Tailoring 3D shapes of polyhedral milliparticles by adjusting orthogonal projection in a microfluidic channel

Polyhedral milliparticles (PMPs) have promising applications in self-assembly, tissue engineering, mechanical engineering, and photonics. The shapes and sizes of the PMPs have great impact on their functions. To date, the reported methods for adjusting the shapes and sizes of PMPs are still limited. Especially, it remains a challenge to fabricate the PMPs with high asymmetry. Here, we present a facile and efficient approach that focuses on the alteration of the relative positions between the microchannel and the UV light to tailor the shaping process of the PMPs. By tuning the rotation angle and translation displacement, a variety of monodisperse PMPs with both centrosymmetric and noncentrosymmetrical structures are synthesized, including tetrahedra, pentahedra, hexahedra, and so forth. Moreover, the polymeric PMPs are loaded with silica nanoparticles and further sintered into silica. The obtained silica PMPs hold great potential for the applications such as machining tools, abrasives, and electronics.     

Dissection the endocytic routes of viral capsid proteins-coated upconversion nanoparticles by single-particle tracking

Real-time exploring the cellular endocytic pathway of viral capsid proteins (VCPs) functionalized nanocargos at the single-particle level can provide deep insight into the kinetic information involved in virus infection. In this work, porcine circovirus type 2 (PCV2) VCPs with different functions are modified onto the surface of upconversion nanoparticles (VCPs-UCNPs) to investigate the cellular internalization process in real-time. Clathrin-mediated endocytosis is found to be the essential uptake mechanism for these VCPs-UCNPs. Besides, it is verified that P₁-UCNPs (PCV2 VCPs with nuclear localization signal, namely P₁) can be easily assembled close to the perinuclear area, which is different from that of P₂-UCNPs (PCV2 VCPs without nuclear localization signal, namely P₂). Interestingly, multistep entry processes are observed. Particularly, confined diffusion is observed during the transmembrane process. The intracellular transport of VCPs-UCNPs is dependent on microtubules toward the cell interior. During this process, P₁-UCNPs display increased velocities with active transport, while diffusion much faster around the perinuclear area. But for P₂-UCNPs, there are only two phases involved in their endocytosis process. This study presents distinct dynamic mechanisms for the nanocargos with different functions, which would make a useful contribution to the development of robust drug delivery systems.     

Directed Nanoparticle Assembly through Polymer Crystallization

Nanoparticles can be assembled into complex structures and architectures by using a variety of methods. In this review, we discuss recent progress of using polymer crystallization (particularly polymer single crystals, PSCs) to direct nanoparticle assembly. PSCs have been extensively studied since 1957. Mainly appearing as quasi-two-dimensional (2D) lamellae, PSCs are typically used as model systems to determine polymer crystalline structures, or as markers to investigate the crystallization process. Recent research has demonstrated that they can also be used as nanoscale functional materials. Herein, we show that nanoparticles can be directed to assemble into complex shapes by using in situ or ex situ polymer crystal growth. End-functionalized polymers can crystallize into 2D nanosheet PSCs, which are used to conjugate with complementary nanoparticles, leading to a nanosandwich structure. These nanosandwiches can find interesting applications for catalysis, surface-enhanced Raman spectroscopy, and nanomotors. Dissolution of the nanosandwich leads to the formation of Janus nanoparticles, providing a unique method for asymmetric nanoparticle synthesis.     

