QUANTITATIVE DETECTION METHOD OF RARE EARTH DOPED CALCIUM PHOSPHATE FLUORESCENT NANOPARTICLES IN ORGANISMS
20200200777 ยท 2020-06-25
Inventors
Cpc classification
G01N33/94
PHYSICS
G01N21/6428
PHYSICS
International classification
G01N33/94
PHYSICS
Abstract
A quantitative detection method of rare earth doped calcium phosphate fluorescent nanoparticles (RE-nCaP) in organisms includes establishing a fluorescent intensity-concentration standard curve of rare earth ions, preparing samples to be tested and the blank control group into homogenate, performing centrifuging and testing the fluorescent intensity of supernatants, calculating the fluorescent intensity values per unit mass or volume of the samples and the blank control group, and performing significant difference analysis; if P is greater than or equal to 0.05, determining that the RE-nCaP content in the samples is 0, and if P is smaller than 0.05, testing the tissue extraction rate of RE-nCaP; and comprehensively considering the tissue extraction rate, the homogenate volume, the fluorescent intensity value per until mass or volume, the homogenate dilution ratio, and the doping amount to obtain the accurate content of the RE-nCaP in biological tissue samples.
Claims
1. A quantitative detection method of rare earth doped calcium phosphate fluorescent nanoparticles (RE-nCaP) in organisms, characterized by comprising the following steps: (a) establishing a fluorescent intensity-concentration standard curve of rare earth (RE) ions in a fluorescent enhancement liquid system; (b) separately treating biological tissue samples of the group to be tested, and biological tissue samples excluding RE-nCaP of the blank control group through an acid solution to obtain homogenates of the group to be tested and the blank control group; performing centrifugal separation on the homogenates of the two groups separately to obtain supernatants, diluting the supernatants with fluorescent enhancement liquid, then detecting the fluorescent intensity of the diluted supernatants, performing significant difference analysis on the fluorescent intensity values per unit mass or volume between the group to be tested and the blank control group, so as to determine if the biological tissue samples in the group to be tested contain RE-nCaP, and continuing to perform a step (c) and a step (d) to further determine the content of the RE-nCaP while the biological tissue samples are determined to contain RE-nCaP; (c) separately adding the RE-nCaP to the homogenate of the blank control group and the acid solution having the same volume as that of the homogenate, performing centrifugal separation to obtain supernatants, diluting the supernatants with the fluorescent enhancement liquid, detecting the fluorescent intensity of the diluted supernatants, calculating the tissue retention rate per unit mass or volume according to the fluorescent intensity of the homogenate of the blank control group and the fluorescent intensity of the acid solution, and further calculating the tissue extraction rate of the group to be tested according to the weight or the volume of biological tissues in the group to be tested; and (d) comprehensively considering the fluorescent intensity-concentration standard curve, the tissue extraction rate, the homogenate volume, the fluorescent intensity value per unit mass or volume, the dilution ratio and the doping amount of rare earth elements in calcium phosphate, and finally calculating the specific content of RE-nCaP in the biological tissue samples of the group to be tested.
2. The method according to claim 1, characterized in that an establishing method of the standard curve of the fluorescent intensity y and the concentration x in the step (a) comprises the following steps: by using the fluorescent enhancement liquid as a solvent, preparing a series of rare earth ion standard solutions of different concentrations, determining the fluorescent intensity of the rare earth ion standard solutions at the specific emission wavelength under the specific excitation wavelength through a fluorescent spectrophotometer, and performing fitting so as to obtain a straight line y=B+Nx, wherein B and N are constants.
