Viable stretchable plasmonics based on unidirectional nanoprisms

Well-defined ordered arrays of plasmonic nanostructures were fabricated on stretchable substrates and tunable plasmon-coupling-based sensing properties were comprehensively demonstrated upon extension and contraction. Regular nanoprism patterns consisting of Ag, Au and Ag/Au bilayers were constructed on the stretchable polydimethylsiloxane substrate. The nanoprisms had the same orientation over the entire substrate (3 x 3 cm(2)) via metal deposition on a single-crystal microparticle monolayer assembly. The plasmonic sensor based on the Ag/Au bilayer showed a 6-fold enhanced surface enhanced Raman scattering signal under 20% uniaxial extension, whereas a 3-fold increase was observed upon 6% contraction, compared with the Au nanoprism arrays. The sensory behaviors were corroborated by finite-difference time-domain simulation, demonstrating the tunable electromagnetic field enhancement effect via the localized surface plasmon resonance coupling. The advanced flexible plasmonic-coupling-based devices with tunable and quantifiable performance herein suggested are expected to unlock promising potential in practical bio-sensing, biotechnological applications and optical devices.11Ysciescopu

Direct deposition of anatase TiO2 on thermally unstable gold nanobipyramid: Morphology-conserved plasmonic nanohybrid for combinational photothermal and photocatalytic cancer therapy

Deposition of crystalline titanium dioxide (TiO2) on gold nanostructures has been considered as a promising strategy for near-infrared (NIR) light-activated photocatalysis. A typical route comprises pre-deposition of amorphous TiO2 on the gold surface and its ensuing crystallization by high-temperature annealing. Such condition, however, is not compatible with highly plasmonic but thermally unstable sharp-tipped gold nanostructures, causing structural disruption and plasmonic decline. Herein, we report a hybridization method excluding high-temperature annealing, i.e., direct deposition of anatase TiO2 onto sharp-tipped gold nanobipyramid (Au NBP/a-TiO2) with conserving their morphology without agglomeration via low-temperature hydrothermal reaction. In addition to keeping the plasmonic photothermal performance, Au NBP/a-TiO2 exhibits enhanced photocatalytic generation of reactive oxygen species in response to the NIR excitation, evidencing the efficient injection of hot electrons from the Au NBP to the anatase shell. In vitro and in vivo studies revealed that the efficient photocatalytic/photothermal responses of Au NBP/a-TiO2, along with dispersion stability in biological media and minimal toxicity, hold potential for synergistic photothermal and photodynamic therapy. We believe that the low-temperature synthetic method introduced here might offer a general way of crystalline deposition of TiO2 on a variety of gold nanostructures, broadening the spectrum of NIR-responsive photocatalytic hybrid nanostructures for biomedical applications

Towards engineering heart tissues from bioprinted cardiac spheroids.

Currentin vivoandin vitromodels fail to accurately recapitulate the human heart microenvironment for biomedical applications. This study explores the use of cardiac spheroids (CSs) to biofabricate advancedin vitromodels of the human heart. CSs were created from human cardiac myocytes, fibroblasts and endothelial cells (ECs), mixed within optimal alginate/gelatin hydrogels and then bioprinted on a microelectrode plate for drug testing. Bioprinted CSs maintained their structure and viability for at least 30 d after printing. Vascular endothelial growth factor (VEGF) promoted EC branching from CSs within hydrogels. Alginate/gelatin-based hydrogels enabled spheroids fusion, which was further facilitated by addition of VEGF. Bioprinted CSs contracted spontaneously and under stimulation, allowing to record contractile and electrical signals on the microelectrode plates for industrial applications. Taken together, our findings indicate that bioprinted CSs can be used to biofabricate human heart tissues for long termin vitrotesting. This has the potential to be used to study biochemical, physiological and pharmacological features of human heart tissue

