Dataset Information

Noninvasive and Spatiotemporal Control of DNAzyme-Based Imaging of Metal Ions In Vivo Using High-Intensity Focused Ultrasound.

ABSTRACT: Detecting metal ions in vivo with a high spatiotemporal resolution is critical to understanding the roles of the metal ions in both healthy and disease states. Although spatiotemporal controls of metal-ion sensors using light have been demonstrated, the lack of penetration depth in tissue and in vivo has limited their application. To overcome this limitation, we herein report the use of high-intensity focused ultrasound (HIFU) to remotely deliver on-demand, spatiotemporally resolved thermal energy to activate the DNAzyme sensors at the targeted region both in vitro and in vivo. A Zn²⁺-selective DNAzyme probe is inactivated by a protector strand to block the formation of catalytic enzyme structure, which can then be activated by an HIFU-induced increase in the local temperature. With this design, Zn²⁺-specific fluorescent resonance energy transfer (FRET) imaging has been demonstrated by the new DNAzyme-HIFU probes in both HeLa cells and mice. The current method can be applied to monitor many other metal ions for in vivo imaging and medical diagnosis using metal-specific DNAzymes that have either been obtained or can be selected using in vitro selection.

SUBMITTER: Wang X

PROVIDER: S-EPMC9133526 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature

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Noninvasive and Spatiotemporal Control of DNAzyme-Based Imaging of Metal Ions In Vivo Using High-Intensity Focused Ultrasound.

Wang Xiaojing X Kim Gun G Chu James L JL Song Tingjie T Yang Zhenglin Z Guo Weijie W Shao Xiangli X Oelze Michael L ML Li King C KC Lu Yi Y

Journal of the American Chemical Society 20220318 13

Detecting metal ions in vivo with a high spatiotemporal resolution is critical to understanding the roles of the metal ions in both healthy and disease states. Although spatiotemporal controls of metal-ion sensors using light have been demonstrated, the lack of penetration depth in tissue and in vivo has limited their application. To overcome this limitation, we herein report the use of high-intensity focused ultrasound (HIFU) to remotely deliver on-demand, spatiotemporally ...[more]

PMID: 35302361

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Project description:The success of any minimally invasive treatment procedure can be enhanced significantly if combined with a robust noninvasive imaging modality that can monitor therapy in real time. Quantitative ultrasound (QUS) imaging has been widely investigated for monitoring various treatment responses such as chemotherapy, radiation, and thermal therapy. Previously, we demonstrated the feasibility of using spectral-based QUS parameters to monitor high-intensity focused ultrasound (HIFU) treatment of in situ tumors in euthanized rats [Ultrasonic Imaging 36(4), 239-255, 2014]. In the present study, we examined the use of spectral-based QUS parameters to monitor HIFU treatment of in vivo rat mammary adenocarcinoma tumors (MAT) where significant tissue motion was present. HIFU was applied to tumors in rats using a single-element transducer. During the off part of the HIFU duty cycle, ultrasound backscatter was recorded from the tumors using a linear array co-aligned with the HIFU focus. A total of 10 rats were treated with HIFU in this study with an additional sham-treated rat. Spectral parameters from the backscatter coefficient, i.e., effective scatterer diameter (ESD) and effective acoustic concentration (EAC), were estimated. The changes of each parameter during treatment were compared with a temperature profile recorded by a fine-needle thermocouple inserted into the tumor a few millimeters behind the focus of the HIFU transducer. The mean ESD changed from 121 ±6 to [Formula: see text], and the EAC changed from 33 ±2 to [Formula: see text] during HIFU exposure as the temperature increased on average from 38.7 ±1.0 (°)C to 64.2 ±2.7 (°)C. The changes in ESD and EAC were linearly correlated with the changes in tissue temperature during the treatment. When HIFU was turned off, the ESD increased from 81 ±8 to [Formula: see text] and the EAC dropped from 46 ±3 to 36±2 dB/cm(3) as the temperature decreased from 64.2 ±2.7 (°)C to 45 ±2.7 (°)C. QUS was demonstrated in vivo to track temperature elevations caused by HIFU exposure.

