DNA-based molecular recognition system for lactoferrin biosensing

Area of Science:

• Biotechnology
• Molecular Biology
• Analytical Chemistry

Background:

• Lactoferrin (Lf) is an important glycoprotein with immunomodulatory functions.
• Developing selective and sensitive bioreceptors for Lf detection is crucial for diagnostics and research.
• Oligonucleotide-based aptamers offer potential as recognition elements in biosensors.

Purpose of the Study:

• To design and characterize a novel DNA oligonucleotide-based affinity bioreceptor for lactoferrin.
• To investigate the binding kinetics, affinity, and thermodynamics of the DNA-lactoferrin interaction.
• To evaluate the selectivity and sensitivity of the developed DNA bioreceptor for Lf determination.

Main Methods:

• Surface Plasmon Resonance (SPR) was used to screen and select high-affinity DNA sequences.
• Kinetic and thermodynamic analyses were performed to quantify the binding parameters.
• Electrochemical Impedance Spectroscopy (EIS) was employed to confirm the interaction and assess sensor performance.
• Selectivity was tested against potential interfering substances.

Main Results:

• A 72 base pair DNA sequence, 5'[(TAGAGGATCAAA)AAA]4TAGAGGATCAAA3', exhibited the highest affinity for lactoferrin.
• The DNA-lactoferrin interaction showed a dissociation constant (KD) of (7.61 ± 0.18) × 10⁻⁸ M.
• The complex formation was found to be endothermic and entropically driven.
• The DNA bioreceptor demonstrated high selectivity for lactoferrin, with interferents causing <3% response.
• A Limit of Detection (LOD) of 4.42 × 10⁻⁹ M was achieved for Lf determination using SPR.

Conclusions:

• A novel DNA oligonucleotide has been successfully developed as an affinity bioreceptor for lactoferrin.
• The DNA-based bioreceptor exhibits excellent affinity, selectivity, and sensitivity for lactoferrin detection.
• The developed system provides a foundation for label-free quantitative assays of lactoferrin using biosensor technologies.