Systems and methods are disclosed herein for applying near-infrared optical energies and dosimetries to alter the bioenergetic steady-state trans-membrane and mitochondrial potentials (ΔΨ-steady) of all irradiated cells through an optical depolarization effect. This depolarization causes a concomitant decrease in the absolute value of the trans-membrane potentials ΔΨ of the irradiated mitochondrial and plasma membranes. Many cellular anabolic reactions and drug-resistance mechanisms can be rendered less functional and/or mitigated by a decrease in a membrane potential ΔΨ, the affiliated weakening of the proton motive force Δp, and the associated lowered phosphorylation potential ΔGp. Within the area of irradiation exposure, the decrease in membrane potentials ΔΨ will occur in bacterial, fungal and mammalian cells in unison. This membrane depolarization provides the ability to potentiate antimicrobial, antifungal and/or antineoplastic drugs against only targeted undesirable cells.