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Directed evolution has become an important method to unleash the latent potential of enzymes to make them uniquely suited for human purposes. However, the need for a large reagent volume and sophisticated instrumentation hampers its broad implementation. In an attempt to address this problem, here we report a paper-based high-throughput screening approach that should find broad application in generating desired enzymes. As an example case, the dehalogenation reaction of the halohydrin dehalogenase was adopted for assay development. In addition to visual detection, quantitative measurements were performed by measuring the color intensity of an image that was photographed by a smartphone and processed using ImageJ free software. The proposed method was first validated using a gold standard method and then applied to mutagenesis library screening with reduced consumption of reagents (i.e., ≤ 10 μl per assay) and a shorter assay time. We identified two active mutants (P135A and G137A) with improved activities toward four tested substrates. The assay not only consumes less reagents but also eliminates the need for expensive instrumentation. The proposed method demonstrates the potential of paper-based whole-cell screening coupled with digital image colorimetry as a promising approach for the discovery of industrially important enzymes.Key Points• A frugal method was developed for directed enzyme evolution.• Mutagenesis libraries were successfully screened on a paper platform.• Smartphone imaging was efficiently used to measure enzyme activities.

This review summarizes main advances achieved by Russian researchers in the synthesis and characterization of semi-synthetic antibiotics of a new generation in the period from 2004 to 2019. The following classes of compounds are considered as the basis for modification: polycyclic antibacterial glycopeptides of the vancomycin group, classical macrolides, antifungal polyene macrolides, the antitumour antibiotic olivomycin A, antitumour anthracyclines and broad-spectrum antibiotics, in particular, oligomycin A, heliomycin and some other. Main trends in the design of modern anti-infective and antitumour agents over this period are considered in relation to original natural antibiotics, which have been independently discovered by Russian researchers. It is shown that a new type of hybrid structures can, in principle, be synthesized based on glycopeptides, macrolides and other antibiotics, including heterodimers containing a new benzoxaborole pharmacophore. The review addresses the influence of the length of the spacer between two antibiotic molecules on the biological activity of hybrid structures. A combination of genetic engineering techniques and methods of organic synthesis is shown to be useful for the design of new potent antifungal antibiotics based on polyenes of the amphotericin B group. Many new semi-synthetic analogues exhibit important biological properties, such as a broad spectrum of activity and low toxicity. Emphasis is given to certain aspects related to investigation of a broad range of biological activity and mechanisms of action of new derivatives. The bibliography includes 101 references.

The greatest challenge for European drug policies is how to effectively respond to the dynamic and constantly changing market for new psychoactive substances (NPS). Even small modifications in the chemical structure of substances often allow circumventing existing laws. Also in prison, the consumption of NPS is rising and there is growing evidence that NPS are responsible for a large share of drug-related problems. Ion mobility spectrometry (IMS) is the technique of choice for trace analysis of illicit drugs or explosives at security points, for example airports. Currently, databases of the reduced mobility (K0 ) values are limited to classical drugs and should be completed with data of emerging NPS. In this article, K0 values, LODs (0.7-3.6 ng) and drift times of 25 synthetic cannabinoids were evaluated. The data were added to existing databases of IMS which were then applied for fast screening in prison. The detection capability of the portable IMS technique was evaluated by the determination of intra-day (0.089%) and inter-day precision (0.004% to 0.14%), systematic error (0.19%), and separation capability for structurally related NPS. The applicability of the methodology was demonstrated by the successful analysis of 12 different pieces of paper impregnated with synthetic cannabinoids, 7 different cosmetics, and 5 food samples (liquids), spiked with a mixture of narcotic drugs and a synthetic cannabinoid. In addition, 14 herbal mixtures and 36 different casework samples from prisons were analyzed provided by the State Office of Criminal Investigation Rhineland-Palatinate (Germany).

