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Colloidal liquid crystals account for various applications due to the combination of characteristics relevant for liquid crystals and colloids. The authors elaborate the impact of concave geometry on the properties of colloidal liquid crystals for development of functional materials.

Abstract Nanoparticle (NP)‐based vehicles are attractive for biomedical delivery and therapy, owing to improved therapeutic efficiency and reduced adverse effects compared to free drugs. Uncontrolled NP heterogeneity at the suspension level or single particle level poses grand challenges in the effective use of NPs for biology and medicines. Precision nanoparticles (PNPs) are a class of discrete nanostructures exhibiting elaborately tailored surface or structural heterogeneity, but minimal variations between nanostructures in one solution. Benefiting from their precisely controlled NP heterogeneity, PNPs have emerged as promising platforms for modulating various biological processes to improve the biomedical performance of NP‐based vehicles. This review summarizes recent advances in the development of precisely tailored PNPs for biomedical applications, with an emphasis on the nano‐bio interactions, and drug delivery and therapy. We start with a brief overview of the major categories of PNPs and their fabrication strategies (section 2). We then focus on reviewing the use of PNPs for enhancing biomolecular recognition or detection, regulating the NP‐protein interactions, modulating the NP‐biomembrane interactions, and improving the biological delivery and therapy (section 3). Finally, we discuss the challenges and perspectives on the design and use of PNPs for biomedical applications (section 4).

Abstract How to fabricate scale low-cost microfluidic device for detection of biomarkers owns a great requirement. Herein, it is for the first time reported that a new microfluidic device based on bonding polydimethylsiloxane microfluidic channels onto the substrate of a screen-printed electrode with coating glass solution was fabricated for electrochemical sensing of prostate-specific antigen (PSA). Compared to traditional microfabrication processes, this method is simple, fast, low cost, and also suitable for mass production. The prepared screen-printed electrode-based microfluidic device (CASPE-MFD) was used for the detection of the PSA in human serum. The prepared CASPE-MFD had a detection limit of 0.84 pg/mL (25.8 fM) and a good linearity with PSA concentration ranging from 0.001 to 10 ng/mL, which showed a great promise platform toward the development of miniaturized, low-cost electrochemical microfluidic device for use in human health, environmental monitoring, and other applications.

Abstract Melamine, which induces proximal tubular (PT) cell damage has a greater nephrotoxic effect when combined with cyanuric and uric acids; however, it is unknown whether such effect can stimulate calcium phosphate (CaP)/calcium oxalate (CaOx) stone formation. Here, we show that melamine acts as an inducer of CaP, CaOx and CaP + CaOx (mixed) crystal formations in a time and concentration-dependent manner by stabilizing those crystals and further co-aggregating with melamine. To explore the physiological relevance of such melamine-augmented calcium crystal formation, we used 2-dimensional (2D) and 3D microfluidic (MF) device, embedded with PT cells, which also resembled the effect of melamine-stimulated CaP, CaOx and mixed crystal formation. Significantly, addition of preformed CaP and/or CaOx crystal in the presence of melamine, further potentiated those crystal formations in 3D MFs, which helped the growth and aggregation of mixed crystals. Our data show that the mechanism of such predisposition of stone formation could be largely due to co-crystallization between melamine and CaP/CaOx and pronounced effect on induction of stone-forming pathway activation in 3D MF. Taken together, melamine-induced CaP and/or CaOx crystal formation ex-vivo will help us in understanding the larger role of melamine as an environmental toxicant in producing the pathology in similar cellular microenvironments.

Solution-phase welding of nanoparticles to form larger structures typically requires that the particles are the same type, limiting the diversity of possible products. Here, the authors report a welding process between gold and chalcogenide nanoparticles in dispersion that leads to asymmetric hybrid nanoparticles with two distinct domains.

