U.S. patent application number 11/571397 was filed with the patent office on 2008-02-14 for water-soluble nanoparticles stabilized with multi-functional group ligands and method of preparation thereof.
This patent application is currently assigned to YONSEI UNIVERSITY. Invention is credited to Jin-Woo Cheon, Jin-Sil Choi, Young-Wook Jun.
Application Number | 20080038361 11/571397 |
Document ID | / |
Family ID | 36000248 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080038361 |
Kind Code |
A1 |
Cheon; Jin-Woo ; et
al. |
February 14, 2008 |
Water-Soluble Nanoparticles Stabilized with Multi-Functional Group
Ligands and Method of Preparation Thereof
Abstract
Disclosed are water-soluble nanoparticles. The water-soluble
nanoparticles are each surrounded by a multifunctional group ligand
including an adhesive region, a cross linking region, and a
reactive region. In the water-soluble nanoparticles, the
cross-linking region of the multifunctional group ligand is
cross-linked with another cross-linking region of a neighboring
multifunctional group ligand. Furthermore, the present invention
provides a method of producing water-soluble nanoparticles, which
includes (1) synthesizing water-insoluble nanoparticles in an
organic solvent, (2) dissolving the water insoluble nanoparticles
in a first solvent and dissolving water-soluble multifunctional
group ligands in a second solvent, (3) mixing the two solutions
from the step (2) to substitute surfaces of the water-insoluble
nanoparticles with the multifunctional group ligands and dissolving
a mixture in an aqueous solution to conduct a separation process,
and (4) cross-linking the substituted multifunctional group ligands
with each other.
Inventors: |
Cheon; Jin-Woo; (Seoul,
KR) ; Jun; Young-Wook; (Goyang-si, KR) ; Choi;
Jin-Sil; (Daegu, KR) |
Correspondence
Address: |
SHERIDAN ROSS PC
1560 BROADWAY
SUITE 1200
DENVER
CO
80202
US
|
Assignee: |
YONSEI UNIVERSITY
134, Sinchon-dong, Seodaemun-gu
Seoul
KR
120-749
|
Family ID: |
36000248 |
Appl. No.: |
11/571397 |
Filed: |
September 30, 2004 |
PCT Filed: |
September 30, 2004 |
PCT NO: |
PCT/KR04/02509 |
371 Date: |
December 28, 2006 |
Current U.S.
Class: |
424/490 ;
424/130.1; 424/184.1; 424/85.2; 424/85.4; 424/94.64; 514/14.6;
514/16.4; 514/17.7; 514/19.1; 514/19.3; 514/2.1; 514/20.1;
514/44R |
Current CPC
Class: |
Y10S 977/795 20130101;
A61K 49/1839 20130101; A61K 49/1866 20130101; A61K 47/6929
20170801; Y10S 977/773 20130101; A61K 49/1875 20130101; A61K
49/1836 20130101; B82Y 5/00 20130101; Y10S 977/81 20130101; A61P
43/00 20180101; Y10S 977/811 20130101; Y10S 977/896 20130101; A61K
47/6923 20170801; A61P 35/00 20180101 |
Class at
Publication: |
424/490 ;
424/130.1; 424/184.1; 424/085.2; 424/085.4; 424/094.64; 514/012;
514/044 |
International
Class: |
B82B 3/00 20060101
B82B003/00; A61K 31/7105 20060101 A61K031/7105; A61K 31/711
20060101 A61K031/711; A61K 38/16 20060101 A61K038/16; A61K 38/18
20060101 A61K038/18; A61K 38/20 20060101 A61K038/20; A61K 38/21
20060101 A61K038/21; A61K 38/22 20060101 A61K038/22; A61K 38/49
20060101 A61K038/49; A61K 39/00 20060101 A61K039/00; A61K 39/395
20060101 A61K039/395; A61K 9/51 20060101 A61K009/51; A61P 35/00
20060101 A61P035/00; A61P 43/00 20060101 A61P043/00; B32B 9/00
20060101 B32B009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2004 |
KR |
10-2004-0070304 |
Claims
1. Water-soluble nanoparticles, which are each surrounded by a
multifunctional group ligand (L.sub.I-L.sub.II-L.sub.III) including
an adhesive region (L.sub.I), a cross-linking region (L.sub.II),
and a reactive region (L.sub.III), and in which the cross-linking
region of the multifunctional group ligand is cross-linked with
another cross-linking region of a neighboring multifunctional group
ligand.
