Large, hydrophilic polyoxoanions with high solubility in water and/or other polar solvents demonstrate unique solution behavior by self-assembling into single layer, hollow, spherical "blackberry" ...structures, which is obviously different from small, simple ions. These macroions cannot be treated as insoluble colloidal suspensions because they form stable "real solutions". Counterion-mediated attraction is considered as the main driving force for the self-assembly behavior. The size disparity between the macroions and their counterions results in macroion-counterion pairing which leads to the inter-macroanionic attraction. The blackberries, with robust membranes semi-permeable to cations, can adjust their size accurately and reversibly in response to the change of solvent polarity and charge density of individual macroions. The inorganic macroions with well-defined size, shape, mass, charge density, but no intramolecular interactions, are ideal model systems to study the intermolecular interactions in polyelectrolyte and bio-macromolecular solutions. The blackberry structures show certain similarities to spherical viral capsids, from the overall structure to the formation kinetics. More amazingly, these inorganic macroions demonstrate some features usually believed to belong only to complex biological molecules, such as the self-recognition in dilute solutions. Meanwhile, polyoxometalates-based organic-inorganic hybrid materials demonstrate amphiphilic properties by self-assembling into vesicles and reverse vesicles in polar and non-polar solvents, respectively, and form monolayer at the water/air interface. Different from conventional amphiphiles, these hybrids show pH-dependent and counterion-dependent self-assembly behaviors with controllable functionality, e.g. fluorescence and catalytic activity, due to the high and tunable charges and the functionalities of POM polar head groups.
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Thermoplastic elastomers (TPEs) have found use in a wide range of applications, such as adhesives, elastomers, coatings, fibers, and in additive manufacturing techniques such as 3D ...printing. Despite their omnipresence, the need for advanced TPEs with adaptive properties is continuously growing. Along with a brief historical introduction, this review presents an overview of typical structure-property relationships for various TPEs and discusses the design principles of TPEs from a synthetic chemistry perspective. Recent advances in TPEs with different macromolecular architectures, including linear ABA triblock copolymers, ABC triblock terpolymers, multiblock copolymers, star copolymers, graft copolymers, bottlebrush polymers, and hyperbranched polymers are reviewed. Service temperatures and mechanical properties of the different materials are compared in each section. Incorporating various supramolecular interactions into different macromolecular architectures as a means to further extend the range of TPE applications is also discussed. Future opportunities for TPE research in both academia and industry are addressed as perspectives.
A polyoxometalate hosting Ag
+
, AgP
5
W
30
O
110
14−
, has been studied for its sustained and controlled release of Ag
+
triggered by Na
+
replacement at room temperature for long-lasting ...bacteriostasis, whose antibacterial activity is not eliminated after repeated exposure tests because of the protection of Ag
+
by the polyoxometalate skeleton.
The release of Ag
+
confined in the cavities of nanoscale inorganic clusters can be selectively triggered by the Na
+
present in solutions or biological media for long-lasting bacteriostasis.
Developing strategies against the antibiotic resistance is a major global challenge for public health. Here, we report the synergy of the combination of Preyssler-type polyoxometalates (POMs) ...(NaP5W30O11014− or AgP5W30O11014−) and ribosome-targeting antibiotics for high antibacterial efficiency with low risk of antibiotic resistance. Due to their ultra-small sizes and active surface ligands, POM anions show strong affinity to bacterial cell membrane and impose hyperpolarization of the bacterial cells as well as the decrease of Mg2+ influx by blocking Mg2+ transporters, which finally lead to the structural perturbations of ribosomes and instability of bacterial structures. The bacterial growth can, therefore, be regulated by the presence of POMs: a fraction of Bacillus subtilis shifted to a ‘dormant’, slow-growing cellular state (an extended lag phase) upon the application of subinhibitory concentration of POMs. An approach to combat antibiotic resistant bacteria by applying POMs at their early growth phase followed by antibiotic exposure is validated, and its high efficiency for bacterial control is confirmed.
Preyssler-type polyoxometalates (POMs) were demonstrated the ability to modulate cell growth rate via the hyperpolarization of bacterial cells and the so-resulted blocking of the Mg2+ flux into bacterial cells. The synergy of the combination of POMs and ribosomes-targeting antibiotics benefits high antibacterial efficiency with low risk of antibiotic resistance. Display omitted
•Preyssler-type polyoxometalates (POMs) modulate bacterial cellular hyperpolarization.•Preyssler-type POMs induce a lag phase in bacterial growth.•Selective pressure of ribosome-targeting antibiotic is reduced by co-applying POMs.•The request doses in bacterial control are significantly lowered.
Sub-nm-scale metal oxide clusters (PW
12
O
40
3−
) show high solubility in the melt of poly(ethylene glycol) (PEG) and the obtained semi-solid nanocomposites show promising proton conductivities ...under ambient conditions. Suggested from scattering studies, the clusters are homogeneously dispersed in the PEG melt at the molecular scale with high loading amounts (70 wt%) and the formed real solutions can be stable for months with no aggregation or phase separation. The conductivities of the nanocomposites which are governed by the concentrations of H
3
PW
12
O
40
can reach as high as 1.01 × 10
−2
S cm
−1
at the highest concentration. Due to the dynamic cross-linking hydrogen bonding between clusters and PEG, the nanocomposites behave like solids with negligible flow at high concentrations of clusters. Upon the application of high-speed shear forces (>32 s
−1
), the composites can flow with continuously decreasing viscosities. The shear thinning properties of the nanocomposites enable their convenient processing into required morphologies and the wettability of electrolytes to electrodes under typical high shear rate processing conditions and the safety of the produced devices can be ensured by their solid-like properties in the static state.