This paper focuses on one of the most commonly encountered materials in our society, namely paper. Paper is an inherently complex material, yet its use provides for chemical analysis approaches that are elegant in their simplicity of execution. In the first half of the previous century, paper in scientific research was used mainly for filtration and chromatographic separation. While its use decreased with the rise of modern elution chromatography, paper remains a versatile substrate for low-cost analytical tests. Recently, we have seen renewed interest to work with paper in (bio)analytical science, a result of the growing demand for inexpensive, portable analysis. Dried blood spotting, paper microfluidics, and paper spray ionization are areas in which paper is (re)establishing itself as an important material. These research areas all exploit several properties of paper, including stable sample storage, passive fluid movement and manipulation, chromatographic separation/extraction, modifiable surface and/or volume, easily altered shape, easy transport, and low cost. We propose that the real, and to date underexploited, potential of paper lies in utilizing its combined characteristics to add new dimensions to paper-based (bio)chemical analysis, expanding its applicability. This article provides the reader with a short historical perspective on the scientific use of paper and the developments that led to the establishment of the aforementioned research areas. We review important characteristics of paper and place them in a scientific context in this descriptive, yet critical, assessment of the achieved and the achievable in paper-based analysis. The ultimate goal is the exploration of integrative approaches at the interface between the different fields in which paper is or can be used.

Blood is the most intensely studied human biofluid and is used as the main indicator (so-called “gold standard”) of the health status of the individual. Blood is also a very complex fluid, containing a multiplicity of components, including cells and cell fragments (red and white blood cells, platelets), proteins, and many other organic molecules. Laboratory-based blood analysis is a standard procedure that provides a wealth of information about the concentration of key components and enables medical personnel to establish diagnoses and treatments. To date, options for point-of-care (POC) or point-of-use (POU) blood analysis are limited and very low-cost options even more so. One analytical platform that contains the promise to fill this need utilizes paper-based microfluidic devices. This is a research area that has exhibited significant growth in the past few years, primarily because of its simplicity, fundamental low cost, and versatility. This article reviews the basic properties of blood, how these pr...

Coronavirus disease 2019 (COVID-19) outbreak has become a global pandemic. The deleterious effects of coronavirus have prompted the development of diagnostic tools to manage the spread of disease. While conventional technologies such as quantitative real time polymerase chain reaction (qRT-PCR) have been broadly used to detect COVID-19, they are time-consuming, labor-intensive and are unavailable in remote settings. Point-of-care (POC) biosensors, including chip-based and paper-based biosensors are typically low-cost and user-friendly, which offer tremendous potential for rapid medical diagnosis. This mini review article discusses the recent advances in POC biosensors for COVID-19. First, the development of POC biosensors which are made of polydimethylsiloxane (PDMS), papers, and other flexible materials such as textile, film, and carbon nanosheets are reviewed. The advantages of each biosensors along with the commercially available COVID-19 biosensors are highlighted. Lastly, the existing challenges and future perspectives of developing robust POC biosensors to rapidly identify and manage the spread of COVID-19 are briefly discussed.

Applications of electrochemical detection methods in microfluidic paper-based analytical devices (μPADs) has revolutionized the area of point-of-care (POC) testing towards highly sensitive and selective quantification of various (bio)chemical analytes in a miniaturized, low-coat, rapid, and user-friendly manner. Shortly after the initiation, these relatively new modulations of μPADs, named as electrochemical paper-based analytical devices (ePADs), gained widespread popularity within the POC research community thanks to the inherent advantages of both electrochemical sensing and usage of paper as a suitable substrate for POC testing platforms. Even though general aspects of ePADs such as applications and fabrication techniques, have already been reviewed multiple times in the literature, herein, we intend to provide a critical engineering insight into the area of ePADs by focusing particularly on the practical strategies utilized to enhance their analytical performance (i.e. sensitivity), while maintaining the desired simplicity and efficiency intact. Basically, the discussed strategies are driven by considering the parameters potentially affecting the generated electrochemical signal in the ePADs. Some of these parameters include the type of filter paper, electrode fabrication methods, electrode materials, fluid flow patterns, etc. Besides, the limitations and challenges associated with the development of ePADs are discussed, and further insights and directions for future research in this field are proposed.

