamic force, F H , can overcome first the attraction in the secondary minimum, -F s , and then the maximum repulsive force F r . But if F H exceeds the attractive force in the primary minimum (-F p ), the doublets will deflocculate.…”

Section: Criteria For Stability Of Flowing Colloid Suspensionsmentioning

confidence: 99%

“…The key difference between the SPOS method and the conventional instruments based on ensemble techniques is the high resolution and accuracy regarding small amounts of large particles besides the main population of primary particles. The SPOS technique has been already proved to give detailed information about aggregate size distribution and its change in time when particle aggregation occurs [67] [68] [69]. Furthermore, the SPOS method is often used to analyze small amount of large particles in silica slurries applied to chemical-mechanical polishing in the semiconductor industry [70] [71] [72] [73].…”

Section: Single-particle Optical Sizing (Spos)mentioning

confidence: 99%

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Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Georgieva

Dijkstra

Fricke

et al. 2010

Journal of Colloid and Interface Science

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We have investigated the phenomenon of flow-induced aggregation in highly concentrated colloidal dispersions exposed to strongly converging flow fields. This phenomenon is relevant not only for classical technical operations like coating, pumping or filtration, but also for the application of concentrated suspensions in upcoming processing technologies based on microfluidic devices. A ring-slit device (gap height 10 micrometers to 25 micrometers), which allows for a variation of flow kinematics in a wide range, has been developed in order to investigate this phenomenon. Various polymer dispersions with different particle surface properties have been used as model systems. Our experiments exclude, that channel clogging is due to retention of pre-existing aggregates, fouling or hydrodynamic bridging. Instead, we demonstrate that clogging of the microchannel is induced by hetero-coagulation between primary colloidal particles and micron-sized impurities present at concentrations on the order of 100 ppm to 1000 ppm. Clogging can occur even if the diameter of these impurities is less than a tenth of the gap height. Aggregation takes place in the converging flow field at the channel entrance, but not in the shear field within the slit. It can be suppressed by appropriate stabilization of the primary particles

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Section: Criteria For Stability Of Flowing Colloid Suspensionsmentioning

confidence: 99%

Section: Single-particle Optical Sizing (Spos)mentioning

confidence: 99%

Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Georgieva

Dijkstra

Fricke

et al. 2010

Journal of Colloid and Interface Science

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“…The stability of the nanocomposites immediately after synthesis was also analysed by transmittance profile while centrifuging analyses, performed with LUMiSizer equipment and software [35,36]. This methodology allows for the recording of the migration of the nanocomposites within the suspension while centrifugation is performed.…”

Section: Formulationmentioning

confidence: 99%

“…It is important to point out that the hydrodynamic diameters determined for the nanocomposites upon this technique based on particle velocity distribution for sedimentation phenomena were in good agreement with those values obtained by dynamic light scattering. The stability of the nanocomposites immediately after synthesis was also analysed by transmittance profile while centrifuging analyses, performed with LUMiSizer equipment and software [35,36]. This methodology allows for the recording of the migration of the nanocomposites within the suspension while centrifugation is performed.…”

Section: Formulationmentioning

confidence: 99%

Complex Polysaccharide-Based Nanocomposites for Oral Insulin Delivery

et al. 2020

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Polyelectrolyte nanocomposites rarely reach a stable state and aggregation often occurs. Here, we report the synthesis of nanocomposites for the oral delivery of insulin composed of alginate, dextran sulfate, poly-(ethylene glycol) 4000, poloxamer 188, chitosan, and bovine serum albumin. The nanocomposites were obtained by Ca2+-induced gelation of alginate followed by an electrostatic-interaction process among the polyelectrolytes. Chitosan seemed to be essential for the final size of the nanocomposites and there was an optimal content that led to the synthesis of nanocomposites of 400–600 nm hydrodynamic size. The enhanced stability of the synthesized nanocomposites was assessed with LUMiSizer after synthesis. Nanocomposite stability over time and under variations of ionic strength and pH were assessed with dynamic light scattering. The rounded shapes of nanocomposites were confirmed by scanning electron microscopy. After loading with insulin, analysis by HPLC revealed complete drug release under physiologically simulated conditions.

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A Multi-tool Approach to Colloid Stability: SPOS and Separation Analysis

Cited by 2 publications

References 1 publication

Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Clogging of microchannels by nano-particles due to hetero-coagulation in elongational flow

Complex Polysaccharide-Based Nanocomposites for Oral Insulin Delivery

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