Near infra-red luminescent osmium labelled gold nanoparticles for cellular imaging and singlet oxygen generation.

Osmium(II) complexes have attractive properties for potential theranostic agents given their anticancer activitiy, their redox potentials favourable for biological transformations within cancer cells and their luminescence in the near infrared (NIR) region. To achieve localised detection and delivery, gold nanoparticles (AuNP) provide an attractive scaffold to attach multiple luminescent agents on a single particle and provide a multimodal platform for detection and loaclaised delivery. We have developed 13 nm and 25 nm AuNP decorated with an osmium complex based on 1,10-phenantholine and surface active bipyridine ligands, OsPhenSS for live cell imaging and singlet oxygen generation, notated as OsPhenSS·AuNP13 and OsPhenSS·AuNP25.

Luminescence Lifetime-Based Sensing Platform Based on Cyclometalated Iridium(III) Complexes for the Detection of Perfluorooctanoic Acid in Aqueous Samples.

Luminescence lifetimes are an attractive analytical method for detection due to its high sensitivity and stability. Iridium probes exhibit luminescence with long excited-state lifetimes, which are sensitive to the local environment. Perfluorooctanoic acid (PFOA) is listed as a chemical of high concern regarding its toxicity and is classified as a "forever chemical".

Luminescence-Based Infrared Thermal Sensors: Comprehensive Insights.

Recent chronological breakthroughs in materials innovation, their fabrication, and structural designs for disparate applications have paved transformational ways to subversively digitalize infrared (IR) thermal imaging sensors from traditional to smart. The noninvasive IR thermal imaging sensors are at the cutting edge of developments, exploiting the abilities of nanomaterials to acquire arbitrary, targeted, and tunable responses suitable for integration with host materials and devices, intimately disintegrate variegated signals from the target onto depiction without any discomfort, eliminating motional artifacts and collects precise physiological and physiochemical information in natural contexts. Highlighting several typical examples from recent literature, this review article summarizes an accessible, critical, and authoritative summary of an emerging class of advancement in the modalities of nano and micro-scale materials and devices, their fabrication designs and applications in infrared thermal sensors.

Chelating silica nanoparticles for efficient antibiotic delivery and particle imaging in Gram-negative bacteria.

The inefficacy of antibiotics against Gram-negative bacteria is a major challenge for treatment of many clinically important bacterial infections. The complex structure of the double cell membrane of Gram-negative bacteria makes it inaccessible to many key antibiotics such as vancomycin and also presents a major challenge for drug development. In this study we design of a novel hybrid silica nanoparticle system bearing membrane targeting groups with the antibiotic encapsulated together with a ruthenium luminescent tracking agent, for optical detection of the nanoparticle delivery in the bacterial cell.

Photo- and Electrochemical Dual-Responsive Iridium Probe for Saccharide Detection.

Dual detection systems are of interest for rapid, accurate data collection in sensing systems and in vitro testing. We introduce an Ir complex with a boronic acid receptor site attached to the 2-phenylpyridine ligand as an ideal probe with photo- and electrochemical signals that is sensitive to monosaccharide binding in aqueous solution. The complex displays orange luminescence at 618 nm, which is reduced by 70 and 40 % upon binding of fructose and glucose, respectively.

An azido-bridged [FeII4] grid-like molecule showing spin crossover behaviour.

The supramolecular self-assembly synthetic strategy provides a valid tool to obtain polynuclear Fe(II) complexes having effective communication between the metal centres and distinct spin crossover behaviour. Despite the great success in constructing various magnetic molecules, progress has not been made in SCO complexes based on azido bridges. In this article, the coordination-driven supramolecular assembly based on 3,6-substituted pyridazine and azide is presented to afford two Fe(II) grid-like complexes: [(L)FeII4(N)][BPh]·sol (1, L = 3,6-bis(3,5-dimethyl-1-pyrazol-1-yl)pyridazine and 2, L = 3,6-di(pyridin-2-yl)pyridazine).

Alginate-based microparticles coated with HPMCP/AS cellulose-derivatives enable the Ctx(Ile)-Ha antimicrobial peptide application as a feed additive.

