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There is current interest in replacing petroleum-based additives in consumer paper products with abundantly available, renewable and sustainable biopolymers such as lignin-containing cellulose nanofibers (LCNFs) and cottonseed protein. This research characterized the performance of cottonseed protein isolate with/without LCNFs to increase the dry strength of filter paper. The application of 10% protein solution with 2% LCNFs as an additive improved the elongation at break, tensile strength and modulus of treated paper products compared to the improved performance of cottonseed protein alone. Improvements in tensile modulus and tensile strength were greatest for samples containing larger amounts of lignin and a greater degree of polymerization than for those with less lignin from the same biomass sources. [ABSTRACT FROM AUTHOR]

Background: Autohydrolysis is an extensively investigated pretreatment method due to its environmental friendliness. During autohydrolysis, most xylan from hemicellulose can be converted into xylooligosaccharides (XOS), and cellulose in the autohydrolyzed residues can be transformed into glucose after enzymatic hydrolysis. Both of these are value-added biochemicals in the biorefining process. In this work, paper mulberry (PM), which contains abundant protein, was utilized as a raw material to coproduce XOS and single-cell protein (SCP) through autohydrolysis and fermentation technologies. Results: The results showed that 8.3 g of XOS and 1.8 g of amino acids could be recovered in the autohydrolysate (based on 100 g raw material) after autohydrolysis (170 °C, 1 h). Moreover, 5.7 g of low-DP XOS along with 1.8 g of amino acids could be further obtained from the autohydrolysate after hydrolysis with endo-β-1-4-xylanase. In addition, 20.1 g of fermentable monosaccharides was recovered after hydrolyzing the autohydrolyzed PM with cellulase, which can be used to produce 4.8 g of SCP after fermentation with Candida utilis. Conclusion: As a valuable application of PM, a novel process is proposed to coproduce amino acid-rich XOS and SCP through autohydrolysis. The carbohydrate of PM is effectively converted to high value-added products. [ABSTRACT FROM AUTHOR]

Exposure to natural rubber latex (NRL) can result in sensitivity to NRL protein with resulting allergic reactions. Low-cost, portable, simple, sensitive analytical tools for NRL protein measurements are needed for rapid and accurate assessments of allergenic risks at the point-of-care (POC) instead of using traditional methods that require large and expensive instruments, long-time analysis, and complex sample preparation steps. Here, an electrochemical paper-based analytical device (ePAD) is presented by combining sample preparation and electrochemical detection within a single device to offer a one-step NRL analysis. The lack of antibodies and/or enzymes against NRL makes POC analysis difficult. In this work, detection is based on electrochemical measurement of the remaining Cu after in situ protein complexation instead of more complex biological assays for the first time. Graphene screen-printed electrodes modified with 1,10-phenanthroline and Nafion were used in the ePAD to improve Cu signal 18-fold relative to unmodified carbon screen-printed electrodes. The optimum parameters including 1,10-phenanthroline concentration, reaction time between Cu and protein, and the starting Cu concentration were 5% w/v, 1 min, and 600 μg mL−1, respectively. In addition to short analysis time (4 min), the system selectivity indicated no other interfering species affecting protein detection. The proposed ePAD achieved an LOD of 3.0 mg dL−1 and a linear range of 10.0–200.0 mg dL−1. Finally, the proposed sensors were applied for NRL protein detection and the results were not significantly different from the traditional Lowry method at 95% confidence. [ABSTRACT FROM AUTHOR]

Paper-based analytical device (PAD) has received more and more attention in the field of point-of-care test (POCT) due to its low cost, portability and simple operation. Sensitivity and selectivity are two important aspects in clinical diagnostic analysis. However, low sensitivity of a PAD limits its wider application for POCT. Here we introduced a PAD that can clean and enrich the protein content from salty media with both electric field (E) and pH gradient (double E/pH gradients), with which 100-fold enrichment effect could be achieved within 70 s as demonstrated by fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) from artificial urine media. With post staining of the protein stacking band with bromophenol blue (BPB), selective colorimetric detection of human serum albumin (HSA) was achieved simply with smartphone camera in the clinically significant range of 10–300 mg‧L−1 (R2 = 0.99) with a limit of detection (LOD) of 4.9 mg‧L−1. Detection of microalbuminuria (MAU) of diabetic patients was demonstrated with this method without difference (ɑ = 0.01) to that by the clinical method (immunoturbidimetry). This work demonstrated the potential of this PAD method in online sample pretreatment and detection of target component from complex physiological samples. Image 1 • Both electric field and pH gradient (E/pH double gradients) can be established and sustained on a paper fluidic channel. • Ampholytic content from salty sample media can be stacked/separated from other types of species. • Proteins from urine can be cumulatively stacked on the double gradient interface without intensive pre-treatment. • Sensitive and selective colorimetric detection of microalbuminuria (MAU) from clinical samples was successfully demonstrated. [ABSTRACT FROM AUTHOR]

This work presents an annotation tool that automatically locates mentions of particular amino‐acid residues in published papers and identifies the protein concerned. These matches can be provided in context or in a searchable format in order for researchers to better use the existing and future literature. [ABSTRACT FROM AUTHOR]

This work reports on fully integrated "sample‐in‐signal‐out" microfluidic paper‐based analytical devices (μPADs) relying on bioluminescence resonance energy transfer (BRET) switches for analyte recognition and colorimetric signal generation. The devices use BRET‐based antibody sensing proteins integrated into vertically assembled layers of functionalized paper, and their design enables sample volume‐independent and fully reagent‐free operation, including on‐device blood plasma separation. User operation is limited to the application of a single drop (20–30 μL) of sample (serum, whole blood) and the acquisition of a photograph 20 min after sample introduction, with no requirement for precise pipetting, liquid handling, or analytical equipment except for a camera. Simultaneous detection of three different antibodies (anti‐HIV1, anti‐HA, and anti‐DEN1) in whole blood was achieved. Given its simplicity, this type of device is ideally suited for user‐friendly point‐of‐care testing in low‐resource environments. A single drop of blood on paper: Bioluminescent sensing proteins integrated into a multi‐layer paper‐based device allow the user‐friendly and simple quantification of monoclonal antibodies from a single drop of blood by simple color change monitoring. [ABSTRACT FROM AUTHOR]

