Which of the following physical forces during cell adhesion is an attractive force?

In the context of cell adhesion, attractive forces are critical because they facilitate the binding of cells to each other and to the extracellular matrix. Van der Waals forces, which are the option indicated as correct, are indeed attractive forces that arise from transient changes in electron density within molecules. These weak interactions occur between all atoms and can contribute significantly to the overall adhesion of cells, especially when many such forces act in concert across large surface areas.

Van der Waals forces help maintain close proximity between cells and between cells and substrates, thereby promoting effective adhesion, which is vital for tissue engineering applications. When cells adhere to surfaces or to each other, the collective effect of numerous van der Waals forces can create a stable attachment that is essential for tissue formation and integrity.

On the other hand, while electrostatic forces can also produce attractive interactions, their contribution depends on the charge of the interacting molecules, and they may also lead to repulsive forces under certain conditions. Steric stabilization involves the prevention of aggregations, often through repulsive forces, due to the presence of steric hindrance from large molecules. Hydrogen bonding, although a strong interaction, can also be context-dependent, leading to both attractive and repulsive interactions based on the molecular arrangement and environment.