Engineering In Situ Weldable Vascular Devices.

(1) Background: The minimally invasive implantation of medical devices is largely limited by their insertion profile, and, therefore, minimizing them constitutes a leading trend in the field. (2) Methods: This study introduces the in situ welding strategy, whereby the components of the stent grafts used to treat abdominal aortic aneurysms were decoupled, deployed sequentially, and welded together at the aneurysmal site, greatly reducing their insertion profile. Polyurethane elastomers were used to produce the graft and to coat the metallic struts of the stent to render it in vivo weldable. Results: The composition of the polyurethanes was fine-tuned, so to minimize the insertion profiles and optimize the welding properties and the clinical performance of the devices assembled. The stent and graft were deployed successively in pigs via a small 8F introducer, in situ welded, and the patency of the bi-component device was confirmed over a three-month post-implantation period. The strength of the stent/graft welded connection was fully retained, with no de-welding observed. Conclusions: The in situ welding strategy resulted in implantations that were easier to perform and markedly less injurious to tissues and organs, largely expanding the applicability of these ultra-minimally invasive procedures to especially frail segments of the population.

4D Printing of Shape Memory-Based Personalized Endoluminal Medical Devices.

The convergence of additive manufacturing and shape-morphing materials is promising for the advancement of personalized medical devices. The capability to transform 3D objects from one shape to another, right off the print bed, is known as 4D printing. Shape memory thermosets can be tailored to have a range of thermomechanical properties favorable to medical devices, but processing them is a challenge because they are insoluble and do not flow at any temperature. This study presents here a strategy to capitalize on a series of medical imaging modalities to construct a printable shape memory endoluminal device, exemplified by a tracheal stent. A methacrylated polycaprolactone precursor with a molecular weight of 10 000 g mol-1 is printed with a UV-LED stereolithography printer based on anatomical data. This approach converges with the zeitgeist of personalized medicine and it is anticipated that it will broadly expand the application of shape memory-exhibiting biomedical devices to myriad clinical indications.

3D Printing: 3D Printing of Shape Memory Polymers for Flexible Electronic Devices (Adv. Mater. 22/2016).

On page 4449, D. Cohn, S. Magdassi, and co-workers describe a general and facile method based on 3D printing of methacrylated macromonomers to fabricate shape-memory objects that can be used in flexible and responsive electrical circuits. Such responsive objects can be used in the fabrication of soft robotics, minimal invasive medical devices, sensors, and wearable electronics. The use of 3D printing overcomes the poor processing characteristics of thermosets and enables complex geometries that are not easily accessible by other techniques.

3D Printing of Shape Memory Polymers for Flexible Electronic Devices.

The formation of 3D objects composed of shape memory polymers for flexible electronics is described. Layer-by-layer photopolymerization of methacrylated semicrystalline molten macromonomers by a 3D digital light processing printer enables rapid fabrication of complex objects and imparts shape memory functionality for electrical circuits.

Discovery of a trans-dichloroethene-respiring Dehalogenimonas species in the 1,1,2,2-tetrachloroethane-dechlorinating WBC-2 consortium.

The WBC-2 consortium is an organohalide-respiring anaerobic microbial enrichment culture capable of dechlorinating 1,1,2,2-tetrachloroethane (TeCA) to ethene. In the WBC-2 culture, TeCA is first transformed to trans-dichloroethene (tDCE) by dichloroelimination; tDCE is subsequently transformed to vinyl chloride (VC) and then to ethene by hydrogenolysis. Analysis of 16S rRNA gene clone libraries from culture DNA revealed sequences from three putative dechlorinating organisms belonging to Dehalococcoides, Dehalobacter, and Dehalogenimonas genera. Quantitative PCR primers were designed for each of these sequences, and their abundance was quantified in enrichment cultures over time. These data revealed that complete dechlorination of TeCA to ethene involves all three organisms. Dehalobacter spp. grew during the dihaloelimination of TeCA to tDCE, while Dehalococcoides and Dehalogenimonas spp. grew during hydrogenolysis of tDCE to ethene. This is the first time a genus other than Dehalococcoides has been implicated in dechlorination of tDCE to VC.