3. The method according to claim 1, characterized in that the step (b) comprises the specific processes: accurately measuring the mass or the volume of the biological tissue samples in the group to be tested and the mass or the volume of the biological tissue samples excluding Eu-nCaP in the blank control group separately, then adding the acid solution to obtain the homogenates of the group to be tested and the blank control group; taking the homogenate in the group to be tested and the homogenate in the blank control group, wherein the amount of the homogenates is equivalent, and separately performing centrifugal separation to obtain supernatants; mixing the supernatants with the acid solution according to a certain proportion to obtain supernatant diluents; mixing the supernatant diluents with the fluorescent enhancement liquid according to a certain proportion to obtain mixed liquid; determining the fluorescent intensity of the mixed liquid at the specific emission wavelength under the specific excitation wavelength; according to a formula (I), calculating the fluorescent intensity value T of the tissues per unit mass or volume,
4. The method according to claim 1, characterized in that the specific method of the step (c) comprises the following steps: uniformly mixing an Eu-nCaP aqueous suspension of a certain concentration with the homogenate of the blank control group and the acid solution according to a certain proportion separately, allowing the obtained mixtures to stand, performing centrifugal separation to obtain supernatants, mixing the supernatants with the acid solution according to a certain proportion to obtain supernatant diluents, mixing the supernatant diluents with the fluorescent enhancement liquid according to a certain proportion to obtain test liquid, and determining the fluorescent intensity of the test liquid at the specific emission wavelength under the specific excitation wavelength; and calculating the tissue retention rate S per unit mass or volume according to a formula (II)
R=(1S.Math.W.sub.1)100% (III) wherein W.sub.1 is the weight or the volume of the tissue samples in the group to be tested.
5. The method according to claim 1, characterized by calculating the content M of RE-nCaP in the biological tissue samples of the group to be tested according to a formula (IV) in the step (d)
6. The method according to claim 1, characterized in that, the rare earth ions are specifically Eu.sup.3+ or Tb.sup.3+, and a rare earth ion doping manner is separate doping or codoping with other rare-earth elements.
7. The method according to claim 1, characterized in that, the value range of the molar ratio of RE/(RE+Ca) in the RE-nCaP is 0.1%-18%.
8. The method according to claim 1, characterized in that, the acid solution is specifically a nitric acid aqueous solution or a hydrochloric acid aqueous solution, and the concentration of the acid solution is 0.5-5 mol/L.
9. The method according to claim 1, characterized in that, the fluorescent intensity of the sample solution at the specific emission wavelength under the specific excitation wavelength is detected through a fluorescent spectrophotometer, the specific excitation wavelength is 330-350 nm, and the specific emission wavelength is 618 nm.
10. The method according to claim 1, characterized in that the biological tissue samples of the group to be tested and the control group are selected from any one of blood, hearts, livers, spleens, lungs, kidneys, pancreases, brains, lymph, skeletons, skins, nerves, tumors or excretion of animals or people.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
DETAILED DESCRIPTION OF THE INVENTION
[0029] In order to enable those skilled in the art to sufficiently understand the technical scheme and the beneficial effects of the quantitative detection method disclosed by the invention, further description is performed through combination with concrete embodiments.
[0030] The molar ratio of europium ion doped hydroxylapatite nanoparticles (Eu-nCaP, Eu/(Eu+Ca) used in the quantitative detection method disclosed by the invention is 4%, and the chemical molecular formula is Eu.sub.0.4Ca.sub.9.6(PO.sub.4).sub.6(OH).sub.2). The europium ion doped hydroxylapatite nanoparticles are prepared according to a method disclosed by the Chinese patent CN105018086A (rare earth doped calcium phosphate fluorescent nanoparticles and preparation method thereof, Hanyingchao, et al), the Chinese patent CN107573938A (preparation method and application of rare earth doped apatite fluorescent nanometer points, Hanyingchao, et al). Other rare earth ion (such as Tb) doped calcium phosphate nanoparticles can also be prepared by the method.
[0031] The biological tissue samples (livers, kidneys, pancreases, hearts, blood, tumors and the like) involved by the invention all come from nude mice, and all nude mouse experiments are all strictly executed according to Regulations for the Administrations of Affairs Concerning Experimental Animals in China and the regulations of relevant international laws and regulations. In embodiments 1-5, normal nude mice of which the weight is about 20 g are used for experiments, in embodiment 6, nude mice (of which the weight is about 20 g) having a subcutaneous transplanted tumor model (HepG2 cells) are used for experiments, and the size of the tumors is 200-300 mm.sup.3. In each embodiment, 6 nude mice in the same batch are used, and are randomly divided into 2 groups which are recorded as the group to be tested (an experimental group) and the blank control group. The fluorescent enhancement liquid used in the quantitative detection method disclosed by the invention is the DELFIA Enhancement Solution, and the manufacturer is PerkinElmer Inc.
