Abstract Drug delivery systems have been employed to increase efficiency of scaffolds designed for tissue engineering targets, especially remediating an injury. One step even further is utilizing injectable materials to eliminate the need for a second injury in a less invasive manner. The aim of this study is preparation and evaluation of preformed injectable cryogel to overcome fluid leakage of in situ formed hydrogels. For this reason, gelatin was chosen as the main component to resemble the natural extracellular matrix. When it comes to drug nomination, betamethasone sodium phosphate was chosen since severe inflammation response is one of the main reasons for prolong healing. For drug delivery part, two different carriers namely cellulose nanocrystal (CNC) and polyamidoamine (PAMAM) dendrimer were used. It was hypothesized that these nanocarriers not only provide a sustained release of the drug but also boost up mechanical properties. Therefore, prepared samples were characterized chemically, physically and biologically. Based on the results, highly branched nanocarrier (i.e. PAMAM) showed better behavior in mechanical properties (E=14 kPa) and drug delivery (loading efficiency=70% and sustain release in 24 h) rather than nanorod carrier (i.e. CNC) with E=11kPa and 65% loading efficiency. However, both nanocarriers significantly decrease the rate of degradation almost two times. It seems likely the above mentioned properties as well as the advantage of high cell viability (99 % and 105% for CNC and PAMAM incorporated samples respectively) makes the prepared samples a useful alternatives for minimally invasive drug delivery as a tool for tissue engineering applications.

中文翻译：

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可注射载药明胶支架作为药物输送系统的微创方法：CNC / PAMAM 纳米颗粒

摘要 药物递送系统已被用于提高为组织工程靶点设计的支架的效率，尤其是修复损伤。更进一步的是利用可注射材料以较少侵入性的方式消除对二次伤害的需要。本研究的目的是制备和评估预成型的可注射冷冻凝胶，以克服原位形成的水凝胶的流体泄漏。出于这个原因，明胶被选为类似于天然细胞外基质的主要成分。在药物提名方面，选择倍他米松磷酸钠是因为严重的炎症反应是延长愈合的主要原因之一。对于药物递送部分，使用了两种不同的载体，即纤维素纳米晶 (CNC) 和聚酰胺胺 (PAMAM) 树枝状聚合物。据推测，这些纳米载体不仅可以提供药物的持续释放，还可以提高机械性能。因此，对制备的样品进行化学、物理和生物表征。基于结果，高度支化的纳米载体（即 PAMAM）在机械性能（E=14 kPa）和药物递送（负载效率 = 70% 和 24 小时内持续释放）方面表现出比具有 E 的纳米棒载体（即 CNC）更好的行为=11kPa 和 65% 的加载效率。然而，两种纳米载体都显着降低了降解率几乎两倍。