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Hepatitis B virus (HBV) still remains a major global public health problem. One-half to one-third of the total HBV infected people died due to late detection of HBV. Serological antigen and viral HBV detections can help in the diagnosis, referral, and treatment of HBV. Available methods for HBV detection mostly used bulky instruments. Miniaturization of devices for HBV detection has been started by narrowing down the size of the devices. Several methods have also been proposed to increase the selectivity and sensitivity of the miniaturized methods, such as sandwich recognition of the biomarkers and the use of nano- to micro-sized materials. This review presents recent HBV detections in the last two decades from laboratory-based instruments towards microfluidic paper-based analytical devices (µPADs) for point-of-care testing (POCT) purposes. Early and routine analysis to detect HBV as early as possible could be achieved by POCT, especially for areas with limited access to a central laboratory and/or medical facilities.

Escherichia coli O157:H7 is a severe foodborne pathogen that causes lots of life-threatening diseases. In the search for a rapid, sensitive, portable and low-cost method to detect this pathogen, we developed a wax-printed paper-based enzyme-linked immunosorbent assay (P-ELISA) based on microfluidic paper-based analytical devices (μPADs), with the whole operation time being less than 3 h and only needing 5 μl samples for detection. The limit of detection (LOD) of E. coli O157:H7 reached 104 CFU ml-1, which is an order of magnitude higher than that of conventional ELISA (C-ELISA). The LOD in artificially contaminated beef samples is 1 CFU per 25 g after enriching the culture for 8 h. This method is superior to the molecular biology method in detection sensitivity and superior to C-ELISA and the national standard method in detection time and cost. Thus, the established P-ELISA method has good sensitivity, specificity and repeatability. It can be suitable for point-of-care testing without expensive and bulky instruments and can also provide a platform for detecting other pathogens, especially in areas that lack advanced clinical equipment.

The health risks associated with acute and prolonged exposure to estrogen receptor (ER) modulators has led to a concerted effort to identify and prioritize potential disruptors present in the environment. ER agonists and antagonists are identified with end-point assays, quantifying changes in cellular proliferation or gene transactivation in monolayers of estrogen receptor alpha expressing (ER+) cells upon exposure. While these monolayer cultures can be prepared, dosed, and analyzed in a highly parallelized manner, they are unable to predict the potencies of ER modulators in vivo accurately. Physiologically relevant model systems that better predict tissue- or organ-level responses are needed. To address this need, we describe here a screening platform capable of quantitatively assessing ER modulators in 96 chemically isolated 3D cultures. These cultures are supported in wax-patterned paper scaffolds whose design has improved performance and throughput over previously described paper-based setups. To highlight the potential of paper-based cultures for toxicity screens, we measured the potency of known ER modulators with a luciferase-based reporter assay. We also quantified the proliferation and invasion of two ER+ cell lines in the presence of estradiol. Despite the inability of the current setup to better predict in vivo potencies of ER modulators than monolayer cultures, the results demonstrate the potential of this platform to support increasingly complex and physiologically relevant tissue-like structures for environmental chemical risk assessment.

In this study, a paper-based microfluidic enzyme-linked immunosorbent assay (ELISA) was developed as a screening system for rapid detection of clenbuterol, which is illegally used as a growth promoter for food-producing animals. The microfluidic paper-based analytical device (μPAD) was combined with ELISA and the intrinsic properties of paper allowed the entrapment of antibody through cellulosic fibres, validating to be an alternative to 96-well ELISA microplate for food safety monitoring. Detection of clenbuterol in milk was achieved by measuring the intensity of colour change that was proportional to the analyte concentration with a detection limit of 0.2 ppb. The μPAD effectively reduces the cost, volume of reagents, and time required to run ELISA for food sample testing. usc Refereed/Peer-reviewed

Escherichia coli O157: H7 (E. coli O157: H7) has become one of the most dangerous foodborne pathogenic bacteria around the world. Currently, because of the tedious, high-cost and stringent laboratory conditions required, the conventional E. coli O157: H7 detection methods, such as culture-based methods and polymerase chain reaction (PCR), have much limitation. Thus, we developed a novel paper-based enzyme-linked immunosorbent assay (p-ELISA) with shorter operation duration, lower cost, relatively higher sensitivity and wider application. This method required less than 3 h and 5 μL of sample to complete the detection. The limit of detection (LOD) for E. coli O157: H7 reached 1 × 104 CFU/mL with high specificity. To be more suitable for on-site testing, the readout could be rapidly obtained without any expensive instruments. In this study, we chose E. coli O157:H7 as the representative, and our method could provide a platform for determination of other pathogenic bacteria.

