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Microfluidic paper based analytical devices (μPADs) are simple and cost efficient and can be used everywhere without the need for a high standard laboratory for obtaining a readout. These devices are thus especially suited for the developing world or crisis regions. To fabricate a bioanalytical test, certain biomolecules like proteins or antibodies have to be attached to paper strips. Common immobilization methods often rely on non-covalent, unoriented attachment which leads to reduced bioactivity of the immobilized species. Specific Immobilization of biomolecules on surfaces still poses a great challenge to biochemical research and applications. We propose a method for the specific immobilization of biomolecules on functionalized filter paper using a maskless projection lithography setup. The paper was functionalized either by applying an adhesive protein coating or by covalent attachment of methacrylate groups. Fluorescently labelled biomolecules were attached by exploiting the formation of radical species upon bleaching of the fluorophore. A custom made maskless photo-lithography setup and a low cost approach were used to produce microscale biomolecule greyscale patterns. Protein patterns were visualized by fluorescence, enzyme patterns were tested for bioactivity by substrate conversion with colorimetric readout. This method enables the creation of complex, highly specific bioactive protein patterns and greatly facilitates the production of μPADs.

Electrophoretic display (EPD) has been widely used in e-paper applications because of its flexibility, low power consumption, good sunlight visibility. The commercial success of monochromic EPD has boosted the development of full- color EPD to further satisfy people’s demand for various applications. However, many challenges shall be overcome before commercializing it. In this paper, we will introduce the EPD’s fundamental operation, the design of driving waveform for optimizing the opto-electronic performance, and the strategies for achieving full-color EPD as well as a color EPD prototype fabricated by transfer method.

Research on affordable point-of-care health diagnostics is rapidly advancing1. Colorimetric biosensor applications are typically qualitative, but recently the focus has been shifted to quantitative measurements2,3. Although numerous qualitative point-of-care (POC) health diagnostic devices are available, the challenge exists of developing a quantitative colorimetric array reader system that complies with the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, Deliverable to end-users) principles of the World Health Organization4. This paper presents a battery powered 8-bit tonal resolution colorimetric sensor circuit for paper microfluidic assays using low cost photo-detection circuitry and a low-power LED light source. A colorimetric 3×3-pixel array reader was developed for rural environments where resources and personnel are limited. The device sports an ultralow-power E-ink paper display. The colorimetric device includes integrated GPS functionality and EEPROM memory to log measurements with geo-tags for possible analysis of regional trends. The device competes with colour intensity measurement techniques using smartphone cameras, but proves to be a cheaper solution, compensating for the typical performance variations between cameras of different brands of smartphones. Inexpensive methods for quantifying bacterial assays have been shown using desktop scanners, which are not portable, and cameras, which suffer severely from changes in ambient light in different environments. Promising colorimetric detection results have been demonstrated using devices such as video cameras5, digital colour analysers6, flatbed scanners7 or custom portable readers8. The major drawback of most of these methods is the need for specialized instrumentation and for image analysis on a computer.

Conservation of cultural heritage treasures is the most important issue for transferring knowledge to the public through the next generation of students, academics, and researchers. Although this century is authenticating e-books and information by means of electronic text, still historical manuscripts as content as well as objects are the main original recourses of keeping a record of this transformation. The current work focuses on cleaning paper samples by the application of pulsed light, which is interventional. Experiments carried out using paper samples that are artificially colonized with Ulocladium chartarum. Paper is treated by Nd:YAG laser light. The available wavelength is 1064 nm, at various fluences, repetition rates and number of pulses. Two types of paper are stained with fungi colonies, which grow on substrates of clean paper, as well as on paper with ink text. The first type of paper is Whatman No.1056, which is closer to pure cellulose. The second type of paper is a page of a cultural heritage book published in 1926. Cleaning is performed using laser irradiation, thus defining the damage threshold of each sample. The treatment on paper Watman showed a yellowing, especially on areas with high concentration of fungi. The second sample was more durable to the exposure, performing the best results at higher fluences. Eventually, the paper samples are characterized, with optical microscopy and SEM/EDX analyses, prior to and after cleaning.

