Successful anterior cruciate ligament (ACL) reconstructions strive for a firm bone-ligament integration. With the aim to establish an enthesis-like construct, embroidered functionalized scaffolds were colonized with spheroids of osteogenically differentiated human mesenchymal stem cells (hMSCs) and lapine (l) ACL fibroblasts in this study. These triphasic poly(L-lactide-co-ε-caprolactone) and polylactic acid (P(LA-CL)/PLA) scaffolds with a bone-, a fibrocartilage transition- and a ligament zone were colonized with spheroids directly after assembly (DC) or with 14-day pre-cultured lACL fibroblast and 14-day osteogenically differentiated hMSCs spheroids (=longer pre-cultivation, LC). The scaffolds with co-cultures were cultured for 14 days. Cell vitality, DNA and sulfated glycosaminoglycan (sGAG) contents were determined. The relative gene expressions of collagen types I and X, Mohawk, Tenascin C and runt-related protein (RUNX) 2 were analyzed. Compared to the lACL spheroids, those with hMSCs adhered more rapidly. Vimentin and collagen type I immunoreactivity were mainly detected in the hMSCs colonizing the bone zone. The DNA content was higher in the DC than in LC whereas the sGAG content was higher in LC. The gene expression of ECM components and transcription factors depended on cell type and pre-culturing condition. Zonal colonization of triphasic scaffolds using spheroids is possible, offering a novel approach for enthesis tissue engineering.

The interest in bio‐based alternatives to classical polyesters such as poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) is steadily growing to achieve a more sustainable approach to polymer materials. In this study, PBT/poly(butylene furanoate) (PBF) blends are prepared, characterized and extrusion foamed. PBF as a bio‐based polyester offers two advantages. The ecological footprint of the material is reduced, and additionally, it can be used in Diels‐Alder reactions at the blend surface to support fusion of the foamed beads. The blending behavior of the polyesters is investigated using samples prepared in a microcompounder, particularly focused on the miscibility of the blends and transesterification reactions. The blends are thermodynamically immiscible but show a certain degree of transesterification according to nuclear magnetic resonance (NMR) spectroscopy. The morphology of blend beads produced by an extrusion foaming process is analyzed regarding their cell density, cell size distribution, and open‐cell content. It is shown that PBF has a positive effect on the bead foam morphology. The use of a bifunctional linker designed for chemical fusion of the bead surfaces allows to obtaining of molded parts, in contrast to beads containing pure PBT.

Stenting is a widely used treatment procedure for coronary artery disease around the world. Stents have a complex geometry, which makes the characterization of their corrosion difficult due to the absence of a mathematical model to calculate the entire stent surface area (ESSA). Therefore, corrosion experiments with stents are mostly based on qualitative analysis. Additionally, the quantitative analysis of corrosion is conducted with simpler samples made of stent material instead of stents, in most cases. At present, several methods are available to calculate the stent outer surface area (SOSA), whereas no model exists for the calculation of the ESSA. This paper presents a novel mathematical model for the calculation of the ESSA using the SOSA as one of the main parameters. The ESSA of seven magnesium alloy stents (MeKo Laser Material Processing GmbH, Sarstedt, Germany) were calculated using the developed model. The calculated SOSA and ESSA for all stents are 33.34%(±0.26%) and 111.86 mm (±0.85 mm), respectively. The model is validated by micro-computed tomography (micro-CT), with a difference of 12.34% (±0.46%). The value of corrosion rates calculated using the ESSA computed with the developed model will be 12.34% (±0.46%) less than that of using ESSA obtained by micro-CT.

The success of 3D printing based on vat polymerization by spatially controlled UV light exposure strongly depends on appropriate resins. However, in search of new resins, optimizing a resin's composition as well as its printing parameters can be time‐consuming and labor‐intensive. To address these challenges, we present a rapid parameter screening that enables efficient evaluation of 24 printing parameter settings within one print focusing on exposure energy, exposure time, and layer thickness as the most crucial process parameters in 3D printing based on digital light processing (DLP). Our step test minimizes the required number of experimental iterations and 3D prints by relying on optical characterization without the need for special analytical devices, making it rapid and accessible for a broad range of users across different disciplines. For a proof of concept, the step test is applied to define optimal printing parameters of three commercial resins and evaluate the polymerization efficiency of two predominantly biobased, noncommercial resins containing either phenylbis(2,4,6‐trimethylbenzoyl)phosphine oxide or curcumin as photoinitiators. With that, we introduce a straightforward test that is easy to implement and adaptable to other UV polymerization‐based printing methods, speeding up the time from resin screening to optimal printing parameters and products.

Anterior cruciate ligament (ACL) rupture causes joint instability and increases the risk of osteoarthritis due to the ligament’s limited healing capacity. Silk, particularly from Bombyx mori, combines high cytocompatibility with robust biomechanical properties. Its main components are fibroin and sericin, with the latter usually being removed to reduce immunogenicity and improve biocompatibility. Silk threads were processed either as raw silk (designated as “untreated”) or subjected to a patented degumming procedure (DE102021118652A1) to obtain purified silk. Both variants were used alone or in combination with poly(L-lactic acid-co-caprolactone) (P(LA-CL)) fibers, yielding four scaffold groups: untreated silk, purified silk, untreated silk/P(LA-CL), and purified silk/P(LA-CL). Three-layer scaffolds were fabricated using a zigzag embroidery pattern. Structural analysis revealed scaffold porosity of ≈38% for silk, ≈46% for purified silk, and up to ≈70% for scaffolds containing P(LA-CL). Uniaxial tensile testing showed that purified silk scaffolds achieved the highest maximum force at break (≈684 N), whereas elongation at maximum force was limited in the hybrid scaffolds—silk/P(LA-CL) ≈ 28% and p-silk/P(LA-CL) ≈ 32%—despite the high intrinsic extensibility of P(LA-CL). All scaffolds supported cell adhesion and showed no cytotoxicity. P-silk and p-silk/P(LA-CL) scaffolds exhibited the highest fibroblast adherence and pronounced paxillin expression, indicating strong cell–material interactions. Gene expression of ligament-related ECM components and connexin 43 was maintained across all groups. These results demonstrate that embroidered silk fibroin scaffolds provide a reproducible architecture with tunable porosity and mechanical properties, supporting fibroblast colonization and ligament-specific ECM expression. Such scaffolds represent promising candidates for ACL tissue engineering and future graft development.