All printable snow-based triboelectric nanogenerator.

The development of power generators that can function in harsh snowy environments and in contact with snow can be beneficial but challenging to accomplish. Herein, we introduce the first snow-based triboelectric nanogenerator (snow-TENG) that can be used as an energy harvester and a multifunctional sensor based on the principle of snow-triboelectrification. In this work, we used a 3D printing technique for the precise design and deposition of the electrode and triboelectric layer, leading to flexible, stretchable and metal-free triboelectric generators.

Automated 4-Sample Protein Immunoassays using 3D-Printed Microfluidics.

Low cost, miniaturized assay platforms that work with small sample volumes, high sensitivity and rapid detection will have high value in future biomolecular diagnostics. Herein we report an automated, 3D printed electrochemiluminescent (ECL) immunoarray integrated with a nanostructured pyrolytic graphite sheet (PGS) microwell chip configured to detect 2 proteins simultaneously from complex liquid samples with high sensitivity and selectivity. Assays are done in 18 min at cost of < $1.

An Ultra-Shapeable, Smart Sensing Platform Based on a Multimodal Ferrofluid-Infused Surface.

The development of wearable, all-in-one sensors that can simultaneously monitor several hazard conditions in a real-time fashion imposes the emergent requirement for a smart and stretchable hazard avoidance sensing platform that is stretchable and skin-like. Multifunctional sensors with these features are problematic and challenging to accomplish. In this context, a multimodal ferrofluid-based triboelectric nanogenerator (FO-TENG), featuring sensing capabilities to a variety of hazard stimulus such as a strong magnetic field, noise level, and falling or drowning is reported.

Automated 3D-Printed Microfluidic Array for Rapid Nanomaterial-Enhanced Detection of Multiple Proteins.

We report here the fabrication and validation of a novel 3D-printed, automated immunoarray to detect multiple proteins with ultralow detection limits. This low cost, miniature immunoarray employs electrochemiluminescent (ECL) detection measured with a CCD camera and employs touch-screen control of a micropump to facilitate automated use. The miniaturized array features prefilled reservoirs to deliver sample and reagents to a paper-thin pyrolytic graphite microwell detection chip to complete sandwich immunoassays.

Disposable inkjet-printed electrochemical platform for detection of clinically relevant HER-2 breast cancer biomarker.

Rapidly fabricated, disposable sensor platforms hold tremendous promise for point-of-care detection. Here, we present an inexpensive (< $0.25) fully inkjet printed electrochemical sensor with integrated counter, reference, and working electrodes that is easily scalable for commercial fabrication.

Ultrathin Graphene-Protein Supercapacitors for Miniaturized Bioelectronics.

Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described.

Electrocatalytic Oxidation of Alcohols, Tripropylamine, and DNA with Ligand-Free Gold Nanoclusters on Nitrided Carbon.

Electrocatalytic properties of ligand-free gold nanoclusters (AuNCs, <2 nm) grown on nitrided carbon supports (denoted as AuNCs@N-C) were evaluated for the oxidation of representative organic molecules including alcohols, an amine, and deoxyguanosine in oligonucleotides. AuNCs@N-C catalysts were incorporated into films of architecture {PDDA/AuNCs@N-C} by using layer-by-layer assembly with oppositely charged poly(diallyldimethylammonium) (PDDA) on pyrolytic graphite (PG) electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to survey the electrocatalytic properties of these AuNCs@N-C films.

Microfluidic array for simultaneous detection of DNA oxidation and DNA-adduct damage.

Exposure to chemical pollutants and pharmaceuticals may cause health issues caused by metabolite-related toxicity. This paper reports a new microfluidic electrochemical sensor array with the ability to simultaneously detect common types of DNA damage including oxidation and nucleobase adduct formation. Sensors in the 8-electrode screen-printed carbon array were coated with thin films of metallopolymers osmium or ruthenium bipyridyl-poly(vinylpyridine) chloride (OsPVP, RuPVP) along with DNA and metabolic enzymes by layer-by-layer electrostatic assembly.

Electrochemiluminescent Array to Detect Oxidative Damage in ds-DNA Using [Os(bpy)(phen-benz-COOH)]/Nafion/Graphene Films.

Reactive oxygen species (ROS) oxidize guanosines in DNA to form 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG), a biomarker for oxidative stress. Herein we describe a novel 64-microwell electrochemiluminescent (ECL) array enabling sensitive multiplexed detection of 8-oxodG in ds-DNA without hydrolysis. Films of Nafion and reduced graphene oxide containing ECL dye [Os(bpy)(phen-benz-COOH)] (OsNG, {bpy= 2,2'-bipyridine and phen-benz-COOH = (4-(1,10-phenanthrolin-6-yl) benzoic acid)}) were assembled into microwells on a pyrolytic graphite wafer to detect 8-oxodG in oligonucleotides by electrochemiluminescence (ECL).

Ligand-Free Noble Metal Nanocluster Catalysts on Carbon Supports via "Soft" Nitriding.

We report a robust, universal "soft" nitriding method to grow in situ ligand-free ultrasmall noble metal nanocatalysts (UNMN; e.g., Au, Pd, and Pt) onto carbon.

3D-printed supercapacitor-powered electrochemiluminescent protein immunoarray.

Herein we report a low cost, sensitive, supercapacitor-powered electrochemiluminescent (ECL) protein immunoarray fabricated by an inexpensive 3-dimensional (3D) printer. The immunosensor detects three cancer biomarker proteins in serum within 35 min. The 3D-printed device employs hand screen printed carbon sensors with gravity flow for sample/reagent delivery and washing.

Facet-dependent catalytic activity of MnO electrocatalysts for oxygen reduction and oxygen evolution reactions.

This Communication highlights the facet-dependent electrocatalytic activity of MnO nanocrystals for OERs/ORRs. The MnO(100) facets with higher adsorption energy of O species can largely promote the electrocatalytic activity.