Digitally Controlled Printing of Bioink Barriers for Paper-Based Analytical Devices: An Environmentally Friendly One-Step Approach.

The patterning of hydrophilic paper with hydrophobic materials has emerged as an interesting method for the fabrication of paper-based devices (PADs). Herein, we demonstrate a digitally automated, easy, low-cost, eco-friendly, and readily available method to create highly hydrophobic barriers on paper that can be promptly employed with PADs by simply using a bioink made with rosin, a commercially available natural resin obtained from conifer trees. The bioink can be easily delivered with the use of a ballpoint pen to produce water- and organic solvent-resistant barriers, showing superior properties when compared to other methods such as wax-printing or permanent markers. The approach enables the pen to be attached to a commercially available cutting printer to perform the semiautomated fabrication of hydrophobic barriers for PADs. With the aid of digitally controlled optimization, together with features of machine learning and design of experiments, we show a thorough investigation on the barrier strength that can be further adjusted to the desired application's needs. Then, we explored the barrier sturdiness across various uses, such as wide range aqueous pH sensing and the harsh acidic/organic conditions needed for the colorimetric detection of cholecalciferol.

Rapid Screening of Biomarkers in KYSE-150 Cells Exposed to Polycyclic Aromatic Hydrocarbons via Inkjet Printing Single-Cell Mass Spectrometry.

Single-cell analysis by mass spectrometry (MS) is emerging as a powerful tool that not only contributes to cellular heterogeneity but also offers an unprecedented opportunity to predict pathology onset and facilitates novel biomarker discovery. However, the development of single-cell MS analysis techniques with a focus on sample extraction, separation, and ionization methods for volume-limited samples and complexity of cellular samples are still a big challenge. In this study, we present a high-throughput approach to inkjet drop on demand printing single-cell MS for rapid screening of biomarkers of polycyclic aromatic hydrocarbon (PAH) exposure at the KYSE-150 cell, aiming to elucidate the pathogenesis of PAH-induced esophageal cancer. With an analytical bulk KYSE-150 cell throughput of up to 51 cells per minute, the method provides a new opportunity for simultaneous single-cell analysis of multiple biomarkers. We screened 930 characteristic ions from 3,683 detected peak signals and identified 91 distinctive molecules that exhibited significant differences under various concentrations of PAH exposure. These molecules have potential as clinical diagnostic biomarkers. Additionally, the current study identifies specific biomarkers that behave completely opposite in single-cell and multicell lipidomics as the concentration of PAH changes. These biomarkers potentially subdivide KYSE-150 cells into PAH-sensitive and PAH-insensitive types, providing a basis for revealing PAH toxicity and disease pathogenesis from the heterogeneity of cellular metabolism.

Inkjet Printing Patterned Plasmonic SERS Platform with Surface-Optimized Paper for Label-Free Detection of Illegal Drugs in Urine.

Rapid quantitative testing of illegal drugs is urgently needed for precisely cracking down on drug crimes. Herein, an optimized paper-based surface-enhanced Raman spectroscopy (SERS) platform with patterned printing of plasmonic nanoparticles was constructed for the on-site quick testing of illegal drugs in urine. The filter paper was first coated with a layer of positive-charged chitosan, so as to reduce its roughness by filling the holes of the cellulose matrix and enhance the adhesion of negative-charged silver ink. Subsequently, hydrophobic modification was performed based on the binary silylation reaction, which could obviously improve the sensitivity of the paper-based SERS substrate by concentrating the amount of analyte. Meanwhile, SERS-active silver ink was fabricated and further printed on the surface of the above modified paper with custom-designed pattern (3 × 6). The performance of this SERS platform was assessed by using crystal violet (CV) as a model tag, and the obtained results proved it possesses excellent sensitivity and reproducibility, in which the relative standard deviation (RSD) dropped remarkably. More importantly, as a proof of concept, rapid detection of standard methylamphetamine (MAMP), one of the most widely abused drugs, was achieved with a limit of detection (LOD) of 1.43 ppb using a portable Raman spectrometer. And it also had a good capability in human urine sample detection, with a correlation index (R2) up to 0.9927. This optimized paper-based SERS platform was easily manufactured, cheap, and portable, providing a new strategy for the on-site detection of illicit drugs.

Occurrence and Ecological Risk Assessment of Highly Toxic Halogenated Byproducts during Chlorination Decolorization of Textile Printing and Dyeing Wastewater.

