Prenatal paraben exposure and atopic dermatitis‐related outcomes among children

Background: Parabens, widely used as preservatives in cosmetics, foods, and other consumer products, are suspected of contributing to allergy susceptibility. The detection of parabens in the placenta or amniotic fluid raised concerns about potential health consequences for the child. Recently, an increased asthma risk following prenatal exposure has been reported. Here, we investigated whether prenatal paraben exposure can influence the risk for atopic dermatitis (AD). Methods: 261 mother-child pairs of the German mother-child study LINA were included in this analysis. Eight paraben species were quantified in maternal urine obtained at gestational week 34. According to the parental report of physician-diagnosed AD from age 1 to 8 years, disease onset, and persistence, childhood AD was classified into four different phenotypes. Results: 4.6% (n = 12) and 12.3% (n = 32) of the children were classified as having very early-onset AD (until age two) either with or without remission, 11.9% (n = 31) as early-onset (after age two), and 3.1% (n = 8) as childhood-onset AD (after age six). Exposure to ethylparaben and n-butylparaben was associated with an increased risk to develop very early-onset AD without remission (EtP: adj.OR/95% CI:1.44/1.04-2.00,nBuP:adj.OR/95% CI:1.95/1.22-3.12). The effects of both parabens were predominant in children without a history of maternal AD and independent of children's sex. Conclusion: Prenatal EtP or nBuP exposure may increase children's susceptibility for persistent AD with disease onset at very early age. This association was particularly pronounced in children without a history of maternal AD, indicating that children without a genetic predisposition are more susceptible to paraben exposure

Particle-Based Microfluidic Quartz Crystal Microbalance (QCM) Biosensing Utilizing Mass Amplification and Magnetic Bead Convection

Microfluidic quartz crystal microbalances (QCM) can be used as powerful biosensors that not only allow quantifying a target analyte, but also provide kinetic information about the surface processes of binding and release. Nevertheless, their practical use as point-of-care devices is restricted by a limit of detection (LoD) of some ng/cm². It prohibits the measurement of small molecules in low concentrations within the initial sample. Here, two concepts based on superparamagnetic particles are presented that allow enhancing the LoD of a QCM. First, a particle-enhanced C-reactive protein (CRP) measurement on a QCM is shown. The signal response could be increased by a factor of up to five by utilizing the particles for mass amplification. Further, a scheme for sample pre-preparation utilizing convective up-concentration involving magnetic bead manipulation is investigated. These experiments are carried out with a glass device that is fabricated by utilizing a femtosecond laser. Operation regimes for the magnetic manipulation of particles within the microfluidic channel with integrated pole pieces that are activated by external permanent magnets are described. Finally, the potential combination of the concepts of mass amplification and up-concentration within an integrated lab-on-a chip device is discussed

Low-cost, in-liquid measuring system using a novel compact oscillation circuit and quartz-crystal microbalances (QCMs) as a versatile biosensor platform

Quartz-crystal microbalances (QCMs) are commercially available mass sensors which mainly consist of a quartz resonator that oscillates at a characteristic frequency, which shifts when mass changes due to surface binding of molecules. In addition to mass changes, the viscosity of gases or liquids in contact with the sensor also shifts the resonance but also influences the quality factor (Q-factor). Typical biosensor applications demand operation in liquid environments leading to viscous damping strongly lowering Q-factors. For obtaining reliable measurements in liquid environments, excellent resonator control and signal processing are essential but standard resonator circuits like the Pierce and Colpitts oscillator fail to establish stable resonances. Here we present a lowcost, compact and robust oscillator circuit comprising of state-of-the-art commercially available surface-mount technology components which stimulates the QCMs oscillation, while it also establishes a control loop regulating the applied voltage. Thereby an increased energy dissipation by strong viscous damping in liquid solutions can be compensated and oscillations are stabilized. The presented circuit is suitable to be used in compact biosensor systems using custom-made miniaturized QCMs in microfluidic environments. As a proof of concept we used this circuit in combination with a customized microfabricated QCM in a microfluidic environment to measure the concentration of C-reactive protein (CRP) in buffer (PBS) down to concentrations as low as 5 μgmL -1