In this contribution, the hydrothermal and irreversibility attributes of a biological nanofluid in a new heat sink enhanced with flow distributor are investigated. By increasing either concentration or velocity, the surface temperature reduces, and the cooling uniformity improves. The velocity has a more significant effect on the temperature in comparison with the effect of concentration. Increasing the velocity and concentration decreases the thermal entropy generation. Moreover, frictional entropy generation intensifies with the increment of concentration and velocity. Besides, the friction has a minor contribution in overall irreversibility of the heat sink compared with heat transfer. In the heat sink, a lower fraction of total entropy is generated in the solid walls, and chief fraction occurs in the fluid. Finally, a decision-making based approach is used for optimization in addition to the three-objective optimization. The optimization is carried out on the models obtained from the neural network to reach minimum values for the surface temperature, pumping power and irreversibility. The optimal cases are reported considering different priorities of the objective functions. The results of optimization reveal that the nanofluid employed shows the promising views to be applied in electronics cooling based on both first and second laws of thermodynamics. (C) 2018 Elsevier B.V. All rights reserved.