2. The water-soluble nanoparticles as set forth in claim 1, wherein
each of the nanoparticles includes a metal, a metal chalcogenide, a
magnetic material, a magnetic alloy, a semiconductor material, or a
multicomponent mixed structure, and each of them has a diameter of
1-1000 nm.
3. The water-soluble nanoparticles as set forth in claim 2, wherein
the metal is selected from the group consisting of Pt, Pd, Ag, Cu,
Ru, Rh, Os and Au.
4. The water-soluble nanoparticles as set forth in claim 2, wherein
the metal chalcogenide is selected from the group consisting of
M.sub.xE.sub.y (M=Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Mo, Ru, Rh,
Ag, W, Re, Ta, Zn; E=O, S, Se, 0<x.ltoreq.3, 0<y.ltoreq.5),
BaSr.sub.xTi.sub.1-xO.sub.3, PbZr.sub.xTi.sub.1-xO.sub.3
(0.ltoreq.x.ltoreq.1), and SiO.sub.2.
5. The water-soluble nanoparticles as set forth in claim 2, wherein
the magnetic material is selected from the group consisting of Co,
Mn, Fe, Ni, Gd, MM'.sub.2O.sub.4, M.sub.xO.sub.y (M or M'=Co, Fe,
Ni, Mn, Zn, Gd, Cr, 0<x.ltoreq.3, 0<y.ltoreq.5).
6. The water-soluble nanoparticles as set forth in claim 2, wherein
the magnetic alloy is selected from the group consisting of CoCu,
CoPt, FePt, CoSm, CoAu, CoAg, CoPtAu, CoPtAg, NiFe and NiFeCo.
7. The water-soluble nanoparticles as set forth in claim 2, wherein
the semiconductor material is a first semiconductor material
consisting of an element selected from a group II and an element
selected from a group VI, a second semiconductor material
consisting of an element selected from a group III and an element
selected from a group V, a third semiconductor material consisting
of a group IV, a fourth semiconductor material consisting of an
element selected from the group IV and an element selected from the
group VI, or a fifth semiconductor material consisting of an
element selected from the group V and an element selected from the
group VI.
8. The water-soluble nanoparticles as set forth in claim 2, wherein
the multicomponent mixed structure includes two or more components
selected from the group consisting of the metal, the metal
chalcogenide, the magnetic material, the magnetic alloy, and the
semiconductor according to selected from the group of Pt, Pd, Ag,
Cu, Ru, Rh, Os, and Au, and has a core-shell or bar code shape.
9. The water-soluble nanoparticles as set forth in claim 1, wherein
the adhesive region (L.sub.I) includes a functional group selected
from the group consisting of --COOH, --NH.sub.2, --SH,
--CONH.sub.2, --PO.sub.3H, --PO.sub.4H, --SO.sub.3H, --SO.sub.4H,
and --OH.
10. The water-soluble nanoparticles as set forth in claim 1,
wherein the cross-linking region (L.sub.II) includes a functional
group selected from the group consisting of --SH, --NH.sub.2,
--COOH, --OH, epoxy, -ethylene, and -acetylene.
11. The water-soluble nanoparticles as set forth in claim 1,
wherein the reactive region (L.sub.III) includes a functional group
selected from the group consisting of --SH, --COOH, --NH.sub.2,
--OH, --NR.sub.4.sup.+X.sup.-, -sulfonate, -nitrate, and
phosphonate.
12. The water-soluble nanoparticles as set forth in claim 1,
wherein the active component is selected from the group consisting
of a bioactive component, a polymer, and an inorganic
supporter.
13. The water-soluble nanoparticles as set forth in claim 12,
wherein the bioactive component is selected from the group
consisting of an antigen, an antibody, RNA, DNA, hapten, avidin,
streptavidin, protein A, protein G, lectin, selectin, an anticancer
drug, an antibiotic drug, a hormone, a hormone antagonist,
interleukin, interferon, a growth factor, a tumor necrosis factor,
endotoxin, lymphotoxin, urokinase, streptokinase, a tissue
plasminogen activator, a protease inhibitor, alkyl phosphocholine,
a component indicated by a radioactive isotope, a surfactant, a
cardiovascular pharmaceutical, a gastrointestinal pharmaceutical,
and a neuro pharmaceutical.
