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Synthesis and antimicrobial activity of some novel cross-linked chitosan hydrogels.

Mohamed NA, Fahmy MM - Int J Mol Sci (2012)

Bottom Line: Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction.The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan.Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt; E-Mail: m.fahmy17@yahoo.com.

ABSTRACT
Four novel hydrogels based on chitosan were synthesized via a cross-linking reaction of chitosan with different concentrations of oxalyl bis 4-(2,5-dioxo-2H-pyrrol- 1(5H)-yl)benzamide. Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction. The antimicrobial activities of the hydrogels against two crop-threatening pathogenic fungi namely: Aspergillus fumigatus (A. fumigatus, RCMBA 06002), and Aspergillus niger (A. niger, RCMBA 06106), and five bacterial species namely: Bacillis subtilis (B. subtilis, RCMBA 6005), Staphylococcus aureus (S. aureus, RCMBA 2004), Streptococcus pneumoniae (S. pneumonia, RCMB 000101) as Gram positive bacteria, and Salmonella typhimurium (S. typhimurium, RCMB 000104), and Escherichia coli (E. coli, RCMBA 5003) as Gram negative bacteria have been investigated. The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan. The hydrogels were more potent in case of Gram-positive bacteria than Gram-negative bacteria. Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

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Scanning electron micrographs of the hydrogels surfaces at a magnification of 400×: (a) H0.5; (b) H1; (c) H2.5; (d) H5.
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f2-ijms-13-11194: Scanning electron micrographs of the hydrogels surfaces at a magnification of 400×: (a) H0.5; (b) H1; (c) H2.5; (d) H5.

Mentions: Microstructures of the hydrogels surface were investigated by scanning electron microscopy as presented in Figure 2. It could be seen that the hydrogels have a channel-like surface with an extremely porous structure. While the hydrogels have a similar surface appearance, the distribution and the size of their pores are different. The distribution of porosity became more uniform and dense with increasing concentrations of cross-linking moieties incorporated into the gel (H5 hydrogel). On the other hand, the pore size of the hydrogels decreased with the increase of the cross-linking density of the hydrogels, e.g., from H0.5 to H5 hydrogels.


Synthesis and antimicrobial activity of some novel cross-linked chitosan hydrogels.

Mohamed NA, Fahmy MM - Int J Mol Sci (2012)

Scanning electron micrographs of the hydrogels surfaces at a magnification of 400×: (a) H0.5; (b) H1; (c) H2.5; (d) H5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472739&req=5

f2-ijms-13-11194: Scanning electron micrographs of the hydrogels surfaces at a magnification of 400×: (a) H0.5; (b) H1; (c) H2.5; (d) H5.
Mentions: Microstructures of the hydrogels surface were investigated by scanning electron microscopy as presented in Figure 2. It could be seen that the hydrogels have a channel-like surface with an extremely porous structure. While the hydrogels have a similar surface appearance, the distribution and the size of their pores are different. The distribution of porosity became more uniform and dense with increasing concentrations of cross-linking moieties incorporated into the gel (H5 hydrogel). On the other hand, the pore size of the hydrogels decreased with the increase of the cross-linking density of the hydrogels, e.g., from H0.5 to H5 hydrogels.

Bottom Line: Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction.The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan.Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt; E-Mail: m.fahmy17@yahoo.com.

ABSTRACT
Four novel hydrogels based on chitosan were synthesized via a cross-linking reaction of chitosan with different concentrations of oxalyl bis 4-(2,5-dioxo-2H-pyrrol- 1(5H)-yl)benzamide. Their structures were confirmed by fourier transform infrared X-ray (FTIR), scanning electron microscopy (SEM) and X-ray diffraction. The antimicrobial activities of the hydrogels against two crop-threatening pathogenic fungi namely: Aspergillus fumigatus (A. fumigatus, RCMBA 06002), and Aspergillus niger (A. niger, RCMBA 06106), and five bacterial species namely: Bacillis subtilis (B. subtilis, RCMBA 6005), Staphylococcus aureus (S. aureus, RCMBA 2004), Streptococcus pneumoniae (S. pneumonia, RCMB 000101) as Gram positive bacteria, and Salmonella typhimurium (S. typhimurium, RCMB 000104), and Escherichia coli (E. coli, RCMBA 5003) as Gram negative bacteria have been investigated. The prepared hydrogels showed much higher antimicrobial activities than that of the parent chitosan. The hydrogels were more potent in case of Gram-positive bacteria than Gram-negative bacteria. Increasing the degree of cross-linking in the hydrogels resulted in a weaker antimicrobial activity.

Show MeSH
Related in: MedlinePlus