This paper presents the performance of a passive planar rhombic micromixer with diamond-shaped obstacles and a rectangular contraction between the rhombi. The device was experimentally optimized using water for high mixing efficiency and a low pressure drop over a wide range of Reynolds numbers (Re = 0.1-117.6) by varying geometrical parameters such as the number of rhombi, the distance between obstacles and the contraction width. Due to the large amount of data generated, statistical methods were used to facilitate and improve the results of the analysis. The results revealed a rank of factors influencing mixing efficiency: Reynolds number > number of rhombi > contraction width > interobstacles distance. The pressure drop measured after three rhombi depends mainly on Re and interobstacle distance. The resulting optimum geometry for the low Re regime has a contraction width of 101 mu m and inter-obstacles distance of 93 mu m, while for the high Re regime a contraction width of 400 v and inter-obstacle distance of 121 mu m are more appropriate. These mixers enabled 80% mixing efficiency creating a pressure drop of 6.0 Pa at Re = 0.1 and 5.1 x 10(4) Pa at Re = 117.6, with a mixer length of 2.5 mu m. To the authors' knowledge, the developed mixer is one of the shortest planar passive micromixers reported to date.

Field-effect-based devices are becoming a basic structural element in a new generation of microbiosensors. Reliable molecular characterization of DNA and/or RNA is of paramount importance for disease diagnostics and to follow up alterations in gene expression profiles. The use of such devices for point-of-need diagnostics has been hindered by the need of standard or real-time PCR amplification procedures. The present work focuses on the development of a tantalum pentoxide (Ta2O5) based sensor for the real-time label free detection of DNA amplification via loop mediated isothermal amplification (LAMP) allowing for quantitative analysis of the cMYC proto-oncogene. The strategy based on the field effect sensor was tested within a range of 1 x 10(8)-10(11) copies of target DNA, and a linear relationship between the log copy number of the initial template DNA and threshold time was observed allowing for a semi-quantitative analysis of DNA template. The concept offers many of the advantages of isothermal quantitative real-time DNA amplification in a label free approach and may pave the way to point-of-care quantitative molecular analysis focused on ease of use and low cost.

Acrylamide is an amide used in several industrial applications making it easily discharged to aquatic ecosystems. The toxicity of acrylamide to aquatic organisms is scarcely known, although previous studies with murine models provided evidence for deleterious effects. To assess the effects of acrylamide to freshwater fish, goldfish (Carassius auratus L.) were exposed to several concentrations of waterborne acrylamide and analysed for genotoxic damage, alterations to detoxifying enzymes and histopathology. Results revealed a dose-dependent increase in total DNA strand breakage, the formation of erythrocytic nuclear abnormalities and in the levels of hepatic cytochrome P4501A (CYP1A) and glutathione S-transferase (GST) activity. In addition, acrylamide induced more histopathological changes to pancreatic acini than to the hepatic parenchyma, regardless of exposure concentration, whereas hepatic tissue only endured significant alterations at higher concentrations of exposure. Thus, results confirm the genotoxic potential of acrylamide to fish and its ability to induce CYP1A, probably as a direct primary defence mechanism. This strongly suggests the substance's pro-mutagenic potential in fish, similarly to what is known for rodents. However, the deleterious effects observed in the pancreatic acini, more severe than in the liver, could indicate a specific, albeit unknown toxic mechanism of acrylamide to fish that overran the organism's metabolic defences against a chemical agent rather than causing a general systemic failure.

Nanotechnology has provided a plethora of valuable tools that can be applied for the detection of biomolecules and analytes relevant for diagnosis purposes - nanodiagnostics. This surging new field of molecular diagnostics has been revolutionizing laboratory procedures and providing new ways to assess disease biomarkers with increased sensitivity. While most of the reported nanodiagnostics systems are proof-of-concepts that demonstrate their efficacy in the lab, several nanodiagnostics platforms have already matured to a level that open the way for effective translation to the clinics. Nanodiagnostics platforms (e.g., gold nanoparticles containing systems) have been remarkably useful for the development of molecular diagnosis strategies for DNA/RNA detection and characterization, including systems suitable for point-of-care. How near are nanodiagnostics to go from the bench to the bedside?

The increasing levels of drug resistance are one of biggest threats to overcome microbial infection. The ability to rapidly and accurately detect a given pathogen and its drug resistance profile is essential for the appropriate treatment of patients and for preventing further spread of drug-resistant strains. The predictive and informative value of these molecular markers needs to be translated into robust surveillance tools that correlate to the target and extent of resistance, monitor multiresistance and provide real time assessment at point-of-need. Rapid molecular assays for the detection of drug-resistance signatures in clinical specimens are based on the detection of specific nucleotide sequences and/or mutations within pre-selected biomarkers in the genome, indicative of the presence of the pathogen and/or associated with drug resistance. DNA and/or RNA based assays offer advantages over phenotypic assays, such as specificity and time from collection to result. Nanotechnology has provided new and robust tools for the detection of pathogens and more crucially to the fast and sensitive characterisation of molecular signatures of drug resistance. Amongst the plethora of nanotechnology based approaches, gold nanoparticles have prompt for the development of new strategies and platforms capable to provide valuable data at point-of-need with increased versatility but reduced costs. Gold nanoparticles, due to their unique spectral, optical and electrochemical properties, are one of the most widely used nanotechnology systems for molecular diagnostics. This review will focus on the use of gold nanoparticles for screening molecular signatures of drug resistance that have been reported thus far, and provide a critical evaluation of current and future developments of these technologies assisting pathogen identification and characterisation.

