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Bottlebrush polymer surfactants (BPSs), formed by the interfacial interactions between bottlebrush polymers (BPs) with poly(acrylic acid) side chains dissolved in an aqueous phase and amine-functionalized ligands dissolved in the oil phase, assemble and bind strongly to the fluid-fluid interface. The ratio between NBB (backbone degree of polymerization) and NSC (side chain degree of polymerization) defines the initial assembly kinetics, interface packing efficiency, and stress relaxation. The equilibrium interfacial tension (γ) increases when NBB < NSC, but decreases when NBB ≫ NSC, correlating to a pronounced change in the effective shape of the BPs from being spherical to worm-like structures. The apparent surface coverage (ASC), i.e., the interfacial packing efficiency, decreases as NBB increases. The dripping-to-jetting transition of an injected polymer solution, as well as fluorescence recovery after photobleaching experiments, revealed faster initial assembly kinetics for BPs with higher NBB. Euler buckling of BPS assemblies with different NBB values was used to characterize the stress relaxation behavior and bending modulus. The stress relaxation behavior was directly related to the ASC, reflecting the strong influence of macromolecular shape on packing efficiency. The bending modulus of BPSs decreases for NBB < NSC, but increased when NBB ≫ NSC, showing the effect of molecular architecture and multisite anchoring. All-liquid printed constructs with lower NBB BPs yielded more stable structured liquids, underscoring the importance of macromolecular packing efficiency at fluid interfaces. Overall, this work elucidates fundamental relationships between nanoscopic structures and macroscopic properties associated with various bottlebrush polymer architectures, which translate to the stabilization of all-fluidic printed constructs.

Ultrasmall gold nanoparticles (NPs) have revolutionized nanotechnology as they are an excellent starting substrate for the synthesis of organic‐inorganic hybrid materials with photonic or energy conversion applications, often with a responsive nature. However, ultrasmall NPs do not sustain plasmonic resonances, preventing their use in plasmon‐related applications. In the presented work, we show a method of chemical modification of ultrasmall gold nanoparticles in order to fabricate dynamically controlled plasmonic thin films. For this purpose, we used the Anti‐Galvanic Reduction process (AGR) to modify the surface of small gold nanoparticles, inducing plasmonic properties without notable size increases. Au@Ag NPs are then modified with liquid crystal‐like organic ligands. The obtained NPs can assemble into densely packed films with long‐range order and temperature‐dependent structural properties. Namely, we detect two, fully reversible phase transitions between the hexagonal and cubic symmetries. The combination of AGR and organic surface modifications enabled us to demonstrate the possibility of managing plasmonic properties in the thin film of ~2 nm diameter metallic NPs. [ABSTRACT FROM AUTHOR]

Chemotherapeutic treatment with conventional drug formulations pose numerous challenges, such as poor solubility, high cytotoxicity and serious off‐target side effects, low bioavailability, and ultimately subtherapeutic tumoral concentration leading to poor therapeutic outcomes. In the field of Nanomedicine, advances in nanotechnology have been applied with great success to design and develop novel nanoparticle‐based formulations for the treatment of various types of cancer. The approval of the first nanomedicine, Doxil® (liposomal doxorubicin) in 1995, paved the path for further development for various types of novel delivery platforms. Several different types of nanoparticles, especially organic (soft) nanoparticles (liposomes, polymeric micelles, and albumin‐bound nanoparticles), have been developed and approved for several anticancer drugs. Nanoparticulate drug delivery platform have facilitated to overcome of these challenges and offered key advantages of improved bioavailability, higher intra‐tumoral concentration of the drug, reduced toxicity, and improved efficacy. This review introduces various commonly used nanoparticulate systems in biomedical research and their pharmacokinetic (PK) attributes, then focuses on the various physicochemical and physiological factors affecting the in vivo disposition of chemotherapeutic agents encapsulated in nanoparticles in recent years. Further, it provides a review of the current landscape of soft nanoparticulate formulations for the two most widely investigated anticancer drugs, paclitaxel, and doxorubicin, that are either approved or under investigation. Formulation details, PK profiles, and therapeutic outcomes of these novel strategies have been discussed individually and in comparison, to traditional formulations. This article is categorized under:Nanotechnology Approaches to Biology > Cells at the NanoscaleDiagnostic Tools > In Vivo Nanodiagnostics and ImagingTherapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease [ABSTRACT FROM AUTHOR]

