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

Discrete wavelet analysis of the influence of the North Atlantic Oscillation on Baltic Sea level

Mean sea level (MSL) in the Baltic Sea is influenced by several factors and therefore presents a complex behaviour over a wide range of time-scales. This work performs a multi-scale analysis of MSL variability in the Baltic Sea using discrete wavelet analysis. The North Atlantic Oscillation (NAO) is well known for having a strong influence in MSL variability over the Baltic; however, the relationship between MSL and NAO at different time-scales is still little understood. In this work a comparison of MSL and NAO variability is performed for a wide range of temporal scales, uncovering distinct relationships in high-frequency and long-term temporal variability. The annual and sub-annual scales are found to account for more than 50% of the total MSL variability. The MSL annual cycle is analysed and a shift from low to high amplitude values is identified in the 1970s for most stations. MSL is found to be anti-correlated to NAO at short time-scales while on the long-term NAO and MSL appear to be positively correlated for most stations. The physical mechanisms behind these distinct relationships deserve deeper study

Supporting direct care workers in dementia care: effects of a psycho-educational intervention

YesAn experimental study using a pre-posttest control group design was conducted to assess the effects of a person-centred care based psycho-educational intervention on direct care workers’ stress, burnout and job satisfaction. The intervention aimed to develop person-centred care competences and tools for stress management. Four aged care facilities were randomly assigned to a psycho-educational or an education-only intervention (control). Data were collected from fifty-six direct care workers (female, mean age 44.72±9.02) through measurements of burnout (Maslach Burnout Inventory), job satisfaction (Minnesota Satisfaction Questionnaire-short form) and stress (Perceived Stress Scale) and focus-group interviews. Results showed significant positive effects in emotional exhaustion (p=0.029) and positive but no significant effects in stress and job satisfaction. According to qualitative data, the experimental group perceived enhanced group cohesion, emotional management and self-care awareness. Psycho-educational interventions may contribute to reduce direct care workers’ burnout. Further work is needed to determine the extent of its benefits.Portuguese Foundation for Science and Technolog

Person-centredness in direct care workers caring for residents with dementia: effects of a psycho-educational intervention

YesThis study assessed the effects of a psycho-educational intervention on direct care workers' person-centredness during morning care to residents with dementia. A controlled pretest–posttest study was conducted in four aged-care facilities with 56 direct care workers (female, mean age 44.72 ± 9.02). Two experimental facilities received a psycho-educational intervention comprising person-centred care competences and stress management skills; control facilities received an education-only intervention, without stress support. In total, 112 video-recorded morning care sessions were coded using the Global Behaviour Scale. Both groups reported significantly higher scores on eight of 11 items of the Global Behaviour Scale and on the Global Behaviour Scale total score at posttest (F=10.59; p=0.02). Global Behaviour Scale total score improvements were higher for the experimental group, with values close to significance (F=3.90; p=0.054). The findings suggest that a psycho-educational intervention may increase care workers' person-centredness. Further research is needed to explore the long-term sustainability and extent of its benefits on workers and residents.Foundation for Science and Technolog

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

River damming leads to decreased phytoplankton biomass and disappearance of cyanobacteria blooms

The large Alqueva dam was built in the early 2000s in the Guadiana River (southern Portugal) and has highly controlled the freshwater flowing into the Guadiana estuary, leading to significant changes in the natural hydrological regime. To evaluate the impacts of water restriction and flow regularization on estuarine phytoplankton and their environmental variables, sampling campaigns were conducted in the Guadiana estuary throughout a 14-year period, covering different phases related to the Alqueva dam construction. Significant alterations in phytoplankton and their environmental drivers were observed. In the post-filling period, river flow became more constant throughout the year and its natural seasonal variability, with maxima in the winter and minima in the summer, was greatly reduced, leading to higher river flows in the summer and lower in the winter, in relation to the pre-filling phase. Nutrient and light availability and, hence, phytoplankton dynamics, were greatly affected. Phytoplankton abundance and biomass decreased in the post-filling phase related to a decrease in diatoms and cyanobacteria. Since cyanobacteria blooms in the Guadiana are frequently dominated by toxic species, this constitutes an improvement in water quality. However, the overall decrease in phytoplankton biomass and, specifically, the decline in diatom biomass, will have major consequences for the higher trophic levels that depend on planktonic food

Antibody Surface Coverage Drives Matrix Interference in Microfluidic Capillary Immunoassays

The performance of biosensors is often optimised in buffers, which brings inconsistencies during applications with biological samples. Current strategies for minimising sample (matrix) interference are complex to automate and miniaturise, involving e.g. sample dilution or recovery of serum/plasma. This study shows the first systematic study using hundreds of actual microfluidic immunoassay fluoropolymer strips to understand matrix interference in microflow systems. As many interfering factors are assay-specific, we have explored matrix interference for a range of enzymatic immunoassays, including a direct mIgG/anti-mIgG, a sandwich cancer biomarker PSA and a sandwich inflammatory cytokine IL-1β. Serum matrix interference was significantly affected by capillary antibody surface coverage, suggesting for the first time the main cause of serum matrix effect is low-affinity serum components (e.g. auto-antibodies) competing with high-affinity antigen for the immobilised antibody. Additional experiments carried out with different capillary diameters confirmed the importance of antibody surface coverage in managing matrix interference. Building on these findings we propose a novel analytical approach where antibody surface coverage and sample incubation times are key for eliminating and/or minimising serum matrix interference, consisting in bioassay optimization carried out in serum instead of buffer, without compromising the performance of the bioassay nor adding extra cost nor steps. This will help establishing a new route towards faster development of modern point-of-care tests and effective biosensors development