14. The water-soluble nanoparticles as set forth in claim 12,
wherein the polymer is selected from the group consisting of
polyphosphazene, polylactide, polylactide-co-glycolide,
polycaprolactone, polyanhydride, polymaleic acid and derivatives
thereof, polyalkylcyanoacrylate, polyhydroxybutylate,
polycarbonate, polyorthoester, polyethylene glycol, poly-L-lycine,
polyglycolide, polymethylmethacrylate, and
polyvinylpyrrolidone.
15. The water-soluble nanoparticles as set forth in claim 12,
wherein the inorganic supporter is selected from the group
consisting of silica (SiO.sub.2), titania (TiO.sub.2), indium tin
oxide (ITO), a carbon material, a semiconductor substrate, and a
metal substrate.
16. The water-soluble nanoparticles as set forth in claim 1,
wherein the multifunctional group ligand is a peptide containing at
least one amino acid having --SH, --COOH, --NH.sub.2, or --OH as a
branched chain.
17. The water-soluble nanoparticles as set forth in claim 16,
wherein the peptide contains any one of amino acid sequences
described in SEQ ID Nos. 1 to 3.
18. The water-soluble nanoparticles as set forth in claim 1,
wherein the multifunctional group ligand is a compound, which
includes --COOH as a functional group of the adhesive region
(L.sub.I), --SH as a functional group of the cross-linking region
(L.sub.II), and --COOH or --SH as a functional group of the
reactive region (L.sub.III).
19. The water-soluble nanoparticles as set forth in claim 18,
wherein the compound is selected from the group consisting of
dimercaptosuccinic acid, dimercaptomaleic acid, and
dimercaptopentadionic acid.
20. The water-soluble nanoparticles as set forth in claim 1,
wherein the multifunctional group ligand is combined with a
biodegradable polymer.
21. The water-soluble nanoparticles as set forth in claim 20,
wherein the biodegradable polymer is selected from the group
consisting of polyphosphazene, polylactide,
polylactide-co-glycolide, polycaprolactone, polyanhydride,
polymaleic acid and derivatives thereof, polyalkylcyanoacrylate,
polyhydroxybutylate, polycarbonate, polyorthoester, polyethylene
glycol, poly-L-lycine, polyglycolide, polymethylmethacrylate, and
polyvinylpyrrolidone.
22. A method of producing water-soluble nanoparticles, comprising:
(1) synthesizing water-insoluble nanoparticles in an organic
solvent; (2) dissolving the water-insoluble nanoparticles in a
first solvent and dissolving water-soluble multifunctional group
ligands in a second solvent; (3) mixing two solutions in the step
(2) to substitute surfaces of the water-insoluble nanoparticles
with the multifunctional group ligands and dissolving a mixture in
an aqueous solution to conduct a separation process; and (4)
cross-linking the substituted multifunctional group ligands with
each other.
23. The method as set forth in claim 22, wherein the
water-insoluble nanoparticles of the step (1) are produced through
a chemical reaction of a nanoparticle precursor in an organic
solvent containing a surface stabilizer.
24. The method as set forth in claim 23, wherein the
water-insoluble nanoparticles are produced according to a process
which comprises adding the nanoparticle precursor to the organic
solvent containing the surface stabilizer at 10-600.degree. C.,
maintaining the resulting solvent under temperature and time
conditions suitable for making the desired water-insoluble
nanoparticles to chemically react the nanoparticle precursor and
thus grow the nanoparticles, and separating and purifying the
nanoparticles.
25. The method as set forth in claim 22, wherein the organic
solvent is selected from the group consisting of a benzene-based
solvent, a hydrocarbon solvent, an ether-based solvent, and a
polymer solvent.
26. The method as set forth in claim 22, wherein the first solvent
in the step (2) is selected from the group consisting of a
benzene-based solvent, a hydrocarbon solvent, an ether-based
solvent, halohydrocarbon, alcohol, a sulfoxide-based solvent, and
an amide-based solvent.