This paper describes pattern processing and recognition for a user interface with real papers rather than display, keyboard and mouse for document editing. We call this UI (User Interface) as 'Paper based User Interface.' In order to realize this UI, we need a technology to detect and recognize correction marks written on printouts of documents. This paper presents a new technology that detects handwritten marks without restricting the way to write correction marks or forcing the users to use a pen of a specific color and a specific scanner. At first, documents are printed out with dotted characters, and they can be easily dropped out to detect correction marks and also they can be easily emphasized to detect where each correction mark is applied. We made a prototype on a PC and verified that the method can extract almost all correction marks correctly.

In the production of pigment-coated paper or paperboard, the method and rate of drying of the coating will significantly influence the print quality of the finished product. Improper drying during initial st sages can cause binder migration that leads to its non-uniform concentration on the surface of the coating. Such effect causes print mottle, and is a primary reason for poor print quality. The location at which binder immobilization has occurred is called the Gel Point. An on-line fiber optic sensor system has been applied to continuously monitor the location of the Gel Point. Each sensor consists of a light source, an optical fiber for delivering the radiation, two optical fibers for diffuse and specular radiation monitoring and two detectors. The ratio R between diffuse and specular signals indicates coating conditions. A system description and experimental results are presented. The Gel Point measurement system has show that is provides a sensitive measurement of the gel point location, as it is affected by machine speed, coat weight, incoming substrate moisture levels and drying energy and can predict print mottle. This provides the paper maker with a completely independent method for monitoring the coating drying process.

This Conference Presentation was recorded at SPIE Photonics West 2017 held in San Francisco, California, United States.

We built a hyperspectral imaging apparatus using middle-infrared light of 8–14 μm, which has a strong ability to identify organic materials, and attempted visualization of the distribution of organic materials that could not be identified by a naked eye. For this purpose, we utilized a low-cost bolometer camera (Nippon Avionics co., ltd. C100V, Japan) for its easy availability rather than an expensive mercury cadmium telluride (MCT) array sensor. To compensate for the low sensitivity of this bolometer, we adopted a Fourier-type spectroscopic system (Aoi Electronics co. ltd., Japan) using an imaging interferometer devised by the Kagawa University, Japan; this interferometer has higher light-utilization efficiency than Michelson interferometers, which are used in popular interferometry techniques. In this study, 4 types of adhesives, 9 types of varnishes and more than 50 types of inks were put on Al plates of size 10 cm × 10 cm and were used as samples. Glossy paper for printing photos with an inkjet printer was also used as a sample. A 300 °C black body of size 15 cm × 15 cm was used as a light source. Spectra of 320 × 240 points were measured at a wavelength resolution of approximately 9 cm−1. The mirror was scanned only once. The measurement time was approximately 30 s. Hyperspectral images of adhesives, varnishes and inks on Al plate and paper were successfully measured. Spectra over a 5 × 5-pixel neighborhoods were averaged, and the averaged spectra were compared with those measured by a commercially available Fourier transform infrared (FTIR) spectroscopy. The averaged and measured spectra had absorption peaks at the same wavelengths. Furthermore, by analyzing the measured spectra, the distribution of substances invisible to the naked eye was visualized. Our results show that if low-absorbance organic materials are put on a high-reflectance surface such as an Al plate, the middle-infrared hyperspectral imaging could be measured using a bolometer. Additionally, hyperspectral imaging of high-reflectance paper, such as glossy paper, could also be measured. Because a bolometer camera is much cheaper than an MCT array, hyperspectral imaging with such a camera has many potential applications. Moreover, an imaging interferometer, with its high efficiency of light utilization, is very suitable for the purpose.

Given monochromatic infrared LED (light emitting diode) device best modulation current, frequency, distance to reach its maximum output power and improve the measuring accuracy of quantifier. Design a wavelength of 2.12 μm, 1.89 μm monochromatic infrared emissions and detection optical path, two monochromatic infrared lights which the photo source sends out after transmits the analyte across the same point to achieve the same point detection and improve the accuracy of the measurement. After the paper samples basis weight have carried out nondestructive testing, which was improved from the aspects of structure. By using the light source, halogen tungsten lamp, filter wheel, electrical equipment can be saved, and it can simplify the measuring system. The experimental results show that when measuring the thickness of the paper in the range, the relative error is within 1%.

