Antimicrobials: An update on new strategies to diversify treatment for bacterial infections.

Ninety-five years after Fleming's discovery of penicillin, a bounty of antibiotic compounds have been discovered, modified, or synthesised. Diversification of target sites, improved stability and altered activity spectra have enabled continued antibiotic efficacy, but overwhelming reliance and misuse has fuelled the global spread of antimicrobial resistance (AMR). An estimated 1.

Self-assembling ferritin nanoplatform for the development of infectious hematopoietic necrosis virus vaccine.

Self-assembling protein nanoparticles are used as a novel vaccine design platform to improve the stability and immunogenicity of safe subunit vaccines, while providing broader protection against viral infections. Infectious Hematopoietic Necrosis virus (IHNV) is the causative agent of the WOAH-listed IHN diseases for which there are currently no therapeutic treatments and no globally available commercial vaccine. In this study, by genetically fusing the virus glycoprotein to the H.

Versailles project on advanced materials and standards (VAMAS) interlaboratory study on measuring the number concentration of colloidal gold nanoparticles.

We describe the outcome of a large international interlaboratory study of the measurement of particle number concentration of colloidal nanoparticles, project 10 of the technical working area 34, "Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS). A total of 50 laboratories delivered results for the number concentration of 30 nm gold colloidal nanoparticles measured using particle tracking analysis (PTA), single particle inductively coupled plasma mass spectrometry (spICP-MS), ultraviolet-visible (UV-Vis) light spectroscopy, centrifugal liquid sedimentation (CLS) and small angle X-ray scattering (SAXS). The study provides quantitative data to evaluate the repeatability of these methods and their reproducibility in the measurement of number concentration of model nanoparticle systems following a common measurement protocol.

In depth characterisation of the biomolecular coronas of polymer coated inorganic nanoparticles with differential centrifugal sedimentation.

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids.

Influence of Size and Shape on the Anatomical Distribution of Endotoxin-Free Gold Nanoparticles.

The transport and the delivery of drugs through nanocarriers is a great challenge of pharmacology. Since the production of liposomes to reduce the toxicity of doxorubicin in patients, a plethora of nanomaterials have been produced and characterized. Although it is widely known that elementary properties of nanomaterials influence their in vivo kinetics, such interaction is often poorly investigated in many preclinical studies.

Mapping protein binding sites on the biomolecular corona of nanoparticles.

Nanoparticles in a biological milieu are known to form a sufficiently long-lived and well-organized 'corona' of biomolecules to confer a biological identity to the particle. Because this nanoparticle-biomolecule complex interacts with cells and biological barriers, potentially engaging with different biological pathways, it is important to clarify the presentation of functional biomolecular motifs at its interface. Here, we demonstrate that by using antibody-labelled gold nanoparticles, differential centrifugal sedimentation and various imaging techniques it is possible to identify the spatial location of proteins, their functional motifs and their binding sites.

Revealing DNA interactions with exogenous agents by surface-enhanced Raman scattering.

The standard protocols for DNA analysis largely involve polymerase chain reaction (PCR). However, DNA structures bound to chemical agents cannot be PCR-amplified, and therefore any sequence changes induced by external agents may be neglected. Thus, the development of analytical tools capable of characterizing the biochemical mechanisms associated with chemically induced DNA damage is demanded for the rational design of more effective chemotherapy drugs, understanding the mode of actions of carcinogenic chemicals, and monitoring the genotypic toxicology of environments.

Direct surface-enhanced Raman scattering analysis of DNA duplexes.

The exploration of the genetic information carried by DNA has become a major scientific challenge. Routine DNA analysis, such as PCR, still suffers from important intrinsic limitations. Surface-enhanced Raman spectroscopy (SERS) has emerged as an outstanding opportunity for the development of DNA analysis, but its application to duplexes (dsDNA) has been largely hampered by reproducibility and/or sensitivity issues.

Interactions of gold nanoparticles with a phospholipid monolayer membrane on mercury.

It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed to a hanging mercury drop electrode can serve as a simple electrochemical model system to study biomembrane penetration by gold nanoparticles. The hydrogen redox-chemistry characteristic of ligand-stabilized gold nanoparticles in molecularly close contact with a mercury electrode is used as an indicator of membrane penetration. Results for water-dispersible gold nanoparticles of two different sizes are reported, and comparisons are made with the cellular uptake of the same preparations of nanoparticles by a common human fibroblast cell line.

Nanomaterials: impact on cells and cell organelles.

Colloidal nanoparticles designed for the interactions with cells are very small, nanoscale objects usually consisting of inorganic cores and organic shells that are dispersed in a buffer or biological medium. By tuning the material properties of the nanoparticles a number of different biological applications of nanomaterials are enabled i.e.

Preparation and characterization of Au nanoparticles capped with mercaptocarboranyl clusters.

The preparation of 3-4 nm and 10 nm gold nanoparticles capped with neutral carborane-based mercaptocarboranes, via two different preparative routes, is reported. The resulting boron-enriched nanomaterials exhibit complete dispersibility in water, opening the way for the use of these monolayer protected clusters (MPCs) in medical applications, such as boron neutron capture therapy (BNCT). These newly prepared MPCs have been characterized by FTIR, (1)H and (11)B NMR spectroscopy, UV-visible, centrifugal particle sizing (CPS), and, in some cases, inductively coupled plasma atomic emission spectrometry (ICP-AES).