Soft nanoparticles (NPs) have recently emerged as a promising material for intracellular drug delivery. In this regard, NPs derived from polydimethylsiloxane (PDMS), an FDA approved polymer can be a suitable alternative to conventional soft NPs due to their intrinsic organelle targeting ability. However, the available synthesis methods of PDMS NPs are complicated or require inorganic fillers, forming composite NPs and compromising their native softness. Herein, for the first time, we present a simple, robust and scalable strategy for preparation of virgin sub-50 nm PDMS NPs at room temperature. The NPs are soft in nature, hydrophobic and about 30 nm in size. They are stable in physiological medium for two months and biocompatible. The NPs have been successful in delivering anticancer drug doxorubicin to mitochondria and nucleus of cervical and breast cancer cells with more than four-fold decrease in IC50 value of doxorubicin as compared to its free form. Furthermore, evaluation of cytotoxicity in reactive oxygen species detection, DNA fragmentation, apoptosis-associated gene expression and tumor spheroid growth inhibition demonstrate the PDMS NPs to be an excellent candidate for delivery of anticancer drugs in mitochondria and nucleus of cancer cells. [ABSTRACT FROM AUTHOR]

Targeted drug delivery based on polymeric nanoparticles has been a long‐standing interest in nanomedicine for its beneficial traits including controlled and localized drug release. Gas‐responsive polymers offer an advantageous platform and have been slowly gaining attention in spatially locating and displaying unique interactions of specific responsive chemical entities in polymeric chains with endogenous gaseous stimuli. In this review, we highlight recent developments in polymeric nanoformulations with stimulant chemical entities for gasotransmittors such as NO, CO, H2S, SO2, O2 and CO2 in enhancing efficacy in therapeutic interventions. We underline some challenges and limitations of exploring these systems for clinical applications, and how we can further tap into the potential of these emerging materials. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Chain exchange behaviors in self-assembled block copolymer (BCP) nanoparticles (NPs) at room temperature are investigated through observations of structural differences between parent and binary systems of BCP NPs with and without crosslinked domains. Pairs of linear diblock or triblock, and branched star-like polystyrene-poly(2-vinylpyridine) (PS-PVP) copolymers that self-assemble in a PVP-selective mixed solvent into BCP NPs with definite differences in size and self-assembled morphology are combined by diverse mixing protocols and at different crosslinking densities to reveal the impact of chain exchange between BCP NPs. Clear structural evolution is observed by dynamic light scattering and AFM and TEM imaging, especially in a blend of triblock + star copolymer BCP NPs. The changes are ascribed to the chain motion inherent in the dynamic equilibrium, which drives the system to a new structure, even at room temperature. Chemical crosslinking of PVP corona blocks suppresses chain exchange between the BCP NPs and freezes the nanostructures at a copolymer crosslinking density (CLD) of ∼9%. This investigation of chain exchange behaviors in BCP NPs having architectural and compositional complexity and the ability to moderate chain motion through tailoring the CLD is expected to be valuable for understanding the dynamic nature of BCP self-assemblies and diversifying the self-assembled structures adopted by these systems. These efforts may guide the rational construction of novel polymer NPs for potential use, for example, as drug delivery platforms and nanoreactors.