Purpose: Dried blood spot (DBS) specimen simplifies blood collection, processing, storage and shipment and may reduce the cost of testing for hepatitis C virus (HCV) infection. We wanted to see if DBS using a cheap filter paper is reliable alternative to serum for detection of anti-HCV and HCV RNA. Materials and Methods: At a tertiary care hospital in Northeast India, we collected 91 paired DBS and serum specimens from patients at risk of HCV infection from July 2014 to June 2015. DBS was collected on Whatman No. 1 filter paper. After processing, the specimens were subjected to anti-HCV detection by a third-generation Enzyme-Linked Immunosorbent Assay (ELISA). The reactive DBS and serum specimens were further subjected to HCV RNA detection by polymerase chain reaction. The results were analysed in paired screen-positive study design. Results: Anti-HCV was detected in 9 (9.9%) DBS specimens and 10 (10.9%) serum specimens. There was statistically significant (P < 0.0001) correlation between the optical density values of DBS and serum specimens (Pearson r = 0.9181, 95% confidence interval: 0.8781–0.9453). HCV RNA was detected in 5/9 (55.6%) reactive DBS and 9/10 (90.0%) reactive serum specimens. There was no correlation between HCV RNA levels in the DBS and the serum specimens. The relative sensitivity rate and the relative false-positive rate of DBS anti-HCV ELISA were 0.89 and 1.00, respectively. Conclusions: DBS using Whatman No. 1 filter paper is quite reliable as serum for detection of anti-HCV. It can be useful in effective surveillance. However, it is not suitable for confirmation of chronic HCV infection.

This paper describes enzyme-linked immunosorbent assays (ELISAs) utilizing microfluidic thread/paper-based analytical devices (μTPAD), microfluidic fabric-based analytical devices (μFAD), and microfluidic thread-based analytical devices (μTAD). Here, the quantitative detection of biotinylated goat anti-mouse IgG (system one) and rabbit IgG (system two) antibodies via colorimetric analysis is detailed. In both systems, antibody is spotted on the detection site and subjected to a series of washes, addition of streptavidin-alkaline phosphatase (Strep-ALP) (system 1) or alkaline phosphatase (ALP)-conjugated secondary antibody (system 2), and colorimetric substrate. The devices are scanned and analyzed yielding a correlation between inverse yellow (or purple) intensity. For system one, a linear range of detection at low concentrations of streptavidin-alkaline phosphatase (Strep-ALP) was observed befire the enzyme reached a Vmax . At higher concentrations of Strep-ALP, saturation is achieved for both the μTPAD and μFAD devices. For system two, the IC50 values obtained for the non-trifurcated and trifurcated μTADs were determined to be 180.2 fmol/zone and 133.8 fmol/zone, respectively. The IC50 value was demonstrated to be 1034 fmol/zone and 208.6 fmol/zone for the μTPADs and μFADs, respectively. For all devices the lowest concentration of Strep-ALP or rabbit IgG used in the assay was 3.75 × 10-4 mg/mL and 0.7 fmol/zone, respectively. The development of this technology should further facilitate the use of these platforms for ELISA to detect and quantitate antibodies.

Washing is a standard step for enzyme-linked immunosorbent assays (ELISA) performed on a paper-based chip, in which nonspecific-binding antibodies and antigens should be removed completely from the paper surface. In this study, a novel three-dimensional (3D) washing strategy using a heating ring-oven was carried out on a paper-based chip. Compared with a plane washing mode by a ring-oven, this 3D washing strategy obtained a lower background, as gravity played an important role in the washing step. The paper-based chip was placed on a 3D plastic holder and the waste area was connected to a heating ring. Use of a heating waste area meant that the nonspecific-binding protein was continuously carried to the waste area through gravity and capillary action. The angle between the plastic holder and the ring plane was carefully selected. The effect of washing on different parts of the detection area was investigated by upconversion fluorescence and chemiluminescence (CL). This novel 3D washing strategy was performed for carcinoembryonic antigen detection through CL and a lower detection limit of 2 pg ml-1 was obtained. This approach provides an effective washing strategy to remove nonspecific-binding antibody from a paper-based immunodevice.

