阅读说明：本技术 一种基于全氟戊烷的激光响应型分子探针的应用 (Application of perfluoropentane-based laser response type molecular probe ) 是由 陈世桢 丘茂松 王瑞芳 孙献平 周欣 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种基于全氟戊烷的激光响应型分子探针的应用,该分子探针同时用于～(19)F和～(129)Xe双核MRI探测,利用实体瘤的高通透性和滞留效应,分子探针能够被动靶向肿瘤区域,用于肺癌的探测,而且在激光照射下,全氟戊烷发生相变,最终导致～(19)F和～(129)Xe MRI信号消失,从而实现激光响应的～(19)F和～(129)Xe MRI信号从“打开”转变为“关闭”状态,能够确证磁共振信号来源于分子探针,避免出现假阳性信号的出现,提高诊断的精确度。(The invention discloses an application of a perfluoropentane-based laser response type molecular probe, and the molecular probe is simultaneously used for 19 F and 129 xe dual-core MRI detection, utilizes the high permeability and retention effect of solid tumors, molecular probes can passively target tumor regions for lung cancer detection, and perfluoropentane undergoes phase change under laser irradiationUltimately lead to 19 F and 129 the Xe MRI signal disappears, and laser response is achieved 19 F and 129 the Xe MRI signal is converted from an 'on' state to an 'off' state, so that the magnetic resonance signal can be confirmed to be originated from the molecular probe, the occurrence of false positive signals is avoided, and the diagnosis accuracy is improved.)

1. An application of a perfluoropentane-based laser response type molecular probe in preparing a magnetic resonance imaging agent.

2. Use of a perfluoropentane-based laser-responsive molecular probe according to claim 1, wherein: the perfluoropentane-based laser response type molecular probe is used as¹²⁹Xe/¹⁹F binuclear MRI contrast agents.

3. Use of a perfluoropentane-based laser-responsive molecular probe according to claim 1, wherein: the laser response type molecular probe based on the perfluoropentane is of a core-shell structure, the perfluoropentane is an inner core, the polypyrrole is an inner shell layer, and the bovine serum albumin is an outer shell layer.

Technical Field

The invention belongs to the technical field of nuclear magnetic resonance imaging, and particularly relates to application of a perfluoropentane-based laser response type molecular probe.

Background

Magnetic Resonance Imaging (MRI) plays an important role in the diagnosis of tumors, and has the characteristics of high spatial resolution, no ionizing radiation and good soft tissue Imaging contrast. The magnetic resonance imaging which is commonly used in clinic at present is based on the imaging of water protons, and the imaging is interfered by the background signals of normal tissues on one hand and has low proton sensitivity on the other hand. In addition, the proton contrast agent is classified as T₁And T₂A contrast agent. T is₂The contrast agent is generally an iron-based nano material, is negative contrast, and is easily misjudged by internal endogenous iron or interferents such as blood clots. T is₁The main stream of contrast agents is gadolinium-based contrast agents, which have been warned by the FDA in the united states and are prone to induce renal fibrosis, and patients with renal and hepatic insufficiency are more serious. Based on this, the development of molecular probes free from biological background signals and having high sensitivity is of far reaching importance in the diagnosis of tumors.

¹⁹The nuclear spin of F is 1/2, the natural abundance is 100%, in¹⁹F MRI process without the need for¹⁹F isotope enrichment is carried out.¹⁹F has the advantage of no interference of background signals, because only trace amount of F exists in teeth and bones in human bodies or other animal bodies¹⁹F (less than 10)^-6M) in the form of solids¹⁹The transverse relaxation time of F is short, the signal attenuation is too fast in the magnetic resonance signal detection process, and the traditional nuclear magnetic resonance detection method is difficult to detect.¹²⁹Xe is a non-toxic, harmless inert gas with a natural abundance of 26.44%, a spin quantum number I-1/2, comparable to isotopic nuclei useful for NMR studies¹³¹Xe has higher magnetic spin ratio, higher sensitivity and longer relaxation time, is more suitable for the research of magnetic resonance contrast agents, and is hyperpolarized by laser¹²⁹Xe exhibits an ultra high sensitivity. In addition, bondingThe Chemical Exchange Saturation Transfer (CEST) technique can be further improved¹²⁹The sensitivity of Xe magnetic resonance is 4 to 5 orders of magnitude.

