Antibody Immobilization on Sulfated Cellulose Nanocrystals

Area of Science:

• Biomaterials Science
• Nanotechnology
• Immunosensors

Background:

• Cellulose nanocrystals (CNCs) offer potential for immunological biosensors due to their high aspect ratio and modifiable surfaces.
• Challenges include limited research on sulfated CNCs for antibody immobilization and poor hydrolytic stability of dried CNC assemblies.
• Existing methods struggle to achieve both robust antibody attachment and long-term stability in CNC-based biosensing platforms.

Purpose of the Study:

• To develop a versatile reaction scheme for stable antibody immobilization onto sulfated cellulose nanocrystals (CNCs).
• To enhance the hydrolytic stability of dried CNC assemblies for improved biosensor performance.
• To demonstrate the utility of modified CNCs for detecting cancer biomarkers.

Main Methods:

• Utilized 3-aminopropyl-triethoxysilane and glutaric anhydride chemistry for CNC surface modification and antibody conjugation.
• Employed Thermogravimetric Analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) to confirm CNC modification.
• Applied Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to track immobilization steps and antigen-antibody binding.

Main Results:

• Successfully demonstrated antibody immobilization onto CNCs using the developed chemistry.
• Confirmed CNC modification through TGA and FTIR analyses.
• QCM-D validated successful antibody immobilization and subsequent binding of cancer biomarker antigens (AFP, PSA, CEA).
• Both aqueous CNC dispersions and CNC films were successfully modified, with dispersed CNCs showing higher antigen-binding capacity.

Conclusions:

• The reported reaction scheme effectively enables stable antibody immobilization and enhances hydrolytic stability of CNCs.
• Modified CNCs show promise as a platform for developing sensitive and stable immunological biosensors for cancer biomarker detection.
• The method is adaptable for both dispersed CNCs and CNC films, offering flexibility in biosensor fabrication.