Limits...
In vitro response of retinal pigment epithelial cells exposed to chitosan materials prepared with different cross-linkers.

Lai JY, Li YT, Wang TP - Int J Mol Sci (2010)

Bottom Line: The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples.The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated.In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, 33302, Taiwan.

ABSTRACT
The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or S(N)2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

Show MeSH

Related in: MedlinePlus

ATR-FTIR spectra of various chitosan membranes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3100825&req=5

f3-ijms-11-05256: ATR-FTIR spectra of various chitosan membranes.

Mentions: Before cytocompatibility tests, both above-mentioned samples with the same cross-linking degree were studied by Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, which is a useful tool for the identification of molecular interactions in the chemically modified biomaterials [13]. In this paper, it is difficult to interpret the spectra, primarily due to the large extent of hydrogen bonding in chitosan. Therefore, representative spectra for various membranes in the wavenumber range of 1900–1100 cm−1 are shown in Figure 3. For Chi groups, the samples had several absorption bands at 1641 cm−1 (C=O stretching in amide I), 1550 cm−1 (N-H bending in amide II), 1585 cm−1 (N-H bending in non-acetylated 2-aminoglucose primary amine), and 1151 cm−1 (C-O-C asymmetric stretching), which are characteristic of chitosan polysaccharide structure [27]. After GP cross-linking, the membranes revealed additional peaks at 1295, 1440, and 1630 cm−1, which were assigned to the C-O-C asymmetric stretching and the CH3 bending of the methyl ester, and C=C ring stretching, respectively. These data are in agreement with previous FTIR study on GP treated biopolymers [28]. The spectra of the GTA-chi groups exhibited absorption at 1652 cm−1, indicating the presence of C=N bonds from the Schiff bases. Furthermore, a new peak appeared at 1729 cm−1 which, according to the literature [29], corresponded to the carbonyl groups in the Michael-type adducts.


In vitro response of retinal pigment epithelial cells exposed to chitosan materials prepared with different cross-linkers.

Lai JY, Li YT, Wang TP - Int J Mol Sci (2010)

ATR-FTIR spectra of various chitosan membranes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3100825&req=5

f3-ijms-11-05256: ATR-FTIR spectra of various chitosan membranes.
Mentions: Before cytocompatibility tests, both above-mentioned samples with the same cross-linking degree were studied by Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, which is a useful tool for the identification of molecular interactions in the chemically modified biomaterials [13]. In this paper, it is difficult to interpret the spectra, primarily due to the large extent of hydrogen bonding in chitosan. Therefore, representative spectra for various membranes in the wavenumber range of 1900–1100 cm−1 are shown in Figure 3. For Chi groups, the samples had several absorption bands at 1641 cm−1 (C=O stretching in amide I), 1550 cm−1 (N-H bending in amide II), 1585 cm−1 (N-H bending in non-acetylated 2-aminoglucose primary amine), and 1151 cm−1 (C-O-C asymmetric stretching), which are characteristic of chitosan polysaccharide structure [27]. After GP cross-linking, the membranes revealed additional peaks at 1295, 1440, and 1630 cm−1, which were assigned to the C-O-C asymmetric stretching and the CH3 bending of the methyl ester, and C=C ring stretching, respectively. These data are in agreement with previous FTIR study on GP treated biopolymers [28]. The spectra of the GTA-chi groups exhibited absorption at 1652 cm−1, indicating the presence of C=N bonds from the Schiff bases. Furthermore, a new peak appeared at 1729 cm−1 which, according to the literature [29], corresponded to the carbonyl groups in the Michael-type adducts.

Bottom Line: The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples.The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated.In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, 33302, Taiwan.

ABSTRACT
The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or S(N)2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

Show MeSH
Related in: MedlinePlus