Low-cost,μm-thick,tape-free electronic tattoo sensors with minimized motion and sweat artifacts

Electronic tattoos(e-tattoos),also known as epidermal electronics,are ultra-thin and ultra-soft noninvasive but skin-conformable devices with capabilities including physiological sensing and transdermal stimulation and therapeutics.The fabrication of e-tattoos out of conventional inorganic electronic materials used to be tedious and expensive.Recently developed cut-and-paste method has significantly simplified the process and lowered the cost.However,existing cut-and-paste method entails a medical tape on which the electronic tattoo sensors should be pasted,which increases tattoo thickness and degrades its breathability.To address this problem,here we report a slightly modified cut-and-paste method to fabricate low-cost,open-mesh e-tattoos with a total thickness of just 1.5μm.E-tattoos of such thinness can be directly pasted on human skin and conforms to natural skin texture.We demonstrate that this ultra-thin,tape-free e-tattoo can confidently measure electrocardiogram(ECG),skin temperature,and skin hydration.Heart rate and even respiratory rate can be extracted from the ECG signals.A special advantage of such ultra-thin e-tattoo is that it is capable of high-fidelity sensing with minimized motion artifacts under various body movements.Effects of perspiration are found to be insignificant due to the breathability of such e-tattoos.

“Cut-and-paste” method for the rapid prototyping of soft electronics

Unlike wafer-based rigid electronics, soft electronics have many unique advantages including thinness, flexibility, stretchability,conformability, lightweight, large area, as well as low cost. As a result, they have demonstrated many emerging capabilities in healthcare devices, soft robotics, and human-machine interface. Instead of conventional microfabrication, there is an evergrowing interest in the freeform or digital manufacture of soft electronics. This review provides a survey for a cost-and timeeffective subtractive manufacturing process called the "cut-and-paste" method. It employs a mechanical cutter plotter to form patterns on various electronically functional membranes such as sheets of metals, functional polymers, and even two-dimensional(2D) materials, supported by a temporary tape. The patterned membranes can then be pasted on soft substrates such as medical tapes or even human skin. This process is completely dry and desktop. It does not involve any rigid wafers and is hence capable of making large-area electronics. The process can be repeated to integrate multiple materials on a single substrate.Integrated circuits(ICs) and rigid components can be added through a "cut-solder-paste" process. Multilayer devices can also be fabricated through lamination. We therefore advocate that the "cut-and-paste" method is a very versatile approach for the rapid prototyping of soft electronics for various applications.

Precise Detection and Visualization of Cyclooxygenase-2 for Golgi Imaging by a Light-Up AggregationInduced Emission-Based Probe

Precision-targeted detection of cancer in a rapid and sensitive fashion remains a significant challenge in prevention,management,and in particular,treatment.Herein,we have designed and synthesized a unique cyclooxygenase-2(COX-2)fluorescence probe,dimethylamine-9,10-distyrylanthracene-indomethacin(NDSA-IMC),that could visualize the site of highly expressed COX-2 in the Golgi apparatus of cancer cells,using 9,10-diatyrylanthracene derivative as the luminous unit and a selective inhibitor,indomethacin(IMC),as the recognizing moiety for COX-2.In an aqueous solution,the free state NDSA-IMC showed a weak emission in the absence of COX-2 but enhanced emission in the presence of the enzyme due to the restriction of intramolecular motion of aggregation-induced emission-active NDSA-IMC when bound to COX-2.Cell imaging and flow cytometry experiments indicated that NDSA-IMC could discriminate between cancer and normal cells and visualize the Golgi apparatus of cancer cells via specific targeting of COX-2.Therefore,NDSA-IMC might potentially detect early cancer lesions and ultimately mitigate the population of cancer burden in society.

