Disclosed herein are portable handheld devices for saliva collection for daily monitoring of salivary biomarkers of physiological conditions, the device comprising: a handheld handle comprising a saliva collector, the saliva collector comprising: a suction tip a bi-directional pump electrically configurable for pumping towards two opposite directions a saliva reservoir a valve a water reservoir, the water reservoir comprising an external filling lid a reversible fluidic connection configurable in a connected and disconnected position and a base accommodating the handheld handle, the base configurable to fluidly communicate with the handheld handle through at least the reversible fluidic connection, wherein the valve is electrically configured to allow fluid communication directly between at least two selected from: the saliva reservoir, the water reservoir, and the reversible fluidic connection, and wherein the bi-directional pump is electrically configurable to allow fluid communication directly between the suction tip and the saliva reservoir.
