A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes adv...A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes advantage of the gold nanoparticle tags （AuNPs） conjugated to polyclonal secondary antibodies, which recognize anti-FITC antibodies. The polyclonal nature of the secondary antibodies allows for multiple binding to primary antibodies, leading to enhanced AuNP plasmonics signal. Furthermore, endogenous control consisting of the amplified dog 18S rRNA gene was introduced to avoid false negatives. Using this strategy, 0.038 spiked Leishmania parasites per DNA amplification reaction （1 parasite/100 μL of DNA sample） were detected. Detection limit of LFA was found to be lower than that of the conventional techniques. In summary, our novel LFA design is a universal and simple sensing altemative that can be extended to several other biosensing scenarios.展开更多
Strain engineering provides an effective mean of tuning the fundamental properties of semiconductors for electric and optoelectronic applications. Here we report on how the applied strain changes the emission properti...Strain engineering provides an effective mean of tuning the fundamental properties of semiconductors for electric and optoelectronic applications. Here we report on how the applied strain changes the emission properties of hetero- structures consisting of different crystalline phases in the same CdS nanobelts. The strained portion was found to produce an additional emission peak on the low-energy side that was blueshifted with increasing strain. Furthermore, the additional emission peak obeyed the Varshni equation with temperature and exhibited the band-filling effect at high excitation power. This new emission peak may be attributed to spatially indirect exciton recombination between different crystalline phases of CdS. First-principles calculations were performed based on the spatially indirect exciton recombination, and the calculated and experimental results agreed with one another. Strain proved to be capable of enhancing the anti-Stokes emission, suggesting that the efficiency of laser cooling may be improved by strain engineering.展开更多
The transport properties of artificially engineered superlattices （SLs） can be tailored by incorporating a high density of interfaces in them. Specifically, SiGe SLs with low thermal conductivity values have great p...The transport properties of artificially engineered superlattices （SLs） can be tailored by incorporating a high density of interfaces in them. Specifically, SiGe SLs with low thermal conductivity values have great potential for thermoelectric generation and nano-cooling of Si-based devices. Here, we present a novel approach for customizing thermal transport across nanostructures by fabricating Si/Sil-xGex SLs with well-defined compositional gradients across the SiGe layer from x = 0 to 0.60. We demonstrate that the spatial inhomogeneity of the structure has a remarkable effect on the heat-flow propagation, reducing the thermal conductivity to -2.2 W.m-1.K-1, which is significantly less than the values achieved previously with non-optimized long-period SLs. This approach offers further possibilities for future applications in thermoelectricity.展开更多
A novel, cheap, disposable and single-use nanoparticles-based nanochannel platform assembled on a flexible substrate for label-free immunosensing is pre- sented. This sensing platform is formed by the dip-coating of a...A novel, cheap, disposable and single-use nanoparticles-based nanochannel platform assembled on a flexible substrate for label-free immunosensing is pre- sented. This sensing platform is formed by the dip-coating of a homogeneous and assembled monolayer of carboxylated polystyrene nanospheres （PS, 200 and 500 nm-sized） onto the working area of flexible screen-printed indium tin oxide/polyethylene terephthalate （ITO/PET） electrodes. The spaces between the self-assembled nanospheres generate well-ordered nanochannels, with inter-PS particles distances of around 65 and 24 nm respectively. The formed nanochannels are used for the effective immobilization of antibodies and subsequent protein detection based on the monitoring of [Fe（CN）6]^4- flow through diffusion and the decrease in the differential pulse voltammetric signal upon immunocomplex formation. The obtained sensing system is nanochannel-size dependent and allows human immunoglobulin G （IgG） （chosen as a model analyte） to be detected at levels of 580 ng/mL. The system also exhibits an excellent specificity against other proteins present in real samples and shows good performance with a human urine sample. The developed device represents an integrated and simple biodetection system which overcomes many of the limitations of previously reported nanochannels-based approaches and can be extended in the future to several other immuno and DNA detection systems.展开更多
文摘A novel triple lines lateral-flow assay （LFA） with enhanced sensitivity for the detection of Leishmania infantum DNA in dog blood samples was designed and successfully applied. The enhanced LFA methodology takes advantage of the gold nanoparticle tags （AuNPs） conjugated to polyclonal secondary antibodies, which recognize anti-FITC antibodies. The polyclonal nature of the secondary antibodies allows for multiple binding to primary antibodies, leading to enhanced AuNP plasmonics signal. Furthermore, endogenous control consisting of the amplified dog 18S rRNA gene was introduced to avoid false negatives. Using this strategy, 0.038 spiked Leishmania parasites per DNA amplification reaction （1 parasite/100 μL of DNA sample） were detected. Detection limit of LFA was found to be lower than that of the conventional techniques. In summary, our novel LFA design is a universal and simple sensing altemative that can be extended to several other biosensing scenarios.
文摘Strain engineering provides an effective mean of tuning the fundamental properties of semiconductors for electric and optoelectronic applications. Here we report on how the applied strain changes the emission properties of hetero- structures consisting of different crystalline phases in the same CdS nanobelts. The strained portion was found to produce an additional emission peak on the low-energy side that was blueshifted with increasing strain. Furthermore, the additional emission peak obeyed the Varshni equation with temperature and exhibited the band-filling effect at high excitation power. This new emission peak may be attributed to spatially indirect exciton recombination between different crystalline phases of CdS. First-principles calculations were performed based on the spatially indirect exciton recombination, and the calculated and experimental results agreed with one another. Strain proved to be capable of enhancing the anti-Stokes emission, suggesting that the efficiency of laser cooling may be improved by strain engineering.
文摘The transport properties of artificially engineered superlattices （SLs） can be tailored by incorporating a high density of interfaces in them. Specifically, SiGe SLs with low thermal conductivity values have great potential for thermoelectric generation and nano-cooling of Si-based devices. Here, we present a novel approach for customizing thermal transport across nanostructures by fabricating Si/Sil-xGex SLs with well-defined compositional gradients across the SiGe layer from x = 0 to 0.60. We demonstrate that the spatial inhomogeneity of the structure has a remarkable effect on the heat-flow propagation, reducing the thermal conductivity to -2.2 W.m-1.K-1, which is significantly less than the values achieved previously with non-optimized long-period SLs. This approach offers further possibilities for future applications in thermoelectricity.
文摘A novel, cheap, disposable and single-use nanoparticles-based nanochannel platform assembled on a flexible substrate for label-free immunosensing is pre- sented. This sensing platform is formed by the dip-coating of a homogeneous and assembled monolayer of carboxylated polystyrene nanospheres （PS, 200 and 500 nm-sized） onto the working area of flexible screen-printed indium tin oxide/polyethylene terephthalate （ITO/PET） electrodes. The spaces between the self-assembled nanospheres generate well-ordered nanochannels, with inter-PS particles distances of around 65 and 24 nm respectively. The formed nanochannels are used for the effective immobilization of antibodies and subsequent protein detection based on the monitoring of [Fe（CN）6]^4- flow through diffusion and the decrease in the differential pulse voltammetric signal upon immunocomplex formation. The obtained sensing system is nanochannel-size dependent and allows human immunoglobulin G （IgG） （chosen as a model analyte） to be detected at levels of 580 ng/mL. The system also exhibits an excellent specificity against other proteins present in real samples and shows good performance with a human urine sample. The developed device represents an integrated and simple biodetection system which overcomes many of the limitations of previously reported nanochannels-based approaches and can be extended in the future to several other immuno and DNA detection systems.