[0032] The method for establishing the fluorescent intensity-concentration standard curve of rare earth ions disclosed by the invention specifically comprises the following steps of precisely weighing 36.641mg of europium chloride hexahydrate, and dissolving the weighed europium chloride hexahydrate in 100mL of ultra pure water to obtain europium ion storing liquid of which the concentration is 1 mmol/L; diluting the europium ion storing liquid into europium ion solutions of different concentrations (0.50000, 0.99502, 1.48522, 1.97044, 2.45098, 2.92654 and 3.86473, nmol/L) with the fluorescent enhancement liquid, and then determining the fluorescent intensity of the europium ion solutions of different concentrations at 618nm under the condition that the excitation wavelength is 340 nm with the fluorescent spectrophotometer; and drawing the relationship curve of the fluorescent intensity y and the concentration x in a rectangular coordinate system, and performing linear fitting so as to obtain y=B+Nx (R.sup.2=0.9960), wherein B is intercept (cps), the value of the intercept is 0.039, N is slope (cps/(nmol/L)), the value of the slope is 1.501, and the result is as shown in the
Embodiment 1
[0033] An Eu-nCaP aqueous suspension (200 L, 5 mg/mL) is injected into the nude mice in the group to be tested through caudal vein injection, and timing immediately starts. The nude mice in the blank control group are not subjected to injection treatment. 8 h later, the liver tissues of the nude mice in the group to be tested and the liver tissues of the nude mice in the blank control group are taken out and are thoroughly rinsed with a PBS solution, and 3 liver samples are obtained in each group (namely that 3 liver samples are obtained in the group to be tested, and 3 liver samples are obtained in the blank control group). After surface moisture is thoroughly absorbed with paper, the weight W(g) of each liver sample is weighed, wherein W.sub.1 in the group to be tested is sequentially 0.097 g, 0.070 g and 0.074 g, and W.sub.0 in the blank control group is sequentially 0.054 g, 0.102 g and 0.085 g. The tissue samples of the group to be tested and the blank control group are prepared into 1 mL of liver homogenate with 2 mol/L nitric acid. 0.5mL of the liver homogenate in the group to be tested and 0.5 mL of the liver homogenate in the blank control group are separately taken, and are put in centrifugal tubes, high speed centrifugation (5000 r/min) is performed, 40 L of supernatant and 760 L of nitric acid (2 mol/L) are mixed so that a supernatant diluent is prepared. 5 L of the supernatant diluent and 995 L of fluorescent enhancement liquid are mixed so that mixed liquid is prepared, and the fluorescent intensity of the mixed liquid at the emission wavelength of 618 nm (Ex=340 nm) is tested. The fluorescent intensity value yi in the group to be tested is sequentially 10.068 cps, 11.244 cps and 10.463 cps, and the fluorescent intensity value yo in the blank control group is sequentially 0.780 cps, 0.080 cps and 0.653 cps. The fluorescent intensity value (T) of the livers per unit mass in the group to be tested and the blank control group is calculated according to the formula (I):
The fluorescent intensity value Ti of the livers per unit mass in the group to be tested is sequentially 103.392 cps/g, 160.071 cps/g and 140.865 cps/g, and the fluorescent intensity value To of the livers per unit mass in the blank control group is sequentially 13.722 cps/g, 0.402 cps/g and 7.224 cps/g; through single factor variance analysis, compared with the To value in the blank control group, the Ti value in the group to be tested has significance difference (P=0.0017<0.05), and the result is seen in the
[0034] The extraction rate of the Eu-nCaP in the livers is calculated through the following steps: separately putting the homogenate in the blank control group and nitric acid (2 mol/L) having the same volume (500 L) as that of the homogenate in the blank control group in the centrifugal tubes, separately adding 760 L of Eu-nCaP suspension liquid (0.25 g/mL), performing uniform mixing, allowing the mixtures to stand for 4 h, and performing centrifuging; taking 40 L, of supernatants and 760 L of nitric acid (2 mol/L), and performing mixing to obtain supernatant diluents; taking 5 L of the supernatant diluent and 995 L of the fluorescent enhancement liquid, and performing mixing so as to obtain test liquid; testing the fluorescent intensity of the test liquid at the emission wave length of at 618 nm (Ex=340 nm), wherein the fluorescent intensity Ai of the homogenate in the blank control group is 2.375 cps, and the fluorescent intensity Ao in a nitric acid group is 2.421 cps, and calculating the tissue retention rate S per unit mass according to the formula (II):
