Development of a novel fluorescence light-up Pb²⁺ sensor using a G-quadruplex complex with modified thioflavin T

Area of Science:

• Analytical Chemistry
• Biochemistry
• Environmental Science

Background:

• Lead ions (Pb²⁺) pose significant environmental and health risks.
• Accurate and sensitive detection methods for Pb²⁺ are crucial for monitoring and remediation.
• Existing biosensors often face limitations in cost-effectiveness, sensitivity, or selectivity.

Purpose of the Study:

• To develop a novel, cost-effective fluorescence light-up biosensor for the detection of lead ions (Pb²⁺).
• To optimize the biosensor by evaluating different G-quadruplex sequences and modified thioflavin T (ThT) derivatives.
• To validate the practical applicability of the developed biosensor for environmental water samples.

Main Methods:

• Utilized a label-free G-quadruplex (specifically T2 sequence) as the recognition element.
• Employed modified thioflavin T (ThT) derivatives, including ethyl-substituted ThT (ThT-E), propyl-substituted ThT (ThT-P), and butyl-substituted ThT (ThT-B).
• Measured fluorescence enhancement upon interaction of the G-quadruplex-ThT derivative complex with Pb²⁺.

Main Results:

• The T2 G-quadruplex sequence demonstrated fluorescence light-up properties in the presence of Pb²⁺ and modified ThT derivatives.
• Ethyl-substituted ThT (ThT-E) showed the most significant fluorescence enhancement, indicating optimal performance.
• The developed biosensor exhibited high selectivity and sensitivity for Pb²⁺ detection.
• Successful detection of Pb²⁺ in spiked environmental water samples confirmed the sensor's practical utility.

Conclusions:

• A novel, cost-effective fluorescence light-up biosensor for Pb²⁺ detection was successfully developed.
• The optimized sensor using the T2 G-quadruplex and ThT-E offers high sensitivity and selectivity.
• This strategy holds potential for developing versatile platforms for detecting various metal ions in environmental samples.