Switching-type fluorescent nanoparticle probe, and fluorescent molecular imaging method using same

Patent metadata

Field	Value
Publication number	US-9849197-B2
Application number	US-201214002327-A
Country	US
Kind code	B2
Filing date	Mar 1, 2012
Priority date	Mar 2, 2011
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

[Problem] To provide a novel fluorescent nanoparticle imaging probe having a switching function (a function to quench a fluorescent dye in a blood component and emit fluorescence in a tumor or an inflamed site to be imaged).
[Solution] A fluorescent nanoparticle probe comprising: a molecular assembly composed of an amphiphilic block polymer having a hydrophilic block chain and a hydrophobic block chain; and a fluorescent dye encapsulated in the assembly, wherein (a) the hydrophilic block chain comprises, as an essential hydrophilic structural unit, a unit selected from a sarcosine unit and an alkylene oxide unit, (b) the hydrophobic block chain comprises, as an essential hydrophobic structural unit, a unit selected from the group consisting of an amino acid unit and a hydroxylic acid unit, and (c) the fluorescent dye is a polylactic acid-bound cyanine compound comprising: a fluorescent group represented by the formula (I):

and a polylactic acid group having 5 to 50 lactic acid units, and two or more molecules of the fluorescent dye are encapsulated in the single molecular assembly.

First claim

The invention claimed is:

1. A fluorescent nanoparticle probe comprising:
a molecular assembly composed of an amphiphilic block polymer having a hydrophilic block chain and a hydrophobic block chain; and
a fluorescent dye encapsulated in the molecular assembly, wherein
(a) an essential hydrophilic structural unit is defined as a unit selected from a sarcosine unit and an alkylene oxide unit, and the hydrophilic block chain has 20 or more essential hydrophilic structural units,
(b) an essential hydrophobic structural unit is defined as a unit selected from the group consisting of an amino acid unit and a hydroxylic acid unit, and the hydrophobic block chain has 15 or more essential hydrophobic structural units, and
(c) the fluorescent dye is a polylactic acid-bound cyanine compound comprising:
a fluorescent group represented by the following structural formula (I):

wherein R 1 is a hydrocarbon group which may be substituted, and R 2 is a bivalent hydrocarbon group which may be substituted; A′ is an anion and m is 0 or 1; a ring B and a ring D may be the same or different from each other and each is a nitrogen-containing heterocycle; and L is a linking group that constitutes a polymethine chain, which may include a ring structure, and which may be substituted; and
a polylactic acid group having 5 to 50 lactic acid units, and
two or more molecules of the fluorescent dye are encapsulated in a self-quenching state by association in the single molecular assembly,
wherein the fluorescent dye is encapsulated in the molecular assembly in an amount of 5 to 20 mol % with respect to a total amount of the amphiphilic block polymer and the fluorescent dye so that the fluorescent nanoparticle remains self-quenching state by contact with a blood component.

2. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent dye is encapsulated in the molecular assembly in an amount of 10 to 20 mol % with respect to a total amount of the amphiphilic block polymer and the fluorescent dye.

3. The fluorescent nanoparticle probe according to claim 1 , wherein fluorescence intensity when brought into contact with or incorporated into a cell is 10 times or more higher than that when brought into contact with a blood component.

4. The fluorescent nanoparticle probe according to claim 1 , wherein the linking group represented by L has either of the following structures:

wherein R 3 and R 3 ′ are hydrogen or are linked together to form the ring structure; and X is hydrogen or a halogen.

5. The fluorescent nanoparticle probe according to claim 1 , wherein the ring B has either of the following structures:

wherein R 1 is a hydrocarbon group which may be substituted; and R 4 and R 5 are each hydrogen or an anionic substituent group, or are linked together to form an aryl ring, and
the ring D has either of the following structures:

wherein R 2 is a bivalent hydrocarbon group which may be substituted; and R 4 and R 5 are each hydrogen or an anionic substituent group, or are linked together to form an aryl ring.

6. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent group is represented by the following structural formula (II):

wherein R 1 is a hydrocarbon group which may be substituted, R 2 is a bivalent hydrocarbon group which may be substituted; R 3 and R 3 ′ are hydrogen or are linked together to form a ring structure; X is hydrogen or a halogen; A″ is an anion and m is 0 or 1; and R 4 and R 5 are each hydrogen or an anionic substituent group or are linked together to form an aryl ring.

7. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent group is represented by the following structural formula (III):

wherein R 2 is a bivalent hydrocarbon group which may be substituted.

8. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent group is represented by the following structural formula (IV):

wherein R 2 is a bivalent hydrocarbon group which may be substituted.

9. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent group is represented by the following formula (X):

wherein R 2 is a bivalent hydrocarbon group which may be substituted.

10. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent dye is represented by the following formula (III-i):

wherein n is an integer of 5 to 50.

11. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent dye is represented by the following formula (IV-i):

wherein n is an integer of 5 to 50.

12. The fluorescent nanoparticle probe according to claim 1 , wherein the fluorescent dye is represented by the following formula (X-i):

wherein n is an integer of 5 to 50.

13. The fluorescent nanoparticle probe according to claim 1 , wherein the hydrophobic block chain is selected from the group consisting of:
a hydrophobic polypeptide chain having 10 or more hydrophobic amino acid units,
a hydrophobic polyester chain having 15 or more hydroxylic acid units, and
a hydrophobic depsipeptide chain having a total of 20 or more units of both an amino acid unit and a hydroxylic acid unit.

14. The fluorescent nanoparticle probe according to claim 1 , wherein the hydrophobic block chain is a hydrophobic block chain having 25 or more lactic acid units.

15. The fluorescent nanoparticle probe according to claim 1 , wherein the hydrophilic block chain has an antibody, and a surface of the probe is modified with the antibody.

16. The fluorescent nanoparticle probe according to claim 15 , wherein the antibody is an antibody against a substance contained in a tumor.

17. A fluorescent molecular imaging method comprising the steps of:
administering the fluorescent nanoparticle probe according to claim 1 to a non-human animal; and
detecting fluorescence.

Assignees

• Saji Hideo
• Kimura Shunsaku
• Ono Masahiro
• Temma Takashi
• Hara Isao
• Ozeki Eiichi
• Univ Kyoto
• Shimadzu Corp

Inventors

• Saji Hideo
• Kimura Shunsaku
• Ono Masahiro
• Temma Takashi
• Hara Isao
• Ozeki Eiichi

Classifications

• A61K49/0034

  Indocyanine green, i.e. ICG, cardiogreen · CPC title

• A61K49/0032 Primary

  Methine dyes, e.g. cyanine dyes · CPC title

• A61K49/0093

  Nanoparticle, nanocapsule, nanobubble, nanosphere, nanobead, i.e. having a size or diameter smaller than 1 micrometer, e.g. polymeric nanoparticle · CPC title

• A61K49/0069

  the agent being in a particular physical galenical form · CPC title

• A61K49/0054 Primary

  Macromolecular compounds, i.e. oligomers, polymers, dendrimers · CPC title