Based on the calculated S=0.085, further calculating the tissue extraction rate R according to the formula (III):
R=(1S.Math.W.sub.1)100%, (III)
so that the liver extraction rate R in 3 groups to be tested is 97.8%, 98.4% and 98.3% sequentially. The content of the Eu-nCaP in the livers in the group to be tested is calculated through the following steps of according to the known fluorescent intensity-concentration standard curve, the fluorescent intensity value (T.sub.1) of the livers per unit mass in the group to be tested, the average value (
wherein in the embodiment, k is 4000/0.4=10.sup.4, V=1*10.sup.3 L, and
Embodiment 2
[0035] The kidneys of the nude mice in the group to be tested and the kidneys of the nude mice in the control group are obtained by the method in the embodiment 1, and 3 samples are contained in each group (3 samples are contained in the group to be tested, and 3 samples are contained in the blank control group); the weight W(g) of each kidney sample is weighed through a scales, wherein W.sub.1 in the group to be tested is sequentially 0.073 g, 0.054 g and 0.065 g, and W.sub.0 in the blank control group is sequentially 0.020 g, 0.161 g and 0.097 g; and the tissue samples of the group to be tested and the blank control group are prepared into 1 mL of kidney homogenate through the 2 mol/L nitric acid.
[0036] By the method in the embodiment 1, the kidney homogenate in the group to be tested and the kidney homogenate in the blank control group are prepared into mixed liquid, the fluorescent intensity value y of the mixed liquid is tested, the fluorescent intensity value y.sub.1 in the group to be tested is sequentially 4.555 cps, 2.822 cps and 2.498 cps, and the fluorescent intensity value y.sub.0 in the blank control group is sequentially 0.282 cps, 0.174 cps and 0.095 cps; through the formula (I), the T.sub.1 value in the group to be tested is calculated out to be 61.863 cps/g, 51.537 cps/g and 37.831 cps/g sequentially, and the To value in the blank control group is calculated out to be 1.215 cps/g, 0.839 cps/g and 0.577 cps/g sequentially; through single factor variance analysis, compared with the To value in the blank control group, the Ti value in the group to be tested has significant difference (P=0.0021<0.05), and the result is seen in the
[0037] According to the method in the embodiment 1, the fluorescent intensity value of the homogenate in the blank control group and the fluorescent intensity value of the nitric acid are tested, the retention rate S is calculated according to the formula (II), and further the extraction rate R of the Eu-nCaP in the kidneys is calculated according to the formula (III), wherein A.sub.1=2.279 cps, A.sub.0=2.421 cps and W.sub.0=0.097 g; and therefore, the kidney extraction rate R in the 3 groups to be tested is calculated to be 95.6%, 96.7% and 96.1%.
[0038] The content of the Eu-nCaP in the kidneys in the group to be tested is calculated through the following step: according to the formula (IV) (in the embodiment, B=0.039, N=1.501, V=1*10.sup.3L, k=10.sup.4,
Embodiment 3
[0039] The pancreases of the nude mice in the group to be tested and the pancreases of the nude mice in the control group are obtained by the method in the embodiment 1, and 3 samples are contained in each group (3 samples are contained in the group to be tested, and 3 samples are contained in the blank control group); the weight W(g) of each pancrease sample is weighed through a scales, wherein W.sub.1 in the group to be tested is sequentially 0.027 g, 0.029 g and 0.028 g, and W.sub.0 in the blank control group is sequentially 0.050 g, 0.033 g and 0.034 g; and the tissue samples in the group to be tested and the blank control group are prepared into 1mL of pancrease homogenate through the 2 mol/L nitric acid.