Magnetically-induced birefringence is usually low in molecular liquids owing to the low magnetic energy of molecules with respect to the thermal one. Despite this, it has been found that a mixture of dibutyl phosphate and propylamine at propylamine molar ratio (X) around 0.33 surprisingly gives an intense effect (∆n/λ ≈ −0.1 at 1 Tesla). In this paper the time- and intensity- response to the magnetic field of such mixture have been studied. It was found that the reaction to the magnetic field is unusually slow (from several minutes to hours) depending of the magnetic field intensity. On the basis of the data, the model of orientable dipoles dispersed in a matrix enables to interpret the magnetic field-induced self-assembly in terms of soft molecules-based nanostructures. The analogy with systems made of magnetically polarizable (solid or soft) particles dispersed in liquid carrier allows understanding, at the microscopic scale, the molecular origin and the supra-molecular dynamics involved in the observed behavior. The data present a novel phenomenon in liquid phase where the progressive building up/change of ordered and strongly interacting amphiphiles is driven by the magnetic field. [ABSTRACT FROM AUTHOR]

[Display omitted] • An operationally simple single-chain nanoparticle (SCNP) preparation method has been developed. • Intramolecularly crosslinked nanoparticles were formed by nucleophilic aromatic substitution in the dilute regime. • Single and double-folding polymers were achieved by two distinct crosslinkers. • SEC, DLS, and TEM characterizations verified compact formations of resulting nanoparticles. A facile approach is introduced to prepare single-chain nanoparticles (SCNPs) utilizing intramolecular crosslinking based on nucleophilic aromatic substitution reaction. The linear polymeric precursor comprising dichlorotriazine (DCT) moiety as a reactive pendant group is synthesized via ring-opening metathesis polymerization (ROMP). The reactive chlorine atoms on DCT motifs are substituted with a dithiol nucleophile in varying degrees to yield individually intramolecularly crosslinked polymer nanoparticles. In addition, double-collapse and modification reactions are exploited through the substitution reaction from the remaining unreacted chlorine atoms. A significant reduction in hydrodynamic volumes of the corresponding SCNPs is observed compared to their linear analogues. The obtained nanoparticles are characterized by size exclusion chromatography (SEC), proton nuclear magnetic resonance spectroscopy (1H NMR), diffusion-ordered spectroscopy (DOSY), dynamic light scattering (DLS), and transmission electron microscopy (TEM) techniques. [ABSTRACT FROM AUTHOR]

Abstract: The fundamentals and recent examples of applications of electrochemical techniques to study individual entities in solution are overviewed. Specifically, strategies that enable rapid and simple investigation of redox‐inactive and non‐catalytic particles are highlighted, broadening the range of entities that can be examined and, therefore, the value and capabilities of electrochemistry in the field. [ABSTRACT FROM AUTHOR]

Magnetically-induced birefringence is usually low in molecular liquids owing to the low magnetic energy of molecules with respect to the thermal one. Despite this, it has been found that a mixture of dibutyl phosphate and propylamine at propylamine molar ratio (X) around 0.33 surprisingly gives an intense effect (∆n/λ ≈ −0.1 at 1 Tesla). In this paper the time- and intensity- response to the magnetic field of such mixture have been studied. It was found that the reaction to the magnetic field is unusually slow (from several minutes to hours) depending of the magnetic field intensity. On the basis of the data, the model of orientable dipoles dispersed in a matrix enables to interpret the magnetic field-induced self-assembly in terms of soft molecules-based nanostructures. The analogy with systems made of magnetically polarizable (solid or soft) particles dispersed in liquid carrier allows understanding, at the microscopic scale, the molecular origin and the supra-molecular dynamics involved in the observed behavior. The data present a novel phenomenon in liquid phase where the progressive building up/change of ordered and strongly interacting amphiphiles is driven by the magnetic field.

For decades, cellulose nanocrystals (CNCs) have been produced by hydrolyzing the disordered cellulose chains of hierarchical fiber structures. These colloidal particles comprise highly ordered arrays of cellulose chains, impeding the physicochemical modifications of inner crystalline layers, which in turn restrict key colloidal properties, such as dispersion stability, functionalizability and charge, response to external fields, and transportation. Controlled oxidation of fibrils permits the partial disintegration of amorphous cellulose chains while maintaining contact with the crystalline body, yielding Janus-like nanoparticles with a needle-shaped crystalline body sandwiched between two disordered cellulose regions (hairs). We refer to these nanoparticles as hairy cellulose nanocrystalloids (HCNC). The protruding soft biopolymer brushes impart significant modifications to the colloidal properties of cellulose nanocrystals, promoting their functionality, charge, stability, and self-assembly. In this article, we embark on detailing how HCNCs behave more like soft nanoparticles as compared to rigid CNCs, explain their fundamental colloidal aspects, and provide a mechanistic overview on how HCNC may expand the horizon of next generation natural soft materials. [ABSTRACT FROM AUTHOR]

