When neurons undergo dramatic shape and volume changes, how is surface area adjusted appropriately? The membrane tension hypothesis-namely that high tensions favor recruitment of membrane to the surface whereas low tensions favor retrieval-provides a simple conceptual framework for surface area homeostasis. With membrane tension and area in a feedback loop, tension extremes may be averted even during excessive mechanical load variations. We tested this by measuring apparent membrane tension of swelling and shrinking Lymnaea neurons. With hypotonic medium (50%), tension that was calculated from membrane tether forces increased from 0.04 to as much as 0.4 mN/m, although at steady state, swollen-cell tension (0. 12 mN/m) exceeded controls only threefold. On reshrinking in isotonic medium, tension reduced to 0.02 mN/m, and at the substratum, membrane invaginated, creating transient vacuole-like dilations. Swelling increased membrane tension with or without BAPTA chelating cytoplasmic Ca2+, but with BAPTA, unmeasurably large (although not lytic) tension surges occurred in approximately two-thirds of neurons. Furthermore, in unarborized neurons voltage-clamped by perforated-patch in 50% medium, membrane capacitance increased 8%, which is indicative of increasing membrane area. The relatively damped swelling-tension responses of Lymnaea neurons (no BAPTA) were consistent with feedback regulation. BAPTA did not alter resting membrane tension, but the large surges during swelling of BAPTA-loaded neurons demonstrated that 50% medium was inherently treacherous and that tension regulation was impaired by subnormal cytoplasmic [Ca2+]. However, neurons did survive tension surges in the absence of Ca2+ signaling. The mechanism to avoid high-tension rupture may be the direct tension-driven recruitment of membrane stores.

For realizing scalable solar hydrogen synthesis, the development of visible-light-absorbing photocatalysts capable of overall water splitting is essential. Metal sulfides can capture visible light efficiently; however, their utilization in water splitting has long been plagued by the poor resilience against hole oxidation. Herein, we report that the ZnIn 2 S 4 monolayers with dual defects (Ag dopants and nanoholes) accessed via cation exchange display stoichiometric H 2 and O 2 evolution in pure water under visible light irradiation. In-depth characterization and modeling disclose that the dual-defect structure endows the ZnIn 2 S 4 monolayers with optimized light absorption and carrier dynamics. More significantly, the dual defects cooperatively function as active sites for water oxidation (Ag dopants) and reduction (nanoholes), thus leading to steady performance in photocatalytic overall water splitting without the assistance of cocatalysts. This work demonstrates a feasible way for fulfilling "all-in-one" photocatalyst design and manifests its great potential in addressing the stability issues associated with sulfide-based photocatalysts.

materials and enable innovative applications that are hard to achieve with current microelectronics. Examples vary from biointegrated devices for clinical diagnosis and treatment, [11][12][13] to electronic skin (E-Skin), [14][15][16] energy harvesting/storage devices, [17][18][19][20][21] and sweat sensor, [22,23] to flexible display, [24,25] and to RFID tags, [26,27] etc.Two main kinds of microfabrication processes have been developed for flexible electronics, including the solutionprocessable methods and vacuum-based methods (lithographic patterning and undercut etching). [28] The former is naturally compatible with flexible substrates and can deposit and pattern functional materials in one single step. [29][30][31] They have fabricated various printed electronics with increasing performance, such as conductive metal wires, [32][33][34] thin film transistors (TFTs), [35][36][37] and piezoelectric devices. [38][39][40][41] However, the electronic performance is still limited by the properties of solution-processable functional materials and low resolution of printing techniques, with respect to standard microfabrication process. [42] On the other side, vacuum-based microfabrication techniques provide wellestablished routes to realize high-performance electronics, but generally incompatible with large-area, flexible (polymeric substrates). Ideally, high performance flexible electronics systems are usually fabricated by built-up process that begins with independent fabrication of high-modulus, fragile, chip-scale elements (e.g., IC chips, MEMS, sensors, and power sources) or flexible devices (e.g., flexible sensor, flexible display, and TFT array) on donor wafers, followed by being transferred onto flexible/stretchable substrates.The above manufacturing routes of flexible electronics can be concluded as the transfer of the materials, components, and devices from original fabricated/prepared substrates to flexible ones. The most significant built-in challenge in transferring is to control of interface status to accommodate to the disparate nature of the transferred objects from donor wafer/substrate. Distinctive assembly techniques based on stress-induced interface fracture have been invented to be adaptive to the diversity of material properties and geometric sizes that lead to tremendous differences in mechanical properties. For those conventional rigid electronic components like IC chips, they are transferred by standard single-ejector needle pick-and-place It is challenging to manufacture large-area, ultrathin, flexible/stretchable electronics on an industrial scale. Recent ground-breaking advances in the manufacture of flexible electronics are based on powerful laser processes. Laser irradiation at an internally absorbing interface through a transparent substrate will bring various physical changes and chemical reactions at the interface, accompanied by distinct phenomena. Numerous techniques derived from these phenomena with the unique ability to fabricate materials, structures, and devices on flexible subst...