Mycotoxins and pesticides are prevalent in cereal food. It is difficult to detect these two kinds of hazard factors simultaneously in rapid assay. In order to find a solution to the problem, carbamates and aflatoxins were selected in this study to establish a rapid, on-site, and quantitative paper sensor. Two novel monoclonal antibodies (mAbs) against carbaryl and carbofuran (1D2 and G11) were developed. The IC50 values (half maximal inhibitory concentration) were 0.8 ng/mL and 217.6 ng/mL for carbaryl and carbofuran, respectively. Based on the sensitive and specific mAbs, a multi-TRFICA (time-resolved fluorescence) paper sensor was developed, which simultaneously detected six types of hazardous chemicals, including AFB1, AFB2, AFG1, AFG2, carbaryl, and carbofuran. A universal sample pretreatment method for mycotoxins and pesticides was explored to apply on established competitive indirect enzyme-linked immunosorbent assay (icELISA) and multi-TRFICA-paper sensor. The established paper sensor can be easily observed with naked eyes, qualitatively under a UV lamp, and quantitated using a home-made device. It exhibited a calculated limit of quantity for AFTs, carbaryl, and carbofuran of 0.03, 0.02, and 60.2 ng/mL in corn samples, respectively. The spiking-recoveries and real sample studies proved that multi-TRFICA-paper sensor is an accurate, sensitive, and high throughput detection method for simple and low-cost analysis in corn samples.

EVs/exosomes are considered as the next generation of biomarkers, including for liquid biopsies. Consequently, the quantification of EVs/exosomes is crucial for facilitating EV/exosome research and applications. Paper-based enzyme-linked immunosorbent assay (p-ELISA) is a portable diagnostic system with low cost that is simple and easy to use; however, it shows low sensitivity and linearity. In this study, we develop p-ELISA for targeting EVs/exosomes by using streptavidin agarose resin-based immobilization (SARBI). This method reduces assay preparation times, provides strong binding, and retains good sensitivity and linearity. The time required for the total assay, including preparation steps and surface immobilization, was shortened to ∼2 h. We evaluated SARBI p-ELISA systems with/without CD63 capture Ab and then with fetal bovine serum (FBS) and EVs/exosome-depleted fetal bovine serum (dFBS). The results provide evidence supporting the selective capture ability of SARBI p-ELISA. We obtain semiquantitative p-ELISA results using an exosome standard (ES) and human serum (HS), with R2 values of 0.95 and 0.92, respectively.

The fast and precise detection of potential allergen-specific immunoglobulin E (sIgE) is imperative for the diagnosis and appropriate treatment of allergic diseases. In this study, we have successfully fabricated a novel paper-based immunoassay device for the detection of sIgE in allergic diseases. We used Can f 1, one of the main dog allergens, as a model allergen to detect sIgE in human sera. To achieve excellent performance, the experimental parameters were optimized. Further, we extended this device for potential applications in the clinical diagnosis of allergic diseases: worthwhile clinical performance in the detection of allergens was achieved as compared to that achieved by commercial enzyme-linked immunosorbent assay (ELISA) kit. Therefore, it was proven that this strategy has the advantages of high-throughput, rapid, sensitive, and highly accurate detection of trace amounts of sIgEs. Furthermore, by simply changing the antigen and antibody, this device could be used for the high-throughput detection of other allergens, so as to achieve multiallergen detection and appropriate desensitization therapy, thereby making it promising in the determination of allergic diseases in clinics.

International audience; The incidence of arbovirus infections has increased dramatically in recent decades, affecting hundreds of millions of people each year. The Togaviridae family includes the chikungunya virus (CHIKV), which is typically transmitted by Aedes mosquitoes and causes a wide range of symptoms from flu-like fever to severe arthralgia. Although conventional diagnostic tests can provide early diagnosis of CHIKV infections, access to these tests is often limited in developing countries. Consequently, there is an urgent need to develop efficient, affordable, simple, rapid, and robust diagnostic tools that can be used in point-of-care settings. Early diagnosis is crucial to improve patient management and to reduce the risk of complications. A glass-fiber laser-cut microfluidic device (paper-based analytical device [PAD]) was designed and evaluated in a proof of principle context, for the analysis of 30 µL of patient serum. Biological raw materials used for the functionalization of the PAD were first screened by MAC-ELISA (IgM capture enzyme-linked immunosorbent assay) for CHIKV Immunoglobulin M (IgM) capture and then evaluated on the PAD using various human samples. Compared with viral lysate traditionally used for chikungunya (CHIK) serology, CHIKV pseudo-particles (PPs) have proven to be powerful antigens for specific IgM capture. The PAD was able to detect CHIKV IgM in human sera in less than 10 minutes. Results obtained in patient sera showed a sensitivity of 70.6% and a specificity of around 98%. The PAD showed few cross-reactions with other tropical viral diseases. The PAD could help health workers in the early diagnosis of tropical diseases such as CHIK, which require specific management protocols in at-risk populations.