Effects of a psycho-educational intervention on direct care workers’ communicative behaviours with residents with dementia

YesThis study assessed the effects of a person-centred care based psycho-educational intervention on direct care workers’ communicative behaviours with people with dementia living in aged care facilities. An experimental study with a pre-posttest control group design was conducted in four aged care facilities. Two experimental facilities received an eight-weekly psycho-educational intervention aiming to develop workers’ knowledge about dementia, person-centred care competences and tools for stress management; control facilities received an education-only, with no support to deal with stress. A total of 332 morning care sessions, involving fifty-six direct care workers (female, mean age 44.72±9.02), were video-recorded before and two weeks after the intervention The frequency and duration of a list of verbal and non-verbal communicative behaviours were analysed. Within the experimental group there was a positive change from pre to post-test on the frequency of all workers’ communicative behaviours. Significant treatment effects in favour of the experimental group were obtained for the frequency of inform (p<0.01, ƞ2partial=0.09) and laugh (p<0.01, ƞ2 partial=0.18). Differences between groups emerged mainly in relation to non-verbal communicative behaviours. The findings suggest that a person-centred care based psycho-educational intervention can positively affect the direct care workers’ communicative behaviours with residents with dementia. Further research is required to determine the extent of the benefits of this approach.Foundation for Science and Technolog

CH4 production at moderate H2/CO2 pressures insights on the use of anaerobic granular sludge as biocatalyst

Introduction: The continuous increase in energy consumption and the intensive use of fossil fuels, lead to the emission of greenhouse gases (GHG) and, in particular, to an increase in the concentration of CO2 in the atmosphere. In this context, the improvement in global awareness and the demand for sustainable technologies and products strongly contribute to laid plans to combat climate change. CO2-to-CH4 conversion represents a cutting-edge solution for CO2 capture and use, contributing to the reduction of GHG emission. Catalytic conversion of CO2-to-CH4 have been investigated, however, the high cost associated to the catalysts employed limits their use on a large scale. Biological CO2 methanation can overcome the significant technical and economic challenges of catalytic CO2 methanation. The biological production of CH4 using CO2-rich gases together with H2 is a promising strategy for the production of bioproducts. Hydrogenotrophic methanogens have a crucial role on the direct conversion of CO2+H2 into CH4, hence the importance to study the specific hydrogenotrophic methanogenic activity (SHMA). Methodology: In this work, the effect of initial substrate (H2/CO2) pressure, from 100 to 500 kPa, on the SHMA, on CH4 production rate and on developed microbial communities were evaluated. Two different pressurized bioreactors were studied using anaerobic granular sludge as the biocatalyst and H2/CO2 (80:20, v/v) as sole carbon and energy source. Gaseous compounds were analyzed by GC and archaeal diversity within granular sludge was monitored by 16S r-RNA based techniques. Results: The results showed an increase in the SHMA as well as in the CH4 production rate with the increase of the initial H2/CO2 pressure. This results are very interesting since no inhibitory effects were observed on the microbial activity, demonstrating the resistance of the anaerobic granular sludge. The Illumina results showed that Methanosarcinales, Methanobacteriales and Methanomicrobiales were the three orders that prevailed in the pressurized system, for all the pressures tested. However, hydrogenotrophic methanogens from Methanobacterium and Methanospirillum genera slightly increased their relative abundance, varying from 38% (100 kPa) to 41% (500 kPa) and from 8% (100 kPa) to 12% (500 kPa), respectively. Conclusions: In conclusion, the archaeal community seems to be very stable when submitted to increasing H2/CO2 pressures, highlighting the potential of the anaerobic granular sludge as an efficient microbial platform for the production of added-value compounds from gaseous carbon waste streams.Portuguese Foundation for Science and Technology (FCT): POCI-01-0145-FEDER-031377; strategic funding of UIDB/04469/2020 unit; BioTecNorte operation (NORTE-01-0145-FEDER-000004); FCT doctoral grant PD/BD/128030/2016.info:eu-repo/semantics/publishedVersio

CH4 production at moderate H2/CO2 pressures - insights on the specific hydrogenotrophic methanogenic activity

CO2 is one of the main contributors to greenhouse gases (GHGs), being its emission to the atmosphere one of the major driver of global climate change. Biological methanation of CO2 using renewable H2 provides a promising approach to use of superplus renewable electrical power to produce a gaseous fuel. CH4 is considered an important renewable energy carrier, that has a wide range of applications such as natural gas for distribution. Hydrogenotrophic methanogens are key elements in the CO2/H2 methanation process. Thus the importance to study the specific hydrogenotrophic methanogenic activity (SHMA). The effect of the initial substrate (H2/CO2) pressure on the SHMA was investigated in two different pressurized bioreactors. The results suggest that in addition to the increase of the initial substrate pressure, also the bioreactor configuration influence the SHMA, which is crucial for the success of biological CO2 methanation technologies but also in anaerobic bioreactors treating wastewaters.info:eu-repo/semantics/publishedVersio