DNA-based molecular recognition system for lactoferrin biosensing

The paper describes the development of a novel DNA oligonucleotide-based affinity bioreceptor that binds to lactoferrin, a glycoprotein-type immunomodulator. The research was performed using surface plasmon resonance method to investigate affinity of various types of oligonucleotides to the target protein. The 72 base pair-long 5'[(TAGAGGATCAAA)AAA](4)TAGAGGATCAAA3' sequence with the highest affinity to lactoferrin was selected for further investigations. Kinetic analysis of the interaction between selected DNA and lactoferrin provided rate and equilibrium constants: k(a) = (2.49 +/- 0.03)center dot 10(4) M-1 center dot s(-1), k(d) = (1.89 +/- 0.02)center dot 10(-3) s(-1), K-A = (0.13 +/- 0.05)center dot 10(8) M-1, and K-D = (7.61 +/- 0.18)center dot 10(-8) M. Thermodynamic study conducted to determine the Delta H-0, Delta S-0, and Delta G(0) for van't Hoff characteristic in the temperature range of 291.15-305.15 K, revealed the complex formation as endothermic and entropically driven. The chosen DNA sequence's selectivity towards lactoferrin was confirmed with interferents' response constituting <3 % of the response to lactoferrin. SPR analysis justified utility of the designed DNA oligonucleotide for Lf determination, with LOD of 4.42 center dot 10(-9) M. Finally, the interaction between lactoferrin and DNA was confirmed by electrochemical impedance spectroscopy, providing the basis for further quantitative assay of lactoferrin using the developed DNA-based bioreceptor. The interactions were performed under immobilized DNA ligand conditions, thus reflecting the sensor's surface, which facilitates their transfer to other label-free biosensor technologies.

Automated summary

The paper describes the development and utility of a novel DNA oligonucleotide-based affinity bioreceptor for lactoferrin. The research investigates the affinity of different types of oligonucleotides to the target protein using surface plasmon resonance method. The selected DNA sequence showed high affinity to lactoferrin and demonstrated its potential as a bioreceptor for lactoferrin determination.