This paper will review the origins and state of the art in paper-based electronics, suggesting the stage is set for future promising applications. Current interest in paper-based electronics can trace its roots to recent developments in paper-based microfluidics. With a need to improve the reliability and sensitivity of paperbased microfluidics for certain tasks, there were natural efforts to begin embedding sensing electrodes into microfluidic devices. Recognizing the general benefits of paper as an advanced material (e.g., its environmental friendliness, bendable nature, and low cost), efforts in paper-based electronics also began to take a life of their own with demonstrations of transistors, batteries and devices for energy storage, energy harvesting, sensors to improve situational awareness, acoustics, and displays. The state-of-the-art paper-based electronic devices have benefited and will continue to profit from technologies for printing and transferring electronic functionality onto the surfaces of paper-based substrates. Nonetheless, the authors suggest that many future promising applications will go beyond using paper as a carrier/substrate for electronic components to explore tuning of the electrical, mechanical, and chemical properties of the paper itself. With these technical advances, paper-based electronics will move closer to economically viable killer applications.

Plasmonic biosensors hold enormous potential for the development of low-cost, label-free, point-of-care biodiagnostics. However, two major challenges need to be overcome to reap the benefits of this class of biosensors: (i) state-of-the-art plasmonic biosensors either offer limited sensitivity or are impractical for real-world applications due to their poor stability and excessive cost; (ii) these biosensors rely on natural antibodies, which are high-cost and impose severe limitations in handling, storage and device integration. We demonstrate that a common filter paper can be transformed into a plasmonic sensing platform for highly sensitive and selective detection of trace levels of chemical and biological analytes. We also demonstrate that short peptides as biorecognition elements compared to larger antibodies as target capture agents offer several advantages. Using a bioplasmonic paper device, we demonstrate the selective and sensitive detection of the cardiac biomarker troponin I. The smaller sized peptide provides higher sensitivity and a lower detection limit using a bioplasmonic paper device. Furthermore, the excellent shelf-life and thermal stability of peptide-based plasmonic biosensors, which precludes the need for special storage conditions, makes it ideal for use in resource-limited settings. We also demonstrate plasmonic biosensors based on artificial antibodies by molecularly imprinting the plasmonic nanotransducers. Apart from significantly lowering the cost, these developments are critical for translating plasmonic sensors to point-of-care and resource-limited settings.

In this work we present a promising method for fabrication of conductive tracks on paper based substrates by laser assisted reduction of Graphene Oxide (GO). Printed electronics on paper based substrates is be coming more popular due to lower cost and recyclability. Fabrication of conductive tracks is of great importance where metal, carbon and polymer inks are commonly used. An emerging option is reduced graphene oxide (r-GO), which can be a good conductor. Here we have evaluated reduction of GO by using a 532 nm laser source, showing promising results with a decrease of sheet resistance from >100 M Ω/Sqr for unreduced GO down to 126 Ω/Sqr. without any observable damage to the paper substrates.

Advancement of distributed piezo-electret sensors and actuators facilitates various smart systems development, which include paper speakers, opto-piezo/electret bio-chips, etc. The array-based loudspeaker system possess several advantages over conventional coil speakers, such as light-weightness, flexibility, low power consumption, directivity, etc. With the understanding that the performance of the large-area piezo-electret loudspeakers or even the microfluidic biochip transport behavior could be tailored by changing their dynamic behaviors, a full-field real-time high-resolution non-contact metrology system was developed. In this paper, influence of the resonance modes and the transient vibrations of an arraybased loudspeaker system on the acoustic effect were measured by using a real-time projection moire metrology system and microphones. To make the paper speaker even more versatile, we combine the photosensitive material TiOPc into the original electret loudspeaker. The vibration of this newly developed opto-electret loudspeaker could be manipulated by illuminating different light-intensity patterns. Trying to facilitate the tailoring process of the opto-electret loudspeaker, projection moire was adopted to measure its vibration. By recording the projected fringes which are modulated by the contours of the testing sample, the phase unwrapping algorithm can give us a continuous phase distribution which is proportional to the object height variations. With the aid of the projection moire metrology system, the vibrations associated with each distinctive light pattern could be characterized. Therefore, we expect that the overall acoustic performance could be improved by finding the suitable illuminating patterns. In this manuscript, the system performance of the projection moire and the optoelectret paper speakers were cross-examined and verified by the experimental results obtained.