Monodisperse biaxial colloidal particles are used as model systems to understand the phase behavior of biaxial molecules but high-quality biaxial colloids are limited. Here the authors describe gram-scale synthesis of uniform biaxial colloidal cuboids and their assembly into mesophasic structures.

Plasmonic metal nanoparticles have unique optical properties, such as localized surface plasmon resonance resulting from the oscillation of free electrons. Integrating discrete plasmonic nanoparticle into assembled nanostructures enables interparticle plasmon coupling and collective properties that are often absent in their discrete counterparts. Synthetic polymers as surface ligands on plasmonic nanoparticles can stabilize the nanoparticles, define the surface properties, control the interparticle interactions and therefore direct the nanoparticle self-assembly. Given the length scale of polymers comparable to the size of plasmonic nanoparticles of interest, polymer ligands are promising for precisely controlling the interparticle interaction. Engineering polymer ligands in the terms of their chemical composition, grafting density, anchoring groups and chain lengths is critical to control the assembly nanostructures and plasmon coupling of adjacent nanoparticles. The focus of this perspective is to identify and address the unmet challenges in the field of polymer-grafted plasmonic nanoparticles (PGNPs). Key unresolved issues broadly covered from the design of PGNP building blocks to their self-assembly are illustrated by highlighting a few examples. In views of more robust building blocks, the choice of inexpensive metals, the new anchoring groups and precision control of polymer ligands are discussed. We further consider the challenges in breaking the surface symmetry of plasmonic nanoparticles and designing synthetic polymers to achieve reversibility and directionality in the self-assembly of PGNPs.

Self-assembly of giant building blocks beyond conventional molecules offers tremendous opportunities for the fabrication of new-generation structural materials. This work describes the macroscopic colloidal segregation in the vesicular self-assembly of binary nanoparticle amphiphiles (NPAMs) consisting of block copolymer-grafted nanoparticles in solution. Depending on their relative size and concentration, binary NPAMs with distinctive sizes assemble into hybrid vesicles with different morphologies, namely, homogeneous vesicles, patchy vesicles, and yolk/shell vesicles. The segregation of NPAMs confined within or escaped from the vesicular membrane is driven by the conformational entropy gain of end-grafted copolymer ligands. The effect of NPAM size and concentration on the morphological transition of vesicles is mapped in a phase diagram. Moreover, a vesicular fusion/budding mechanism is proposed to illustrate the formation of uniform vesicles with yolks inside. The hybrid vesicles have potential applications in cancer imaging, biosensing, and drug delivery.

Multicomponent colloidal nanostructures have topologically dependent chemical and physical properties, but are difficult to synthesise with high order complexity. Here, Nie and co-workers show a general and scalable route to synthesise such structures with unique coaxial-like construction.

Conductive asphalt concrete has excellent self-monitoring abilities for internal damage and attractive application prospects. By studying the resistance and strain changes under indirect tensile deformation, three distinct stages of output resistivity changes are observed during the destruction of the specimen. In the initial loading stages, contact between the mixture particles tightens because the specimen under loading forms a more conductive path, and the resistivity decreases significantly. In the second stage, asphalt concrete deforms smoothly; small changes in the interior of the asphalt concrete also correspond to small changes in resistivity. In the final stage, because of the progressive development of cracks in asphalt concrete, the specimens are destroyed, and the conductive paths are also seriously damaged, significantly increasing resistivity. This change in the resistivity value exceeds 50%. Conductive asphalt concrete also has a good self-monitoring ability regarding the strain caused by the applied stress. The unit strain corresponding to changes in resistivity is greater when graphite content is lower. CT (Computer Tomography)identification can confirm that changes in resistivity are caused by material changes in the interior due to fatigue failure. The decrease or increase in resistivity is the result of a decrease or increase in the internal porosity of the material.