Airborne influenza viruses are responsible for serious respiratory diseases, and most detection methods for airborne viruses are based on extraction of nucleic acids. Herein, vertical-flow-assay-based electrochemical paper immunosensors were fabricated to rapidly quantify the influenza H1N1 viruses in air after sampling with a portable electrostatic particle concentrator (EPC). The effects of antibodies, anti-influenza nucleoprotein antibodies (NP-Abs) and anti-influenza hemagglutinin antibodies (HA-Abs), on the paper sensors as well as nonpulsed high electrostatic fields with and without corona charging on the virus measurement were investigated. The antigenicity losses of the surface (HA) proteins were caused by H2O2 via lipid oxidation-derived radicals and 1O2 via direct protein peroxidation upon exposure of a high electrostatic field. However, minimal losses in antigenicity of NP of the influenza viruses were observed, and the concentration of the H1N1 viruses was more than 160 times higher in the EPC than the BioSampler upon using NP-Ab based paper sensors after 60 min collection. This NP-Ab-based paper sensors with the EPC provided measurements comparable to quantitative polymerase chain reaction (qPCR) but much quicker, specific to the influenza H1N1 viruses in the presence of other airborne microorganisms and beads, and more cost-effective than enzyme-linked immunosorbent assay and qPCR.

The enzyme-linked immunosorbent assay (ELISA) is one of the most commonly implemented clinical diagnostic tools for the detection and quantification of protein biomarkers. However, conventional ELISA tests require sophisticated infrastructure, expensive reagents, long assay time, and expertise for operation, which are not often easily accessible in resource-limited settings. Microfluidic ELISA-chip based point-of-care (POC) testing allows miniaturization and integration of complex functions that facilitate their usage in limited-resource settings. The current work demonstrates a simple, portable, low cost and equipment-free paper/poly(methyl methacrylate) (PMMA) integrated microfluidic ELISA-chip as a POC device with a visual distance-based readout for quantitative detection of clinical biomarkers. The integrated paper/PMMA ELISA-chip utilizes the movement of immunoassay complexes with magnetic beads by a permanent magnet in a PMMA part of the compartment. The target concentration is translated into a visual distance signal readout for quantitative detection of biomarkers in a μPAD. Because it does not require sophisticated instruments and has the added advantages of low cost, easy operation, and disposability with quantitative visual readout, the paper/PMMA ELISA-chip holds great promise for portable detection of target bioanalytes as a POC diagnostic tool in resource-limited setups.

Interest in low-cost diagnostic devices has recently gained attention, in part due to the rising cost of healthcare and the need to serve populations in resource-limited settings. A major challenge in the development of such devices is the need for hydrophobic barriers to contain polar bio-fluid analytes. Key approaches in lowering the cost in diagnostics have centered on (i) development of low-cost fabrication techniques/processes, (ii) use of affordable materials, or, (iii) minimizing the need for high-tech tools. This communication describes a simple, low-cost, adaptable, and portable method for patterning paper and subsequent use of the patterned paper in diagnostic tests. Our approach generates hydrophobic regions using a ball-point pen filled with a hydrophobizing molecule suspended in a solvent carrier. An empty ball-point pen was filled with a solution of trichloro perfluoroalkyl silane in hexanes (or hexadecane), and the pen used to draw lines on Whatman® chromatography 1 paper. The drawn regions defined the test zones since the trichloro silane reacts with the paper to give a hydrophobic barrier. The formation of the hydrophobic barriers is reaction kinetic and diffusion-limited, ensuring well defined narrow barriers. We performed colorimetric glucose assays and enzyme-linked immuno-sorbent assay (ELISA) using the created test zones. To demonstrate the versatility of this approach, we fabricated multiple devices on a single piece of paper and demonstrated the reproducibility of assays on these devices. The overall cost of devices fabricated by drawing are relatively lower (