General one-pot strategy to prepare multifunctional nanocomposites with hydrophilic colloidal nanoparticles core/mesoporous silica shell structure

A general and facile strategy was developed to coat hydrophilic inorganic nanoparticles directly with mesoporous silica nanoparticles (MSNs). The cationic surfactant of cetyltrimethylammonium bromide (CTAB) was adsorbed to various negatively charged CdTe quantum dots, Fe(3)O(4) nanocrystals or Au nanoparticles, introducing the bilayer of CTAB overcoating with positive charge. The subsequent sol-gel reaction of TEOS with the basic catalyst resulted in uniform nanocomposites. The concentration of CTAB and NH(4)OH in the recipe strongly influenced the number of inorganic nanoparticles in the nanocomposites and the homogeneity of MSNs shell. One dimensional Au nanorods and larger size of solid SiO(2) nanoparticles were also able to coat with MSNs using a similar synthetic procedure. The proposed method was greatly simplified without the help of any mediators or silane coupling agents and excellent mesostructural performance was readily achieved. Compared to the methods known from the literatures for the coating of hydrophobic nanoparticles, this efficient way is especially useful for trapping different hydrophilic nanoparticles with arbitrary sizes and shapes into MSNs. These highly versatile multifunctional nanocomposites, together with the pH-responsible drug release behaviors, non-toxicity to normal cells and ease of uptake into cancer cells, are expected to be utilized as drug delivery system for simultaneous imaging and therapeutic applications.     

Methods of virus formation

Viruses occur in a great variety of shapes and sizes, but for all their diversity in appearance they possess certain characteristics in common: all viruses contain a single nucleic acid molecule – deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) – surrounded by a protective protein coat. Among other things, the protein coat enables the genetic information stored in the nucleic acid to enter a host cell in a usable state, where it can initiate the reproduction of identical virus particles. After penetration of the cell the foreign genetic material of the virus particle first induces the synthesis of macromolecules not normally present in the cell: the viral nucleic acid undergoes replication and very many copies are produced, the protein of the virus coat is synthesized, and then these components are assembled to form a new generation of infectious virus particles. Most viruses also exhibit certain common structural features: their protein coat is built up from subunits arranged in helical or icosahedral fashion around the genetic material.     

由嵌段共聚物制备有形状的核壳结构聚合物纳米颗粒

嵌段共聚物可自发组装形成形貌丰富的纳米粒子和有序纳米结构的材料,为纳米材料和纳米技术领域提供了很重要的新材料和新手段.该领域的进一步发展提出了对嵌段共聚物的自组装体赋予功能性的要求,即需要通过可控聚合反应合成反应性嵌段共聚物,并且对其自组装的纳米粒子进行结构、形状及功能性的调控.本文针对以上研究目标,结合本课题组在该领...     

Nanoparticles and cells: good companions and doomed partnerships

Engineered nanoparticles are emerging as useful tools for different purposes in life sciences, medicine and agriculture. Nanomedicine, an emerging discipline, involves the application of nanotechnology (usually regarded within the size range of 1-1000 nm) in the design of systems and devices that can facilitate our understanding of disease pathophysiology, nano-imaging, nanomedicines and nano-diagnostics. Among the different nanomaterials used to construct nanoparticles, are organic polymers, co-polymers and metals. Some of these materials can self assemble, and depending on the conditions under which the self-assembly process occurs, a vast array of shapes can be formed. Frequently, the nanoparticle morphology is spherical or tubular, mimicking the shape, but thus far, not the functions of subcellular organelles. We discuss here several representative nanoparticles, made of block copolymers and metals, highlighting some of their current uses, advantages and limitations in medicine. Nano-oncology and nano-neurosciences will also be discussed in more detail in the context of the intracellular fate of nanoparticles and possible long-term consequences on cell functions.     

Template-Free Self-Assembly of Artificial De Novo Viral Coat Proteins into Nanorods: Effects of Sequence,Concentration, and Temperature

The self-assembly of protein polymers is a promising route to prepare sophisticated functional nanostructures. However, the interplay between protein self-assembly by itself and its co-assembly with a template is not well understood. Silk-based protein polymers that co-assemble with DNA to form rod-like artificial viruses are herein developed and the effects of silk block length, concentration, and temperature in the self-assembly of the proteins alone are characterized by using a combination of bulk dynamic light scattering (DLS) and single-molecule atomic force microscopy (AFM). Protein nanorods were slowly formed (up to hours) through the interaction of the silk-like blocks. The proteins present a silk-length dependent critical elongation concentration, and above it the amount and size of nanorods rapidly increase. Temperature-dependent light scattering data was adequately fitted into a cooperative model of nucleation–elongation. These results are also important to understand the self-assembly of designed viral coat proteins with DNA templates to form artificial virus-like particles and help us to define general guidelines to design proteins with the ability to precisely organize matter at the nanoscale.     

