Yonghong Tang

In vivo sonoluminescence imaging with the assistance of FCLA

In this paper, sonoluminescence of tissues is reported for the first time. A sonoluminescence image of a living animal was obtained with a high-sensitivity imaging system. Furthermore, to enhance biological sonoluminescence, fluoresceinyl Cypridina luminescent analogue (FCLA), a chemiluminescence analysis agent, was used in the experiment. With the assistance of FCLA we succeeded in observing an image of a living animal with high contrast and good signal-to-noise ratio. This technique has potential applications in clinical diagnosis.

Comparing ultraweak bio-chemiluminescence emission in wounded green and etiolated soybean cotyledons

Ultraweak bio-chemiluminescence (UBC) from germinating soybean (Glycine max L. Merr) cotyledon under mechanical wounding was observed by a high sensitivity imaging system based on an intensified charge couple device (ICCD) detector or a high sensitive single photon counter (SPC) device. The UBC imaging showed that the intensity of UBC at the injury location on a wounded green cotyledon was greater than on a wounded etiolated cotyledon. Based on results with a SPC UBC intensity of wounded green cotyledon was high at first and then gradually decreased. The emission spectrum of wounded green cotyledon had a greater proportion of red light. The increase in UBC of wounded etiolated soybean cotyledon was less than that of green ones. The emission spectrum of wounded etiolated cotyledon had a greater amount of orange light. The data suggest that most of the UBC in green cotyledon was due to damaged chloroplasts and mitochondria. Our data suggest that oxidation of damages tissue lead to the production of ROS. Electronic excitation energy was transfered from the excited molecules by ROS to Chl-a in the thylakoid membranes, so the intensity of UBC in the wounded soybean green cotyledon was obviously higher than in the wounded etiolated soybean cotyledon.

The study of optimal condition of SPIO labeling human lung adenocarcinoma cell line (SPC-A-1)

Propose: To study the optimal concentration and time of incubation of human lung adenocarcinoma cell line (SPC-A-1) labeled with superparamagnetic iron oxide (SPIO) particles in vitro. Methods: Human lung adenocarcinoma cell line (SPC-A-1) was cultured with different concenration of SPIO and different time of incubation (labeled with media containing Fe-PLL: 25μg /mL, 100μg /mL, and 200 μg /mL, and for 30min, 90min, 180min. The phagocytosis of the cells was observed by laser scanning confocal microscopy (LSCM) to determine particle uptake and their distribution in cells. Results: Human lung adenocarcinoma cells(SPC-A-1) have taken up a large amount of SPIO particles within the first 3h. Conclusion: In this study, the concentration of iron with 25μg/ml SPIO and time of incubation for 30min is the optimal condition for labeling the SPC-A-1 with SPIO.

Investigation of singlet oxygen generation in Vit C-Cu2+ -LDL system by chemiluminescence method

In this study, by chemiluminescence method using a Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3,7- dihydroimidazo[1,2-a]pyrazin-3-one (MCLA), as a selective and sensitive chemiluminescence probe, singlet oxygen (1O2) formation was observed in the vit C- LDL-Cu2+ reaction system. Another experimental evidence for the generation of 1O2 was the quenching effect of sodium azide (NaN3) on vit C-induced chemiluminescence in the reaction mixture of LDL- Cu2+-MCLA. Analysis based on the experimental results indicated the plausible reaction mechanism is that vit C converts Cu2+ to its reduced state and vit C becomes vit C radical itself, thereby stimulating the formation of peroxyl radicals, and bimolecular reaction of peroxyl radicals results in 1O2 production in the above systems.

Experimental research of photodynamic diagnosis mediated by chemiluminescence reagents

There are some serious limitations existing in conventional photodynamic diagnosis (PDD), such as autofluorescence disturbance, weak red-band absorption efficacy of traditional photosensitizers and quite short penetration depth of excitation light. In this paper a novel method of PDD mediated by chemiluminescence reagents is presented in fabricated mixed samples. Photodynamic therapy (PDT) is believed to act via singlet oxygen (1O2) generated by energy from photosensitizers. 5-Fluoresceinyl Cypridina Luciferin Analog (FCLA), a chemiluminescence reagent, can react with singlet oxygen and emit chemiluminescence with peak wavelength about at 526 nm. In the experiments, FCLA was chosen as an optical reporter of localization of singlet oxygen produced from photosensitized reaction of Hematoporphyrin Derivative (HpD) excited by 630 nm laser. Experimental results, the measurement of fluorescence spectra and the detection of image from chemiluminescence, show that the mixed HpD and FCLA in biologic tissue mixture excited with the laser of 630 nm can emit detectable light signals.