A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed) and plastic permanent strain (PPS) of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC) and three degrees of compaction (90%, 93%, and 96%). Then the specimens were dried or wetted to different moisture contents (OMC, OMC±3%, OMC±6%, and OMC+9%) prior to testing for Ed and PPS. Results show that moisture content has greater influence on the Ed and PSS than compaction degree, and the increase in moisture content leads to a decrease of Ed and an increase of PPS. Furthermore, an empirical relationship between Ed and applied cyclic stress (σd) is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc) separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves of σdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.

A microfluidic approach is described for generating capsules of biopolymer hydrogels at room temperature and with good control of particle size distribution and internal structure. The time of gelation and/or the concentration of the cross-linking agent in the continuous phase are controlled in order to achieve control over the internal structure of biomicrogels from capsules to gradient microgels to microgels with a uniform structure.

The internal trigger approach is applied for multistep microfluidic polymerization reactions conducted in droplets, namely, polyaddition and polycondensation. The microfluidic synthesis has helped in conducting efficient screening of the compositions of the monomer mixtures and for producing polymer particles with a narrow size distribution and a predetermined size.

A predefined self-organization of gold nanorods (NRs) end-terminated with multiple polymer arms ('pom-poms') is described in higher-order structures. The superposition of the two variables controlling the organization of NR has helped in creating a map showing the variation in the longitudinal plasmonic bands of the NRs achieved by their self-assembly.

Fast continuous synthesis of Janus particles (JPs) and three-phase particles with narrow size distribution or ternary particles is effected by a microfluidic method, which includes emulsification of monomer liquids and in-situ photoinitiated polymerization of multiphase droplets. The strategy for precise control over the structure of JPs and their structure-dependent assembly in clusters is presented, demonstrating an asymmetric chemical modification of the surface of JPs by conjugating them with protein molecules.

An approach for the continuous and scalable production of core-shell droplets and polymer capsules in microfluidic devices is reported. Polymer particles of various shapes and morphologies were obtained by photopolymerization of the monomeric shells.

The present study aimed to investigate the association between endothelial progenitor cells (EPCs) and peptic ulcers in patients with or without type 2 diabetes mellitus (T2DM), in association with the efficiency of peptic ulcer treatment. The study recruited healthy subjects and peptic ulcer patients with or without T2DM. All the ulcer patients, including those with and without T2DM, were administered omeprazole for 8 weeks. Peptic ulcer patients with T2DM were additionally treated with glipizide and novolin. Blood samples were then obtained from the three groups following ulcer treatment. CD133+ cells were isolated from the blood samples using magnetic bead selection, and cultured in complete medium 199. Morphological and quantity changes in EPCs were observed by light and fluorescence microscopy. In addition, flow cytometric analysis was used to quantify the number of vascular endothelial cells. The treatment was partially effective in 7 of the 32 peptic ulcer patients without T2DM and 12 of the 32 peptic ulcer patients with T2DM. However, this treatment was ineffective in 20 of the 32 peptic ulcer patients with T2DM. Notably, 25 peptic ulcer patients without T2DM were defined as completely recovered following treatment. In addition, the number of circulating EPCs as well as their colony forming ability was significantly reduced (P<0.05) in the peptic ulcer patients with T2DM following ulcer treatment, compared with the other groups. Circulating EPC counts were significantly increased in peptic ulcer patients without T2DM, as compared with the healthy controls. With regards to colony formation, peptic ulcer patients without T2DM did not exhibit improved colony formation ability. In conclusion, the number of circulating EPCs and their colony-forming ability was significantly reduced in peptic ulcer patients with T2DM following ulcer treatment when compared with the other groups. This suggests that the poor curative effect of peptic ulcer treatment in these patients is associated with impairment of EPCs. [ABSTRACT FROM AUTHOR]