Textile printing and dyeing wastewater is a substantial source of highly toxic halogenated pollutants because of the chlorination decolorization. However, information on the occurrence and fate of the highly toxic halogenated byproducts, which are produced by chlorination decolorization of the textile printing and dyeing wastewater, is very limited. In this study, the occurrence of six categories of halogenated byproducts (haloacetic acids (HAAs), haloacetonitriles (HANs), N-nitrosamines (NAs), trihalomethanes, halogenated ketones, and halonitromethanes) was investigated along the full-scale treatment processes of textile printing and dyeing wastewater treatment plants. Furthermore, the ecological risk of the halogenated byproducts was evaluated. The results showed that the total concentration of halogenated byproducts increased significantly after chlorination. Large amounts of HAAs (average 122.1 µg/L), HANs (average 80.9 µg/L), THMs (average 48.3 µg/L), and NAs (average 2314.3 ng/L) were found in the chlorinated textile wastewater, and the results showed that the generations of HANs and NAs were positively correlated with the BIX and ß/α index, indicating that the HANs and NAs might form from the microbial metabolites. In addition, HAAs and HANs exhibited high ecological risk quotients (>1), suggesting their high potential ecological risk. The results also demonstrated that most halogenated byproducts could be effectively removed by reverse osmosis treatment processes except NAs, with a lower removal rate of 18%. This study is believed to provide an important theoretical basis for controlling and reducing the ecological risks of halogenated byproducts in textile printing and dyeing wastewater effluents.

Recent advances in photoresponsive printing inks for security encoding applications.

Counterfeiting of banknotes, important documents, and branded goods continues to be a major worldwide problem for governments, businesses, and consumers. This problem has serious financial, security, and health implications. Due to their stability for printing on various substrates, the photochromic anticounterfeiting inks have received important interest. There have been various photochromic agents, such as polymer nanoparticles, quantum and carbon dots, and organic and inorganic fluorophores and luminophores, which have been broadly used for antiforging applications. In comparison to organic agents, inorganic photochromic materials have better stability under reversible/long-term light illumination. Recently, the remarkable optical characteristics and chemical stability of photoluminescent and photochromic agents have led to their extensive usage anticounterfeiting products. There have been also several strategies to tackle the rising problem of counterfeiting. Both of solvent-based and water-based inks have been developed for security encoding purposes. Additionally, the printing methods, including screen printing, labeling, stamping, inkjet printing, and handwriting, that have been used to apply anticounterfeiting inks onto various surfaces are discussed. The limitations of photoluminescent and photochromic agents and the potential for their future preparation to combat counterfeiting were discussed. This review would benefit academic researchers and industrial developers who are interested in the area of security printing.

Development of strontium aluminate-printed nonwoven fabric from recycled cotton cellulose for smart wearable photochromic applications.

Smart photochromic and fluorescent textile refers to garments that alter their colorimetric properties in response to external light stimulus. Cotton fibers have been reported as a main resource for many textile and non-textile industries, such as automobiles, medical devices, and furniture applications. Cotton is a natural fiber that is distinguished with breathability, softness, cheapness, and highly absorbent. However, there have been growing demands to find other resources for cotton textiles at high quality and low cost for various applications, such as sensor for harmful ultraviolet radiation. Herein, we present a novel method toward luminescent and photochromic nonwoven textiles from recycled cotton waste. Using the screen-printing technology, a cotton fabric that is both photochromic and fluorescent was developed using aqueous inorganic phosphor nanoparticles (10-18 nm)-containing printing paste. Both CIE Lab color coordinates and photoluminescence spectra showed that the transparent film printed on the nonwoven fabric develops a reversible green emission (519 nm) under ultraviolet light (365 nm), even at low pigment concentration (2%) in the printing paste. Colorfastness of printed fabrics showed high durability and photostability.

Application of a dual-modality colorimetric analysis method to inkjet printing lateral flow detection of Salmonella typhimurium.

