A combined small-angle scattering study of a chemical reaction at specific sites and reaction-induced self-assembly as a problem in open non-equilibrium phenomena

Hashimoto, Takeji; Tanaka, Hirokazu; Koizumi, Satoshi; Naka, Kensuke; Chujo, Yoshiki

doi:10.1107/s0021889807003445

Cited by 18 publications

(28 citation statements)

References 12 publications

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“…A quartz capillary cell (2 mm diameter; Hilgenberg GmbH) was used for all measurements. A model of a PTX–BSA-liposome is considered wherein a number of PTX–BSA molecules are entrapped in liposomes as a template, as illustrated in Figure S1.(33) A PTX–BSA-liposome is modeled with the following equations…”

Section: Methodsmentioning

confidence: 99%

Preparation, Characterization, and in Vitro/in Vivo Evaluation of Paclitaxel-Bound Albumin-Encapsulated Liposomes for the Treatment of Pancreatic Cancer

Okamoto¹,

Taguchi

Saeedi³

et al. 2019

ACS Omega

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Paclitaxel (PTX)-loaded liposomes were developed with the goal of enhancing the effects of cancer treatment. Although loading substances into the lipid membrane of liposome cause some destabilization of the lipid membrane, PTX was nearly exclusively embedded in the lipid membrane of liposomes, due to its low water solubility. Hydrophobic drugs can be encapsulated into the inner core of bovine serum albumin (BSA)-encapsulated liposomes (BSA-liposome) via noncovalent binding to albumin. Since PTX is able to noncovalently bind to albumin, we attempted to prepare PTX-loaded BSA-liposome (PTX–BSA-liposome). The amount of PTX loaded in the BSA-liposome could be increased substantially by using ethanol, since ethanol increases PTX solubility in BSA solutions via prompting the binding PTX to BSA. On the basis of the results of transmission electron microscopy and small-angle X-ray scattering, PTX–BSA-liposome formed unilamellar vesicles that were spherical in shape and the PTX was encapsulated into the inner aqueous core of the liposome as a form of PTX–BSA complex. In addition, the PTX–BSA-liposome, as well as nab-PTX, showed cytotoxicity against human pancreatic cancer cells, AsPC-1 cells, in a PTX concentration-dependent manner. The in vivo antitumor effect of PTX–BSA-liposomes was also observed in a mouse model that had been subcutaneously inoculated with pancreatic cancer cells by virtue of its high accumulation at the tumor site via the enhanced permeability retention effect. These results suggest that PTX–BSA-liposomes have the potential for serving as a novel PTX preparation method for the treatment of pancreatic cancer.

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Section: Methodsmentioning

confidence: 99%

Preparation, Characterization, and in Vitro/in Vivo Evaluation of Paclitaxel-Bound Albumin-Encapsulated Liposomes for the Treatment of Pancreatic Cancer

Okamoto¹,

Taguchi

Saeedi³

et al. 2019

ACS Omega

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“…The first term of the right-hand side (rhs) of eq is responsible for the scattering from the homogeneous cluster with ⟨η 2 ⟩ = 0, while the second term for the scattering from the SLD fluctuations within the cluster. In our earlier paper, we neglected the term K by setting K = 1, which affects only the evaluation of the absolute value of ⟨η 2 ⟩/(Δ p 0 ) 2 . In the case when the cluster size is infinitely large, ( q ) = δ( q ), so that eq reduces to and thereby to the equation originally given by the DB theory.…”