High-resolution sizing of monolayer-protected gold clusters by differential centrifugal sedimentation.

Differential centrifugal sedimentation (DCS) has been applied to accurately size ligand-protected gold hydrosols in the 10 to 50 nm range. A simple protocol is presented to correct for particle density variations due to the presence of the ligand shell, which is formed here by either polyethylene glycol-substituted alkane thiols (PEG-alkane thiols) of different chain length or oligopeptides. The method gives reliable data for all particle sizes investigated and lends itself to rapid routine sizing of nanoparticles.

Directed assembly of DNA-functionalized gold nanoparticles using pyrrole-imidazole polyamides.

Traditional methods for the construction of nanoparticle arrays and lattices exploit Watson-Crick base pairing of single-stranded DNA sequences as a proxy for self-assembly. Although this approach has been utilized in a variety of applications in nanoassembly, diagnostics, and biomedicine, the diversity of this recognition lexicon could be considerably increased by developing strategies that recognize the base-pairing landscape of double-stranded DNA (dsDNA) sequences. Herein we describe the first report of programmed gold nanoparticle (GNP) aggregation directed by the recognition of dsDNA sequences using pyrrole-imidazole polyamide-GNP (PA-GNP) conjugates.

Positively charged silver nanoparticles and their effect on surface-enhanced Raman scattering of dye-labelled oligonucleotides.

Improved positively charged nanoparticles are described to provide a simplified SERS substrate for DNA detection. Complete flocculation of the nanoparticles is prevented due to the controlled analyte induced aggregation. This provides a stable aggregation state which significantly extends the analysis window simplifying DNA detection by SERS.

Importance of nanoparticle size in colorimetric and SERS-based multimodal trace detection of Ni(II) ions with functional gold nanoparticles.

Colorimetric detection of analytes using gold nanoparticles along with surface-enhanced Raman spectroscopy (SERS) are areas of intense research activity since they both offer sensing of very low concentrations of target species. Multimodal detection promotes the simultaneous detection of a sample by a combination of different techniques; consequently, surface chemistry design in the development of multimodal nanosensors is important for rapid and sensitive evaluation of the analytes by diverse analytical methods. Herein it is shown that nanoparticle size plays an important role in the design of functional nanoparticles for colorimetric and SERS-based sensing applications, allowing controlled nanoparticle assembly and tunable sensor response.

Mercaptocarborane-capped gold nanoparticles: electron pools and ion traps with switchable hydrophilicity.

A simple single-phase method for the preparation of ca. 2 nm gold nanoparticles capped with mercaptocarborane ligands is introduced. The resultant monolayer protected clusters (MPCs) exhibit redox-dependent solubility and readily phase transfer between water and nonpolar solvents depending on the electronic and ionic charge stored in the metal core and in the ligand shell, respectively.

Intracellular mapping with SERS-encoded gold nanostars.

Here we report on the design, synthesis and application of small, highly bright, star-shaped SERS encoded single nanoparticles with the ability of providing an optical signal upon excitation with near infrared light. These particles are colloidally stable, fully biocompatible and can be internalized into living cells for intracellular imaging.

Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.

This paper contributes to the debate on how nanosized objects negotiate membrane barriers inside biological cells. The uptake of peptide-modified gold nanoparticles by HeLa cells has been quantified using atomic emission spectroscopy. The TAT peptide from the HIV virus was singled out as a particularly effective promoter of cellular uptake.

Inflicting controlled nonthermal damage to subcellular structures by laser-activated gold nanoparticles.

We show that low-intensity laser irradiation of cancer cells containing endosomal gold nanoparticles leads to endosome rupture and escape of the nanoparticles into the cytosol without affecting the cells' viability. The low light intensity of our experiments allows us to rule out photothermal effects as the underlying mechanism, and we present results that suggest photoinduced radicals as the photogenerated active species. This nonthermal mechanism may also be important in the context of cell death at higher laser intensities, which had been reported previously.

Phagocytosis of biocompatible gold nanoparticles.

We report the evidence for the cellular uptake of gold nanoparticles via the phagocytosis mechanism in murine macrophage cells strongly supported by TEM and optical microscopy. Nanoparticles were prepared using several biocompatible molecules of choice (5-aminovaleric acid, l-DOPA, melatonin, and serotonin hydrochloride) as stabilizers for gold colloids. Their surface chemistry was fully characterized by UV-vis, ATR-FTIR, (1)H NMR, and HR-MAS (1)H NMR spectroscopies, and size distribution was determined by CPS disc centrifuge and TEM.

Gold nanoparticles prepared using cape aloe active components.

A novel use of two components of Cape aloe, aloin A and aloesin, acting as stabilizers in the preparation of gold and silver nanoparticles, is reported. Stable water-soluble particles of different size and shape are prepared by varying the reaction conditions, temperature, reaction time, and reducing agents. Characterization of the obtained particles is performed using UV-visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and 1H NMR spectroscopies and transmission electron microscopy (TEM).

A multidentate peptide for stabilization and facile bioconjugation of gold nanoparticles.

Gold nanoparticles of two different sizes stabilized by a 15-mer peptide ligand specifically designed for this purpose have been prepared in aqueous solution and characterized by UV-vis spectroscopy and TEM. The presence of the ligand and its binding mode to the particles via its four cystein thiols is evidenced by FTIR and NMR spectroscopy. Biotinylation of the particles via binding to a freely accessible lysine residue is demonstrated.