Although the established ELISA-based sensing platforms have many benefits, the importance of cytokine and cancer biomarkers detection for point-of-care diagnostics has propelled the search for more specific, sensitive, simple, accessible, yet economical sensor. Paper-based biosensor holds promise for future in-situ applications and can provide rapid analysis and data without the need to conduct in a laboratory. Electrochemical detection plays a vital role in interpreting results obtained from qualitative assessment to quantitative determination. In this review, various factors affecting the design of an electrochemical paper-based biosensor are highlighted and discussed in depth. Different detection methods, along with the latest development in utilizing them in cytokine and cancer biomarkers detection, are reviewed. Lastly, the fabrication of portable electrochemical paper-based biosensor is ideal in deliberating positive societal implications in developing countries with limited resources and accessibility to healthcare services. Ministry of Education (MOE) Published version The authors would like to acknowledge the financial support for this work funded by Singapore Ministry of Education Academic Research Fund Tier 1 (MOE-2018-T1-001-004).

Heavy metal pollution has shown great threat to the environment and public health worldwide. Current methods for the detection of heavy metals require expensive instrumentation and laborious operation, which can only be accomplished in centralized laboratories. Various microfluidic paper-based analytical devices have been developed recently as simple, cheap and disposable alternatives to conventional ones for on-site detection of heavy metals. In this review, we first summarize current development of paper-based analytical devices and discuss the selection of paper substrates, methods of device fabrication, and relevant theories in these devices. We then compare and categorize recent reports on detection of heavy metals using paper-based microfluidic devices on the basis of various detection mechanisms, such as colorimetric, fluorescent, and electrochemical methods. To finalize, the future development and trend in this field are discussed.

Paper-based scaffolds support the three-dimensional culture of mammalian cells in tissue-like environments. These Tissue Papers, a name that highlights the use of materials obtained from (plant) tissue to generate newly functioning (human) tissue structures, are a promising analytical tool to quantify cellular responses in physiologically relevant extracellular gradients and coculture architectures. Here, we highlight current examples of Tissue Papers, commonly used methods of analysis, and current measurement challenges.

Detection of pathogens is crucial in food production areas. While it is well established, swabbing as a state-of-the-art sampling method offers several drawbacks with respect to yield, standardization, overall handling, and long-term monitoring. This led us to develop and evaluate a method that is easier to use at a lower cost and that should be at least as sensitive. After evaluating sundry promising materials, we tested text-marking paper stickers for their suitability to take up and release Listeria monocytogenes with their nonsticky paper side over a 14-day time period using quantitative PCR. The recovery rate was similar to that in previous studies using conventional swabs, and we also confirmed the feasibility of pooling besides resilience to cleansing and disinfection. In a proof-of-concept experiment that sampled several locations, such as door handles, the occurrences of L. monocytogenes and Escherichia coli were determined. The results suggest that the presented sticker system might offer a promising cost-effective alternative sampling system with improved handling characteristics. IMPORTANCE As a ubiquitous bacterium, Listeria monocytogenes has a propensity to enter food production areas inadvertently via fomites such as door handles and switches. While the bacterium might not be in direct contact with the food products, knowing the microbial status of the surroundings is essential for risk assessment. Our investigation into a novel quantitative PCR (qPCR)-based sampling system with the highest sensitivity and ability to monitor over long periods of time, yet based on paper, proved to be cost-effective and reasonably convenient to handle.