Proteinaceous toxins are harmful proteins derived from plants, bacteria, and other natural sources. They pose a risk to human health due to infection and also as possible biological warfare agents. Paper spray mass spectrometry (PS-MS) with wipe sampling was used to detect proteins from surfaces as a potential tool for identifying the presence of these toxins. Proteins ranging in mass between 12.4 and 66.5 kDa were tested, including a biological toxin simulant/vaccine for Staphylococcal enterotoxin B (SEBv). Various substrates were tested for these representative proteins, including a laboratory bench, a notebook cover, steel, glass, plant leaf and vinyl flooring. Carbon sputtered porous polyethylene (CSPP) was found to outperform typical chromatography paper used for paper spray, as well as carbon nanotube (CNT)-coated paper and polyethylene (PE), which have been previously shown to be well-suited for protein analysis. Low microgram quantities of the protein toxin simulant and other test proteins were successfully detected with good signal-to-noise from surfaces using a porous wipe. These applications demonstrate that PS-MS can potentially be used for rapid, sample preparation-free detection of proteins and biological warfare agents, which would be beneficial to first responders and warfighters. [ABSTRACT FROM AUTHOR]

Abstract A novel affinity paper-based electrochemical impedance device (PEID) was first fully developed for cardiovascular risk assessment. Herein, a simple folding PEID comprising a dual screen-printed electrode was fabricated for label-free electrochemical impedance detection. The results demonstrated in a step-wise manner that the phosphocholine-modified screen-printed carbon electrodes were highly responsive to the clinically required range of C-reactive protein (CRP) (0.005 – 500 mg L−1; r2 = 0.993) levels with a detection limit (3σ/slope) of 0.001 mg L−1. The optimal binding frequency of CRP–phosphocholine interaction was determined to be 100 Hz. These results implied that our proposed system could be used for simultaneously measuring the CRP levels using a single PEID platform in combination with the specific recognition elements. When assaying two levels of CRP, the overall assay reproducibility for each concentration, expressed as relative standard error of the mean (RSE%; n = 30), was 1.21%. The variation in the measurements between individual electrodes, expressed as the relative standard deviation (RSD), was 2.82%. Using 2 measurement sites per device, the proposed sensor provided excellent precision for the simultaneous detection of CRP. Moreover, the RSD for the CRP levels measured on ten independently fabricated paper-based sheets was 2.11%, thereby offering an acceptable fabrication reproducibility. The presented folding PEIDs were used forthe determination of CRP in patient-derived blood samples with minimised bias and excellent correlation with a standard method (n = 15; CUSUM linearity test, p > 0.10), thus permitting the potential application of PEID for assessing cardiovascular risk in individuals. Highlights • A PEID was developed for ultrasensitive label-free EIS detection of hs-CRP. • A simply folding step intended to create a small chamber for electrochemical assay. • A single specific-frequency determination facilitates fast impedance measurements. • An excellent agreement was demonstrated between the PEID and the standard method. [ABSTRACT FROM AUTHOR]

The article focuses on the prognostic significance of galectin-3 in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Topics include the association between high galectin-3 levels and heart failure development, rehospitalization, and adverse cardiovascular events in STEMI patients post-PCI, though it's not an independent predictor of cardiovascular mortality.

Biosensors have emerged as a valuable tool with high specificity and sensitivity for fast and reliable detection of hazardous substances in drinking water. Numerous substances have been addressed using synthetic biology approaches. However, many proposed biosensors are based on living, genetically modified organisms and are therefore limited in shelf life, usability and biosafety. We addressed these issues by the construction of an extensible, cell-free biosensor. Storage is possible through freeze drying on paper. Following the addition of an aqueous sample, a highly efficient cell-free protein synthesis (CFPS) reaction is initiated. Specific allosteric transcription factors modulate the expression of ‘superfolder’ green fluorescent protein (sfGFP) depending on the presence of the substance of interest. The resulting fluorescence intensities are analyzed with a conventional smartphone accompanied by simple and cheap light filters. An ordinary differential equitation (ODE) model of the biosensors was developed, which enabled prediction and optimization of performance. With an optimized cell-free biosensor based on the Shigella flexneri MerR transcriptional activator, detection of 6 μg/L Hg(II) ions in water was achieved. Furthermore, a completely new biosensor for the detection of gamma-hydroxybutyrate (GHB), a substance used as date-rape drug, was established by employing the naturally occurring transcriptional repressor BlcR from Agrobacterium tumefaciens. [ABSTRACT FROM AUTHOR]

There have been limited studies on the potential use of enzymes for enhancing the dewaterability of biosludge. The mechanisms for such enhancement have not been investigated despite the environmental advantages of using enzymes over synthetic polymers for biosludge conditioning. In order to find enzymes with this potential, a screening of commercially available enzymes was carried out using capillary suction time to assess biosludge dewaterability. The only enzyme that showed dewatering improvements in the screening tests was a lysozyme which reduced the capillary suction time by 36% and increased the cake solids content from 5.6 to 8.9 DS%. Lysozyme aided in the flocculation of particles reducing the polymer demand from 11% to 6%. Active and inactive lysozyme exhibited a similar ability for enhancing sludge dewatering, indicating that the conditioning mechanism of lysozyme is similar to that of a flocculant. [ABSTRACT FROM AUTHOR]

Background: It is important for industries to find green chemistries for manufacturing their products that have utility, are cost-effective and that protect the environment. The paper industry is no exception. Renewable resources derived from plant components could be an excellent substitute for the chemicals that are currently used as paper binders. Air laid pressed paper products that are typically used in wet wipes must be bound together so they can resist mechanical tearing during storage and use. The binders must be strong but cost-effective. Although chemical binders are approved by the Environmental Protection Agency, the public is demanding products with lower carbon footprints and that are derived from renewable sources. Results: In this project, carbohydrates, proteins and phenolic compounds were applied to air laid, pressed paper products in order to identify potential renewable green binders that are as strong as the current commercial binders, while being organic and renewable. Each potential green binder was applied to several filter paper strips and tested for strength in the direction perpendicular to the cellulose fibril orientation. Out of the twenty binders surveyed, soy protein, gelatin, zein protein, pectin and Salix lignin provided comparable strength results to a currently employed chemical binder. Conclusions: These organic and renewable binders can be purchased in large quantities at low cost, require minimal reaction time and do not form viscous solutions that would clog sprayers, characteristics that make them attractive to the non-woven paper industry. As with any new process, a large-scale trial must be conducted along with an economic analysis of the procedure. However, because multiple examples of "green" binders were found that showed strong cross-linking activity, a candidate for commercial application will likely be found. [ABSTRACT FROM AUTHOR]

