Immunoassays and nucleic acid detection with a biosensor based on surface plasmon resonance

Area of Science:

• Biophysical Chemistry
• Analytical Chemistry
• Biotechnology

Background:

• Label-free detection methods are crucial for real-time analysis of molecular interactions.
• Surface plasmon resonance (SPR) offers a sensitive platform for studying binding events.
• Current methods may require sample labeling or lack kinetic information.

Purpose of the Study:

• To describe a novel surface plasmon resonance (SPR) technique for detecting molecular binding.
• To demonstrate the application of this SPR method for various molecular pairs, including protein-antibody, hapten-antibody, and DNA-DNA.
• To detail the instrumentation and assess the sensitivity and speed of the developed assay.

Main Methods:

• Utilized surface plasmon resonance (SPR) to monitor changes in refractive index.
• Immobilized one binding partner onto a silver surface for detection.
• Analyzed molecular binding pairs such as protein-antibody, hapten-antibody, and DNA-DNA.

Main Results:

• Achieved rapid immunoassay for proteins and haptens in under one minute with 10(-9) mol/l sensitivity.
• Detected 10 fmoles of a 97-base DNA target sequence hybridizing to an immobilized probe in under five minutes.
• Demonstrated real-time recording of binding reaction kinetics without the need for labels.

Conclusions:

• The developed SPR technique provides a sensitive, rapid, and label-free method for molecular interaction analysis.
• The assay is versatile, applicable to various biomolecular binding events, including immunoassays and DNA hybridization.
• Further methods for enhancing assay sensitivity are discussed, highlighting the potential of this SPR approach.