Recellularization and Integration of Dense Extracellular Matrix by Percolation of Tissue Microparticles

Abstract

Cells embedded in the extracellular matrix of tissues play a critical role in maintaining homeostasis while promoting integration and regeneration following damage or disease. Emerging engineered biomaterials utilize decellularized extracellular matrix as a tissue-specific support structure; however, many dense, structured biomaterials unfortunately demonstrate limited formability, fail to promote cell migration, and result in limited tissue repair. Here, a reinforced composite material of densely packed acellular extracellular matrix microparticles in a hydrogel, termed tissue clay, that can be molded and crosslinked to mimic native tissue architecture is developed. Hyaluronic acid-based hydrogels are utilized, amorphously packed with acellular cartilage tissue particulated to ≈125-250 microns in diameter and defined a percolation threshold of 0.57 (v/v) beyond which the compressive modulus exceeded 300 kPa. Remarkably, primary chondrocytes recellularize particles within 48 h, a process driven by chemotaxis, exhibit distributed cellularity in large engineered composites, and express genes consistent with native cartilage repair. In addition, broad utility of tissue clays through recellularization and persistence of muscle, skin, and cartilage composites in an in vivo mouse model is demonstrated. The findings suggest optimal material architectures to balance concurrent demands for large-scale mechanical properties while also supporting recellularization and integration of dense musculoskeletal and connective tissues.

Cartilage Formation In Vivo Using High Concentration Collagen-Based Bioink with MSC and Decellularized ECM Granules

“…There are few works that describe the use of the powder directly as functional addition. In two of them [ 46 , 47 ], fresh cartilage particles or dECM obtained from articular cartilage were used as microcarriers for the cultivation of bone marrow stromal cells (BMSC) and chondrocytes. Moreover, if, in the work of J. Barthold et al [ 46 ], dECM powder was added to hyaluronic acid-based hydrogel and cell migration to the granules was observed, then, in the study conducted by H. Yin et al [ 47 ], BMSC differentiated into mature chondrocytes was achieved in 21 days without the use of exogenous growth factors.…”

“…In two of them [ 46 , 47 ], fresh cartilage particles or dECM obtained from articular cartilage were used as microcarriers for the cultivation of bone marrow stromal cells (BMSC) and chondrocytes. Moreover, if, in the work of J. Barthold et al [ 46 ], dECM powder was added to hyaluronic acid-based hydrogel and cell migration to the granules was observed, then, in the study conducted by H. Yin et al [ 47 ], BMSC differentiated into mature chondrocytes was achieved in 21 days without the use of exogenous growth factors. In another study [ 48 ], human periosteal cell and demineralized bone granules (250–500 μm) were successfully used to induce the cells’ osteoinductive potential without any growth factors in the collagen-based scaffold.…”

“…However, the data on the proper size of the particles are contradictory. Large granules (from 250 µm) can function as microcarriers [ 46 , 47 ]. From the point of view of bioink homogeneity and better printability, the particles should be smaller: no more than 50 µm [ 38 ].…”

New Insights into Cartilage Tissue Engineering: Improvement of Tissue-Scaffold Integration to Enhance Cartilage Regeneration

“…It has been shown that combination of decellularized matrices with chondrocytes or other appropriate cell types would promote higher CSI in comparison to decellularized matrix alone [ 31 , 32 ]. Barthold et al demonstrated that recruiting ECM microparticles embedded in hyaluronic acid (HA) hydrogel improves chondrocyte migration through chemotaxis and so resulted in tissue integration [ 33 ]. It seems that strategies which promote collagen deposition by direct cell recruitment or indirect stimulation of cell migration would result in greater scaffold-cartilage integration.…”

Epigenetic Priming Enhances Chondrogenic Potential of Expanded Chondrocytes for Cartilage Repair

“…We isolated total RNA and reverse transcribed the RNA to cDNA from both 3D and 2D cultures to assess relative gene expression using RT-qPCR with previously described techniques 21 . All primers were designed (sequences listed in Table 1) using NCBI Primer BLAST, ensuring that primers were separated by at least one intron and IDT performed the synthesis of primers.…”