Silicon Nitride-Based Micro-Apertures Coated with Parylene for the Investigation of Pore Proteins Fused in Free-Standing Lipid Bilayers.

In this work, we present a microsystem setup for performing sensitive biological membrane translocation measurements. Thin free-standing synthetic bilayer lipid membranes (BLM) were constructed in microfabricated silicon nitride apertures (<100 µm in diameter), conformal coated with Parylene (Parylene-C or Parylene-AF4). Within these BLMs, electrophysiological measurements were conducted to monitor the behavior of different pore proteins.

Thresholds of Endoglin Expression in Endothelial Cells Explains Vascular Etiology in Hereditary Hemorrhagic Telangiectasia Type 1.

Hereditary Hemorrhagic Telangiectasia type 1 (HHT1) is an autosomal dominant inherited disease characterized by arteriovenous malformations and hemorrhage. HHT1 is caused by mutations in , which encodes an ancillary receptor for Transforming Growth Factor-β/Bone Morphogenetic Protein-9 expressed in all vascular endothelial cells. Haploinsufficiency is widely accepted as the underlying mechanism for HHT1.

Systematic comparison of the male reproductive tract in fetal and adult Wistar rats exposed to DBP and DINP in utero during the masculinisation programming window.

This study investigates possible effects of in utero exposure of rats to a low dose (125 mg/kg bw/day) and a high dose (750 mg/kg bw/day) of Diisononyl phthalate (DINP) during the masculinisation programming window (MPW) which is embryonic days 15.5-18.5 (e15.

Rapid lipid bilayer membrane formation on Parylene coated apertures to perform ion channel analyses.

We present a chip design allowing rapid and robust lipid bilayer (LBL) membrane formation using a Parylene coated thin silicon nitride aperture. After bilayer formation, single membrane channels can be reconstituted and characterized by electrophysiology. The ability for robust reconstitution will allow parallelization and enhanced screening of small molecule drugs acting on or permeating across the membrane channel.

Publisher Correction: Dibutyl phthalate induced testicular dysgenesis originates after seminiferous cord formation in rats.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Optimization of on-chip bacterial culture conditions using the Box-Behnken design response surface methodology for faster drug susceptibility screening.

Optimized culture conditions are essential for the investigation of biological processes. In this work, on-chip optimization of bacterial culture conditions by combining microfluidics with the Box-Behnken design response surface methodology is presented. With this methodology, the effects of several cultivation variables and their interactions were investigated enabling very fast drug susceptibility screening.

PDMS-free microfluidic cell culture with integrated gas supply through a porous membrane of anodized aluminum oxide.

Microfluidic cell cultures are often used in academic research but only rarely in pharmaceutical research because of unsuitable designs, inappropriate choice of materials or incompatibility with standard equipment. In particular, microfluidic cell cultures to control the gaseous microenvironment rely on PDMS despite its disadvantages. We present a novel concept for such a cell culture device that addresses these issues and is made out of hard materials instead of PDMS.

3D Printing Solutions for Microfluidic Chip-To-World Connections.

The connection of microfluidic devices to the outer world by tubes and wires is an underestimated issue. We present methods based on 3D printing to realize microfluidic chip holders with reliable fluidic and electric connections. The chip holders are constructed by microstereolithography, an additive manufacturing technique with sub-millimeter resolution.

Effects of Exposure to Acetaminophen and Ibuprofen on Fetal Germ Cell Development in Both Sexes in Rodent and Human Using Multiple Experimental Systems.

Background: Analgesic exposure during pregnancy may affect aspects of fetal gonadal development that are targeted by endocrine disruptors.

Objectives: We investigated whether therapeutically relevant doses of acetaminophen and ibuprofen affect germ cell (GC) development in human fetal testes/ovaries using and xenograft approaches.

Methods: First-trimester human fetal testes/ovaries were cultured and exposed to acetaminophen or ibuprofen (7 d).

Microfluidic Platform for the Long-Term On-Chip Cultivation of Mammalian Cells for Lab-On-A-Chip Applications.

Lab-on-a-Chip (LoC) applications for the long-term analysis of mammalian cells are still very rare due to the lack of convenient cell cultivation devices. The difficulties are the integration of suitable supply structures, the need of expensive equipment like an incubator and sophisticated pumps as well as the choice of material. The presented device is made out of hard, but non-cytotoxic materials (silicon and glass) and contains two vertical arranged membranes out of hydrogel.

Dibutyl phthalate induced testicular dysgenesis originates after seminiferous cord formation in rats.

Administration of dibutyl phthalate (DBP) to pregnant rats causes reproductive disorders in male offspring, resulting from suppression of intratesticular testosterone, and is used as a model for human testicular dysgenesis syndrome (TDS). DBP exposure in pregnancy induces focal dysgenetic areas in fetal testes that appear between e19.5-e21.

Experimentally induced testicular dysgenesis syndrome originates in the masculinization programming window.

The testicular dysgenesis syndrome (TDS) hypothesis, which proposes that common reproductive disorders of newborn and adult human males may have a common fetal origin, is largely untested. We tested this hypothesis using a rat model involving gestational exposure to dibutyl phthalate (DBP), which suppresses testosterone production by the fetal testis. We evaluated if induction of TDS via testosterone suppression is restricted to the "masculinization programming window" (MPW), as indicated by reduction in anogenital distance (AGD).

An Infrared Absorbance Sensor for the Detection of Melanoma in Skin Biopsies.

An infrared (IR) absorbance sensor has been designed, realized and tested with the aim of detecting malignant melanomas in human skin biopsies. The sensor has been designed to obtain fast measurements (80 s) of a biopsy using a small light spot (0.5 mm in diameter, typically five to 10 times smaller than the biopsy size) to investigate different biopsy areas.

