Nanometer-sized liposomes decorated with macromolecules are increasingly used as drug delivery vehicles due to their long lifetimes and target cell specificity, but surface characterization methods often change their properties, which leads to incorrect results. Ligand binding is commonly applied for characterizing these surface modifications. Here, we use a nanofluidic-based label-free sensor for real-time sensing of ligands binding to liposomes. The liposomes are trapped in a nanochannel with a salt concentration gradient, and as the trapping position depends on the liposomes' zeta potential, it changes when charged ligands bind to the liposomes. Our sensing method does not require immobilization of the liposomes or labeling of the ligands with fluorophores, which may both affect the sensing. https://www.selleckchem.com/products/disodium-phosphate.html The zeta potential sensing is demonstrated by measuring hybridization of DNA targets with complementary DNA probes on liposome surfaces. DNA hybridization is monitored for both ensembles and individual liposomes, the latter allows for analysis of ensemble heterogeneity, and we demonstrate sensitivity to changes in surface charge down to 1.5%. DNA hybridization is used to demonstrate label-free sensing, but the method also has potential applications within exosome characterization, where biorecognition of, e.g., surface DNA, proteins, and antibodies is a promising candidate for early stage cancer diagnostics.Atomic-scale incorporation of CuAlSe2 inclusions within the Cu2Se matrix, achieved through a solid-state transformation of CuSe2 template precursor using elemental Cu and Al, enables a unique temperature-dependent dynamic doping of the Cu2Se matrix. The CuAlSe2 inclusions, due to their ability to accommodate a large fraction of excess metal atoms within their crystal lattice, serve as a "reservoir" for Cu ions diffusing away from the Cu2Se matrix. Such unidirectional diffusion of Cu ions from the Cu2Se matrix to the CuAlSe2 inclusion leads to the formation, near the CuAlSe2/Cu2Se interface, of a high density of Cu-deficient β-Cu2-δSe nanoparticles within the α-Cu2Se matrix and the formation of Cu-rich Cu1+yAlSe2 nanoparticles with the CuAlSe2 inclusions. This gives rise to a large enhancement in carrier concentration and electrical conductivity at elevated temperatures. Furthermore, the nanostructuring near the CuAlSe2/Cu2Se interface, as well as the extensive atomic disorder in the Cu2Se and CuAlSe2 phases, significantly increases phonon scattering, leading to suppressed lattice thermal conductivity. Consequently, a significant improvement in ZT is observed for selected Cu2Se/CuAlSe2 composites. This work demonstrates the use of in situ-formed interactive secondary phases in a semiconducting matrix as an elegant alternative approach for further improvement of the performance of leading thermoelectric materials.Dual-cross-linked network (DCN) hydrogels with multiresponsive and self-healing properties are attracting intensive interests due to their enhanced mechanical strength for a wide range of applications. Herein, we developed a DCN hydrogel that combines a dynamic imine and a benzoxaboronic ester with a neutral pKa value (∼7.2) as dual linkages and contains biocompatible zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] as the backbone. Oscillatory rheology result indicated shear strengthening mechanical properties compared to the single-cross-linked network (SCN) hydrogels, which use either imine bond or benzoxaboronic ester as the linkage alone. Due to the coexistence of stimuli-responsive imine and benzoxaboronic ester, the DCN hydrogels show sensitive multiple responsiveness to pH, sugar, and hydrogen peroxide. The dynamic nature of the dual linkages endows the DCN hydrogels with excellent self-healing ability after fracture. More importantly, the excellent biocompatibility and performance in three-dimensional (3D) cell encapsulation were established by a cytotoxicity Live/Dead assay, indicating DCN hydrogel's great potential as a cell culture scaffold. The biocompatible poly(MPC)-based backbone and the rapid formation of the cross-linking network make the DCN hydrogels promising candidates for future biomedical applications.Transition metal dichalcogenide (TMD) materials have emerged as promising candidates for thin-film solar cells due to their wide bandgap range across the visible wavelengths, high absorption