By simply blending two diblock copolymers with the same chemistry but with different compositions one is able to create well-defined larger soft ­nanoparticles as well as bimodal soft nanoparticles. Specifically, blending two diblock copolymers in a solvent good for both blocks followed by a gradual introduction of a non-solvent results in a mixed micelle, larger than their pure block-copolymer-forming micelles. The formation of well-defined larger micelle is due to the balance between the ability of the mixed micelles to assemble or merge in comparison to their pure diblock copolymer micelles. Evidently, the blending ratio, the mixing protocol, and non-solvent addition rate are crucial to achieving well-defined larger or bimodal micelles. [ABSTRACT FROM AUTHOR]

We report the electrocatalytic dehalogenation of trichloroethylene (TCE) by single soft nanoparticles in the form of Vitamin B12-containing droplets. We quantify the turnover number of the catalytic reaction at the single soft nanoparticle level. The kinetic data shows that the binding of TCE with the electro-reduced vitamin in the CoI oxidation state is chemically reversible. [ABSTRACT FROM AUTHOR]

Chemotherapeutic treatment with conventional drug formulations pose numerous challenges, such as poor solubility, high cytotoxicity and serious off-target side effects, low bioavailability, and ultimately subtherapeutic tumoral concentration leading to poor therapeutic outcomes. In the field of Nanomedicine, advances in nanotechnology have been applied with great success to design and develop novel nanoparticle-based formulations for the treatment of various types of cancer. The approval of the first nanomedicine, Doxil® (liposomal doxorubicin) in 1995, paved the path for further development for various types of novel delivery platforms. Several different types of nanoparticles, especially organic (soft) nanoparticles (liposomes, polymeric micelles, and albumin-bound nanoparticles), have been developed and approved for several anticancer drugs. Nanoparticulate drug delivery platform have facilitated to overcome of these challenges and offered key advantages of improved bioavailability, higher intra-tumoral concentration of the drug, reduced toxicity, and improved efficacy. This review introduces various commonly used nanoparticulate systems in biomedical research and their pharmacokinetic (PK) attributes, then focuses on the various physicochemical and physiological factors affecting the in vivo disposition of chemotherapeutic agents encapsulated in nanoparticles in recent years. Further, it provides a review of the current landscape of soft nanoparticulate formulations for the two most widely investigated anticancer drugs, paclitaxel, and doxorubicin, that are either approved or under investigation. Formulation details, PK profiles, and therapeutic outcomes of these novel strategies have been discussed individually and in comparison, to traditional formulations. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease., (© 2022 Wiley Periodicals LLC.)

We report the use of single Vitamin B12 nanodroplets to mediate the reduction of oxygen in neutral buffer. Electron transfer to single Vitamin B12 nanodroplets is observed using the nano-impacts method and shown to be quantitative. The mechanism of mediated oxygen reduction by single VB12 droplets is revealed as via both CoII and CoI reduced from CoIII in VB12 through one or two electron transfer followed by the four-electron reduction of oxygen. [ABSTRACT FROM AUTHOR]

The agent Panavir possesses versatile antiviral, anti-inflammatory, and analgesic effects, which still have not been explained at the molecular level. Here, we propose a simple physicochemical model of Panavir nanoparticles, which allows one to explain its effects by the mechanical activation of cells, including those of the immune system. Thus, there is no need for binding of the Panavir particles to any supramolecular chiral receptor for manifestation of its all known effects. [ABSTRACT FROM AUTHOR]

Highlights: [•] Electrokinetic theory furnishes the soft-sphere electrophoretic mobility in polyelectrolyte gels. [•] Mobility is sensitive to the gel charge and permeability. [•] Mobility is sensitive to the core dielectric constant when gels are charged. [•] Matlab routines are available for parametric studies and interpretation of experiments. [Copyright &y& Elsevier]

