Synthesis and Characterization of New Thiolated Chitosan Nanoparticles Obtained by Ionic Gelation Method

Reynaldo Esquivel,Miguel A Valdez,Josué Juárez,Jaime Ibarra,Mario Almada

doi:10.1155/2015/502058

Reynaldo Esquivel, Miguel A Valdez + Show 3 more

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https://doi.org/10.1155/2015/502058

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Abstract

We derivatized low molecular weight chitosan (LMWC) with 3-mercaptopropanoic acid (3-MPA) by a coupling reaction. The chemical modification of LMWC was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance,1HNMR. We researched the influence of 3-MPA on the nanoparticles formation by ionic gelation method using sodium tripolyphosphate (TPP) as cross-linker reagent. In order to optimize the nanoparticles formation, we studied the effect of the pH solution and molar ratio on nanoparticles stability. Analyses of particle size, morphology, and surface charge were determined by dynamic light scattering, Atomic Force Microscopy, and zeta potential, respectively. It was found that formation of semispherical and stable nanoparticles was improved due to the chemical modification of chitosan. Optimized semispherical nanoparticles of thiolated chitosan were synthesized with the parameters (pH 4.7, molar ratios 1 : 106). Additionally, we reported the thermodynamic profile of the nanoparticles formation determined by isothermal titration calorimetry (ITC). The aggregation process achieved to form nanoparticles of thiolated and nonmodified chitosan consisted of two stages, considering one binding site model. Gibbs free energy(ΔG)and binding constant (Ka) describe the aggregation process of thiolated chitosan/TPP, which is an initial reaction and followed by an endothermic stage. These results are promising for the possible application of these nanoparticles as nanocarriers and delivery systems.

Highlights

Nanotechnology is often used to solve problems in several areas as electronics, environment, agriculture, and biotechnology [1,2,3,4]
Results of the analysis indicate the successful modification of native chitosan selectively on the amine groups, by the reaction between the primary amine groups of chitosan and the carboxylic groups of the mercaptopropionic acid resulting in amide group
We researched the effect of chemical derivatization on native chitosan properties by coupling reaction with 3-mercaptopropionic acid; the reaction reached 11% of modification degree of free amine groups

Summary

Introduction

Nanotechnology is often used to solve problems in several areas as electronics, environment, agriculture, and biotechnology [1,2,3,4]. It is known that surface charge of the nanostructures plays an important role in adherence and cellular uptake mechanism through electrostatics interactions with cellular membranes For this reason, several research groups have developed versatile methodologies to elaborate nanostructured materials that have a potential application in medical areas as therapeutic agent, contrast agent, among others [7,8,9]. Several research groups have developed versatile methodologies to elaborate nanostructured materials that have a potential application in medical areas as therapeutic agent, contrast agent, among others [7,8,9] To achieve this goal, it is important to use biocompatible polymers, for example, polyethylene glycol (PEG) [10], chitosan [11], and poly(lactic-co-glycolic acid) (PLGA) [12]. It is a challenge to design monodisperse and stable polymeric particles useful in certain applications, including cancer therapy and gene therapy

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