27. The method as set forth in claim 22, wherein the second solvent
in the step (2) is selected from the group consisting of a
benzene-based solvent, a hydrocarbon solvent, an ether-based
solvent, halohydrocarbon, alcohol, a sulfoxide-based solvent, an
amide-based solvent, and water.
Description
TECHNICAL FIELD
[0001] The present invention relates, in general, to water-soluble
nanoparticles and, more particularly, to water-soluble
nanoparticles, which are each surrounded by a multifunctional group
ligand (L.sub.I-L.sub.II-L.sub.III) including an adhesive region
(L.sub.I), a cross-linking region (L.sub.II), and a reactive region
(L.sub.III), and in which the cross-linking region of the
multifunctional group ligand is cross-linked with another
cross-linking region of a neighboring multifunctional group
ligand.
[0002] Furthermore, the present invention pertains to a method of
producing water-soluble nanoparticles, which includes (1)
synthesizing water-insoluble nanoparticles in an organic solvent,
(2) dissolving the water-insoluble nanoparticles in a first solvent
and dissolving water-soluble multifunctional group ligands in a
second solvent, (3) mixing two solutions in the step (2) to
substitute surfaces of the water-insoluble nanoparticles with the
multifunctional group ligands and dissolving a mixture in an
aqueous solution to conduct a separation process, and (4)
cross-linking the substituted multifunctional group ligands with
each other.
BACKGROUND ART
[0003] Used to adjust and control a substance at an atomic or
molecular level, nanotechnology is suitable to create novel
substances and materials, and applied to various fields, such as
electronic, material, communication, mechanical, medical,
agricultural, energy, and environmental fields.
[0004] Currently, development of various types of nanotechnologies
is in progress, and the nanotechnology is usually classified into
the following three categories. The first category relates to a
technology to synthesize ultrafine novel substances and matter
using a nano-material. The second category relates to a technology
to produce a device which assures predetermined functions by
combining or arranging nano-sized materials. The third category
relates to a technology to apply a nanotechnology, which is called
a nano-bio, to bioengineering.
[0005] Particularly, in nano-bio fields, nanoparticles are used to
specifically kill cancer cells, boost an immune reaction, fuse
cells, deliver genes or drugs, conduct diagnosis and the like. In
order to apply the nanoparticles to the above applications, the
nanoparticles must have portions, to which active components are
capable of adhering, and must be stably delivered and dispersed in
vivo, that is, in a water-soluble environment. Many technologies
have lately been developed to satisfy such conditions.
[0006] U.S. Pat. No. 6,274,121 discloses paramagnetic nanoparticles
including metals, such as iron oxides, to which inorganic
materials, having binding sites that are capable of being coupled
with tissue-specific binding substances and diagnostically or
pharmaceutically active materials, adhere.
[0007] U.S. Pat. No. 6,638,494 pertains to paramagnetic
nanoparticles containing metals, such as iron oxides, and discloses
a method of preventing nanoparticles from cohering and
precipitating in the gravity or magnetic fields, in which specific
carboxylic acid adheres to surfaces of the nanoparticles. Examples
of the above carboxylic acid include aliphatic dicarboxylic acid,
such as maleic acid, tartaric acid, and glucaric acid, or aliphatic
polycarboxylic acid, such as citric acid, cyclohexane, and
tricarboxylic acid.
[0008] U.S. Pat. No. 6,649,138 discloses a method of improving the
water-soluble property of nanoparticles, in which a multiply
amphiphilic dispersant layer is formed on surfaces of the
hydrophobic nanoparticles having semiconductor or metal materials.
The multiply amphiphilic dispersant is exemplified by (1) a
hydrophobic backbone having hydrophilic branched chains, (2) a
hydrophilic backbone having hydrophobic branched chains, or (3) a
hydrophobic or hydrophilic backbone simultaneously having
hydrophilic and hydrophobic branched chains.
[0009] U.S. Patent Application No. 2004/0033345 discloses a method
of capsulizing nanoparticles, in which hydrophobic ligand layers
are formed around metals or semiconductors, using micelles to
dissolve the nanoparticles in an aqueous solution. At this time,
the micelles consist of hydrophilic shells and hydrophobic
cores.
[0010] U.S. Patent Application No. 2004/0058457 suggests functional
nanoparticles which are surrounded by monolayers, and in which
bifunctional peptides adhere to the monolayers and various
biopolymers including DNA and RNA are bound to the peptides.
