High-performance immunolatex possessing a mixed-PEG/antibody coimmobilized surface: highly sensitive ferritin...

Area of Science:

• Biotechnology and Biomedical Engineering
• Materials Science and Nanotechnology
• Immunochemistry

Background:

• Development of high-performance immunoassay systems is crucial for sensitive and reliable diagnostics.
• Surface modification of nanoparticles is a key strategy to improve the efficacy of immunoassay components.
• Traditional blocking agents like bovine serum albumin (BSA) have limitations in optimizing immunoassay performance.

Purpose of the Study:

• To develop a novel blocking agent, pentaethylenehexamine-ended poly(ethylene glycol) (N6-PEG), for nanosphere surface modification.
• To covalently conjugate antiferritin antibodies and N6-PEG onto nanospheres for immunoassay applications.
• To evaluate the performance enhancement of the nanosphere/antibody/N6-PEG complex compared to BSA-blocked systems.

Main Methods:

• Synthesis and characterization of N6-PEG (N6-PEG-5k and N6-PEG-2k) and its covalent bonding onto nanospheres.
• Quantification of conjugated antiferritin and N6-PEG using the Micro BCA method.
• Characterization of the nanosphere/antiferritin/N6-PEG complex using Dynamic Light Scattering (DLS) and electrophoretic mobility (μe).
• Measurement of immune response using turbidimetric monitoring in phosphate buffer and fetal bovine serum (FBS).

Main Results:

• Optimum conditions for preparing the nanosphere/antiferritin/N6-PEG complex were determined.
• Surface modification with N6-PEG, particularly a mixture of N6-PEG-5k and N6-PEG-2k, significantly improved immunoassay performance.
• N6-PEG modification led to increased immune response yield and a decreased detection limit compared to BSA blocking.
• Enhanced performance was observed in both phosphate buffer and 100% FBS, indicating broad applicability.

Conclusions:

• N6-PEG is a highly effective novel blocking agent for nanosphere surface modification in immunoassays.
• The nanosphere/antibody/mixed-PEG complex demonstrates remarkable potential for high-performance immunoassay systems.
• This approach offers significant advantages over conventional blocking agents, paving the way for improved diagnostic tools.