A general method for the synthesis of nanostructured large-surface-area materials through the self-assembly of functionalized nanoparticles

A general synthetic method for the preparation of nanostructured materials with large surface area was developed by using nanoparticle building blocks. The preparation route involves the self-assembly of functionalized nanoparticles in a liquid-crystal phase. These nanoparticles are functionalized by using difunctional amino acid species to provide suitable interactions with the template. Optimum interactions for self-assembly of the nanoparticles in the liquid-crystal phase were achieved with one -NH2 group anchored to the nanoparticle surface per 25 A(2). To maximize the surface area of these materials, the wall thicknesses are adjusted so that they are composed of a monolayer of nanoparticles. To form such materials, numerous parameters have to be controlled such as the relative volume fraction of the nanoparticles and the template and size matching between the hydrophilic component of the copolymer and nanoparticles. The surface functionalization renders our synthetic route independent of the nanoparticles and allows us to prepare a variety of nanostructured composite materials that consist of a juxtaposition of different discrete oxide nanoparticles. Examples of such materials include CeO2, ZrO2, and CeO2-Al(OH)3 composites.     

Biomolecular interactions with nanoparticles: applications for coronavirus disease 2019

Nanoparticles are small particles sized 1–100 nm, which have a large surface-to-volume ratio, allowing efficient adsorption of drugs, proteins, and other chemical compounds. Consequently, functionalized nanoparticles have potential diagnostic and therapeutic applications. A variety of nanoparticles have been studied, including those constructed from inorganic materials, biopolymers, and lipids. In this review, we focus on recent work targeting the severe acute respiratory syndrome coronavirus 2 virus that causes coronavirus disease (COVID-19). Understanding the interactions between coronavirus-specific proteins (such as the spike protein and its host cell receptor angiotensin-converting enzyme 2) with different nanoparticles paves the way to the development of new therapeutics and diagnostics that are urgently needed for the fight against COVID-19, and indeed for related future viral threats that may emerge.     

Synthesis and self-assembly of highly monodispersed quasispherical gold nanoparticles

We report the synthesis of cetyltrimethylammonium bromide (CTAB) assisted seed mediated growth of highly pure and monodispersed quasispherical gold nanoparticles (QAuNPs) and their self-assembly on the silica/glass substrates. The seed-mediated growth approach was modified to prepare size-tunable monodispersed QAuNPs with sizes ranging from 20 to 150 nm. The larger, more uniform seeds and lower CTAB concentration resulted in the formation of relatively large QAuNPs with improved monodispersity (relative standard deviation (RSD) of ～5-8%) and high purity in their shapes. In addition, CATB-capped QAuNPs can be spontaneously assembled into closely packed and highly aligned superstructures with well-defined mutillayers (two to six layers) on silica substrates. Furthermore, CATB-capped QAuNPs can easily construct density-controllable QAuNP chips by electrostatic self-assembly, showing their promising applications for single-nanoparticle plasmonic sensors.     

Recent progress in the synthesis of inorganic nanoparticles

Nanoparticles probably constitute the largest class of nanomaterials. Nanoparticles of several inorganic materials have been prepared by employing a variety of synthetic strategies. Besides synthesizing nanoparticles, there has been considerable effort to selectively prepare nanoparticles of different shapes. In view of the great interest in inorganic nanoparticles evinced in the last few years, we have prepared this perspective on the present status of the synthesis of inorganic nanoparticles. This article includes a brief discussion of methods followed by reports on the synthesis of nanoparticles of various classes of inorganic materials such as metals, alloys, oxides chalcogenides and pnictides. A brief section on core-shell nanoparticles is also included.     