Antisense therapy is a powerful tool for post-transcriptional gene silencing suitable for down-regulating target genes associated to disease. Gold nanoparticles have been described as effective intracellular delivery vehicles for antisense oligonucleotides providing increased protection against nucleases and targeting capability via simple surface modification. We constructed an antisense gold-nanobeacon consisting of a stem-looped oligonucleotide double-labelled with 3′-Cy3 and 5′-Thiol-C6 and tested for the effective blocking of gene expression in colorectal cancer cells. Due to the beacon conformation, gene silencing was directly detected as fluorescence increases with hybridisation to target, which can be used to assess the level of silencing. Moreover, this system was extensively evaluated for the genotoxic, cytotoxic and proteomic effects of gold-nanobeacon exposure to cancer cells. The exposure was evaluated by two-dimensional protein electrophoresis followed by mass spectrometry to perform a proteomic profile and 3-(4,5-Dimethylthiazol-2- Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay, glutathione-S-transferase assay, micronucleus test and comet assay to assess the genotoxicity. This integrated toxicology evaluation showed that the proposed nanotheranostics strategy does not exhibit significant toxicity, which is extremely relevant when translating into in vivo systems.

Photocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the self-assembled silver nanoparticles incorporated in the cells’ back reflector.

Hypertrophic cardiomyopathy (HCM) is a primary disease of the cardiac muscle that occurs mainly due to mutations (>1,400 variants) in genes encoding for the cardiac sarcomere. HCM, the most common familial form of cardiomyopathy, affecting one in every 500 people in the general population, is typically inherited in an autosomal dominant pattern, and presents variable expressivity and age-related penetrance. Due to the morphological and pathological heterogeneity of the disease, the appearance and progression of symptoms is not straightforward. Most HCM patients are asymptomatic, but up to 25% develop significant symptoms, including chest pain and sudden cardiac death. Sudden cardiac death is a dramatic event, since it occurs without warning and mainly in younger people, including trained athletes. Molecular diagnosis of HCM is of the outmost importance, since it may allow detection of subjects carrying mutations on HCM-associated genes before development of clinical symptoms of HCM. However, due to the genetic heterogeneity of HCM, molecular diagnosis is difficult. Currently, there are mainly four techniques used for molecular diagnosis of HCM, including Sanger sequencing, high resolution melting, mutation detection using DNA arrays, and next-generation sequencing techniques. Application of these methods has proven successful for identification of mutations on HCM-related genes. This review summarizes the features of these technologies, highlighting their strengths and weaknesses. Furthermore, current therapeutics for HCM patients are correlated with clinically observed phenotypes and are based on the alleviation of symptoms. This is mainly due to insufficient knowledge on the mechanisms involved in the onset of HCM. Tissue engineering alongside regenerative medicine coupled with nanotherapeutics may allow fulfillment of those gaps, together with screening of novel therapeutic drugs and target delivery systems.

The TupABC system is involved in the cellular uptake of tungsten and belongs to the ABC (ATP binding cassette)-type transporter systems. The TupA component is a periplasmic protein that binds tungstate anions, which are then transported through the membrane by the TupB component using ATP hydrolysis as the energy source (the reaction catalyzed by the ModC component). We report the heterologous expression, purification, determination of affinity binding constants and crystallization of the Desulfovibrio alaskensis G20 TupA. The tupA gene (locus tag Dde_0234) was cloned in the pET46 Enterokinase/Ligation-Independent Cloning (LIC) expression vector, and the construct was used to transform BL21 (DE3) cells. TupA expression and purification were optimized to a final yield of 10 mg of soluble pure protein per liter of culture medium. Native polyacrylamide gel electrophoresis was carried out showing that TupA binds both tungstate and molybdate ions and has no significant interaction with sulfate, phosphate or perchlorate. Quantitative analysis of metal binding by isothermal titration calorimetry was in agreement with these results, but in addition, shows that TupA has higher affinity to tungstate than molybdate. The protein crystallizes in the presence of 30% (w/v) polyethylene glycol 3350 using the hanging-drop vapor diffusion method. The crystals diffract X-rays beyond 1.4 Å resolution and belong to the P2(1) space group, with cell parameters a = 52.25 Å, b = 42.50 Å, c = 54.71 Å, β = 95.43°. A molecular replacement solution was found, and the structure is currently under refinement.

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