Effects of nano-sized sodium hexametaphosphate on the viability, metabolism, matrix composition, and structure of dual-species biofilms of Streptococcus mutans and Candida albicans

Abstract

This study evaluated the effects of micrometric or nano-sized sodium hexametaphosphate (HMPnano), combined or not with fluoride (NaF, 1100 ppm), on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were treated with solutions containing the polyphosphates at 0.5% or 1.0%, with/without fluoride (F), in addition to positive and negative controls. Biofilms were analysed by colony-forming units (CFU) counting, metabolic activity, production of biomass, composition of extracellular matrix, and structure. 1% HMPnano + F led to the lowest S. mutans CFU, while C. albicans CFU counts were not affected by any solution. 1% HMPnano led to the lowest metabolic activity, except for 1% HMPnano + F. All solutions promoted reductions in biofilm biomass compared to controls. Also, 1% HMPnano + F promoted the lowest concentrations of carbohydrates in the biofilm matrix, besides substantially affecting biofilms’ structure. In conclusion, HMPnano and F promoted higher antibiofilm effects compared with its micrometric counterpart for most of the parameters assessed.

Keywords:

• Phosphates
• fluorides
• biofilms
• Streptococcus mutans
• Candida albicans
• nanotechnology

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors thank Coordination for the Improvement of Higher Education Personnel (CAPES) Finance Code 001 (scholarship); PROCAD/CAPES Finance code 88881.068437/2014-01; and National Council for Scientific and Technological Development (CNPq) Finance Code 123611/2019-9 (scholarship).