Electrochemical DNA sensor based on methylene blue functionalized polythiophene as a hybridization indicator

Area of Science:

• Electrochemistry
• Biotechnology
• Materials Science

Background:

• Oligonucleotide detection is crucial for diagnostics.
• Methylene blue (MB) is a known electrochemical indicator.
• Existing indicators face challenges with buffer concentration variability.

Purpose of the Study:

• To synthesize and evaluate a polythiophene functionalized with methylene blue (PMT-MB) as an electrochemical indicator for oligonucleotide hybridization.
• To compare the performance of PMT-MB with methylene blue (MB) in detecting complementary oligonucleotide targets.
• To investigate the stability and reliability of PMT-MB under different buffer conditions.

Main Methods:

• Synthesis of polythiophene functionalized with methylene blue (PMT-MB).
• Electrochemical detection of oligonucleotide (ODN) hybridization using PMT-MB as an indicator.
• Comparative analysis of PMT-MB and MB performance across various buffer concentrations.
• UV-vis spectroscopy to study the interaction between PMT-MB and double-stranded ODNs (dsODNs).

Main Results:

• PMT-MB demonstrated effective recognition of complementary ODN targets, indicated by an increased current signal upon hybridization.
• PMT-MB exhibited superior resistance to buffer concentration changes compared to MB.
• Consistent current signal increases were observed with PMT-MB across all tested buffer solutions due to electrostatic interactions.
• MB showed inconsistent current responses, with signal decreases at high buffer concentrations and increases at low concentrations.

Conclusions:

• PMT-MB serves as a robust and reliable indicator for electrochemical oligonucleotide hybridization detection.
• The enhanced stability and consistent performance of PMT-MB make it a promising alternative to MB for biosensing applications.
• Electrostatic interactions play a key role in the sensing mechanism of PMT-MB.