As a representative colorimetic biosnesor, paper-based LFSA have emerged as a promising and robust tool that can easily and instansly detect the presence of target biological components in food sample. Recently, LFSAs have gained a considerable attention as an alternative method for rapid diagnosis of foodborne pathogens to the conventional culture-based assays such as plate counting and PCR. One major drawback of the current LFSAs for the detection of pathogenic bacteria is the low sensitivity, limiting its practical applications in POCT. Not like many other protein-based biomarkers that are present in nM or pM range, the number of pathogenic bacteria that cause disease can be as low as few CFU/ml. Here, we review current advances in LFSAs for the detection of pathogenic bacteria in terms of chromatic agents and analyte types. Furthermore, recent approaches for signal enhancement and modifications of the LFSA architecture for multiplex detection of pathogenic bacteria are included in this review, together with the advantages and limitations of each techniques. Finally, the technological challenges and future prospect of LFSA-based POCT for the detection of pathogenic bacteria are discussed.

Paper-based lateral-flow assays (LFAs) have achieved considerable commercial success and continue to have a significant impact on medical diagnostics and environmental monitoring. Conventional LFAs are typically performed by examining the color changes in the test bands by naked eye. However, for critical biochemical markers that are present in extremely small amounts in the clinical specimens, this readout method is not quantitative, and does not provide sufficient sensitivity or suitable detection limit for a reliable assay. Diverse technologies for high-sensitivity LFA detection have been developed and commercialization efforts are underway. In this review, we aim to provide a critical and objective overview of the recent progress in high-sensitivity LFA detection technologies, which involve the exploitation of the physical and chemical responses of transducing particles. The features and biomedical applications of the technologies, along with future prospects and challenges, are also discussed.

Viruses cause many infectious diseases and consequently epidemic health threats. Paper based diagnostics and filters can offer attractive options for detecting and deactivating pathogens. However, due to their infectious characteristics, virus detection using paper diagnostics is more challenging compared to the detection of bacteria, enzymes, DNA or antigens. The major objective of this study was to prepare reliable, degradable and low cost paper diagnostics to detect viruses, without using sophisticated optical or microfluidic analytical instruments. T7 bacteriophage was used as a model virus. A paper based sandwich ELISA technique was developed to detect and quantify the T7 phages in solution. The paper based sandwich ELISA detected T7 phage concentrations as low as 100 pfu/mL to as high as 10 9 pfu/mL. The compatibility of paper based sandwich ELISA with the conventional titre count was tested using T7 phage solutions of unknown concentrations. The paper based sandwich ELISA technique is faster and economical compared to the traditional detection techniques. Therefore, with proper calibration and right reagents, and by following the biosafety regulations, the paper based technique can be said to be compatible and economical to the sophisticated laboratory diagnostic techniques applied to detect pathogenic viruses and other microorganisms.

Paper-based devices serve to address many analytical questions both inside and outside of the laboratory setting. For the first time, yeast were used to construct a whole-cell, paper-based biosensor device. This Biologically-based Paper Analytical Device (BioPAD) is sensitive to antibiotics in the tetracycline family, and it could potentially address questions of pharmaceutical quality as well as antibiotic contamination in liquids. Our BioPAD can qualitatively discriminate the presence/absence of doxycycline over a range of 30 – 10,000 μg/mL. In an analysis of a doxycycline dosage form (tablet) commonly used for malaria prophylaxis, BioPADs identified the presence of antibiotic with 92% and 95% sensitivity, evaluated by eye and computer-assisted image analysis respectively, with no false positives by either method. BioPADs were found to remain viable for at least 415 days when stored at 4ºC. This research demonstrates the utility of whole yeast cells in paper-based pharmaceutical testing, and it highlights the potential for the development of yeast-based BioPADs to address a range of qualitative analytical questions, especially in low resource settings.

Transforming plant biomass to biofuel is one of the few solutions that can truly sustain mankind's long-term needs for liquid transportation fuel with minimized environmental impact. However, despite decades of effort, commercial development of biomass-to-biofuel conversion processes is still not an economically viable proposition. Identifying value-added co-products along with the production of biofuel provides a key solution to overcoming this economic barrier. Lignin is the second most abundant component next to cellulose in almost all plant biomass; the emerging biomass refinery industry will inevitably generate an enormous amount of lignin. Development of selective biorefinery lignin-to-bioproducts conversion processes will play a pivotal role in significantly improving the economic feasibility and sustainability of biofuel production from renewable biomass. The urgency and importance of this endeavor has been increasingly recognized in the last few years. This paper reviews state-of-the-art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignin to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield. The potential synergies of integrating new catalysts with commercial delignification chemistries are discussed. We hope the information will build on the existing body of knowledge to provide new insights towards developing practical and commercially viable lignin conversion technologies, enabling sustainable biofuel production from lignocellulosic biomass to be competitive with fossil fuel.

