A novel bio-engineering approach to generate an eminent surfacefunctionalized template for selective detection of female sex pheromone of Helicoverpa armigera

we introduce a novel cost-efficient pheromone sensing based pest detection that uses a microelectromechanical system (MEMS) device15–30 especially designed and functionalized for this purpose. We have developed a MEMS sensor using microcantilevers and fixed-fixed beams as resonant mass sensors for the selective detection of female sex pheromone of Helicoverpa armigera (Hubner), lepidopterous pest of cotton, tomato, rice, pigeonpea and chickpea etc., in air. To the best of our knowledge, this is the first study where silicon dioxide based MEMS devices are covalently functionalized to selectively detect the pheromone molecules for specific insects with sensitivity upto femtogram (fg) level. The successful functionalization of the substrate has been verified by various analytical techniques such as atomic force microscopy (AFM), laser doppler vibrometry (LDV), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The relative sensitivity of these sensors was further improved by different functionalization protocols which increased the number of amine functionalities at each anchor site. The detection limit was observed to be 4.06 ± 0.5 fg of pheromone mass attached to the functionalized cantilevers, which is well below the concentration found for the pheromone at the time of infestation as per the OECD Monograph Guidance – Pheromones and Semiochemicals - September 200231. These MEMS sensors not only eliminate the use of bulky, complex, and fragile instruments, but also reduce the cost considerably for large-scale sensor deployment in real field. Further these pheromone sensors show excellent efficacy and stability in the open atmosphere, even during wet atmospheric conditions like rainy season or in peak summer under bright sunshine. This feature together with the trouble-free transportation aspect of this reversible sensor heightens their potential for the commercial use in any season under ambient conditions. In addition, the chemical functionalizations of the devices have photochemical and thermal stability. The functionalized MEMS devices are also capable of estimating the pheromone concentration present in a field or vineyard and thus may help in determining the level of infestation. The recognition of the pheromone molecules even before visual onset may alert the farmers to take necessary actions in a localized manner before crop loss starts to occur. Hence this approach may be efficiently and economically used in agricultural farms to significantly reduce crop losses and the attendant financial losses.Plant pests exert serious effects on food production due to which the global crop yields are reduced by ~20–40 percent per year. Hence to meet the world’s food needs, loses of food due to crop pests must be reduced. Herein the silicon dioxide based MEMS devices are covalently functionalized for robust and efficient optical sensing of the female sex pheromones of the pests like Helicoverpa armigera for the first time in literature. The functionalized devices are also capable of selectively measuring the concentration of this pheromone at femtogram level which is much below the concentration of pheromone at the time of pest infestation in an agricultural field. Experiments are also performed in a confined region in the presence of male and female pests and tomato plants which directly mimics the real environmental conditions. Again the reversible use and absolutely trouble free transportation of these pheromone nanosensors heightens their potentials for commercial use. Overall, a novel and unique approach for the selective and reversible sensing of female sex pheromones of certain hazardous pests is reported herein which may be efficiently and economically carried forward from the research laboratory to the agricultural field.Indian Institute of Science, Bangalor

A novel bio-engineering approach to generate an eminent surface-functionalized template for selective detection of female sex pheromone of Helicoverpa armigera

Plant pests exert serious effects on food production due to which the global crop yields are reduced by similar to 20-40 percent per year. Hence to meet the world's food needs, loses of food due to crop pests must be reduced. Herein the silicon dioxide based MEMS devices are covalently functionalized for robust and efficient optical sensing of the female sex pheromones of the pests like Helicoverpa armigera for the first time in literature. The functionalized devices are also capable of selectively measuring the concentration of this pheromone at femtogram level which is much below the concentration of pheromone at the time of pest infestation in an agricultural field. Experiments are also performed in a confined region in the presence of male and female pests and tomato plants which directly mimics the real environmental conditions. Again the reversible use and absolutely trouble free transportation of these pheromone nanosensors heightens their potentials for commercial use. Overall, a novel and unique approach for the selective and reversible sensing of female sex pheromones of certain hazardous pests is reported herein which may be efficiently and economically carried forward from the research laboratory to the agricultural field

Efficacious Anticancer Drug Delivery Mediated by a pH-Sensitive Self-Assembly of a Conserved Tripeptide Derived from Tyrosine Kinase NGF Receptor

We present herein a short tripeptide sequence (Lys-Phe-Gly or KFG) that is situated in the juxtamembrane region of the tyrosine kinase nerve growth factor (Trk NGF) receptors. KFG self-assembles in water and shows a reversible and concentration-dependent switching of nanostructures from nanospheres (vesicles) to nanotubes, as evidenced by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The morphology change was associated with a transition in the secondary structure. The tripeptide vesicles have inner aqueous compartments and are stable at pH7.4 but rupture rapidly at pH approximate to 6. The pH-sensitive response of the vesicles was exploited for the delivery of a chemotherapeutic anticancer drug, doxorubicin, which resulted in enhanced cytotoxicity for both drug-sensitive and drug-resistant cells. Efficient intracellular release of the drug was confirmed by fluorescence-activated cell sorting analysis, fluorescence microscopy, and confocal microscopy

