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. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Biomaterials. 2009 Oct 9;31(4):669–679. doi: 10.1016/j.biomaterials.2009.09.087

Figure 4. C. neoformans biofilms are more resistant to chitosan than planktonic cells.

Figure 4

(A) The percentage of metabolic activity of C. neoformans strain B3501 biofilms and planktonic cells was measured by the XTT reduction assay. Both phenotypes were exposed to 0.625 mg/mL of chitosan for 0.5, 1, and 2 h; and their metabolic activities were compared to those of fungal cells incubated in PBS. (B) The percent survival of C. neoformans strain B3501 biofilms and planktonic cells was measured by determination of the numbers of CFU. Both phenotypes were exposed to 0.625 mg/mL of chitosan for 0.5, 1, and 2 h; and their rates of survival were compared to those of fungal cells incubated in PBS. For panels A and B, the bars are the averages of four measurements, and brackets denote standard deviations. *, P<0.05 and **, P<0.01 in comparing biofilms and planktonic cells. This experiment was done twice, with similar results each time. (C-G) SEM of C. neoformans B3501 (C) biofilms and (D) planktonic cells treated with chitosan. C. neoformans biofilms grown in the presence of 0.625 mg/mL of chitosan showed fungal cells surrounded by large amounts of exopolymeric matrix. In contrast, planktonic cells treated with similar concentration resulted in significant decrease of capsular polysaccharide and (E-G; insets) cellular damage. White arrows denote cellular damage. Scale bar for C and D: 10 μm, and E-G: 2 μm.