Effects of ionic strength on the size and compactness of chitosan nanoparticles

Abstract

In this work, chitosan nanoparticles were prepared by ionotropic gelation of chitosan with tripolyphosphate (TPP). The effects of the ionic strength of the solvent employed in the particle preparation on the average size and compactness of the particles were investigated. In addition, the effects of the chitosan concentration and the crosslinker to polymer ratio on the particle characteristics were studied. The chitosan-TPP nanoparticles were characterized by dynamic light scattering, zeta potential, and turbidity measurements. The compactness of the nanoparticles was estimated with a method based on the size of the nanoparticles and the turbidity of the nanoparticle suspension. All the investigated preparation parameters, i.e., the ionic strength of the solvent, the chitosan concentration, and the TPP to chitosan ratio, affected the particle characteristics. For instance, smaller and more compact particles were formed in saline solvents, compared to particles formed in pure water. Further, the addition of monovalent salt rendered it possible to prepare particles in the nanometer size range at a higher polymer concentration. Solvent salinity is thus an important parameter to address in the preparation of chitosan nanoparticles crosslinked with TPP.

Factors affecting the stability of chitosan/tripolyphosphate micro- and nanogels: resolving the opposing findings

“…14 These conditions were in stark contrast to the salt effect studies conducted by others, 26,27,44 where much higher 0.05 -0.1 wt% final chitosan concentrations and DD-values that exceeded 90% were used. Thus, the seemingly conflicting findings on the salt effects appear to be reconciled by the present study.…”

Design and characterization of chitosan-based composite particles with tunable interfacial properties

“…Scheme 2A)(Jonassen, et al, 2012a, Jonassen, et al, 2012b. Therefore, the10 average size of NMPs increase and these results demonstrate opposite trends from other Huang and Lapitsky, 2011, Jonassen, et al, 2012a, Jonassen, et al, 2012b).…”

Schizophrenic micellization in aqueous solutions of the pH- and temperature responsive pentablock terpolymer PDEAEMAx-b-PNIPAAMy-b-PEGz-b-PNIPAAMy-b-PDEAEMAx

“…Directly above the sample, an optical system with a light-scattering detector continuously monitored the scattered intensity signal (S) of the sample as it was subjected to prescribed temperature alterations. The relation between the signal and the turbidity (j) is given by the following empirical relationship [26] j (cm À1 ) = 9.0 Â 10 À9 S 3.751 . The temperature at which the first deviation of the scattered intensity from the baseline occurred was taken as the cloud point (CP) of the considered sample [19].…”

“…registered, and the average values of these runs were reported. The sample cell used was a dip-cell, including palladium electrodes with 2 mm spacing, one 12 mm glass cell PCS1115 cuvette, and a cap [26].…”