ABSTRACT
This study examined the effect of P85 (a pluronic block copolymer) and microbubble (MB) ultrasound contrast agents under ultrasound irradiation on gene transfection and expression. The pEGFP plasmids that can encode enhanced green fluorescent protein (pEGFP) served as a report gene and were mixed with different concentrations of MB/0.05% (w/v) P85. Then the plasmids were transfected into human hepatoma G2 (HepG2) cells. The HepG2 cells treated with MB/P85 or without treatment were exposed to ultrasound (US parameters: 1 MHz, 1.0 W/cm(2), 20 s, 20% duty cycle). Twenty-four hours later, the transfection efficiency was assessed by fluorescence microscopy and fluorescence activated cell sorting (FACS) analysis. The cell viability was evaluated by Trypan blue exclusion test. The results showed that the gene transfection efficiency in HepG2 cells under ultrasound irradiation was significantly higher than that without ultrasound irradiation. HepG2 cells in the MB or P85 group in the absence of ultrasound expressed less amount of green fluorescent protein. The expression efficiency reached (22.14±3.06)% and the survival rate was as high as (55.73±3.32)% in the 30% MB plus P85 group. It was concluded that MB and P85 in the presence of ultrasound can enhance gene transfection and expression.
ABSTRACT
Objective To investigate the relationship of gene transfection efficiency with different ultrasound exposure time and different dose of microhuhble,and to find the appropriate ultrasound parameters for gene transfection. Methods Plasmid encoding enhanced green fluorescent protein(pEGFP) was chosen as a report gene and HepG2 cells were chosen as research object. The HepG2 cells plus pEGFP and different dose of microbubble were exposed to ultrasound(1 MHz,0.5 W/cm2) with varying time. Twenty-four hours later, the expression of EGFP in the cells was observed by fluorescence microscope,the transfection efficiency was assessed by FACS and the cell viability was observed by trypan blue exclusion. Results The expression of EGFP in all experimental groups was different,and the approving transfection efficiency was got by ultrasound exposed for 20 s when the dose of microbubble was 60 μl. Conclusions With fixed ultrasound frequency and power, different transfection efficiency was got when the exposure time and dose of microbubble were different. The appropriate parameter was 20 s,60 μl, which can supply information for further study.
ABSTRACT
Ultrasonography is a simple and reliable non-invasive method in tumor vascularity detection of breast neoplasms. Tumor vascularity morphometric and topological characteristic in breast neoplasms provides an important basis for differentiation between benign and malignant lesions. Studies indicate that visual blood vessel shape and direction, velocity, properties of blood flow can be satisfactorily shown by color Doppler flow imaging(CDFI). But CDFI is confined by the angle between acoustic beam and blood flow. Power Doppler ultrasound (PDU) can overcome the difficulties mentioned above, but can not offer the information of blood velocities and motion error. The intratumoral flow features can clearly and visually shown by three-dimensional ultrasonography (3DUS) and contrast- enhanced ultrasound (CEUS). 3 DUS and CEUS will be new potential diagnosis techniques in vascularity estimation of breast neoplasms.