Self-assembly of “patchy” nanoparticles: a versatile approach to functional hierarchical materials

The solution-phase self-assembly or “polymerization” of discrete colloidal building blocks, such as “patchy” nanoparticles and multicompartment micelles, is attracting growing attention with respect to the creation of complex hierarchical materials. This approach represents a versatile method with which to transfer functionality at the molecular level to the nano- and microscale, and is often accompanied by the emergence of new material properties. In this perspective we highlight selected recent examples of the self-assembly of anisotropic nanoparticles which exploit directional interactions introduced through their shape or surface chemistry to afford a variety of hierarchical materials. We focus in particular on the solution self-assembly of block copolymers as a means to prepare multicompartment or “patchy” micelles. Due to their potential for synthetic modification, these constructs represent highly tuneable building blocks for the fabrication of a wide variety of functional assemblies.     

基于贻贝仿生化学的分离功能材料

贻贝仿生的表面化学是近年来材料学、化学、生物医学等领域的交叉研究热点。多巴胺可以作为贻贝足丝蛋白(Mfp)超强黏附特性的模型分子,通过复杂的氧化-自聚和组装,形成多种功能的聚多巴胺(PDA)纳米涂层和纳米粒子,在分离膜、吸附材料、生物医用材料、生物黏结剂等领域有着广阔的应用前景。本研究小组近年来持续开展了基于贻贝仿生化学的分离功能材料制备与结构调控的研究工作,率先将多巴胺表面沉积方法应用于多孔分离膜表面的构建与功能化,提出了多巴胺的自聚-沉积过程模型,进而验证了PDA沉积层的纳滤分离特性,建立了一条简单方便的膜表面功能化与纳滤膜制备新途径。本文主要对基于贻贝仿生化学的分离功能材料,特别是分离膜的研究进展进行综述,并对将来的发展趋势进行展望。     

Self-assembled gelators for organic electronics

Nature excels at engineering materials by using the principles of chemical synthesis and molecular self-assembly with the help of noncovalent forces. Learning from these phenomena, scientists have been able to create a variety of self-assembled artificial materials of different size, shapes, and properties for wide ranging applications. An area of great interest in this regard is solvent-assisted gel formation with functional organic molecules, thus leading to one-dimensional fibers. Such fibers have improved electronic properties and are potential soft materials for organic electronic devices, particularly in bulk heterojunction solar cells. Described herein is how molecular self-assembly, which was originally proposed as a simple laboratory curiosity, has helped the evolution of a variety of soft functional materials useful for advanced electronic devices such as organic field-effect transistors and organic solar cells. Highlights on some of the recent developments are discussed.     

Self-Assembling Organic Nanotubes

Hollow tubular structures of molecular dimensions perform diverse biological functions in nature. Examples include scaffolding and packaging roles played by cytoskeletal microtubules and viral coat proteins, respectively, as well as the chemical transport and screening activities of membrane channels. In the preparation of such tubular assemblies, biological systems make extensive use of self-assembling and self-organizing strategies. Owing to numerous potential applications in areas such as chemistry, biology, and materials science considerable effort has recently been devoted to preparation of artificial nanotubular structures. This article reviews design principles and the preparation of synthetic organic nanotubes, with special emphasis on noncovalent processes such as self-assembly and self-organization.     

