Extra-auricular lesions of proliferative and necrotizing otitis externa in three kittens.

BACKGROUND: Proliferative and necrotising otitis externa (PNOE) is a rare disorder in cats with poorly understood pathogenesis. Extra-auricular (EA) lesions recently have been mentioned in a textbook and in one case report. OBJECTIVES: To describe EA lesions associated with PNOE in three kittens. ANIMALS: A 6-month-old female domestic short hair (DSH) cat (Case 1), an 8-month-old female DSH cat (Case 2) and a 5-month-old female DSH cat (Case 3). METHODS AND RESULTS: All cases exhibited classical lesions of PNOE associated with EA lesions, generalised (cases 1 and 3) or limited to eyelids (Case 2). Lesions were characterised by thick, adherent, hyperkeratotic papules coalescing to plaques and attempts to remove the hyperkeratotic plaques resulted in erosions. Histopathological examinations revealed classical features of PNOE: severe acanthosis associated with a marked lymphocytic exocytosis, satellitosis and apoptotic keratinocytes at all levels of the epidermis and the outer root sheath of hair follicles. Cases 2 and 3 resolved spontaneously. Case 1 remained stable with topical tacrolimus and oral prednisolone after a short course of ciclosporin. CONCLUSIONS AND CLINICAL IMPORTANCE: This report describes EA lesions of PNOE in three kittens. Such lesions may be underdiagnosed, and this report emphasises the role of a thorough clinical inspection in PNOE cases.

Photothermal Control of Heat-Shock Protein Expression at the Single Cell Level.

Laser heating of individual cells in culture recently led to seminal studies in cell poration, fusion, migration, or nanosurgery, although measuring the local temperature increase in such experiments remains a challenge. Here, the laser-induced dynamical control of the heat-shock response is demonstrated at the single cell level, enabled by the use of light-absorbing gold nanoparticles as nanosources of heat and a temperature mapping technique based on quadriwave lateral shearing interferometry (QLSI) measurements. As it is label-free, this approach does not suffer from artifacts inherent to previously reported fluorescence-based temperature-mapping techniques and enables the use of any standard fluorescent labels to monitor in parallel the cell's response.

Single-step homogeneous immunoassay for detecting prostate-specific antigen using dual-color light scattering of metal nanoparticles.

Conventional sandwich-type immunoassays are widely used for protein biomarker detection, yet their workflows are challenged by the need for multiple incubation steps separated by washing cycles. Conducting these immunoassays is thus rather time-consuming and labor-intensive. Moreover, the limited sensitivity around 0.1 ng mL-1 is challenging the monitoring of cancer recurrence, for instance after radical prostatectomy in the case of prostate cancer. Here, we report a single-step homogeneous immunoassay using dual-color light scattering of metal nanoparticles. We detect human free prostate-specific antigen (f-PSA) in a buffered protein matrix solution with a single mixing and incubation step, no washing or purification cycle, and with a total experiment time of less than one hour. The limit of detection is 20 pg mL-1, which is 5× lower as compared to a conventional ELISA kit for f-PSA. The simpler, faster and more sensitive detection of cancer biomarkers opens promising opportunities to improve cancer diagnosis and health monitoring after cancer treatment.

Nanoparticles for bone tissue engineering.

Tissue engineering (TE) envisions the creation of functional substitutes for damaged tissues through integrated solutions, where medical, biological, and engineering principles are combined. Bone regeneration is one of the areas in which designing a model that mimics all tissue properties is still a challenge. The hierarchical structure and high vascularization of bone hampers a TE approach, especially in large bone defects. Nanotechnology can open up a new era for TE, allowing the creation of nanostructures that are comparable in size to those appearing in natural bone. Therefore, nanoengineered systems are now able to more closely mimic the structures observed in naturally occurring systems, and it is also possible to combine several approaches - such as drug delivery and cell labeling - within a single system. This review aims to cover the most recent developments on the use of different nanoparticles for bone TE, with emphasis on their application for scaffolds improvement; drug and gene delivery carriers, and labeling techniques. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:590-611, 2017.

Single-Step DNA Detection Assay Monitoring Dual-Color Light Scattering from Individual Metal Nanoparticle Aggregates.

