A moisture-enabled fully printable power source inspired by electric eels.

Great efforts have been made to build integrated devices to enable future wearable electronics; however, safe, disposable, and cost-effective power sources still remain a challenge. In this paper, an all-solid-state power source was developed by using graphene materials and can be printed directly on an insulating substrate such as paper. The design of the power source was inspired by electric eels to produce programmable voltage and current by converting the chemical potential energy of the ion gradient to electric energy in the presence of moisture. An ultrahigh voltage of 192 V with 175 cells in series printed on a strip of paper was realized under ambient conditions. For the planar cell, the mathematical fractal design concept was adapted as printed patterns, improving the output power density to 2.5 mW cm-3, comparable to that of lithium thin-film batteries. A foldable three-dimensional (3D) cell was also achieved by employing an origami strategy, demonstrating a versatile design to provide green electric energy. Unlike typical batteries, this power source printed on flexible paper substrate does not require liquid electrolytes, hazardous components, or complicated fabrication processes and is highly customizable to meet the demands of wearable electronics and Internet of Things applications.

Aqueous OH-/H+ dual-ion gradient assisted electricity effective electro-organic synthesis of 2,5-furandicarboxylic acid paired with hydrogen fuel generation.

The OH-/H+ dual-ion gradient has a hidden electromotive force of 0.82 V under standard conditions; however, its non-redox nature completely prevents its direct interconversion as electrical driving force. We show by using organic molecules whose heterogeneous electron transfer is pH dependent, OH-/H+ dual-ion energy can be directly harvested as electrical driving force for performing simultaneous electro-organic synthesis and hydrogen fuel production in an electricity effective manner. To demonstrate this dual-ion gradient assisted electro-organic synthesis, 5-hydroxymethylfurfural (HMF) is chosen as the model molecule because of the immense techno commercial applications of its oxidized products. This dual-ion assisted device only required âˆ¼1 V to provide a current density of 50 mA/cm2 and for achieving the same rate; the traditional state-of-the-art electrolytic cell required a doubling of the applied potential. The dual-ion gradient assisted device can convert biomass-derived HMF to economically important FDCA with âˆ¼90 % yield and âˆ¼87 % Faradaic efficiency with simultaneous H2 fuel production at a potential as low as 1 V.

Patched 1 reduces the accessibility of cholesterol in the outer leaflet of membranes.

A long-standing mystery in vertebrate Hedgehog signaling is how Patched 1 (PTCH1), the receptor for Hedgehog ligands, inhibits the activity of Smoothened, the protein that transmits the signal across the membrane. We previously proposed (Kinnebrew et al., 2019) that PTCH1 inhibits Smoothened by depleting accessible cholesterol from the ciliary membrane. Using a new imaging-based assay to directly measure the transport activity of PTCH1, we find that PTCH1 depletes accessible cholesterol from the outer leaflet of the plasma membrane. This transport activity is terminated by binding of Hedgehog ligands to PTCH1 or by dissipation of the transmembrane potassium gradient. These results point to the unexpected model that PTCH1 moves cholesterol from the outer to the inner leaflet of the membrane in exchange for potassium ion export in the opposite direction. Our study provides a plausible solution for how PTCH1 inhibits SMO by changing the organization of cholesterol in membranes and establishes a general framework for studying how proteins change cholesterol accessibility to regulate membrane-dependent processes in cells.

Single-ligand dual-targeting irinotecan liposomes: Control of targeting ligand display by pH-responsive PEG-shedding strategy to enhance tumor-specific therapy and attenuate toxicity.

Along with the malignant proliferation of tumor requiring nutrients, the expression of L-type amino acid transporter 1(LAT1) and amino acid transporter B0,+ (ATB0,+) in cancer cells is up-regulated that can be used as new targets for active targeting of tumor. However, since normal cells also express amino acid transporters in small amounts, traditional ligand-exposure drug delivery systems are potentially toxic to the body. Therefore, we designed a smart-response drug delivery system that buries the tyrosine ligand in PEG hydration layer at normal tissues and exposes the ligand by cleaving the pH-sensitive bond of PEG at the tumor site. Irinotecan (CPT-11) is actively loaded into the inner aqueous phase of liposomes via a copper ion gradient mechanism which has high encapsulation efficiency and stable drug release profile. Smart-response liposomes showed the strongest cytotoxicity and the maximum cellular uptake in vitro, the largest amount of tumor site accumulation and the best antitumor effect in vivo, compared with non-targeted liposomes and non-sensitive liposomes. It is worth noting that smart-response liposomes not only achieved enhanced antitumor effect but also attenuated side effects compared to ligand-exposure liposomes. This provides a smart responsive drug delivery system for precise treatment and shows a good application prospect.

Enhanced transport into and out of dead-end pores.

Dead-end micro- and nanoscale channels are ubiquitous in nature and are found in geological and biological systems subject to frequent disruptions. Achieving fluid flows in them is not possible through conventional pressure-driven mechanisms. Here we show that chemically driven convective flows leading to transport in and out of dead-end pores can occur by the phenomenon of "transient diffusioosmosis". The advective velocity depends on the presence of an in situ-generated transient ion gradient and the intrinsic charge on the pore wall. The flows can reach speeds of 50 µm/s and cause extraction of otherwise-trapped materials. Our results illustrate that chemical energy, in the form of a transient salt gradient, can be transduced into mechanical motion with the pore wall acting as the pump. As discussed, the phenomena may underlie observed transport in many geological and biological systems involving tight or dead-end micro- and nanochannels.

The application of EDTA in drug delivery systems: doxorubicin liposomes loaded via NH4EDTA gradient.

The applications of ethylenediaminetetraacetic acid (EDTA) have been expanded from the treatment of heavy metal poisoning to chelation therapies for atherosclerosis, heart disease, and cancers, in which EDTA reduces morbidity and mortality by chelating toxic metal ions. In this study, EDTA was used in a drug delivery system by adopting an NH4EDTA gradient method to load doxorubicin into liposomes with the goal of increasing therapeutic effects and decreasing drug-related cytotoxicity. The particle size of the optimum NH4EDTA gradient liposomes was 79.4±1.87 nm, and the entrapment efficiency was 95.54%±0.59%. In vitro studies revealed that liposomes prepared using an NH4EDTA gradient possessed long-term stability and delayed drug release. The in vivo studies also showed the superiority of the new doxorubicin formulation. Compared with an equivalent drug dose (5 mg/kg) prepared by (NH4)2SO4 gradient, NH4EDTA gradient liposomes showed no significant differences in tumor inhibition ratio, but cardiotoxicity and liposome-related immune organ damage were lower, and no drug-related deaths were observed. These results show that use of the NH4EDTA gradient method to load doxorubicin into liposomes could significantly reduce drug toxicity without influencing antitumor activity.