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High per- and polyfluorinated alkyl substance (PFAS) concentrations have been detected in agricultural soils in Southwest Germany. Discharges of PFAS-contaminated paper sludge and compost are suspected to be the cause of the contamination. Perfluorinated carboxylic acids (PFCAs) have been detected also in groundwater, drinking water, and plants in this area. Recently, previously unknown compounds have been identified by high-resolution mass spectrometry (HRMS). Major contaminants were polyfluorinated dialkylated phosphate esters (diPAPs) and N-ethyl perfluorooctane sulfonamide ethanol-based phosphate diester (diSAmPAP). In this study, HRMS screening for PFAS was applied to 14 soil samples from the contaminated area and 14 impregnated paper samples which were from a similar period than the contamination. The paper samples were characterized by diPAPs (from 4:2/6:2 to 12:2/12:2), fluorotelomer mercapto alkyl phosphates (FTMAPs; 6:2/6:2 to 10:2/10:2), and diSAmPAP. In soil samples, diPAPs and their transformation products (TPs) were the major contaminants, but also FTMAPs, diSAmPAP, and their TPs occurred. The distribution patterns of the carbon chain lengths of the precursor PFAS in soil samples were shown to resemble those in paper samples. This supports the hypothesis that paper sludge is a major source of contamination. The presence of major degradation products like PFCAs, FTSAs, or PFOS and their distribution of carbon chain lengths indicate the activity of biotic or abiotic degradation processes and selective leaching processes from the upper soil horizons., (© 2021. The Author(s).)

This manuscript reports on a simple paper-based bienzymatic colorimetric assay for sarcosine as an important urinary biomarker of prostate cancer. All required assay reagents are pre-deposited on hydrophilic filter paper spots surrounded by a hydrophobic barrier. Sarcosine in the sample solution is selectively oxidized in the presence of sarcosine oxidase (SOx), resulting in the formation of hydrogen peroxide, which is subsequently detected through the horseradish peroxidase (HRP)-catalyzed conversion of the colorless indicator 3,3',5,5'-tetramethylbenzidine (TMB) into its blue-colored oxidation product. By the modification of the paper with positively charged poly(allylamine hydrochloride) (PAH), a linear response to sarcosine between 0 and 10 μM and a significant lowering of the limit of detection (LOD) (0.6 μM) compared to the unmodified paper substrate (12.6 μM) has been achieved. The improvement of the LOD was attributed to the fact that the presence of the polymer limits the enzyme-driven colorimetric reaction to the surface of the paper substrate, resulting in stronger color development. In experiments in artificial urine matrix, the bicarbonate anion was identified as an inhibitor of the colorimetric reaction. This inhibition was successfully eliminated through on-device sample pH adjustments with pH-buffer components pre-deposited onto assay devices. The LOD for sarcosine achieved in artificial urine matrix (2.5 μM) is below the 5 μM threshold value for this urinary biomarker required for diagnostic purposes. Finally, good selectivity over all 20 natural amino acids and satisfactory long-term storage stability of reagent-modified paper substrates at - 20 °C for a period of 50 days were confirmed., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

A combination of thin-film microextaction based on an aptamer immobilized on modified Whatman cellulose paper followed by electrospray ionization ion mobility spectrometry has been developed for the analysis of codeine in urine samples. The immobilization is based on the covalent linking of an amino-modified anticodeine aptamer to aldehyde groups of the oxidized cellulose paper. The covalent bonds were examined by infrared spectroscopy and elemental analysis. The effect of the extraction parameters, including the elution conditions (solvent type and volume), extraction time, and extraction temperature, on the extraction efficiency were investigated. Under the optimized conditions, the linear dynamic range was found to be 10-300 ng/mL with a detection limit of 3.4 ng/mL for codeine in urine. The relative standard deviation was 6.8% for three replicate measurements of codeine at 100 ng/mL in urine. Furthermore, the samples were analyzed with a standard method for the analysis of codeine using high-performance liquid chromatography with ultraviolet detection. The comparison of the results validates the accuracy of the proposed method as an alternative method for the analysis of codeine in urine samples.

Paper-based devices serve to address many analytical questions both inside and outside of the laboratory setting. For the first time, yeast is 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 4 °C. 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.

