Antibacterial potency of different deposition methods of silver and copper containing diamond-like carbon coated polyethylene

Table 1 Physical parameters of DLC conversion and antibacterial effect of different surfaces compared to untreated PE

	DLC-processing (implantation energy, fluence)	Surface adhesion [CFU; mean +/− SD]	Bacterial growth of Ag-DLC-PE [log-levels ^a/ %]^b	p-values	Planktonic growth [CFU/ml; mean +/− SD]	Bacterial growth of Ag-DLC-PE [log-levels^a / %]^b	p-values
Comparison of antibacterial ions deposited with II: Ag vs. Cu	II (Ag): 60 keV, 1x10¹⁷ cm⁻²	2.6x10³+/− 2.5x10³	−0.8 / - 85.6 %	<.05*	1.7x10⁵+/− 8.5x10⁴	+0.05 / +13.3 %	>.05*	1st Group
	II (Cu): 55 keV, 1x10¹⁷ cm⁻²	9.0x10³+/− 2.6x10³	−0.3 / -50.0 %	<.05*	1,6x10⁵+/− 9.5x10⁴	+0.03 /+6.6 %	>.05*	1st Group
	II (Ag) vs. II (Cu)			<.05			>.05	1st Group
	Untreated PE	1.8x10⁴+/− 9.4x10³			1.5x10⁵+/− 2.8x10⁴			1st Group
Comparison of deposition methods: PIII vs. II	PIII (Ag): 5 kV, 1x10¹⁷ cm⁻²	2,5x10² +/− 1.5x10²	−2.2 / -99.1 %	<.05*	1,1x10⁴+/− 2.5x10³	−1.1 / - 96.3 %	<.05*	2nd Group
	II (Ag): 10 keV, 1x10¹⁷ cm⁻²	2,3x10³+/− 3.5x10²	−1.2 / -92.0 %	<.05*	3,6x10⁴+/− 1.2x10³	−0.6 / - 88.0 %	<.05*	2nd Group
	PIII (Ag) vs. II (Ag)			<.05			<.05	2nd Group
	Untreated PE	2.9x10⁴ +/− 2.0x10⁴			3.0x10⁵+/− 6.5x10⁴			2nd Group

^alog-levels = bacterial counts calculated as shown in following equation: log-levels = log₁₀(CFU of Ag-DLC-PE) – log₁₀(CFU of untreated PE)
^bpositive values (log-levels/%) express increased bacterial growth on Ag-DLC-PE compared to PE, negative values express reduced bacterial growth on Ag-DLC-PE compared to PE fluence = amount of ions received by a surface per unit area [ions/cm²]
* = compared to untreated PE
PIII (Ag) plasma immersion ion implantation of Ag-ions
II (Ag/Cu) conventional ion-implantation with Ag- or Cu-ions
CFU colony forming units
SD standard deviation

ISSN: 2055-7124