Microencapsulation is a potential biotechnological tool, which can overcome antimicrobial peptides (AMP) instabilities and reduce toxic side effects. Thus, this study evaluates the antibacterial activities of the Ctx(Ile)-Ha AMP against multidrug-resistant (MDR) and non-resistant bacteria and develop and characterize peptide-loaded microparticles coated with the enteric polymers hydroxypropylmethylcellulose acetate succinate (HPMCAS) and hydroxypropylmethylcellulose phthalate (HPMCP). Ctx(Ile)-Ha was obtained by solid phase peptide synthesis (SPPS) method, purified and characterized by HPLC and Mass Spectrometry.

Quantification by Luminescence Tracking of Red Emissive Gold Nanoparticles in Cells.

Optical microscopy techniques are ideal for live cell imaging for real-time nanoparticle tracking of nanoparticle localization. However, the quantification of nanoparticle uptake is usually evaluated by analytical methods that require cell isolation. Luminescent labeling of gold nanoparticles with transition metal probes yields particles with attractive photophysical properties, enabling cellular tracking using confocal and time-resolved microscopies.

Strong Coupling and Slow Relaxation of the Magnetization for an Air-Stable [Co] Square with Both Tetrazine Radicals and Azido Bridges.

Introducing both tetrazine radical and azido bridges afforded two air-stable square complexes [M(bpztz)(N)] (M = Zn, ; Co, ; bpztz = 3,6-bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine), where the metal ions are cobridged by μ-azido bridges and tetrazine radicals. Magnetic studies revealed strong antiferromagnetic metal-radical interaction with a coupling constant of -64.7 cm in the 2 formalism in .

Two azido-bridged [2×2] cobalt(ii) grids featuring single-molecule magnet behaviour.

The self-assembly of Co(ii) salts, pyridazine derivatives and azides afforded two azido-bridged [2×2] grid-type complexes {[(L)4CoII4(N3)4][BPh4]4}·sol (1, L = 3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine (pzdz) and sol = 4CH3CN·3CHCl3·2CH3OH and 2, L = 3,6-di(pyridin-2-yl)pyridazine (pydz) and sol = 4CH3CN). Upon comparison with other related grid-like complexes, the incorporation of end-on azido-bridges resulted in overall intramolecular ferromagnetic couplings, and thus endowed complexes 1 and 2 single molecule magnet behaviour with field-induced slow magnetic relaxation.

Assisted delivery of anti-tumour platinum drugs using DNA-coiling gold nanoparticles bearing lumophores and intercalators: towards a new generation of multimodal nanocarriers with enhanced action.

New gold and lipoic based nanocarriers for the delivery of platinum(ii) and platinum(iv) drugs are developed, which allow enhanced loading of the drug on the surface of the nanocarriers and release in a pH-dependent fashion, with superior release at lower pHs which are associated with many tumours. The conjugate nanoparticles and their conjugates enter cells rapidly (within 3 hours). They tend to cluster in vesicles and are also observed by light and electron microscopies in the cytoplasm, endoplasmic reticulum and nucleus.

Cost-Efficient Printing of Graphene Nanostructures on Smart Contact Lenses.

Smart contact lenses have been put forward for years, but there is still no commercial product in the market; the high cost due to expensive fabrication techniques could be one of the reasons. In this paper, first, a cost-efficient and reliable route to fabricate graphene grating on contact lens was designed and demonstrated based on the direct laser interference patterning graphene film on commercial contact lenses using an Nd:YAG laser. The thickness of the film and the interference angle have been taken into consideration.

Imidodiphosphonate Ligands for Enhanced Sensitization and Shielding of Visible and Near-Infrared Lanthanides.

The design of coordination sites around lanthanide ions has a strong impact on the sensitization of their luminescent signal. An imidodiphosphonate anionic binding site is attractive as it can be functionalized with "remote" sensitizer units, such as phenoxy moieties, namely, HtpOp, accompanied by an increased distance of the lanthanide from the ligand high-energy stretching vibrations which quench the luminescence signal, hence providing flexible shielding of the lanthanide. We report the formation and isolation of Ln(tpOp) complexes where Ln = Er, Gd, Tb, Dy, Eu, and Yb and the Y(tpOp) diamagnetic analogue.

Converting Capsules to Sensors for Nondestructive Analysis: From Cargo-Responsive Self-Sensing to Functional Characterization.

A general concept of converting capsules into sensors is reported. Such simple conversion enables instantaneous nondestructive analysis for applications such as controlled release and energy storage among others. Converted capsule sensors are responsive in emission colors to varying core cargos via the incorporation of a solvatochromic fluorophore under excitation.

