Fully 3D printed fluidic devices with integrated valves and pumps for flow injection analysis.

The use of a PolyJet 3D printer to create a microfluidic device that has integrated valves and pumps is described. The process uses liquid support and stacked printing to result in fully printed devices that are ready to use within minutes of fabrication after minimal post-processing. A unique feature of PolyJet printing is the ability to incorporate several different materials of varying properties into one print. In this work, two commercially available materials were used: a rigid-transparent plastic material (VeroClear) was used to define the channel regions and the bulk of the device, while the pumps/valves were printed in a flexible, rubber-like material (Agilus30). The entire process, from initial design to testing takes less than 4 hours to complete. The performance of the valves and pumps were characterized by fluorescence microscopy. A flow injection analysis device that enabled the discrete injections of analyte plugs was created, with on-chip pumps being used to move the fluid streams. The injection process was found to be reproducible and linearly correlated with changes in analyte concentration. The utility was demonstrated with the injection and rapid lysis of fluorescently-labeled endothelial cells. The ability to produce a device with integrated pumps/valves in one process significantly adds to the applicability of 3D printing to create microfluidic devices for analytical measurements.

Risk factors for development of melanoma brain metastasis and disease progression: a single-center retrospective analysis.

Melanoma metastasis to the brain is associated with a poor prognosis. We sought to determine patient demographics and primary tumor factors associated with the development of brain metastasis (BM) and survival. We also investigated whether the BM detection setting (routine screening vs. symptomatic presentation) affected clinical outcomes. A database of melanoma patients seen from 1999 to 2015 at our institution was reviewed to identify patients who developed BM. Patients with BM were matched by initial stage with patients who did not develop BM as a control group. Patient demographics, primary tumor characteristics, and clinical outcomes were analyzed. A total of 123 patients with BM were matched by initial presenting stage to 237 patients without BM. The characteristics of the primary melanoma tumor associated with BM development included location on the scalp (P=0.030), nodular histologic type (P=0.020), and Breslow depth more than 4 mm (P=0.048), whereas location on the leg was associated with decreased BM risk (P=0.006). In patients with BM, time to first recurrence for melanomas of the scalp was significantly shorter (10.8 vs. 24.8 months, P=0.007) than nonscalp head and neck tumors. Patient stage, tumor depth, nodular type, and ulceration were also associated with worse clinical outcomes. There were no differences in the clinical outcomes between patients whose BM were detected upon routine screening versus those detected upon symptomatic presentation. In summary, factors predictive of development of BM included primary scalp location, nodular type, and depth. In BM patients, scalp location, stage, tumor depth, nodular type, and ulceration, but not detection setting, were associated with worse clinical outcomes.

Elective laparoscopic fetal laser photocoagulation in twin-twin transfusion syndrome: a case report.

Twin-twin transfusion syndrome (TTTS) is a complication of multiple gestation in which arteriovenous vascular communications occur in a shared placenta. Due to these communications, there is an imbalance of blood flow between the developing fetuses. This results in 1 twin becoming the donor and the other becoming the recipient. In severe cases, the recipient may experience polycythemia, polyhydramnios, and hydrops fetalis, while in the donor oligohydramnios and severe anemia may develop. It has been reported that fetal mortality can reach as high as 60% to 80% if TTTS develops before 26 weeks' gestation and goes untreated. Therapeutic options available include decompression amniocentesis, amniotic septostomy, interruption of the placental vessel communications, and selective fetal reduction. Selective fetoscopic laser photocoagulation of abnormal vascular communications has shown to result in increasing survival rates and has become a definitive treatment option for severe TTTS. The case report presented involves a 32-year-old, gravida 5, para 2 patient at 19 weeks' estimated gestational age with a monochorionic diamniotic twin gestation with TTS diagnosed using ultrasonography presenting for an elective laparoscopic fetal laser photocoagulation.