23 research outputs found

    Evaluation of Drought Resistance Criteria in Some Cumin (Cuminum cyminum L.) Landraces

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    Cumin is one of the most important herbal drug crops of Iran and used in traditional foods. It needs low water for growth cycle, and grows in arid and semi-arid regions of Iran. For evaluation of drought resistance of some cumin landraces of Iran, two experiments as under drought stress and normal condition were conducted. The parameters of leaf water potential, osmotic potential, harvest index and stress susceptibility index (SSI) were studied on cumin landraces. Sarvestan-e Fars, Tabriz and Sabzevar landraces were distinguished as arought tolerant landraces. Cluster analysis using single linkage method, classified the genotypes into three groups. Sabzevar, Sarvestan-e Fars, Tabriz and Khorasan2-374 landraces made the first group, Zirkoh-e Quen, Qunabad and Ferdous landraces, included in the second group, and  Kerman landrace, alone, was located in the third group

    Real-time wash-free detection of unlabeled PNA-DNA hybridization using discrete FET sensor

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    Abstract We demonstrate an electrochemical sensor for detection of unlabeled single-stranded DNA using peptide nucleic acid (PNA) probes coupled to the field-effect transistor (FET) gate. The label-free detection relies on the intrinsic charge of the DNA backbone. Similar detection schemes have mainly concentrated on sensitivity improvement with an emphasis on new sensor structures. Our approach focuses on using an extended-gate that separates the FET and the sensing electrode yielding a simple and mass fabricable device. We used PNA probes for efficient hybridization in low salt conditions that is required to avoid the counter ion screening. As a result, significant part of the target DNA lies within the screening length of the sensor. With this, we achieved a wash-free detection where  typical gate potential shifts are more than 70 mV with 1 µM target DNA. We routinely obtained a real-time, label- and wash-free specific detection of target DNA in nanomolar concentration with low-cost electronics and the responses were achieved within minutes after introducing targets to the solution. Furthermore, the results suggest that the sensor performance is limited by specificity rather than by sensitivity and using low-cost electronics does not limit the sensor performance in the presented sensor configuration

    Semiconductor Electronic Label-Free Assay for Predictive Toxicology

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    While animal experimentations have spearheaded numerous breakthroughs in biomedicine, they also have spawned many logistical concerns in providing toxicity screening for copious new materials. Their prioritization is premised on performing cellular-level screening in vitro. Among the screening assays, secretomic assay with high sensitivity, analytical throughput, and simplicity is of prime importance. Here, we build on the over 3-decade-long progress on transistor biosensing and develop the holistic assay platform and procedure called semiconductor electronic label-free assay (SELFA). We demonstrate that SELFA, which incorporates an amplifying nanowire field-effect transistor biosensor, is able to offer superior sensitivity, similar selectivity, and shorter turnaround time compared to standard enzyme-linked immunosorbent assay (ELISA). We deploy SELFA secretomics to predict the inflammatory potential of eleven engineered nanomaterials in vitro, and validate the results with confocal microscopy in vitro and confirmatory animal experiment in vivo. This work provides a foundation for high-sensitivity label-free assay utility in predictive toxicology
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