Advanced Oxidation Processes (AOPs) are called to fill the gap between the treatability attained by conventional physico-chemical and biological treatments and the day-to-day more exigent limits fixed by environmental regulations. They are particularly important for the removal of anthropogenic pollutants and for this reason, they have been widely investigated in the last decades and even applied in the treatment of many industrial wastewater flows. However, despite the great development reached, AOPs cannot be considered mature yet and there are many new fields worthy of research. Some of them are going to be briefly introduced in this paper, including hybrid processes, heterogeneous semiconductor photocatalysis, sulphate-radical oxidation and electrochemical advanced oxidation for water/wastewater treatment. Moreover, the use of photoelectrochemical processes for energy production is discussed. The work ends with some perspectives that can be of interest for the ongoing and future research., Los Procesos de Oxidación Avanzada (POAs) están llamados a llenar el vacío entre la tratabilidad alcanzada por los tratamientos físico-químicos y biológicos convencionales y los límites cada día más exigentes fijados por la normativa medioambiental. Son particularmente importantes para la remoción de contaminantes antropogénicos y por esta razón han sido ampliamente investigados en las últimas décadas e incluso aplicados en el tratamiento de muchos flujos de aguas residuales industriales. Sin embargo, a pesar del gran desarrollo alcanzado, los POA aún no pueden considerarse maduros y existen muchos campos nuevos dignos de investigación. Algunos de ellos se presentarán brevemente en este artículo, incluidos los procesos híbridos, la fotocatálisis de semiconductores heterogéneos, la oxidación por radicales de sulfato y la oxidación electroquímica avanzada para el tratamiento de agua/aguas residuales. Además, se discute el uso de procesos fotoelectroquímicos para la producción de energía. El trabajo finaliza con algunas perspectivas que pueden ser de interés para las investigaciones en curso y futuras.

Over the last years, more stringent safety requirements for an increasing number of chemicals across many regulatory fields (e.g. industrial chemicals, pharmaceuticals, food, cosmetics,...) have triggered the need for an efficient screening strategy to prioritize the substances of highest Concern. In this context, alternative methods such as in silica (i.e. computational) techniques gain more and more importance. In the current study, a new prioritization strategy for identifying potentially mutagenic substances was developed based on the combination of multiple (quantitative) structure-activity relationship ((Q)SAR) tools. Non-evaluated substances used in printed paper and board food contact materials (FCM) were selected for a case study. By applying our strategy, 106 out of the 1723 substances were assigned 'high priority' as they were predicted mutagenic by 4 different (Q)SAR models. Information provided within the models allowed to identify 53 substances for which Ames mutagenicity prediction already has in vitro Ames test results. For further prioritization, additional support could be obtained by applying local i.e. specific models, as demonstrated here for aromatic azo compounds, typically found in printed paper and board FCM. The strategy developed here can easily be applied to other groups of chemicals facing the same need for priority ranking. (C) 2017 Elsevier Ltd. All rights reserved.

There is an extensively growing interest in using paper or paper-like substrates for batteries and other energy storage devices. Due to their intrinsic characteristics, paper (or paper-like) batteries show outstanding performance while retaining low cost, multifunctionality, versatility, flexibility and disposability. In this overview, we review recent achievements in paper (or paper-like) batteries as well as their applications. Various types of paper power devices are discussed including electrochemical batteries, biofuel cells, lithium-ion batteries, supercapacitors, and nanogenerators. Further scientific and technological challenges in this field are also discussed.