Abstract In this study, levels of inflammatory protein biomarkers in venous plasma, plasma derived from capillary blood from the earlobe, and capillary plasma stored as dried plasma spots (DPS) were compared. Samples from 12 male individuals were assessed with a panel of 92 inflammation-related proteins using multiplex proximity extension assay. Correlations between sample types varied greatly between analytes. A high correlation of ρ > 0.8 was observed between capillary plasma and DPS for 32 analytes. At this level of correlation, 13 analytes correlated between venous and capillary plasma and 5 analytes in the comparison of venous blood with DPS. Highlights • Measurement of an inflammation protein panel in three sample sources. • Earlobe plasma as a less invasive alternative sample source than venous plasma. • Protein measurement in capillary plasma stored as dried plasma spots (DPS). • Correlation value of ρ > 0.8 between capillary earlobe plasma and DPS for 32 analytes. • Correlation value of ρ > 0.8 between venous and capillary earlobe plasma for 13 analytes. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) is increasing in incidence and predictable with measurement of serum islet autoantibodies (iAb) years prior to clinical disease onset. Identifying iAb positive individuals reduces diabetic ketoacidosis and identifies individuals for T1D prevention trials. However, large scale screening for iAb remains challenging as assays have varying sensitivities and specificities, insulin autoantibodies remain difficult to measure and venipuncture is generally required to obtain serum. We developed an approach to reliably measure all four major iAb, including insulin autoantibodies, from dried blood spots (DBS) on filter-paper. By spiking iAb positive serum into iAb negative whole blood in a dose titration, we optimized the conditions for autoantibody elution from filter paper as measured by fluid phase radioimmunoassays. After assessing stability of measuring iAb from DBS over time, we then screened iAb from DBS and the corresponding serum in new-onset T1D (n = 52), and controls (n = 72) which included first-degree relatives of T1D patients. iAb measured from eluted DBS in new-onset T1D strongly correlated with serum measurements (R2 = 0.96 for mIAA, GADA = 0.94, IA-2A = 0.85, ZnT8A = 0.82, p<0.01 for each autoantibody). There were no false positives in control subjects, and 5/6 with previously unknown iAb positivity in sera were detected using DBS. With further validation, measuring iAb from DBS can be a reliable method to screen for T1D risk. [ABSTRACT FROM AUTHOR]

Sensitivity is an important factor determining successful mass spectrometry (MS) analysis of metabolome, protein, drugs, and environmental samples. Currently, nanoelectrospray ionization (ESI) is widely used as a sensitive ionization method. However, application of nano-ESI is limited to polar molecules and there is no atmospheric pressure ionization technique developed that can be used for MS analysis of low- and nonpolar compounds with sensitivity that can match with nano-ESI. Herein, we propose paper spray chemical ionization (PSCI) as an ionization technique that can be used to analyze low- and nonpolar aromatic compounds with high sensitivity. PSCI is based on paper spray ionization utilizing corona discharge phenomenon. PSCI can sensitively and quantitatively detect down to picogram (or femtomole) levels of low- and nonpolar aromatic compounds. [ABSTRACT FROM AUTHOR]

Deploying anti-CRISPR proteins is a potent strategy used by phages to inhibit bacterial CRISPR-Cas defense. In a new Nature paper, Trost et al. 1 discover and characterize an exciting anti-CRISPR mechanism with possible implications beyond this microscopic arms race. Deploying anti-CRISPR proteins is a potent strategy used by phages to inhibit bacterial CRISPR-Cas defense. In a new Nature paper, Trost et al. discover and characterize an exciting anti-CRISPR mechanism with possible implications beyond this microscopic arms race. [ABSTRACT FROM AUTHOR]

Abstract: Dried blood spot samples (DBSS) on filter paper offer several advantages compared to conventional serum/plasma samples: they do not require any phlebotomy or separation of blood by centrifugation; they are less invasive; they allow sample stability and shipment at room temperature; and they pose a negligible risk of infection with blood-borne viruses, such as HIV, HBV and HCV, to those who handle them. Therefore dried blood spot samples (DBSS) on filter paper can be a quick, convenient and inexpensive means of obtaining blood samples for biomarker discovery, disease screening, diagnosis and treatment monitoring in non-hospitalized, public health settings. In this study, we investigated for the first time the potential application of dried blood spot samples (DBSS) in protein expression profiling using antibody array technology. First, optimal conditions for array assay performance using dried blood spot samples (DBSS) was established, including sample elution buffer, elution time, elution temperature and assay blocking buffer. Second, we analyzed dried blood spot samples (DBSS) using three distinct antibody array platforms, including sandwich-based antibody arrays, quantitative antibody arrays and biotin-label-based antibody arrays. In comparison with paired serum samples, detection of circulating proteins in dried blood spot samples (DBSS) correlated well for both low- and high-abundance proteins on all three antibody array platforms. In conclusion, our study strongly indicates the novel application of multiplex antibody array platforms to analyze dried blood spot samples (DBSS) on filter paper represents a viable, cost-effective method for protein profiling, biomarker discovery and disease screening in a large, population-based survey. [Copyright &y& Elsevier]

Many results have been obtained when studying scientific papers citations databases in a network perspective. Articles can be ranked according to their current in-degree and their future popularity or citation counts can even be predicted. The dynamical properties of such networks and the observation of the time evolution of their nodes started more recently. This work adopts an evolutionary perspective and proposes an original algorithm for the construction of genealogical trees of scientific papers on the basis of their citation count evolution in time. The fitness of a paper now amounts to its in-degree growing trend and a “dying” paper will suddenly see this trend declining in time. It will give birth and be taken over by some of its most prevalent citing “offspring”. Practically, this might be used to trace the successive published milestones of a research field. [ABSTRACT FROM AUTHOR]

Required metrological tools, such as higher order reference measurements procedures, pure substance and matrix certified reference materials, are established for small well defined molecules. Difficulties still remain in the provision of SI traceable standards in the area of larger biomolecules such as peptides/proteins. The provision of Primary Calibration Reference Services has been identified as a core technical competency for National Measurement Institutes (NMIs). A concept has been elaborated by the Focus Group I on peptide/protein purity for the strategic planning of ongoing Key Comparisons of the Protein Analysis Working Group (PAWG) within the Comité Consultatif pour la Quantité de Matière (CCQM). The assignment of the mass fraction content of high purity peptide/protein materials will be the subject of the CCQM-K115/P55.2 comparison series to directly support NMI services and certified reference materials currently being provided by NMIs. [ABSTRACT FROM AUTHOR]

