Elucidating the insecticidal mechanisms of zein nanoparticles on Anticarsia gemmatalis (Lepidoptera: Erebidae)

Previous research suggested that positively charged zein nanoparticles [(+)ZNP] were toxic to neonates of Anticarsia gemmatalis Hübner and deleterious to noctuid pests. However, specific modes of action for ZNP have not been elucidated. Diet overlay bioassays attempted to rule out the hypothesis that A. gemmatalis mortality was caused by surface charges from component surfactants. Overlay bioassays indicated that negatively charged zein nanoparticles [(-)ZNP] and its anionic surfactant, sodium dodecyl sulfate (SDS), exhibited no toxic effects when compared to the untreated check. Nonionic zein nanoparticles [(N)ZNP] appeared to increase mortality compared to the untreated check, though larval weights were unaffected. Overlay results for (+)ZNP and its cationic surfactant, didodecyldimethylammonium bromide (DDAB), were found to be consistent with former research indicating high mortalities, and thus, dosage response curves were conducted. Concentration response tests found the LC50 for DDAB on A. gemmatalis neonates was 208.82 a.i./ml. To rule out possible antifeedant capabilities, dual choice assays were conducted. Results indicated that neither DDAB nor (+)ZNP were antifeedants, while SDS reduced feeding when compared to other treatment solutions. Oxidative stress was tested as a possible mode of action, with antioxidant levels used as a proxy for reactive oxygen species (ROS) in A. gemmatalis neonates, which were fed diet treated with different concentrations of (+)ZNP and DDAB. Results indicated that both (+)ZNP and DDAB decreased antioxidant levels compared to the untreated check, suggesting that both (+)ZNP and DDAB may inhibit antioxidant levels. This paper adds to the literature on potential modes of action by biopolymeric nanoparticles.

From passive to emerging smart silicones

Amassing remarkable properties, silicones are practically indispensable in our everyday life. In most classic applications, they play a passive role in that they cover, seal, insulate, lubricate, water-proof, weather-proof etc. However, silicone science and engineering are highly innovative, seeking to develop new compounds and materials that meet market demands. Thus, the unusual properties of silicones, coupled with chemical group functionalization, has allowed silicones to gradually evolve from passive materials to active ones, meeting the concept of “smart materials”, which are able to respond to external stimuli. In such cases, the intrinsic properties of polysiloxanes are augmented by various chemical modifications aiming to attach reactive or functional groups, and/or by engineering through proper cross-linking pattern or loading with suitable fillers (ceramic, magnetic, highly dielectric or electrically conductive materials, biologically active, etc.), to add new capabilities and develop high value materials. The literature and own data reflecting the state-of-the art in the field of smart silicones, such as thermoplasticity, self-healing ability, surface activity, electromechanical activity and magnetostriction, thermo-, photo-, and piezoresponsivity are reviewed.

Self-Assembly of Au–Ag Alloy Hollow Nanochains for Enhanced Plasmon-Driven Surface-Enhanced Raman Scattering

In this paper, Au–Ag alloy hollow nanochains (HNCs) were successfully prepared by a template-free self-assembly method achieved by partial substitution of ligands. The obtained Au–Ag alloy HNCs exhibit stronger enhancement as surface-enhanced Raman scattering (SERS) substrates than Au–Ag alloy hollow nanoparticles (HNPs) and Au nanochains substrates with an intensity ratio of about 1.3:1:1. Finite difference time domain (FDTD) simulations show that the SERS enhancement of Au–Ag alloy HNCs substrates is produced by a synergistic effect between the plasmon hybridization effect associated with the unique alloy hollow structure and the strong “hot spot” in the interstitial regions of the nanochains.

Triggering gold nanoparticles formation on a quartz surface by nanosecond pulsed laser irradiation

A new direct and straightforward method is proposed to synthesize bare Au nanoparticles (Au NPs) on a quartz surface by nanosecond 532 nm pulsed laser irradiation of a quartz surface in contact with Au(iii) precursor solution. The characterisation by XPS, UV-Vis, SEM and AFM measurements demonstrate the formation of bare Au NPs anchored on the quartz surface with a mean height of 27 ± 10 nm localized in the laser irradiation area. The main features of this approach are their simplicity, quick fabrication and the large surface area covered by Au NPs. The absence of ligands/stabilizing agents on the Au NPs makes this substrate very suitable for its direct surface modification opening the range of applications in biology, medicine, sensing, catalysis, among others. As a proof of concept, the capabilities and advantages of this substrate as Surface Enhanced Raman Spectroscopy (SERS) platform were tested demonstrating the absence of any Raman signal overlapping with the analyte in the whole spectral range.