[0040] According to the method in the embodiment 1, the pancrease homogenate the group to be tested and the pancrease homogenate in the blank control group are prepared into mixed liquid, the fluorescent intensity value of the mixed liquid is tested, the fluorescent intensity value yi in the group to be tested is sequentially 1.245 cps, 1.256 cps and 1.320 cps, and the fluorescent intensity value yo in the blank control group is sequentially 0.312 cps, 0.491 cps and 0.495 cps; through the formula (I), the Ti value in the group to be tested is calculated to be 44.667, 41.966, 45.750 cps/g sequentially, and the To value in the blank control group is calculated to be 5.460, 13.679, 13.412 cps/g sequentially; through single factor variance analysis, compared with the To value in the blank control group, the Ti value in the group to be tested has significant difference (P=0.0003<0.05), and the result is seen in the
[0041] According to the method in the embodiment 1, the fluorescent intensity value of the homogenate in the blank control group and the fluorescent intensity value of the nitric acid are tested, the retention rate S is calculated according to the fluorescent intensity value, and the extraction rate R of the Eu-nCaP in the pancreases is further calculated, wherein A.sub.1=2.032 cps, A.sub.0=2.421cps and W.sub.0=0.050 g; and therefore, the pancrease extraction rate R in the 3 groups to be tested is calculated to be 91.32%, 90.68% and 91.00% from the formula (III).
[0042] The content of the Eu-nCaP in the pancreases in the group to be tested is calculated through the following step: according to the formula (IV) (in the embodiment, B=0.039, N=1.501, V=1*10.sup.3, k=10.sup.4,
Embodiment 4
[0043] Reference to the method in the embodiment 1, 0.04 mL (W) of blood of the nude mice in the group to be tested and 0.04 mL (W) of blood of the nude mice in the control group are separately collected, and the blood of the nude mice in the group to be tested and 1 mL of nitric acid (2 mol/L) are mixed and uniformly shaken, the blood of the nude mice in the control group and 1 mL of nitric acid (2 mol/L) are mixed and uniformly shaken, so that blood homogenates are prepared. 3 samples are contained in each group (3 samples are contained in the group to be tested, and 3 samples are contained in the blank control group).
[0044] According to the method in the embodiment 1, the fluorescent intensity of the blood homogenate in the group to be tested and the blood homogenate in the blank control group are tested, the fluorescent intensity yi in the group to be tested is sequentially 2.642 cps, 2.720 cps and 2.810 cps, and the fluorescent intensity value yo in the blank control group is sequentially 0.210 cps, 0.241 cps and 0.196 cps; through the formula (I), the T.sub.1 value in the group to be tested is calculated to be 65.075, 67.025, 69.275 cps/mL sequentially, and the T.sub.0 value in the blank control group is calculated to be 4.275, 5.050, 3.925 cps/mL sequentially; through single factor variance analysis, compared with the To value in the blank control group, the T.sub.1 value in the group to be tested has significant difference (P=0.000001<0.05), and the result is seen in the
[0045] According to the method in the embodiment 1, the fluorescent intensity value of the homogenate in the blank control group and the fluorescent intensity value of the nitric acid is tested, the retention rate S is calculated according to the fluorescent intensity value, and the extraction rate R of the Eu-nCaP in the blood is further calculated, wherein A.sub.1=2.323 cps, A.sub.0=2.421 cps and W.sub.0=0.04 mL; and therefore, the blood extraction rate R in the 3 groups to be tested is calculated from the formula (III) to be 98.9%. The content of the Eu-nCaP in the blood in the group to be tested is calculated through the following step: according to the formula (IV) (in the embodiment, B=0.039, N=1.501, V=1*10.sup.3, k=10.sup.4, T.sub.0=4.417), calculating the content of the Eu-nCaP in the blood in the group to be tested to be 409.026nmol/mL, 422.175nmol/mL and 437.347nmol/mL respectively, thereby obtaining the content of the Eu-nCaP in the blood tissue of the group to be tested being 422.84914.173nmol/mL.