Section: Theoretical Background For Analyses Of Scattering Profilesmentioning

confidence: 99%

Hierarchically Self-Organized Dissipative Structures of Filler Particles in Poly(styrene-ran-butadiene) Rubbers

et al. 2017

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We elucidated the spatial distribution of filler particles in cross-linked poly(styrene-ran-butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. Two types of fillers and two types of SBR were used to prepare four kinds of the fillers/rubbers composites to investigate effects of specific polymer/filler interactions on the hierarchically self-organized dissipative structures under a given processing condition. The dispersion structures of the filler particles were explored by using the combined small-angle scattering (CSAS) method, which enables the exploration of the structures existing over the wide length scale ranging from ∼6 nm to ∼20 μm. The measured CSAS profiles were analyzed by using a newly developed scattering theory on fractal structures built up by the “cluster” as their lower cutoff objects. This cluster is composed of a few aggregates, defined as the fused primary filler particles, bound by the SBR chains. The scattering from the cluster having characteristic internal structures built up by the fillers and the SBR chains was theoretically formulated by generalizing the Debye–Bueche fluctuation theory for infinite space to the theory for a “confined space” relevant to the cluster size. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels as detailed in the text. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.

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“…The corresponding scattering intensity at nonzero q values thus contains an additional contribution from the form factor of the cluster; moreover, the SHS structure factor S SHS/inf needs to be convoluted with such a cluster shape factor to account for the confinement effect. 50 The reduced scattering intensity (with respect to V ir and…”

Section: = +mentioning

confidence: 99%

Mechanism of Hierarchical Structure Formation of Polymer/Nanoparticle Hybrids

et al. 2016

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Exploiting the assembly of metallic nanoparticles (NPs) in their hybrids with polymers is an important task for creating new properties or functionalities via collective interactions or dynamics of the constituents. In this work, we present a detailed study of the process and mechanism of the reactioninduced hierarchical assembly of NPs in the hybrid wherein the metallic Pd NPs were synthesized and their numbers in the system increased with time by reducing the metal precursor, Pd(acac) 2 , originally dissolved uniformly in the solution of poly(2-vinylpyridine) (P2VP) with benzyl alcohol (BA) as a solvent and reduction agent. The time-resolved small-angle X-ray scattering (SAXS) experiment using synchrotron radiation revealed that the structural evolution process from the beginning of NP formation to the establishment of a fractal structure built up by the clusters of Pd NPs was constituted of four distinct stages, Stages 1−4, governed by the increasing overall NP volume fraction (ϕ overall ) and hence by the increasing reduction time. At Stage 1, the NPs were uniformly distributed in the matrix of P2VP and BA with negligible interparticle interaction due to the low particle volume fraction (ϕ overall ≤ ca. 3 × 10 −4 ). The structural evolution advanced to Stage 2 when ϕ overall was increased above 3 × 10 −4 . In this stage, the NPs experienced the sticky hard sphere (SHS) type attractive interaction, and as a consequence the NPs underwent a phase separation into a particle-poor phase (Phase I) and a particle-rich phase (Phase II) strikingly even in such a small ϕ overall . The net interparticle attraction created the dynamic aggregates distributed uniformly within Phase II. As the ϕ overall continued to increase to ca. 4.7 × 10 −4 , the structural development entered Stage 3, in which the dynamic aggregates started to form a higher-order organization, generating a larger-scale heterogeneity in Phase II. The structure developed at Stage 3 served as a precursor directing the subsequent formation of the large-scale mass-fractal network built up by the static clusters of NPs within Phase II at Stage 4. The particles within the clusters were proposed to be bridged by the P2VP chains due to pyridine−Pd coordination interaction.

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A combined small-angle scattering study of a chemical reaction at specific sites and reaction-induced self-assembly as a problem in open non-equilibrium phenomena

Cited by 18 publications

References 12 publications

Preparation, Characterization, and in Vitro/in Vivo Evaluation of Paclitaxel-Bound Albumin-Encapsulated Liposomes for the Treatment of Pancreatic Cancer

Preparation, Characterization, and in Vitro/in Vivo Evaluation of Paclitaxel-Bound Albumin-Encapsulated Liposomes for the Treatment of Pancreatic Cancer

Hierarchically Self-Organized Dissipative Structures of Filler Particles in Poly(styrene-ran-butadiene) Rubbers

Mechanism of Hierarchical Structure Formation of Polymer/Nanoparticle Hybrids

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