Launching electromagnetic donuts: Non-transverse electromagnetic pulses

We demonstrate experimentally for the first time the generation of electromagnetic “Flying Donuts”, few-cycle pulses of toroidal topology with non-separable spatial and temporal structure, and discuss applications in the study of anapole excitations in matter

Concentration Dependent Self-Assembly of TrK-NGF Receptor Derived Tripeptide: New Insights from Experiment and Computer Simulations

Early research has shown that many neurodegenerative diseases are associated with the absence of a short and natural tripeptide sequence, Lys-Phe-Gly (KFG). Herein we report results of both experiments and extensive MD simulations of this tripeptide to understand the self-assembly and morphology as a function of its concentration. Morphologies of the aggregates formed by the tripeptide at low concentration (vesicles), and at high concentration (nanotubes) are studied by several independent 3 μs long Martini coarse-graining MD simulation runs. Further, prediction from MD at still higher concentrations about the formation of rectangular blocks, reported for the first time, has been verified through laboratory experiments. Thus, the computational studies performed are in agreement with the experimental findings observed in our laboratory and a complete control over the formation of various nanostructures is achieved simply by changing the concentration of a short and naturally conserved tripeptide

Calculated CT measured parameters [CTR, PA/A], basic demographic information [age, sex], and patients’ severity information of COVID-19 and healthy subjects.

Calculated CT measured parameters [CTR, PA/A], basic demographic information [age, sex], and patients’ severity information of COVID-19 and healthy subjects.</p

New Water-Soluble Oxyamino Chitosans as Biocampatible Vectors for Efficacious Anticancer Therapy via Co-Delivery of Gene and Drug

Among the many nonviral gene delivery vectors, chitosan, being a polysaccharide of natural origin, has gained special importance. In this report, chitosan (CS) has been solubilized in water by preparing its O-carboxymethyl derivative, CS(CH2COOH), with an optimum degree of carboxymethylation. This has been further derivatized to get the pyridine-substituted product (py)CS(CH2COOH), where the degree of pyridine substitution (47%) was optimized based on zeta potential measurements. The optimized formulation showed a high gene binding ability, forming nanosized positively charged polyelectrolyte complexes with DNA. These polyplexes were stable to DNase and physiological polyanions such as heparin. They also exhibited minimal toxicity in vitro and showed transfection levels comparable to the commercial standard Lipofectamine 2000 and much higher than polyethylenimine (MW, 25 kDa). Additionally, in this study, a hitherto unknown oxyamine derivative of chitosan has been prepared by phthaloyl protection, tosylation, and Gabriel's phthalimide synthesis. Nearly 40% of the primary alcohols were successfully converted to oxyamino functionality, which was used for forming oxime with the anticancer drug doxorubicin. The pH sensitivity of the oxime ether linkage and stability under biologically relevant conditions were then used to establish the compound as a versatile drug delivery vector. Co-delivery of functional gene (p53) and drug (doxorubicin) was accomplished in vitro and in vivo with the chitosan-pyridine imine vector (py)CS(CH2COOH) and the newly synthesized doxorubicin oxime ether CS(Dox). Complete tumor regression with no tumor recurrence and appreciable survivability point to the in vivo effectiveness and biocompatibility of the designed composite formulation. Overall, the pH sensitivity of the oxime linkage aiding slow and steady drug release, together with the sustained gene expression by pyridine-tethered carboxymethyl chitosan, allows us to generate a nanobiocomposite with significantly high anticancer therapeutic potential

A Machine Learning Framework for Detecting COVID-19 Infection Using Surface-Enhanced Raman Scattering

In this study, we explored machine learning approaches for predictive diagnosis using surface-enhanced Raman scattering (SERS), applied to the detection of COVID-19 infection in biological samples. To do this, we utilized SERS data collected from 20 patients at the University of Maryland Baltimore School of Medicine. As a preprocessing step, the positive-negative labels are obtained using Polymerase Chain Reaction (PCR) testing. First, we compared the performance of linear and nonlinear dimensionality techniques for projecting the high-dimensional Raman spectra to a low-dimensional space where a smaller number of variables defines each sample. The appropriate number of reduced features used was obtained by comparing the mean accuracy from a 10-fold cross-validation. Finally, we employed Gaussian process (GP) classification, a probabilistic machine learning approach, to correctly predict the occurrence of a negative or positive sample as a function of the low-dimensional space variables. As opposed to providing rigid class labels, the GP classifier provides a probability (ranging from zero to one) that a given sample is positive or negative. In practice, the proposed framework can be used to provide high-throughput rapid testing, and a follow-up PCR can be used for confirmation in cases where the model\u27s uncertainty is unacceptably high