Study On Microfluidics-Based Receptor-Ligand Binding Assay And The Modeling Simulation

In the process of biocatalytic conversion,the chemotaxis of macromolecules depends on their diffusion.Although its observations have been characterized in several different systems,the exact source of molecular chemotaxis is still unknown.This paper uses the research of this phenomenon in the field of small molecules based on microfluidic technology,and develops a new method based on the affinity analysis of molecular chemotaxis shift.By constructing a chemical concentration gradient in the microfluidic channel,the spontaneous directional migration of porphyrin molecules as receptors toward nitrogen-containing ligands is observed,and the measured receptors shift is correlated with ligands concentration,coordination number and other reaction parameters,so as to extract the dissociation constant of the intermolecular interaction.This paper also deduces a statistical thermodynamic model based on the conclusion of molecular chemotaxis shift affinity,which correlates the bound Gibbs free energy change(ΔG)with the molecular directional migration motion,to describe this intermolecular interaction process.On this basis,a self-iterative simulation calculation program is established to predict the interaction between the porphyrin receptor and the imidazole ligand and the computer simulation results are consistent with the actual experimental data.Different from the binding force measurement in the traditional homogeneous system,the flowing multiphase diffusion system can more accurately describe the spatiotemporal local characteristics of the microscopic molecular reaction,and it is also closer to the ideal statistical thermodynamic model,so it is more effective.The established model is suitable for combined analysis of multiple receptor/ligand pairs,such as enzyme activity identification,antibody sorting,small molecule drug screening,etc.In addition,by synthesizing porphyrin supramolecular Zn TCPP-TOA as the receptor,using N-containing molecules such as pyridine and di-n-octylamine as ligands,the depolymerization and diffusion of N-containing molecules on aggregates at different molecular scales were explored.The relationship between the K_D values of different ligands is:pyridine>di-n-octylamine>trioctylamine,which is negatively correlated with the size of the ligand.It reveals the different degrees of depolymerization and diffusion of Zn TCPP-TOA molecules on the spatial scale.Finally,integrate it into the simulated receptor-ligand interaction model and compare it with the experimental rules to further verify the completeness and comprehensiveness of the algorithm.