Modifying Thermal Switchability of Liquid Crystalline Nanoparticles by Alkyl Ligands Variation

Nanoparticle-mediated dsRNA delivery for precision insect pest control: a comprehensive review

Nanoparticle-based delivery systems have emerged as powerful tools in the field of pest management, offering precise and effective means of delivering double-stranded RNA (dsRNA), a potent agent for pest control through RNA interference (RNAi). This comprehensive review aims to evaluate and compare various types of nanoparticles for their suitability in dsRNA delivery for pest management applications. The review begins by examining the unique properties and advantages of different nanoparticle materials, including clay, chitosan, liposomes, carbon, gold and silica. Each material's ability to protect dsRNA from degradation and its potential for targeted delivery to pests are assessed. Furthermore, this review delves into the surface modification strategies employed to enhance dsRNA delivery efficiency. Functionalization with oligonucleotides, lipids, polymers, proteins and peptides is discussed in detail, highlighting their role in improving stability, cellular uptake, and specificity of dsRNA delivery.This review also provides valuable guidance on choosing the most suitable nanoparticle-based system for delivering dsRNA effectively and sustainably in pest management. Moreover, it identifies existing knowledge gaps and proposes potential research directions aimed at enhancing pest control strategies through the utilization of nanoparticles and dsRNA.

Tuneable Plasmonic Resonances Of A Dynamic Thin Film Of Ultrasmall Nanocrystals Modified In the Anti-Galvanic Reduction Process

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.

Unconventional-Phase Crystalline Materials Constructed from Multiscale Building Blocks

Crystal phase, an intrinsic characteristic of crystalline materials, is one of the key parameters to determine their physicochemical properties. Recently, great progress has been made in the synthesis of nanomaterials with unconventional phases that are different from their thermodynamically stable bulk counterparts via various synthetic methods. A nanocrystalline material can also be viewed as an assembly of atoms with long-range order. When larger entities, such as nanoclusters, nanoparticles, and microparticles, are used as building blocks, supercrystalline materials with rich phases are obtained, some of which even have no analogues in the atomic and molecular crystals. The unconventional phases of nanocrystalline and supercrystalline materials endow them with distinctive properties as compared to their conventional counterparts. This Review highlights the state-of-the-art progress of nanocrystalline and supercrystalline materials with unconventional phases constructed from multiscale building blocks, including atoms, nanoclusters, spherical and anisotropic nanoparticles, and microparticles. Emerging strategies for engineering their crystal phases are introduced, with highlights on the governing parameters that are essential for the formation of unconventional phases. Phase-dependent properties and applications of nanocrystalline and supercrystalline materials are summarized. Finally, major challenges and opportunities in future research directions are proposed.

Size-Dependent Thermo- and Photoresponsive Plasmonic Properties of Liquid Crystalline Gold Nanoparticles

Achieving remotely controlled, reversibly reconfigurable assemblies of plasmonic nanoparticles is a prerequisite for the development of future photonic technologies. Here, we obtained a series of gold-nanoparticle-based materials which exhibit long-range order, and which are controlled with light or thermal stimuli. The influence of the metallic core size and organic shell composition on the switchability is considered, with emphasis on achieving light-responsive behavior at room temperature and high yield production of nanoparticles. The latter translates to a wide size distribution of metallic cores but does not prevent their assembly into various, switchable 3D and 2D long-range ordered structures. These results provide clear guidelines as to the impact of size, size distribution, and organic shell composition on self-assembly, thus enhancing the smart design process of multi-responsive nanomaterials in a condensed state, hardly attainable by other self-assembly methods which usually require solvents.

Shaping Liquid Crystals with Gold Nanoparticles: Helical Assemblies with Tunable and Hierarchical Structures Via Thin-Film Cooperative Interactions

The availability of helical assemblies of plasmonic nanoparticles with precisely controlled and tunable structures can play a key role in the future development of chiral plasmonics and metamaterials. Here, a strategy to efficiently yield helical structures based on the cooperative interactions of liquid crystals and gold nanoparticles in thin films is developed. These nanocomposites exhibit exceptional long-range hierarchical order across length scales, which results from the growth mechanism of nanoparticle-coated twisted nanoribbons and their ability to form organized bundles. The helical assembly formation is governed by the presence of rationally functionalized nanoparticles. Importantly, the thickness of the achieved nanocomposites can be reversibly reconfigured owing to the polymorphic nature of the liquid crystal. The versatility of the proposed approach is demonstrated by preparing helices assembled from nanoparticles of different geometries and dimensions (spherical and rod-like). The described strategy may become an enabling technology for structuring nanoparticle assemblies with high precision and fabricating optically active materials.