Tailored Levofloxacin Incorporated Extracellular Matrix Nanoparticles for Pulmonary Infections

Abstract

Cystic fibrosis produces viscous mucus in the lung that increases bacterial invasion, causing persistent infections and subsequent inflammation. Pseudomonas aeruginosa and Staphylococcus aureus are two of the most common infections in cystic fibrosis patients that are resistant to antibiotics. One antibiotic approved to treat these infections is levofloxacin (LVX), which functions to inhibit bacterial replication but can be further developed into tailorable particles. Nanoparticles are an emerging inhaled therapy due to enhanced targeting and delivery. The extracellular matrix (ECM) has been shown to possess pro-regenerative and non-toxic properties in vitro, making it a promising delivery agent. The combination of LVX and ECM formed into nanoparticles may overcome barriers to lung delivery to effectively treat cystic fibrosis bacterial infections. Our goal is to advance CF care by providing a combined treatment option that has the potential to address both bacterial infections and lung damage. Two hybrid formulations of a 10:1 and 1:1 ratio of LVX to ECM have shown neutral surface charges and an average size of ~525 nm and ~300 nm, respectively. The neutral charge and size of the particles may suggest their ability to attract toward and penetrate through the mucus barrier in order to target the bacteria. The NPs have also been shown to slow the drug dissolution, are non-toxic to human airway epithelial cells, and are effective in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus. LVX-ECM NPs may be an effective treatment for pulmonary CF bacterial treatments.

Keywords: cystic fibrosis; extracellular matrix; levofloxacin; mucus barrier; nanoparticles; pulmonary delivery.

Figure 1

SEM images of 10:1 LVX-ECM NPs at the nanometer and micrometer scale (A,B) and 1:1 LVX-ECM NPs (C,D). NPs collected after being electrosprayed onto an aluminized steel sheet.

Figure 2

In vitro dissolution. Release profiles of 10:1 and 1:1 LVX-ECM NPs compared to equal amounts of free LVX. Data is displayed as mean ± SD (n = 3).

Figure 3

Calu-3 metabolic activity assay determined with MTT assay after 24 h (A) and 48 h (B) of incubation with LVX-ECM NPs and their corresponding controls. Data normalized to 24 h control to show metabolic changes between time points. Data is displayed as mean ± SD (n = 3) where * indicates p < 0.05.

Figure 4

Bacterial inhibition assay measuring bacterial growth of P. aeruginosa (A) and S. aureus (B) when cultured with LVX-ECM NPs and their corresponding free LVX controls. Data is displayed as mean ± SD (n = 3) where **** indicates p < 0.0001, *** p < 0.0005 ** p < 0.001, and * indicates p < 0.05.