A quantitative method to discriminate between non-specific and specific lectin-glycan interactions on...

Area of Science:

• Carbohydrate chemistry
• Surface science
• Biotechnology

Background:

• Carbohydrate biochip technology relies on specific protein interactions.
• Low-affinity interactions, like those with lectins, are challenging to study due to nonspecific adsorption.
• Reliable and reproducible results require interfaces free from unwanted protein binding.

Purpose of the Study:

• To fabricate glycan monolayers on silicon surfaces for carbohydrate biochips.
• To develop an efficient conjugation protocol for controlled glycan density.
• To investigate and suppress nonspecific protein adsorption on glycan-terminated surfaces.

Main Methods:

• Fabrication of mannoside and lactoside monolayers on hydrogenated crystalline silicon (111).
• Utilized a "click"-based coupling strategy for efficient conjugation.
• Probed protein adsorption using quantitative IR-ATR and atomic force microscopy (AFM).
• Analyzed adsorption data with isothermal models.

Main Results:

• Developed interfaces with controlled glycan density.
• Identified physisorption as the dominant protein adsorption mechanism under standard washing protocols.
• Demonstrated that a strong surfactinated rinse significantly suppresses physisorption.
• Confirmed coexistence of chemisorption and physisorption through surface quantification and AFM.

Conclusions:

• Nonspecific protein adsorption on glycan-terminated surfaces can be eliminated.
• Effective elimination requires precise control over surface monolayer chemistry.
• Implementation of appropriate surface-rinse protocols is essential for biochip reliability.