Blood cells are the most integral part of the body, which are made up of erythrocytes, platelets and white blood cells. The examination of subcellular structures and proteins within blood cells at the nanoscale can provide valuable insights into the health status of an individual, accurate diagnosis, and efficient treatment strategies for diseases. Super-resolution microscopy (SRM) has recently emerged as a cutting-edge tool for the study of blood cells, providing numerous advantages over traditional methods for examining subcellular structures and proteins. In this paper, we focus on outlining the fundamental principles of various SRM techniques and their applications in both normal and diseased states of blood cells. Furthermore, future prospects of SRM techniques in the analysis of blood cells are also discussed. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a fatal disease. As its pathological mechanisms are not well understood, there are no efficient therapeutics for it at present. While it is highly heterogenous both etiologically and clinically, it has a common salient hallmark, i.e., aberrant protein aggregation (APA). The upstream pathogenesis and the downstream effects of APA in ALS are sophisticated and the investigation of this pathology would be of consequence for understanding ALS. In this paper, the pathomechanism of APA in ALS and the candidate treatment strategies for it are discussed. [ABSTRACT FROM AUTHOR]

AbstractOvotransferrin(OVT)is a protein found in many types of egg white and has a wide range of functional properties. It has 50% homology with human/bovine lactoferrin, and is expected to be one of the most important alternative proteins for use in food and nutritional applications. This paper mainly reviews the structural characteristics and chemical properties of OVT, as well as its extraction and purification methods. It also systematically describes the various biological activities of OVT and its applications in food and medical industries. The challenges and limitations in the research of OVT were suggested. This review recommends some possible methods such as nanoparticle carriers and microencapsulation to improve the bioavailability and stability of OVT. In addition, this review highlights several strategies to overcome the limitations of OVT in terms of preparation and purification. This review systematically summarizes the recent advances in OVT and will provide guidance for the its development for food and nutritional applications. [ABSTRACT FROM AUTHOR]

Adding carbonyl groups into the hydrogel matrix improves the stability and biocompatibility of the hydrogels, making them suitable for different biomedical applications. In this review article, we will discuss the use of hydrogels based on polysaccharides modified by oxidation, with particular attention paid to the introduction of carbonyl groups. These hydrogels have been developed for several applications in tissue engineering, drug delivery, and wound healing. The review article discusses the mechanism by which oxidized polysaccharides can introduce carbonyl groups, leading to the development of hydrogels through cross-linking with proteins. These hydrogels have tunable mechanical properties and improved biocompatibility. Hydrogels have dynamic properties that make them promising biomaterials for various biomedical applications. This paper comprehensively analyzes hydrogels based on cross-linked proteins with carbonyl groups derived from oxidized polysaccharides, including microparticles, nanoparticles, and films. The applications of these hydrogels in tissue engineering, drug delivery, and wound healing are also discussed. [ABSTRACT FROM AUTHOR]

Sequence database searches followed by homology-based function transfer form one of the oldest and most popular approaches for predicting protein functions, such as Gene Ontology (GO) terms. These searches are also a critical component in most state-of-the-art machine learning and deep learning-based protein function predictors. Although sequence search tools are the basis of homology-based protein function prediction, previous studies have scarcely explored how to select the optimal sequence search tools and configure their parameters to achieve the best function prediction. In this paper, we evaluate the effect of using different options from among popular search tools, as well as the impacts of search parameters, on protein function prediction. When predicting GO terms on a large benchmark dataset, we found that BLASTp and MMseqs2 consistently exceed the performance of other tools, including DIAMOND—one of the most popular tools for function prediction—under default search parameters. However, with the correct parameter settings, DIAMOND can perform comparably to BLASTp and MMseqs2 in function prediction. Additionally, we developed a new scoring function to derive GO prediction from homologous hits that consistently outperform previously proposed scoring functions. These findings enable the improvement of almost all protein function prediction algorithms with a few easily implementable changes in their sequence homolog-based component. This study emphasizes the critical role of search parameter settings in homology-based function transfer and should have an important contribution to the development of future protein function prediction algorithms. [ABSTRACT FROM AUTHOR]

Objective: Sertoli–Leydig cell tumors (SLCTs) are rare neoplasms occurring in young women with 60% associated with DICER1 mutations. This is only the second published case series of patients with SLCTs with associated DICER1 gene alterations. DICER1 syndrome is a rare inherited tumor‐susceptibility syndrome affecting organs such as the ovaries. We use this case series to inform readers on this increasingly important condition in gynecology. Methods and Results: We present three young females presenting with secondary amenorrhoea, hirsutism, acne and in one case tonic–clonic seizures. All cases had high testosterone levels and an adnexal mass on ultrasound. Following surgical removal, pathology confirmed SLCTs and genetic testing followed. All three patients had DICER1 syndrome with two patients subsequently found to be related. Discussion: The prevalence of DICER1 syndrome in the population is estimated to be 1 in 10 000 with a spectrum of sex cord stromal tumors affecting young women. The associated pathological classifications and management. This paper describes the DICER1 gene and the associated tumor predisposition syndrome alongside a surveillance protocol for use in clinical practice. It promotes discussion over the importance of early clinical genetics involvement in sex‐cord stromal tumors and the associated difficulties in counseling in a young patient population. Genetic testing and early detection are imperative for targeted surveillance of at‐risk organs to be performed but despite this there is no international guidance. The cases highlight the psychological impact of tumors in young patients and provokes an ethical discussion over DICER1 gene's inclusion in preimplantation genetics. Conclusions: DICER1 syndrome is a rare but increasingly important condition in pediatric and adolescent gynecology with a paucity of published data and case reports. This makes international consensus on management and surveillance difficult. [ABSTRACT FROM AUTHOR]