Lateral flow assay (LFA) color signal quantification methods were developed by utilizing both International Commission on Illumination (CIE) LAB (CIELAB) color space and grayscale intensity differences. The CIELAB image processing procedure included calibration, test, control band detection, and color difference calculation, which can minimize the noise from the background. The LFA platform showcases its ability to accurately discern relevant colorimetric signals. The rising occurrence of infectious outbreaks from foodborne pathogens like Salmonella typhimurium presents significant economic, healthcare, and public health risks. The study introduces an aptamer-based lateral flow (ABLF) platform by using inkjet printing for specially detecting S. typhimurium. The ABLF utilized gold-decorated polystyrene microparticles, functionalized with specific S. typhimurium aptamers (Ps-AuNPs-ssDNA). The platform demonstrates a detection limit of 102 CFU mL-1 in buffer solutions and 103 CFU mL-1 in romaine lettuce tests. Furthermore, it sustained performance for over 8 weeks at room temperature. The ABLF platform and analysis methods are expected to effectively resolve the low-sensitivity problems of the former LFA systems and to bridge the gap between lab-scale platforms to market-ready solutions by offering a simple, cost-effective, and consistent approach to detecting foodborne pathogens in real samples.

The Latest Advances in Ink-Based Nanogenerators: From Materials to Applications.

Nanogenerators possess the capability to harvest faint energy from the environment. Among them, thermoelectric (TE), triboelectric, piezoelectric (PE), and moisture-enabled nanogenerators represent promising approaches to micro-nano energy collection. These nanogenerators have seen considerable progress in material optimization and structural design. Printing technology has facilitated the large-scale manufacturing of nanogenerators. Although inks can be compatible with most traditional functional materials, this inevitably leads to a decrease in the electrical performance of the materials, necessitating control over the rheological properties of the inks. Furthermore, printing technology offers increased structural design flexibility. This review provides a comprehensive framework for ink-based nanogenerators, encompassing ink material optimization and device structural design, including improvements in ink performance, control of rheological properties, and efficient energy harvesting structures. Additionally, it highlights ink-based nanogenerators that incorporate textile technology and hybrid energy technologies, reviewing their latest advancements in energy collection and self-powered sensing. The discussion also addresses the main challenges faced and future directions for development.

Pharmaceutical applications and requirements of resins for printing by digital light processing (DLP).

The digital light processing (DLP) printer has proven to be effective in biomedical and pharmaceutical applications, as its printing method does not induce shear and a strong temperature on the resin. In addition, the DLP printer has good resolution and print quality, which makes it possible to print complex structures with a customized shape, being used for various purposes ranging from jewelry application to biomedical and pharmaceutical areas. The big disadvantage of DLP is the lack of a biocompatible and non-toxic resin on the market. To overcome this limitation, an ideal resin for biomedical and pharmaceutical use is needed. The resin must have appropriate properties, so that the desired format is printed when with a determined wavelength is applied. Thus, the aim of this work is to bring the basic characteristics of the resins used by this printing method and the minimum requirements to start printing by DLP for pharmaceutical and biomedical applications. The DLP method has proven to be effective in obtaining pharmaceutical devices such as drug delivery systems. Furthermore, this technology allows the printing of devices of ideal size, shape and dosage, providing the patient with personalized treatment.

The reckoning table, the periodoscope and the shaping of modern pregnancy in nineteenth-century print forms.

How did Victorian print forms shape experiences of pregnancy? This article focuses on pregnancy calendars, a form that rose to prominence in nineteenth-century Britain and Europe. Such calendars appeared in tabular as well as circular formats and were printed in books, periodicals and pocketbooks designed for both medical practitioners and fertile women. These calendars shaped the nebulous period of human gestation, giving pregnancy narrative form by dividing it temporally into stages and highlighting key events and medical interventions. In the nineteenth century, these printed pregnancy calendars mediated between women's personal experiences and gestational body time as well as medical management of that time. During this period, such calendars-which included the columnar reckoning table as well as the circular periodoscope-functioned as instruments of both medical control and female agency. Although they did not enable pregnant women to critique the medicalisation of pregnancy, they nevertheless accorded to such women some power in managing their reproductive bodies.

Cross-Scale Topography Achieved by MOPL with Positive Photoresist to Regulate the Cell Behavior.

Cross-scale micro-nano structures play an important role in semiconductors, MEMS, chemistry, and cell biology. Positive photoresist is widely used in lithography due to the advantages of high resolution and environmental friendliness. However, cross-scale micro-nano structures of positive photoresist are difficult to flexibly pattern, and the feature resolution is limited by the optical diffraction. Here, cross-scale patterned micro-nano structures are achieved using the positive photoresist based on the femtosecond laser maskless optical projection lithography (MOPL) technique. The dependence between exposure dose and groove width is comprehensively analyzed, and a feature size of 112 nm is obtained at 110 µW. Furthermore, large-area topography considering cell size is efficiently fabricated by the MOPL technique, which enables the regulation of cell behavior. The proposed protocol of achieving cross-scale structures with the exact size by MOPL of positive photoresist would provide new avenues for potential applications in nanoelectronics and tissue engineering.

