Bioprinted living tissue constructs with layer-specific, growth factor-loaded microspheres for improved enthesis healing of a rotator cuff

Co-Culture of Mesenchymal Stem Cells and Ligamentocytes on Triphasic Embroidered Poly(L-lactide-co-ε-caprolactone) and Polylactic Acid Scaffolds for Anterior Cruciate Ligament Enthesis Tissue Engineering

“…At this point, it should be mentioned that this is the first approach to show the feasibility of co-culturing osteogenically induced and ligamentogenic cell types on a novel multiphasic cell carrier, and therefore multifaceted analysis, including qualitative vitality assay, immunocytochemistry, calculation of DNA and GAG contents, real-time PCR and classical histological staining were performed but certainly not all possible methods (such as transcriptome analysis, single-cell RNA sequencing or fluorescence in situ hybridization [ 76 ]) have been applied to investigate the full breadth and depth of the matter. Vitality assay was only performed in a qualitative way, similar to other authors [ 32 , 68 , 71 ], to acquire not only a direct answer regarding cell vitality after culturing, but also to visualize and localize exactly which cells are still alive. Hence, so far no qualitative vitality analysis, such as the Presto Blue Assay [ 33 ], the ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) Assay [ 77 ] or the fluorescent Alamar Blue Assay, was included, which will be performed in future.…”

“…The osteogenically differentiated spheroids in long-term culture were still able to express the important bone ECM components such as collagen type I and the hypertrophic marker collagen type X. A detailed observation of further markers (such as alkaline phosphatase [ 98 ], bone sialoprotein [ 33 , 93 ], osteocalcin [ 98 ], osteonectin [ 32 ], osteopontin [ 99 ], collagen type V [ 100 , 101 ] and the bone-specific transcription factor bone-morphogenic protein 2 [ 102 ]) will be performed in future. Since these two ECM components could also be detected in non-differentiated hMSC spheroids (directly colonized), it can be assumed that the scaffolds also have an osteoconductive influence due to their collagen foam functionalization [ 103 ].…”

“…Using embroidery technology, especially medical lace embroidery, as a scaffold fabrication technique seemed to be a promising methodology in this reconstructive tissue engineering field to achieve a mechanically resilient and zonal tissue [ 30 ]. Compared to other methods such as 3D bioprinting [ 31 , 32 ], electrospinning [ 33 , 34 , 35 ] or braiding [ 36 ], medical lace embroidery works with the interlacing of highly oriented thread materials and therefore enables the fabrication of stress-adapted structures [ 37 ]. The synthetic materials poly( l -lactide-co-ε-caprolactone) (P(LA-CL)) and polylactic acid (PLA) used in the present study are well established in the medical field [ 38 , 39 ] and also proven to be cyto- and biocompatible after functionalization [ 40 , 41 , 42 ].…”

Understanding Fibrous Tissue in the Effective Healing of Rotator Cuff Injury

“…Different strategies used for preparing scaffolds include electrospinning [ 97 – 100 ], a 3D-bioprinting [ 89 , 101 , 102 ], hydrogels [ 103 – 106 ], microspheres [ 102 , 107 ] and decellularized matrices [ 108 – 110 ]. The biomaterials used in these methods include both natural and synthetic.…”

Immunomodulatory multicellular scaffolds for tendon-to-bone regeneration

“…Although the healing effect of tendon-to-bone injuries has been improved, the formation of scar structures at the interface and limited motor function is still inevitable ( 1 , 5 ). One of the major reasons for this is that most of the biomaterials developed by researchers only focus on augmenting the biological functions directly related to tendon-to-bone ( 16 , 17 ), such as osteogenic differentiation or tenogenic differentiation, while ignoring the effect of the three-dimensional (3D) microenvironment surrounding the injury site, especially inflammatory responses triggered by immune cells in vivo ( 12 , 18 , 19 ). Among various immune cells, macrophages have received increasing attention in tendon-to-bone injury since they are closely associated with tendon fibrosis ( 20 , 21 ).…”