Sreeja S, Parameshwar Ramesh, Varma P R Harikrishna, Sailaja G S
Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi, Kerala 682 022, India.
Division of Polymeric Medical Devices, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 011, India.
ACS Biomater Sci Eng. 2021 Feb 8;7(2):701-717. doi: 10.1021/acsbiomaterials.0c01628. Epub 2021 Jan 4.
A bifronted cure system for osteosarcoma, a common aggressive bone tumor, is highly in demand to prevail the postsurgical adversities in connection with systemic chemotherapy and repair of critical-size bone defects. The hierarchically porous therapeutic scaffolds presented here are synthesized by free radical-initiated copolymerization of hydroxyethyl methacrylate and methyl methacrylate [HEMA/MMA 80:20 and 90:10 mM, HO/NaCl porogen], which are further surface-phosphorylated [P-PHM] and transformed to bifunctional by impregnating doxorubicin (DOX) [DOXP-PHM]. The P-PHM scaffolds exhibited porous microarchitecture analogous to native cancellous bone (scanning electron microscopy analysis), while X-ray photoelectron spectroscopy analysis authenticated surface phosphorylation. Based on pore characteristics, swelling attributes and slow-pace degradation, P-PHM9163 and P-PHM8263 (HEMA/MMA 90:10 and 80:20 with HO/NaCl: 60/3.0 weight %, respectively) were chosen from the series and evaluated for osteoinductive efficacy . Both P-PHM9163 and P-PHM8263 invoked calcium phosphate mineralization in simulated physiological conditions (day 14) with Ca/P ratios of 1.58 and 1.66 respectively, comparable to human bone (1.67). Early biomineralization (Alizarin Red S and von Kossa staining) was evidenced at day 7, while osteoblast differentiation was verified by time-dependent expression of the typical late marker, osteocalcin, at day 14 and 21 in rat bone marrow mesenchymal cells. DOX-loaded P-PHM9163 (DOXP-PHM9163) exhibited pH-responsive (tumor analogous pH; 6.5) sustained release of DOX for prolonged time (up to 45 days) and invoked cellular alterations by cortical stress fiber formation and DNA fragmentation in human osteosarcoma cells leading to early apoptosis (24 h), validated by annexin V/PI staining (FACS) and immunostaining (F-actin/DAPI). Subsequent to DOX release tenure, the scaffold induced the formation of well-organized, porous post-release Ca-P apatite coating (Ca/P is 1.3) in simulated body fluid (day 14) which further endorses the dual functionality of the system. Altogether, the results accentuate that DOXP-PHM9163 is a potential bifunctional therapeutic scaffold capable of extended localized chemotherapeutic delivery in-line with inherent osteogenesis for efficient bone cancer treatment.
骨肉瘤是一种常见的侵袭性骨肿瘤，对于一种能够克服与全身化疗和关键尺寸骨缺损修复相关的术后不良情况的双前沿治疗系统有很高的需求。本文所展示的具有层次结构的多孔治疗支架是通过甲基丙烯酸羟乙酯和甲基丙烯酸甲酯[HEMA/MMA 80:20和90:10 mM，HO/NaCl致孔剂]的自由基引发共聚合成的，进一步进行表面磷酸化[P-PHM]，并通过浸渍阿霉素（DOX）转化为双功能[DOXP-PHM]。P-PHM支架呈现出类似于天然松质骨的多孔微结构（扫描电子显微镜分析），而X射线光电子能谱分析证实了表面磷酸化。基于孔隙特征、溶胀特性和缓慢降解，从该系列中选择了P-PHM9163和P-PHM8263（HEMA/MMA分别为90:10和80:20，HO/NaCl为60/3.0重量%）并评估其骨诱导功效。P-PHM9163和P-PHM8263在模拟生理条件下（第14天）均引发磷酸钙矿化，Ca/P比分别为1.58和1.66，与人骨（1.67）相当。在第7天有早期生物矿化（茜素红S和冯·科萨染色）的证据，而在大鼠骨髓间充质细胞中，在第14天和21天通过典型晚期标志物骨钙素的时间依赖性表达验证了成骨细胞分化。负载DOX的P-PHM9163（DOXP-PHM9163）表现出pH响应性（肿瘤类似pH；6.5）的DOX持续释放，持续时间长达45天，并通过人骨肉瘤细胞中皮质应力纤维形成和DNA片段化引发细胞改变，导致早期凋亡（24小时），通过膜联蛋白V/PI染色（流式细胞术）和免疫染色（F-肌动蛋白/DAPI）得到验证。在DOX释放期之后，支架在模拟体液中（第14天）诱导形成组织良好的多孔释放后Ca-P磷灰石涂层（Ca/P为1.3），这进一步证实了该系统的双功能性。总之，结果强调DOXP-PHM9163是一种潜在的双功能治疗支架，能够在进行有效的骨癌治疗时，与内在成骨作用一致地进行延长的局部化疗递送。