At present, few literature reports exist¹⁹F/¹²⁹Xe binuclear MRI probe (ACS appl. Bio Mater,2019,2,27-32), integration¹⁹F and¹²⁹the advantages of both Xe, combined with the CEST technique, develop intelligent response type¹⁹F/¹²⁹The Xe binuclear MRI probe can obtain more information of a tumor part on one hand, confirms the existence of the tumor from more layers, can further determine a probe molecule targeting tumor area on the other hand, improves the diagnosis accuracy, and has important significance for early and accurate diagnosis of the tumor.

Disclosure of Invention

Based on the prior art, the invention provides application of a perfluoropentane-based laser response type molecular probe, and the molecular probe is simultaneously used for¹⁹F and¹²⁹xe dual-core MRI detection, the molecular probe can passively target a tumor region by utilizing the high permeability and retention effect of a solid tumor for detecting lung cancer, and perfluoropentane undergoes phase change under laser irradiation to finally cause¹⁹F and¹²⁹the Xe MRI signal disappears, and laser response is achieved¹⁹F and¹²⁹the Xe MRI signal is converted from an 'on' state to an 'off' state, so that the magnetic resonance signal can be confirmed to be originated from the molecular probe, the occurrence of false positive signals is avoided, and the diagnosis accuracy is improved.

The technical scheme adopted for realizing the above purpose of the invention is as follows:

an application of a perfluoropentane-based laser response type molecular probe in preparing a magnetic resonance imaging agent.

Further, the perfluoropentane-based laser response type molecular probe is used as¹²⁹Xe/¹⁹F binuclear MRI contrast agents.

Furthermore, the laser response type molecular probe based on perfluoropentane is of a core-shell structure, perfluoropentane is an inner core, polypyrrole is an inner shell layer, and bovine serum albumin is an outer shell layer.

Compared with the prior art, the invention has the advantages and beneficial effects that:

1. the preparation method of the molecular probe is relatively simple, convenient and fast to operate, relatively short in time consumption and relatively low in preparation cost, and the application prospect of the molecular probe in the aspect of magnetic resonance molding is further expanded.

2. The molecular probe takes perfluoropentane as an inner core, sequentially wraps polypyrrole and bovine serum albumin outside the perfluoropentane, can firmly wrap the perfluoropentane inside, and ensures that the perfluoropentane is protected¹⁹F/¹²⁹Testing of Xe MRI.

3. In the molecular probe, perfluoropentane is a low-boiling-point fluoride, the boiling point of perfluoropentane is 29 ℃ at normal temperature and normal pressure, and the molecular probe can be used for preparing the low-boiling-point perfluoropentane¹⁹F MRI, and¹²⁹xe gas has high solubility in perfluoropentane and can be used for¹²⁹Xe MRI, polypyrrole has good photothermal conversion performance, and bovine serum albumin is used for improving the biocompatibility of the molecular probe. The molecular probes can be simultaneously detected before laser irradiation¹⁹F and¹²⁹xe dual-core MRI signal is in an 'open' state, the photothermal conversion performance of polypyrrole enables the temperature of a molecular probe system to rise after laser irradiation, perfluoropentane generates phase change when the temperature exceeds the boiling point of perfluoropentane by 29 ℃, and perfluoropentane is dissolved in perfluoropentane¹²⁹Xe also volatilizes with it, in which case¹⁹F and¹²⁹the Xe binuclear MRI signals are not detected and are in an off state.

4. The molecular probe ultrasonically converts perfluoropentane into nano-emulsion by an emulsification method, and then packages polypyrrole and bovine serum albumin, so that sufficient perfluoropentane can be packaged in the probe to generate¹⁹F MRI test is good.

5. Of the molecular probe¹²⁹Xe CEST effect is good, measured¹²⁹Has a relatively slow Xe exchange rate and is very suitable for use¹²⁹Xe CEST detection.

