# Dual Core-Shell Loaded Lipid-Polymer Hybrid Nanoparticles as Combination Anti-Infective Delivery Platforms

## TL;DR

This study shows that dual-core shell nanoparticles can effectively deliver antibiotics and antimicrobial peptides to fight bacteria, especially E. coli.

## Contribution

The novelty lies in the dual loading of anti-infectives in both core and shell compartments of lipid-polymer hybrid nanoparticles.

## Key findings

- Uniformly nanosized LPHNPs were successfully produced with maximized loading of cefotaxime and RN7IN6.
- Empty LPHNPs showed antibacterial activity, particularly against Escherichia coli.
- RN7IN6 enhanced cefotaxime activity against E. coli when co-loaded in LPHNPs.

## Abstract

Background/Objectives: The growing threat posed by antimicrobial resistance to worldwide public health highlights the urgent need not only for new anti-infective candidates, but also for innovative formulation strategies capable of mediating effective delivery of anti-infective compounds. The current study, therefore, aimed to demonstrate the feasibility of formulating lipid-polymer hybrid nanoparticles (LPHNPs) with dual loading of both core and shell compartments for combination anti-infective delivery. Methods: LPHNPs containing the antibiotic cefotaxime within a chitosan polymer core and the novel antimicrobial peptide RN7IN6 within a bacteria-mimicking lipid shell were produced by microfluidic mixing, and optimized with respect to parameters including total flow rate, flow rate ratio, and lipid concentration. Minimum inhibitory concentrations of cefotaxime and RN7IN6 co-incorporated in LPHNPs were assessed as a preliminary indicator of antibacterial efficacy. Results: Uniformly nanosized LPHNPs were produced, with maximized loading of cefotaxime and RN7IN6 within particle cores and shells, respectively. Empty LPHNPs showed an appreciable antibacterial activity, particularly against the Gram-negative bacterium Escherichia coli, while RN7IN6 was indicated to enhance cefotaxime activity against E. coli when both actives were incorporated in LPHNPs. Conclusions: The current findings clearly demonstrate the feasibility of formulating LPHNPs for core-shell co-encapsulation and delivery of anti-infectives. The promising antibacterial efficacy of co-loaded LPHNPs warrants further in-depth investigation to determine the extent of co-loaded LPHNP applications as combination anti-infective delivery platforms.