Abstract: We report here the development of stable aqueous suspensions of superparamagnetic iron oxide nanoparticles stabilized with unmodified polyethylene glycol (PEG) at four molecular weights (2000, 4000, 6000 and 10,000Da) and several PEG/iron ratios. The obtained ferrofluid was an opaque dispersion of pH ≈ 5.0 with an iron content ranging from 15mgmL−1 to 17mgmL−1 (depending on the molecular weight of the PEG used), and a ζ-potential of 20±2mV. The diameter of uncoated particles determined by X-ray diffraction was ≈12nm; a value that ensures superparamagnetic properties and suitability for use in hyperthermic therapy. When coated and determined by dynamic light scattering, the hydrodynamic diameter of the particles was 56nm for the lowest PEG/iron ratio. Thermogravimetric analysis showed that the content of PEG in the ferrofluid ranged from 6.5% to 23.8%, depending on the different molecular weights and amount of PEG used. The interaction of PEG with magnetite is probably due to dipole–cation binding between the ether group of the polymer and the positive charge of magnetite. As regards physical stability, the ferrofluid was stable in the absence of salt over a period of more than two years. [Copyright &y& Elsevier]

Abstract: A theoretical model is presented to describe the spatiotemporal behavior of complex liquid–solid interfaces bordered by the contact line formed between liquid-like particle and solid-rough substrate. The analysis helps us to determine the soft-nanoparticle adhesion. When the interfacial temperature is above the glass transition and the substrate is rough, we find that surface forces can change by orders of magnitude depending on the temperature, contact time, and particle size varying from atoms to microns. The critical surface tension of solid substrates and the temperature-dependent structural relaxation of soft nanoparticles are shown to have significant effects on the size-dependent adhesion. [Copyright &y& Elsevier]

Self-assembly of amphiphilic macromolecules has provided an advantageous platform to address significant issues in a variety of areas, including biology. Such soft nanoparticles with a hydrophobic core and hydrophilic corona, referred to as micelles, have been extensively investigated for delivering lipophilic therapeutics by physical encapsulation. Polymeric vesicles or polymersomes with similarities in morphology to liposomes continue to play an essential role in understanding the behavior of cell membranes and, in addition, have offered opportunities in designing smart nanoformulations. With the evolution in synthetic methodologies to macromolecular precursors, the construction of such assemblies can now be modulated to tailor their properties to match desired needs. This review brings into focus the current state-of-the-art in the design of polymersomes using amphiphilic miktoarm star polymers through a detailed analysis of the synthesis of miktoarm star polymers with tuned lengths of varied polymeric arms, their self-assembly, and applications in drug delivery.

Chain exchange behaviors in self-assembled block copolymer (BCP) nanoparticles (NPs) at room temperature are investigated through observations of structural differences between parent and binary systems of BCP NPs with and without crosslinked domains. Pairs of linear diblock or triblock, and branched star-like polystyrene-poly(2-vinylpyridine) (PS-PVP) copolymers that self-assemble in a PVP-selective mixed solvent into BCP NPs with definite differences in size and self-assembled morphology are combined by diverse mixing protocols and at different crosslinking densities to reveal the impact of chain exchange between BCP NPs. Clear structural evolution is observed by dynamic light scattering and AFM and TEM imaging, especially in a blend of triblock + star copolymer BCP NPs. The changes are ascribed to the chain motion inherent in the dynamic equilibrium, which drives the system to a new structure, even at room temperature. Chemical crosslinking of PVP corona blocks suppresses chain exchange between the BCP NPs and freezes the nanostructures at a copolymer crosslinking density (CLD) of ∼9%. This investigation of chain exchange behaviors in BCP NPs having architectural and compositional complexity and the ability to moderate chain motion through tailoring the CLD is expected to be valuable for understanding the dynamic nature of BCP self-assemblies and diversifying the self-assembled structures adopted by these systems. These efforts may guide the rational construction of novel polymer NPs for potential use, for example, as drug delivery platforms and nanoreactors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Li, Davis, Mays, Wang and Kilbey.)