The paper industry has long had a need to better understand and control its papermaking process upstream, specifically at the wet end in the forming section of a paper machine. A vision-based system is under development that addresses this need by automatically measuring and interpreting the pertinent paper web parameters at the wet end in real time. The wet-end characterization of the paper web by a vision system involves a four-dimensional measurement of the slurry in real time. These measurements include the two-dimensional spatial information, the intensity profile, and the depth profile. This paper describes the real-time depth profile measurement system for the high-speed moving slurry. A laser line-based measurement method is used with a high-speed programmable camera to directly measure slurry height. The camera is programmed with a profile algorithm, producing depth data at fast sampling rates. Analysis and experimentation have been conducted to optimize the system for the characteristics of the slurry and laser line image. On-line experimental results are presented.

Ink jet printability is rapidly becoming a requirement for all multipurpose office papers. These papers must have an optimized balance of properties so they can perform equally well under various printing methods such as xerography, ink jet, and thermal imaging. The office paper of today truly must be a multipurpose copy paper capable of providing good toner adhesion as well as controlled absorption of aqueous ink jet solutions. The demand for ink jet paper is increasing rapidly. The global market for cut-size ink jet papers will expand to nearly 1.4 million tons by the year 2000. By that time the global market for all cut-size multipurpose plain printing papers will grow to nearly twenty million tons. The ink jet printing process places a large volume of aqueous ink on the surface of a substrate. The manner in which the substrate handles that volume of ink determines in large part the quality of the print. Multipurpose office papers are composed chiefly of cellulose fibers, inorganic fillers, and chemical additives. All of these components affect the quality of the sheet as an ink jet substrate. The particle morphology, surface area, and surface treatment of PCC fillers affect the ink jet printability of multipurpose office papers. This paper focuses on results from pilot paper machine and commercial trials performed in an effort to turn 'plain' office papers into high quality multipurpose papers capable of meeting or exceeding ink jet print quality specifications.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Paper makers use many different synthetic and natural chemical additives for a variety of different reasons during the wet formation process. They are used to influence the efficiency of the formation process or to impart specific sheet properties. They are usually added (with the exception of pigments) at a level of around 0-5% by weight of the other components of the furnish and, because of their relatively high cost, they often represent a significant proportion of the total raw material costs - particularly for recycled grades where the fibre costs may be very low. When it is necessary to modify bulk sheet properties, as in the control of aqueous fluid penetration (internal sizing), the chemicals have to be added to the wet fibre suspension so that they become well distributed throughout the z-direction of the sheet. Chemicals which are added as a surface treatment to the dry sheet are usually only able to influence surface properties.

The composition of photographic color negative papers is reviewed. Information is presented on the potential detrimental effect of the polyethylene resin-coated (RC) paper support on the thermal stability of the silver halide element. Evidence is provided for the major role that the pH of the dry paper stock has in this effect. A mechanism for the detrimental photographic performance involving both the RC and the paper stock is proposed.

From the chemical point of view paper coatings are mainly polymer dispersions. Polymer dispersions are constituted in multitude fields, for example as dispersion coatings or adhesives. As far as no additional treatment is done, polymer materials as well as polymer agents contain non polymer, volatile organic components that may arise from: (1) incomplete polymerization of the applied monomers, (2) primary materials containing non polymerizable components, (3) undesirable side reactions during the synthesis. Requirements for the removal of volatile substances from polymer dispersion are given by several reasons: (1) low molecular substances deteriorate the product characteristics (viscosity, thermal stability and others), (2) in order to comply with legislative standards, volatile organic compounds have to be removed from dispersions, especially when applied to large surfaces (e.g. in surface refining in paper and leather industries as well as on coating). The removal of volatile organic compounds (deodorization) can be realized in continuous or discontinuous processes. In contrast to highly developed process technology, the process itself is not well understood, especially mass transport phenomena between the gas phase and the aqueous polymer dispersion are insufficiently and controversially discussed in the literature. Two processes, their advantages and disadvantages and the description by mathematical- mechanistic models are presented in this paper.

