Dense collagen (DC) gels facilitate the osteoblastic differentiation of seeded dental pulp stem cells (DPSCs) and undergo rapid acellular mineralization when incorporated with bioactive glass particles, both in vitro and subcutaneously in vivo. However, the potential of DC-bioactive glass hybrid gels in delivering DPSCs for bone regeneration in an osseous site has not been investigated. In this study, the efficacy of both acellular and DPSC-seeded DC-S53P4 bioactive glass [(53)SiO₂-(23)Na₂O-(20)CaO-(4)P₂O₅, wt%] hybrid gels was investigated in a critical-sized murine calvarial defect. The incorporation of S53P4, an osteostimulative bioactive glass, into DC gels led to accelerated acellular mineralization in simulated body fluid (SBF), in vitro, where hydroxycarbonated apatite was detected within 1 day. By day 7 in SBF, micro-mechanical analysis demonstrated an 8-fold increase in the compressive modulus of the mineralized gels. The in-situ effect of the bioactive glass on human-DPSCs within DC-S53P4 was evident, by their osteogenic differentiation in the absence of osteogenic supplements. The production of alkaline phosphatase and collagen type I was further increased when cultured in osteogenic media. This osteostimulative effect of DC-S53P4 constructs was confirmed in vivo, where after 8 weeks implantation, both acellular scaffolds and DPSC-seeded DC-S53P4 constructs formed mineralized and vascularized bone matrices with osteoblastic and osteoclastic cell activity. Surprisingly, however, in vivo micro-CT analysis confirmed that the acellular scaffolds generated larger volumes of bone, already visible at week 3 and exhibiting superior trabecular architecture. The results of this study suggest that DC-S53P4 scaffolds negate the need for stem cell delivery for effective bone tissue regeneration and may expedite their path towards clinical applications.

密集的胶原蛋白（DC）凝胶可促进种子牙髓干细胞（DPSC）的成骨细胞分化，并在体外和皮下体内与生物活性玻璃颗粒结合后经历快速的无细胞矿化作用。然而，尚未研究DC-生物活性玻璃杂化凝胶在输送DPSC中用于骨部位骨再生的潜力。在这项研究中，无细胞和接种DPSC的DC-S53P4生物活性玻璃[（53）SiO _2-（23）Na ₂ O-（20）CaO-（4）P ₂ O ₅的功效，wt％]杂化凝胶在临界大小的小鼠颅盖缺损中进行了研究。将S53P4（一种具有骨刺激性的生物活性玻璃）掺入DC凝胶后，在体外模拟体液（SBF）中加速了脱细胞矿化作用，其中在1天内检测到了碳酸羟基磷灰石。到SBF的第7天，微机械分析表明，矿化凝胶的压缩模量提高了8倍。在原位上DC-S53P4内人牙髓干细胞的生物活性玻璃的效果是明显的，在不存在成骨补充物的它们的成骨分化。在成骨培养基中培养时，碱性磷酸酶和I型胶原的产生进一步增加。证实了DC-S53P4构建体的这种骨刺激作用在体内，植入8周后，无细胞支架和接种DPSC的DC-S53P4构建体均形成具有成骨细胞和破骨细胞活性的矿化和血管化骨基质。然而，令人惊讶的是，体内微CT分析证实，脱细胞支架产生的骨量更大，在第3周时就已经可见，并显示出优越的小梁结构。这项研究的结果表明，DC-S53P4支架消除了干细胞递送以实现有效的骨组织再生的需要，并可能加快其走向临床应用的道路。