Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics

Few-layer black phosphorus (BP) is a new two-dimensional material which is of great interest for applications, mainly in electronics. However, its lack of environmental stability severely limits its synthesis and processing. Here we demonstrate that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liquid phase exfoliation under ambient conditions in solvents such as N-cyclohexyl-2-pyrrolidone (CHP). Nanosheets are surprisingly stable in CHP, probably due to the solvation shell protecting the nanosheets from reacting with water or oxygen. Experiments, supported by simulations, show reactions to occur only at the nanosheet edge, with the rate and extent of the reaction dependent on the water/oxygen content. We demonstrate that liquid-exfoliated BP nanosheets are potentially useful in a range of applications from ultrafast saturable absorbers to gas sensors to fillers for composite reinforcement

Modelling the Cytotoxicity of Cisplatin

Cisplatin has been the mainstay of chemotherapeutic efforts against several types of cancers for over 30 years. However, there is still much that is unknown regarding its mechanism of action. The several serious side effects of cisplatin therapy and the lack of consensus regarding the ideal dosage regimen necessitate the development of a quantitative model for cisplatin action. A first-level mathematical model is presented for the cytotcodcity of cisplatin which predicts the survival of cancer cells when subjected to a given dose of this antitumor drug. This model comprises of (i) an uptake model that describes the movement of cisplatin molecules from the extracellular medium to the cell nucleus and the formation (and repair) of cisiplatin-DNA adducts and (ii) a tolerance model that relates the quantity of cisplatin-DNA adducts formed inside the cell nuclei in a tumor to the fraction of tumor cells that are killed. The predictions of the model are in good agreement with in vitro experimental data obtained for carcinoma cell lines. To the best of our knowledge, this is the first model combining the uptake of cisplatin (consistent with the biochemical mechanism of action) with cell death (based on cisplatin-DNA adducts). It predicts a Pareto-type set of dosage regimen (dosage, C(ext), vs exposure time, t(exp)) of cisplatin to obtain a desired chemotherapeutic efficacy. Some reported patient-data is consistent with this prediction

Actuation of Janus Emulsion Droplets via Optothermally Induced Marangoni Forces.

Microscale Janus emulsions represent a versatile material platform for dynamic refractive, reflective, and light-emitting optical components. Here, we present a mechanism for droplet actuation that exploits thermocapillarity. Using optically induced thermal gradients, an interfacial tension differential is generated across the surfactant-free internal capillary interface of Janus droplets. The interfacial tension differential causes droplet-internal Marangoni flows and a net torque, resulting in a predictable and controllable reorientation of the droplets. The effect can be quantitatively described with a simple model that balances gravitational and thermal torques. Occurring in small thermal gradients, these optothermally induced Marangoni dynamics represent a promising mechanism for controlling droplet-based micro-optical components

Reconfigurable and responsive droplet-based compound micro-lenses.

Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications-integral micro-scale imaging devices and light field display technology-thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses