Do quantum effects hold together DNA condensates?

The classical electrostatic interaction between DNA molecules in water in the presence of counterions is reconsidered and we propose it is governed by a modified Poisson-Boltzmann equation. Quantum fluctuations are then studied and shown to lead to a vacuum interaction that is numerically computed for several configurations of many DNA strands and found to be strongly many-body. This Casimir vacuum interaction can be the ``glue'' holding together DNA molecules into aggregates.