6. The molecular probe has good biocompatibility and water dispersibility, is suitable for living MRI, and has good application prospect in the aspect of early diagnosis of tumors.

Drawings

Fig. 1 is a schematic structural view of a perfluoropentane-based laser-responsive molecular probe prepared in example 1. Fig. 2 is a TEM image of a perfluoropentane-based laser-responsive molecular probe prepared in example 1.

FIG. 3 is a photothermographic chart of a perfluoropentane-based laser-responsive molecular probe prepared in example 1.

FIG. 4 is an SDS-PAGE gel of the perfluoropentane-based laser-responsive molecular probe and bovine serum albumin prepared in the examples.

FIG. 5 shows the preparation of perfluoropentane-based laser-responsive molecular probe prepared in example 1¹⁹F NMR spectrum.

FIG. 6 shows the perfluoropentane-based laser-responsive molecular probes prepared in example 1 at different concentrations¹⁹F MRI images.

FIG. 7 shows the perfluoropentane-based laser-responsive molecular probes prepared in example 1 at different concentrations¹²⁹Xe CEST spectra.

FIG. 8 shows that the hollow mesoporous organosilicon sphere prepared in example 1 is loaded with perfluoropentane nanomaterial¹²⁹Xe CEST spectra.

FIG. 9 shows the perfluoro-pentane-based laser-responsive molecular probes prepared in example 1 at different saturation pulse powers¹²⁹Xe CEST spectra.

FIG. 10 is the laser response of the perfluoropentane-based laser-responsive molecular probe prepared in example 1¹⁹F MRI signal change map.

FIG. 11 shows the laser response of the perfluoropentane-based laser-responsive molecular probe prepared in example 1¹²⁹Xe MRI signal change maps.

Fig. 12 is a photo-thermal curve of the perfluoropentane-based laser-responsive molecular probe prepared in example 1 under laser irradiation and a photo-thermal imaging graph corresponding thereto.

FIG. 13 shows the in vivo lung cancer treatment with laser irradiation of the perfluoropentane-based laser-responsive molecular probe prepared in example 1¹H MRI and¹⁹f MRI images.

Fig. 14 is a photothermal curve and a corresponding photothermal map of a living lung cancer under laser irradiation of the perfluoropentane-based laser-responsive molecular probe prepared in example 1.

Detailed Description

The present invention will be described in detail with reference to specific examples.

Example 1

Adding 5mL of 5% polyvinyl alcohol aqueous solution into 200 μ L of perfluoropentane (PFP), performing ultrasonic treatment in ice bath for 30min to obtain a mixed solution, slowly dripping the mixed solution into 14mL of ice water, and adding 1mL of 0.8M FeCl after dripping₃And stirring the solution for 30min, adding 28 mu L of pyrrole monomer, continuously stirring for 24h at 4 ℃ to polymerize the pyrrole monomer into polypyrrole, then adding 200mg of Bovine Serum Albumin (BSA), continuously stirring for 12h, after the reaction is finished, washing the obtained mixed product with ultrapure water, centrifuging for 10min at the rotating speed of 2000rpm, repeating the washing and centrifuging for three times to obtain the perfluoropentane-based laser response type molecular probe which is marked as PFP @ PPy @ BSA, and dispersing the obtained PFP @ PPy @ BSA in sterile PBS for later use and marked as PFP @ PPy @ BSA mother solution.

The structural schematic diagram of the laser-responsive molecular probe based on perfluoropentane prepared in this example is shown in fig. 1, and it can be known from fig. 1 that the inner core of the prepared PFP @ PPy @ BSA is perfluoropentane, the inner shell layer is polypyrrole, and the outer shell layer is bovine serum albumin.

