Biomedical subjects

Ying-Zheng Zhao

Publications and source records attributed to Ying-Zheng Zhao.

3 recordsLinked to original sources

PubMed2006

Comparing transfection efficiency and safety for antisense oligodeoxyribonucleotide between phospholipids-based microbubbles and liposomes.

OBJECTIVE: To compare transfection efficiency and safety for antisense oligodeoxynucleotides (AS-ODNs) between two type of phospholipids-based vectors. METHODS: An AS-ODNs sequence HA824 combined with luciferase reporter plasmid was used. Under low intensity ultrasound (US), a breast cancer cell line SK-BR-3 was exposed to different concentration of microbubbles and liposomes. Transfection efficiency was detected by fluorescence microscopy. Cell viability was verified by propidium iodide assay. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the inhibitory effect of HA824 on HER-2 expression at mRNA level. Atomic force microscopy (AFM) scanning techniques was employed to observe the change of membrane pore size. RESULTS: AS-ODNs transfection efficiency showed an increasing tend with microbubble concentration, but not with liposome concentration. Maximum transfection efficiency with minimum cell viability was achieved under 2% microbubble concentration. Too strong sonoporation activity would enlarge membrane pores significantly and cause low cell viability. CONCLUSION: US-mediated AS-ODNs transfection enhanced by phospholipids-based microbubbles represents an effective and safe avenue.

Cell Line, Tumor↗

PubMed2005

Property and contrast-enhancement effects of lipid ultrasound contrast agent: a preliminary experimental study.

This work investigated the influence of some factors on the property in vitro of a self-made lipid ultrasound (US) contrast agent (LCA) and evaluated the relationship of acoustic pressure and enhancement effect in normal rabbit kidney parenchyma. In the in vitro studies, filling gas, solvent and concentration of LCA solution were investigated. Morphologic characteristics, concentration and mean diameter of microbubbles were considered as indices. In the in vivo studies, contrast-tuned imaging (CnTi) technique was used to investigate the enhancement effects in kidney parenchyma under nine acoustic pressure levels. Among the samples saturated with different filling gases, perfluoropropane (C(3)F(8)) resulted in the highest concentration of microbubbles and air, the lowest. Microbubbles filled with C(3)F(8) or sulfur hexafluoride (SF(6)) were quite stable and remained at a high level of concentration (above 2 x 10(9) microbubbles per mL) much longer than did air-filled microbubbles. Among the four solutions tested, 5% glucose solution and 0.9% saline solution showed higher initial concentrations and greater longevity than dextran 40 glucose solution (6%) or distilled water. The concentration of LCA solution had a positive correlation with the microbubble concentration. All microbubble samples under different test conditions remained shape-complete and no aggregation or fusion was observed. The mean diameter of microbubble samples was about 3.4 microm. Contrast intensity and longevity of CnTi enhancement in vivo showed an acoustic-pressure-dependent decrease. At 1 kPa, contrast intensity increased 224-fold (4.47/0.02) and the longevity of CnTi enhancement in the kidney parenchyma remained longer.

Air↗

PubMed2005

Preparation, characterization and in vivo observation of phospholipid-based gas-filled microbubbles containing hirudin.

The objective of this work was to prepare echogenic phospholipid-based gas-filled microbubbles (PGM) and investigate their physical characteristics, echogenicity and loading ability of hirudin under various NaCl concentrations. PGM were prepared by a sonication-lyophilization method. Hirudin was used as a model drug to evaluate the drug encapsulation efficiency of the PGM. PGM loaded with hirudin were prepared by dissolving lyophilized powder with hirudin solution. The morphology, particle size and microbubble concentration of PGM were measured. The hirudin encapsulation efficiency as a function of NaCl concentration was determined. The mean particle size and microbubble concentration of PGM were unchanged by the presence of hirudin for at least 60 min after preparation. Hirudin encapsulation quantity was proportional to the hirudin concentration until saturation occurred at high concentration, and the encapsulation efficiency had an inverse relationship. Hirudin encapsulation efficiency was affected by NaCl concentration. When NaCl concentration was increased from 10 mg mL(-1) to 20 mg mL(-1) in PGM solution, hirudin encapsulation efficiency decreased from 35.8 to 26.7%, and microbubble concentration decreased from 2.7 x 10(8) to 1.7 x 10(8) microbubbles per mL. The PGM were shown easily to be visible in in vivo rabbit liver. There was no difference in echogenicity between the loaded and unloaded bubbles. PGM prepared by the sonication-lyophilization method exhibited satisfactory physical characteristics and loading ability and are suitable for use in imaging and ultrasound-triggered delivery.

Animals↗