We studied the aging behaviour of gelatin used to size paper. Thus far, research on the aging of paper has largely ignored the sizing agent. Degradation of the protein was characterised and the impact of paper components, such as cellulose, and aluminium potassium sulphate was evaluated. Whatman No. 1 filter papers sized with two types of gelatins (A and B) were prepared as model samples. Commercially sized modern papers (Arches) were also studied in order to compare laboratory samples with real artist papers. Both types of papers were artificially aged (80 °C, 50% relative humidity for 35 and 94 days). Historic papers were included in the study in order to compare artificially aged with naturally aged gelatin. The aqueous extracts from the papers were characterised by aqueous size-exclusion chromatography (SEC) using four PL-Aquagel-OH columns and UV photodiode array detection at 220, 254 and 280 nm. Results showed that gelatin undergoes hydrolysis upon aging, type A gelatin showing a faster degradation rate than type B. The result was an increase in the lower-molar-mass fractions, under 50 000 g mol−1, and especially in a characteristic fraction with a peak molecular mass (Mp) of 14 000 g mol−1. A significant decrease in the extraction yields of α-, β- and γ-chains occurred after aging. This was attributed to crosslinking, leading to the formation of less-soluble polypeptides with very high molar mass (>800 000 g mol−1). Less than 10% alum had no impact on the degradation rate; higher alum contents accelerated hydrolysis reactions. [Copyright &y& Elsevier]

Integration and storage of bioactive reagents is an important and challenging task in microfluidic paper-based analytical devices (μPADs). Here, we developed a convenient and universal method to store proteins and preserve their activities in μPADs by using aqueous two-phase systems (ATPs) evolved film. A polyethylene glycol (PEG)–dextran (DEX) double-layer film was formed through dehydration of ATPs. Functional biomolecules were stored in the bottom DEX layer on the basis of the biased partitioning and rehydrated conveniently by simple addition of buffer solution at usage. As a demonstration, enzyme immunoassay (EIA) of carcinoembryonic antigen was performed successfully on μPAD integrated with antibodies. Even after 104 days of storage at 4 °C and ambient conditions, the EIA signal just lost less than 10% and 30%, which meet the storage requirements of invitro diagnosis reagents. The ATPs evolved double-layer film has double functions of stabilization and insulation, and provide a high efficiency of biomolecule preservation, thereby promoting the applications of μPADs in POC diagnostic assay. We present a universal and high efficient biomolecules preservation technique using the PEG-DEX ATPs evolved double-layer film for paper based microdevice. [Display omitted] • Antibodies and enzyme were integrated on the paper based microdevice using the ATPs evolved double-layer film. • Signals of μPADs with integrated immuno-reagents were maintained more than 90% after 104 days of storage at 4 °C conditions. • This protein storing method possessed simple operation, high compatibility, and high efficiency in preserving biomolecules. [ABSTRACT FROM AUTHOR]

Due to the unstable chemical properties and poor water solubility of carotenoids, their processing adaptation and oral bioavailability are poor, limiting their application in hydrophilic food systems. Lipid-biomacromolecular compounds can be excellent carriers for carotenoid delivery by taking full advantage of the solubilization of lipids to non-polar nutrients and the water dispersion and gastrointestinal controlled release properties of biomacromolecules. This paper reviewed the research progress of lipid-biomacromolecular compounds as encapsulation and delivery carriers of carotenoids and summarized the material selection and preparation methods for biomacromolecular compounds. By considering the interaction between the two, this paper briefly discussed the effect of these compounds on carotenoid water solubility, stability, and bioavailability, emphasizing their delivery effect on carotenoids. Finally, various challenges and future trends of lipid-biomacromolecular compounds as carotenoid delivery carriers were discussed, providing new insight into efficient loading and delivery of carotenoids. [ABSTRACT FROM AUTHOR]

Previously, single classification models were mainly studied to classify human protein cell images, i.e., to identify a certain protein based on a set of different cells. However, a classifier can identify only one protein, in fact, a single cell usually consists of multiple proteins, and the proteins are not completely independent of each other. In this paper, we build a human protein cell classification model by multi-label learning. The logical relationship and distribution characteristics among the labels are analyzed to determine the different proteins contained in a set of different cells (i.e., containing multiple elements in the output space). In this paper, using human protein image data, we conducted comparison experiments on pre-trained Xception and InceptionResnet V2 to optimize the two models in terms of data augmentation, channel settings, and model structure. The results show that the Optimized InceptionResnet V2 model achieves high performance in the classification task. The final accuracy of the Optimized InceptionResnet V2 model we obtained reached 96.1%, which is a 2.82% improvement relative to that before the optimized model. [ABSTRACT FROM AUTHOR]

Paper has been proposed as an inexpensive and versatile carrier for microfluidics devices with abilities well beyond simple capillary action for pregnancy tests and the like. Unlike standard microfluidics devices, extracting a fluid from the paper is a challenge and a drawback to its broader use. Here, we extract fluid from narrow paper strips using surface acoustic wave (SAW) irradiation that subsequently atomizes the extracted fluid into a monodisperse aerosol for use in mass spectroscopy, medical diagnostics, and drug delivery applications. Two protein molecules, ovalbumin and bovine serum albumin (BSA), have been preserved in paper and then extracted using atomized mist through SAW excitation; protein electrophoresis shows there is less than 1% degradation of either protein molecule in this process. Finally, a solution of live yeast cells was infused into paper, which was subsequently dried for preservation then remoistened to extract the cells viaSAW atomization, yielding live cells at the completion of the process. The successful preservation and extraction of fluids, proteins and yeast cells significantly expands the usefulness of paper in microfluidics. [ABSTRACT FROM AUTHOR]

We present an origami paper-based electrophoretic device (oPAD-Ep) that achieves rapid (∼5 min) separation of fluorescent molecules and proteins. Due to the innovative design, the required driving voltage is just ∼10 V, which is more than 10 times lower than that used for conventional electrophoresis. The oPAD-Ep uses multiple, thin (180 μ/layer) folded paper layers as the supporting medium for electrophoresis. This approach significantly shortens the distance between the anode and cathode, and this, in turn, accounts for the high electric field (>1 kV/m) that can be achieved even with a low applied voltage. The multilayer design of the oPAD-Ep enables convenient sample introduction by use of a slip layer as well as easy product analysis and reclamation after electrophoresis by unfolding the origami paper and cutting out desired layers. We demonstrate the use of oPAD-Ep for simple separation of proteins in bovine serum, which illustrates its potential applications for point-of-care diagnostic testing. [ABSTRACT FROM AUTHOR]

A simple method is described for the patterned deposition of Teflon on paper to create an integrated platform for parallel organic synthesis and cell-based assays. Solvent-repelling barriers made of Teflon-impregnated paper confine organic solvents to specific zones of the patterned array and allow for 96 parallel flow-through syntheses on paper. The confinement and flow-through mixing significantly improves the peptide yield and simplifies the automation of this synthesis. The synthesis of 100 peptides ranging from 7 to 14 amino acids in length gave over 60 % purity for the majority of the peptides (>95 % yield per coupling/deprotection cycle). The resulting peptide arrays were used in cell-based screening to identify 14 potent bioactive peptides that support the adhesion or proliferation of breast cancer cells in a 3D environment. In the future, this technology could be used for the screening of more complex phenotypic responses, such as cell migration or differentiation. [ABSTRACT FROM AUTHOR]

