Jul 27, 2011
Surface hydrophilicity of carbon nanotube array affects protein delivery
Researchers from CSIRO Materials Science and Engineering, Australia, Nanyang Technological University, Singapore, and the University of Toronto, Canada, have demonstrated how the surface hydrophilicity of vertically aligned carbon nanotube arrays could affect the retention, release rate and bioactivity of rhBMP-2 – a growth factor that can stimulate the differentiation of human mesenchymal stem cells for bone regeneration and oral reconstruction.
Using an energetic ion beam, the team produced carbon nanotube arrays possessing similar microstructures, but vastly different surface hydrophilicity. This novel material provides a new platform for studying the complex interactions between biomolecules (for example, proteins) and carrier systems, and facilitates the design and development of advanced drug-delivery systems.
Retention and release
As shown in the images above, the pristine carbon nanotube arrays were superhydrophilic, but became superhydrophobic after energetic ion bombardment. When both arrays were used as carriers, the researchers found that the superhydrophilic versions retained a larger amount of rhBMP-2 than the superhydrophobic ones.
Use of a poloxamer diffusion layer on top of the loaded rhBMP-2 delayed the large initial burst that was commonly observed in conventional carriers and resulted in a greater total amount of rhBMP-2 released from both surfaces. Additionally, it was found that rhBMP-2 bound to the superhydrophilic carbon nanotube arrays remained bioactive while it denatured on the superhydrophobic arrays.
These properties could be considered for future development of next-generation drug-, gene- and protein-delivery systems to maximize their performance.
Full details can be found in the journal Nanotechnology.
About the author
Dr Zhao Jun Han is an OCE Science Leader Postdoctoral Fellow at Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, Australia. For more details e-mail Zhaojun.Han@csiro.au. His current research interests include the synthesis, modelling and applications of carbon nanotubes. Prof. Cher Ming Tan and Prof. Beng Kang Tay are based at the School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore. Dr Sean Peel is from the Department of Dentistry, University of Toronto, Canada. Prof. Kostya (Ken) Ostrikov is group leader of the PNCA. He is also the OCE Science Leader and Australian Future Fellow at CSIRO Materials Science and Engineering and an Honorary Professor at the University of Sydney, Australia.