In situtailoring the morphology of In(OH)3nanostructures via surfactants during anodization and their transformation into In2O3nanoparticles

The present work reports the effect of various surfactants on the morphology of In(OH)₃nanostructures prepared via anodization. In-sheets were anodized in an environmentally benign electrolyte containing a small quantity of CTAB, CTAC, and PDDA surfactants at room temperature. The produced nanostructures were characterized using XRD, HRTEM, SAED, and EDAX. The morphology of indium hydroxide (In(OH)₃) nanostructures was successfully tailoredin situwith the help of surfactants in 1 M KCl aqueous electrolyte. XRD results confirmed the formation of In(OH)₃and indium oxyhydroxide (InOOH) nanostructures in the pristine form which were transformed into single-phase cubic In₂O₃nanoparticles (NPs) after calcination. HRTEM analyses showed that the morphology and size of the In(OH)₃nanostructures can be tuned to form nanorods, nanosheets and nanostrips using different surfactants. The results revealed that CTAC and PDDA surfactants have a profound effect on the morphology of In(OH)₃nanostructure compared to CTAB due to the higher concentration of Cl^-ion. The possible mechanism of surfactants effect on the morphology is proposed. Furthermore, annealing converted the In(OH)₃nanostructures into spherical In₂O₃NPs with uniform and homogeneous size. We anticipate that the morphology of other metal-oxides nanostructure can be tuned using this simple, facile and rapid technique. In₂O₃NPs prepared without and with CTAB surfactant were further explored for the non-enzymatic detection of hydrogen peroxide (H₂O₂). Electrochemical measurements showed enhanced electrocatalytic performance with fast electron transfer (∼2s) between the redox centers of H₂O₂and electrode surface. The In₂O₃NPs prepared using CTAB/Au electrode exhibited about 4-fold increase in sensitivity compared to the bare Au electrode. The biosensor also demonstrated good reproducibility, higher selectivity, and increased shelf life.

A review of the role and mechanism of surfactants in the morphology control of metal nanoparticles

Although great progress has been made in the synthesis of metal nanoparticles, good repeatability and accurate predictability are still difficult to achieve. This difficulty can be attributed to the synthetic method based primarily on observation and subjective experience, and the role of many surfactants remains unclear. It should be noted that surfactants play an important role in the synthetic process. Understanding their function and mechanism in the synthetic process is a prerequisite for the rational design of nanocatalysts with ideal morphology and performance. In this review article, the function of surfactants is introduced first, and then the mechanism of action of surfactants in controlling the morphology of nanoparticles is discussed according to the types of surfactants, and the promoting and sealing effects of surfactants on the crystal surface is revealed. The relationship between surfactants and the morphology structure of nanoparticles is studied. The removal methods of surfactants are discussed, and the existing problems in the current development strategy are summarized. Finally, the application of surfactants in controlling the morphology of metal nanocrystals is prospected. It is hoped that the review can open up new avenues for the synthesis of nanocrystals.

In-situ green synthesis of fluorescent silica-silver conjugate nanodendrites using nanoporous frustules of diatoms: an unprecedented approach

Generally, nanodendrite synthesis is chemical mediated and expensive. The biogenesis of such hierarchical structures is still in its nascent stage. The present study aimed at exploiting the nanoporous frustules of Halamphora subturgida, as a source of biosilica for the biosynthesis and stabilization of conjugate nanodendrites of silica and silver. These minute diatom frustules when exposed to 9 mM of silver nitrate solution, a highly crystalline nanohybride dendrites were synthesized. The nanohybrid dendrite synthesis was initially confirmed by the formation of greyish-brown frustules after 72 h of exposure. The composite dendrites were thoroughly characterized by standard techniques. Electron microscopic images illustrated that the process began with the formation of isotropic hybrid nanospheres with an internal diameter of 20 nm and continued to develop anisotropic nanocrystals with time. The nanodendrites externally formed on the siliceous frustules, acting as a template for the former. They were characterized by distinct 100 nm wide and 1-2 µm long trunks and 70-100 nm wide and 220-220 nm long branches on either side of the trunk. The optical measurement revealed the fluorescence property of the nanostructures owing to the photoluminescent efficiency of the frustules. Both the externally derived hybrid nanodendrites and internally synthesized nanospheres possessed superior stability in the suspension with a zeta potential value of - 35.7 mV and - 24.8 mV, respectively. Thus, this method is eco-friendly and provides a new dimension for nanodendrite synthesis with minimal cost and maximal yield compared to its non-biologically synthesized counterparts that involve several other drawbacks like chemical hazards and high energy consumption.

