Sensitive optical detection of clinically relevant biomarkers in affordable microfluidic devices: Overcoming substrate diffusion limitations

One of the biggest challenges in miniaturization of optical immunoassays is the short light path distance of microchannels/microcapillaries. Protein biomarkers are often presented in circulating blood in the picomolar-femtomolar range, requiring exceptional levels of sensitivity that cannot be met with traditional chromogenic substrates and without sophisticated, bulky detection systems. This study discloses an effective strategy for increasing the sensitivity and shorten the total test time for sandwich ELISAs in microfluidic devices optically interrogated, based on enhancing enzymatic amplification. We found that activity of Horseradish Peroxidase (HRP) in mesofluidic systems is highly limited by diffusion, therefore increasing the concentration of enzymatic substrate in these systems does not translate into an enhancement in enzymatic conversation. The opposite happens in microfluidic systems due to short diffusion distances, however increased concentration of the second enzymatic substrate, hydrogen peroxide (H 2O 2), leads to enzyme inhibition as herein reported. Consequently, we found that the molar ratio of o-phenylenediamine (OPD) to hydrogen peroxide from commercially substrate formulations is not suitable for miniaturized systems. Sandwich ELISA quantitation of a cancer biomarker PSA and human cytokine IL-1β in fluoropolymer microfluidic strips revealed over one order of magnitude increase in sensitivity and 10-fold decrease in incubation time by simply changing the molar ratio of OPD:H 2O 2 from 1:3 to 1:1 and increasing OPD concentration from 1 to 4 mg/ml. This enhancement in enzymatic amplification offers finally the sensitivity required for optical interrogation of novel portable and affordable microfluidic devices with inexpensive and ubiquitous smartphones and flatbed scanners. </p

A Lab-in-a-briefcase for rapid prostate specific antigen (PSA) screening from whole blood

We present a new concept for rapid and fully portable Prostate Specific Antigen (PSA) measurement, termed “Lab-in-a-Briefcase”, which integrates an affordable microfluidic ELISA platform utilising a melt-extruded fluoropolymer Micro Capillary Film (MCF) containing 10 bore, 200 μm internal diameter capillaries, a disposable multi-syringe aspirator (MSA) plus a sample tray pre-loaded with all required immunoassay reagents, and a portable film scanner for colorimetric signal digital quantitation. Each MSA can perform 10 replicate microfluidic immunoassays on 8 samples, allowing 80measurements to be made in less than 15 minutes based on semi-automated operation and norequirement of additional fluid handling equipment. An assay was optimised for measurement of a clinically relevant range of PSA from 0.9 to 60.0 ng/ml in 15 minutes with CVs in the order of 5% based on intra-assay variability when read using a consumer flatbed film scanner. The PSA assay performance in the MSA remained robust in the presence of undiluted or 1:2 diluted human serum or whole blood, and the matrix effect could simply be overcome by extending sample incubation times. The PSA "Lab-in-a-briefcase" is particularly suited to a low-resource health setting where diagnostic labs and automated immunoassay systems are not accessible, by allowing PSA measurement outside the laboratory using affordable equipment

Environmental risk assessment in a contaminated estuary: an integrated weight of evidence approach as a decision support tool

Environmental risk assessment of complex ecosystems such as estuaries is a challenge, where innovative and integrated approaches are needed. The present work aimed at developing an innovative integrative methodology to evaluate in an impacted estuary (the Sado, in Portugal, was taken as case study), the adverse effects onto both ecosystem and human health. For the purpose, new standardized lines of evidence based on multiple quantitative data were integrated into a weight of evidence according to a best expert judgment approach. The best professional judgment for a weight of evidence approach in the present study was based on the following lines of evidence: i) human contamination pathways; ii) human health effects: chronic disease; iii) human health effects: reproductive health; iv) human health effects: health care; v) human exposure through consumption of local agriculture produce; vi) exposure to contaminated of water wells and agriculture soils; vii) contamination of the estuarine sedimentary environment (metal and organic contaminants); viii) effects on benthic organisms with commercial value; and ix) genotoxic potential of sediments. Each line of evidence was then ordinally ranked by levels of ecological or human health risk, according to a tabular decision matrix and expert judgment. Fifteen experts scored two fishing areas of the Sado estuary and a control estuarine area, in a scale of increasing environmental risk and management actions to be taken. The integrated assessment allowed concluding that the estuary should not be regarded as impacted by a specific toxicant, such as metals and organic compounds hitherto measured, but by the cumulative risk of a complex mixture of contaminants. The proven adverse effects on species with commercial value may be used to witness the environmental quality of the estuarine ecosystem. This method argues in favor of expert judgment and qualitative assessment as a decision support tool to the integrative management of estuaries. Namely it allows communicating environmental risk and proposing mitigation measures to local authorities and population under a holistic perspective as an alternative to narrow single line of evidence approaches, which is mandatory to understand cause and effect relationships in complex areas like estuaries.info:eu-repo/semantics/publishedVersio

