A microfluidic device for digital manipulation of gaseous samples.

Digital microfluidics is known for fine manipulation of sub-millimeter samples, with applications from biological sample preparation to diagnostic testing. Unfortunately, until now, it has been only limited to liquid phases. In this paper, we present a new system based on a digital microfluidic platform (DMFP), which is able to digitally manipulate gaseous samples, such as alkanes from n-hexane to n-nonane. The DMFP relies mostly on interconnected micropreconcentrators (µPCs) to trap and release the samples depending on their controlled temperature. We show that the DMFP is capable of performing all basic operations of digital microfluidics: trapping/releasing and moving samples, adding samples and separating samples. As a first example of a more complex programmable use of our DMFP, we measured the breakthrough volume of alkanes on a Tenax TA adsorbent. The results were consistent with tabulated values obtained with standard laboratory instruments. This DMFP promises great possibilities for more complex programmable gas microfluidics digital devices and the development of new digital gas sample preparation and analysis methods.

Coil-Induced Perforation of Recently Ruptured Cerebral Aneurysm during Embolization. Causes and Avoidance.

SUMMARY: Most coil-induced aneurysmal ruptures during endovascular treatment occur in small, recently ruptured aneurysms, and after placement of at least one coil. In cases where the distal part of the microcatheter cannot move back due to its straightness and tightness, the last coil deployed may advance towards the aneurysmal wall through intercircles of deposited coils. To solve this problem, after complete occlusion of the sac is obtained, the microcatheter is slightly withdrawn until the tip of the catheter is placed in the neck, and then the neck is occluded with the appropriate coil.