Amphimeriasis, a fish-borne zoonotic disease caused by the liver fluke Amphimerus spp., has recently been reported as an emerging disease affecting an indigenous Ameridian group, the Chachi, living in Ecuador. The only method for diagnosing amphimeriasis was the microscopic detection of eggs from the parasite in patients' stool samples with very low sensitivity. Our group developed an ELISA technique for detection of anti-Amphimerus IgG in human sera and a molecular method based on LAMP technology (named LAMPhimerus) for specific and sensitive parasite DNA detection. The LAMPhimerus method showed to be much more sensitive than classical parasitological methods for amphimeriasis diagnosis using human stool samples for analysis. The objective of this work is to demonstrate the feasibility of using dried stool samples on filter paper as source of DNA in combination with the effectiveness of our previously designed LAMPhimerus assay for successfully Amphimerus sp. detection in clinical stool samples. A total of 102 untreated and undiluted stool samples collected from Chachi population were spread as thin layer onto common filter paper for easily transportation to our laboratory and stored at room temperature for one year until DNA extraction. When LAMPhimerus method was applied for Amphimerus sp. DNA detection, a higher number of positive results was detected (61/102; 59.80%) in comparison to parasitological methods (38/102; 37.25%), including 28/61 (45.90%) microscopy-confirmed Amphimerus sp. infections. The diagnostic parameters for the sensitivity and specificity werecalculated for our LAMPhimerus assay, which were 79.17% and 65.98%, respectively. We demonstrate, for the first time, that common filter paper is useful for easy collection and long-term storage of human stool samples for later DNA extraction and molecular analysis of human-parasitic trematode eggs. This simple, economic and easily handling method combined with the specific and sensible LAMPhimerus assay has the potential to beused as an effective molecular large-scale screening test for amphimeriasis-endemic areas.

An integrated origami paper-based analytical device (oPAD) based on competitive enzyme-linked immunosorbent assay (ELISA) was developed for testosterone (TES) detection. In this design, a positive correlation between the signals and analytes was observed due to the connection of the reaction zone and signal readout zone by a "detachable bridge". The device displayed rapid (35 min), sensitive (LOD: 1 μg L

Staphylococcus aureus is a frequent pathogenic bacterium that has a significant detrimental influence on the health of the human body. Therefore, developing a practical and portable detection platform is critical to ensuring food safety. Nanozymes are a kind of engineered nanomaterials with superior enzyme-like activities, providing infinite possibilities for the development of highly sensitive analytical assays. In this study, mesoporous core-shell palladium@platinum (Pd@Pt) nanozymes were synthesized and then applied as a signal amplifier in Staphylococcus aureus colorimetric immunoassay. At the same time, a careful comparative study of the catalytic performance with natural horseradish peroxidase (HRP), Pd@Pt nanozymes and their complexes Pd@Pt-HRP (HRP coupling with Pd@Pt nanozymes) were firstly performed, as well as clever using a colorimeter to achieve portable signal output. Pd@Pt-HRP bioprobes enable remarkable peroxidase-like catalytic activity, resulting in the highest sensitivity with a limit of detection (LOD) improved from 1 × 10

Infectious diseases are among the leading causes of mortality worldwide. A new coronavirus named severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) was identified in Wuhan, China in 2019, and the World Health Organization (WHO) declared its outbreak, coronavirus disease 2019 (COVID-19), as a global pandemic in 2020. COVID-19 can spread quickly from person to person. One of the most challenging issues is to identify the infected individuals and prevent potential spread of SARS-CoV-2. Recently, anti-SARS-CoV-2 immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody tests using immunochromatographic methods have been used as a complement to current detection methods and have provided information of the approximate course of COVID-19 infection. However, blood sampling causes pain and poses risks of infection at the needle puncture site. In this study, a novel patch sensor integrating porous microneedles and an immunochromatographic assay (PMNIA) was developed for the rapid detection of anti-SARS-CoV-2 IgM/IgG in dermal interstitial fluid (ISF), which is a rich source of protein biomarkers, such as antibodies. Biodegradable porous microneedles (MNs) made of polylactic acid were fabricated to extract ISF from human skin by capillary effect. The extracted ISF was vertically transported and flowed into the affixed immunoassay biosensor, where specific antibodies could be detected colorimetrically on-site. Anti-SARS-CoV-2 IgM/IgG antibodies were simultaneously detected within 3 min in vitro. Moreover, the limit of detection of anti-SARS-CoV-2 IgM and IgG concentrations was as low as 3 and 7 ng/mL, respectively. The developed device integrating porous MNs and immunochromatographic biosensors is expected to enable minimally invasive, simple, and rapid anti-SARS-CoV-2 IgM/IgG antibody testing. Furthermore, the compact size of the MN and biosensor-integrated device is advantageous for its widespread use. The proposed device has great potential for rapid screening of various infectious diseases in addition to COVID-19 as an effective complementary method with other diagnostic tests.