Lateral flow biosensors are a leading technology in point-of-care diagnostics due to their simplicity, rapidness and low cost. Their primacy in this arena continues through technological breakthroughs such as multiplexing: the detection of more than one biomarker in a single assay. Multiplexing capacity is critical for improving diagnostic efficiency, enhancing the diagnostic precision for specific diseases and reducing diagnostic cost. Here we review, for the first time, the various types and strategies employed for creating multiplexed lateral flow biosensors. These are classified into four main categories in terms of specific application or multiplexing level, namely linear, parameter, spatial and conceptual. We describe the practical applications and implications for each approach and compare their advantages and disadvantages. Importantly, multiplexing is still subject to limitations of the traditional lateral flow biosensor, such as sensitivity and specificity. However, by pushing the limitations of the traditional medium into the multiplex arena, several technological breakthroughs are emerging with novel solutions that further expand the utility of lateral flow biosensing for point-of-care applications.

Xylanases are enzymes with biotechnological relevance in a number of fields, including food, feed, biofuel, and textile industries. Their most significant application is in the paper and pulp industry, where they are used as a biobleaching agent, showing clear economic and environmental advantages over chemical alternatives. Since this process requires high temperatures and alkali media, the identification of thermostable and alkali stable xylanases represents a major biotechnological goal in this field. Moreover, thermostability is a desirable property for many other applications of xylanases. The review makes an overview of xylanase producing microorganisms and their current implementation in paper biobleaching. Future perspectives are analyzed focusing in the efforts carried out to generate thermostable enzymes by means of modern biotechnological tools, including metagenomic analysis, enzyme molecular engineering and nanotechnology. Furthermore, structural and mutagenesis studies have revealed critical sites for stability of xylanases from glycoside hydrolase families GH10 and GH11, which constitute the main classes of these enzymes. The overall conclusions of these works are summarized here and provide relevant information about putative weak spots within xylanase structures to be targeted in future protein engineering approaches.

Using a cellulosic material dating method recently proposed by three of the authors of the present article further applications to real samples are discussed. In the first instance, to wood samples, that is, to a type of sample for which the method was specifically developed but with the samples differing widely in age, and then to textile or paper samples. Of course in the latter two cases the results obtained are still quite preliminary, above all because of the difficulty of procuring certainly dated samples of this type.

Recent developments in molecular breeding and directed evolution have promised great developments in industrial enzymes as demonstrated by exponential improvements in beta-lactamase and green fluorescent protein (GFP). Detection of and screening for improved enzymes are relatively easy if the target enzyme is expressible in a suitable high-throughput screening host and a clearly defined and usable screen or selection is available, as with GFP and beta-lactamase. Fungal cellulases, however, are difficult to measure and have limited expressibility in heterologous hosts. Furthermore, traditional cellulase assays are tedious and time-consuming. Multiple enzyme components, an insoluble substrate, and generally slow reaction rates have plagued cellulase researchers interested in creating cellulase mixtures with increased activities and/or enhanced biochemical properties. Although the International Union of Pure and Applied Chemists standard measure of cellulase activity, the filter paper assay (FPA), can be reproduced in most laboratories with some effort, this method has long been recognized for its complexity and susceptibility to operator error. Our current automated FPA method is based on a Cyberlabs C400 robotics deck equipped with customized incubation, reagent storage, and plate-reading capabilities that allow rapid evaluation of cellulases acting on cellulose and has a maximum throughput of 84 enzyme samples per day when performing the automated FPA.