Fluorescence of a benzothienopyridopyrimidone in solution and in lipid vesicles

Fluorescence properties of a biologically active benzothienopyridopyrimidone in solution and in lipid vesicles are reported. Assays at different pH values (0.5–10) allowed the determination of pKa = 2.0, showing that this compound may be useful as a pH indicator for pH ≤ 4. In lipid vesicles, benzothienopyridopyrimidone locates in a water-rich environment, indicating that it can be carried in the hydrophilic region of liposomes for drug delivery applications.Fundação para a Ciência e a Tecnologia (FCT

Studies of encapsulation of new antitumoral fluorescent compounds in nanoliposomes for drug delivery purposes

This work was funded by Foundation for Science and Technology (FCT-Portugal) through CFUM, CQ-UM, Project PTDC/QUI/81238/2006 and Post-doc. grant of A.S. Abreu (SFRH/BPD/24548/2005)

Studies of encapsulation of a new potential antitumoral indole derivative in nanoliposomes for drug delivery applications

This work was funded by FCT-Portugal and FEDER through CFUM, CQ-UM, Project PTDC/QUI/81238/2006 and Post-doc. grant of A.S. Abreu (SFRH/BPD/ /24548/2005)

Nanoliposomes for encapsulation and delivery of the potential antitumoral methyl 6-methoxy-3-(4-methoxyphenyl)-1H-indole-2-carboxylate

[Excerpt] Nanoliposomes are new technological developments for the encapsulation and delivery of bioactive agents. Because of their biocompatibility and biodegradability, along with their size, nanoliposomes have potential applications in a vast range of fields, including nanotherapy. Nanoliposomes are able to enhance the performance of bioactive agents by improving their bioavailability, in vitro and in vivo stability, as well as preventing their unwanted interactions with other molecules [1]. Nanoliposomes may contain, in addition to phospholipids, other molecules such as cholesterol (Ch) which is an important component of most natural membranes. The incorporation of Ch can increase stability by modulating the fluidity of the lipid bilayer preventing crystallization of the phospholipid acyl chains and providing steric hindrance to their movement. Further advances in liposome research found that polyethylene glycol (PEG), which is inert in the body, allows longer circulatory life of the drug delivery system [2]. [...]This work was funded by FCT-Portugal and FEDER through CFUM, CQ-UM, Project PTDC/QUI/81238/2006 (cofinanced by FCT and by program FEDER/COMPETE, ref. FCOMP-01-0124-FEDER-007467) and Post-doc. grant of A.S. Abreu (SFRH/BPD/24548/2005)

Fluorescence studies of 2-quinolinones and coumarins including peptide derivatives in solution and in lipid membranes

Photophysical properties of 2-quinolinones and coumarins, including peptide derivatives, were determined. Fluorescence emission and anisotropy measurements of compounds incorporated in lipid vesicles were performed. Our studies indicate that these compounds may be used as fluorescent probes for peptides and lipid membranes.Fundação para a Ciência e a Tecnologia (FCT) and FEDER for financial support to the Research Centres, CFUM [PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER022711)] and CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)] and to the research project PTDC/QUI/81238/2006 (FCOMP01-0124-FEDER-007467). A.S. Abreu also thanks her post-doctoral grant (SFRH/BPD/24548/2005) to FCT, POPH-QREN, FSE

Nickel-based magnetoliposomes for delivery of new potential antitumor compounds

Publicado em "NN14 abstract book"Nickel-based nanoparticles were prepared and entrapped in liposomes, forming magnetoliposomes.The magnetoliposomes prepared were able to encapsulate new potential antitumor thienopyridine derivatives, showing to be promising for drug delivery applications.FCT and FEDER/COMPETE for Projects PEst-C/QUI/UI0686/2013, P-Est-C/FIS/UI0607/ /2013. n-STeP Project NORTE-07-0124-FEDER-000039 supported by the Region Operational Programme of the North of Portugal (ON.2). FCT and POPH/QREN/FSE for A.R.O.R. PhD grant (SFRH/BD/90949/2012)