Iridium Nanoparticles for Multichannel Luminescence Lifetime Imaging, Mapping Localization in Live Cancer Cells.

The development of long-lived luminescent nanoparticles for lifetime imaging is of wide interest as luminescence lifetime is environmentally sensitive detection independent of probe concentration. We report novel iridium-coated gold nanoparticles as probes for multiphoton lifetime imaging with characteristic long luminescent lifetimes based on iridium luminescence in the range of hundreds of nanoseconds and a short signal on the scale of picoseconds based on gold allowing multichannel detection. The tailor-made IrC complex forms stable, water-soluble gold nanoparticles (AuNPs) of 13, 25, and 100 nm, bearing 1400, 3200, and 22 000 IrC complexes per AuNP, respectively.

Tailoring iridium luminescence and gold nanoparticle size for imaging of microvascular blood flow.

Aim: Imaging of blood flow in narrow channels and close to vessel walls is important in cardiovascular research for understanding pathogenesis. Our aim was to provide novel nanoprobes with visible emission and long lifetimes as trackers of flow.

Materials & Methods: Gold nanoparticles coated with an iridium complex were prepared.

Fluorescent Block Copolymer Micelles That Can Self-Report on Their Assembly and Small Molecule Encapsulation.

Block copolymer micelles have been prepared with a dithiomaleimide (DTM) fluorophore located in either the core or shell. Poly(triethylene glycol acrylate)--poly(-butyl acrylate) (P(TEGA)--P(BA)) was synthesized by RAFT polymerization, with a DTM-functional acrylate monomer copolymerized into either the core forming P(BA) block or the shell forming P(TEGA) block. Self-assembly by direct dissolution afforded spherical micelles with of .

Highly luminescent gold nanoparticles: effect of ruthenium distance for nanoprobes with enhanced lifetimes.

The photophysical properties of gold nanoparticles, AuNPs, with sizes of 13, 50 and 100 nm in diameter, coated with surface-active ruthenium complexes have been studied to investigate the effect of the distance of the ruthenium luminescent centre from the gold surface. Luminescence lifetimes of the three ruthenium probes, RuS1, RuS6 and RuS12, with different length spacer units between the surface active groups and the ruthenium centre were taken. The metal complexes were attached to AuNP13, AuNP50 and AuNP100 via thiol groups using a method of precoating the nanoparticles with a fluorinated surfactant.

Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism.

Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear.

The deposition and imaging of silica sub-micron particles in dentine.

Objectives: Sub-micron particles may assist in the delivery of compounds into dentine tubules. The surface interactions of the particles with dentine may prevent them from entering the tubules. The aim of this study is to investigate whether silica particles, treated with surfactants improves dentine tubules occlusion using both artificial and human tooth models

Methods: Spherical silica particles (size 130-810nm) bearing an encapsulated ruthenium luminescent complex were coated with the following surfactants: Zonyl(®) FSA, Triton(®) X-100 and Tween20(®).

Accessible Synthetic Probes for Staining Actin inside Platelets and Megakaryocytes by Employing Lifeact Peptide.

Lifeact is a 17-residue peptide that can be employed in cell microscopy as a probe for F-actin when fused to fluorescent proteins, but therefore is not suitable for all cell types. We have conjugated fluorescently labelled Lifeact to three different cell-penetrating systems (a myristoylated carrier (myr), the pH low insertion peptide (pHLIP) and the cationic peptide TAT) as a strategy to deliver Lifeact into cells and developed new tools for actin staining with improved synthetic accessibility and low toxicity, focusing on their suitability in platelets and megakaryocytes. Using confocal microscopy, we characterised the cell distribution of the new hybrids in fixed cells, and found that both myr- and pHLIP-Lifeact conjugates provide efficient actin staining upon cleavage of Lifeact from the carriers, without affecting cell spreading.

Platelet actin nodules are podosome-like structures dependent on Wiskott-Aldrich syndrome protein and ARP2/3 complex.

The actin nodule is a novel F-actin structure present in platelets during early spreading. However, only limited detail is known regarding nodule organization and function. Here we use electron microscopy, SIM and dSTORM super-resolution, and live-cell TIRF microscopy to characterize the structural organization and signalling pathways associated with nodule formation.