The wide use of antibiotics in aquaculture has led to the emergence of resistant microbial species. It should be avoided/minimized by controlling the amount of drug employed in fish farming. For this purpose, the present work proposes test-strip papers aiming at the detection/semi-quantitative determination of organic drugs by visual comparison of color changes, in a similar analytical procedure to that of pH monitoring by universal pH paper. This is done by establishing suitable chemical changes upon cellulose, attributing the paper the ability to react with the organic drug and to produce a color change. Quantitative data is also enabled by taking a picture and applying a suitable mathematical treatment to the color coordinates given by the HSL system used by windows. As proof of concept, this approach was applied to oxytetracycline (OXY), one of the antibiotics frequently used in aquaculture. A bottom-up modification of paper was established, starting by the reaction of the glucose moieties on the paper with 3-triethoxysilylpropylamine (APTES). The so-formed amine layer allowed binding to a metal ion by coordination chemistry, while the metal ion reacted after with the drug to produce a colored compound. The most suitable metals to carry out such modification were selected by bulk studies, and the several stages of the paper modification were optimized to produce an intense color change against the concentration of the drug. The paper strips were applied to the analysis of spiked environmental water, allowing a quantitative determination for OXY concentrations as low as 30 ng/mL. In general, this work provided a simple, method to screen and discriminate tetracycline drugs, in aquaculture, being a promising tool for local, quick and cheap monitoring of drugs.

Microbial pathogens pose serious threats to public health and safety, and results in millions of illnesses and deaths as well as huge economic losses annually. Laborious and expensive pathogen tests often represent a significant hindrance to implementing effective front-line preventative care, particularly in resource-limited regions. Thus, there is a significant need to develop low-cost and easy-to-use methods for pathogen detection. Herein, we present a simple and inexpensive litmus test for bacterial detection. The method takes advantage of a bacteria-specific RNA-cleaving DNAzyme probe as the molecular recognition element and the ability of urease to hydrolyze urea and elevate the pH value of the test solution. By coupling urease to the DNAzyme on magnetic beads, the detection of bacteria is translated into a pH increase, which can be readily detected using a litmus dye or pH paper. The simplicity, low cost, and broad adaptability make this litmus test attractive for field applications, particularly in the developing world.

Paper is predominantly composed of cellulose fibers that have an inherent ability to wick fluids by capillary action; it provides an interesting diagnostic platform that is inexpensive, easily obtained, and eco-friendly. Paper has been used in various types of biologically relevant applications including paper-based molecular assays, paper-based ELISA (P-ELISA), paper-based nucleic acid assays, and paper-based cell assays. Based on recent successes with the use of paper as a platform, we contend that paper is not only very suitable for diagnostics but could provide a more advantageous platform than current plastics-based platforms for drug discovery, and would be useful for accomplishing in vitro pre-compound screening steps while offering a possible solution to several economic obstacles inherent in the pharmaceutical industry.

Recent advances in electrochemical analysis on filter paper exemplify the versatility of this substrate for high performance testing. Its low-cost, light-weight, and environmentally friendly properties make it particularly attractive for applications in addressing health and environmental safety needs in low-resource settings and developing countries. However, the main drawback to sensitive electrochemical testing is the use of a potentiostat, a bench-top instrument that is extremely expensive, thereby negating the some of the benefits of paper-based devices. Hence there is a need to develop paper-devices for use with handheld, portable device readers that can extract quantitative readouts. In this study, we developed a method to use micro-paper electrochemical devices, or µPEDs, with a glucose meter, which are used for personal monitoring of blood glucose levels. Ethanol was chosen as a model target analyte due to its importance in the global issue of road safety. µPEDs were simple in design and could be tested with a potentiostat. We observed that inclusion of the stabilizer trehalose was critical to preparing µPEDs for later analysis. In addition, an NAD+-dependent enzyme was used to impart selectivity to the biosensor, which also represents a class of enzymes with targets relevant to the health and food industry.

Foodborne illnesses occur in both industrialized and developing countries, and may be increasing due to rapidly evolving food production practices. Yet some primary tools used to assess food safety are decades, if not centuries, old. To improve the time to result for food safety assessment a sensitive flow cytometer based system to detect microbial contamination was developed. By eliminating background fluorescence and improving signal to noise the assays accurately measure bacterial load or specifically identify pathogens. These assays provide results in minutes or, if sensitivity to one cell in a complex matrix is required, after several hours enrichment. Conventional assessments of food safety require 48 to 56 hours. The assays described within are linear over 5 orders of magnitude with results identical to culture plates, and report live and dead microorganisms. This system offers a powerful approach to real-time assessment of food safety, useful for industry self-monitoring and regulatory inspection.