Embodiment 5
[0046] The hearts of the nude mice in the group to be tested and the hearts of the nude mice in the control group are obtained by the method in the embodiment 1, and 3 samples are contained in each group (3 samples are contained in the group to be tested, and 3 samples are contained in the blank control group); the weight W(g) of each heart sample is weighed through a scales, wherein W.sub.1 in the group to be tested is sequentially 0.027 g, 0.024 g and 0.012 g, and W.sub.0 in the blank control group is sequentially 0.018 g, 0.063 g and 0.020 g; and the tissue samples in the group to be tested and the blank control group are prepared into 1 mL of heart homogenate through the 2 mol/L nitric acid.
[0047] According to the method in the embodiment 1, the heart homogenate in the group to be tested and the heart homogenate in the blank control group are prepared into mixed liquid, the fluorescent intensity value of the mixed liquid is tested, the fluorescent intensity value yi in the group to be tested is sequentially 0.133 cps, 0.410 cps and 0.120 cps, and the fluorescent intensity value y.sub.0 in the blank control group is sequentially 0.475cps, 0.117cps and 0.487cps; through the formula (I), the T.sub.1 value in the group to be tested is calculated to be 3.443, 15.394, 6.750 cps/g sequentially, and the T.sub.0 value in the blank control group is calculated to be 24.222, 1.238, 22.400 cps/g sequentially; through single factor variance analysis, P=0.416>0.05, indicating that compared with the To value in the blank control group, the Ti value in the group to be tested has no significant difference, and the result is seen in the
Embodiment 6
[0048] The tumor tissue of the nude mice in the group to be tested and the tumor tissue of the nude mice in the control group are obtained by the method in the embodiment 1, and 3 samples are contained in each group (3 samples are contained in the group to be tested, and 3 samples are contained in the blank control group); the weight W(g) of each tumor sample is weighed through a scales, wherein W.sub.1 in the group to be tested is sequentially 0.037 g, 0.027 g and 0.026 g, and W.sub.0 in the blank control group is sequentially 0.037 g, 0.115 g and 0.022 g; and the tissue samples in the group to be tested and the blank control group are prepared into 1 mL of tumor homogenate through the 2 mol/L nitric acid.
[0049] According to the method in the embodiment 1, the tumor homogenate in the group to be tested and the tumor homogenate in the blank control group are prepared into mixed liquid, the fluorescent intensity value of the mixed liquid is tested, the fluorescent intensity value yi in the group to be tested is sequentially 0.848, 0.810 and 0.861 cps, and the fluorescent intensity value yo in the blank control group is sequentially 0.368, 0.516 and 0.210 cps; through the formula (I), the Ti value in the group to be tested is calculated to be 21.865 cps/g, 28.556 cps/g and 31.615 cps/g sequentially, and the To value in the blank control group is calculated to be 8.892 cps/g, 4.148 cps/g and 7.773cps/g sequentially; through single factor variance analysis, compared with the To value in the blank control group, the Ti value in the group to be tested has significant difference (P=0.0032<0.01), and the result is seen in the
[0050] According to the method in the embodiment 1, the fluorescent intensity value of the homogenate in the blank control group and the fluorescent intensity value of the nitric acid are tested, the retention rate S is calculated according to the fluorescent intensity value, and further the extraction rate R of the Eu-nCaP in the tumors is calculated, wherein A.sub.1=2.323 cps, A.sub.0=2.421 cps and W.sub.0=0.115g; and therefore, the tumor extraction rate R in the 3 groups to be tested is calculated from the formula (III) to be 98.70%, 99.05% and 99.08%.
[0051] The content of the Eu-nCaP in the tumors in the group to be tested is calculated through the following step: according to the formula (IV) (in the embodiment, B=0.039, N=1.501, V=1*10.sup.3, k=10.sup.4,