Abstract: The present disclosure provides improved methods and systems for transfecting host cells with nucleic acids, such as plasmid DNA, for purposes of efficiently producing biological products, such as AAV vectors, at large scale.

Abstract: A system and method is provided that includes a method for controlling an ultrasound detector system for localizing a marker seed at least partially composed of a piezoelectric material. The method includes arranging least one marker seed including a piezoelectric material proximate to a region of interest (ROI) in a subject. The method also includes arranging a detector probe including an ultrasound transducer to direct ultrasound pulses into the subject, detect return signals generated by the marker seed in response to receiving the ultrasound pulses, and generate localization data based on the return signals detected. The method further includes utilizing a display communicating a location of the marker seed based on the localization data to locate the marker seed and perform a medical procedure on the ROI in the subject.