We have invented a technique that uses precisely tuned ultrasound to measure the binding forces of molecular bonds and consequently achieve mechanical control of the interactions. In a general scheme, one of the molecules forming the bonds is immobilized, and the other is labeled with magnetic particles. Precisely tuned ultrasound is then applied to induce bond dissociation. The high tuning resolution of the ultrasound enables selective dissociation of antibodies of different subclasses and DNA duplexes with a single basepair difference. By integrating a sonicator with an atomic magnetometer, the resulting apparatus will be able to noninvasively manipulate molecular interactions based on their binding strengths. This invention is a one-of-its-kind technique for mechanical control of molecular bonds, which are widely encountered in drug targeting and biomedical molecular imaging.