Hypersonic Poration Effect Of Bulk Acoustic Wave Resonators And Its Applications

In the past decades,membrane-disruption methods have been proposed as an important physical approach to address a subset of functions,specifically nucleic acid delivery to the certain primary cells.However,the delivery of any cargo to any cell type is still a big challenge for intracellular delivery.Recently,numerous studies have been focusing on the precision membrane disruption at the micro and nanoscale aiming to surmount current delivery limitations.With improved precision,these physical methods can be applied to accurately control the membrane permeability of single cells and target specific sites on the cell membrane.The delivery efficiency can be brought to high throughput for diverse cells with the incorporation of microfluidics and microsystem techniques.In this thesis,hypersonic poration is introduced as a new physical method to precisely control membrane permeability for the applications of controlled release and encapsulation,and enhanced drug delivery.Bulk acoustic wave(BAW)resonators of gigahertz(GHz)frequency have been fabricated using microelectromechanical system(MEMS)technologies to generate GHz ultrasound(i.e.hypersound).The mechanism of hypersonic poration has been analyzed step by step using a variety of model systems,from giant unilamellar vesicles(GUVs)to polymer-shelled vesicles(PSVs)and cancer cells.These experiments have provided a deep insight into the formation of hypersonic nanopores from lipid or supramolecular membranes to complex cell systems.This innovative poration method has the potential to be applied for intracellular delivery and other biomedical applications.1.The theoretical analyses of acoustic-fluidic effects induced by the propagation of acoustic waves in liquid,such as acoustic pressure,acoustic streaming and acoustic radiation force,were presented.A solidly mounted resonator(SMR)of 2.5 GHz frequency was designed and fabricated to generate hypersound.The structure,working pricple,circuit design and microfabrication process were described in details.2.The giant unilamellar vesicle(GUV)is introduced as a cell model to study the effects of hypersonic poration on lipid membranes.GUVs with a diameter of 15-20 μm have been immobilized on a SLB via the biotin-streptavidin affinity pair.The deformation of GUVs induced by hypersound has been analyzed using laser scanning confocal fluorescence microscopy(CLSM),while the size of hypersonic pores has been estimated by loading fluorescent polystyrene(PS)beads with different diameters into GUVs.This study suggests the potential of hypersonic poration in applications of cell manipulation.3.A study is presented on the application of hypersound to a supramolecular system for controlled encapsulation and release.Supramolecular polymer-shelled vesicles(PSVs),either suspended in solution or immobilized on a surface,have been constructed to understand the effects of hypersonic poration and to achieve controlled loading and releasing of fluorescent dyes.The studies of hypersound from lipid vesicles to supramolecular vesicles extend the application of such physical poration effects.4.The use of hypersound to enhance the intracellular delivery of polymer-wrapped mesoporous silica nanoparticles(PMSNs)loaded with Doxorubicin(Dox)was described.The cellular uptake and distribution of Dox-loaded PMSNs have been analyzed by fluorescence measurements.The cell viability has been compared with both Dox-loaded PMSNs and free Dox molecules under the stimulation of hypersound.The mechanism of hypersound-enhanced cellular uptake has been studied further through inhibitor experiments.This study provides a better understanding of hypersonic poration on enhanced intracellular delivery.