[0011] However, the water-soluble nanoparticles produced according
to the above method, have the following disadvantages. In U.S. Pat.
Nos. 6,274,121, and 6,638,494, and U.S. Patent Application No.
2004/0058457, the nanoparticles are synthesized in aqueous
solution. In such a case, it is difficult to control the sizes of
the nanoparticles, and the synthesized nanoparticles have a
nonuniform size distribution. Furthermore, since they are
synthesized at low temperatures, crystallinities of the
nanoparticles are low and non-stoichiometric compounds are apt to
be generated. Additionally, surfaces of the nanoparticles are
coated with a monomolecular surface stabilizer, but bonding
strengths between the stabilizer and the nanoparticles are not
high, and thus, the nanoparticles are less stable in aqueous
solution. The water-soluble nanoparticles of U.S. Pat. No.
6,649,138 and U.S. Patent Application No. 2004/0033345 are
surrounded by amphiphilic polymers, thus having significantly
increased diameters in comparison with inorganic nanoparticles.
Further, successful application examples of these nanoparticles are
limited to semiconductor nanoparticles.
DISCLOSURE OF THE INVENTION
[0012] Accordingly, an object of the present invention is to
provide water-soluble nanoparticles which are highly stable in
aqueous solution and have low toxicity to living bodies, thereby
being applied to various fields, such as bio diagnosis and
treatment, and electronic materials, and a method of preparation
thereof.
[0013] In order to accomplish the above object, the present
inventors added multifunctional group ligands, each of which
includes (a) an adhesive region bonded to nanoparticles, (b) a
cross-linking region stabilizing the nanoparticles in an aqueous
solution, and (c) a reactive region capable of being bonded to
active components, to the nanoparticles gained from an organic
solvent, thereby producing nanoparticles which are stable in
aqueous solution and are capable of being bonded to various active
components.
[0014] The present invention provides water-soluble nanoparticles,
which are each surrounded by a multifunctional group ligand
including an adhesive region, a cross-linking region, and a
reactive region, and in which the cross-linking region of the
multifunctional group ligand is cross-linked with another
cross-linking region of a neighboring multifunctional group
ligand.
[0015] Furthermore, the present invention provides a method of
producing water-soluble nanoparticles, which includes (1)
synthesizing water-insoluble nanoparticles in an organic solvent,
(2) dissolving the water-insoluble nanoparticles in a first solvent
and dissolving water-soluble multifunctional group ligands in a
second solvent, (3) mixing two solutions in the step (2) to
substitute surfaces of the water-insoluble nanoparticles with the
multifunctional group ligands and dissolving a mixture in an
aqueous solution to conduct a separation process, and (4)
cross-linking the substituted multifunctional group ligands with
each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0017] FIG. 1 illustrates the production of water-soluble
nanoparticles from water-insoluble nanoparticles according to the
present invention;
[0018] FIG. 2 schematically illustrates the water-soluble
nanoparticles according to the present invention;
[0019] FIG. 3 illustrates the production process of water-soluble
iron oxide nanoparticles surrounded by dimercaptosuccinic acid
according to the present invention;
[0020] FIG. 4 illustrates the solubility of iron oxide
nanoparticles, surrounded by an organic surface stabilizer, in an
organic solvent, and the solubility of the water-soluble iron oxide
nanoparticles, surrounded by water-soluble multifunctional group
ligands, in an aqueous solution;
[0021] FIG. 5 illustrates the results of electrophoresis of the
water-soluble iron oxide nanoparticles according to the present
invention;
[0022] FIGS. 6A to 6D are transmission electron microscope (TEM)
images of the water-soluble iron oxide nanoparticles (4, 6, 9, and
12 nm) according to the present invention;
[0023] FIG. 7 illustrates the results of electrophoresis of the
water-soluble core-shell (FePt@Fe.sub.3O.sub.4) nanoparticles
according to the present invention;
[0024] FIG. 8 is a transmission electron microscope (TEM) image of
the water-soluble core-shell (FePt@Fe.sub.3O.sub.4) nanoparticles
according to the present invention; and
[0025] FIG. 9 illustrates the result of electrophoresis of the
water-soluble iron oxide nanoparticles according to the present
invention, which shows that the water-soluble iron oxide
nanoparticles can be bonded to active components.