A hybrid nanocomposite comprising 5CB liquid crystal (LC) and block copolymer (BCP) functionalized barium titanate ferroelectric nanoparticles was prepared. This hybrid system exhibits a giant soft-memory effect that was detected by dielectric hysteresis. Spontaneous polarization of ferroelectric nanoparticles couples synergistically with the radially aligned BCP chains to create nanoscopic domains where LC mesogens can align directionally. Such domains can be rotated electromechanically and locked in space even after the removal of the applied electric field. The resulting non-volatile memory is several times larger than the non-functionalized sample and provides an insight into the role of non-covalent polymer functionalization on enhancing the size of the nanoscopic domains. [ABSTRACT FROM AUTHOR]

Nature offers a plethora of astonishing examples of shapes and functions from the aspects of both simplicity and complexity. The creation of synthetic systems that can morph in a controlled manner as seen in nature is of paramount importance in many fields of fundamental and applied sciences. The tremendous interest in self-shaping materials stems from a wide range of applications for these materials, ranging from biomedical devices to aircraft design. This review article highlights recent advances in understanding and designing thin, sheet-like soft materials that can transform into complex three-dimensional structures in a controlled manner by modulating the internal stresses. We review the general principles underlying shape transformation phenomena in natural and synthetic systems, and the significant achievements in fabricating self-shaping of soft materials via representative examples. We conclude with a discussion on the challenges facing the field, and future directions from the perspective of theoretical and experimental methodology and interdisciplinary applications. [ABSTRACT FROM AUTHOR]

We report a microfluidic (MF) approach to studies of temperature mediated carbon dioxide (CO2) transfer between the gas and the liquid phases. Micrometre-diameter CO2bubbles with a narrow size distribution were generated in an aqueous or organic liquid and subsequently were subjected to temperature changes in the downstream channel. In response to the cooling-heating-cooling cycle the bubbles underwent corresponding contraction-expansion-contraction transitions, which we term ‘bubble breathing’. We examined temperature-controlled dissolution of CO2in four exemplary liquid systems: deionized water, a 0.7 M aqueous solution of NaCl, ocean water extracted from Bermuda coastal waters, and dimethyl ether of poly(ethylene glycol), a solvent used in industry for absorption of CO2. The MF approach can be extended to studies of other gases with a distinct, temperature-dependent solubility in liquids. [ABSTRACT FROM AUTHOR]

The combination of simple Electrochemical Micro-Paper-based Analytical Devices (EµPADs) with commercially available glucometers allows rapid, quantitative electrochemical analysis of a number of compounds relevant to human health (e.g., glucose, cholesterol, lactate, and alcohol) in blood or urine. [ABSTRACT FROM AUTHOR]

This paper describes three-dimensional microfluidic paper-based analytical devices (3-D µPADs) that can be programmed (postfabrication) by the user to generate multiple patterns of flow through them. These devices are programmed by pressing single-use ‘on’ buttons, using a stylus or a ballpoint pen. Pressing a button closes a small space (gap) between two vertically aligned microfluidic channels, and allows fluids to wick from one channel to the other. These devices are simple to fabricate, and are made entirely out of paper and double-sided adhesive tape. Programmable devices expand the capabilities of µPADs and provide a simple method for controlling the movement of fluids in paper-based channels. They are the conceptual equivalent of field-programmable gate arrays (FPGAs) widely used in electronics. [ABSTRACT FROM AUTHOR]

Self-organization of nanoparticles is an efficient strategy for producing nanostructures with complex, hierarchical architectures. The past decade has witnessed great progress in nanoparticle self-assembly, yet the quantitative prediction of the architecture of nanoparticle ensembles and of the kinetics of their formation remains a challenge. We report on the marked similarity between the self-assembly of metal nanoparticles and reaction-controlled step-growth polymerization. The nanoparticles act as multifunctional monomer units, which form reversible, noncovalent bonds at specific bond angles and organize themselves into a colloidal polymer. We show that the kinetics and statistics of step-growth polymerization enable a quantitative prediction of the architecture of linear, branched, and cyclic self-assembled nanostructures; their aggregation numbers and size distribution; and the formation of structural isomers. [ABSTRACT FROM AUTHOR]