A multilayered paper-based platform is used to investigate the interactions between human lung tumor cells and fibroblasts that are isolated from primary patient tumor samples.

This paper addresses a growing need in clinical diagnostics for parallel, multiplex analysis of biomarkers from small biological samples. It describes a new procedure for assembling arrays of ssDNA and proteins on paper. This method starts with the synthesis of DNA oligonucleotides covalently linked to paper and proceeds to assemble microzones of DNA-conjugated paper into arrays capable of simultaneously capturing DNA, DNA-conjugated protein antigens, and DNA-conjugated antibodies. The synthesis of ssDNA oligonucleotides on paper is convenient and effective with 32% of the oligonucleotides cleaved and eluted from the paper substrate being full-length by HPLC for a 32-mer. These ssDNA arrays can be used to detect fluorophore-linked DNA oligonucleotides in solution, and as the basis for DNA-directed assembly of arrays of DNA-conjugated capture antibodies on paper, detect protein antigens by sandwich ELISAs. Paper-anchored ssDNA arrays with different sequences can be used to assemble paper-based devices capable of detecting DNA and antibodies in the same device and enable simple microfluidic paper-based devices.

Escherichia coli is a generic indicator of fecal contamination, and certain serotypes cause food- and water-borne illness such as O157:H7. In the clinic, detection of bacteriuria, which is often due to E. coli, is critical before certain surgical procedures or in cases of nosocomial infection to prevent further adverse events such as postoperative infection or sepsis. In low- and middle-income countries, where insufficient equipment and facilities preclude modern methods of detection, a simple, low-cost diagnostic device to detect E. coli in water and in the clinic will have significant impact. We have developed a simple paper-based colorimetric platform to detect E. coli contamination in 5h. On this platform, the mean color intensity for samples with 10(5)cells/mL is 0.118±0.002 (n=4), and 0.0145±0.003 (P

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.

High-sensitivity C-reactive protein (hs-CRP) has been regarded as a risk predictor of cardiovascular disease (CVD). Despite there are many methods to detect hs-CRP, quantitative, rapid, convenient, multiplex and highly sensitive measurement of it is still a challenge for point-of-care applications. In this study, we developed a paper-based ELISA to detect hs-CRP and the sensitive chemiluminescence was applied as detection signal. In this developed assay method, CRP concentration and chemiluminescence intensity were linearly correlated (r = 0.999) with a limit of detection (LOD) as low as 0.49 ng mL−1, which was comparable to that of conventional ELISA and superior to most of the current reported POCT methods for detection of hs-CRP. The precision of the assay was confirmed for low coefficient of variations, less than 7% for intra-assay and less than 10% for inter-assay. In clinical sample analysis, the results of hs-CRP detected by this assay were in good accordance with which obtained by commercial high sensitivity ELISA kit for in vitro diagnosis (r = 0.975). This assay required only 4 μL of sample and could be finished in less than 30 min. It may therefore be employed as a rapid pre-screening tool to identify patients with elevated risk of CVD.

To establish rapid, high-sensitive, quantitative detection of ACP residues in vegetables. A 1G2 cell clone was selected as the most sensitive for anti-ACP antibody production following secondary immunization, cell fusion, and screening. The affinity of the 1G2 antibody to each of the four coating agents (imidacloprid–bovine serum albumin [BSA], thiacloprid–BSA, imidaclothiz–BSA, and ACP-BSA) was determined using a 20 min enzyme-linked immunosorbent assay (ELISA). The half maximal inhibitory concentration (IC50) was 0.51–0.62 ng/mL, showing no significant difference in affinity to different antigens. However, we obtained IC50 values of 0.58 and 1.40 ng/mL on the linear regression lines for 1G2 anti-ACP antibody/imidacloprid–BSA and 1G2 anti-ACP antibody/thiacloprid–BSA, respectively, via quantum dot (QD)-based immunochromatography. That is, the 1G2 antibody/imidacloprid–BSA pair (the best combination) was about three times more sensitive than the 1G2 antibody/thiacloprid–BSA pair in immunochromatographic detection. The best combination was used for the development of an 8 min chromatographic paper test. With simple and convenient sample pretreatment, we achieved an average recovery of 75–117%. The coefficient of variation (CoV) was