In-Droplet Electromechanical Cell Lysis and Enhanced Enzymatic Assay Driven by Ion Concentration Polarization.

Droplets enable the encapsulation of cells for their analysis in isolated domains. The study of molecular signatures (including genes, proteins, and metabolites) from a few or single cells is critical for identifying key subpopulations. However, dealing with biological analytes at low concentrations requires long incubation times and amplification to achieve the requisite signal strength. Further, cell lysis requires additional chemical lysing agents or heat, which can interfere with assays. Here, we leverage ion concentration polarization (ICP) in droplets to rapidly lyse breast cancer cells within 2 s under a DC voltage bias of 30 V. Numerical simulations attribute cell lysis to an ICP-based electric field and shear stress. We further achieve up to 19-fold concentration enrichment of an enzymatic assay product resulting from cell lysis and a 3.8-fold increase in the reaction rate during enrichment. Our technique for sensitive in-droplet cell analysis provides scope for rapid, high-throughput detection of low-abundance intracellular analytes.

Farming on Mars: Treatment of basaltic regolith soil and briny water simulants sustains plant growth.

A fundamental challenge in human missions to Mars is producing consumable foods efficiently with the in situ resources such as soil, water, nutrients and solar radiation available on Mars. The low nutrient content of martian soil and high salinity of water render them unfit for direct use for propagating food crops on Mars. It is therefore essential to develop strategies to enhance nutrient content in Mars soil and to desalinate briny water for long-term missions on Mars. We report simple and efficient strategies for treating basaltic regolith simulant soil and briny water simulant for suitable resources for growing plants. We show that alfalfa plants grow well in a nutrient-limited basaltic regolith simulant soil and that the alfalfa biomass can be used as a biofertilizer to sustain growth and production of turnip, radish and lettuce in the basaltic regolith simulant soil. Moreover, we show that marine cyanobacterium Synechococcus sp. PCC 7002 effectively desalinates the briny water simulant, and that desalination can be further enhanced by filtration through basalt-type volcanic rocks. Our findings indicate that it is possible to grow food crops with alfalfa treated basaltic regolith martian soil as a substratum watered with biodesalinated water.