MacDonald Rebecca A, Voge Christopher M, Kariolis Mihalis, Stegemann Jan P
Department of Biomedical Engineering, Biotech-BMED 2, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180-3590, USA.
Acta Biomater. 2008 Nov;4(6):1583-92. doi: 10.1016/j.actbio.2008.07.005. Epub 2008 Jul 22.
Carbon nanotubes are attractive as additives in fiber-reinforced composites due to their high aspect ratio, strength and electrical conductivity. In the present study, solubilized collagen Type I was polymerized in the presence of dispersed single-walled carbon nanotubes (SWNT) and human dermal fibroblast cells (HDF) to produce collagen-SWNT composite biomaterials with HDF embedded directly in the matrix. The resulting constructs, with SWNT loadings of 0 (control), 0.8, 2.0 and 4.0 wt.% SWNT, were cultured and electrical properties were evaluated in the frequency range 5-500 kHz at days 3 and 7. All collagen-SWNT hydrogel matrices underwent HDF-mediated gel compaction over time in culture, but the presence of SWNT significantly decreased the rate and extent of gel compaction. Viability of HDF in all constructs was consistently high and cell morphology was not affected by the presence of SWNT. However, cell number at day 7 in culture decreased with increasing SWNT loading. Electrical conductivity of the constructs varied from 3 to 7 mS cm(-1), depending on SWNT loading level. Conductivity increased uniformly with increasing wt.% of SWNT (R=0.78) and showed a modest frequency dependence, suggesting that the electrical percolation threshold had not been reached in these materials. These data demonstrate that the electrical conductivity of cell-seeded collagen gels can be increased through the incorporation of carbon nanotubes. Protein-SWNT composite materials may have application as scaffolds for tissue engineering, as substrates to study electrical stimulation of cells, and as transducers or leads for biosensors.
由于具有高长径比、高强度和导电性，碳纳米管作为纤维增强复合材料的添加剂颇具吸引力。在本研究中，将溶解的I型胶原蛋白在分散的单壁碳纳米管（SWNT）和人皮肤成纤维细胞（HDF）存在的情况下进行聚合，以制备直接将HDF嵌入基质的胶原蛋白 - SWNT复合生物材料。所得构建体的SWNT负载量分别为0（对照）、0.8、2.0和4.0 wt.%，在第3天和第7天进行培养，并在5 - 500 kHz频率范围内评估其电学性质。随着培养时间的推移，所有胶原蛋白 - SWNT水凝胶基质都经历了HDF介导的凝胶压实，但SWNT的存在显著降低了凝胶压实的速率和程度。所有构建体中HDF的活力一直很高，细胞形态不受SWNT存在的影响。然而，培养第7天时细胞数量随着SWNT负载量的增加而减少。构建体的电导率在3至7 mS cm(-1)之间变化，具体取决于SWNT负载水平。电导率随SWNT wt.%的增加而均匀增加（R = 0.78），并且显示出适度的频率依赖性，这表明这些材料尚未达到电渗滤阈值。这些数据表明，通过掺入碳纳米管可以提高接种细胞的胶原蛋白凝胶的电导率。蛋白质 - SWNT复合材料可能具有作为组织工程支架、研究细胞电刺激的基质以及生物传感器的换能器或引线的应用。
