Dissipative particle dynamics (DPD) is an established method for mesoscale coarse-graining fluid simulations

and has a broad range of applications in studies of micro-and nanofluidics.The method is fully off-lattice and particle based and naturally includes thermal fluctuations.Due to the importance of surface interaction

the choice of boundary condition is essential to micro-and nanofluidic researches.No-slip boundary condition

where the fluid velocity vanishes at a fluid/solid interface

is widely accepted for macroscopic fluids.A more general boundary condition is the Navier boundary condition

which allows fluid to slip.Here we briefly reviewed the DPD method and the tunable-slip method that implements the Navier boundary condition.The applicability and reliability of the simulation methods are demonstrated using two examples:one is the study of flow over a superhydrophobic surface with striped pattern.The simulation results show good agreement with the theoretic and numerical predictions.The second example is the polymer dynamics in a microfluidic device.The modification of the boundary condition can induce different polymer dynamics under confinement.Both examples demonstrate that DPD simulations can provide guidance in the design of better and efficient micro-and nanofluidic devices.