Uncontrolled growth of bacteria and fungi in the papermaking process adversely affects machine runability. How this growth influences factors in the finished sheet and sheet print properties is often overlooked, even though it can have a profound effect on printing characteristics. Many of the materials used in making paper coatings are excellent microbial nutrients. In addition to being nutrients, these compounds are critical to performance. For example, coatings made of poorly preserved clays can form a surface that has fine scratches caused by microagglomeration of the clay particles. This may be caused by microbial degradation of the dispersants in the clays. This paper explores these issues and discusses steps that can be taken to minimize these problems.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Microfluidic paper-based analytical devices decorated with ZnO nanospherical (nanoSPs) aggregates (ZnO-μPAD) for glucose detection have been fabricated. ZnO nanoSPs were prepared by wet chemical synthesis and integrated on the optimized geometry of ZnO-μPAD has 0.2 and 0.4 mm of channel width and length, respectively. Glucose detection measurements were based on electrochemical and infrared transmission measurements. The glucose concentrations were adjusted as 5, 6.5, and 9 mmol, i.e. typical glucose level for normal, pre-diabetes and diabetes, in a mixture of ringer lactate as simulated biological fluid and red blood cells. ZnO nanoSPs in this study possess an average aggregate size of 160 nm formed by clustered ~ 18 nm crystallite size and ordered porous matrix as well as a surface area of 15 m2·g-1.The separation process of the glucose sample on ZnO-μPAD requires approximately 45 s. The glucose detection results show that both electrochemical-based and FTIR-based measurements perform a linear measurement system (R2 of 0.81 to 0.99) with a relatively high sensitivity. A linearly decreasing impedance spanning from 2.2 – 0.6 Ohm and linearly increasing ΔIR transmission spanning from 3 – 19% are obtained for glucose level ranging from 5 – 9 mmol.

The ESO Telescope Bibliography (telbib; http://telbib.eso.org) is a database of refereed papers published by the ESO users community. It links data in the ESO Science Archive with the published literature, and vice versa. Developed and maintained by the ESO library, telbib also provides insights into the organization’s research output and impact as measured through bibliometric studies. Numerous reports, statistics, and visualizatons derived from telbib help to understand the way in which the user community uses ESO/VLT data in publications. Based on selected use cases, we will showcase recent trends and developments.

A methodology has been developed to digitize images from photographic color paper (reflection prints) and store the spectral information as a function of the three dye density basis functions inherent to the paper film type. The result is a highly accurate digitization of the spectral information at each spatial pixel that can be digitally stored with very little additional storage space over conventional RGB-type methodologies.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

IR monitoring is a basic tool for quality control and predictive maintenance in the paper industry. There are also other possible interests, e.g. measurements of temperature profiles of high speed production lines. The first possibility to use IR for the above mentioned use appears to be applications of glass heat treatment in on line production. At this time there is a lot of interest to be able to measure temperature profiles from a fast moving surface (e.g. in paper machines) with velocities like 10 - 20 m/s. Normal low speed line scanners typically give scanning speed of 50 Hz which in this case means 20 m/s/50 Hz equals 40 cm resolution. The obtained resolution is not normally high enough. To have more accurate vision from the studied surface IR camera line scanning was proposed to be a solution with line scanning frequencies of 8000 Hz which would provide resolution of 20 m/s/8000 Hz equals 0.25 cm between surface points. It is a well-known fact that all undesired frequencies in paper transfer systems disturb the uniform paper drying process which in some cases is the basic reason for low quality coating or even broken paper line. The possibility to detect these drying problems with IR frequency analysis will give a new way to control the paper drying process. With IR analysis it is possible to get information about temperature distributions along the paper track. Using a well established frequency analysis as a tool, the error estimations are obtained. In most cases an open-roll image from paper track is very desirable because there are no existing wide area measurement systems for this purpose. The careful analysis of this new method is given in the manuscript.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The expression 'Plain' paper was coined in the early days of electrophotography to distinguish the capabilities of the new dry toner based photocopying process which did not require a sensitized or special coated paper to produce an image. Currently 'Plain' paper is considered in the electronic printing industry, to be any uncoated paper, usually of the type used in office photocopying applications. It is assumed that all 'Plain' papers are identical or at least equivalent in their properties such that all papers will give equivalent print quality performance. Due to the wide availability and low price of 'Plain' papers, it is also considered desirable by vendors of electronic marking processes, that their technology be capable of producing good image quality on 'Plain' paper. The chemical and physical differences which can occur among 'Plain' papers are discussed with respect to the specific image quality and engine reliability requirements of the major nonimpact electronic marking technologies, including electrophotography and laser printing, electrographic and ionographic processes, thermal transfer and ink jet. Paper properties of interest include, smoothness, surface energy, electrical resistivity, porosity and aqueous and nonaqueous liquid adsorption. Color printing has added additional requirements to paper quality, if good image quality is to be achieved and maintained. Given the apparently conflicting requirements for some of the electronic marking technologies, it will be a challenge to define a single grade of paper which will produce optimum print quality for all electronic printing processes.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Laser ablation offers cleaning method for historical and art works effectively. Difference between ablation threshold of contamination layer and the surface yields to remove contaminants from surface without detriment to historical material. In particular, lasers with ultrashort pulse duration are very convenient for brittle historical papers, fibers of which should be intact after cleaning treatment. Since duration of laser irradiation and material interaction is very short, the possibility of damage to the paper is very low. One of the other crucial issues after paper cleaning treatment is color variation on the surface. Authentic color of the historical paper has to be preserved after the procedure. In this paper, we present results of paper cleaning via femtosecond (fs) laser running at a wavelength of 1030 nm. In the first stage of this experimental study, we determined optimum laser parameters on artificially soiled and aged paper samples, then cleaned a handwritten manuscript with ‘sizing’. In calligraphy, ornamentation and miniature arts, sizing is applied on paper as a protective layer which increases strength of paper and renders it more useful. Papers with sizing have been prevalently used in Islamic or Ottoman culture. We observed that after laser irradiation, artificial soling layer is effectively removed, while original color of the subs-layers did not alter. We used scanning electron microscopy (SEM) to examine fiber integrity, and determined that the sizing layer was not removed when optimized parameters were used, thus the fibers were not damaged.