Utilizing morpholine for purely organic room temperature phosphors

In this article,morpholine,a non-conjugated heterocycle,is embedded intoπsystem to construct single-component organic room temperature phosphorescence(RTP)luminogens.The effect of morpholine on intermolecular interaction,crystal packing modes,and RTP performance is investigated systematically.The experimental and theoretical calculation results illustrate the versatility of morpholine in promoting the n-π*transition and intensifying the intermolecular interactions,which not only enhances the generation of triplet excitons,but also suppresses the nonradiative decay of triplet excitons.Impressively,TMPh containing three morpholine units shows an ultralong lifetime of 1.03 s and a visible afterglow up to 10 s.The unique dual delayed emission and long afterglow property allow potential application of morpholine derivatives in data encryption,and the time-dependent color change of afterglow emission is realized after removing the excitation source,providing a high-level data security.This article provides a new perspective for the design of purely organic RTP system without utilization of metal,or even any heavy atoms.

Twisted Intramolecular Charge Transfer—Aggregation-Induced Emission Fluorogen with Polymer Encapsulation-Enhanced NearInfrared Emission for Bioimaging

Fluorescence probes with strong near-infrared(NIR)emission and water solubility are considered useful visualization tools for localization marking as well as investigating cell migration and transplantation.Here,we designed and synthesized a new donor–π–acceptor(D–π–A)fluorogen,2-(4-[(E)-4-(diphenylamino)styryl]phenyl)-3-(4′-[1,2,2-triphenylvinyl]-[1,1′-biphenyl]-4-yl)fumaronitrile(TB-TPE).TB-TPE exhibits twisted intramolecular charge transfer(TICT)and aggregation-induced emission(AIE)in the NIR region,with an emission peak at 714 nm and a fluorescence quantum yield(Qy)of 6.6%in the solid state.By encapsulating TB-TPE with polystyrene–polyethylene glycol(PS-PEG),watersoluble TB-TPE-PS-PEG nanoparticles(TP NPs)are fabricated,which display polymer encapsulationenhanced emission with a Qy of 46.5%due to the strong restriction effect on the TICT process and the destruction of H aggregation for TB-TPE by the polymer matrix.Au-coated Fe_(3)O_(4)(Fe_(3)O_(4)@Au)nanocrystals were then embedded in the TP NPs to form highly fluorescent TB-TPE-Fe_(3)O_(4)-Au-PS-PEG nanoparticles(TFAP NPs)with a Qy of 39.7%.Our demonstration of successful cellular imaging of TP NPs for Hep-G2 cells and multimodality imaging of TFAP NPs in mouse liver tumors indicates that polymer-encapsulated TB-TPE offers great prospects as a multifunctional fluorescence probe for bioimaging.

Highly Efficient Blue Organic Light-Emitting Diode Based on a Pyrene[4,5-d]Imidazole-Pyrene Molecule

Organic light-emitting diodes(OLEDs),which have been recently utilized in some flat-panel display screens such as mobile phones and televisions,show many merits,including light weight,high flexibility,energy preservation,and so forth,and are considered the next-generation displays and solid-state lightings.Blue-emitting materials that can be applied in nondoped OLEDs with little efficiency roll-offs at high brightness are of great importance.Here,a highly efficient,blue-emitting material,9-phenyl10-(4-(pyren-1-yl)phenyl)-9H-pyreno[4,5-d]imidazole(PyPI-Py),is achieved using pyrene[4,5-d]imidazole and pyrene as the weak electron donor and electron acceptor,respectively.The nondoped blue OLED exhibits excellent performance with a maximum brightness of 75,687 cd m^(−2),a maximum current efficiency of 13.38 cd A−1,and a maximum external quantum efficiency(ηext)of 8.52%.Moreover,theηext is maintained at 8.35%and 8.05%at a brightness of 10,000 and 50,000 cd m^(−2),respectively,displaying extremely small efficiency roll-offs of 2.0%and 5.5%.The device characteristics are among the highest values for nondoped blue OLEDs and correspond to the best performance obtained for nondoped pyrene-based blue OLEDs.The superior performance is attributed to the proper donor–acceptor design strategy which results in a quasi-equivalent hybrid local and charge-transfer excited state with the maximum generation of an 82%fraction of singlet excitons.