An Impedance-Based Mold Sensor with on-Chip Optical Reference.

A new miniaturized sensor system with an internal optical reference for the detection of mold growth is presented. The sensor chip comprises a reaction chamber provided with a culture medium that promotes the growth of mold species from mold spores. The mold detection is performed by measuring impedance changes with integrated electrodes fabricated inside the reaction chamber.

Analgesic exposure in pregnant rats affects fetal germ cell development with inter-generational reproductive consequences.

Analgesics which affect prostaglandin (PG) pathways are used by most pregnant women. As germ cells (GC) undergo developmental and epigenetic changes in fetal life and are PG targets, we investigated if exposure of pregnant rats to analgesics (indomethacin or acetaminophen) affected GC development and reproductive function in resulting offspring (F1) or in the F2 generation. Exposure to either analgesic reduced F1 fetal GC number in both sexes and altered the tempo of fetal GC development sex-dependently, with delayed meiotic entry in oogonia but accelerated GC differentiation in males.

Prolonged exposure to acetaminophen reduces testosterone production by the human fetal testis in a xenograft model.

Most common male reproductive disorders are linked to lower testosterone exposure in fetal life, although the factors responsible for suppressing fetal testosterone remain largely unknown. Protracted use of acetaminophen during pregnancy is associated with increased risk of cryptorchidism in sons, but effects on fetal testosterone production have not been demonstrated. We used a validated xenograft model to expose human fetal testes to clinically relevant doses and regimens of acetaminophen.

Hydrogel-based microfluidic incubator for microorganism cultivation and analyses.

This work presents an array of microfluidic chambers for on-chip culturing of microorganisms in static and continuous shear-free operation modes. The unique design comprises an in-situ polymerized hydrogel that forms gas and reagent permeable culture wells in a glass chip. Utilizing a hydrophilic substrate increases usability by autonomous capillary priming.

Comparative effects of di(n-butyl) phthalate exposure on fetal germ cell development in the rat and in human fetal testis xenografts.

Background: Phthalate exposure induces germ cell effects in the fetal rat testis. Although experimental models have shown that the human fetal testis is insensitive to the steroidogenic effects of phthalates, the effects on germ cells have been less explored.

Objectives: We sought to identify the effects of phthalate exposure on human fetal germ cells in a dynamic model and to establish whether the rat is an appropriate model for investigating such effects.

Dynamic changes in DNA modification states during late gestation male germ line development in the rat.

Background: Epigenetic reprogramming of fetal germ cells involves the genome-wide erasure and subsequent re-establishment of DNA methylation. Mouse studies indicate that DNA demethylation may be initiated at embryonic day (e) 8 and completed between e11.5 and e12.

Fetal programming of adult Leydig cell function by androgenic effects on stem/progenitor cells.

Fetal growth plays a role in programming of adult cardiometabolic disorders, which in men, are associated with lowered testosterone levels. Fetal growth and fetal androgen exposure can also predetermine testosterone levels in men, although how is unknown, because the adult Leydig cells (ALCs) that produce testosterone do not differentiate until puberty. To explain this conundrum, we hypothesized that stem cells for ALCs must be present in the fetal testis and might be susceptible to programming by fetal androgen exposure during masculinization.

Regulation of the germ stem cell niche as the foundation for adult spermatogenesis: a role for miRNAs?

Within the testis the spermatogonial stem cells reside in a unique microenvironment, or 'niche', which includes the surrounding somatic cells. The regulation of the balance between self-renewal and differentiation of spermatogonial stem cells determines the lifelong supply of spermatozoa by maintaining a population of undifferentiated spermatogonial stem cells and ensuring that adequate numbers of spermatogonia undergo spermatogenesis. Mouse models have been instrumental in determining a large number of factors involved in regulating the spermatogonial stem cell self-renewal and/or differentiation.

ENDOGLIN is dispensable for vasculogenesis, but required for vascular endothelial growth factor-induced angiogenesis.

ENDOGLIN (ENG) is a co-receptor for transforming growth factor-β (TGF-β) family members that is highly expressed in endothelial cells and has a critical function in the development of the vascular system. Mutations in Eng are associated with the vascular disease known as hereditary hemorrhagic telangiectasia type l. Using mouse embryonic stem cells we observed that angiogenic factors, including vascular endothelial growth factor (VEGF), induce vasculogenesis in embryoid bodies even when Eng deficient cells or cells depleted of Eng using shRNA are used.

Epigenetic reprogramming: preparing the epigenome for the next generation.

Epigenetic reprogramming of germ cells involves the genome-wide erasure and subsequent re-establishment of DNA methylation, along with reprogramming of histone modification profiles and the eventual incorporation of histone variants. These linked processes appear to be key for the establishment of the correct epigenetic regulation of this cell lineage. Mouse studies indicate that DNA demethylation may be initiated at E (embryonic day) 8 with rapid and substantial erasure occurring between E11.

Diethylstilboestrol exposure does not reduce testosterone production in human fetal testis xenografts.

In rodents, in utero exposure to exogenous estrogens including diethylstilboestrol (DES) results in major suppression of steroidogenesis in fetal testes. Whether similar effects occur in the human fetal testis is equivocal. Based on the results of the rodent studies, we hypothesised that exposure of human fetal testes to DES would result in a reduction in testosterone production.

Studying enzymatic bioreactions in a millisecond microfluidic flow mixer.

In this study, the pre-steady state development of enzymatic bioreactions using a microfluidic mixer is presented. To follow such reactions fast mixing of reagents (enzyme and substrate) is crucial. By using a highly efficient passive micromixer based on multilaminar flow, mixing times in the low millisecond range are reached.