Rapid and inexpensive virus detection and quantification at the point -of -care is of paramount importance for HIV management in resource -limited settings . Here, we report on an eas y-to-fabricate, cellulose paper -based microchip with printed graphene -modified electrode s for rapid detection of HIV -1 through electrical sensing . We evaluated the effect of electrode material and geometry on the performance of the microchip to detect serially diluted , electrically conductive samples . We evaluated the optimized microchip with HIV -spiked samples . 1. Introduction Effective, rapid , and inexpensive detection of virus es in biological samples at the point -of -care (POC) is an urgent need for infectious disease detection and treatment monitoring in resource -limited settings . Of particular interest is the detection and quantificatio n of Human Immunodeficiency Virus (HIV) in fingerprick volume s of biological samples at the POC for early detection of the disease and treatment monitoring in developing countries . According to UNAIDS , 35.3 million people are HIV infected globally , of whic h 25.0 million of them (equivalent to 70% of total HIV patients) live in sub -Saharan African countries [1]. T he t otal medical expenditure for HIV/AIDS in 20 12 was 18.9 b US $ and it is estimated that the annual expense will reach 22 -24 b US $ by the end of 2015 [1] . Expanding access globally to antiretroviral therapy (A RT) has been highly effective in reducing mortality in developing countries, however, a significant percentage of HIV -infected individuals do not yet receive ART , and those who have access to the treatment may not receive an effective therapy due to limited access to the appropriate treatment monitoring assays [2, 3] . Current rapid HIV tests, including OraQuick HIV test, lack the ability to detect HIV infection in the early stage as they d etect antibodies utilizing the principles of enzyme -linked immunosorbent assay (ELISA) and lateral flow test (LFT) . Further, these tests cannot detect virological failure that is critical for treatment monitoring and diagnosis of ART failure . Antibodies against HIV -1 start to appear after 3 -8 weeks from the initial infection . HIV -infected individuals have the potential to be substantial sources for transmission of the infection at the acute stage, when maximum vir al replication takes place . Although nucle ic acid tests (NAT) provide sensitive and accurate results for HIV detection and viral load measurement, these assays are laboratory -based, expensive, time consuming, and require skilled personnel [3]. Microfluidics has shown great promise in developing diagnostic assays for disease detection and treatment monitoring at the POC [3, 4] . Electrical sensing also provides robust , sensitive, and rapid detection of analytes in biological samples without the need for bulky equipment in optical -based sensing mechanisms [5 -11] . We have previously shown that electrical sensing modalit ies can be integrated with microfluidics to detect viruses in HIV -spiked samples [5, 10] . HIV was captured and isolated from samples off -chip using magnetic beads conjugated with ant i gp -120 antibody , and captured viruses were detected on -chip through electrical sensing of viral lysate . Here, for the first time, we present a cellulose paper -based microchip with printed graphene/silver electrodes for on -chip HIV capture and detection u sing electrical sensing of viral lysate.