coefficient, and ease of integration with both arbitrary substrates and conventional semiconductor technologies. However, reported TMD-based solar cells suffer from relatively low external quantum efficiencies (EQE) and low open circuit voltage due to unoptimized design and device fabrication. This paper studies Pt/WSe2 vertical Schottky junction solar cells with various WSe2 thicknesses in order to find the optimum absorber thickness. Also, we show that the devices' photovoltaic performance can be improved via Al2O3 passivation, which increases the EQE up to 29.5% at 410 nm wavelength incident light. The overall resulting short circuit current improves through antireflection coating, surface doping, and surface trap passivation effects. Thanks to the Al2O3 coating, this work demonstrates a device with an open circuit voltage (VOC) of 380 mV and a short circuit current density (JSC) of 10.7 mA/cm2. Finally, the impact of Schottky barrier height inhomogeneity at the Pt/WSe2 contact is investigated as a source of open circuit voltage lowering in these devices.Vibrational circular dichroism (VCD) spectroscopy has emerged as a powerful platform to quantify chirality, a vital biological property that performs a pivotal role in the metabolism of life organisms. With a photoelastic modulator (PEM) integrated into an infrared spectrometer, the differential response of a sample to the direction of circularly polarized light can be used to infer conformation handedness. However, these optical components inherently exhibit chromatic behavior and are typically optimized at discrete spectral frequencies. Advancements of discrete frequency infrared (DFIR) spectroscopic microscopes in spectral image quality and data throughput are promising for use toward analytical VCD measurements. Utilizing the PEM advantages incorporated into a custom-built QCL microscope, we demonstrate a point scanning VCD instrument capable of acquiring spectra rapidly across all fingerprint region wavelengths in transmission configuration. Moreover, for the first time, we also demonstrate the VCD imaging performance of our instrument for site-specific chirality mapping of biological tissue samples.
Nanometer-sized liposomes decorated with macromolecules are increasingly used as drug delivery vehicles due to their long lifetimes and target cell specificity, but surface characterization methods often change their properties, which leads to incorrect results. Ligand binding is commonly applied for characterizing these surface modifications. Here, we use a nanofluidic-based label-free sensor for real-time sensing of ligands binding to liposomes. The liposomes are trapped in a nanochannel with a salt concentration gradient, and as the trapping position depends on the liposomes' zeta potential, it changes when charged ligands bind to the liposomes. Our sensing method does not require immobilization of the liposomes or labeling of the ligands with fluorophores, which may both affect the sensing. https://www.selleckchem.com/products/disodium-phosphate.html The zeta potential sensing is demonstrated by measuring hybridization of DNA targets with complementary DNA probes on liposome surfaces. DNA hybridization is monitored for both ensembles and individual liposomes, the latter allows for analysis of ensemble heterogeneity, and we demonstrate sensitivity to changes in surface charge down to 1.5%. DNA hybridization is used to demonstrate label-free sensing, but the method also has potential applications within exosome characterization, where biorecognition of, e.g., surface DNA, proteins, and antibodies is a promising candidate for early stage cancer diagnostics.Atomic-scale incorporation of CuAlSe2 inclusions within the Cu2Se matrix, achieved through a solid-state transformation of CuSe2 template precursor using elemental Cu and Al, enables a unique temperature-dependent dynamic doping of the Cu2Se matrix. The CuAlSe2 inclusions, due to their ability to accommodate a large fraction of excess metal atoms within their crystal lattice, serve as a "reservoir" for Cu ions diffusing away from the Cu2Se matrix. Such unidirectional diffusion of Cu ions from the Cu2Se matrix to the CuAlSe2 inclusion leads to the formation, near the CuAlSe2/Cu2Se interface, of a high density of Cu-deficient β-Cu2-δSe nanoparticles within the α-Cu2Se matrix and the formation of Cu-rich Cu1+yAlSe2 nanoparticles with the CuAlSe2 inclusions. This gives