Microfluidic in-line dynamic light scattering with a commercial fibre optic system

Torquato, Luis; Helaine, Nelson; Cui, Yufan; O’Connell, Róisín; Gummel, Jérémie; Robles, Eric S. J.; Jacob, David; Cabral, João T.

doi:10.1039/d3lc00062a

Cited by 8 publications

(8 citation statements)

References 51 publications

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“…These data show, perhaps, more clearly how the maximum for this physicochemical property shifts toward the equimolar ratio with increasing concentration. This increase in apparent translational diffusion coefficient has been observed and explained previously as DLS measures the mutual diffusion coefficient of micelles, monomers, and counterions in solution. − For uncharged micelles in solution, such as those formed by DDAO in neutral to basic conditions, the mutual diffusion coefficient equals the micellar diffusion as can be seen at all concentrations investigated from Figure b at 100% DDAO, where the near constant micelle radii from SANS for DDAO micelles with concentration are supported by little to no change in diffusion coefficient. However, for SDS micelles, which increase in polar radius from 16 Å at 10 mM to 25 Å at 50 mM, we observed an increase in apparent diffusion coefficient.…”

Section: Resultsmentioning

confidence: 99%

Concentration Dependent Asymmetric Synergy in SDS–DDAO Mixed Surfactant Micelles

Torquato,

Tyagi,

Sharratt

et al. 2024

Langmuir

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We investigate the structure and interactions of a model anionic/amphoteric mixed surfactant micellar system, namely, sodium dodecyl sulfate (SDS) and N,N-dimethyldodecylamine N-oxide (DDAO), employing SANS, FTIR, DLS, and pH measurements, in the range 0.1–100 mM total surfactant concentration and 0–100% DDAO. Increasing surfactant concentration is found to elongate the prolate ellipsoid micelles (R Polar ∼ 25–40 Å), accompanied by up to a 6-fold increase in micellar charge. The surfactant synergy, in terms of micellar charge and size, diffusion coefficient, solution pH, and headgroup interactions, was found to vary with concentration. At lower concentrations (≤50 mM), the SDS–DDAO ratio of maximum synergy is found to be asymmetric (at 65–85% DDAO), which is rationalized using regular solution theory, suggesting an equilibrium between Na+ dissociation, DDAO protonation, and counterion concentration. At higher concentrations, maximum synergy shifts toward the equimolar ratio. Overall, our study expands and unifies previous reports, providing a comprehensive understanding for this model, synergetic mixed micellar system.

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Section: Resultsmentioning

confidence: 99%

Concentration Dependent Asymmetric Synergy in SDS–DDAO Mixed Surfactant Micelles

Torquato,

Tyagi,

Sharratt

et al. 2024

Langmuir

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“…The system was capable of carrying out composition mapping measurements under flow with dynamically varying compositions, with integration times ranging from approximately 3 to 10 s. It was found that a glass capillary-connected device featuring a 1 mm internal diameter has certain advantages in terms of experimental robustness and ease of operation. Reducing the channel dimensions increases the shear gradients and requires high precision in optical alignment, and issues such as parasitic light refraction and reflections from the channel walls become more prominent [ 205 ].…”

Section: Scattering-based Detection Techniquesmentioning

confidence: 99%

“…Light Scattering [198,199,[201][202][203][204][205] • In the future, the integration of AI into these devices heralds a transformative change in signal processing, improving sensitivity and real-time analysis through machine learning. The automation of experimental optimization by AI will streamline processes and facilitate signal processing, guaranteeing the efficiency and reproducibility of measurements and experiments.…”

Section: Dynamicmentioning

confidence: 99%

On-Chip Photonic Detection Techniques for Non-Invasive In Situ Characterizations at the Microfluidic Scale

Kurdadze,

Lamadie,

Nehme

et al. 2024

Sensors

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Microfluidics has emerged as a robust technology for diverse applications, ranging from bio-medical diagnostics to chemical analysis. Among the different characterization techniques that can be used to analyze samples at the microfluidic scale, the coupling of photonic detection techniques and on-chip configurations is particularly advantageous due to its non-invasive nature, which permits sensitive, real-time, high throughput, and rapid analyses, taking advantage of the microfluidic special environments and reduced sample volumes. Putting a special emphasis on integrated detection schemes, this review article explores the most relevant advances in the on-chip implementation of UV–vis, near-infrared, terahertz, and X-ray-based techniques for different characterizations, ranging from punctual spectroscopic or scattering-based measurements to different types of mapping/imaging. The principles of the techniques and their interest are discussed through their application to different systems.

