A novel method for rapid and quantitative detection of bisphenol A in urine.

Bisphenol A (BPA) is classified as an endocrine disruptor (ED) and it can interact with variety of hormone receptors leading to hormonal disruption and increased risk of various adverse health effects. Reducing human exposure to BPA is one of the main challenges of public health, as it is constantly present in daily life. A low-cost and commonly applied method to enable determination of BPA in the patient's body has yet to be developed. Currently available techniques are expensive, time-consuming, and require access to highly equipped analytical chemistry laboratories. Here we describe a fast and cheap engineered lateral flow assay of our design, to detect of BPA in urine samples. The technology not only provides an opportunity to perform rapid medical diagnostics without the need for an access to the central laboratory but also a means for self-diagnosis by the patient. The addition of ß-glucuronidase improves the sensitivity of detection as it releases the free BPA from glucuronide complexes in urine. This invention may become a demonstrated analytical means for lowering human exposure to BPA and probably also to other EDs and consequently, may be useful in decrease of the risk for several lifestyle diseases.

Organosolv lignins as new stabilizers for cellulose nitrate: Thermal behavior and stability assessment.

Cellulose nitrate, commonly known as nitrocellulose (NC), and its corresponding propellants naturally decompose at normal conditions. To avoid early degradation, unexpected explosion, energy loss, and ensure a safe storage, stabilizing agents are often introduced within its compositions. Conventional stabilizers, such as aromatic amines like diphenylamine (DPA) and urea, can produce carcinogenic/toxic substances during propellants shelf life. Thus, a need for alternative stabilizing agents, which offer similar/better effectiveness and display a non/low toxicity, remains a challenge. This paper investigates the stabilizing effect of two organosolv lignins (OL), obtained from Aleppo pine (AP) and Eucalyptus globulus (EG), on NC. For this purpose, conventional stability tests and kinetic modeling are applied for different samples (S1-S4) using 3% of stabilizer, which are S1, pure NC; S2, NC + DPA; S3, NC + OL(AP); and S4, NC + OL(EG). Beforehand, FTIR spectroscopy and DSC analysis have been used to check the compatibility of these potential stabilizers and NC. The obtained results via Bergmann-Jung and vacuum stability tests suggested that the prepared mixtures are stable. The kinetic study based on DSC data using isoconversional methods shows that both stabilizers display a good stabilizing effect. The reactivity between the different organosolv lignins and NOx released during the degradation of NC has been well highlighted using FTIR and TGA analyses. Hence, these efficient, environmentally friendly and readily available substances can be effectively used as stabilizers for NC-based formulations.

It is all in the bag: collodion bag versus HistoGel cell block method.

INTRODUCTION: We performed a comparison of cell blocks prepared with the collodion bag and HistoGel to evaluate the ease of embedding and cutting, performance with low cellularity specimens, time and cost per specimen, and value to support immunohistochemistry and molecular diagnostics. MATERIALS AND METHODS: We processed 11 fresh, unfixed effusions using both the collodion bag and the HistoGel cell block preparation methods. Six immunohistochemistry stains were tested on 2 of the body fluids. DNA was extracted and quantified, and polymerase chain reaction cycle thresholds were evaluated from cell blocks prepared from 5 of the body fluids. The comparison parameters included embedding difficulty, cutting resistance, adequacy, cell yield, cell preservation, immunohistochemistry stain quality, DNA quantity, integrity, and purity. The time and cost to prepare each specimen was compared using normalized values for preparation of specimen, cost per year, and cost per specimen. RESULTS: Each parameter was assessed for both cell block preparation methods. All 3 of the samples with moderate or poor cell yield were low-volume (5-mL) samples prepared with the HistoGel method. In contrast, the collodion bag method produced a good yield with all three 5-mL samples. DNA recovery was greater in the collodion bag method. Similar crossing threshold values in purity reactions indicated equally high-quality matrix properties for the collodion bag and HistoGel preparations. Preparation of the specimen was 10 minutes faster with the collodion bag method, and the cost for the collodion bag method was $0.24 more expensive per cell block than using the HistoGel. CONCLUSIONS: The collodion bag method produced superior cell blocks for both morphologic and molecular studies more consistently, with lower volume specimens and with less time per specimen.

Development of an automated wax-printed paper-based lateral flow device for alpha-fetoprotein enzyme-linked immunosorbent assay.

In this study, a novel wax-printed paper-based lateral flow device has been developed as an alternative approach for an automated and one-step enzyme-linked immunosorbent assay (ELISA). The design pattern consisted of a non-delayed channel, a wax-delayed channel, a test zone and a control zone. This system was easily fabricated on a nitrocellulose membrane using a wax-printing method and then baked in an oven at 100°C for 1min. The four barriers of the wax-delayed channel could delay the flow time for 11s compared to the flow time of the non-delayed channel. To use the device under optimal conditions, alpha-fetoprotein (AFP) was detected at a limit of detection of 1ngmL-1 and assessed with the naked eye within 10min. A colorimetric intensity was also measured using a smart phone and computer software at a linear range of 0.1-100ngmL-1 with a good correlation. Furthermore, the proposed device was successfully applied to detect AFP in human serum. Therefore, the wax-printing demonstrates a user-friendly, easy and quick method for the fabrication of the device, which could be used as a one-step, portable, disposable, low-cost, simple, instrument-free and point-of-care device for the automated ELISA.

