Qureshi Ammar T, Terrell Lekeith, Monroe W Todd, Dasa Vinod, Janes Marlene E, Gimble Jeffrey M, Hayes Daniel J
Department of Agricultural and Biological Engineering, Louisiana State University and Agricultural Center, Baton Rouge, LA, USA.
J Tissue Eng Regen Med. 2014 May;8(5):386-95. doi: 10.1002/term.1532. Epub 2012 Jun 15.
Nationally, nearly 1.5 million patients in the USA suffer from ailments requiring bone grafts and hip and other joint replacements. Infections following internal fixation in orthopaedic trauma can cause osteomyelitis in 22-66% of cases and, if uncontrolled, the mortality rate can be as high as 2%. We characterize a procedure for the synthesis of antimicrobial and biocompatible poly-l-lactic acid (PLLA) and poly-ethyleneglycol (PEG) bioscaffolds designed to degrade and absorb at a controlled rate. The bioscaffold architecture aims to provide a suitable substrate for the controlled release of silver nanoparticles (SNPs) to reduce bacterial growth and to aid the proliferation of human adipose-derived stem cells (hASCs) for tissue-engineering applications. The fabricated bioscaffolds were characterized by scanning transmission microscope (SEM) and it showed that the addition of tncreasing concentrations of SNPs results in the formation of dendritic porous channels perpendicular to the axis of precipitation. The antimicrobial properties of these porous bioscaffolds were tested according to a modified ISO 22196 standard across varying concentrations of biomass-mediated SNPs to determine an efficacious antimicrobial concentration. The bioscaffolds reduced the Staphylococcus aureus and Escherichia coli viable colony-forming units by 98.85% and 99.9%, respectively, at an antimicrobial SNPs concentration of 2000 ppm. Human ASCs were seeded on bioscaffolds and cultured in vitro for 20 days to study the effect of SNPs concentration on the viability of cells. SEM analysis and the metabolic activity-based fluorescent dye, AlamarBlue®, demonstrated the growth of cells on the efficacious antimicrobial bioscaffolds. The biocompatibility of in vitro leached silver, quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES), proved non-cytotoxic when tested against hASCs, as evaluated by MTT assay.
在美国，全国范围内有近150万患者患有需要骨移植以及髋关节和其他关节置换的疾病。骨科创伤内固定术后感染在22%至66%的病例中可导致骨髓炎，若感染得不到控制，死亡率可高达2%。我们描述了一种合成抗菌且生物相容的聚左旋乳酸（PLLA）和聚乙二醇（PEG）生物支架的方法，该生物支架设计为以可控速率降解和吸收。生物支架结构旨在为银纳米颗粒（SNP）的控释提供合适的基质，以减少细菌生长，并有助于人脂肪来源干细胞（hASC）增殖用于组织工程应用。通过扫描透射显微镜（SEM）对制备的生物支架进行表征，结果表明，随着SNP浓度增加，会形成垂直于沉淀轴的树枝状多孔通道。根据修改后的ISO 22196标准，在不同浓度的生物量介导的SNP条件下测试这些多孔生物支架的抗菌性能，以确定有效的抗菌浓度。在抗菌SNP浓度为2000 ppm时，生物支架分别使金黄色葡萄球菌和大肠杆菌的活菌落形成单位减少了98.85%和99.9%。将人ASC接种在生物支架上并在体外培养20天，以研究SNP浓度对细胞活力的影响。SEM分析和基于代谢活性的荧光染料AlamarBlue®证明了细胞在有效的抗菌生物支架上生长。通过电感耦合等离子体发射光谱法（ICP-OES）对体外浸出银的生物相容性进行定量，经MTT法评估，在针对hASC进行测试时证明无细胞毒性。