Sonoluminescence imaging and its biomedical applications

Sonoluminescence (SL) images of living bodies were obtained by a luminescence enhancement method with a high-sensitive back-illuminated CCD system. We found that the rare-gas- contained (prepared) PBS or some nonpoisonous chemiluminescent analytic agent could enhance the SL by chemiluminescence through a reaction with free radicals, and can be used for in vivo experiments. Based on ultrasound could sensitize HpD to produce the oxygen free radicals, a novel method for early-stage cancer diagnosis named as Sono- Dynamic Diagnosis was proposed. By use of sonosensitization to produce tumor-selective oxygen radicals, a clear diagnostic image of FCLA (Fluoresceinyl Cypridina Luminescent Analog)-enhanced sono-pumped chemiluminescence from tumor region is obtained. Finally, a confocal scanning technique was developed for the sonoluminescence tomography imaging for the first time. The spatial resolution was largely improved to about 100 micro with the ultrasonic intensity less than the safety limit of FDA. With the components-labeling and confocal techniques, the SL imaging method has potential applications in clinical diagnosis.

Enhanced sonoluminescence of tissues

In this paper, biological sonoluminescence (SL) of different tissues was investigated for the first time. Tissue samples (muscle, liver and fat) were prepared and put into a column- shaped ultrasound field. A photomultiplier tube and a back- illuminated cooled CCD were used to detect the SL signal. In the experiments, FCLA (Fluoresceinyl Cypridina Luminescent Analog) was used to enhance SL. With the chemiluminescence technique, we suggest that the biological SL mainly come from the free radicals produced by the ultrasound cavitation, which is different from the mechanism of the SL in aqueous solutions.

Novel cancer diagnostic method: FCLA-assisted sonodynamic diagnosis

In this paper, we propose, for the first time, the concept of Sono-Dynamic Diagnosis (SDD). The novel method named FCLA Assisted Sono-Dynamic Diagnosis is designed as follows: HpD is used to localize the cancer tissue, and is sonosensitized by the ultrasound field to produce singlet oxygen. Then, another reagent, FCLA (Fluoresceinyl Cypridina Luminescent Analog), reacts with O2 to efficiently transform the chemical energy of O2 to photons, thus a strong chemiluminescence is emitted. One can then detect this emission with a high sensitive CCD imaging system to localize the tumor. Based on the principle of FCLA assisted SDD, we obtained a clear diagnostic image of a transplanted tumor in a nude mouse in the experiments. It is shown that the emission from the tumor region is much stronger than that from other regions. The outline of the tumor is quite clear. This method could have potential applications in clinics for early-stage tumor diagnosis.

Sonoluminescence imaging in vivo

In this paper, a sonoluminescence (SL) image of living bodies were obtained with a high-sensitive imaging system for the first time. We found that some kind of chemiluminescent analytic agent, such as FCLA (Fluoresceinyl Cypridina Luminescent Analog) which can work in vivo, could enhance the SL by chemiluminescence through a chemical reaction with oxygen free radicals. In the experiment FCLA is used to enhance the biological SL of mouse body and a clear image of FCLA-enhanced SL was observed in vivo. The biological SL of several typical biological tissues are also investigated. The SL intensity from different tissues has significant difference. With confocal scanning technique, this SL imaging method has potential applications in clinical diagnosis.

FCLA-enhanced sonoluminescence imaging in vivo

In this paper, we report, for the first time, sonoluminescence (SL) images of living body (nude mouse) injected with and without chemical agents under weak ultrasound field. We found FCLA (Fluoresceinyl Cypridina Luminescent Analog), a chemiluminescent analytic agent, could enhance SL and can work in vivo. We also makes use of sonosensitization to produce tumor-selective oxygen radicals that can react with FCLA to emit chemiluminescence. By detecting this luminescence, we obtained a clear diagnostic image. This novel method proposed by our group has potential application in clinics for tumor early-stage diagnosis.