Formation of Toxic Oligomeric α-Synuclein Species in Living Cells

Background: Misfolding, oligomerization, and fibrillization of α-synuclein are thought to be central events in the onset and progression of Parkinson's disease (PD) and related disorders. Although fibrillar α-synuclein is a major component of Lewy bodies (LBs), recent data implicate prefibrillar, oligomeric intermediates as the toxic species. However, to date, oligomeric species have not been identified in living cells. Methodology/Principal Findings: Here we used bimolecular fluorescence complementation (BiFC) to directly visualize α-synuclein oligomerization in living cells, allowing us to study the initial events leading to α-synuclein oligomerization, the precursor to aggregate formation. This novel assay provides us with a tool with which to investigate how manipulations affecting α-synuclein aggregation affect the process over time. Stabilization of α-synuclein oligomers via BiFC results in increased cytotoxicity, which can be rescued by Hsp70 in a process that reduces the formation of α-synuclein oligomers. Introduction of PD-associated mutations in α-synuclein did not affect oligomer formation but the biochemical properties of the mutant α-synuclein oligomers differ from those of wild type α-synuclein. Conclusions/Significance: This novel application of the BiFC assay to the study of the molecular basis of neurodegenerative disorders enabled the direct visualization of α-synuclein oligomeric species in living cells and its modulation by Hsp70, constituting a novel important tool in the search for therapeutics for synucleinopathies

Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

Long-chain polyunsaturated fatty acids (LC-PUFAs) such as arachidonic (ARA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids are essential components of biomembranes, particularly in neural tissues. Endogenous synthesis of ARA, EPA and DHA occurs from precursor dietary essential fatty acids such as linoleic and α-linolenic acid through elongation and Δ5 and Δ6 desaturations. With respect to desaturation activities some noteworthy differences have been noted in vertebrate classes. In mammals, the Δ5 activity is allocated to the Fads1 gene, while Fads2 is a Δ6 desaturase. In contrast, teleosts show distinct combinations of desaturase activities (e.g. bifunctional or separate Δ5 and Δ6 desaturases) apparently allocated to Fads2-type genes. To determine the timing of Fads1-Δ5 and Fads2-Δ6 evolution in vertebrates we used a combination of comparative and functional genomics with the analysis of key phylogenetic species. Our data show that Fads1 and Fads2 genes with Δ5 and Δ6 activities respectively, evolved before gnathostome radiation, since the catshark Scyliorhinus canicula has functional orthologues of both gene families. Consequently, the loss of Fads1 in teleosts is a secondary episode, while the existence of Δ5 activities in the same group most likely occurred through independent mutations into Fads2 type genes. Unexpectedly, we also establish that events of Fads1 gene expansion have taken place in birds and reptiles. Finally, a fourth Fads gene (Fads4) was found with an exclusive occurrence in mammalian genomes. Our findings enlighten the history of a crucially important gene family in vertebrate fatty acid metabolism and physiology and provide an explanation of how observed lineage-specific gene duplications, losses and diversifications might be linked to habitat-specific food web structures in different environments and over geological timescales

Characterization techniques for studying the properties of nanocarriers for systemic delivery

Nanocarriers have attracted a huge interest in the last decade as efficient drug delivery systems and diagnostic tools. They enable effective, targeted, controlled delivery of therapeutic molecules while lowering the side effects caused during the treatment. The physicochemical properties of nanoparticles determine their in vivo pharmacokinetics, biodistribution and tolerability. The most analyzed among these physicochemical properties are shape, size, surface charge and porosity and several techniques have been used to characterize these specific properties. These different techniques assess the particles under varying conditions, such as physical state, solvents etc. and as such probe, in addition to the particles themselves, artifacts due to sample preparation or environment during measurement. Here, we discuss the different methods to precisely evaluate these properties, including their advantages or disadvantages. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed

How might infant and paediatric immune responses influence malaria vaccine efficacy?

