Bacterial Minicell-Based Biohybrid Sub-micron Swimmers for Targeted Cargo Delivery.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Microbiology

Background:

• Bacterial biohybrid microrobots offer potential for targeted therapy but face challenges in biocompatibility and cargo loading.
• Bacterial membrane vesicles, or minicells, are promising sub-micron biohybrid components due to their active metabolism, stability, and cargo capacity.

Purpose of the Study:

• To develop and characterize novel biohybrid microrobots using motile minicells for targeted drug delivery.
• To functionalize minicells for magnetic control and assess their drug loading, release, and therapeutic efficacy.

Main Methods:

• Engineered Escherichia coli (E. coli) were used to generate motile minicells (≈400 nm).
• Minicells were purified (>99%) and functionalized with magnetic nanoparticles (MNPs) for external control.
• Drug loading capacity, motility under magnetic fields, pH-sensitive drug release, and in vitro cytotoxicity were evaluated.

Main Results:

• Minicell biohybrids achieved high purification and were effectively controlled by a magnetic field (26 mT), swimming up to 13.3 µm s⁻¹.
• High drug loading capacity (2.8 µg mL⁻¹) was observed, with pH-sensitive release of doxorubicin hydrochloride (DOX) under acidic conditions.
• Drug-loaded minicell biohybrids demonstrated significant reduction in SK-BR-3 breast cancer cell viability in vitro.

Conclusions:

• Minicell biohybrids represent a novel class of magnetically guided, drug-loaded biohybrid systems.
• This study establishes their potential for targeted therapies and future medical applications.