A major challenge to the clinical translation of tissue‐engineered ear scaffolds for ear reconstruction is the limited auricular chondrocyte (hAuC) yield available from patients. Starting with a relatively small number of chondrocytes in culture results in dedifferentiation and loss of phenotype with subsequent expansion. To significantly decrease the number of chondrocytes required for human elastic cartilage engineering, we co‐cultured human mesenchymal stem cells (hMSCs) with HAuCs to promote healthy elastic cartilage formation. HAuCs along with human bone marrow‐derived hMSCs were encapsulated into 1% Type I collagen at 25 million/mL total cell density with different ratios (HAuCs/hMSCs: 10/90, 25/75, 50/50) and then injected into customized 3D‐printed polylactic acid (PLA) ridged external scaffolds, which simulate the shape of the auricular helical rim, and implanted subcutaneously in nude rats for 1, 3 and 6 months. The explanted constructs demonstrated near complete volume preservation and topography maintenance of the ridged “helical” feature after 6 months with all ratios. Cartilaginous appearing tissue formed within scaffolds by 3 months, verified by histologic analysis demonstrating mature elastic cartilage within the constructs with chondrocytes seen in lacunae within a Type II collagen and proteoglycan‐enriched matrix, and surrounded by a neoperichondrial external layer. Compressive mechanical properties comparable to human elastic cartilage were achieved after 6 months. Co‐implantation of hAuCs and hMSCs in collagen within an external scaffold efficiently produced shaped human elastic cartilage without volume loss even when hAuC comprised only 10% of the implanted cell population, marking a crucial step toward the clinical translation of auricular tissue engineering.

Background Because of the association of textured breast implants with breast implant–associated anaplastic large cell lymphoma, anatomically shaped breast implants, which rely on a textured surface to maintain rotational stability, have been recalled from the market. The dearth of anatomically shaped implants on the market reflects a need for novel breast implant technology, which has been traditionally developed by commercial breast implant manufacturers due to the complexities of implant manufacturing. To increase the accessibility of preclinical breast implant research, miniature breast implants made from polydimethylsiloxane were designed and fabricated for high throughput and low-cost prototyping and in vivo testing of both smooth and textured implants in a laboratory setting. Methods Two-piece negative molds measuring 2 × 1 cm were constructed in Fusion360 and 3D printed in Polysmooth filament. Textured molds were painted with a mixture of an epoxy and fine sugar or granular salt to create textured surfaces, while molds for smooth implants were smoothed using ethanol spray. Molds were injected with polydimethylsiloxane and cured for 12 hours at 37°C. The surface topography of laboratory-made implants and commercial textured and smooth implant shells was analyzed using scanning electron microscopy and implants were evaluated in vivo in an immunocompetent rodent model. Results Implants retained the original dome shape of the 3D-printed molds. Qualitative assessment of scanning electron microscopy images demonstrated similar surface topography between laboratory-made and commercial smooth and textured implants. There was no statistical difference in the diameter or density of the surface indentations of the Allergan's textured implant compared with laboratory-made textured implants (P > 0.05). Finally, the surface topography and thickness of laboratory-made implant capsules were similar to previously published data using industry made miniature silicone devices implanted in rats. Conclusions This study demonstrates a low-cost, highly customizable approach to fabricate miniature smooth and textured breast implant prototypes for in vivo studies. The accessibility of this implant fabrication strategy allows nonindustry investigators to develop novel implant designs more rapidly for preclinical investigation.

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