The perfluoropentane-based laser response type molecular probe prepared in the embodiment is scanned by a transmission electron microscope, and an obtained TEM image is shown in FIG. 2, and as can be seen from FIG. 2, the prepared PFP @ PPy @ BSA has a good form and is of a core-shell structure, which indicates that polypyrrole and bovine serum albumin are successfully coated outside perfluoropentane. To further demonstrate that polypyrrole and bovine serum albumin were present on the surface of perfluoropentane, the photothermal effect of polypyrrole was first tested using its good photothermal conversion performance, and the results are shown in FIG. 3 at a power density of 1W/cm²Under the irradiation of 808nm laser, the solution is continuously irradiated for 3min, the final temperature of the molecular probe solution with different mass concentrations is increased along with the increase of the mass concentration of the molecular probe PFP @ PPy @ BSA, and the good polypyrrole is fully provedPhotothermal conversion performance, indicating that polypyrrole was coated. Secondly, in order to verify whether the molecular probe has bovine serum albumin, the molecular probe PFP @ PPy @ BSA and the bovine serum albumin sample are respectively subjected to a polyacrylamide gel electrophoresis experiment, the result is shown in figure 4, the PFP @ PPy @ BSA and the pure bovine serum albumin have similar electrophoresis bands, the electrophoresis bands of the PFP @ PPy @ BSA and the pure bovine serum albumin have the same positions, and the band color is darker due to the fact that the concentration of the bovine serum albumin is higher, and the experiment proves that the bovine serum albumin is successfully coated on the surface of the nano material PFP @ PPy.

The PFP @ PPy @ BSA prepared in this example was subjected to¹⁹F NMR test, performing qualitative analysis on perfluoropentane, adding trifluoroethanol as an internal standard substance for quantitative analysis, and obtaining¹⁹The F NMR spectrum is shown in FIG. 5, and it can be seen from FIG. 5 that PFP @ PPy @ BSA was obtained¹⁹F NMR showed identity with perfluoropentane¹⁹F NMR signal peak, confirming that the core of the molecular probe prepared in the example is perfluoropentane (PFP), and calculating the concentration of the perfluoropentane in the PFP @ PPy @ BSA mother liquor to be 18mM according to the concentration of the internal standard substance and the area ratio of the internal standard substance to the PFP @ PPy @ BSA characteristic peak at (-76.7 ppm).

PFP @ PPy @ BSA as prepared in this example was run at various concentrations¹⁹F MRI test, obtained¹⁹As shown in FIG. 6, it can be seen from FIG. 6 that as the concentration of perfluoropentane in the molecular probe PFP @ PPy @ BSA solution increases,¹⁹the F MRI signal intensity gradually increases.

PFP @ PPy @ BSA as prepared in this example was run at various concentrations¹²⁹Xe CEST test, obtained¹²⁹Xe CEST spectra are shown in FIG. 7, and it can be seen from FIG. 7 that as the concentration of perfluoropentane in the molecular probe PFP @ PPy @ BSA solution increases,¹²⁹the Xe CEST signal intensity gradually increases. Meanwhile, a hollow mesoporous organic silicon sphere is loaded with a nano material of perfluoropentane (doctor thesis: tumor multi-mode imaging based on mesoporous organic silicon oxide and synergistic treatment guided by the same, author: Machilus rupestris)¹²⁹Xe CEST test is taken as a control, and as shown in FIG. 8, the nano material with the hollow mesoporous organic silicon spheres loaded with perfluoropentane can be detected at 70 ppm, 80ppm, 100 ppm and 120ppm¹²⁹Xe CEST signal, which¹²⁹The Xe CEST signal is very unstable, mainly because of¹²⁹The Xe electron cloud is very sensitive to the environment,¹²⁹the Xe chemical shift is easy to change along with the change of the surrounding environment, especially for low-boiling perfluoropentane, the molecular motion is more intense, and the Xe chemical shift is dissolved in the perfluoropentane¹²⁹Xe CEST is not readily stabilized, indicating that the patent is stable¹²⁹Xe CEST signals have great difficulty. The PFP @ PPy @ BSA (PFP @ PPy @ BSA stock solution) prepared in this example was subjected to different saturation pulse powers¹²⁹Xe CEST test, obtained¹²⁹As shown in fig. 9, it can be seen from fig. 9 that, as the saturation pulse power increases,¹²⁹the Xe CEST signal intensity is gradually increased, and the molecular probe PFP @ PPy @ BSA is calculated by matlab software¹²⁹Xe exchange rate of 365s^-1Is very suitable for¹²⁹Xe CEST detection.

