A biosensor may provide a magnetoresistive (MR) film comprising a nonmagnetic layer may be sandwiched between the two ferromagnetic layers. The MR film may be positioned on a substrate, where the edges of the MR film are in contact with leads. The leads may be in contact with pads. The sensors may provide quasi-digital readout that enable greatly enhanced sensitivity. In some embodiments, biosensors may be arranged as array of sensors. The array of sensors may be arranged as a symmetric or asymmetric N1×N2 array, where N1 and N2 are integers, N1 represents the number of sensors linked together in series, and N2 represents the number of sensor sets in parallel, where each sensor set may comprise one or more sensors. Further, the array of sensors may be coupled to a voltmeter, which may be a single voltmeter in that allows the sensors to all be probed simultaneously.