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Neurons are often regarded as fragile cells, easily destroyed by mechanical and osmotic insult. The results presented here demonstrate that this perception needs revision. Using extreme osmotic swelling, we show that molluscan neurons are astonishingly robust. In distilled water, a heterogeneous population of Lymnaea stagnalis CNS neurons swelled to several times their initial volume, yet had a ST50 (survival time for 50% of cells) > 60 min. Cells that were initially bigger survived longer. On return to normal medium, survivors were able, over the next 24 hr, to rearborize. Reversible membrane capacitance changes corresponding to about 0.7 muF/cm2 of apparent surface area accompanied neuronal swelling and shrinking in hypo- and hyperosmotic solutions; reversible changes in cell surface area evidently contributed to the neurons' ability to accommodate hydrostatic pressures then recover. The reversible membrane area/capacitance changes were not dependent on extracellular Ca2+. Neurons were monitored for potassium currents during direct mechanical inflation and during osmotically driven inflation. The latter but not the former stimulus routinely elicited small potassium currents, suggesting that tension increases activate the currents only if additional disruption of the cortex has occurred. Under stress in distilled water, a third of the neurons displayed a quite unexpected behavior: prolonged writhing of peripheral regions of the soma. This suggested that a plasma membrane-linked contractile machinery (presumably actomyosin) might contribute to the neurons' mechano-osmotic robustness by restricting water influx. Consistent with this possibility, 1 mM N-ethyl-maleimide, which inhibits myosin ATPase, decreased the ST50 to 18 min, rendered the survival time independent of initial size, and abolished writhing activity. For neurons, active mechanical resistance of the submembranous cortex, along with the mechanical compliance supplied by insertion or eversion of membrane stores may account for the ability to withstand diverse mechanical stresses. Mechanical robustness such as that displayed here could be an asset during neuronal outgrowth or regeneration.

Mechanosensitive (MS) channels, ones whose open probability varies with membrane tension in patch recordings, are diverse and ubiquitous, yet many are remarkably insensitive to mechanical stimuli in situ. Failure to elicit mechanocurrents from cells with abundant MS channels suggests that, in situ, the channels are protected from mechanical stimuli. To establish what conditions affect MS channel gating, we monitored Lymnaea neuron stretch-activated K (SAK) channels in cell-attached patches after diverse treatments. Mechanosensitivity was gauged by rapidity of onset and extent of channel activation during a step pressure applied to a “naive” patch. The following treatments enhanced mechanosensitivity: actin depolymerization (cytochalasin B), N-ethylmaleimide, an inhibitor of ATPases including myosin, elevated Ca (using A-23187), and osmotic swelling (acutely and after 24 h). Osmotic shrinking decreased mechanosensitivity. A unifying interpretation is that traumatized cortical cytoskeleton cannot prevent transmission of mechanical stimuli to plasma membrane channels. Mechanoprotection and capricious mechanosensitivity are impediments to cloning efforts with MS channels. We demonstrate a potpourri of endogenous MS currents from L-M(TK−) fibroblasts; others had reported these cells to be MS current null and hence to be suitable for expressing putative MS channels.

We have explored the synthesis of Au@Hg x Cd 1-x Te core@shell nanorods by sequential aqueous cation exchange (ACE) for near-infrared photodetector application. A number of related Au@telluride core/shell nanorod structures were put forwarded, taking advantage of multi-step transformations through a binary and then a ternary phase for the telluride shells. The latter have a high degree of crystallinity thanks to the step-wise ACE method. The use of only trace amounts of Cd 2+ coordinated with tri-n-butylphosphine, assisted the phase transformation from an amorphous Ag 2 Te shell to a highly crystalline Ag 3 AuTe 2 shell in the first stage; this was followed by a further cation exchange (CE) step with far higher Cd 2+ levels to fabricate a highly crystalline CdTe shell, and with an additional CE with Hg 2+ to convert it to a Hg x Cd 1-x Te shell. The composition of the shell components and the well-controlled thickness of the shells enabled tunable surface plasmon resonance properties of the Au@telluride nanorods in the NIR region. Utilizing the enhanced NIR absorption, a hybrid photodetector structure of Au@Hg x Cd 1-x Te nanorods on graphene was fabricated, showing visible to NIR (vis-NIR) broadband detection with high photoresponsivity (~10 6 A/W).