This editorial discusses the expanding role of paper as a platform on which to build new point-of-care assays, particularly those intended for use in resource-limited settings. Successful diagnostics for use in these environments require a low-cost platform (possibly paper) as well as new assay strategies, reagents and materials for achieving selectivity and sensitivity. Paper provides a common platform for bringing these components together and serves as a low-cost medium for prototyping new point-of-care assays.

Plant cell walls consist largely of cellulose, non-cellulosic polysaccharides and lignin. Concerted attempts are underway to convert wall polysaccharides from crop plant residues into renewable transport fuels and other valuable products, and to exploit the dietary benefits of cereal grain wall polysaccharides in human health. Attempts to improve plant performance for these applications have involved the manipulation of the levels and structures of wall components. Some successes in altering non-cellulosic polysaccharides has been achieved, but it would appear that drastic changes in cellulose are more difficult to engineer. Nevertheless, future prospects for both genetically modified (GM) and non-GM technologies to modify plant cell wall composition and structure remain bright, and will undoubtedly find applications beyond the current focus on human health and biofuel production.

Chemical fingerprinting methodology is an approach for quality assessment and control of herbal medicines and related products based on the holistic chemical profile obtained by various analytical techniques. This study demonstrates the first application of paper spray mass spectrometry (PS-MS) as a chemical fingerprinting methodology for tracing the origins, establishing the authenticity, and assessing the overall quality of a famous herbal product, Bansha herbal tea (BHT). A negative ion PS-MS spectrum yielded the best chemical profiling information and was most appropriate for fingerprint analysis of BHT. In addition to the identification of active ingredients, various compounds present in BHT were simultaneously detected without any sample pretreatment and chromatographic separation, providing valuable information for the quality assessment and control of this herbal product. According to the principal component analysis of the PS-MS fingerprints, two sources of commercially available BHT products made by different manufacturers were easily differentiated. Qualified and expired products from the two manufacturers were also successfully distinguished, and the consistency of the quality between the manufacturers was assessed. Our experimental data demonstrated that the PS-MS chemical fingerprinting is a simple, rapid, and robust methodology for pharmaceutical analysis, with promising prospects for quality assessment and control of herbal medicines and related products with high-throughput.

Research in cell biology and the development of translational technologies are driven by competition, public expectations, and regulatory oversight, putting these fields at a critical juncture. Success in these fields is quickly becoming dependent on the ability of researchers to identify and isolate specific cell populations from heterogeneous mixtures accurately and efficiently. Many methods for cell purification have been developed, and each has advantages and disadvantages that must be considered in light of the intended application. Current cell separation strategies make use of surface proteins, genetic expression, and physics to isolate specific cells by phenotypic traits. Cell purification is also dependent on the cellular reagents available for use and the intended application, as these factors may preclude certain mechanisms used in the processes of labeling and sorting cells.

Confirmation of a cholera epidemic is based on bacteriological identification of the agent and requires the sending of samples to a culture laboratory, often in countries with limited resources. Comparison of the use of filter paper with the use of Cary-Blair reference medium for stool transport showed that this simple transport medium is appropriate for the recovery of Vibrio cholerae .

Bioremediation of wastewaters represents an important treatment methodology, especially when examined against the backdrop of ever-stricter legislation that is evolving in order to regulate effluent release into the environment. It has been reported that bioremediation specifically holds promise in solving environmental problems. Crucial questions surrounding the treatment of effluents include: efficiency of the process, economic feasibility, legal requirements, and the mechanisms involved in the remediation process. Of all these issues mentioned, the last requires special attention. This paper investigates these matters and focuses on techniques that are currently employed to determine the efficiency of bioremediation and mechanisms involved therein. The physiological significance of biosorption is also examined, as this subject has not been fully addressed in previous publications.