Dextran-lipase conjugates as tools for low molecular weight ligand immobilization in microarray development.

Area of Science:

• Bioconjugation Chemistry
• Biosensor Technology
• Surface Science

Background:

• Effective array biosensor development requires precise control over surface-immobilized ligand density.
• Low molecular weight haptens pose challenges for immobilization on transducing platforms.

Purpose of the Study:

• To synthesize novel dextran-lipase conjugates for immobilizing low molecular weight haptens.
• To develop high-performance immunosensors using these conjugates on glass planar waveguides.
• To optimize surface architecture for enhanced analyte detection.

Main Methods:

• Synthesis of bacterial thermoalkalophilic lipase (Geobacillus thermocatenulatus lipase 2, BTL2) and dextran conjugates.
• Immobilization of conjugates onto hexamethyldisilazane-modified glass planar waveguides via hydrophobic interactions.
• Covalent attachment of Microcystin LR (MCLR) to the dextran-BTL2 conjugates.
• Detection using an automated array biosensor with evanescent wave excitation and fluorescence measurements.

Main Results:

• Highly ordered and homogeneous molecular architectures were achieved, confirmed by atomic force microscopy.
• Conjugates with higher molecular weight dextrans (>6000) increased surface loading capacity.
• Improved performance metrics including expanded dynamic ranges (0.09-136.56 ng L(-1)), lower limits of detection (0.007 ± 0.001 ng L(-1)), and lower IC50 values (4.4 ± 0.7 ng L(-1)) for MCLR detection.

Conclusions:

• The developed dextran-lipase conjugate approach enables high-performance biosensing platforms.
• This method offers a robust strategy for immobilizing haptens and improving analyte detection sensitivity.
• The three-dimensional surface structure contributes to enhanced dynamic ranges and lower detection limits.