Therapeutic drug monitoring (TDM) contributes to safe and effective pharmacotherapy in clinical fields. A simple, rapid, low-cost, and minimally-invasive drug measurement method attracts much interest for point-of-care TDM. Tear fluids can be collected minimally-invasively compared to blood sampling and there is a correlation between a drug concentration in tears and that in bloods. Surface enhanced Raman spectroscopy (SERS) with paper-based substrate is useful for point-of-care TDM owing to inexpensiveness and high-sensitivity. Paper is also a safe tear collection tool. Then we are studying on a paper-based SERS of tear specimen for point-of-care TDM. In this paper, to improve sensitivity in measuring drug concentration in tear fluids, we fabricated a SERS substrate by coating gold nano-rods on a paper substrate and evaluated whether the fabricated substrate can enhance Raman scattering. Sodium phenobarbital (PB), an anti-convulsant agent, was used as a target. In experiment, the fabricated substrate indicated the lower detection limit of PB in a solution than a plain paper substrate. This result showed the potential of the paper based SERS substrate to measure drug concentration in tears simply and inexpensively.

By combining the physical principles behind the nastic plant movements and the rich designs of paper folding art, we propose a new class of multi-functional adaptive structure called fluidic origami cellular structure. The basic elements of this structure are fluid filled origami "cells", made by connecting two compatible Miura-Ori stripes along their crease lines. These cells are assembled seamlessly into a three dimensional topology, and their internal fluid pressure or volume are strategically controlled just like in plants for nastic movements. Because of the unique geometry of the Miura-Ori, the relationships among origami folding, internal fluid properties, and the crease bending are intricate and highly nonlinear. Fluidic origami can exploit such relationships to provide multiple adaptive functions concurrently and effectively. For example, it can achieve actuation or morphing by actively changing the internal fluid volume, and stillness tuning by constraining the fluid volume. Fluidic origami can also be bistable because of the nonlinear correlation between folding and crease material bending, and such bistable character can be altered significantly by fluid pressurization. These functions are natural and essential companions with respect to each other, so that fluidic origami can holistically exhibit many attractive characteristics of plants and deliver rapid and efficient actuation/morphing while maintaining a high structural stillness. The purpose of this paper is to introduce the design and working principles of the fluidic origami, as well as to explore and demonstrate its performance potential.

Carbon nanotube paper (CNP) based multi-functional composite material is an attractive candidate for deicing, flame retardancy, thermal insulation and lighting strike protection due to the excellent conductivity, light weight and thin dimensions. In this article, multi-functional carbon nanotube paper was fabricated successfully by using commercial carbon nanotube. As a deicing composite material, carbon nanotube was used directly without pretreatment in fabricating carbon nanotube paper. The conductivities of the carbon nanotube paper and deicing composite were 77.8S/cm and 64.9S/ respectively. Electrical heating and deicing performance were test by infrared camera with deicing time less than 220s and 450s to melt a certain amount of ice under different ambient condition. CNT was grafted by zirconium (IV) butoxide solution and dimethyl dichlorosilicane to form co-oligomers on the tube surface while oligomers decompose under a certain temperature to develop an inorganic layer of silicon zirconium oxide. The oxidizing temperature of carbon nanotube increases more than 20°C and the weight loss rate decreases 20% than the untreated carbon nanotube. Lightning protection material required high electro conductivity, due to the utmost high current in a short time. Therefore, silver nanoparticles were deposited on the surface of carbon nanotube with the diameter around 100nm. The conductivity increased sharply from 84s/cm to1756s/cm with the mount of 5.9wt% Ag of the modified carbon nanotube paper because the silver nanoparticles deposited on the surface. In addition, the silver modified also can be used as thermal insulation material decreasing the infrared radiation.

As a bio/chemical sensing technique, surface enhanced Raman spectroscopy (SERS) offers sensitivity comparable to that of fluorescence detection while providing highly specific information about the analyte. Although single molecule identification with SERS was demonstrated nearly 20 years ago, today a need exists to develop practical solutions for point‐of‐sample and point‐of‐care SERS systems. Recently, we demonstrated the fabrication of SERS substrates by inkjet printing silver and gold nanostructures onto paper and other microporous membranes. Using these devices, we have been able to achieve detection limits comparable to conventional nanofabricated plasmonic substrates. Furthermore, we leverage the fluidic properties of paper to enhance the performance of the SERS devices while also enabling unprecedented ease of use. Here we report the use of inkjet‐fabricated paper SERS substrates as a detection device for biological macromolecules in an easy‐to‐use format with a low number of steps. The targeted biomarker is specifically detected with SERS through a single step competitive displacement, which dramatically reduces the number of steps as compared to conventional assays. Moreover, we further improve the usability of the assay by incorporating a paper SERS device with a fluidic cartridge format. The wicking nature of the paper sensor eliminates manual sample application steps and is much simpler than the world‐to‐chip interface of microfluidic devices. The introduction of this paper‐based SERS assay is a significant step towards highly sensitive, low‐cost, and, importantly, easy to use multiplexed biological assays.