Adhesion and Aggregation of Spherical Nanoparticles on Lipid Membranes

We present a review of recent results on the adhesion, wrapping and aggregation of spherical nanoparticles (NPs) on lipid membranes via molecular dynamics simulations of an implicit solvent model. We show that the degree of wrapping of small NPs, by tensionless planar membranes, can increase continuously with the adhesion strength. However, the degree of wrapping exhibits a discontinuity for large NPs or short interaction range. The adhesion of NPs to small vesicles, without volume constraint, also exhibits a discontinuity between weakly wrapped states and fully endocytosed states. Multiple spherical NPs, bound to tensionless planar membranes are either in a gas state, at weak adhesion strength, or aggregate, at relatively high adhesion strength, into a multitude of structures, corresponding to in-plane chains, out-of-plane tubes and rings, and out-of-plane single-chain tubes. Annealing scans and free energy calculations show that the gas and tube phases are the predominantly stable phases. In-plane chains are only stable for small aggregates and the out-of-plane bitubes are long-lived metastable states.

Phase Diagrams and Structural Characterization of Mixtures of Silicone Surfactants + Silicone Oils + Water

Silicone surfactants display unique properties and are widely employed in pharmaceutical and cosmetic products. In this work, we study water incorporation into silicone oils using silicone surfactants. Despite their importance, there are only a few studies reporting their phase equilibrium and structural characterization. Here, we determined the phase diagram of systems containing silicone oils, silicone surfactants, and water. In particular, we investigated the self-assembly behavior of two siloxane surfactants with the different hydrophilic-lipophilic balance: M(D'E₇OH)M and MD₁₈(D'₃E₁₈OAc)M and two silicone oils (cyclic oil-D₄ and linear oil-MD₁₅M). The phase behavior of the mixtures was investigated through optical inspection and structural characterization of aggregated states (microemulsions and mesophases) using small angle X-ray scattering (SAXS). These water-in-oil microemulsions or bicontinuous microemulsions incorporated a maximum amount of approximately 20 wt % water for the two surfactants with cyclic oil. A similar behavior was also identified with linear silicone oil, though with smaller water contents. We also observed the formation of anisotropic states, with a predominance of lamellar phases and a small region of a hexagonal phase. A quantitative analysis of the SAXS curves in the lamellar region reveals that this mesophase swells continuously after the addition of water lamellar periods ranging from 50 Å (with 18 wt % water) to 64 Å (with 40 wt % water). Our results confirm and expand the earlier literature on similar compounds, indicating their potential in incorporating water into silicone mixtures and forming interesting mesophases. Accompanying this characterization, we also report a comprehensive and systematic set of structural details for the different systems (microemulsions, bicontinuous phases and mesophases) formed by these mixtures, derived from the SAXS measurements.

Directed assembly of magnetic and semiconducting nanoparticles with tunable and synergistic functionality

The ability to fabricate new materials using nanomaterials as building blocks, and with meta functionalities, is one of the most intriguing possibilities in the area of materials design and synthesis. Semiconducting quantum dots (QDs) and magnetic nanoparticles (MNPs) are co-dispersed in a liquid crystalline (LC) matrix and directed to form self-similar assemblies by leveraging the host's thermotropic phase transition. These co-assemblies, comprising 6 nm CdSe/ZnS QDs and 5-20 nm Fe₃O₄ MNPs, bridge nano- to micron length scales, and can be modulated in situ by applied magnetic fields <250 mT, resulting in an enhancement of QD photoluminescence (PL). This effect is reversible in co-assemblies with 5 and 10 nm MNPs but demonstrates hysteresis in those with 20 nm MNPs. Transmission electron microscopy (TEM) and energy dispersive spectroscopy reveal that at the nanoscale, while the QDs are densely packed into the center of the co-assemblies, the MNPs are relatively uniformly dispersed through the cluster volume. Using Lorentz TEM, it is observed that MNPs suspended in LC rotate to align with the applied field, which is attributed to be the cause of the observed PL increase at the micro-scale. This study highlights the critical role of correlating multiscale spectroscopy and microscopy characterization in order to clarify how interactions at the nanoscale manifest in microscale functionality.