PEG-POM nanocomposites are ideal candidates for semi-solid proton conductors with high proton conductivities and devisable mechanical performances.
The assembly of two achiral POMs of Lindqvist and Anderson through strong covalent linkages, using bifunctional TRIS with a rotatable C−N single bond, gives two nanoscale rod-like chiral molecular ...triads with C 2 symmetry, the chirality of which were confirmed by the single crystal X-ray diffraction analyses and solid CD spectroscopy measurements. The enantiopure crystals of these compounds have been obtained by spontaneous resolution upon crystallization in the absence of any chiral source. The present work opens a way to make chiral nanostructures from achiral polyoxoanions, which may have potential applications in asymmetric catalysis, NLO, and ferroelectric materials.
Long-lasting protective immune responses are expected following vaccination. However, most vaccines alone are inability to evoke an efficient protection. The combinatory administration of adjuvants ...with vaccines is critical for generating the enhanced immune responses. Herein, with biocompatible poly(4-vinylpyridine) (P4VP) as template, 2.5 nm iron/molybdenum oxide cluster, {Mo
72
Fe
30
}, is applied as an adjuvant to co-assemble with antigens of
Mycobacterium bovis
via hydrogen bonding at molecular scale. Molecular scale integration of the antigens and {Mo
72
Fe
30
} and their full exposure to body fluid media contribute to the augmentation of both humoral and cellular immune responses of the vaccines after inoculation in mice. Anti-inflammatory factor IL-10 gradually increases after 2 weeks followed by a final back to normal level by the 5th week. The balance between proinflammatory cytokines and anti-inflammatory factors suggests that immune system can be activated in the early stage of infection by the antigens carried by the supra-particles and secrete acute inflammatory factors for host defense and antiinflammatory factors for immune protection.
Olefin/paraffin separation is an important but challenging and energy-intensive process in petrochemical industry. The realization of carbons with size-exclusion capability is highly desirable but ...rarely reported. Herein, we report polydopamine-derived carbons (PDA-Cx, where x refers to the pyrolysis temperature) with tailorable sub-5 Å micropore orifices together with larger microvoids by one-step pyrolysis. The sub-5 Å micropore orifices centered at 4.1-4.3 Å in PDA-C800 and 3.7-4.0 Å in PDA-C900 allow the entry of olefins while entirely excluding their paraffin counterparts, performing a precise cut-off to discriminate olefin/paraffin with sub-angstrom discrepancy. The larger voids enable high C
H
and C
H
capacities of 2.25 and 1.98 mmol g
under ambient conditions, respectively. Breakthrough experiments confirm that a one-step adsorption-desorption process can obtain high-purity olefins. Inelastic neutron scattering further reveals the host-guest interaction of adsorbed C
H
and C
H
molecules in PDA-Cx. This study opens an avenue to exploit the sub-5 Å micropores in carbon and their desirable size-exclusion effect.
We present a brief overview of current investigations on the dynamics of supramolecular assemblies, with the focus on applying broadband dielectric spectroscopy (BDS) combined with different ...techniques. The dielectric methods have significant advantages in probing the dynamical signature and scaling of supra-structures. We summarize various mechanisms describing supramolecular dynamics, which could produce a relaxation governed by supramolecular association slower than the glass-transition-related structural relaxation. Then, we also discuss the relaxation dynamics in supramolecular assembly under nanoconfinement, for controlling bonus macroscopic performances. This perspective emphasizes the idea that the relaxational response of supramolecular assemblies is generic to some extent. It does not necessarily depend on the chemistry of associations, but could reflect supra-materials’ behaviors determined by their molecular architectures.
Intermittent outbreaks of global pandemic disease have spurred new sensors and medicines development for the prevention of disease spread. This perspective specifically covers recent advances, ...challenges, and future directions in virus-mimetic polymeric nanostructures and their application in biological medicines with a special emphasis on subunit vaccine development. With tailorable compositions and properties, polymers facilitate the ingenious design of various polymeric nanostructures. As one type of polymeric nanostructures, virus-mimetic polymeric nanostructures have been developed as an attractive platform for enhanced immune responses, since they combine the merits of polymer nanocores with the biomimetic characteristic of virus which displays multivalent epitopes on their surfaces. This perspective also provides an applicative approach to rationally design virus-mimetic polymeric platforms based on nanostructures that are self-assembled by using polymers as templates and the antigens and metal oxide clusters loaded on their surface to mimic viruses in size and surface antigenicity. Sub-200 nm virus-mimetic polymeric nanostructures are in a relatively lower level of endotoxins and can promote the antigens to elicit potent humoral and cellular immune responses against pathogenic bacteria. The promising development of virus-mimetic polymeric nanostructures will continue to protect human health from common pathogens and emerging infectious threats.
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