A method includes generating, from an integrated oscillator circuit, an oscillating output signal and generating, by an integrated power amplifier (PA) circuit, an amplified oscillating output signal based on the oscillating output signal. The method further includes receiving, by integrated receiver amplifier circuit, an electron spin resonance (ESR) signal from biological samples that include a magnetic species and generating, by the integrated receiver amplifier circuit, an amplified ESR signal based on the received ESR signal. The method further includes receiving, by the integrated receiver amplifier circuit, an electron spin resonance (ESR) signal from magnetic nanoparticles that are loaded with drugs or attached to human cells.