Surface phthaloylation of chitin nanofiber in aqueous media to improve dispersibility in aromatic solvents and give thermo-responsive and ultraviolet protection properties

Ifuku, Shinsuke; Suzuki, Naoto; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki

doi:10.1039/c4ra01975j

Cited by 22 publications

(9 citation statements)

References 18 publications

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“…CNF, CCNF and CNC are, therefore, hydrophilic and water dispersible compounds. For detailed information on the preparation of chitin nanomaterials, please see previous papers (Gopalan Nair and Dufresne, ; Ifuku et al, ). In comparison with the TEM data, the DLS measurements gave much larger sizes for the six nanomaterials.…”

Section: Methodsmentioning

confidence: 99%

Salinity‐dependent toxicity of water‐dispersible, single‐walled carbon nanotubes to Japanese medaka embryos

Kataoka

Nakahara

Shimizu

et al. 2016

J of Applied Toxicology

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To investigate the effects of salinity on the behavior and toxicity of functionalized single-walled carbon nanotubes (SWCNTs), which are chemical modified nanotube to increase dispersibility, medaka embryos were exposed to non-functionalized single-walled carbon nanotubes (N-SWCNTs), water-dispersible, cationic, plastic-polymer-coated, single-walled carbon nanotubes (W-SWCNTs), or hydrophobic polyethylene glycol-functionalized, single-walled carbon nanotubes (PEG-SWCNTs) at different salinities, from freshwater to seawater. As reference nanomaterials, we tested dispersible chitin nanofiber (CNF), chitosan-chitin nanofiber (CCNF) and chitin nanocrystal (CNC, i.e. shortened CNF). Under freshwater conditions, with exposure to 10 mg l W-SWCNTs, the yolk sacks of 57.8% of embryos shrank, and the remaining embryos had a reduced heart rate, eye diameter and hatching rate. Larvae had severe defects of the spinal cord, membranous fin and tail formation. These toxic effects increased with increasing salinity. Survival rates declined with increasing salinity and reached 0.0% in seawater. In scanning electron microscope images, W-SWCNTs, CNF, CCNF and CNC were adsorbed densely over the egg chorion surface; however, because of chitin's biologically harmless properties, only W-SWCNTs had toxic effects on the medaka eggs. No toxicity was observed from N-SWCNT and PEG-SWCNT exposure. We demonstrated that water dispersibility, surface chemistry, biomedical properties and salinity were important factors in assessing the aquatic toxicity of nanomaterials. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Salinity‐dependent toxicity of water‐dispersible, single‐walled carbon nanotubes to Japanese medaka embryos

Kataoka

Nakahara

Shimizu

et al. 2016

J of Applied Toxicology

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“…Several chemical modifications of chitin NF surfaces were achieved: acetylation [36], deacetylation [41], phthaloylation [42], naphthaloylation [43], maleylation [43], chlorination [46], TEMPO-mediated oxidation [50], and graft polymerization [51]. Modification is a promising and effective way to design functional materials.…”

Section: Discussionmentioning

confidence: 99%

“…High cationic charges appeared on the chitin surfaces in high density in acidic water; this is significant for effective disintegration. [42,43] In chitosan chemistry, N-phthaloylation using phthalic anhydride is the most important protection reaction of the amino group [44]. Recently, highly chemoselective and quantitative N-phthaloylation of chitosan in aqueous media has been accomplished [45].…”

Section: Acetylation Of Chitin Nanofibersmentioning

confidence: 99%

Chitin and Chitosan Nanofibers: Preparation and Chemical Modifications

2014

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Chitin nanofibers are prepared from the exoskeletons of crabs and prawns, squid pens and mushrooms by a simple mechanical treatment after a series of purification steps. The nanofibers have fine nanofiber networks with a uniform width of approximately 10 nm. The method used for chitin-nanofiber isolation is also successfully applied to the cell walls of mushrooms. Commercial chitin and chitosan powders are also easily converted into nanofibers by mechanical treatment, since these powders consist of nanofiber aggregates. Grinders and high-pressure waterjet systems are effective for disintegrating chitin into nanofibers. Acidic conditions are the key factor to facilitate mechanical fibrillation. Surface modification is an effective way to change the surface property and to endow nanofiber surface with other properties. Several modifications to the chitin NF surface are achieved,

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“…The highly reactive free amino group offers a facile surface modification of chitin NC under relatively homogeneous reaction conditions. Recently, we have reported the N-phthaloylation in water to the partially deacetylated chitin nanofiber (Ifuku, Suzuki, Izawa, Morimoto, & Saimoto, 2014). The phthaloyl group was quantitatively introduced into the chitin via strong imido linkage.…”

Section: Introductionmentioning

confidence: 99%

Preparation of zwitterionically charged nanocrystals by surface TEMPO-mediated oxidation and partial deacetylation of α-chitin

Ifuku

Hori

Izawa

et al. 2015

Carbohydrate Polymers

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Surface phthaloylation of chitin nanofiber in aqueous media to improve dispersibility in aromatic solvents and give thermo-responsive and ultraviolet protection properties

Cited by 22 publications

References 18 publications

Salinity‐dependent toxicity of water‐dispersible, single‐walled carbon nanotubes to Japanese medaka embryos

Salinity‐dependent toxicity of water‐dispersible, single‐walled carbon nanotubes to Japanese medaka embryos

Chitin and Chitosan Nanofibers: Preparation and Chemical Modifications

Preparation of zwitterionically charged nanocrystals by surface TEMPO-mediated oxidation and partial deacetylation of α-chitin

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