High performance bactericidal glass: evaluation of the particle size and silver nitrate concentration effect in ionic exchange process

Mendes, Elton; Mendes, Erlon; Savi, G. D.; Angioletto, E.; Riella, H. G.; Fiori, M. A.

doi:10.1590/0366-69132018643702197

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Articles • Cerâmica 64 (370) • Apr-Jun 2018 • https://doi.org/10.1590/0366-69132018643702197 copy

High performance bactericidal glass: evaluation of the particle size and silver nitrate concentration effect in ionic exchange process

Vidro bactericida de alto desempenho: avaliação do efeito do tamanho de partícula e da concentração de nitrato de prata no processo de troca iônica

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Antimicrobial materials have long been used as an effective means of reducing the risks posed to humans by fungi, bacteria and other microorganisms. These materials are essential in environments where cleanliness, comfort and hygiene are the predominant concerns. This work presents preliminary results for a bactericidal vitreous material that is produced by the incorporation of a silver ionic specimen through ionic exchange reactions. Powdered glass was submitted to ionic exchange in an ionic medium containing AgNO₃ as silver ions source. Different AgNO₃ concentrations in ionic medium and different particle sizes of the glass were used in the samples development. Microbiological analysis of the samples was made by disk diffusion method in the Escherichia coli and Staphylococcus aureus bacterium species. Samples were still submitted to SEM-EDS, atomic absorption and X-ray diffraction techniques. Results showed that the bactericidal effect was dependent on AgNO₃ concentration in the ionic exchange medium, but was not dependent on the particle size of the glass.

Keywords:
ionic exchange; antimicrobial materials; oligodynamic effect; bactericidal glasses

Table I - Glass formula (wt%) according to 13.

Al₂ O₃	SiO₂	Li₂ O	Na₂ O
3.00	72.00	5.00	20.00

Table II - Silver concentration for each sample obtained by EDS.

Sample	Particle size (µm)	AgNO₃ (wt%)	Silver - Ag concentration (wt%)			〈Ag〉 (wt%)	σ(wt%)
1	9.5	2	0.93	2.05	1.99	1.7	0.6
2	9.5	10	5.79	5.71	5.09	5.5	0.4
3	51.6	2	2.90	2.64	2.28	2.6	0.3
4	51.6	10	12.78	11.24	12.24	12.1	0.8
5	28.9	6	9.21	7.34	7.85	8.1	1.0
6	28.9	6	6.85	8.80	7.02	7.6	1.1
7	28.9	6	5.51	6.18	7.91	6.5	1.2

Table III - Variance analysis (ANOVA) to EDS results for powdered glass samples developed with different particle size and silver nitrate percentage.

	SS	df	MS	F	p
*(1) Particle size (µm)	*39.2992	*1	*39.2992	*18.5651	*0.000476
*(2) AgNO₃ (wt%)	*133.7336	*1	*133.7336	*63.1762	*3.99E-07
*1 by 2	*23.5760	*1	*23.5760	*11.1374	*0.003903
Error	35.9862	17	2.1168
Total SS	232.5951	20

Table IV - Silver ion concentration for each sample obtained by atomic absorption spectroscopy.

Sample	Particle size (µm)	AgNO₃ (wt%)	Silver ion - Ag⁺ concentration (wt%)		〈Ag⁺ 〉 (wt%)	σ (wt%)
1	9.46	2.0	0.00825	0.01722	0.0127	0.0063
2	9.46	10.0	0.01979	0.02170	0.0207	0.0014
3	51.60	2.0	0.01324	0.01501	0.0141	0.0013
4	51.60	10.0	0.01641	0.01836	0.0174	0.0014
5	28.89	6.0	0.01934	0.01557	0.0175	0.0027
6	28.89	6.0	0.01677	0.01714	0.0170	0.0003
7	28.89	6.0	0.01860	0.01752	0.0181	0.0008

Table V - Variance analysis (ANOVA) to atomic absorption results for powdered glass samples developed with different particle size and silver nitrate percentage.

	SS	df	MS	F	p
(1) Particle size (µm)	0.000002	1	0.000002	0.378824	0.551983
*(2) AgNO₃ (wt%)	*0.000063	*1	*0.000063	*10.666612	*0.008488
1 by 2	0.000011	1	0.000011	1.897634	0.198390
Error	0.000059	10	0.000006
Total SS	0.000137	13

Table VI - Microbiological results for different particle size and silver nitrate percentage - Escherichia coli.

Sample	Particle size (µm)	AgNO₃ (wt%)	Bactericide area - A_bac (cm² )			〈A_bac 〉 (cm² )	σ (cm² )
1	9.46	2.0	0	0	0	0	0
2	9.46	10.0	0.503	0.503	0.503	0.503	0.000
3	51.60	2.0	0.503	0.503	0.503	0.503	0.000
4	51.60	10.0	0.848	0.848	0.848	0.848	0.000
5	28.89	6.0	0.220	0.220	0.220	0.220	0.000
6	28.89	6.0	0.353	0.353	0.353	0.353	0.000
7	28.89	6.0	0.503	0.503	0.503	0.503	0.000

Table VII - Microbiological results for different particle size and silver nitrate percentage - Staphylococcus aureus.

Sample	Particle size (µm)	AgNO₃ (wt%)	Bactericide area - A _bac (cm² )			〈A_bac 〉 (cm² )	σ (cm² )
1	9.46	2.0	0.220	0.220	0.220	0.220	0.000
2	9.46	10.0	0.668	0.668	0.848	0.728	0.104
3	51.60	2.0	0.503	0.503	0.503	0.503	0.000
4	51.60	10.0	0.848	0.848	1.045	0.914	0.113
5	28.89	6.0	0.848	0.848	0.848	0.848	0.000
6	28.89	6.0	1.045	1.045	1.045	1.045	0.000
7	28.89	6.0	1.045	1.045	0.848	0.979	0.113

Table VIII - Variance analysis (ANOVA) for microbiological results with Escherichia coli for powdered glass samples developed with different particle size and silver nitrate percentage.

	SS	df	MS	F	p
(1) Particle size (µm)	0.0749	1	0.0749	0.0033	0.9547
(2) AgNO₃ (wt%)	0.5396	1	0.5396	0.0239	0.8789
1 by 2	0.0185	1	0.0185	0.0008	0.9775
Error	383.4157	17	22.554
Total SS	384.0487	20

Table IX - Variance analysis (ANOVA) for microbiological results with Staphylococcus aureus for powdered glass samples developed with different particle size and silver nitrate percentage.

	SS	df	MS	F	P
(1) Particle size (µm)	0.1318	1	0.1318	2.6171	0.1241
*(2) AgNO₃ (wt%)	*0.6333	*1	*0.6333	*12.5762	*0.0025
1 by 2	0.0070	1	0.0070	0.1397	0.7132
Error	0.8561	17	0.0504
Total SS	1.6282	20

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[TFN1] * - significant variable.