Stability of membrane-induced self-assemblies of spherical nanoparticles

The self-assembly of spherical nanoparticles, resulting from their adhesion on tensionless lipid membranes, is investigated through molecular dynamics simulations of a coarse-grained implicit-solvent model. Our simulations indicate that, with increasing adhesion strength, while reshaping the membrane, the nanoparticles aggregate into a sequence of self-assemblies corresponding to in-plane chains, two-row tubular (bitube) chains, annular (ring) chains, and single-row tubular (tube) chains. Annealing scans, with respect to adhesion strength, show that the transitions between the various phases are highly first-order with significant hystereses. Free energy calculations indicate that the gas and single-row tubular chains are stable over wide ranges of adhesion strength. In contrast, the in-plane chains are only stable for small aggregates of NPs, and the bitube and ring chains are long-lived metastable states over a wide range of adhesion strength.

Simple size-controlled synthesis of Au nanoparticles and their size-dependent catalytic activity

The controlled preparation of Au nanoparticles (NPs) in the size range of 6 to 22 nm is explored in this study. The Au NPs were prepared by the reduction of tetrachloroauric acid using maltose in the presence of nonionic surfactant Tween 80 at various concentrations to control the size of the resulting Au NPs. With increasing concentration of Tween 80 a decrease in the size of produced Au NPs was observed, along with a significant decrease in their size distribution. The size-dependent catalytic activity of the synthesized Au NPs was tested in the reduction of 4-nitrophenol with sodium borohydride, resulting in increasing catalytic activity with decreasing size of the prepared nanoparticles. Eley-Rideal catalytic mechanism emerges as the more probable, in contrary to the Langmuir-Hinshelwood mechanism reported for other noble metal nanocatalysts.

Plasmon-actuated nano-assembled microshells

We present three-dimensional microshells formed by self-assembly of densely-packed 5 nm gold nanoparticles (AuNPs). Surface functionalization of the AuNPs with custom-designed mesogenic molecules drives the formation of a stable and rigid shell wall, and these unique structures allow encapsulation of cargo that can be contained, virtually leakage-free, over several months. Further, by leveraging the plasmonic response of AuNPs, we can rupture the microshells using optical excitation with ultralow power (<2 mW), controllably and rapidly releasing the encapsulated contents in less than 5 s. The optimal AuNP packing in the wall, moderated by the custom ligands and verified using small angle x-ray spectroscopy, allows us to calculate the heat released in this process, and to simulate the temperature increase originating from the photothermal heating, with great accuracy. Atypically, we find the local heating does not cause a rise of more than 50 °C, which addresses a major shortcoming in plasmon actuated cargo delivery systems. This combination of spectral selectivity, low power requirements, low heat production, and fast release times, along with the versatility in terms of identity of the enclosed cargo, makes these hierarchical microshells suitable for wide-ranging applications, including biological ones.

Noble-metal Ag nanoparticle chains: annealing Ag/Bi superlattice nanowires in vacuum

One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10(-5) Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

Highly effective and uniform SERS substrates fabricated by etching multi-layered gold nanoparticle arrays

Gold nanoparticle multilayers printed on silicon substrates layer by layer were etched by a gold etchant to form highly effective and uniform substrates for surface-enhanced Raman scattering (SERS). The performance of the SERS substrates was systematically studied by adjusting the number of nanoparticle layers and the etching time. The optimized enhancement factor (EF) and the detection limit of the substrates were determined to be 8.6 × 10(6) and 1 × 10(-12) M, respectively. The high EF and low detection limit were attributed to the high density of "hot-spots" and the facile accession of probe molecules to these spots. Moreover, the SERS substrates exhibited a nice uniformity with a small spot-to-spot variation and a good sample-to-sample reproducibility as well. The experimental results were supported by finite-difference time domain (FDTD) simulations. Our study suggests that low-cost, large-scale, and uniform SERS substrates with a high EF and low detection limit can be achieved by using bottom-up chemical methods.

