A method of delivering biomolecular cargo (40, 44) into cells or enveloped viruses, comprising: providing a microfluidic device comprising: a microfluidic substrate having one or more microfluidics channels disposed therein; a piezoelectric substrate (30, 46) disposed on the microfluidic substrate and having one or more pairs of interdigitated transducers (IDTs) (48, 50) disposed on opposing sides of the one or more microfluidic channels; and a signal generator coupled to the one or more pairs of IDTs (48, 50) and configured to apply an AC voltage, wherein the microfluidic device has one or more harmonic resonant frequencies; flowing a solution containing the cells or enveloped viruses through the one or more microfluidic channels, wherein the biomolecular cargo is co-flowed with the solution of cells or enveloped viruses or contained in plasmids that are disposed along inner surfaces of the one or more microfluidic channels; and powering the piezoelectric substrate (30, 46) with the signal generator at one of the harmonic resonant frequencies while the solution containing the cells or enveloped viruses passes through the one or more microfluidic channels adjacent to the piezoelectric substrate (30, 46), wherein bulk acoustic waves are generated in the one or more microfluidic channels temporarily induce pores in the cells or enveloped viruses that allow passage of the biomolecular cargo (40, 44) into the cells or enveloped viruses. providing a microfluidic device comprising: a microfluidic substrate having one or more microfluidics channels disposed therein; a piezoelectric substrate (30, 46) disposed on the microfluidic substrate and having one or more pairs of interdigitated transducers (IDTs) (48, 50) disposed on opposing sides of the one or more microfluidic channels; and a signal generator coupled to the one or more pairs of IDTs (48, 50) and configured to apply an AC voltage, wherein the microfluidic device has one or more harmonic resonant frequencies; a microfluidic substrate having one or more microfluidics channels disposed therein; a piezoelectric substrate (30, 46) disposed on the microfluidic substrate and having one or more pairs of interdigitated transducers (IDTs) (48, 50) disposed on opposing sides of the one or more microfluidic channels; and a signal generator coupled to the one or more pairs of IDTs (48, 50) and configured to apply an AC voltage, wherein the microfluidic device has one or more harmonic resonant frequencies; flowing a solution containing the cells or enveloped viruses through the one or more microfluidic channels, wherein the biomolecular cargo is co-flowed with the solution of cells or enveloped viruses or contained in plasmids that are disposed along inner surfaces of the one or more microfluidic channels; and powering the piezoelectric substrate (30, 46) with the signal generator at one of the harmonic resonant frequencies while the solution containing the cells or enveloped viruses passes through the one or more microfluidic channels adjacent to the piezoelectric substrate (30, 46), wherein bulk acoustic waves are generated in the one or more microfluidic channels temporarily induce pores in the cells or enveloped viruses that allow passage of the biomolecular cargo (40, 44) into the cells or enveloped viruses.