Naturally acquired immunity to malaria requires repeat infections yet does not engender sterile immunity or long-lasting protective immunologic memory. This renders infants and young children the most susceptible to malaria-induced morbidity and mortality, and the ultimate target for a malaria vaccine. The prevailing paradigm is that infants initially garner protection due to transplacentally transferred anti-malarial antibodies and other intrinsic factors such as foetal haemoglobin. As these wane infants have an insufficient immune repertoire to prevent genetically diverse Plasmodium infections and an inability to control malaria-induced immunopathology. This Review discusses humoral, cell-mediated and innate immune responses to malaria and how each contributes to protection – focusing on how deficiencies in infant and paediatric immune responses might influence malaria vaccine efficacy in this population. In addition, burgeoning evidence suggests a role for inhibitory receptors that limit immunopathology and guide the development of long-lived immunity. Precisely how age or malaria infections influence the function of these regulators is unknown. Therefore the possibility that infants may not have the immune-dexterity to balance effective parasite clearance with timely immune-regulation leading to protective immunologic memory is considered. And thus, malaria vaccines tested in adults and older children may not be predictive for trials conducted in infants

The IPIN 2019 Indoor Localisation Competition—Description and Results

IPIN 2019 Competition, sixth in a series of IPIN competitions, was held at the CNR Research Area of Pisa (IT), integrated into the program of the IPIN 2019 Conference. It included two on-site real-time Tracks and three off-site Tracks. The four Tracks presented in this paper were set in the same environment, made of two buildings close together for a total usable area of 1000 m 2 outdoors and and 6000 m 2 indoors over three floors, with a total path length exceeding 500 m. IPIN competitions, based on the EvAAL framework, have aimed at comparing the accuracy performance of personal positioning systems in fair and realistic conditions: past editions of the competition were carried in big conference settings, university campuses and a shopping mall. Positioning accuracy is computed while the person carrying the system under test walks at normal walking speed, uses lifts and goes up and down stairs or briefly stops at given points. Results presented here are a showcase of state-of-the-art systems tested side by side in real-world settings as part of the on-site real-time competition Tracks. Results for off-site Tracks allow a detailed and reproducible comparison of the most recent positioning and tracking algorithms in the same environment as the on-site Tracks

Sponge spicules as blueprints for the biofabrication of inorganic–organic composites and biomaterials

While most forms of multicellular life have developed a calcium-based skeleton, a few specialized organisms complement their body plan with silica. However, of all recent animals, only sponges (phylum Porifera) are able to polymerize silica enzymatically mediated in order to generate massive siliceous skeletal elements (spicules) during a unique reaction, at ambient temperature and pressure. During this biomineralization process (i.e., biosilicification) hydrated, amorphous silica is deposited within highly specialized sponge cells, ultimately resulting in structures that range in size from micrometers to meters. Spicules lend structural stability to the sponge body, deter predators, and transmit light similar to optic fibers. This peculiar phenomenon has been comprehensively studied in recent years and in several approaches, the molecular background was explored to create tools that might be employed for novel bioinspired biotechnological and biomedical applications. Thus, it was discovered that spiculogenesis is mediated by the enzyme silicatein and starts intracellularly. The resulting silica nanoparticles fuse and subsequently form concentric lamellar layers around a central protein filament, consisting of silicatein and the scaffold protein silintaphin-1. Once the growing spicule is extruded into the extracellular space, it obtains final size and shape. Again, this process is mediated by silicatein and silintaphin-1, in combination with other molecules such as galectin and collagen. The molecular toolbox generated so far allows the fabrication of novel micro- and nanostructured composites, contributing to the economical and sustainable synthesis of biomaterials with unique characteristics. In this context, first bioinspired approaches implement recombinant silicatein and silintaphin-1 for applications in the field of biomedicine (biosilica-mediated regeneration of tooth and bone defects) or micro-optics (in vitro synthesis of light waveguides) with promising results