Stable monodisperse colloidal spherical gold nanoparticles formed by an imidazolium gemini surfactant-based water-in-oil microemulsion with excellent catalytic performance

A facile and versatile method for the synthesis of stable monodisperse colloidal gold nanoparticles was developed using a water-in-oil microemulsion-templating strategy.

Plasmonic nanohalo optical probes for highly sensitive imaging of survivin mRNA in living cells

A novel strategy for sensitive detection of survivin mRNA based on Rayleigh light scattering spectroscopy of AuNP nanohalo probes.

Differential role of PVP on the synthesis of plasmonic gold nanostructures and their catalytic and SERS properties

Differential role of PVP modified with halide ions has been meticulously studied for in situ tuning of Au nanoparticle growth utilizing XRD measurements together with FTIR data, thus quantifying their catalysis and SERS applications.

Supramolecular structures ranging from nano- to macro-scale with fluorescent and organic semiconducting properties

Supramolecular structures ranging from nano- to macro-scale are prepared by an ionic self-assembly (ISA) strategy with commercially available, low-cost dyes and surfactants, viz. Rhodamine 6G (R6G) and sodium bis(2-ethylhexylhexyl) sulfosuccinate (NaAOT).

Hyperbranched polymer-gold nanoparticle assemblies: role of polymer architecture in hybrid assembly formation and SERS activity

Plasmonic gold nanoassemblies that self-assemble with the aid of linking molecules or polymers have the potential to yield controlled hierarchies of morphologies and consequently result in materials with tailored optical (e.g., localized surface plasmon resonances (LSPR)) and spectroscopic properties (e.g., surface-enhanced Raman scattering (SERS)). Molecular linkers that are structurally well-defined are promising for forming hybrid nanoassemblies which are stable in aqueous solution and are increasingly finding application in nanomedicine. Despite much ongoing research in this field, the precise role of molecular linkers in governing the morphology and properties of the hybrid nanoassemblies remains unclear. Previously we have demonstrated that branched linkers, such as hyperbranched polymers, with specific anchoring end groups can be successfully employed to form assemblies of gold NPs demonstrating near-infrared SPRs and intense SERS scattering. We herein introduce a tailored polymer as a versatile molecular linker, capable of manipulating nanoassembly morphologies and hot-spot density. In addition, this report explores the role of the polymeric linker architecture, specifically the degree of branching of the tailored polymer in determining the formation, morphology, and properties of the hybrid nanoassemblies. The degree of branching of the linker polymer, in addition to the concentration and number of anchoring groups, is observed to strongly influence the self-assembly process. The assembly morphology shifts primarily from 1D-like chains to 2D plates and finally to 3D-like globular structures, with increase in degree of branching of the macromolecular linker. Insights have been gained into how the morphology influences the SERS performance of these nanoassemblies with respect to hot-spot density. These findings supplement the understanding of the morphology determining nanoassembly formation and pave the way for the possible application of these nanoassemblies as SERS biosensors for medical diagnostics.

Bottom-up molecular-assembly of Ru(ii)polypyridyl complex-based hybrid nanostructures decorated with silver nanoparticles: effect of Ag nitrate concentration

Facile and templateless one-pot synthesis of Ru(ii)polypyridyl complex-based hybrid nanostructures decorated with silver nanoparticles (Ag NPs) with variable morphologies.

Self assembly of plasmonic core–satellite nano-assemblies mediated by hyperbranched polymer linkers

The morphology of plasmonic nano-assemblies has a direct influence on optical properties, such as localised surface plasmon resonance (LSPR) and surface enhanced Raman scattering (SERS) intensity.

