1. Academic Validation
  2. Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms

Delivery of fluorophores by calcium phosphate-coated nanoliposomes and interaction with Staphylococcus aureus biofilms

  • Colloids Surf B Biointerfaces. 2016 Jun 1;142:214-222. doi: 10.1016/j.colsurfb.2016.03.003.
Ignacio Rivero Berti 1 María Laura Dell' Arciprete 2 María Laura Dittler 1 Alejandro Miñan 1 Mónica Fernández Lorenzo de Mele 1 Mónica Gonzalez 1
Affiliations

Affiliations

  • 1 Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata Argentina.
  • 2 Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata Argentina. Electronic address: mlaura@inifta.unlp.edu.ar.
Abstract

The delivery capacity and mechanical stability of calcium phosphate (CaP) coated 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) liposomes free and adsorbed on Bacterial surface was investigated introducing either acridine orange (AO) or 5,10,15,20-Tetrakis(1-methyl-4-pyridinio)porphyrin (TMP) in the aqueous core of the liposomes. The obtained nanomaterials were thoroughly characterized by electron and optical microscopy and by fluorescence techniques. Distribution of the AO and TMP molecules between the aqueous liposomes core and the outer solution was demonstrated by the band shifts and broadening of the excitation-emission matrices and the modified Stern-Volmer model for fluorescence quenching. In aqueous suspensions, c.a. 40% of AO was released to the outer solution while only a small percentage of TMP was observed to reach the outer Liposome surface. The nanoliposomes adhesion capacity and the leaking of fluorophore molecules to Staphylococcus aureus (S. aureus) biofilms were further evaluated. A close interaction between liposomes and S. aureus biofilm was evidenced by TEM and SEM imaging. Epifluorescence experiments demonstrated that CaP-coated liposomes have good biofilm staining capability after two hours incubation of the biofilms with the liposomes, thus supporting an important release of the fluorophores when in contact with the biofilm. Altogether, the obtained results strongly suggest that CaP-coated liposomes are capable of activating drug release when in presence of S. aureus biofilms and smears. The studies herein presented, indicate that CaP-coated liposomes are potential vehicles for the selective delivery of drugs to S. aureus biofilms, as is the case of the singlet oxygen photosensitizer TMP, a well known photodynamic Antibacterial agent.

Keywords

5, 10, 15, 20-Tetrakis(1-methyl-4-pyridinio)porphyrin; Acridine orange; Calcium phosphate; Nanoliposomes; Staphylococcus aureus.

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