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Cat. No.: PRDDK-50 (for 50T)

Cat. No.: PRDDK-200 (for 200T)

Description

Plasmid Residual DNA Detection Kit (qPCR) is a probe‑based quantitative PCR (qPCR) assay designed for rapid, efficient, highly sensitive, and highly specific quantification of residual plasmid DNA in various biological product samples. This kit incorporates an anti‑contamination system containing high‑quality UDG enzyme and dUTP at optimized ratios, effectively eliminating false‑positive results or abnormally low Ct values caused by carryover contamination from previous PCR amplifications.

Plasmids are autonomously replicating, closed circular double‑stranded DNA molecules capable of expressing the genetic information they carry, and they play a central role in genetic engineering. Plasmids are widely used for target protein expression in cells, viral packaging, recombinant protein production, and the preparation of molecular vaccines or gene therapy vectors, making them one of the core tools in biotechnology. Biological products manufactured using plasmid vectors may still contain trace amounts of plasmid‑derived DNA fragments even after rigorous purification. These residual DNA fragments may pose biosafety risks, and elevated levels have been associated with increased risks of inflammation, oncogenicity, and immune dysregulation. Regulatory agencies in many countries and regions impose strict limits on host cell DNA residues in biopharmaceutical products. Monitoring and controlling DNA residues is essential for evaluating immunogenicity risk and ensuring product safety.

This kit enables highly sensitive detection of residual DNA from most plasmids, with a limit of detection as low as 40 copies/μl, approximately 0.2 fg/μl. The assay targets highly conserved regions within the replication origin (Ori) shared across widely used plasmid types, enabling quantitative detection of plasmid DNA residues in samples such as lentivirus, adenovirus, recombinant proteins, and vaccines.

This kit is based on the quantitative PCR method for exogenous DNA residue testing and employs probe‑based qPCR. The detection limit is 40–200 copies/μl. The quantitative range is 2×10² to 2×10⁶ copies/μl for non‑linearized plasmid DNA and 4×10¹ to 4×10⁶ copies/μl for linearized plasmid DNA.

Components

• Probe qPCR Mix (2X, UDG)
• Primer/Probe Mix (10X)
• Ultrapure Water
• Dilution Buffer
• Non‑linearized Plasmid DNA Control (2×10⁸ copies/μl)
• Linearized Plasmid DNA Control (4×10⁸ copies/μl)
• Low ROX (50X)
• High ROX (50X)

Features

• This kit exhibits high specificity, and genomic DNA from CHO, Vero, HEK293, and HeLa cells, as well as E. coli genomic DNA, does not interfere with plasmid DNA residue detection. The assay exclusively detects plasmid DNA and shows no cross‑reactivity with DNA from other species.
• This kit demonstrates excellent repeatability. When non‑linearized plasmid DNA at 2×10⁴ or 2×10³ copies/μl was tested in 10 replicates, the coefficient of variation (CV) for both concentrations was less than 5%.
• This kit provides the essential components required for qPCR, including the Probe qPCR Mix (2X, UDG) and a premixed set of specific primers and probe. The premix contains high‑quality, plasmid‑DNA–free Taq DNA polymerase and UDG enzyme, PCR buffer, dNTPs, dUTP, stabilizers, and magnesium ions, covering all universal reaction components. The high‑purity primer–probe mixture is designed against highly conserved regions within the replication origins (Ori) of various plasmid types, enabling ultra‑sensitive quantitative detection of plasmid DNA. In addition, the kit includes both non‑linearized and linearized plasmid DNA Controls, which serve as positive controls to verify kit performance and to generate standard curves.
• This product is available in both Low ROX and High ROX formats, ensuring broad compatibility with real‑time PCR instruments that require no ROX, Low ROX, or High ROX as a passive reference dye. ROX functions as an internal fluorescence normalization dye to correct for non‑PCR‑related signal fluctuations, thereby minimizing well‑to‑well variation. Such variation may arise from factors including pipetting errors or sample evaporation. Different qPCR instruments have different ROX requirements; therefore, users should select the appropriate Probe qPCR Mix (2X) containing High ROX, Low ROX, or no ROX based on the instrument in use. In general, Probe qPCR Mix (2X, High ROX) is also compatible with instruments that require Low ROX or no ROX.