Quantitative Evaluation of Bacteria Adherent and in Biofilm on Single-Wall Carbon Nanotube-Coated Surfaces

Table 1

Adhesion of Streptococcus mutans ATCC 25175^T and Pseudomonas aeruginosa ATCC 15692 on uncoated- and SWCNT-coated-GBs.

Bacteria	Inoculum (CFUs/mL)	Uncoated GBs^a		SWCNT-GBs
		Crystal violet (OD570)	Adherent bacteria (PE-CFUs)^b	Crystal violet (OD570)	Adherent bacteria (PE-CFUs)
S. mutans	4.2 ± 0.8 × 10^8	0.009 ± 0.001	3.0 ± 0.3 × 10^7	0.007 ± 0.001	2.5 ± 0.4 × 10^7
	4.2 ± 0.5 × 10^7	0.006 ± 0.002	1.5 ± 0.5 × 10^7	0.011 ± 0.001	2.0 ± 0.3 × 10^7
	4.0 ± 0.6 × 10^6	0.008 ± 0.001	2.0 ± 0.4 × 10^6	0.006 ± 0.002	1.8 ± 0.3 × 10^6
	3.2 ± 0.3 × 10^5	0.006 ± 0.002	1.2 ± 0.3 × 10^5	0.005 ± 0.001	1.0 ± 0.5 × 10^5
	0	0.005 ± 0.001	0^c	0.005 ± 0.002	0^c
P. aeruginosa	2.4 ± 0.3 × 10^9	0.008 ± 0.002	8.0 ± 0.9 × 10^6	0.009 ± 0.002	8.0 ± 0.6 × 10^6
	2.1 ± 0.4 × 10^7	0.006 ± 0.000	6.4 ± 0.7 × 10^5	0.010 ± 0.001	6.4 ± 0.6 × 10^5
	1.2 ± 0.7 × 10^6	0.009 ± 0.001	1.2 ± 0.5 × 10^5	0.007 ± 0.002	1.2 ± 0.2 × 10^5
	2.7 ± 0.2 × 10^5	0.007 ± 0.002	3.2 ± 0.3 × 10^4	0.006 ± 0.001	4.0 ± 0.3 × 10^4
	0	0.005 ± 0.001	0^c	0.005 ± 0.001	0^c

^auncoated-GB: uncoated glass beads; SWCNT coated-GBs: glass beads coated with single wall carbon nano tubes; ^badherent S. mutans and P. aeruginosa were counted using BTA method. The number of adherent bacteria is expressed as planktonic-equivalent CFUs (PE-CFUs; see Section 2 for details); ^cincubation of BTA was prolonged to 48 hours.