Microneedle (MN), a miniaturized needle with a length‐scale of hundreds of micrometers, has received a great deal of attention because of its minimally invasive, pain‐free, and easy‐to‐use nature. However, a major challenge for controlled long‐term drug delivery or biosensing using MN is its low tissue adhesion. Although microscopic structures with high tissue adhesion are found from living creatures in nature (e.g., microhooks of parasites, barbed stingers of honeybees, quills of porcupines), creating MNs with such complex microscopic features is still challenging with traditional fabrication methods. Here, a MN with bioinspired backward‐facing curved barbs for enhanced tissue adhesion, manufactured by a digital light processing 3D printing technique, is presented. Backward‐facing barbs on a MN are created by desolvation‐induced deformation utilizing cross‐linking density gradient in a photocurable polymer. Barb thickness and bending curvature are controlled by printing parameters and material composition. It is demonstrated that tissue adhesion of a backward‐facing barbed MN is 18 times stronger than that of barbless MN. Also demonstrated is sustained drug release with barbed MNs in tissue. Improved tissue adhesion of the bioinspired MN allows for more stable and robust performance for drug delivery, biofluid collection, and biosensing.
We present a novel framework for the fluid dynamics analysis of healthy subjects and patients affected by ascending thoracic aorta aneurysm (aTAA). Our aim is to obtain indications about the effect of a bulge on the hemodynamic environment at different enlargements. 3D surface models defined from healthy subjects and patients with aTAA, selected for surgical repair, were generated. A representative shape model for both healthy and pathological groups has been identified. A morphing technique based on radial basis functions (RBF) was applied to mould the shape relative to healthy patient into the representative shape of aTAA dataset to enable the parametric simulation of the aTAA formation. CFD simulations were performed by means of a finite volume solver using the mean boundary conditions obtained from three-dimensional (PC-MRI) acquisition. Blood flow helicity and flow descriptors were assessed for all the investigated models. The feasibility of the proposed integrated approach of RBF morphing technique and CFD simulation for aTAA was demonstrated. Significant hemodynamic changes appear at the 60% of the bulge progression. An impingement of the flow toward the bulge was observed by analyzing the normalized flow eccentricity index.
Background:
3D printing represents an emerging technology in the field of cardiovascular medicine. 3D
printing can help to perform a better analysis of complex anatomies to optimize intervention planning.
Methods:
A systematic review was performed to illustrate the 3D printing technology and to describe the workflow to
obtain 3D printed models from patient-specific images. Examples from our laboratory of the benefit of 3D printing in
planning interventions were also reported.
Results:
3D printing technique is reliable when applied to high-quality 3D image data (CTA, CMR, 3D echography) but it
still need the involvement of expert operators for image segmentation and mesh refinement. 3D printed models could be
useful in interventional planning, although prospective studies with comprehensive and clinically meaningful endpoints
are required to demonstrate the clinical utility.
Conclusion:
3D printing can be used to improve anatomy understanding and surgical planning.
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