In this work we have investigated the use of laser sintering of different ink-jet printed nano-particle links (NPIs) on paper substrates. Laser sintering is shown to offer a fast and non-destructive way to produce paper based printed electronics. A continuous wave fiber laser source at 1064 nm is used and evaluated in combination with a galvo-scanning mirror system. A conductivity in order of 2.16 * 107 S/m is reached for the silver NPI structures corresponding to nearly 35 % conductivity compared to that of bulk silver and this is achieved without any observable damage to the paper substrate.

There are two main challenges in producing a robust, paper-based analytical device. The first one is to create a hydrophobic barrier which unlike the commonly used wax barriers does not break if the paper is bent. The second one is the creation of the (bio-)specific sensing layer. For this proteins have to be immobilized without diminishing their activity. We solve both problems using light-based fabrication methods that enable fast, efficient manufacturing of paper-based analytical devices. The first technique relies on silanization by which we create a flexible hydrophobic barrier made of dimethoxydimethylsilane. The second technique demonstrated within this paper uses photobleaching to immobilize proteins by means of maskless projection lithography. Both techniques have been tested on a classical lithography setup using printed toner masks and on a lithography system for maskless lithography. Using these setups we could demonstrate that the proposed manufacturing techniques can be carried out at low costs. The resolution of the paper-based analytical devices obtained with static masks was lower due to the lower mask resolution. Better results were obtained using advanced lithography equipment. By doing so we demonstrated, that our technique enables fabrication of effective hydrophobic boundary layers with a thickness of only 342 μm. Furthermore we showed that flourescine-5-biotin can be immobilized on the non-structured paper and be employed for the detection of streptavidinalkaline phosphatase. By carrying out this assay on a paper-based analytical device which had been structured using the silanization technique we proofed biological compatibility of the suggested patterning technique.

The UK National Quantum Technology Hub in Sensors and Metrology is one of four flagship initiatives in the UK National of Quantum Technology Program. As part of a 20-year vision it translates laboratory demonstrations to deployable practical devices, with game-changing miniaturized components and prototypes that transform the state-of-the-art for quantum sensors and metrology. It brings together experts from the Universities of Birmingham, Glasgow, Nottingham, Southampton, Strathclyde and Sussex, NPL and currently links to over 15 leading international academic institutions and over 70 companies to build the supply chains and routes to market needed to bring 10–1000x improvements in sensing applications. It seeks, and is open to, additional partners for new application development and creates a point of easy open access to the facilities and supply chains that it stimulates or nurtures.

The first thermal paper technology was developed in the 1930s. Since then, thermal recording systems have branched into two main groups, two-component systems and heat-transfer systems. In the 1960s, the leuco dye system was developed by NCR. This type of system has been used mainly in thermal recording systems. The leuco dye system however has some drawbacks such as poor image stability and an artificial texture. In a recent development, a compound with an epoxy functional group was added to the thermal sensitive layer of a leuco dye thermal paper to obtain good stability. A special overcoat layer gives the product the texture of plain paper. In addition to this product, other special thermal papers have been developed, such as two-color thermal paper, IR readable thermal paper, high resolution thermal paper, and translucent thermal paper.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Angle-resolved light scattering (ARLS) was used to investigate the roughness of coatings on glossy paper. Angular spectra were measured for laser light scattered from several glossy paper samples and from uncoated paper. These spectra are compared to those calculated using the Beckmann model of a random surface that is isotropic and rough in two dimensions. Such a surface is characterized by its rms roughness and autocorrelation function, which are determined from surface profiles measured with a stylus instrument. There is very good agreement between the measured and the computed ARLS spectra. The surfaces are too rough to produce a specular beam large enough to provide an accurate value of the rms roughness, but ARLS provides information about the coating roughness when the measured spectra are cornpared to computed ones.