Yonghong He

Experimental study on photodynamic diagnosis of cancer mediated by chemiluminescence probe

A novel method of photodynamic diagnosis of cancer mediated by chemiluminescence probe is presented. The mechanism for photodynamic therapy involves singlet oxygen (1O2) generated by energy transfer from photosensitizers. 1O2 can react with 3,7‐dihydro‐6‐{4‐{2‐(N′‐(5‐fluoresceinyl)thioureido)ethoxy}phenyl}‐2‐methylimidazo{1,2‐a}pyrazin‐3‐one sodium salt (FCLA), which is a Cypridina luciferin analog and a specific chemiluminescence probe for detecting 1O2 and superoxide (O2 −). The reaction of FCLA and 1O2 can give emission with peak wavelength at about 532 nm. In the present study, FCLA was chosen as an optical reporter of 1O2 produced from the photosensitization reaction of hematoporphyrin derivative in model solution and in nude mice with transplanted mammary cancer. Photosensitized chemiluminescence from the reaction of FCLA with 1O2 was detected by a highly sensitive Intensified Charge‐Coupled Device detector. The chemiluminescence was markedly inhibited by the addition of 10 mmol/l sodium azide (NaN3) to the model solution and minor effects were observed at the addition of 10 μmol/l superoxide dismutase, 20 mmol/l mannitol and 100 μg/ml catalase, respectively, thus indicating that 1O2 generation from photosensitization reaction mainly results in light emission. Experiments in vivo with tumor‐bearing mice showed a clear chemiluminescence image of tumor. The study suggests that this novel method may be applicable to the diagnosis of superficial tumors.

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.

AM ultrasound-modulated optical tomography with realtime FFT

We report on a novel ultrasound-modulated optical tomographic technique applied in dense tissue-simulating turbid media. A 1 MHz ultrasound beam is focused into the media to modulate and tag the scattering laser light passing through the ultrasonic focused zone. A 10 kHz sinusoidal wave, as a detection wave, is carried by the ultrasound beam through amplitude-modulation (AM). The scattering photons that come from the focused zone carry the modulated information, received by detector and demodulated by real-time fast Fourier transform (FFT). The optical tomographic images of the tissue simulating media and buried object are reconstructed with AM spectral intensity. This method can be applied to imaging three-dimensional tissue structures with different optical parameters. For the first time, we obtained the tomography of buried objects in biological tissue phantoms with a detecting depth of 30 mm.

A novel cancer imaging method using chemiluminescence-mediated sonosensitization

In this paper, we introduce a novel method named chemiluminescence mediated sono dynamic diagnosis (SDD), which is designed as follows: sonosensitizer is used to localize the cancer tissue, and is sonosensitized by the ultrasound field to produce oxygen free radicals. Then, another agent, FCLA (fluoresceinyl cypridina luciferin analog), reacts with1O2 to efficiently transform the chemical energy of1O2 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 chemiluminescence mediated SDD, we obtained a clear diagnostic image of a transplanted tumor in a nude mouse in the experiments. This method could have potential applications in clinics for early stage tumor diagnosis.

Sonoluminescence optical confocal tomography of tissue

Summary In this paper, we report experiments on optical confocal tomography by use of sonoluminescence signal in both biological tissue and tissue-simulating media. A high-sensitive confocal scanning setup based on photon counting technique was developed. With the system, we obtained images of the objects embedded in tissue-simulating turbid media. The images showed a high contrast and a lateral resolution of about 100 μm. We finally imaged a carbon stick buried in muscle tissue with the sonoluminescence confocal scanning tomography. This technique has potential applications in clinical diagnosis.

New method of ultrasound-modulated optical tomography

A new method of ultrasound-modulated optical tomography is reported, which ultrasound wave is amplitude modulated to increase detection sensitivity and signal-to-noise rate. Near-infrared laser is incident to tissue simulating medium and modulated by focused ultrasound. A buried object in simulating medium mis imaged with modulated multi-diffuse light that pass through ultrasound focal zone. The light signal is demodulated by real-time FFT. A two-dimensional tomographic image is obtained through scanning and detecting the ultrasound-modulated optical signal.

Ultrasound-modulated optical tomography with real-time FFT

A new method of ultrasound-modulated optical tomography is reported, in which the buried object in optical turbid media is imaged directly with frequency-domain signals by real-time FFT. Tunable near-infrared laser is modulated by focused ultrasound. 2D tomographic images are obtained through scanning and detecting the ultrasound-modulated optical signal. Multi-wavelengths laser and diverse frequency ultrasounds are used to study image quality.

A highly sensitive chemiluminescence method for early diagnosis of radiation damage

Chemiluminescence (CL) is a highly sensitive detection method with broad biological applications. In this work, a CL detection system is developed and applied in detection the CL from human lymphocyte induced with Co-60 irradiation, for the first time. The radiation damage of lymphocyte was detected by cell counting and MTT method for various irradiation doses. The results show a good correlation between the CL intensity and the radiation-induced damage of lymphocyte. Cell activity increased gradually with the increase of radiate dose, when the dose was under 3Gy. When the radiate dose was above 3Gy, the results were contrary. The cell counting results corresponded well with the MTT method. The CL detection method, thus, may provide an alternative way in evaluation of radiation damage.

High-sensitivity imaging method of singlet oxygen and superoxide anion in photodynamic and sonodynamic actions

A novel method of photodynamic diagnosis (PDD) of cancer mediated by chemiluminescence (CL) probe is presented. The mechanism for photodynamic therapy (PDT) involves reactive oxygen species (ROS), such as singlet oxygen (1O2) and superoxide (O2-), generated by during the photochemical process. Both 1O2 and O2- can react with Cypridina luciferin analogue (FCLA), a highly selective CL probe for detecting the ROS. Chemiluminescence from the reaction of FCLA with the ROS, at about 530 nm, was detected by a highly sensitive ICCD system. The CL was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) in a sample solution. Similar phenomena, with lesser extents of changes, were observed at the additions of 10 μmol/L superoxide dismutase (SOD), 10 mmol/L mannitol, and 100 μg/mL catalase, respectively. This indicates that the detected CL signals were mainly from ROS generated during the photosensitization reactions. Also, the chemiluminescence method was used to detect the ROS during sonodynamic action, both in vitro and in vivo. ROS formation during sonosensitizations of HpD and ATX-70 were detected using our newly-developed imaging technique, in real time, on tumor bearing animals. This method can provide a new means in clinics for tumor diagnosis.

In-vivo usable chemiluminescence probe carried by nanoparticles

Chemiluminescence analysis technique is an important method in biology and medicine. Because the reaction between chemiluminescence reagent and high-energy molecule is instantaneous and short-lived, the present chemiluminescence analysis methods have difficulty in living body. In this paper, a novel chemiluminescence probe was designed and used, which was made of human serum albumin and chemiluminescence reagent 2-Methyl-6- (p-methoxyphenyl) -3,7- dihydroimidazo [1,2-a]pyrazin-3-one (MCLA); It can be used to detect the distribution of super oxide anion and singlet oxygen in living body. Electron microscope observation indicated that the diameter of nanoparticles was about 50~150nm and the diameter among 50~80nm can come to 80%. The results in vitro and in vivo showed that the nanoparticles could release MCLA slowly. In vivo experiment, injected the Hematoporphyrin Derivative (HpD) and nanoparticles in the denuded site of mice, stimulated by visible light, then can see distinct lurninesce at the injected site through detecting the two-dimensional image using a highly sensitive Intensified Charged-Coupled Device (ICCD) detector. The results of experiment proved that the time delay resulted from nanoparticles is obvious.