Fluorescent bioinspired albumin/polydopamine nanoparticles and their interactions with Escherichia coli cells

Eloïse Equy; Jordana Hirtzel; Sophie Hellé; Béatrice Heurtault; Eric Mathieu; Morgane Rabineau; Vincent Ball; Lydie Ploux

doi:10.3762/bjnano.14.100

Fluorescent bioinspired albumin/polydopamine nanoparticles and their interactions with Escherichia coli cells

Beilstein J Nanotechnol. 2023 Dec 22:14:1208-1224. doi: 10.3762/bjnano.14.100. eCollection 2023.

Authors

Eloïse Equy^#^{1

2}, Jordana Hirtzel^#^{2

3}, Sophie Hellé^{1

2}, Béatrice Heurtault³, Eric Mathieu^{1

2}, Morgane Rabineau^{1

2}, Vincent Ball^{1

2}, Lydie Ploux^{1

2

4}

Affiliations

¹ UMR_S1121, INSERM/University of Strasbourg, 1 rue Eugène Boeckel, 67084 Strasbourg, France.
² Faculty of Dentistry, University of Strasbourg, 8 Rue Ste Elisabeth, 67000 Strasbourg, France.
³ UMR 7199, CNRS/University of Strasbourg, 74 route du Rhin, 67401 Illkirch, France.
⁴ CNRS, 23 rue du Loess, 67200 Strasbourg, France.

^# Contributed equally.

Abstract

Inspired by the eumelanin aggregates in human skin, polydopamine nanoparticles (PDA NPs) are promising nanovectors for biomedical applications, especially because of their biocompatibility. We synthesized and characterized fluorescent PDA NPs of 10-25 nm diameter based on a protein containing a lysine-glutamate diad (bovine serum albumin, BSA) and determined whether they can penetrate and accumulate in bacterial cells to serve as a marker or drug nanocarrier. Three fluorescent PDA NPs were designed to allow for tracking in three different wavelength ranges by oxidizing BSA/PDA NPs (Ox-BSA/PDA NPs) or labelling with fluorescein 5-isothiocyanate (FITC-BSA/PDA NPs) or rhodamine B isothiocyanate (RhBITC-BSA/PDA NPs). FITC-BSA/PDA NPs and RhBITC-BSA/PDA NPs penetrated and accumulated in both cell wall and inner compartments of Escherichia coli (E. coli) cells. The fluorescence signals were diffuse or displayed aggregate-like patterns with both labelled NPs and free dyes. RhBITC-BSA/PDA NPs led to the most intense fluorescence in cells. Penetration and accumulation of NPs was not accompanied by a bactericidal or inhibitory effect of growth as demonstrated with the Gram-negative E. coli species and confirmed with a Gram-positive bacterial species (Staphylococcus aureus). Altogether, these results allow us to envisage the use of labelled BSA/PDA NPs to track bacteria and carry drugs in the core of bacterial cells.

Keywords: Escherichia coli; accumulation; albumin; antibacterial; fluorescence; nanoparticles; penetration; polydopamine.

Grants and funding

The authors would like to thank Region Grand Est (ERMES project), ANR (Agence Nationale de la Recherche) (project No. ANR-21-CE17-0020-0) and the “Groupement de Recherche” GDR B2I (GDR3751) for their support.