Active cellulose-based packaging materials were prepared by binding lactoferrin to paper modified with anionic polyelectrolytes. About 63% of the protein added in the slurry was present in the finished paper, corresponding to about 0.28 mg protein per cm2 of the glassine paper produced. The efficacy of the activated materials was assessed by microbiological trials, employing targets bacteria considered as spoilage and/or pathogens in food products. Lactoferrin-activated paper evidenced its efficacy against growing cells of E. coli and L. innocua, with a maximum of 0.3 and 1.3 log cycles reduction of the final population, respectively. These results can be considered a promising starting point and will be the focus of further research, aimed at developing innovative cellulose-based active food packaging. [ABSTRACT FROM AUTHOR]

Given their simplicity and functionality, paper-based microfluidic systems are considered to be ideal and promising bioassay platforms for use in less developed countries or in point-of-care services. Although a series of innovative techniques have recently been demonstrated for the fabrication of such platforms, development of simple, inexpensive and versatile new strategies are still needed in order to reach their full potential. In this communication, we describe a simple yet facile approach to fabricate paper-based sensor platforms with a desired design through a vapor-phase polymer deposition technique. We also show that the fabricated platforms could be readily employed for the detection of various biological target molecules including glucose, protein, ALP, ALT, and uric acid. The limit of detection for each target molecule was calculated to be 25 mg dL−1 for glucose, 1.04 g L−1 for protein, 7.81 unit per L for ALP, 1.6 nmol L−1 for ALT, and 0.13 mmol L−1 for uric acid. [ABSTRACT FROM AUTHOR]

Abstract: This paper described a convenient semiquantitative method for colorimetric detection of protein with self-calibration integrated on the test strip. Hydrophilic paper was employed as microfluidic device for running colorimetric assay, tree-shaped design was developed to ensure uniform microfluidic flow for multiple branches. The approach was validated with bovine serum albumin (BSA) colorimetric detection, and colorimetric results observed by naked eyes were consistent with that from apparatus. The device could be coupled with digital transmission of images for remote monitoring system for diagnosis, food control, and environmental analysis. [Copyright &y& Elsevier]

Here, we report a strategy for the design of an inexpensive paper analytical device (PAD) for quantitative detection of oligonucleotides and proteins. Detection is based on the principle of target-induced conformational switching of an aptamer linked to an electrochemical label. This simple and robust method is well matched to the equally simple and robust characteristics of the PAD platform. The demonstrated limits of detection for DNA and thrombin are 30 nM and 16 nM, respectively, and the device-to-device reproducibility is better than ±10%. The PAD has a shelf life of at least 4 weeks, involves little user intervention, and requires a sample volume of just 20 μl. [ABSTRACT FROM AUTHOR]

Paper spray (PS) ionization, an ambient ionization method, has previously been explored as a direct and fast method for mass spectrometric analysis of complex mixtures. It has been applied to the analysis of a wide variety of compounds, mostly small molecules. The work reported here extends the application of PS ionization to noncovalent protein complexes on an ion mobility tandem mass spectrometer. Similar mass spectra for protein complexes were obtained by PS ionization and nanoflow electrospray ionization (nESI), indicating that intact protein complexes can be preserved in PS ionization. In addition, collisional cross sections measured by ion mobility provide evidence that the protein assemblies may remain compact by PS ionization. With PS, it is possible to detect hemoglobin tetramer from a blood sample with minimal sample preparation. This is the first report to show that PS ionization is a promising ionization method for nonconvalent protein complexes. [ABSTRACT FROM AUTHOR]

• A paper-based multi-biocatalyst platform was successfully constructed. • Nanoporous gold with unique properties was used as supporting material. • Three different markers can be integrally detected by the multi-biocatalyst platform. • The reliable detection of L. monocytogenes was successfully realized. As biomarkers for pathogenic Listeria monocytogenes , the detection of gene hly , acetoin, and listeriolysin O (LLO) is of great significance for preventing L. monocytogenes infection and diagnosing Listeriosis. Here, a portable paper-based multi-biocatalyst platform was constructed to identify L. monocytogenes by detecting multiple biomarkers at different levels: gene hly (nucleic acid), acetoin (small molecule metabolite), and LLO (protein). The integrating detections of the three biomarkers were successfully performed by two different modified working electrodes on a single paper-based multi-biocatalyst platform. The sensitive and reliable identification of L. monocytogenes was achieved using the portable paper-based multi-biocatalyst platform with wider detection range (from 1.0 × 104 to 1.0 × 109 CFU mL−1) and lower detection limit (104 CFU mL−1). Additionally, the simpler detection procedure and shorter detection time (2 h) endows the portable platform a better detection performance compared with National Food Safety Standard Method (China-GB 4789.30-2016). Moreover, the results detected by the portable platform in spiked samples were consistent with that obtained by the real-time quantitative polymerase chain reaction method, indicating a good application potential. These unique characteristics suggest that the portable platform provides a reliable identification method for L. monocytogenes. [ABSTRACT FROM AUTHOR]

Edible insects are accepted as food and feed ingredients in many parts of the world. Insects account for more than 80% of animal kingdom providing rich biodiversity of protein and lipid profiles compared to conventional livestock. Insect biomasses contain an average of 35-62% protein, 3-57% lipid, and 3-12% chitin, and their nutritional values are widely recognized due to their presence, including minerals, and vitamins. While whole insects are consumed as eggs, larvae, pupae, or adults, there has been a recent uptick in interest to use fractions, e.g., protein, lipid, and chitin, as food and feed ingredients. To utilize these fractions in various food and feed preparations, a deeper understanding of the physicochemical as well as functional properties of the ingredients is required, which are generally impacted by extraction and preparation processes. Thus, the methods of extraction/purification are important to preserve the quality and functional properties of these ingredients. This paper discusses the extraction methods for insect protein, lipid, and chitin, their functional properties, and potential applications in food and feed applications. [ABSTRACT FROM AUTHOR]