Test I, the laser response of the perfluoropentane-based laser response type molecular probe¹⁹F and¹²⁹xe binuclear magnetic resonance signal transition test

First, laser responsive¹⁹F magnetic resonance signal transition test

The test method comprises the following steps:

1. the PFP @ PPy @ BSA mother liquor prepared in example 1 (the concentration of perfluoropentane in the PFP @ PPy @ BSA mother liquor is 18mM) was diluted to prepare a test sample solution with a perfluoropentane concentration of 7 mM;

2. the test sample solution is carried out in a 9.4T magnetic resonance micro-imaging system¹⁹F, MRI test, adding the test sample solution into the nuclear magnetic sample tube, connecting the nuclear magnetic sample tube, placing into a nuclear magnetic spectrometer, continuously irradiating with near infrared laser for 10min, and performing MRI again¹⁹F MRI, after observing laser irradiation¹⁹Whether the F MRI signal can transition from the "on" to the "off state,¹⁹RARE imaging sequence, T, was selected for F MRI testing_RIs 3000ms, T_E3ms, the FOV size is 4.0 multiplied by 4.0cm, the layer thickness is selected to be 40mm, the matrix size is set to be 32 multiplied by 32, the acceleration factor is set to be 4, and sampling is carried out for 64 times;

and (3) test results:

laser response of PFP @ PPy @ BSA prepared in example 1¹⁹The F MRI signal change profile is shown in FIG. 10. it can be seen from FIG. 10 that the molecular probe PFP @ PPy @ BSA was used before laser irradiation¹⁹The F MRI signal is very bright, after 10min of laser irradiation,¹⁹f MRI signals are completely darkened, which shows that the laser response type molecular probe based on perfluoropentane realizes laser stimulation response at the solution level¹⁹The F MRI signal transitions from "on" to "off.

Two, laser responsive¹²⁹Xe magnetic resonance signal transition test

The test method comprises the following steps:

1. the PFP @ PPy @ BSA mother liquor prepared in example 1 (the concentration of perfluoropentane in the PFP @ PPy @ BSA mother liquor is 18mM) was diluted to prepare a test sample solution with a perfluoropentane concentration of 7 mM;

2. the test sample solution is carried out on a 9.4T magnetic resonance micro-imaging spectrometer¹²⁹Xe CEST test by adding a test sample solution to a nuclear magnetic sample cell and opening¹²⁹Heating Xe hyperpolarization device to 30 min-160 deg.C, turning on laser, connecting nuclear magnetic sample tube, placing in nuclear magnetic spectrometer, controlling sample temperature at 25 deg.C, tuning, shimming, introducing hyperpolarization¹²⁹Xe gas, the signal acquisition is carried out, the saturation irradiation power is 6.5 mu T, the irradiation time is 5s, and the sample acquisition in the nuclear magnetic sample tube is finished once¹²⁹After Xe CEST spectral data, 808nm laser (power density 400 mW/cm) was used²) Collecting again after irradiating for 10min¹²⁹Xe CEST spectral data and a plurality of Xe CEST spectral data,¹²⁹the Xe CEST spectra were collected over a chemical shift range of 60-220ppm at every 2ppm in the range of 60-80ppm, at every 5ppm in the range of 80-190ppm, at every 2ppm in the range of 190-200ppm and at every 5ppm in the range of 200-220 ppm.

And (3) test results:

laser response of PFP @ PPy @ BSA prepared in example 1¹²⁹The Xe CEST signal change profile is shown in FIG. 11, and it can be seen from FIG. 11 that the molecular probe PFP @ PPy @ BSA before laser irradiation has¹²⁹Xe CEST signal is very strong, CEST effect is 62% at the position corresponding to 72ppm after 10min of laser irradiation¹²⁹Xe CEST signals completely disappear, and the fact that the perfluoropentane-based laser response type molecular probe can realize laser stimulation response on the solution layer surface is shown¹²⁹The Xe CEST signal transitions from "on" to "off.

