On-chip mixing of cancer cells and drug using LED enabled 2D opto-wetting droplet platforms.

Droplets of microliter size serve as miniaturized reaction chambers for practical lab on a chip (LoC) applications. The transportation and coalescence of droplets are indispensable for realizing microfluidic mixing. Light can be used as an effective tool for droplet manipulation. We report a novel platform for LED-based transport and mixing of cell-encapsulated microdroplets for evaluating dose response of cancer drugs. Microcontroller enabled LEDs (Light-emitting diodes) were used to actuate droplet movement on Azobenzene coated planar silicon substrates. Droplet transport was initiated by the spatial gradient in solid-liquid interfacial tension developed through LED triggered photoisomerization of Azobenzene substrate. Detailed UV-Visible characterization of Azobenzene molecule was performed for different LED light intensities and wavelengths. A complete standalone opto-wetting toolbox was developed by integrating various components such as a microcontroller, UV LED (385 nm), blue LED (465 nm), and Azobenzene coated photoresponsive substrate. 2D transport of DI water droplets (10-30µl) along simple trajectories was demonstrated using this device. Subsequently, the proposed opto-wetting platform was used for performing drug evaluation through on-chip mixing of droplets containing cancer cells (A549-Lung cancer cells) and cancer drug (paclitaxel). Separate cell viability analysis was performed using MTT assays, where the cytocompatibility of Azobenzene and UV light (385 nm) on A549 cells were studied. The dosage response of paclitaxel drug was studied using both MTT (3-(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) and live-dead cell assays. The results obtained indicate the potential use of our device as a cost-effective, reliable opto-wetting microfluidic platform for drug screening experiments.

Effect of Marine Basidiomycetes Fulvifomes sp.-Derived Ergosterol Peroxide on Cytotoxicity and Apoptosis Induction in MCF-7 Cell Line.

The aim of the present study is to extract the bioactive compounds which can induce the apoptosis in breast cancer cell line MCF-7 by marine basidiomycetes. Internal Transcribed Spacer (ITS) sequences based molecular taxonomic study confirmed that collected the marine basidiomycetes belongs to Fulvifomes sp. Further, the isolated compounds from the Fulvifomes sp. confirmed as ergosterol peroxide (EP) by spectroscopic studies. The compound inhibited 50% of the cell growth (IC50) at the concentration of 40 µg/mL and induced 90% cell death (IC 90) at the concentration of 80 µg/mL. The ergosterol peroxide generated Reactive Oxygen Species (ROS) and induced apoptotic cell death in MCF-7. Ethidium bromide/Acridine Orange (Et/Br) staining showed the increased number of early and late apoptosis in treated MCF-7 cells. The compounds treated cells indicated the significant loss of mitochondrial membrane potential (Δψm) with p < 0.05. The induction of apoptosis by marine basidiomycetes derived ergosterol peroxide was confirmed by chromatin condensation in MCF7 cells using Hoechst staining 33342.