Project description:AimTo investigate the damaging effect of high-intensity focused ultrasound (HIFU) on cancer cells and the inhibitory effect on tumor growth.MethodsMurine H22 hepatic cancer cells were treated with HIFU at the same intensity for different lengths of time and at different intensities for the same length of time in vitro, the dead cancer cells were determined by trypan blue staining. Two groups of cancer cells treated with HIFU at the lowest and highest intensity were inoculated into mice. Tumor masses were removed and weighed after 2 wk, tumor growth in each group was confirmed pathologically.ResultsThe death rate of cancer cells treated with HIFU at 1 000 W/cm2 for 0.5, 1, 2, 4, 8, and 12 s was 3.11+/-1.21%, 13.37+/-2.56%, 38.84+/-3.68%, 47.22+/-5.76%, 87.55+/-7.32%, and 94.33+/-8.11%, respectively. A positive relationship between the death rates of cancer cells and the length of HIFU treatment time was found (r = 0.96, P<0.01). The death rate of cancer cells treated with HIFU at the intensity of 100, 200, 400, 600, 800, and 1 000 W/cm2 for 8 s was 26.31+/-3.26%, 31.00+/-3.87%, 41.97+/-5.86%, 72.23+/-8.12%, 94.90+/-8.67%, and 99.30+/-9.18%, respectively. A positive relationship between the death rates of cancer cells and the intensities of HIFU treatment was confirmed (r = 0.98, P<0.01). The cancer cells treated with HIFU at 1 000 W/cm2 for 8 s were inoculated into mice ex vivo. The tumor inhibitory rate was 90.35% compared to the control (P<0.01). In the experimental group inoculated with the cancer cells treated with HIFU at 1 000 W/cm2 for 0.5 s, the tumor inhibitory rate was 22.9% (P<0.01). By pathological examination, tumor growth was confirmed in 8 out of 14 mice (57.14%, 8/14) inoculated with the cancer cells treated with HIFU at 1 000 W/cm2 for 8 s, which was significantly lower than that in the control (100%, 15/15, P<0.05).ConclusionHIFU is effective on killing or damage of H22 hepatic cancer cells in vitro and on inhibiting tumor growth in mice ex vivo.

Project description:Pre-clinically, High Intensity Focused Ultrasound (HIFU) has been shown to safely and effectively occlude placental blood vessels in the acute setting, when applied through the uterus. However, further development of the technique to overcome the technical challenges of targeting and occluding blood vessels through intact skin remains essential to translation into human studies. So too does the assessment of fetal wellbeing following this procedure, and demonstration of the persistence of vascular occlusion. At 115 ± 10 d gestational age (term~147 days) 12 pregnant sheep were exposed to HIFU (n = 6), or to a sham (n = 6) therapy through intact abdominal skin (1.66 MHz, 5 s duration, in situ ISPTA 1.3-4.4 kW.cm-2). Treatment success was defined as undetectable colour Doppler signal in the target placental vessel following HIFU exposures. Pregnancies were monitored for 21 days using diagnostic ultrasound from one day before HIFU exposure until term, when post-mortem examination was performed. Placental vessels were examined histologically for evidence of persistent vascular occlusion. HIFU occluded 31/34 (91%) of placental vessels targeted, with persistent vascular occlusion evident on histological examination 20 days after treatment. The mean diameter of occluded vessels was 1.4 mm (range 0.3-3.3 mm). All pregnancies survived until post mortem without evidence of significant maternal or fetal iatrogenic harm, preterm labour, maternal or fetal haemorrhage or infection. Three of six ewes exposed to HIFU experienced abdominal skin burns, which healed without intervention within 21 days. Mean fetal weight, fetal growth velocity and other measures of fetal biometry were not affected by exposure to HIFU. Fetal Doppler studies indicated a transient increase in the umbilical artery pulsatility index (PI) and a decrease in middle cerebral artery PI as a result of general anaesthesia, which was not different between sham and treatment groups. We report the first successful application of fully non-invasive HIFU for occlusion of placental blood flow in a pregnant sheep model, with a low risk of significant complications. This proof of concept study demonstrates the potential of this technique for clinical translation.

Dataset Information

Noninvasive and Spatiotemporal Control of DNAzyme-Based Imaging of Metal Ions In Vivo Using High-Intensity Focused Ultrasound.

Publications

Noninvasive and Spatiotemporal Control of DNAzyme-Based Imaging of Metal Ions <i>In Vivo</i> Using High-Intensity Focused Ultrasound.

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