Surface characterization and cytocompatibility evaluation of silanized magnesium alloy AZ91 for biomedical applications

Figures & data

Table 1. List of used silane solutions. MW stands for molecular weight.

Name of silane	Formula	MW
(S1) ethyltriethoxysilane^a	C2H5Si(OC2H5)3	192.3
(S2) 3-aminopropyltriethoxysilane^a	H2N(CH2)3Si(OC2H5)3	221.4
(S3) 3-isocyanatopropyltriethoxy silane^b	NCO(CH2)3 Si(OC2H5)3	247.37
(S4) phenyltriethoxysilane^a	C6H5Si(OC2H5)3	240.4
(S5) octadecyltriethoxy silane^a	C18H37Si(OC2H5)3	416.8

a Silicon Chemicals, Shin Etsu, Japan.

b Avocado, Research Chemicals Ltd, UK.

Figure 1 Time evolution of water contact angles of unmodified and silanized AZ91.

Table 2. Binding energies (BE, in eV) for unmodified and silanized (S1, S5) samples.

	Peak BE
AZ91 unmodified	S1	S5
Si2p	99.58	99.65	99.44
	–	102.11	101.92
C1s	285.59	285.27	285.31
O1s	532.98	532.83	532.75
	531.21	531.02	530.98
Mg2p	51.08	51.13	51.28
	49.74	49.84	50.08
Al2p	72.56	72.63	72.54
	75.04	75.09	74.93
F1s	686.55	686.52	686.48

Table 3. Chemical composition of AZ91 magnesium alloy before and after silanization (S1, S5).

Sample name	XPS concentration (at. %)
Si	C	O	Mg	Al	F
AZ91 unmodified	0.89	11.91	31.3	38.26	3.65	12.55
S1	2.74	3.26	34.54	40.31	3.9	14.69
S5	2.09	7.54	33.74	39.91	3.54	12.52

Figure 2 Amounts of albumin adsorbed onto unmodified and silanized AZ91.

Figure 3 Evaluation of cell viability by WST-1 assay after 1, 4 and 7 days of incubation on unmodified and silanized AZ91 magnesium alloy samples.

Figure 4 Cell morphology of SaOS-2 cultured on unmodified and silanized AZ91.

Figure 5 Surface density of Mg²⁺ ions released from unmodified and silanized AZ91 during cell culture.