Aerosol Jet Printing of a Benzocyclobutene-Based Ink as Adhesive Material for Wafer Bonding Application

Aerosol jet printing (AJP) is an emerging additive manufacturing technology that is gaining increasing attention in the electronic field. Several studies have been carried out on the AJP of conductive, semiconductive, and dielectric polymers for electronic applications. However, wafer bonding is an application that is still uncovered by literature. Therefore, in this work, the AJP of benzocyclobutene (BCB) as a polymeric adhesive for wafer bonding is presented for the first time. A thorough characterization of the processing parameters is carried out to identify the most ideal conditions for printing at a relatively high speed. Then, square patterns are printed, proving the versatility of the AJP technology in terms of the reachable thickness of the deposited BCB patterns. Complex patterns with a resolution of approximate to 60 mu m are also printed. The bonding properties of the BCB are characterized from a morphological and mechanical point of view. In particular, the shear strength of the BCB coatings deposited with AJP is approximate to 39 MPa and it is comparable with the shear strength of BCB coating deposited by spin-coating. Consequently, AJP represents a valid alternative for the deposition of polymeric adhesive for wafer bonding

Stereoselective Synthesis of α,α’-Dihydroxy-β,β’-diaryl-β-amino Acids by Mannich-like Condensation of Hydroarylamides

Dual \u3b1,\u3b1\u2019-Dihydroxy-\u3b2-amino acids are very interesting tools for several industrial applications. Nevertheless, few derivatives are reported in the literature concerning the substitution pattern as well as their enantioselective syntheses are lacking. Here, we report on the preparation of enantiopure \u3b1,\u3b1\u2019-dihydroxy-\u3b2,\u3b2\u2019-diaryl-\u3b2-amino acid (dual) derivatives by an efficient Mannich-like condensation of hydroarylamides with 5,6-diethoxy-5,6-dimethyl-1,4-dioxan-2-one (triethylsilyl)ketene acetal. The synthetic protocol has been optimized affording the dual compounds in very good yields and with different aryl substitution patterns. Taking advantage of the \u201cdouble stereodifferentiation\u201d concept, a highly stereoselective reaction was performed: of the 16 possible isomers, only two diastereoisomers (d.r. up to 93:7) formed. Insights on the high stereocontrol of this condensation were given

Surface enhanced raman scattering artificial nose for high dimensionality fingerprinting

Label-free surface-enhanced Raman spectroscopy (SERS) can interrogate systems by directly fingerprinting its components’ unique physicochemical properties. In complex biological systems however, this can yield highly overlapping spectra that hinder sample identification. Here, we present an artificial-nose inspired SERS fingerprinting approach where spectral data is obtained as a function of sensor surface chemical functionality. Supported by molecular dynamics modelling, we show that mildly selective self-assembled monolayers can influence the strength and configuration in which analytes interact with plasmonic surfaces, diversifying the resulting SERS fingerprints. Since each sensor generates a modulated signature, the implicit value of increasing the dimensionality of datasets is shown using cell lysates for all possible combinations of up to 9 fingerprints. Reliable improvements in mean discriminatory accuracy towards 100% is achieved with each additional surface functionality. This arrayed label-free platform illustrates the wide-ranging potential of high dimensionality artificial-nose based sensing systems for more reliable assessment of complex biological matrices

Ctr-1 Mets7 motif inspiring new peptide ligands for Cu(i)-catalyzed asymmetric Henry reactions under green conditions

Taking inspiration from the Ctr-1 Mets7 Cu(i) binding motif, effective hybrid catalysts have been developed for asymmetric Henry condensations under green conditions. The introduction of an unnatural dipeptide mimic allowed to increase the catalytic performance. Metal transporters' binding domains could be exploited as a strategy for designing hybrid catalysts for homogeneous catalysis

An Electroactive Oligo-EDOT Platform for Neural Tissue Engineering

The unique electrochemical properties of the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) make it an attractive material for use in neural tissue engineering applications. However, inadequate mechanical properties, and difficulties in processing and lack of biodegradability have hindered progress in this field. Here, the functionality of PEDOT:PSS for neural tissue engineering is improved by incorporating 3,4-ethylenedioxythiophene (EDOT) oligomers, synthesized using a novel end-capping strategy, into block co-polymers. By exploiting end-functionalized oligoEDOT constructs as macroinitiators for the polymerization of poly(caprolactone), a block co-polymer is produced that is electroactive, processable, and bio-compatible. By combining these properties, electroactive fibrous mats are produced for neuronal culture via solution electrospinning and melt electrospinning writing. Importantly, it is also shown that neurite length and branching of neural stem cells can be enhanced on the materials under electrical stimulation, demonstrating the promise of these scaffolds for neural tissue engineering

Stabilization of the Cysteine-Rich Conotoxin MrIA by Using a 1,2,3-Triazole as a Disulfide Bond Mimetic

The design of disulfide bond mimetics is an important strategy for optimising cysteine-rich peptides in drug development. Mimetics of the drug lead conotoxin MrIA, in which one disulfide bond is selectively replaced of by a 1,4-disubstituted-1,2,3-triazole bridge, are described. Sequential copper-catalyzed azide–alkyne cycloaddition (CuAAC; click reaction) followed by disulfide formation resulted in the regioselective syntheses of triazole–disulfide hybrid MrIA analogues. Mimetics with a triazole replacing the Cys4–Cys13 disulfide bond retained tertiary structure and full in vitro and in vivo activity as norepinephrine reuptake inhibitors. Importantly, these mimetics are resistant to reduction in the presence of glutathione, thus resulting in improved plasma stability and increased suitability for drug development.NHMRC 1045964 & 107211

Rational design of a user-friendly aptamer/peptide-based device for the detection of staphylococcus aureus

The urgent need to develop a detection system for Staphylococcus aureus, one of the most common causes of infection, is prompting research towards novel approaches and devices, with a particular focus on point-of-care analysis. Biosensors are promising systems to achieve this aim. We coupled the selectivity and affinity of aptamers, short nucleic acids sequences able to recognize specific epitopes on bacterial surface, immobilized at high density on a nanostructured zirconium dioxide surface, with the rational design of specifically interacting fluorescent peptides to assemble an easy-to-use detection device. We show that the displacement of fluorescent peptides upon the competitive binding of S. aureus to immobilized aptamers can be detected and quantified through fluorescence loss. This approach could be also applied to the detection of other bacterial species once aptamers interacting with specific antigens will be identified, allowing the development of a platform for easy detection of a pathogen without requiring access to a healthcare environment

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum