Facile Approach for the Dispersion of Regenerated Cellulose in Aqueous System in the Form of Nanoparticles

This study reports a facile method to disperse cellulose in deionized water, wherein a critical condition of regenerated cellulose is discovered, where it completely disperses up to a maximum of 5 g L^–1 concentration in deionized water with the help of ultrasonication. The dispersed cellulose is characterized by TEM and DLS, the latter among which shows 200 nm hydrodynamic radii of cellulose nanoparticles dispersed in deionized water. FTIR analysis of dispersed cellulose reveals that dispersed cellulose losses its crystallinity during regeneration and dispersion step employed in this study. The dispersed cellulose reported in this study is able to form free-standing, transparent films, which were characterized by SEM, XRD, TGA, EDX, and FTIR spectroscopy and show resistance against dissolution in water. Additionally, the dispersed cellulose is able to undergo at least three times faster enzymatic hydrolysis in comparison to pristine microcrystalline cellulose under similar reaction conditions. The dispersed cellulose reported here could be a better material for reinforcement, preparation of hydrogels, and drug delivery applications under physiological environment

SEM images of silica structures synthesized by hydrolysis of 1 mM TEOS using 10 mM equivalent of (a–b) ammonia, and (c–d) L-serine amino acid in ionic liquid [BMIM][BF₄].

<p>SEM images of silica structures synthesized by hydrolysis of 1 mM TEOS using 10 mM equivalent of (a–b) ammonia, and (c–d) L-serine amino acid in ionic liquid [BMIM][BF₄].</p

SEM images of found in nature that have some resemblance to silica structures synthesized by cationic amino acid in ionic liquid [BMIM][BF₄].

<p>(a) <i>Isthima nervosa</i>, (b) <i>Cyclotella meneghiniana</i>, and (c) <i>Trigonium arcticum</i>. Reproduced by permission from <i>Trends in Biotechnology</i> [Drum R and Gordon R (2003) Star Trek replicators and diatom nanotechnology. <i>Trends Biotechnol</i> 21: 325–328]</p

SEM images of silica structures synthesized using arginine in IL [BMIM][BF₄] involving TEOS to arginine molar ratios of (a and b) 1∶10, (c) 1∶1, and (d) 1∶0.2 respectively.

<p>The insets show the higher magnification images of the structures shown in the corresponding main figure.</p

SEM images of silica structures synthesized using lysine in IL [BMIM][BF₄] involving TEOS to lysine molar ratios of (a and b) 1∶10, (c) 1∶1, and (d) 1∶0.2 respectively.

<p>The insets show the higher magnification images of the structures shown in the corresponding main figure.</p

XPS spectra showing Si 2p (a–c) and O 1s (d–f) core levels arising from SiO2 structures synthesized using 10 mM of lysine (a, d); arginine (b, e); and histidine (c, f) respectively.

<p>XPS spectra showing Si 2p (a–c) and O 1s (d–f) core levels arising from SiO2 structures synthesized using 10 mM of lysine (a, d); arginine (b, e); and histidine (c, f) respectively.</p

Self-Assembled Functional Nanostructure of Plasmid DNA with Ionic Liquid [Bmim][PF₆]: Enhanced Efficiency in Bacterial Gene Transformation

The electrostatic interaction between the negatively charged phosphate groups of plasmid DNA and the cationic part of hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]­[PF₆]), initiates spontaneous self-assembly to form the functional nanostructures made up of DNA and ionic liquid (IL). These functional nanostructures were demonstrated as promising synthetic nonviral vectors for the efficient bacterial pGFP gene transformation in cells. In particular, the functional nanostructures that were made up of 1 μL of IL ([Bmim]­[PF₆]) and 1 μg of plasmid DNA can increase the transformation efficiency by 300–400% in microbial systems, without showing any toxicity for <i>E. coli</i> DH5α cells. ³¹P nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron (XPS) spectroscopic analysis revealed that the electrostatic interaction between negatively charged phosphate oxygen and cationic Bmim⁺ tends to initiate the self-assembly process. Thermogravimetric analysis of the DNA-IL functional nanostructures showed that these nanostructures consist of ∼16 wt % ionic liquid, which is considered to provide the stability to the plasmid DNA that eventually enhanced the transformation efficiency

Selected area electron diffraction (SAED) patterns obtained from silica superstructures obtained in ionic liquid [BMIM][BF₄] by hydrolysis of 1 mM TEOS using 10 mM of cationic amino acids (a) L-lysine, (b) L-arginine, and (c) L-histidine respectively.

<p>The diffused ring patterns are either from the TEM grid coated with an amorphous carbon film, and/or from the amorphous silica superstructures.</p

SEM images of silica structures synthesized using histidine in IL [BMIM][BF₄] involving TEOS to histidine molar ratios of (a and b) 1∶10, (c) 1∶1, and (d) 1∶0.2 respectively.

<p>The insets show the higher magnification images of the structures shown in the corresponding main figure.</p