Nanoscience

Molecular switches have many potential applications in nanoscience and biomedicine. Transition metal complexes that can be switched from an unreactive state to an active one by a simple change in conditions (e.g. pH shift) or by binding to a specific biomolecular target - so-called target-activated metal complexes (TAMCs) - hold particular allure as a means of harnessing the potent but at times indiscriminate reactivity of metal-based drugs. We have prepared a series of ten structurally related ligands each of which bears a different pendant side-arm functional group off a common macrocyclic core...

Many have recognized the potential value of facilitating activities that span the art-science interface for the benefit of society; however, there are few examples that demonstrate how pursuit of an artistic agenda can lead to scientific insights. Here, we describe how we set out to produce an entertaining short film depicting the fertilization of the egg by sperm as a parody of a preview for another Star Wars movie to excite the public about science, but ended up developing a simulation tool for multiscale modeling...

We report the formation of naked cluster ions of silver of specific nuclearities, uncontaminated by other cluster ions, derived from monolayer-protected clusters. The hydride and phosphine co-protected cluster, [Ag18(TPP)10H16](2+) (TPP, triphenylphosphine), upon activation produces the naked cluster ion, Ag17(+), exclusively. The number of metal atoms present in the naked cluster is almost the same as that in the parent material. Two more naked cluster ions, Ag21(+) and Ag19(+), were also formed starting from two other protected clusters, [Ag25(DPPE)8H22](3+) and [Ag22(DPPE)8H19](3+), respectively (DPPE, 1,2-bis(diphenylphosphino)ethane)...

In this paper we applied transfer learning techniques for image recognition, automatic categorization, and labeling of nanoscience images obtained by scanning electron microscope (SEM). Roughly 20,000 SEM images were manually classified into 10 categories to form a labeled training set, which can be used as a reference set for future applications of deep learning enhanced algorithms in the nanoscience domain. The categories chosen spanned the range of 0-Dimensional (0D) objects such as particles, 1D nanowires and fibres, 2D films and coated surfaces, and 3D patterned surfaces such as pillars...

In recent years photodynamic therapy (PDT) has received widespread attention in cancer treatment due to its smaller surgical trauma, better selectivity towards tumor cells, reduced side effects and possibility of repeatable treatment. Since cancer is the second cause of death worldwide, scientists constantly seek for new potential therapeutic agents including nanotechnology-based photosensitizers used in PDT. The new-designed nanostructures must be carefully studied and well characterized what require analytically useful and powerful tools that enable real progress in nanoscience development...

The stability of citrate-residues on gold nanoparticles (AuNPs) against ligand displacement has been controversial. Using AuNPs synthesized with deuterated citrate in combination with in-situ surface-enhanced Raman spectroscopic (SERS) analysis, we report that both citrate-residues and solution impurities can be simultaneously adsorbed onto citrate-reduced AuNPs in solution. The citrate-residues can be readily displaced from AuNPs by organosulfur such as organothiols (RS-H), organodisuflide (R-S-S-R), and non-specific ligands including halides and adenine...

Efficient adhesion of gold thin films on dielectric or semiconductor substrates is essential in applications and research within plasmonics, metamaterials, 2D materials, and nanoelectronics. As a consequence of the relentless downscaling in nanoscience and technology, the thicknesses of adhesion layer and overlayer have reached tens of nanometers, and it is unclear if our current understanding is sufficient. In this report, we investigated how Cr and Ti adhesion layers influence the nanostructure of 2-20 nm thin Au films by means of high-resolution electron microscopy, complemented with atomic force microscopy and X-ray photoelectron spectroscopy...

Nanotechnology is a rapidly developing field because of its wide range of applications in science, nanoscience and biotechnology. Nanobiotechnology deals with nanomaterials synthesised or modified using biotechnology. Fungi are used to synthesise metal nanoparticles and they have vast applications in wound healing, pathogen detection and control, food preservation, textiles, fabrics, etc. The present review describes the different types of fungi used for the biosyntheses of silver nanoparticles (AgNPs), along with their characterisation and possible biological applications...

Thermodynamic phase behavior is affected by curved interfaces in micro- and nanoscale systems. For example, capillary freezing point depression is associated with the pressure difference between the solid and liquid phases caused by interface curvature. In this study, the thermal, mechanical, and chemical equilibrium conditions are derived for binary solid-liquid equilibrium with a curved solid-liquid interface due to confinement in a capillary. This derivation shows the equivalence of the most general forms of the Gibbs-Thomson and Ostwald-Freundlich equations...

Amphiphilic block copolymers containing polypeptides can self-assemble into a variety of nonspherical structures arising from strong interactions between peptide units. Here, we report the synthesis of a pH-responsive poly(ethyl glycol)-block-poly(l-glutamic acid)-block-poly(N-octylglycine) (PEG-b-PGA-b-PNOG) triblock copolymers by sequential ring-opening polymerization using amine-terminated poly(ethyl glycol) as the macroinitiator followed by selective deprotection of the benzyl protecting group. The obtained triblock copolymer can be directly dispersed in aqueous solution with hydrophilic PEG, pH-responsive PGA block, and hydrophobic PNOG...

