The most common three-dimensional (3D) printing method is material extrusion, where a pre-made filament is deposited layer-by-layer. In recent years, low-cost polycaprolactone (PCL) material has increasingly been used in 3D printing, exhibiting a sufficiently high quality for consideration in cranio-maxillofacial reconstructions. To increase osteoconductivity, prefabricated filaments for bone repair based on PCL can be supplemented with hydroxyapatite (HA). However, few reports on PCL/HA composite filaments for material extrusion applications have been documented. In this study, solvent-free fabrication for PCL/HA composite filaments (HA 0%, 5%, 10%, 15%, 20%, and 25% weight/weight PCL) was addressed, and parameters for scaffold fabrication in a desktop 3D printer were confirmed. Filaments and scaffold fabrication temperatures rose with increased HA content. The pore size and porosity of the six groups’ scaffolds were similar to each other, and all had highly interconnected structures. Six groups’ scaffolds were evaluated by measuring the compressive strength, elastic modulus, water contact angle, and morphology. A higher amount of HA increased surface roughness and hydrophilicity compared to PCL scaffolds. The increase in HA content improved the compressive strength and elastic modulus. The obtained data provide the basis for the biological evaluation and future clinical applications of PCL/HA material.

The limitations of traditional, autologous bone grafts, such as the scarcity of donor material and the risks of secondary surgical trauma, have spurred the development of alternatives for the repair of large bone defects. Bionic bone scaffolds fabricated via fused deposition modeling (FDM)—a three-dimensional (3D) printing technique—are considered promising. While gyroid-structured scaffolds mimic the complex micro-architecture of cancellous bone, their application in FDM 3D printing remains understudied. Furthermore, no consensus has been reached on the ideal pore size for gyroid scaffolds, which is influenced by the infill density. In this study, we fabricated five groups of polycaprolactone/hydroxyapatite (PCL/HA) scaffolds with different infill densities (40%, 45%, 50%, 55%, and 60%) using a solvent-free filament preparation method. Scanning electron microscopy (SEM) observation showed that all scaffolds exhibit an interconnected porous structure. The scaffold with the 55% infill density, featuring a pore size of 465 ± 63 μm, demonstrated optimal hydrophilicity and mechanical properties comparable to natural cancellous bone. In addition, this scaffold supported cellular bridging within its pores and showed the highest alkaline phosphatase (ALP) activity and calcium salt deposition. Our findings offer novel insights into the design of gyroid-like scaffolds and their fabrication via FDM, paving the way for potential clinical applications.

Background: Bladder cancer is often prone to recurrence and metastasis. We sought to construct nomogram models to predict the overall survival (OS) and cancer-specific survival (CSS) of bladder cancer patients. Methods: A reliable random split-sample approach was used to divide patients into two groups: modeling and validation cohorts. Uni-variate and multivariate survival analyses were used to obtain the independent prognostic risk factors based on the modeling cohort. A nomogram was constructed using the R package, “rms”. Harrell’s concordance index (C-index), calibration curves and receiver operating characteristic (ROC) curves were applied to evaluate the discrimination, sensitivity and specificity of the nomograms using the R packages “hmisc”, “rms” and “timeROC”. A decision curve analysis (DCA) was used to evaluate the clinical value of the nomograms via R package “stdca.R”. Results: 10,478 and 10,379 patients were assigned into nomogram modeling and validation cohorts, respectively (split ratio ≈ 1:1). For OS and CSS, the C-index values for internal validation were 0.738 and 0.780, respectively, and the C-index values for external validation were 0.739 and 0.784, respectively. The area under the ROC curve (AUC) values for 5- and 8-year OS and CSS were all greater than 0.7. The calibration curves show that the predicted probability values of 5- and 8-year OS and CSS are close to the actual OS and CSS. The decision curve analysis revealed that the two nomograms have a positive clinical benefit. Conclusion: We successfully constructed two nomograms to forecast OS and CSS for bladder cancer patients. This information can help clinicians conduct prognostic evaluations in an individualized manner and tailor personalized treatment plans.