The photothermal curve and the corresponding photothermal image of PFP @ PPy @ BSA prepared in example 1 under laser irradiation are shown in FIG. 12, and it can be seen from FIG. 12 that after 10min of laser irradiation, the temperature reaches 44.8 ℃ and exceeds the boiling point of perfluoropentane by 29 ℃, thus causing the phase change of perfluoropentane, and finally realizing¹⁹F/¹²⁹The Xe binuclear magnetic resonance signal transitions from an "on" to an "off state.

Experiment II, Living Lung cancer of laser response type molecular probe based on perfluoropentane of the invention¹⁹F MRI test

The test method comprises the following steps:

1. PFP @ PPy @ BSA synthesized in example 1 (prepared according to the concentration of the PFP @ PPy @ BSA stock solution prepared in example 1) was prepared as a molecular probe solution with a perfluoropentane concentration of 36 mM;

2. culturing lung cancer A549 cells, wherein the culture solution is MEM (bovine embryo serum with volume fraction of 10% and penicillin-streptomycin with volume fraction of 1%), culturing at 37 ℃, digesting the lung cancer A549 cells with pancreatin when the cells grow to about 90% of a culture dish, injecting the digested A549 cells into the right hind leg of a blab/c nude mouse in a subcutaneous injection mode, and growing for about 20 days to obtain a blab/c nude mouse model of the lung cancer;

3. 200 mul of molecular probe solution is injected into a lung cancer model nude mouse by tail vein injection, and MRI test is carried out 24h after vein injection: 1. to carry out¹H MRI: selection of RARE imaging sequence, T_RIs 2500ms, T_E33ms, FOV size of 3.5 × 3.5cm, and acceleration factor of 8; 2. to carry out¹⁹F MRI: the first time after the test¹⁹After F MRI, 808nm laser irradiation is applied to the lung cancer area for 15min, and the laser power density is 400mW/cm²After the irradiation is finished, the process is carried out again¹⁹F MRI, Lung cancer ObservationOf a region¹⁹Whether the F MRI signal will transition from "on" to "off" state, the living body¹⁹RARE imaging sequence, T, was selected for F MRI experiments_R4000ms, T_E3ms, the FOV size is 4.32 multiplied by 4.32cm, the acceleration factor is set to be 4, and the sampling is carried out for 128 times;

and (3) testing results:

the lung cancer tumor is carried out after a nude mouse tail vein is injected with a molecular probe PFP @ PPy @ BSA for 24h¹H MRI and¹⁹f MRI, as can be seen from figure 13,¹h MRI allows for the visualization of regions of the tumor, corresponding tumor regions,¹⁹f MRI showed good imaging effect, and after 808nm laser irradiation was applied to the tumor region for 15min, it was performed again¹H MRI and¹⁹f MRI, as a result, found that of the tumor region¹⁹F MRI signals almost completely disappear, so that the perfluoropentane-based laser response type molecular probe can realize the response of laser stimulation on the surface of a living body¹⁹The F MRI signal transitions from an "on" state to an "off state.

The results of thermal imaging of the tumor area irradiated by laser are shown in fig. 14, the temperature of the tumor area reached 46.5 ℃ after laser irradiation for 15min, the boiling point of PFP under the in vivo relatively high pressure condition was reported to be in the range of 40-50 ℃, and the temperature of the tumor area after laser irradiation was also in this range, thus PFP phase transition of live lung cancer could be realized¹⁹The F MRI signal transitions from an "on" to an "off state.

The results show that the molecular probe PFP @ PPy @ BSA of the invention can be used for the background-free application of the living lung cancer¹⁹F MRI detection can be realized under the irradiation of near-infrared laser¹⁹Conversion of F MRI signals for further confirmation¹⁹The F MRI signal is derived from a molecular probe PFP @ PPy @ BSA, so that the occurrence of false positive signals can be avoided, and the tumor diagnosis accuracy is improved.