Point-of-care coagulation monitoring: first clinical experience using a paper-based lateral flow diagnostic device.

Vitamin K antagonists such as warfarin are the most widely used class of oral anticoagulants. Due to a narrow therapeutic window, patients on warfarin require regular monitoring. Self-testing using point-of-care (POC) diagnostic devices is available, but cost makes this monitoring method beyond reach for many. The main objective of this research was to assess the clinical utility of a low-cost, paper-based lateral flow POC diagnostic device developed for anticoagulation monitoring without the need for a separate electronic reader. Custom-fabricated lateral flow assay (LFA) test strips comprised of a glass fiber sample pad, a nitrocellulose analytical membrane, a cellulose wicking pad, and a plastic backing card were assembled in a plastic cassette. Healthy volunteers and patients on warfarin therapy were recruited for this prospective study. For each participant, a whole blood sample was collected via fingerstick to determine: (1) international normalized ratio (INR) using the CoaguChek® XS coagulometer, (2) hematocrit by centrifugation, and (3) red blood cell (RBC) travel distance on the experimental LFA device after 240 s using digital image analysis. RBC travel distance measured on the LFA device using blood samples obtained from warfarin patients positively correlated with increasing INR value and the LFA device had the capability to statistically distinguish between healthy volunteer INR values and those for patients groups with INR ≥ 2.6. From these data, it is predicted that this low-cost, paper-based LFA device can have clinical utility for identifying anticoagulated patients taking vitamin K antagonists who are outside of the desired therapeutic efficacy window.

Colorimetric stack pad immunoassay for bacterial identification.

A new colorimetric immunoassay concept, utilizing conventional lateral flow membranes (e.g., conjugation, sample, absorption and nitrocellulose), were placed in a different configuration in a stacking manner, where the liquid sample that may contain the analyte diffuses from the bottom to the upper-most layer. The key element of this proprietary technology is a capture layer, where a nitrocellulose membrane is modified with the target analyte of interest, namely in this study target Escherichia coli. During the immunoassay operation, samples contaminated with the target bacteria will conjugate to their corresponding HRP-antibodies laying in wait and the immune-target measurand complex flows by capillarity towards the upper-most layer to generate a colorimetric signal (positive answer) through an enzymatic reaction. In target-free samples, previously immobilized target bacteria on the capture layer will prevent the HRP-labeled anti-target antibodies from migrating to the upper-most layer, where the enzymatic substrate lays in wait. After optimization, the sensitivity of this approach was found to be 1,000 folds higher than ELISAs (102cellsmL-1). The advantages of the stacked pad assay include: miniaturization, operational simplicity, fast response time (less than 5min), useful sensitivity.

Safety Assessment of Nitrocellulose and Collodion as Used in Cosmetics.

The Cosmetic Ingredient Review Expert Panel (the Panel) assessed the safety of nitrocellulose and collodion as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration in cosmetic formulations. Both ingredients are used almost exclusively in nail product formulations. The maximum concentration of use of nitrocellulose in nail polish and enamels is 22%; for collodion, the maximum reported concentration of use in nail polish and enamel is 14%. The Panel reviewed available animal and clinical data in making its determination of safety.

Development of buffers for fast semidry transfer of proteins.

Western blot is an extensively used method for protein detection in cell biology. To optimize this procedure, here we examined a panel of buffers for their ability to efficiently transfer proteins from SDS-polyacrylamide gels onto nitrocellulose membranes in a short 12-min period, designated here as fast semidry transfer. Our results show for the first time that HEPES- and HEPPS/EPPS-based buffers represent the most efficient buffers for fast semidry transfer.

Multiplex lateral-flow test strips fabricated by two-dimensional shaping.

We have fabricated paper- and nitrocellulose-based lateral-flow devices that are shaped in two dimensions by a computer-controlled knife. The resulting star, candelabra, and other structures are spotted with multiple bioassay reagents to produce multiplex lateral-flow assays. We have also fabricated laminar composites in which porous nitrocellulose media are sandwiched between vinyl and polyester plastic films. This minimizes evaporation, protects assay surfaces from contamination and dehydration, and eliminates the need for the conventional hard plastic cassette holders that are typically used to package commercial lateral-flow diagnostic strips. The reported fabrication method is novel, low-cost, and well-suited to (i) fabrication and adoption in resource-poor areas, (ii) prototype development, (iii) high-volume manufacturing, and (iii) improving rates of operator error.

Preparation of (188) Re-labeled paper for treating skin cancer.

For homogeneous delivery of beta radiation to skin cancer, we developed a simple method for preparing (188) Re-labeled nitrocellulose paper. The homogeneity and stability of the labeled paper were investigated. Absorbed dose estimates were calculated using the Monte-Carlo method. A 74-MBq (188) Re-labeled paper with 1-cm diameter delivered 147.2 Gy up to 1-mm depth after 2-h irradiation. Animal experiments on tumor-bearing mice showed that 50 Gy is an adequate dose for treating skin cancer. Tumors disappeared 7 days after irradiation in all the groups irradiated by 50 or 100 Gy. The (188) Re-labeled paper provided a convenient, economical, effective, and non-invasive method of treating skin cancer.