Theoretical limitations for aggregation methods of analysis based on affine interactions

Aggregation methods of analysis based on affine interactions are among the most in-demand techniques in analytical practice. We have developed a simple numerical model of the aggregation process and, based thereon, have identified factors and processes that can increase the sensitivity of existing aggregation methods. The differential equations describing the system are solved using the COPASI software package. The obtained theoretical dependences demonstrate that effective aggregation occurs only in a narrow range of reagent ratios; therefore, the concentrations of the marker conjugate and receptor molecules should be individually selected to reach the target working range. Achievement of high sensitivity for aggregation analysis is mainly limited by the value of the constant of association of the analyte–receptor complex. Overcoming this limitation is possible with additional stages of signal amplification or separation of the reaction mixture.