This White Paper by the European Society for Swallowing Disorders (ESSD) reports on the current state of screening and non-instrumental assessment for dysphagia in adults. An overview is provided on the measures that are available, and how to select screening tools and assessments. Emphasis is placed on different types of screening, patient-reported measures, assessment of anatomy and physiology of the swallowing act, and clinical swallowing evaluation. Many screening and non-instrumental assessments are available for evaluating dysphagia in adults; however, their use may not be warranted due to poor diagnostic performance or lacking robust psychometric properties. This white paper provides recommendations on how to select best evidence-based screening tools and non-instrumental assessments for use in clinical practice targeting different constructs, target populations and respondents, based on criteria for diagnostic performance, psychometric properties (reliability, validity, and responsiveness), and feasibility. In addition, gaps in research that need to be addressed in future studies are discussed. The following recommendations are made: (1) discontinue the use of non-validated dysphagia screening tools and assessments; (2) implement screening using tools that have optimal diagnostic performance in selected populations that are at risk of dysphagia, such as stroke patients, frail older persons, patients with progressive neurological diseases, persons with cerebral palsy, and patients with head and neck cancer; (3) implement measures that demonstrate robust psychometric properties; and (4) provide quality training in dysphagia screening and assessment to all clinicians involved in the care and management of persons with dysphagia., (© 2021. The Author(s).)

Paper sheets represent one of the infection risk sources inside educational and administrative institutions under biological pandemics. So, the present study aimed to validate the efficiency of gamma radiation or dry heat techniques to sterilize contaminated paper sheets with different indicator pathogens while retaining their structure. The results showed that gamma radiation at 6, 12, or 24 kGy can successfully kill Gram-positive bacteria such as Bacillus cereus and Staphylococcus aureus, Gram-negative bacteria such as Escherichia coli and Salmonella typhi, and fungi such as Candida albicans. Moreover, dry heating at 100 °C for 60 min, 150 °C for 30 min, or 200 °C for 15 min can be successful in paper decontamination of all tested species. Surprisingly, scanning electron microscopy (SEM) micrographs proved that gamma radiation at 6 kGy, dry heat at 100 °C for 60 min or 150 °C for 30 min or 200 °C for 15 min, is suitable for paper sheet sterilization while maintaining their structure. Ultimately, dry heat is a simple, effective, fast, safe, and inexpensive technique for paper sterilization. It may be used as a precautionary step inside educational institutions, especially during written examination periods, to ensure a safe life for academic members during biological pandemics such as COVID-19., (© 2022. The Author(s).)

Mercury ions (Hg 2+ ) mediating in situ heterojunction formation strategy based on spatially separated dual working areas was developed to achieve sensitive detection of human immunoglobulin G. To be specific, the complex of antibody, the silicon dioxide, and thymine-rich hairpin DNA were immobilized onto the antigen and antibody-modified electrodes, forming a special sandwich type where T-Hg 2+ -T structure could accommodate Hg 2+ . The zinc ions from zinc sulfide (ZnS) photoelectric materials were captured by Hg 2+ to convert ZnS to zinc sulfide-mercuric sulfide nanocomposite. Such ion exchange approach with spatially separated working electrodes endowed the sensing platform with lower background interference and high selectivity, which also avoided damage of illumination on biomolecules. In addition, by regulating the ion recognition probe, the protocol could be extended to numerous other fields like clinical diagnosis, environmental monitoring, and public safety., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

A new contact stamping method for fabrication of paper-based analytical devices (PADs) is reported. It uses an all-purpose acrylic varnish and 3D-printed stamps to pattern hydrophobic structures on paper substrates. The use of 3D printing allows quickly prototyping the desired stamp shape without resorting to third-party services, which are often expensive and time consuming. To the best of our knowledge, this is the first report regarding the use of this material for creation of hydrophobic barriers in paper substrates, as well as this 3D printing-based stamping method. The acrylic varnish was characterized and the features of the stamping method were studied. The PADs developed here presented better compatibility with organic solvents and surfactants compared with similar protocols. Furthermore, the use of this contact stamping method for fabrication of paper electrochemical devices was also possible, as well as multiplexed microfluidic devices for lateral flow testing. The analytical applicability of the varnish-based PADs was demonstrated through the image-based colorimetric quantification of iron in pharmaceutical samples. A limit of detection of 0.61 mg L -1 was achieved. The results were compared with spectrophotometry for validation and presented great concordance (relative error was < 5% and recoveries were between 104 and 108%). Thus, taking into account the performance of the devices explored here, we believe this novel contact stamping method is a very interesting alternative for production of PADs, exhibiting great potentiality. In addition, this work brings a new application of 3D printing in analytical sciences., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: The aims of the study were: (1) to clarify the definitions of "migrant" used in occupational health research; (2) to summarize migrant workers' industry sectors, occupations and employment conditions; (3) to identify the occupational health and safety services available to migrant workers; (4) to summarize work-related health problems found among migrant workers; (5) to identify the methodological challenges to research into occupational health of migrant workers; and (6) to recommend improvements in migrant occupational health research., Methods: This position paper was prepared by researchers from several European countries and Australia, working within the EU COST Action OMEGA-NET. The paper drew on two recent systematic reviews on the occupational health of international migrant workers and other literature, and also identified uncertainties and gaps in the research literature. Migrants may, for example, be temporary or permanent, moving for specific jobs migrants or other reasons. Their ethnicity and language capabilities will affect their work opportunities., Results: The occupational health literature seldom adequately identifies the heterogeneity or characteristics of the migrant group being studied. Migrants tend to work in more physically and mentally demanding environments with higher exposures than native workers. Migrants tend to have an increased risk of physical and mental ill health, but less access to health care services. This has been demonstrated recently by high rates of COVID-19 and less access to health care. There have been a number of cross-sectional studies of migrant health but few long-term cohort studies were identified. Other study designs, such as registry-based studies, surveys and qualitative studies may complement cross-sectional studies. Mixed-methodology studies would be valuable in research on migrants' occupational health. Language and lack of trust are barriers to migrant research participation., Conclusion: Targeted research, especially longitudinal, identifying how these economically important but often-vulnerable workers can be best assisted is needed. Researchers should identify the characteristics of the migrant workers that they are studying including visa/migration circumstances (temporary, permanent, undocumented), racial and ethnic characteristics, existing skills and language abilities., (© 2021. The Author(s).)

