Use of tendon to produce decellularized sheets of mineralized collagen fibrils for bone tissue repair and regeneration

Abstract

With demand for alternatives to autograft and allograft materials continuing to rise, development of new scaffolds for bone tissue repair and regeneration remains of significant interest. Engineered collagen‐calcium phosphate (CaP) constructs can offer desirable attributes, including absence of foreign body response and possession of inherent osteogenic potential. Despite their promise, current collagen‐CaP constructs are limited to nonload‐bearing applications. In this article, we describe a process for creating decellularized sheets of highly aligned, natively cross‐linked, and mineralized collagen fibrils, which may be useful for developing multilaminate collagen‐CaP constructs with improved mechanical properties. Decellularized bovine tendons were cryosectioned to produce thin sheets of aligned collagen fibrils. Mineralization of the sheets was then performed using an alternate soaking method incorporating a polymer‐induced liquid precursor (PILP) process to promote intrafibrillar mineralization, along with incorporation of physiologically relevant amounts of citrate, Mg, and carbonate. Characteristics of the produced scaffolds were assessed using energy‐dispersive X‐ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Scaffolds were also compared with both native bovine cortical bone and pure hydroxyapatite using X‐ray powder diffraction (XRD), and Fourier transform infrared spectroscopy attenuated total reflection (FTIR‐ATR). Structural and chemical analyses show that the scaffold preparation process that we described is successful in creating mineralized collagen sheets, possessing a mineral phase similar to that found in bone as well as a close association between collagen fibrils and mineral plates.

Decellularized extracellular matrix scaffolds: Recent trends and emerging strategies in tissue engineering

“…Third, dECM scaffolds preserve immunomodulatory cytokines, such as transforming growth factor-β, bone morphogenic proteins and bFGFs, which regulate the pro-inflammatory response [ 203 , [238] , [239] , [240] , [241] , [242] ]. In addition, the trace elements preserved in dECM, such as magnesium and strontium, play a crucial role in maintaining the integrity and cellular activity of bone [ 231 , 243 ]. To date, decellularized bone scaffolds are mainly derived from livestock animals due to their accessibility and similarity with human bone [ 233 , 235 , 237 ].…”

Surface-Directed Mineralization of Fibrous Collagen Scaffolds in Simulated Body Fluid for Tissue Engineering Applications

“…Collagen alone, as a template, is most likely not sufficient to initiate the nucleation of apatite to obtain crystals with peculiar size (nanoscopic), shape (plate-like), and alignment. , For instance, when collagen scaffolds are exposed to solutions supersaturated toward calcium phosphate (CaP), the ions tend to precipitate randomly in the vicinity of the fibril web, leading to large extrafibrillar spherulites in the best scenario. − …”

Preparation of mineralized pericardium by alternative soaking for soft–hard interregional tissue application

“…With alternate soaking, the quality, quantity, and distribution of calcification changed depending on the number of soaking cycles; thus, we examined calcification with various number of soaking cycles. Small granules were produced at a small number of soaking cycles and adsorbed onto the decellularized pericardium, covering the surface of the decellularized pericardium with an increase in number of cycles 27,34 owing to the aggregation rather than the growth of small granules because of the short soaking time of 10 s. In addition, preliminarily, when half of the pericardium was subjected to the alternative soaking process, the mineralization of pericardium was observed only in the soaked part (data not shown).…”

“…With alternate soaking, the quality, quantity, and distribution of calcification changed depending on the number of soaking cycles; thus, we examined calcification with various number of soaking cycles. Small granules were produced at a small number of soaking cycles and adsorbed onto the decellularized pericardium, covering the surface of the decellularized pericardium with an increase in number of cycles 27,34 owing to the aggregation rather than the growth of small granules because The ratio of calcium to phosphate also increased with the number of soaking cycles; Ca/P = 1.2-1.3 at 30 cycles, which is in the range of Ca/P of human bone, 1.19 to 2.28. 35,36 Various forms of calcium phosphate, such as octacalcium phosphate, amorphous calcium phosphate, calcium-deficient, precipitated, carbonate-containing apatite, and heavily carbonated hydroxyapatite, can be obtained using different mineralization methods.…”