Laser-structured bacterial nanocellulose hydrogels support ingrowth and differentiation of chondrocytes and show potential as cartilage implants

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• 作者：Hannes Ahrem ; David Pretzel ; Michaela Endres ; Daniel Conrad ; Julien Courseau ; Hartmut M眉ller ; Raimund Jaeger ; Christian Kaps ; Dieter O. Klemm ; Raimund W. Kinne
• 关键词：Bacterial nanocellulose ; Microbial cellulose ; Laser structuring ; Chondrocyte ingrowth/differentiation ; Cartilage implant
• 刊名：Acta Biomaterialia
• 出版年：March, 2014
• 年：2014
• 卷：10
• 期：3
• 页码：1341-1353
• 全文大小：3870 K

文摘

The small size and heterogeneity of the pores in bacterial nanocellulose (BNC) hydrogels limit the ingrowth of cells and their use as tissue-engineered implant materials. The use of placeholders during BNC biosynthesis or post-processing steps such as (touch-free) laser perforation can overcome this limitation. Since three-dimensionally arranged channels may be required for homogeneous and functional seeding, three-dimensional (3-D) laser perforation of never-dried BNC hydrogels was performed. Never-dried BNC hydrogels were produced in different shapes by: (i) the cultivation of Gluconacetobacter xylinus (DSM 14666; synonym Komagataeibacter xylinus) in nutrient medium; (ii) the removal of bacterial residues/media components (0.1 M NaOH; 30 min; 100 掳C) and repeated washing (deionized water; pH 5.8); (iii) the unidirectional or 3-D laser perforation and cutting (pulsed CO₂ Rofin SC 脳10 laser; 220 渭m channel diameter); and (iv) the final autoclaving (2 M NaOH; 121 掳C; 20 min) and washing (pyrogen-free water). In comparison to unmodified BNC, unidirectionally perforated - and particularly 3-D-perforated - BNC allowed ingrowth into and movement of vital bovine/human chondrocytes throughout the BNC nanofiber network. Laser perforation caused limited structural modifications (i.e. fiber or globular aggregates), but no chemical modifications, as indicated by Fourier transform infrared spectroscopy, X-ray photoelectron scattering and viability tests. Pre-cultured human chondrocytes seeding the surface/channels of laser-perforated BNC expressed cartilage-specific matrix products, indicating chondrocyte differentiation. 3-D-perforated BNC showed compressive strength comparable to that of unmodified samples. Unidirectionally or 3-D-perforated BNC shows high biocompatibility and provides short diffusion distances for nutrients and extracellular matrix components. Also, the resulting channels support migration into the BNC, matrix production and phenotypic stabilization of chondrocytes. It may thus be suitable for in vivo application, e.g. as a cartilage replacement material.