The use of electrospun nanofibers as functional material in paper-based lateral flow assays (LFAs) was studied. Specific chemical features of the nanofibers were achieved by doping the base polymer, poly(lactic acid) (PLA), with poly(ethylene glycol) (PEG) and polystyrene8K-block-poly(ethylene-ran-butylene)25K-block-polyisoprene10K-Brij76 (K3-Brij76) (KB). The LFAs were assembled such that the sample flowed through the nanofiber mat via capillary action. Initial investigations focused on the sustainable spinning and assembly of different polymer structures to allow the LFA format. Here, it was found that the base polymer poly(vinyl alcohol) (PVA), which was shown to function well in microfluidic biosensors, did not work in the LFA format. In contrast, PLA-based nanofibers enabled easy assembly. Three relevant features were chosen to study nanofiber-based functionalities in the LFA format: adsorption of antibodies, quantification of results, and nonspecific binding. In particular, streptavidin-conjugated sulforhodamine B (SRB)-encapsulating liposomes were captured by anti-streptavidin antibodies adsorbed on the nanofibers. Varying the functional polymer concentration within the PLA base enabled the creation of distinct capture zones. Also, a sandwich assay for the detection of Escherichia coli O157:H7 was developed using anti-E. coli antibodies as capture and reporter species with horseradish peroxidase for signal generation. A dose-response curve for E. coli with a detection limit of 1.9 × 10(4) cells was achieved. Finally, functional polymers were used to demonstrate that nonspecific binding could be eliminated using antifouling block copolymers. The enhancement of paper-based devices using functionalized nanofibers provides the opportunity to develop a broad spectrum of sensitive and specific bioassays with significant advantages over their traditional counterparts.

Respiratory viral infections often mimic the symptoms of infections caused by bacteria; however, restricted and targeted administration of antibiotics is needed to combat growing antimicrobial resistance. This is particularly relevant in low-income settings. In this work, we describe the use of isothermal amplification of viral DNA at 37 °C coupled to a paper-based vertical flow microarray (VFM) setup that utilizes a colorimetric detection of amplicons using functionalized gold nanoparticles. Two oligonucleotide probes, one in-house designed and one known adenoviral probe were tested and validated for microarray detection down to 50 nM using a synthetic target template. Furthermore, primers were shown to function in a recombinase polymerase amplification reaction using both synthetic template and viral DNA. As a proof-of-concept, we demonstrate adenoviral detection with four different adenoviral species associated with respiratory infections using the paper-based VFM format. The presented assay was validated with selected adenoviral species using the in-house probe, enabling detection at 1 ng of starting material with intra- and inter-assay %CV of ≤ 9% and ≤ 13%. Finally, we validate our overall method using clinical samples. Based on the results, the combination of recombinase polymerase amplification, paper microarray analysis, and nanoparticle-based colorimetric detection could thus be a useful strategy towards rapid and affordable multiplexed viral diagnostics.

The incidence of flavivirus infections has increased dramatically in recent decades in tropical and sub-tropical areas worldwide, affecting hundreds of millions of people each year. Dengue viruses are typically transmitted by mosquitoes and can cause a wide range of symptoms from flu-like fever to organ impairment and death. Although conventional diagnostic tests can provide early diagnosis of acute dengue infections, access to these tests is often limited in developing countries. Consequently, there is an urgent need to develop affordable, simple, rapid, and robust diagnostic tools that can be used at 'Point of Care' settings. Early diagnosis is crucial to improve patient management and reduce the risk of complications. In the present study, a novel laser-cut device made of glass-fiber paper was designed and tested for the detection of the dengue Non Structural 1 (NS1) viral protein and specific IgM in blood and plasma. The device, called PAD, was able to detect around 25 ng/mL of NS1 protein in various sample types in 8 minutes, following a few simple steps. The PAD was also able to detect specific IgM in human plasmas in less than 10 minutes. The PAD appears to have all the potential to assist health workers in early diagnosis of dengue fever or other tropical fevers caused by flaviviruses.