This paper proposes to teach students biology through dance. Knowledge of nucleotides, amino acids, and structures of DNA and protein is used to create dance music and choreography. The three nucleotides (A, T, G, or C) making up the amino acids of selected proteins are converted into a musical note. In accordance with DNA's double helix structure and base-pairing, the authors designed a low-cost, in-house Dance Dance Revolution (DDR) machine to allow for a dual player dance mode that requires students to synchronize their choreography during gameplay. [ABSTRACT FROM AUTHOR]

Simple Summary: The role of neurogenic locus notch homolog protein 1 (NOTCH1)- and nuclear factor erythroid 2-related factor 2 (NRF2)-related pathways is highly heterogeneous in small cell lung cancer (SCLC) and, when they are both abnormally activated, they can synergistically cause neoplastic proliferation. In this paper, we investigate the possible role of KEAP1 silencing in NRF2 and NOTCH axis deregulation in SCLC by evaluating its impact on the modulation of cellular defense systems, cell growth, and differentiation. We also investigate the impact of these systems' impairment in response to conventional chemotherapies and NOTCH inhibitors in silenced SCLC cell lines with different Kelch-like ECH-associated protein 1 (KEAP1) alterations. The KEAP1/NRF2 pathway is a master regulator of several redox-sensitive genes implicated in the resistance of tumor cells against therapeutic drugs. The dysfunction of the KEAP1/NRF2 system has been correlated with neoplastic patients' outcomes and responses to conventional therapies. In lung tumors, the growth and the progression of cancer cells may also involve the intersection between the molecular NRF2/KEAP1 axis and other pathways, including NOTCH, with implications for antioxidant protection, survival of cancer cells, and drug resistance to therapies. At present, the data concerning the mechanism of aberrant NRF2/NOTCH crosstalk as well as its genetic and epigenetic basis in SCLC are incomplete. To better clarify this point and elucidate the contribution of NRF2/NOTCH crosstalk deregulation in tumorigenesis of SCLC, we investigated genetic and epigenetic dysfunctions of the KEAP1 gene in a subset of SCLC cell lines. Moreover, we assessed its impact on SCLC cells' response to conventional chemotherapies (etoposide, cisplatin, and their combination) and NOTCH inhibitor treatments using DAPT, a γ-secretase inhibitor (GSI). We demonstrated that the KEAP1/NRF2 axis is epigenetically controlled in SCLC cell lines and that silencing of KEAP1 by siRNA induced the upregulation of NRF2 with a consequent increase in SCLC cells' chemoresistance under cisplatin and etoposide treatment. Moreover, KEAP1 modulation also interfered with NOTCH1, HES1, and DLL3 transcription. Our preliminary data provide new insights about the downstream effects of KEAP1 dysfunction on NRF2 and NOTCH deregulation in this type of tumor and corroborate the hypothesis of a cooperation of these two pathways in the tumorigenesis of SCLC. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this paper is to review the literature and compile promising and clinically relevant biomarkers in otolaryngology—head & neck surgery not related to autoimmune disorders. Study Design: Narrative review. Methods: PubMed and Google Scholar were queried using combined key words such as "biomarkers" and "otolaryngology." Additional queries were made with combined key words such as "biomarkers" and a particular subspecialty such as "rhinology" or "otology" to maximize yield of relevant titles. Subsequently, specific biomarkers identified, such as "beta-2 transferrin," were used as key words. Relevant titles were reviewed and selected for abstract review. Applicable abstracts were then selected for review of the full text. Results: Biomarkers currently in clinical use within the field of otolaryngology were included in this review. The compiled biomarkers were then detailed individually regarding their molecular characteristics, function, and clinical significance. Conclusions: The number of biomarkers in use in otolaryngology is rapidly expanding representing a new diagnostic modality for our field. This review defines the key biomarkers that are currently or likely to be soon translated into clinical use within the field of otolaryngology. The majority of these biomarkers are in the form of proteins such as beta-2 transferrin, thyroglobulin, and P16. Given their growing impact on diagnosis, management and surveillance of otolaryngologic disorders periodic surveys are needed for education and to guide further advances and applications of otolaryngologic biomarkers. [ABSTRACT FROM AUTHOR]

Lysyl oxidase-like 2 (LOXL2) is a Cu2+-dependent amine oxidase, and it catalyzes the oxidative deamination of the ε-amino group of Lys residues on elastin and collagen, which is critical for extracellular matrix modeling. Stability is an important property for protein and it directly affects the dynamics and function of protein, which strongly relates to the human health and disease. However, the stability of LOXL2 is not well defined, i.e., which residues are important for its stability is unclear. In this paper, protein stability of LOXL2 was calculated by four methods, viz. mCSM, PremPS, DeepDDG and FoldX. Our results indicate that 95 residues (key residues) are important for the stability of LOXL2, with the amount of 14, 13, 8, 11, 26 in domain 1, 2, 3, 4, 5, respectively, while 23 in the linker between domains. Among these key residues, the types (numbers) are Leu (24), Val (20), Ile (12), Trp (11), Phe (11), Tyr (6), Cys (6), Met (4) and Arg (1). Most of the key residues are hydrophobic (88 in 95), which is consistent with the fact that hydrophobic interaction is the main force in protein folding. Cys residues are paired to constitute disulfide bonds, which play an important role in the structure and function of LOXL2. In the discussion, we compare the results with experimental data, and use the free energy perturbation for verification, which prove the reliability of this work. Thus, this study provides important insight for the research of disease treatment targeting LOXL2. [ABSTRACT FROM AUTHOR]

Simple Summary: The silkworm has fascinated people all around the world for centuries due to numerous applications of by-products resulting from its metamorphosis. A decline has been noticed due to industrialization and some disease concerns; however, several reasons strengthen compelling arguments for keeping up this species. The most prevalent nutrients identified along silkworm rearing, from mulberry leaves up to larvae, pupae, and silk, are proteins. The biological value of protein is based on amino acids. The presence of other nutrients, especially fatty acids (n-3 family), vitamins, minerals, and polyphenols, along with the profile in amino acids, which are taken from mulberry leaves and metabolized by larvae and then transferred to pupae, strengthen the conviction according to which silkworm by-products have a great nutritional potential that is either comparable with fish meal or better than other aquaculture-specific feedstuffs. This paper aims to present deep knowledge about amino acids (classification, metabolism, occurrence, mechanisms, and potential functions) for silkworms and fish to further understand these species. The silkworm Bombyx mori, the second most varied group of insects, is a fascinating insect that belongs to the Lepidoptera species. We aimed to deepen our knowledge about the composition and significance of amino acids (AA) from the sericulture chain to fish. AAs are the most prevalent molecules throughout the growth process of silkworms. We described AAs classification, occurrence, metabolism, and functions. Online datasets revealed that the essential AAs (EAA) level in fish meal and silkworm pupae (SWP) is comparable. SWP have a high content of methionine and lysine, which are the principal limiting AAs in fish diets, indicating that SWP have nutritional potential to be added to fish diets. Additionally, an overview of the data analyzed displays that SWP have a higher protein efficiency ratio than fish meal, the classical protein-rich source (>1.19 times), and compared to soybean meal, the second-most preferred source of protein in aquaculture (>2.08 times), indicating that SWP can be considered effective for animal feeding. In this study, we provide an overview of the current knowledge concerning AAs, paying special emphasis to EAAs and explaining, to some extent, certain mechanisms and functions of these compounds, from mulberry leaves to larvae–pupae and fish diets. [ABSTRACT FROM AUTHOR]