Soft nanoparticles continue to offer a promising platform for the encapsulation and controlled delivery of poorly water-soluble drugs and help enhance their bioavailability at targeted sites. Linear amphiphilic block copolymers are the most extensively investigated in formulating delivery vehicles. However, more recently, there has been increasing interest in utilizing branched macromolecules for nanomedicine, as these have been shown to lower critical micelle concentrations, form particles of smaller dimensions, facilitate the inclusion of varied compositions and function-based entities, as well as provide prolonged and sustained release of cargo. In this review, it is aimed to discuss some of the key variables that are studied in tailoring branched architecture-based assemblies, and their influence on drug loading and delivery. By understanding structure-property relationships in these formulations, one can better design branched star polymers with suitable characteristics for efficient therapeutic interventions. The role played by polymer composition, chain architecture, crosslinking, stereocomplexation, compatibility between polymers and drugs, drug/polymer concentrations, and self-assembly methods in their performance as nanocarriers is highlighted., (© 2021 Wiley-VCH GmbH.)

Architectural complexity has played a key role in enhancing the efficacy of nanocarriers for a variety of applications, including those in the biomedical field. With the continued evolution in designing macromolecules-based nanoparticles for drug delivery, the combination approach of using important features of linear polymers with dendrimers has offered an advantageous and viable platform. Such nanostructures, which are commonly referred to as telodendrimers, are hybrids of linear polymers covalently linked with different dendrimer generations and backbones. There is considerable variety in selection from widely studied linear polymers and dendrimers, which can help tune the overall composition of the resulting hybrid structures. This review highlights the advances in articulating syntheses of these macromolecules, and the contributions these are making in facilitating therapeutic administration. Limited progress has been made in the design and synthesis of these hybrid macromolecules, and it is through an understanding of their physicochemical properties and aqueous self-assembly that one can expect to fully exploit their potential in drug delivery. [ABSTRACT FROM AUTHOR]

Delivering active pharmaceutical agents to disease sites using soft polymeric nanoparticles continues to be a topical area of research. It is becoming increasingly evident that the composition of amphiphilic macromolecules plays a significant role in developing efficient nanoformulations. Branched architectures with asymmetric polymeric arms emanating from a central core junction have provided a pivotal venue to tailor their key parameters. The build-up of miktoarm stars offers vast polymer arm tunability, aiding in the development of macromolecules with adjustable properties, and allows facile inclusion of endogenous stimulus-responsive entities. Miktoarm star-based micelles have been demonstrated to exhibit denser coronae, very low critical micelle concentrations, high drug loading contents, and sustained drug release profiles. With significant advances in chemical methodologies, synthetic articulation of miktoarm polymer architecture, and determination of their structure-property relationships, are now becoming streamlined. This is helping advance their implementation into formulating efficient therapeutic interventions. This review brings into focus the important discoveries in the syntheses of miktoarm stars of varied compositions, their aqueous self-assembly, and contributions their formulations are making in advancing the field of drug delivery. [ABSTRACT FROM AUTHOR]

The behavior of nanogels in suspension can be dramatically affected by the grafting of a canopy of end-tethered polymer chains. The architecture of the interfacial layer, defined by the grafting density and length of the polymer chains, is a crucial parameter in defining the conformation and influencing the dynamics of the grafted chains. However, the influence of this architecture when the core substrate is itself soft and mobile is complex; the dynamics of the core influences the dynamics of the tethered chains, and, conversely, the dynamics of the tethered chains can influence the dynamics of the core. Here, poly(styrene) (PS) particles were functionalized with poly(methyl acrylate) (PMA) chains and swollen in a common solvent. NMR relaxation reveals that the confinement influences the mobility of the grafted chain more prominently for densely grafted short chains. The correlation time associated with the relaxation of the PMA increased by more than 20% when the grafting density increased for short chains, but for less than 10% for long chains. This phenomenon is likely due to the steric hindrance created by the close proximity to the rigid core and of the neighboring chains. More interestingly, a thick layer of a densely grafted PMA canopy efficiently increases the local mobility of the PS cores, with a reduction of the correlation time of more than 30%. These results suggest an interplay between the dynamics of the core and the dynamics of the canopy. [ABSTRACT FROM AUTHOR]

