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We demonstrate the acoustic charge transport of optically induced excitons in two organic semiconductors, P3HT and MEH-PPV, up to a distance of 3 mm. The device consists of a surface acoustic wave (SAW) resonator transmitting SAW through a polymer layer where acoustic charge transport takes place and a polymer diode at the end to collect the charges. The voltage excitation is provided using an interdigital transducer (IDT) on a piezoelectric YZ lithium niobate substrate producing Rayleigh SAW at 42 MHz. Optical illumination up to 15 mW/cm2 intensity is applied to induce excitons in the polymer layer deposited on the lithium niobate substrate. The photogenerated excitons in the polymer are ionized by SAW field resulting in free carriers that are transported to the polymer diode by the travelling SAW. A surge in photovoltaic current in the diode is observed in the presence of SAW when the carriers are optically generated away from the diode. The maximum charge capacity and transfer efficiency of the acoustic transport are calculated for various SAW power and illumination intensities. A theoretical analysis of charge carrier dynamics in the presence of a moving SAW field is also performed using a semi-classical Hamiltonian of the system.

RNA has attracted recent attention for its key role in gene expression and targeting by small molecules for therapeutic intervention. This work focuses towards understanding interaction of harmalol, a DNA intercalator, with RNAs of different motifs viz. single-stranded A-form poly(A), double-stranded A-form of poly(C)·poly(G), and clover leaf tRNA by different spectroscopic, calorimetric, and molecular modeling techniques. Results of this study converge to suggest that (i) binding constant varied in the order poly(C)·poly(G) > tRNA > poly(A), (ii) non-cooperative binding of harmalol to poly(C)·poly(G) and poly(A) and cooperative binding with tRNA, (iii) significant structural changes of poly(C)·poly(G) and tRNA with concomitant induction of optical activity in the bound achiral alkaloid molecules, while with poly(A) no induced Circular dichroism (CD) perturbation was observed, (iv) the binding was predominantly exothermic, enthalpy-driven, entropy-favored with poly(C)·poly(G), while it was entropy driven with tRNA and poly(A), (v) a hydrophobic contribution and comparatively large role of non polyelectrolytic forces to Gibbs energy changes with poly(C)·poly(G) and tRNA and (vi) intercalated state of harmalol inside poly(C)·poly(G) structure as revealed from molecular docking was supported by the viscometric and ferrocyanide quenching data. All these findings unequivocally pointed out that harmalol prefers binding with poly(C)·poly(G), compared to tRNA and poly(A); this results serve as data for the development of RNA-based antiviral drugs.

Background: Diethylnitrosamine (DEN) promoted by carbon tetrachloride (CCl 4) forms DNA adducts inducing hepatocellular carcinoma (HCC). Plant alkaloid, harmalol, is being used as a therapeutic agent against HCC due to its accessibility and efficacy by apoptosis and inhibiting proliferation of cancer epithelial cells. Result: Seven groups of Swiss albino mice were taken. Different stages of liver tissues and serum from various experimental groups were collected before and after harmalol treatment. The investigation was carried out by enzyme assay, bilirubin level in the blood, DNA, RNA, normal serum protein of liver tissue, and alpha-feto protein estimation of serum. Gross morphological assessment of liver, histological, and different apoptosis markers viz. p53, caspase3, and cytochrome C expression were analyzed by RT-PCR and Western blot. Harmalol (10 mg/kg B.W. per week, I.P.) for 9 weeks showed a significant reduction in hepatocellular foci, nodules, and carcinoma ultimately retaining the normal morphology. It further induces ROS-dependent apoptosis through mitochondrial cytochrome C release that induces p53 by caspase3 activation. Conclusion: The investigation will eventually help to develop more effective chemotherapeutic drugs from the natural source.