A Personalized Multifunctional 3D Printed Shape Memory‐Displaying, Drug Releasing Tracheal Stent

Abstract

The ability to engineer custom-made medical devices and to implant them minimally invasively are two important trends in modern surgery. The personalization of the device is achieved by 3D printing it, while the capacity to deploy it minimally invasively harnesses the shape memory behavior displayed by the inks used. This study introduces a 3D printed, shape memorydisplaying tracheal stent based on novel, flexible photo-polymerizable inks comprising polypropylene glycol/polycaprolactone triblocks. This research introduces the in situ welding strategy, whereby thin and flexible layers of the stent are separately printed, sequentially deployed, and then welded together at the tracheal site. By doing so, the insertion profile of the device is dramatically reduced and its flexibility largely increased. Porous stents are 3D printed seeking to prevent mucus plugging. By combining more than one ink, their properties are further fine-tuned. Polyethylene glycol chains are covalently bonded to the stent surface to minimize biofilm formation, an important drawback of current tracheal stents. The in vitro cell viability and cell adhesion behavior of the treated surfaces reveal their compatibility and anti-adhesive behavior. In order to prevent implant-related infections, ciprofloxacin is added to the ink, and released in vitro over time, rendering the stent with antibacterial activity.

Challenges and Opportunities in 3D Printing of Biodegradable Medical Devices by Emerging Photopolymerization Techniques

“…Highest MW photopolymers tested PPF (31 000 g mol -1 ) with 50 wt% DEF [67] Poly(CL-co-DLLA)-MA (15 000 g mol -1 ) with 8 wt% NVP [68] NA NA Estimated value in theory and from the literature (refs. [68][69][70][71][72][73][74]); b) Obtained from the information sheet of xolo GmbH; c) Average 20-35 mm h -1 for commercial DLP printers obtained from gorillaoutput.com; d) Currently only for small objects in the centimeter range; NA: not available.…”

“…[ 70 ] Most recently, they further improved the 3D printing materials by developing poly(propylene glycol)/PCL triblock photopolymers with MW ranging from 9700 to 13 700 g mol –1 . [ 71 ] The 3D printed tracheal stents exhibited largely increased flexibility due to the introduction of poly(propylene glycol) segments (typical MW of 8000 g mol –1 ), while maintaining excellent shape‐memory properties (Figure 3b).…”

“…Reproduced with permission. [ 71 ] Copyright 2021, Wiley‐VCH. c) 3D printed gyroid scaffolds, ear model, and vascular model from copolymers of D,L‐LA and CL with varied MW, and cell staining after they were seeded on the 3D printed films at day 1.…”

Recent Trends in Advanced Photoinitiators for Vat Photopolymerization 3D Printing

“…[1][2][3] As a chemical process-based 3D printing technique, vat photopolymerization possesses remarkable advantages, such as flexible material design, high print resolution, fast printing, and smooth print surface. [4][5][6] As most commonly used vat photopolymerization methods, stereolithography (SLA), [7,8] digital light processing (DLP), [9,10] and continuous liquid interface production (CLIP) [11,12] have shown wide DOI: 10.1002/marc.202200202 potential in customized fabrication of tissue scaffolds, [13,14] medical devices, [15,16] soft robots, [17,18] dental implants, [19,20] microfluidic devices [21,22] and drug delivery systems. [6,23] SLA and DLP usually rely on the layer-bylayer solidification of a liquid resin containing (macro)monomers that can be photocrosslinked under light irradiation in the presence of a photoinitiator.…”

4D-printed bilayer hydrogel with adjustable bending degree for enteroatmospheric fistula closure

“…Therefore, 4D printing of implants that conform to biological curvature can be a potential technology for reconstitution of defective organs and tissues. Various 4D printing strategies have been applied for the manufacture of surgical implants on recent trends, such as bone scaffolds [ 30 , 31 ], tracheal stents [ 28 , 32 ], and cardiac patches [ 29 ]. Their deformation mainly depends on two types of materials: (i) shape memory polymers (SMPs), such as thermo-sensitive polycaprolactone-based composites [ 32 ]; (ii) responsive shape morphing materials, such as 3D structures deformed by anisotropic swelling property distributed spatially [ 28 ].…”