Protein alignment using cellulose nanocrystals: practical considerations and range of application

Abstract

Cellulose nanocrystals (CNCs) form liquid crystals in aqueous solution that confer alignment to macromolecules and permit the measurement of residual dipolar couplings. CNCs possess many attractive features as an alignment medium. They are inexpensive, non-toxic, chemically inert, and robust to denaturants and temperature. Despite these advantages, CNCs are seldom employed as an alignment medium and the range of their applicability has not yet been explored. We have re-examined the use of CNCs in biomolecular NMR by analyzing the effects concentration, ionic strength, and temperature on molecular alignment. Stable alignment was obtained over wide ranges of temperature (10-70 degrees C) and pH (2.5-8.0), which makes CNCs potentially very useful in studies of thermophilic proteins and acid-stabilized molecules. Notably, we find that CNC suspensions are very sensitive to the concentrations of biological buffers, which must be taken into account when they are used in NMR analyses. These results have led us to develop a general procedure for preparing aligned samples with CNCs. Using the SH3 domain from the Fyn tyrosine kinase as a model system, we find that CNCs produce an alignment frame collinear with that of the commonly used Pf1 bacteriophage alignment medium, but of opposite magnitude.

Domain cooperativity in multidomain proteins: what can we learn from molecular alignment in anisotropic media?

“…This situation is observed in stretched vs. compressed gels, 61, 62 conventional vs. `flipped' bicelles, 63, 64 and other similar systems. 65 Although NSP defined by Eq. (3) depends also on rhombicity R , it is mainly a measure of alignment axes orientation.…”

Cellulose nanofiber–titania nanocomposites as potential drug delivery systems for dermal applications

“…Nanocomposites based on nanocellulose, nano-or microfibrilliar cellulose, cellulose nanofibers are new generation nanomaterials possessing wide range of practical applications in such domains as pharmacology 1 and medicine 2 , tissue engineering [3][4][5] , biosensors 6 , microfluidics elements 7 , materials for microencapsulation 8 and drug delivery [9][10][11][12] , as permoselective membranes 13 , and as a barrier to protect mucosal tissues 14,15 . The nanoscale cellulose possesses a whole complex of unique properties typical for nanomaterials in general, such as high specific surface area, enhanced chemical reactivity, high mechanical durability, together with biocompatibility, biodegradability, and non-toxicity, which make it an excellent candidate for drug release applications.…”

Controlling the Photonic Properties of Cholesteric Cellulose Nanocrystal Films with Magnets

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a variety of parameters. [28,30,31] While the use of external fields, such as electric [32][33][34] and magnetic, [29,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] have been shown to provide a powerful control over the CNC orientation in suspensions, they have been so far considered impractical as a tool to tailor the photonic pro perties of the films. Therefore, the manipulation of the orientation of the helix m has so far not been addressed, or was at best limited to favor its vertical orientation uniformly across the sample.

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“…Therefore, the manipulation of the orientation of the helix m has so far not been addressed, or was at best limited to favor its vertical orientation uniformly across the sample. [28,30,31] While the use of external fields, such as electric [32][33][34] and magnetic, [29,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] have been shown to provide a powerful control over the CNC orientation in suspensions, they have been so far considered impractical as a tool to tailor the photonic pro perties of the films. More specifically, it has been believed for over two decades that the magnetic orientation of the cholesteric phase in CNC suspensions required always very strong fields (≥5 T), which probably discouraged many from investigating this method, due to the seemingly limited applicability and thus relevance of this technique to produce useful aligned CNC-based materials.…”