Massively Parallel High-Throughput Single-Cell Patterning and Large Biomolecular Delivery in Mammalian Cells Using Light Pulses.

The recent advancements of single-cell analysis have significantly enhanced the ability to understand cellular physiology when compared to bulk cellular analysis. Here a massively parallel single-cell patterning and very large biomolecular delivery is reported. Micro-pillar polydimethyl siloxane stamp with different diameters (40-100 µm with 1 cm × 1 cm patterning area) is fabricated and then imprint distinct proteins and finally pattern single-cell to small clusters of cells depending on the micro-pillar diameters. The maximum patterning efficiency is achieved 99.7% for SiHa, 96.75% for L929, and 98.6% for MG63 cells, for the 100 µm micro-pillar stamp. For intracellular delivery of biomolecules into the patterned cells, a titanium micro-dish device is aligned on top of the cells and exposed by infrared light pulses. The platform successfully delivers small to very large biomolecules such as PI dyes (668 Da), dextran 3000 Da, siRNA (20-24 bp), and large size enzymes (464 KDa) in SiHa, L929 and MG63 cells. The delivery efficiency for PI dye, Dextran 3000, siRNA, and enzyme for patterned cells are ≈95 ± 3%, 97 ± 1%, 96 ± 1% and 94 ± 3%, with cell viability of 98 ± 1%. Thus, the platform is compact, robust, easy for printing, and potentially applicable for single-cell therapy and diagnostics.

Magnetic regulation on evaporation behavior of ferrofluid sessile droplets.

Active magnetic regulation is an emerging subject due to the special and programmable wettability of the sessile ferrofluid droplet. The interaction between liquid and externally applied magnetic field gives rise to controllable spreading and thus evaporation. This work reports the experimental and numerical results of the natural evaporation of a ferrofluid droplet under the effect of a nonuniform magnetic field. The evaporation process of droplets is described into two stages in terms of the geometric distortion and the appearance of the deposition pattern. The presence of the magnetic field leads to a transition of droplet drying from the disk shape with a ring to multiple peaks. A numerical model is established to simulate the evaporation process of ferrofluid droplets with the arbitrary Lagrangian-Eulerian method for tracking droplet deformation. The increasing magnetic flux could effectively enlarge the contact radius and enhance the internal flow of the ferrofluid droplet, thus promoting the evaporation process. The numerical results are verified by comparing the droplet geometry deformation with the experimental results. In both the numerical and experimental investigations, the externally applied magnetic field shortens the process of ferrofluid droplet evaporation. The design and optimization of the magnetic field play an important role in regulating ferrofluid droplet evaporation, which in turn facilitates technological advances in industries such as evaporative cooling and inkjet printing.

On-chip erbium-ytterbium-co-doped lithium niobate microdisk laser with an ultralow threshold.

Erbium-ion-doped lithium niobate (LN) microcavity lasers working in the communication band have attracted extensive attention recently. However, their conversion efficiencies and laser thresholds still have significant room to improve. Here, we prepared microdisk cavities based on erbium-ytterbium-co-doped LN thin film by using ultraviolet lithography, argon ion etching, and a chemical-mechanical polishing process. Benefiting from the erbium-ytterbium co-doping-induced gain coefficient improvement, laser emission with an ultralow threshold (∼1 µW) and high conversion efficiency (1.8 × 10-3%) was observed in the fabricated microdisks under a 980-nm-band optical pump. This study provides an effective reference for improving the performance of LN thin-film lasers.

Structurally Dynamic Gelatin-Based Hydrogels with Self-Healing, Shape Memory, and Cytocompatible Properties for 4D Printing.

Three-dimensional (3D) printable hydrogels with a shape memory effect have emerged as a new class of 4D printing materials recently and found wide applications in various fields. However, synergistically endowing such materials with good mechanical strength and biocompatibility for biomedical uses remains challenging. In this study, a series of multiresponsive hydrogels have been prepared through a dynamic covalent imine/Diels-Alder network from biocompatible starting materials of modified gelatin and poly(ethylene glycol)-based polymers. By further secondary crosslinking with a hyperbranched triethoxysilane reagent (HPASi) that contains multiple supramolecular hydrogen bonding, the hydrogels presented a strengthened self-healing and temperature-responsive shape memory effect. With the additional features of superior stretchability (elongation at break up to 523%), good cytocompatibility, and 3D printable properties, these multifunctional hydrogels showed great potential for broad biomedical applications.

