Background

mRNA technology demonstrated remarkable success in the development of COVID-19 vaccines and has also achieved significant breakthroughs in preventive vaccines, cancer treatment, protein replacement therapy, and gene editing. Currently, approximately 70% of global mRNA projects in preclinical and clinical stages target diseases beyond COVID-19—31% focus on cancer, and 9% on other genetic and immune disorders. This shift indicates that non-vaccine applications will drive the future development of mRNA technologies.

To ensure product quality and regulatory compliance, the USP’s 3rd edition of Analytical Procedures for Quality of mRNA Vaccines and Therapeutics  and the CDE’s Guidelines for the Development of COVID-19 Preventive Vaccines (Trial)  have established standardized methods and acceptance criteria for mRNA quality assessment. Notably, both documents specify Capillary Gel Electrophoresis (CGE)  as the preferred method for evaluating plasmid supercoiling  and mRNA integrity.

Table 1. USP-Recommended Methods for Plasmid and mRNA Integrity Testing

The principle of capillary gel electrophoresis (CGE) involves a capillary filled with gel, which connects two containers filled with buffer solution, serving respectively as the inlet and outlet. A voltage is applied across the system, and a detection window connected to a detector collects and processes data; this constitutes the CGE apparatus. Under buffer-gel conditions, the phosphate groups in nucleic acid molecules dissociate and carry a negative charge. When a reverse voltage is applied, nucleic acids move from the negative electrode toward the positive electrode. Under the same electric field conditions, nucleic acid molecules of different sizes and conformations migrate at different speeds and reach the detector at different times, thus achieving separation and detection.

Product Overview

High-quality plasmid DNA is a critical starting material in the production of mRNA, AAV vectors, and cell therapies. Plasmid DNA exists in three primary conformations: Supercoiled (SC), Linear, andOpen Circular (OC). Among these, the supercoiled form is the most desirable for biomanufacturing applications. Accurate quantification of the supercoiled plasmid proportion is essential for ensuring product quality and process consistency.

Plasmid DNA Detection Kit Capillary Gel Electrophoresis Method

This kit is designed for quantifying the proportions of supercoiled, linearized, and open circular plasmid DNA. It is compatible with various capillary electrophoresis instruments and offers high reproducibility and excellent resolution.

DNA Ladder Profile

Electrophoresis Profile of Plasmid DNA