Graphene-spaced magnetic systems with antiferromagnetic exchange-coupling offer exciting opportunities for emerging technologies. Unfortunately, the in-plane graphene-mediated exchange-coupling found so far is not appropriate for realistic exploitation, due to being weak, being of complex nature, or requiring low temperatures. Here we establish that ultra-thin Fe/graphene/Co films grown on Ir(111) exhibit robust perpendicular antiferromagnetic exchange-coupling, and gather a collection of magnetic properties well-suited for applications...

The universal force field (UFF) is a broadly applicable classical force field that contains parameters for almost every atom type of the periodic table. This force field is non-reactive, i.e. the topology of the system under study is considered as fixed and no creation or breaking of covalent bonds is possible. This paper introduces interactive modeling-UFF (IM-UFF), an extension of UFF that combines the possibility to significantly modify molecular structures (as with reactive force fields) with a broad diversity of supported systems thanks to the universality of UFF...

Optical trapping and manipulating of micron-sized particles have attracted enormous interests due to the potential applications in biotechnology and nanoscience. In this work, we investigate numerically and theoretically the radiation forces acting on a Rayleigh dielectric particle produced by beams generated by Gaussian mirror resonator (GMR) in the Rayleigh scattering regime. The results show that the focused beams generated by GMR can be used to trap and manipulate the particles with both high and low index of refractive near the focus point...

Understanding the nucleation and growth pathways of nanocrystallites allows precise control of the size and shape of functional crystalline nanomaterials of importance in nanoscience and nanotechnology. This paper provides a detailed analysis of the stereochemical and electronic requirements of three series of nanoclusters based on face-centered cubes (fcc) as the basic building blocks, namely, 1-, 2-, and 3-D assemblages of fcc to form superrods (n), supersquares (n(2)), and supercubes (n(3)). The generating functions for calculating the numbers (and arrangements) of surface and interior metal atoms, as well as the number and dispositions of the ligands, for these particular sequences of fcc metal clusters of the general formula [Mm(SR)l(PR'3)8](q) (where M = coinage metals; SR = thiolates (or group XI ligands), and PR'3 = phosphines) are presented...

Recent developments in nanoscience and nanotechnology intend novel and innovative applications in the food sector, which is rather recent compared with their use in biomedical and pharmaceutical applications. Nanostructured materials are having applications in various sectors of the food science comprising nanosensors, new packaging materials, and encapsulated food components. Nanostructured systems in food include polymeric nanoparticles, liposomes, nanoemulsions, and microemulsions. These materials enhance solubility, improve bioavailability, facilitate controlled release, and protect bioactive components during manufacture and storage...

A multifunctional nanoplatform, which generally integrates biosensing, imaging diagnosis, and therapeutic functions into a single nanoconstruct, has great important significance for biomedicine and nanoscience. Here, we developed a core-shell-shell multifunctional polydopamine (PDA) modified upconversion nanoplatform for intracellular tumor-related mRNAs detection and near-infrared (NIR) light triggered photodynamic and photothermal synergistic therapy (PDT-PTT). The nanoplatform was constructed by loading a silica shell on the hydrophobic upconversion nanoparticles (UCNPs) with hydrophilic photosensitizer methylene blue (MB) entrapped in it, and then modifying PDA shells through an in situ self-polymerization process, thus yielding a core-shell-shell nanoconstruct UCNP@SiO2-MB@PDA...

Large-scale fabrication of precisely defined nanostructures with tunable functions is critical to the exploitation of nanoscience and nanotechnology for production of electronic devices, energy generators, biosensors, and bionanomedicines. Although self-assembly processes have been developed to exploit biological molecules for functional materials, the resulting nanostructures and functions are still very limited, and scalable synthesis is far from being realized. Recently, we have established a bacteriophage-based biomimetic process, called 'self-templating assembly'...

With the rapid expansion of nanoscience and nanotechnology in interdisciplinary fields, multifunctional nanomaterials have attracted particular attention. Recent advances in nanotherapeutics for cancer applications provided diverse groups of synthetic particles with defined cellular and biological functions. The advance of nanotechnology significantly increased the number of possibilities for the construction of diverse biological tools. Such materials are destined to be of great importance because of the opportunity to combine the biotechnological potential of nanoparticles together with the recognition, sensitivity and modulation of cellular pathways or genes when applied to living organisms...

This paper develops a fourth model of public engagement with science, grounded in the principle of nurturing scientific agency through participatory bioethics. It argues that social media is an effective device through which to enable such engagement, as it has the capacity to empower users and transforms audiences into co-producers of knowledge, rather than consumers of content. Social media also fosters greater engagement with the political and legal implications of science, thus promoting the value of scientific citizenship...

Macromolecular crystallization has many implications in biological and materials science. Similar to the crystallization of other molecules, macromolecular crystallization conventionally considers a critical nucleus, followed by crystallographic packing of macromolecules to drive further crystal growth. Herein, we discover a distinctive macromolecular crystallization pathway by developing the concept of a macromolecular mesocrystal. This nonclassical polymer crystallization occurs through the mesoscale self-assembly of (bio)macromolecular nanocrystals...