Self‐Assembled “Breathing” Grana‐Like Cisternae Stacks

Membranes in cells display elaborate, dynamic morphologies intimately tied to defined cellular functions. Cisternae stacks are a common membrane morphology in cells widely found in organelles. However, compared with the well‐studied spherical cell membrane mimics, cisternae stacks as organelle membrane mimics are greatly neglected because of the difficulty of fabricating this unique structure. Herein, the grana‐like cisternae stacks are assembled via the reorganization of stacked microsized bicelles to mimic grana functions. The cisternae stacks are connected by fusion regions between adjacent cisternae. The number of cisternae can be controlled from ≈4 to 15 by the variation of ethanol volume percentage. Under the stimulation of solvent or negatively charged nanoparticles, the cisternae stacks can reversibly compress and expand, similar to the “breathing” property of natural grana. During the “breathing” process, nanoparticles are reversibly captured and released. Frequency resonance energy transfer is realized on the cisternae stacks trapped with two kinds of quantum dots. The cisternae stacks provide advanced membrane model for cell biotechnology, and clues for the shaping of organelles composed of cisternae. The ability of the cisternae stacks to capture materials enables them to possibly be applied in biomimetics and the design of advanced functional materials.     

Developing a “Water‐Defendable” and “Dendrite‐Free” Lithium‐Metal Anode Using a Simple and Promising GeCl4 Pretreatment Method

Lithium metal is an ultimate anode in “next‐generation” rechargeable batteries, such as Li–sulfur batteries and Li–air (Li–O₂) batteries. However, uncontrollable dendritic Li growth and water attack have prevented its practical applications, especially for open‐system Li–O₂ batteries. Here, it is reported that the issues can be addressed via the facile process of immersing the Li metal in organic GeCl₄–THF steam for several minutes before battery assembly. This creates a 1.5 µm thick protection layer composed of Ge, GeO_x, Li₂CO₃, LiOH, LiCl, and Li₂O on Li surface that allows stable cycling of Li electrodes both in Li‐symmetrical cells and Li–O₂ cells, especially in “moist” electrolytes (with 1000–10 000 ppm H₂O) and humid O₂ atmosphere (relative humidity (RH) of 45%). This work illustrates a simple and effective way for the unfettered development of Li‐metal‐based batteries.     

Single‐Layer Ternary Chalcogenide Nanosheet as a Fluorescence‐Based “Capture‐Release” Biomolecular Nanosensor

The novel application of two‐dimensional (2D) single‐layer ternary chalcogenide nanosheets as “capture‐release” fluorescence‐based biomolecular nanosensors is demonstrated. Fluorescently labeled biomolecular probe is first captured by the ultrathin Ta₂NiS₅ nanosheets and then released upon adding analyte containing a target biomolecule due to the higher probe‐target affinity. Here, the authors use a nucleic acid probe for the model target biomolecule Plasmodium lactate dehydrogenase, which is an important malarial biomarker. The ultrathin Ta₂NiS₅ nanosheet serves as a highly efficient fluorescence quencher and the nanosensor developed from the nanosheet is highly sensitive and specific toward the target biomolecule. Apart from the specificity toward the target biomolecule in homogeneous solutions, the developed nanosensor is capable of detecting and differentiating the target in heterogeneous solutions consisting of either a mixture of biomolecules or serum, with exceptional specificity. The simplicity of the “capture‐release” method, by eliminating the need for preincubation of the probe with the test sample, may facilitate further development of portable and rapid biosensors. The authors anticipate that this ternary chalcogenide nanosheet‐based biomolecular nanosensor will be useful for the rapid detection and differentiation of a wide range of chemical and biological species.