Costas P . Grigoropoulos

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We report gas and water flow measurements through microfabricated membranes in which aligned carbon nanotubes with diameters of less than 2 nanometers serve as pores. The measured gas flow exceeds predictions of the Knudsen diffusion model by more than an order of magnitude. The measured water flow exceeds values calculated from continuum hydrodynamics(More)
A human in vitro cardiac tissue model would be a significant advancement for understanding, studying, and developing new strategies for treating cardiac arrhythmias and related cardiovascular diseases. We developed an in vitro model of three-dimensional (3D) human cardiac tissue by populating synthetic filamentous matrices with cardiomyocytes derived from(More)
Biological pores regulate the cellular traffic of a large variety of solutes, often with high selectivity and fast flow rates. These pores share several common structural features: the inner surface of the pore is frequently lined with hydrophobic residues, and the selectivity filter regions often contain charged functional groups. Hydrophobic,(More)
In this paper, in order to increase the power conversion efficiency we demonstrated the selective growth of "nanoforest" composed of high density, long branched "treelike" multigeneration hierarchical ZnO nanowire photoanodes. The overall light-conversion efficiency of the branched ZnO nanowire DSSCs was almost 5 times higher than the efficiency of DSSCs(More)
Electrospun scaffolds are used extensively in tissue-engineering applications as they offer a cell-friendly microenvironment. However, one major limitation is the dense fibers, small pore size and consequently poor cell infiltration. Here, we employ a femtosecond (FS) laser system to ablate and create microscale features on electrospun poly(L-lactide)(More)
Tissue morphogenesis and organ formation are the consequences of biochemical and biophysical cues that lead to cellular spatial patterning in development. To model such events in vitro, we use PEG-patterned substrates to geometrically confine human pluripotent stem cell colonies and spatially present mechanical stress. Modulation of the WNT/β-catenin(More)
Smooth inner pores of carbon nanotubes (CNT) provide a fascinating model for studying biological transport. We used an atomic force microscope to pull a single-stranded DNA oligomer from a carbon nanotube pore. DNA extraction from CNT pores occurs at a nearly constant force, which is drastically different from the elastic profile commonly observed during(More)
Modern means of communication rely on electric fields and currents to carry the flow of information. In contrast, biological systems follow a different paradigm that uses ion gradients and currents, flows of small molecules, and membrane electric potentials. Living organisms use a sophisticated arsenal of membrane receptors, channels, and pumps to control(More)
There is much interest in developing synthetic analogues of biological membrane channels with high efficiency and exquisite selectivity for transporting ions and molecules. Bottom-up and top-down methods can produce nanopores of a size comparable to that of endogenous protein channels, but replicating their affinity and transport properties remains(More)
Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electronics fabrication methods are well developed for rigid substrates, direct application or slight(More)