Cell-only bioprinting of articular cartilage progenitor cells within a physically constraining support bath to engineer structurally organized grafts
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Engineering functional articular cartilage (AC) grafts is one of the greatest challenges in tissue engineering. Recapitulating the arcade-like collagen organisation of AC, which is integral to the tissues’ strength and stiffness, is necessary to engineer truly functional grafts. This motivates the need for innovative strategies to control collagen alignment in engineered tissues in a programmable manner. Emerging 3D bioprinting strategies can provide spatially defined cues to guide tissue growth. Therefore, the goal of this study was to use embedded bioprinting to provide spatially defined boundary conditions to AC progenitor cells (ACP) to direct collagen organization and support the development of biomimetic cartilage tissues. ACPs were isolated through differential adhesion to fibronectin and demonstrated superior chondrogenesis to donor matched chondrocytes. Two different approaches (casting and 3D bioprinting) were used to physically constrain ACPs with external boundaries of differing widths (250, 500, or 750 μm). For both approaches, thinner boundaries promoted greater collagen alignment along the long axis of the developing tissue. Building on this, ACPs were bioprinted into a sheet, with collagen fibers aligning parallel to the print direction. Finally, a multi-layered graft was bioprinted with horizontal filaments (XY plane) overlaying vertical filaments (Z-axis). The bioprinted tissue had an arcade-like collagen organization with horizontal collagen fibres overlaying vertical collagen fibres. These findings demonstrate how support baths can be used to provide spatially defined physical boundary conditions to bioprinted cells to guide matrix organization, enabling the engineering of anisotropic AC grafts. A) diagrammatic representation of physical boundaries directing collagen alignment of a confined bioink. The smaller the spacing X between the boundary the greater the neotissue collagen alignment. B) Utilizing an embedded 3D bioprinting support bath as a physical boundary to direct a biomimetic arcade-like collagen alignment in bioprinted anisotropic articular cartilage sheet. • Articular cartilage (AC) progenitors are superior to chondrocytes for AC engineering. • Physical boundaries direct the organization of extracellular matrix secreted by ACPs. • Greater physical confinement enhances cell and collagen alignment. • Support baths can provide spatially defined boundaries that direct tissue growth. • Physical boundaries support the bioprinting of anisotropic cartilage grafts.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it