This article discusses the role of Tula-Family Proteins in cell signaling and activation. The Tula-Family Proteins, also known as UBASH3A and UBASH3B, are a relatively novel vertebrate gene/protein family that have been the subject of research for the past 20 years. Both UBASH3A and UBASH3B possess protein tyrosine phosphatase (PTP) activity and suppress protein tyrosine kinase (PTK)-dependent cell signaling. However, they also have distinct differences in substrate specificity, optimal conditions for PTP activity, and tissue expression. UBASH3A has been linked to autoimmune diseases, while UBASH3B appears to be involved in Behcet's disease. The article also discusses the conservation of the UBASH3 family in vertebrates and the unique UBASH3 family found in teleosts. Several papers published in this special issue further explore the role of UBASH3A/B proteins in immunity, autoimmune conditions, platelets, and individual development. The review articles highlight the challenges in understanding this family despite two decades of research. [Extracted from the article]

Proteomics is a field dedicated to the analysis of proteins in cells, tissues, and organisms, aiming to gain insights into their structures, functions, and interactions. A crucial aspect within proteomics is protein family prediction, which involves identifying evolutionary relationships between proteins by examining similarities in their sequences or structures. This approach holds great potential for applications such as drug discovery and functional annotation of genomes. However, current methods for protein family prediction have certain limitations, including limited accuracy, high false positive rates, and challenges in handling large datasets. Some methods also rely on homologous sequences or protein structures, which introduce biases and restrict their applicability to specific protein families or structures. To overcome these limitations, researchers have turned to machine learning (ML) approaches that can identify connections between protein features and simplify complex high-dimensional datasets. This paper presents a comprehensive survey of articles that employ various ML techniques for predicting protein families. The primary objective is to explore and improve ML techniques specifically for protein family prediction, thus advancing future research in the field. Through qualitative and quantitative analyses of ML techniques, it is evident that multiple methods utilizing a range of classifiers have been applied for protein family prediction. However, there has been limited focus on developing novel classifiers for protein family classification, highlighting the urgent need for improved approaches in this area. By addressing these challenges, this research aims to enhance the accuracy and effectiveness of protein family prediction, ultimately facilitating advancements in proteomics and its diverse applications. [ABSTRACT FROM AUTHOR]

This research paper explores the qualitative analysis of protein samples using the Biuret reagent through microscale methods involving ceramic tiles, grooved tiles, and Eppendorf tubes. The study highlights the advantages of minimal reagent usage, reduced waste, and enhanced safety. The Biuret test is employed to detect peptide bonds indicative of protein presence. Protein concentrations used for the identity assay ranged from 0.1% to 1.0%. Protein was detected by all three methods compared; however, the Eppendorf method detected proteins at a concentration of 0.3% and above. The ceramic and grooved tiles could detect proteins from 0.4% and above, demonstrating that the Eppendorf method was more sensitive. The microscale adaptation of this traditional test is evaluated for its efficacy, precision, and practicality in various applications, particularly in educational and resource-limited laboratory settings. [ABSTRACT FROM AUTHOR]

Summary: Maize grain is deficient in lysine. While the opaque2 mutation increases grain lysine, o2 is a transcription factor that regulates a wide network of genes beyond zeins, which leads to pleiotropic and often negative effects. Additionally, the drastic reduction in 19 kDa and 22 kDa alpha‐zeins causes a floury kernel, unsuitable for agricultural use. Quality protein maize (QPM) overcame the undesirable kernel texture through the introgression of modifying alleles. However, QPM still lacks a functional o2 transcription factor, which has a penalty on non‐lysine amino acids due to the o2 mutation. CRISPR/cas9 gives researchers the ability to directly target genes of interest. In this paper, gene editing was used to specifically target the 19 kDa alpha zein gene family. This allows for proteome rebalancing to occur without an o2 mutation and without a total alpha‐zein knockout. The results showed that editing some, but not all, of the 19 kDa zeins resulted in up to 30% more lysine. An edited line displayed an increase of 30% over the wild type. While not quite the 55% lysine increase displayed by QPM, the line had little collateral impact on other amino acid levels compared to QPM. Additionally, the edited line containing a partially reduced 19 kDa showed an advantage in kernel texture that had a complete 19 kDa knockout. These results serve as proof of concept that editing the 19 kDa alpha‐zein family alone can enhance lysine while retaining vitreous endosperm and a functional O2 transcription factor. [ABSTRACT FROM AUTHOR]

In this work, we developed a microfluidic paper-based analytical device (μPAD) for the on-line isolation of proteins and the electrochemical detection of lead ions (Pb(II)) in urine samples. The patterned filter paper was prepared through the direct printing of microchannel patterns on filter paper using an office laser printer. The paper was modified with protein precipitant and was then coupled with a detachable three-electrode system. Experimental parameters, namely, modification reagents, microchannel length and width, deposition potential, and deposition time, were optimized. Then, the maximum protein concentration under which the device can function was obtained as 300 mg L−1. The linear range was 10–500 μg L−1 with a detection limit of 9 μg L−1. The effectiveness of this device was demonstrated through the quantification of Pb(II) in urine samples and the results agreed with those of atomic absorption spectrometry (AAS). • A simple electrochemical paper-based microfluidic device was built using laser printer and 3D printer. • The device enables on-line isolation of proteins in urine. • The maximum protein concentration under which the proposed device can function was 300 mg L−1. • Direct electrochemical detection of Pb in urine was achieved with a detection limit of 9 μg L−1. [ABSTRACT FROM AUTHOR]