Printable organometallic perovskite enables large-area, low-dose X-ray imaging.

Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks. Solution-processed organic-inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors. However, such detectors have not yet been built on thin-film transistor arrays because it has been difficult to prepare thick perovskite films (more than a few hundred micrometres) over large areas (a detector is typically 50 centimetres by 50 centimetres). We report here an all-solution-based (in contrast to conventional vacuum processing) synthetic route to producing printable polycrystalline perovskites with sharply faceted large grains having morphologies and optoelectronic properties comparable to those of single crystals. High sensitivities of up to 11 microcoulombs per air KERMA of milligray per square centimetre (µC mGyair-1 cm-2) are achieved under irradiation with a 100-kilovolt bremsstrahlung source, which are at least one order of magnitude higher than the sensitivities achieved with currently used amorphous selenium or thallium-doped cesium iodide detectors. We demonstrate X-ray imaging in a conventional thin-film transistor substrate by embedding an 830-micrometre-thick perovskite film and an additional two interlayers of polymer/perovskite composites to provide conformal interfaces between perovskite films and electrodes that control dark currents and temporal charge carrier transportation. Such an all-solution-based perovskite detector could enable low-dose X-ray imaging, and could also be used in photoconductive devices for radiation imaging, sensing and energy harvesting.

Reconciling print-size and display-size constraints on reading.

Two fundamental constraints limit the number of characters in text that can be displayed at one time-print size and display size. These dual constraints conflict in two important situations-when people with normal vision read text on small digital displays, and when people with low vision read magnified text. Here, we describe a unified framework for evaluating the joint impact of these constraints on reading performance. We measured reading speed as a function of print size for three digital formats (laptop, tablet, and cellphone) for 30 normally sighted and 10 low-vision participants. Our results showed that a minimum number of characters per line is required to achieve a criterion of 80% of maximum reading speed: 13 characters for normally sighted and eight characters for low-vision readers. This critical number of characters is nearly constant across font and display format. Possible reasons for this required number of characters are discussed. Combining these character count constraints with the requirements for adequate print size reveals that an individual's use of a small digital display or the need for magnified print can shrink or entirely eliminate the range of print size necessary for achieving maximum reading speed.

Fabric-Based Electrochemical Glucose Sensor with Integrated Millifluidic Path from a Hydrophobic Batik Wax.

In recent years, measuring and monitoring analyte concentrations continuously, frequently, and periodically has been a vital necessity for certain individuals. We developed a cotton-based millifluidic fabric-based electrochemical device (mFED) to monitor glucose continuously and evaluate the effects of mechanical deformation on the device's electrochemical performance. The mFED was fabricated using stencil printing (thick film method) for patterning the electrodes and wax-patterning to make the reaction zone. The analytical performance of the device was carried out using the chronoamperometry method at a detection potential of -0.2 V. The mFED has a linear working range of 0-20 mM of glucose, with LOD and LOQ of 0.98 mM and 3.26 mM. The 3D mFED shows the potential to be integrated as a wearable sensor that can continuously measure glucose under mechanical deformation.

Surfing Scanning Probe Nanolithography at Meters Per Second.

Scanning probe lithography (SPL) as a maskless approach with a low tool price can pattern a variety of materials at a nanometer or even atomic resolution. However, the throughput of conventional SPLs is extremely low due to their limited scanning speeds. Here, we report a high-speed, probe-based method to continuously pattern the substrate surface at a linear velocity of meters per second. We demonstrated direct writings of nanoscale patterns by using ultrafast electron-induced deposition inside a nanoscale flow at a patterning frequency of 20 MHz. The fast scan motion of the writing probe is precisely controlled by using self-adaptive hydro- and aerodynamics functions of a patterning head. The microscale electro-hydrodynamic ejection and microfluid channels are used to deliver the precursor at high scanning speeds. One patterning head can carry parallel probes to further enhance the patterning throughput. This low-cost, maskless patterning method opens new avenues to develop high-throughput nanomanufacturing techniques.