Rapid Prototyping of Organ-on-a-Chip Devices Using Maskless Photolithography.

Organ-on-a-chip (OoC) and microfluidic devices are conventionally produced using microfabrication procedures that require cleanrooms, silicon wafers, and photomasks. The prototyping stage often requires multiple iterations of design steps. A simplified prototyping process could therefore offer major advantages. Here, we describe a rapid and cleanroom-free microfabrication method using maskless photolithography. The approach utilizes a commercial digital micromirror device (DMD)-based setup using 375 nm UV light for backside exposure of an epoxy-based negative photoresist (SU-8) on glass coverslips. We show that microstructures of various geometries and dimensions, microgrooves, and microchannels of different heights can be fabricated. New SU-8 molds and soft lithography-based polydimethylsiloxane (PDMS) chips can thus be produced within hours. We further show that backside UV exposure and grayscale photolithography allow structures of different heights or structures with height gradients to be developed using a single-step fabrication process. Using this approach: (1) digital photomasks can be designed, projected, and quickly adjusted if needed; and (2) SU-8 molds can be fabricated without cleanroom availability, which in turn (3) reduces microfabrication time and costs and (4) expedites prototyping of new OoC devices.

Angiographic findings and outcomes after embolization of patients with suspected postabortion uterine arteriovenous fistula.

INTRODUCTION: The purpose of this study is to assess the angiographic incidence of uterine arteriovenous fistula (UAVF) in women referred for a high ultrasonographic suspicion in a postabortion setting and to evaluate the safety, efficacy and impact on further fertility of uterine artery embolization (UAE) in this indication. MATERIALS AND METHODS: A monocentric retrospective study of 31patients managed by uterine artery embolization for suspected UAVF after spontaneous or induced first trimester abortion. The diagnosis of UAVF was confirmed when an early venous drainage was identified on the angiogram. Technical success was defined as complete exclusion of the vascular lesion. Clinical success was defined as the absence of bleeding during the clinical follow-up and during the surgery in case of hysteroscopic resection. Information about further fertility was gathered by phone calls to the patients. RESULTS: The mean age of the patients was 30.8 (±6.0) years. The diagnosis of UAVF was angiographically confirmed in 6 patients (19.4 %). Angiographic findings of retained product of conception (RPOC) with varying degrees of vascularity were observed in remaining patients. The technical success rate of UAE was 100 %, mostly through a proximal and bilateral embolization using a resorbable agent (27/31 patients, 87.1 %). The clinical success rate of UAE was 100 % in the group treated by a single UAE. We did not notice any bleeding during the surgery in the group of patients who needed a further hysteroscopic resection. 14 patients led at least one subsequent pregnancy to term without any difficulty. CONCLUSION: UAVF is a rare condition. We supposed it may constitute the ultimate stage in the natural history of the retained products of conception with "marked vascularity". UAE seems to be an effective and safe first-line treatment.