基于生物大分子的纳米药物载体

生物大分子材料由于其可再生性、无毒性以及良好的生物相容性、生物可降解性和黏膜粘附性等特点成为药物载体研究的热点,尤其是将其作为纳米药物载体材料更加受人关注。本文首先对生物大分子纳米颗粒常用的制备方法--乳化法、自组装法和离子凝聚法进行了详细的介绍。由于乳化法在一定程度上破坏了生物大分子的生物相容性,因此自组装法和离子凝聚法是比较理想的制备方法。其中自组装法是利用两亲性的生物大分子,如蛋白质、多糖衍生物等在静电作用、疏水作用、范德华力等非键合作用力下组装成纳米结构;而离子凝聚法则是利用聚电解质与带相反电荷物质之间的静电作用形成纳米结构。接着本文对通过这些方法获得的生物大分子纳米颗粒作为蛋白类药物、抗癌药物以及基因药物的载体在近年来的研究进展进行了归纳和总结,结果显示其在药物缓释体系中具有广阔的应用前景。     

Green formulation,chemical characterization and anti-acute leukemia effects of vanadium nanoparticles containing Foeniculum vulgare extract

In this study, vanadium nanoparticles (VNPs) were green synthesized using Foeniculum vulgare extract. VNPs were characterized using chemical analysis techniques including FT-IR, XRD, FE-SEM, TEM and EDS. The microscopy techniques revealed a spherical morphology for the particles with size less than 50 nm. According to XRD data V₂O₅ was confirmed for VNPs. Maybe significant anti-human acute leukemia potentials of the synthesized nanoparticles against common human acute leukemia cell lines are linked to their antioxidant activities. MTT assay was used on common acute leukemia cell lines i.e., 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 to survey the cytotoxicity and anti-acute leukemia effects of the synthesized nanoparticles. The synthesized nanoparticles had very low cell viability and high anti-acute leukemia activities dose-dependently against 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 cell lines without cytotoxicity on the normal cell line (HUVEC). To determine the antioxidant properties of the synthesized nanoparticles, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. The IC₅₀ of VNPs were 25, 33 and 26 µg/mL against 32D-FLT3-ITD, MOLT-3 and Jurkat, Clone E6-1 cell lines, respectively. The synthesized nanoparticles inhibited half of the DPPH molecules in the concentration of 28 µg/mL.     

Electric field-induced self-assembly of micro- and nanoparticles of various shapes at two-fluid interfaces

Particle lithography which explores the capability of particles to self-assemble offers an attractive means to manufacture nanostructured materials. Although traditional techniques typically lead to the formation of dense crystals, adjustable non-close-packed crystals are crucial in a number of applications. We have recently proposed a novel method to assemble spherical micro- and nanoparticles into monolayers. The technique consists of trapping particles at a liquid-fluid interface and applying an electric field normal to the interface. Particles rearrange themselves under the influence of interfacial and electrostatic forces to form 2-D hexagonal arrays of long-range order and whose lattice constant depends on the electric field strength and frequency. Furthermore, the existence of an electric field-induced capillary force makes the technique applicable to submicron and nanosized particles. Although spherical particles are often used, non-spherical particles can be beneficial in practice. Here, we review the method, discuss its applicability to particles of various shapes, and present results for particles self-assembly on air-liquid and liquid-liquid interfaces. In the case of non-spherical particles, the self-assembly process, while still taking place, is more complex as particles experience a torque which causes them to rotate relative to one another. This leads to a final arrangement displaying either a dominant orientation or no well-defined orientation. We also discuss the possibility of dislodging the particles from the interface by applying a strong electric field such that the Weber number is of order 1 or larger, a phenomenon which can be utilized to clean particles from liquid-fluid surfaces.     

甲壳型液晶高分子的构筑、自组装及其功能化

甲壳型液晶高分子的发展很大程度上依赖于聚合物自组装的发展,而各种可设计、可预测、可调控的自组装策略的涌现,将甲壳型液晶高分子研究推向前所未有的高度,同时也极大地丰富了高分子化学与物理的内容,提升了研究水准.研究表明,侧链"甲壳效应"在调控甲壳型液晶高分子有序结构等方面有着重要作用.本综述从甲壳型液晶高分子设计合成、液晶相态调控、嵌段共聚物自组装和功能化应用等方面,总结和评述了近年来该领域国内的最新研究进展.最后,本综述总结了甲壳型液晶高分子在发展中所面临的主要问题,并对其发展趋势进行了展望.