Development of an in Vitro Autocatalytic Self-Replication System for Biosensing Application

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Molecular self-replication is crucial for life but challenging to engineer in vitro.
• Existing biosensing applications for self-replication systems are limited.
• Accurate detection of DNA repair enzymes like hOGG1 is vital for understanding disease and developing therapies.

Purpose of the Study:

• To construct the first in vitro enzymatic nucleic acid self-replication system.
• To apply this system for amplified sensing of human 8-oxoguanine DNA glycosylase (hOGG1).
• To demonstrate its utility in enzyme kinetics, inhibitor screening, and clinical diagnostics.

Main Methods:

• Developed an autocatalytic self-replication system using nucleic acid templates.
• Integrated molecular beacons (MBs) as fuel and signal generators.
• Utilized hOGG1's enzymatic activity to trigger substrate unfolding and initiate replication cascade.
• Employed cascaded recycling amplification for enhanced signal generation.

Main Results:

• Achieved a highly sensitive detection limit for hOGG1 at 4.3 × 10^-7 U/μL.
• Demonstrated a broad dynamic range spanning 5 orders of magnitude (1 × 10^-6 to 0.05 U/μL).
• Successfully detected hOGG1 activity in a single lung cancer cell.

Conclusions:

• The developed in vitro self-replication system offers a powerful new tool for hOGG1 detection.
• This strategy enables sensitive enzyme activity quantification, inhibitor screening, and potential clinical diagnosis.
• The system provides a novel approach for amplified biosensing in biomedical research.