rise to a large enhancement in carrier concentration and electrical conductivity at elevated temperatures. Furthermore, the nanostructuring near the CuAlSe2/Cu2Se interface, as well as the extensive atomic disorder in the Cu2Se and CuAlSe2 phases, significantly increases phonon scattering, leading to suppressed lattice thermal conductivity. Consequently, a significant improvement in ZT is observed for selected Cu2Se/CuAlSe2 composites. This work demonstrates the use of in situ-formed interactive secondary phases in a semiconducting matrix as an elegant alternative approach for further improvement of the performance of leading thermoelectric materials.Dual-cross-linked network (DCN) hydrogels with multiresponsive and self-healing properties are attracting intensive interests due to their enhanced mechanical strength for a wide range of applications. Herein, we developed a DCN hydrogel that combines a dynamic imine and a benzoxaboronic ester with a neutral pKa value (∼7.2) as dual linkages and contains biocompatible zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)] as the backbone. Oscillatory rheology result indicated shear strengthening mechanical properties compared to the single-cross-linked network (SCN) hydrogels, which use either imine bond or benzoxaboronic ester as the linkage alone. Due to the coexistence of stimuli-responsive imine and benzoxaboronic ester, the DCN hydrogels show sensitive multiple responsiveness to pH, sugar, and hydrogen peroxide. The dynamic nature of the dual linkages endows the DCN hydrogels with excellent self-healing ability after fracture. More importantly, the excellent biocompatibility and performance in three-dimensional (3D) cell encapsulation were established by a cytotoxicity Live/Dead assay, indicating DCN hydrogel's great potential as a cell culture scaffold. The biocompatible poly(MPC)-based backbone and the rapid formation of the cross-linking network make the DCN hydrogels promising candidates for future biomedical applications.Transition metal dichalcogenide (TMD) materials have emerged as promising candidates for thin-film solar cells due to their wide bandgap range across the visible wavelengths, high absorption coefficient, and ease of integration with both arbitrary substrates and conventional semiconductor technologies. However, reported TMD-based solar cells suffer from relatively low external quantum efficiencies (EQE) and low open circuit voltage due to unoptimized design and device fabrication. This paper studies Pt/WSe2 vertical Schottky junction solar cells with various WSe2 thicknesses in order to find the optimum absorber thickness. Also, we show that the devices' photovoltaic performance can be improved via Al2O3 passivation, which increases the EQE up to 29.5% at 410 nm wavelength incident light. The overall resulting short circuit current improves through antireflection coating, surface doping, and surface trap passivation effects. Thanks to the Al2O3 coating, this work demonstrates a device with an open circuit voltage (VOC) of 380 mV and a short circuit current density (JSC) of 10.7 mA/cm2. Finally, the impact of Schottky barrier height inhomogeneity at the Pt/WSe2 contact is investigated as a source of open circuit voltage lowering in these devices.Vibrational circular dichroism (VCD) spectroscopy has emerged as a powerful platform to quantify chirality, a vital biological property that performs a pivotal role in the metabolism of life organisms. With a photoelastic modulator (PEM) integrated into an infrared spectrometer, the differential response of a sample to the direction of circularly polarized light can be used to infer conformation handedness. However, these optical components inherently exhibit chromatic behavior and are typically optimized at discrete spectral frequencies. Advancements of discrete frequency infrared (DFIR) spectroscopic microscopes in spectral image quality and data throughput are promising for use toward analytical VCD measurements. Utilizing the PEM advantages incorporated into a custom-built QCL microscope, we demonstrate a point scanning VCD instrument capable of acquiring spectra rapidly across all fingerprint region wavelengths in transmission configuration. Moreover, for the first time, we also demonstrate the VCD imaging performance of our instrument for site-specific chirality mapping of biological tissue samples.
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