Biological potency of microsphere encapsulated plasmid DNA

Area of Science:

• Biotechnology
• Drug Delivery Systems
• Molecular Biology

Background:

• Poly(lactic-co-glycolic acid) (PLGA) microspheres are widely used for DNA delivery.
• Monitoring the biological potency of encapsulated DNA is crucial for ensuring therapeutic efficacy.
• Structural integrity of plasmid DNA can be affected during microencapsulation and storage.

Purpose of the Study:

• To evaluate the utility of three in vitro assays for monitoring the biological potency of PLGA-encapsulated DNA.
• To determine the influence of DNA structural isomers on assay results.
• To identify the most reliable method for assessing DNA potency in PLGA microspheres over time.

Main Methods:

• Comparison of three in vitro methods: mammalian cell transfection with enzyme assay, cell-free transcription/translation systems, and bacterial transformation.
• Assessment of DNA biological activity extracted from PLGA microspheres.
• Evaluation of assay sensitivity to DNA structural changes and isoforms.

Main Results:

• All three methods can assess DNA biological activity from PLGA microspheres.
• Mammalian cell transfection followed by enzyme assay provides accurate, time-dependent DNA potency determination.
• Cell-free systems and bacterial transformation show greater sensitivity to DNA isoforms and structural changes during encapsulation and storage.

Conclusions:

• Mammalian cell transfection assays offer a robust method for evaluating DNA potency in PLGA delivery systems.
• Assay selection is critical, as different methods exhibit varying sensitivities to DNA structural alterations.
• Understanding these sensitivities is key for reliable quality control of DNA-based therapeutics delivered via PLGA microspheres.