Self-assembled hyperbranched polymer-gold nanoparticle hybrids: understanding the effect of polymer coverage on assembly size and SERS performance

In the past few years, remarkable progress has been made in unveiling novel and unique optical properties of strongly coupled plasmonic nanostructures. However, the application of such plasmonic nanostructures in biomedicine remains challenging because of the lack of facile and robust assembly methods for producing stable nanostructures. Previous attempts to achieve plasmonic nanoassemblies using molecular ligands were limited by the lack of flexibility that could be exercised in forming them. Here, we report the utilization of tailor-made hyperbranched polymers (HBP) as linkers to assemble gold nanoparticles (NPs) into nanoassemblies. The ease and flexibility in tuning the particle size and number of branch ends of an HBP make it an ideal candidate as a linker, as opposed to DNA, small organic molecules, and linear or dendrimeric polymers. We report a strong correlation of polymer (HBP) concentration with the size of the hybrid nanoassemblies and "hot-spot" density. We have shown that such solutions of stable HBP-gold nanoassemblies can be barcoded with various Raman tags to provide improved surface-enhanced Raman scattering (SERS) compared to that of nonaggregated NP systems. These Raman-barcoded hybrid nanoassemblies, with further optimization of the NP shape, size, and hot-spot density, may find application as diagnostic tools in nanomedicine.

Fabrication and spectroscopic investigation of branched silver nanowires and nanomeshworks

Wide wavelength ranges of light localization and scattering characteristics can be attributed to shape-dependent longitude surface plasmon resonance in complicated nanostructures. We have studied this phenomenon by spectroscopic measurement and a three-dimensional numerical simulation, for the first time, on the high-density branched silver nanowires and nanomeshworks at room temperature. These nanostructures were fabricated with simple light-induced colloidal method. In the range from the visible to the near-infrared wavelengths, light has been found effectively trapped in those trapping sites which were randomly distributed at the corners, the branches, and the junctions of the nanostructures in those nanostructures in three dimensions. The broadened bandwidth electromagnetic field enhancement property makes these branched nanostructures useful in optical processing and photovoltaic applications.

Protein-decorated reduced oxide graphene composite and its application to SERS

A globular protein, β-lactoglobulin (BLG), was used to decorate reduced graphene oxide sheets (RGO) and the obtained BLG-RGO composite can be dispersed in aqueous solution with pH-sensitive solubility. The morphology of the BLG-RGO composite was studied by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results indicate that BLG-RGO is effectively exfoliated with an average thickness of 2.5 nm. UV-vis spectra were performed to examine the reduction degree and determine the optimum concentration of β-lactoglobulin and appropriate pH value. Furthermore, Raman spectra demonstrate that β-Lactoglobulin promotes the chemical reduction process of graphene oxide and benefits to repair the crystal defects. Due to the adsorption of β-Lactoglobulin on the surface of graphene sheets, the BLG-RGO composite was further used as template for Au nanoparticles assembly. These Au nanoparticles assembled on the BLG-RGO composite were shown to yield a large SERS enhancement for Rhodamine 6G.

The effects of the π-π stacking interactions on the patterns of gold nanoparticles formed at the air-water interface

Benzyl-n-hexadecyl dimethylammonium chloride (BHDC) monolayer-stabilized gold nanoparticles were synthesized in a two-phase liquid-liquid system and found to self-assemble into varied structures under the control of temperature at the air-water interface. It has been demonstrated that the π-π stacking interactions between the capping agent molecules significantly affect the formation of the unique patterns. A possible mechanism based on Marangoni-Bénard convection in the evaporating droplets and π-π stacking interactions was proposed. Four surfactants with similar structures: N-hexadecyl-N-methylpyrrolidinium bromide (C(16)MPB), 1-hexadecyl-3-methylimidazolium bromide (C(16)mimBr), 1-(2,4,6-trimethylphenyl)-3-hexadecylimidazolium bromide (C(16)pimBr) and hexadecyltrimethylammonium bromide (CTAB) were also used to further verify the formation mechanism mentioned above.

Formation of Ag nanostrings induced by lyotropic liquid-crystalline phospholipid multilayer

Morphological variation of the Ag nanoparticles embedded in a lyotropic phospholipid (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, DOPE) membrane during hydration was investigated. Hydration at 5 °C resulted in transformation of the Ag nanoparticles into a bundle of Ag nanostrings as the Ag nanoparticles conformed to the H(II) phase of the DOPE molecules. Above 30 °C, the nanoparticles quickly coarsened into large polygonal-shaped particles since high mobility of the lipid molecules overwhelmed the tendency for the Ag nanoparticles to order. The result provided an insight into the long-term stability of nanoparticles trapped in different lipid membranes depending on the structural ordering of the molecules.