This study reports a general scenario for the out-of-equilibrium features of collapsing polymeric architectures. We use molecular dynamics simulations to characterize the coarsening kinetics, in bad solvent, for several macromolecular systems with an increasing degree of structural complexity. In particular, we focus on: flexible and semiflexible polymer chains, star polymers with 3 and 12 arms, and microgels with both ordered and disordered networks. Starting from a powerful analogy with critical phenomena, we construct a density field representation that removes fast fluctuations and provides a consistent characterization of the domain growth. Our results indicate that the coarsening kinetics presents a scaling behaviour that is independent of the solvent quality parameter, in analogy to the time–temperature superposition principle. Interestingly, the domain growth in time follows a power-law behaviour that is approximately independent of the architecture for all the flexible systems; while it is steeper for the semiflexible chains. Nevertheless, the fractal nature of the dense regions emerging during the collapse exhibits the same scaling behaviour for all the macromolecules. This suggests that the faster growing length scale in the semiflexible chains originates just from a faster mass diffusion along the chain contour, induced by the local stiffness. The decay of the dynamic correlations displays scaling behavior with the growing length scale of the system, which is a characteristic signature in coarsening phenomena. [ABSTRACT FROM AUTHOR]

In recent years, rapid progress in the field of single-entity electrochemistry (SEE) has opened a novel exploratory area in the field of analytical and electrochemistry. SEE is a method of studying the behavior of particles at the single particle level, which yields important information on the diffusion coefficient, individual particle size, size distribution, catalytic activity, collision frequency, and internal substances of the particles. Various types of particles have been studied through SEE. Among them, this review focuses on the results of analyzing soft particles (cells, proteins, viruses, liposomes, enzymes, vesicles, emulsion droplets, micelles, carbonaceous nanomaterials, and others). We introduce the various electrochemical techniques used in SEE and discuss important concepts and equations that must be known to apply SEE. We also introduce the results of recent research on several important soft particles. Finally, the potential applications in areas such as sensors, materials, catalysts, energy, and biomedicine, as well as the trends of related works are described. In the future, research on soft particle analysis using SEE is expected to increase rapidly, and this review is expected to be a valuable reference for researchers in the field. • Soft particle detection using Single-Entity Electrochemistry (SEE) is introduced. • Current signal types occurring in soft particle-electrode collision are introduced. • Basic concepts and formulas for single soft particle analysis are introduced. • SEE results of soft particles (e.g., red blood cells, proteins) are introduced. [ABSTRACT FROM AUTHOR]

Branched architectures with asymmetric polymeric arms provide an advantageous platform for the construction of tailored nanocarriers for therapeutic interventions. Simple and adaptable synthetic methodologies to amphiphilic miktoarm star polymers have been developed in which spatial location of reactive oxygen species (ROS) and glutathione (GSH) responsive entities is articulated to be on the corona shell surface or inside the core. The design of such architectures is facilitated through versatile building blocks and selected combinations of ring-opening polymerization, Steglich esterification, and alkyne-azide click reactions. Soft nanoparticles from aqueous self-assembly of these stimuli responsive miktoarm stars have low critical micelle concentrations and high drug loading efficiencies. Partial corona shedding upon response to ROS is accompanied by an increase in drug release, without significant changes to overall micelle morphology. The location of the GSH responsive unit at the core leads to micelle disassembly and complete drug release. Curcumin loaded soft nanoparticles show higher efficiencies in preventing ROS generation in extracellular and cellular environments, and in ROS scavenging in human glioblastoma cells. The ease in synthetic elaboration and an understanding of structure-property relationships in stimuli responsive nanoparticles offer a facile venue for well-controlled drug delivery, based on the extra- and intracellular concentrations of ROS and GSH., (© 2020 Wiley‐VCH GmbH.)