Efficiently detecting DNA sequences within a limited time is vital for disease screening and public health monitoring. This calls for a new method that combines high sensitivity, fast read-out time, and easy manipulation of the sample, avoiding the extensive steps of DNA amplification, purification, or grafting to a surface. Here, we introduce photon cross-correlation spectroscopy as a new method for specific DNA sensing with high sensitivity in a single-step homogeneous solution phase. Our approach is based on confocal dual-color illumination and detection of the scattering intensities from individual silver nanoparticles and gold nanorods. In the absence of the target DNA, the nanoparticles move independently and their respective scattering signals are uncorrelated. In the presence of the target DNA, the probe-functionalized gold and silver nanoparticles assemble via DNA hybridization with the target, giving rise to temporal coincidence between the signals scattered by each nanoparticle. The degree of coincidence accurately quantifies the amount of target DNA. To demonstrate the efficiency of our technique, we detect a specific DNA sequence of sesame, an allergenic food ingredient, for a range of concentration from 5 pM to 1.5 nM with a limit of detection of 1 pM. Our method is sensitive and specific enough to detect single nucleotide deletion and mismatch. With the dual-color scattering signals being much brighter than fluorescence-based analogs, the analysis is fast, quantitative, and simple to operate, making it valuable for biosensing applications.

Plasmonic response of DNA-assembled gold nanorods: effect of DNA linker length, temperature and linker/nanoparticles ratio.

Optical properties of gold nanorod (AuNR) particles self-assembled with DNA are systematically investigated. The particles assembly is driven by specific base-pair recognition between single strand (ss) DNA linker and DNA anchored to AuNRs, and it results in the distance- and morphology-dependent plasmonic coupling of AuNRs. The longitudinal plasmon band is distinctly affected by tuning the length of DNA linker, the temperature and linker/AuNRs ratio. We observed that the increase of temperature enhances the interparticle interactions and leads to clear distinguishable plasmonic signals between linker lengths up to 100 bases. Both absorbance decrease and shift of the longitudinal plasmon allow for use of AuNR for the DNA sensing applications.

Linear mesostructures in DNA--nanorod self-assembly.

The assembly of molecules and nanoscale objects into one-dimensional (1D) structures, such as fibers, tubules, and ribbons, typically results from anisotropic interactions of the constituents. Conversely, we found that a 1D structure can emerge via a very different mechanism, viz, the spontaneous symmetry breaking of underlying interparticle interactions during structure formation. For systems containing DNA-decorated nanoscale rods, this mechanism, driven by flexible DNA chains, results in the formation of 1D ladderlike mesoscale ribbons with a side-by-side rod arrangement. Detailed structural studies using electron microscopy and in situ small-angle X-ray scattering (SAXS), as well as analysis of assembly kinetics, reveal the role of collective DNA interactions in the formation of the linear structures. Moreover, the reversibility of DNA binding facilitates the development of hierarchical assemblies with time. We also observed similar linear structures of alternating rods and spheres, which implies that the discovered mechanism is generic for nanoscale objects interacting via flexible multiple linkers.

Peptide-grafted nanodiamonds: preparation, cytotoxicity and uptake in cells.

Nanodiamonds that were prepared by high pressure/high temperature were functionalized with biomolecules for biological applications. Nanodiamonds (NDs, < or =35 nm) that were coated by silanization or with polyelectrolyte layers were grafted with a fluorescent thiolated peptide via a maleimido function; this led to an aqueous colloidal suspension that was stable for months. These substituted NDs were not cytotoxic for CHO cells. Their capacity to enter mammalian cells, and their localisation inside were ascertained after labelling the nucleus and actin, by examining the cells by confocal, reflected light and fluorescence microscopy.

Plasmon coupling in layer-by-layer assembled gold nanorod films.

A systematic study of the optical effects derived from plasmon coupling in mono- and multilayers of gold nanorods is presented. The monolayers were prepared using the standard polyelectrolyte-assisted layer-by-layer (LbL) method and gold nanorods coated with either poly(N-vinyl pyrrolidone) or homogeneous silica shells. Such plasmon coupling leads in general to extensive red-shift and broadening of the longitudinal plasmon bands, which are discussed on the basis of recently reported theoretical modeling. Whereas for PVP-coated rods, strong interactions were observed for high-density monolayers and closely spaced multilayers, increasingly efficient screening is observed for thicker silica shells.

Precipitation of Zn2Al LDH by urease enzyme.

A biomineralization process based on the promotion of precipitating agent by the urea-urease enzymatic system is developed to prepare ZnAl layered double hydroxide materials and the effects of the enzymatic reaction parameters on the structural and textural properties of the materials are investigated on the basis of XRD and EM analysis.