Conductivity, impurity profile, and cytotoxicity of solvent-extracted polyaniline

Abstract

Understanding the correlation between the preparation, purification, impurity leaching, and cytotoxicity of polyaniline is crucial for the application of this conducting polymer in biomedicine. Polyaniline hydrochloride was purified in a Soxhlet extractor by using six different solvents: methanol, 1,2-dichloroethane, acetone, ethyl acetate, hexane, or 0.2 M aqueous hydrochloric acid. The chromatographic analyses of impurities leached out of the polymer into the solvents confirmed differences in impurity profiles, which depended on the polarity of the extraction solvent. Compared with the original polymer, the conductivity of purified polyanilines increased in dependence on the amount and type of extracted impurities. The cytotoxicity of purified samples determined on the mouse embryonic fibroblast cell line NIH/3T3 using MTT assay improved as well. Methanol and 0.2 M hydrochloric acid were the most efficient solvents capable of extracting low-molecular-weight impurities, and thus reducing polyaniline cytotoxicity. The absence of cytotoxicity was observed at an extract concentration of 10%. Extraction with suitable solvents can, therefore, be a possible way of obtaining cyto-compatible polyaniline with sufficient conductivity.

Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces

“…To reveal the cyto-compatibility of tested samples, the adhesion, proliferation and migration of the mouse embryonic fibroblast NIH/3T3 cell line was investigated. The NIH/3T3 cell line is one of the most frequently used lines in material/cell interaction research and has been previously used for cytotoxicity testing of PANI [ 15 , 16 , 17 ]. Thus, the results provided by these tests can easily be compared with data published in the literature.…”

Synthesis and Characterization of Acetic Acid-Doped Polyaniline and Polyaniline–Chitosan Composite

“…Conducting-polymers like PAni are promising materials in engineering tissues due to a combination of features such as intrinsic electrical conductivity and easy preparation [14]. However, PAni, in its powdered form, is cytotoxic possibly due to the presence of low-molecular weight impurities [15]. Studies have already presented methods for preparing high-purity PAni [15].…”

“…However, PAni, in its powdered form, is cytotoxic possibly due to the presence of low-molecular weight impurities [15]. Studies have already presented methods for preparing high-purity PAni [15]. One of these is the fabrication of PAni films combined with other polymers [16].…”

Polyaniline cryogels: Biocompatibility of novel conducting macroporous material

“…It is known that polyaniline powder displays significant toxicity 14 , 19 . Cytotoxicity is mainly connected with the presence of low-molecular-weight impurities 34 . Cryogel contains of 2 wt.% of polyaniline in the matrix; thus its toxicity should be lower than in the case of polyaniline powders, which was confirmed in the current work.…”

“…A reduction in cytotoxicity was observed after purification procedures aimed at the removal of impurities found in pristine powder polymer. Whether such procedures involved reprotonation/deprotonation 14 , reprecipitation 42 or Soxhlet extraction 34 , all such purification methods pointed to residual monomers or low-molecular-weight by-products as being responsible for cytotoxicity. In standard polyaniline powder, impurities related to residual precursors used for polymerization, i.e.…”