Cilia-Mimetic Hairy Surfaces Based on End-Immobilized Nanocellulose Colloidal Rods
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- 作者：Arcot R. Lokanathan ; Antti Nyk盲nen ; Jani Seitsonen ; Leena-Sisko Johansson ; Joseph Campbell ; Orlando J. Rojas ; Olli Ikkala ; Janne Laine
- 刊名：Biomacromolecules
- 出版年：2013
- 出版时间：August 12, 2013
- 年：2013
- 卷：14
- 期：8
- 页码：2807-2813
- 全文大小：492K
- 年卷期：v.14,no.8(August 12, 2013)
- ISSN：1526-4602
文摘
We show a simple method toward nanoscale cilia-like structures, i.e., functional hairy surfaces, upon topochemically functionalizing nanorods of cellulose nanocrystals (CNCs) with thiol end groups (CNC-SHs), which leads to their immobilization onto a gold surface from one end, still allowing their orientational mobility. CNCs having a lateral dimension of 3鈥? nm and length of 50鈥?00 nm incorporate the native crystalline structure with hydrogen-bonded cellulose chains in the parallel configuration. This facilitates asymmetric, selective chemical modification of the reducing ends through reductive amination. Successful thiol functionalization is demonstrated using cryo transmission electron microscopy based on selective attachment of silver nanoparticles to the CNC-SH ends to form Janus-like colloidal rod鈥搒phere adducts. The extent of thiol modification of CNC-SHs is quantified using X-ray photoelectron spectroscopy. The promoted binding of CNC-SHs on gold surfaces is shown by atomic force microscopy and quartz crystal microbalance, where the high dissipation suggests pronounced orientational mobility due to flexible joints at one rod end onto the surfaces. That the joints are flexible is also shown by the bending and realignment of the CNC-SH rods using a receding triple-phase evaporation front of a drying drop of water. The ability of the hairy surface to size-selectively resist particle binding was also investigated. As the CNCs are piezoelectric and allow magnetic functionalization by nanoparticles, we foresee a general platform for nanosized artificial cilia for fluid manipulation and controlled adsorption/desorption.