Amphiphilic architectural polymers of tunable compositions self-assemble into soft nanoparticles of varied stability that is dependent on the number of poly(ethylene glycol) tails. Cryo -electron microscopy- and freeze-fracture -technique-based evaluations of their internal structure display morphologies unlike those of conventional block-copolymer-based micelles, with a uniform and homogeneous composition that strongly influences drug-specific encapsulation and release characteristics. The suberanilohydroxamic acid (SAHA) and Temozolomide drug combination (with or without telodendrimer loading) shows synergistic effects in glioblastoma, and curcumin-loaded DP 3 telodendrimers reduce neurite loss in cisplatin-treated dorsal root ganglia explants.

Tissue engineering has emerged as an important research area that provides numerous research tools for the fabrication of biologically functional constructs that can be used in drug discovery, disease modeling, and the treatment of diseased or injured organs. From a materials point of view, scaffolds have become an important part of tissue engineering activities and are usually used to form an environment supporting cellular growth, differentiation, and maturation. Among various materials used as scaffolds, hydrogels based on natural polymers are considered one of the most suitable groups of materials for creating tissue engineering scaffolds. Natural hydrogels, however, do not always provide the physicochemical and biological characteristics and properties required for optimal cell growth. This review discusses the properties and tissue engineering applications of widely used natural hydrogels. In addition, methods of modulation of their physicochemical and biological properties using soft nanoparticles as fillers or reinforcing agents are presented., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We present nanocomposite materials formed by using glassy star-shaped polymers as nanofillers and dispersing them in soft matrices. The resulting "architecturally engineered" polymer nanocomposites structurally reside between the linear homopolymer blends and the conventional polymer nanocomposites with inorganic fillers, inducing reinforcement, which can be as strong as that of solid nanoparticles, or softening depending on the compactness and concentration of the nanoparticles. Such behavior can be traced back to the dynamical features at the local segmental and the chain level, which we investigated using neutron scattering over a wide range of time and length scales in the glassy and melt states of the nanocomposites. The local and segmental dynamics as well as the degree of chain-chain entanglements are all modified by the star-shaped fillers. The presented approach to tuning the physical properties of all-polymer-based nanocomposites is readily adaptable to other polymer architectures with immediate applications in numerous areas including gas separation membranes, tissue engineering, drug delivery, and functional coatings.

Back Cover: Blending two block copolymer solutions with the same chemistry, but different compositions, and in turn adding non‐solvent, i.e., water results in larger or bimodal soft‐nanoparticles. Evidently, the blending ratio, the mixing protocol and non‐solvent addition rate are crucial to achieving well‐defined larger or bimodal soft nanoparticles. Further details can be found in the article by X. Ye, and B. Khomami* on page 1760. [ABSTRACT FROM AUTHOR]

We report the electrocatalytic dehalogenation of trichloroethylene (TCE) by single soft nanoparticles in the form of Vitamin B12 -containing droplets. We quantify the turnover number of the catalytic reaction at the single soft nanoparticle level. The kinetic data shows that the binding of TCE with the electro-reduced vitamin in the Co(I) oxidation state is chemically reversible., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the use of single Vitamin B12 nanodroplets to mediate the reduction of oxygen in neutral buffer. Electron transfer to single Vitamin B12 nanodroplets is observed using the nano-impacts method and shown to be quantitative. The mechanism of mediated oxygen reduction by single VB12 droplets is revealed as via both Co(II) and Co(I) reduced from Co(III) in VB12 through one or two electron transfer followed by the four-electron reduction of oxygen., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A previously reported nanoparticle formed through the self-assembly of common food constituents (amylose, protein, and fatty acids) was shown to have the capacity to carry a sparingly soluble small molecule (1-naphthol) in a dispersed system. Potentiometric titration showed that 1-naphthol locates in the lumen of the amylose helix of the nanoparticle. This finding was further supported by calorimetric measurements, showing higher enthalpies of dissociation and reassociation in the presence of 1-naphthol. Visually, the 1-naphthol-loaded nanoparticle appeared to be well-dispersed in aqueous solution. Molecular dynamics simulation showed that the self-assembly was favorable, and at 500 ns, the 1-naphthol molecule resided in the helix of the amylose lumen in proximity to the hydrophobic tail of the fatty acid. Thus, sparingly soluble small molecules, such as some nutraceuticals or drugs, could be incorporated and delivered by this soft nanoparticle carrier.