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“…Furthermore, it has been shown that the in-line integration of DLS equipment in the manufacturing process allows particle size distributions to be measured during the process. 14 However, due to its measurement principle, DLS is strongly influenced by large particles, making it difficult to obtain accurate particle size distributions for samples containing impurities such as agglomerates. In recent years, this challenge has been addressed by the nanoparticle tracking analysis (NTA), which measures particle size distributions by calculating the diffusion coefficient via tracking the movement of a single nanoparticle using optical video images and has attracted attention as a new analytical method to replace the conventional DLS method.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Dynamic light scattering (DLS) measurements are commonly used to assess the particle size distribution of liposomes. Furthermore, it has been shown that the in-line integration of DLS equipment in the manufacturing process allows particle size distributions to be measured during the process . However, due to its measurement principle, DLS is strongly influenced by large particles, making it difficult to obtain accurate particle size distributions for samples containing impurities such as agglomerates.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Quantitative Evaluation of a Drug during Liposome Preparation Using a Probe-Type Raman Spectrometer

Sato,

Haneishi,

Hisada

et al. 2024

Langmuir

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During the manufacturing process of liposome formulations, it is considered difficult to evaluate their physicochemical properties and biological profiles due to the complexity of their structure and manufacturing process. Conventional quality evaluation is labor-intensive and time-consuming; therefore, there was a need to introduce a method that could perform inline, real-time evaluation during the manufacturing process. In this study, Raman spectroscopy was used to monitor in real time the encapsulation of drugs into liposomes and the drug release, which are particularly important quality evaluation items. Furthermore, Raman spectroscopy combined with partial least-squares (PLS) analysis was used for quantitative drug evaluation to assess consistency with results from UV−visible spectrophotometry (UV), a common quantification method. The prepared various ciprofloxacin (CPFX) liposomes were placed in cellulose tubes, and a probe-type Raman spectrophotometer was used to monitor drug encapsulation, the removal of unencapsulated drug, and drug release characteristics in real time using a dialysis method. In the Raman spectra of the liposomes prepared by remote loading, the intensities of the CPFX-derived peaks increased upon drug encapsulation and showed a slight decrease upon removal of the unencapsulated drug. Furthermore, the peak intensity decreased more gradually during the drug release. In all Raman monitoring experiments, the discrepancy between quantified values of CPFX concentration in liposomes, as measured by Raman spectroscopy combined with partial least-squares (PLS) analysis, and those obtained through ultraviolet (UV) spectrophotometry was within 6.7%. The results revealed that the quantitative evaluation of drugs using a combination of Raman spectroscopy and PLS analysis was as accurate as the evaluation using UV spectrophotometry, which was used for comparison. These results indicate the promising potential of Raman spectroscopy as an innovative method for the quality evaluation of liposomal formulations.

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Microfluidic in-line dynamic light scattering with a commercial fibre optic system

Abstract: We report the coupling of dynamic light scattering (DLS) in microfluidics, using a contact-free fibre-optic system, enabling the under-flow characterisation of a range of solutions, dispersions, and structured fluids. The...

Cited by 8 publications

References 51 publications

Concentration Dependent Asymmetric Synergy in SDS–DDAO Mixed Surfactant Micelles

Concentration Dependent Asymmetric Synergy in SDS–DDAO Mixed Surfactant Micelles

On-Chip Photonic Detection Techniques for Non-Invasive In Situ Characterizations at the Microfluidic Scale

Real-Time Quantitative Evaluation of a Drug during Liposome Preparation Using a Probe-Type Raman Spectrometer

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