BEST MODE FOR CARRYING OUT THE INVENTION
[0026] In the specification of the present invention,
"nanoparticles" means particles which each include a metal
material, a metal chalcogenide, a magnetic material, a magnetic
alloy, a semiconductor material, or a multicomponent mixed
structure and each of which has a diameter of 1-1000 nm, and
preferably 2-100 nm.
[0027] In the specification of the present invention,
"water-insoluble nanoparticles" means nanoparticles surrounded by a
hydrophobic surface stabilizer, which may be produced through a
chemical reaction of a nanoparticle precursor in an organic
solvent, containing a typical surface stabilizer, so as to have
excellent crystallinity and desired size, shape, and composition.
The "surface stabilizer" means organic functional molecules capable
of stabilizing a state and a size of the nanoparticle, and
representative examples include a surfactant.
[0028] Regarding "water-soluble nanoparticles" according to the
present invention, a water-soluble multifunctional group ligand
layer is formed instead of the hydrophobic surface stabilizer on
surfaces of the water-insoluble nanoparticles. The multifunctional
group ligands are cross-linked with each other, and thus, the
water-soluble nanoparticles can be stably dissolved and dispersed
in an aqueous solution. In detail, the water-soluble nanoparticles
are surrounded by the multifunctional group ligands, each of which
includes an adhesive region, a cross-linking region, and a reactive
region. The cross-linking regions of the multifunctional group
ligands are cross-linked with other cross-linking regions of
neighboring multifunctional group ligands.
[0029] The water-soluble nanoparticles according to the present
invention may be provided in various forms which depend on the type
of metal, metal chalcogenide, magnetic material, magnetic alloy,
semiconductor material or multicomponent mixed structure, and
multifunctional group ligand.
[0030] Examples of the metal include Pt, Pd, Ag, Cu, Au, Ru, Rh,
and Os, and the metal chalcogenide is exemplified by M.sub.xE.sub.Y
(M=Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Mo, Ru, Rh, Ag, W, Re, Ta,
Zn; E=O, S, Se, 0<x.ltoreq.3, 0<y.ltoreq.5),
BaSr.sub.xTi.sub.1-xO.sub.3, PbZr.sub.xTi.sub.1-xO.sub.3
(0.ltoreq.x.ltoreq.1), and SiO.sub.2. Examples of the magnetic
material include Co, Mn, Fe, Ni, Gd, MM'.sub.2O.sub.4, and
M.sub.xO.sub.y (M or M'=Co, Fe, Ni, Mn, Zn, Gd, Cr,
0<x.ltoreq.3, 0<y.ltoreq.5), and the magnetic alloy is
exemplified by CoCu, CoPt, FePt, CoSm, NiFe, CoAu, CoAg, CoPtAu,
CoPtAg and NiFeCo.
[0031] Furthermore, examples of the semiconductor material may
include a semiconductor material consisting of elements selected
from group II (Zn, Cd, Hg) and elements selected from group VI (O,
S, Se), a semiconductor material consisting of elements selected
from group III (B, Al, Ga, In) and elements selected from group V
(P, As, Sb), a semiconductor material consisting of group IV (Si,
Ge, Pb, Sn), a semiconductor material consisting of elements
selected from group IV (Si, Ge) and elements selected from group VI
(O, S, Se), or a semiconductor material consisting of elements
selected from group V (P, As, Sb, Bi) and elements selected from
group VI (O, S, Se).
[0032] The "multicomponent mixed structure" is a particle including
two or more components selected from the group consisting of metal,
metal chalcogenide, magnetic material, magnetic alloy, and
semiconductor material, and representative examples in shape are a
core-shell and a bar code.
[0033] In the specification of the present invention, the
"multifunctional group ligand (L.sub.I-L.sub.II-L.sub.III)" means a
material including (a) an adhesive region (L.sub.I), (b) a
cross-linking region (L.sub.II), and (c) a reactive region
(L.sub.III). Hereinafter, a detailed description will be given of
the multifunctional group ligand.
[0034] The "adhesive region (L.sub.I)" means a portion of the
multifunctional group ligand which contains a functional group
capable of adhering to nanoparticles, and preferably an end of the
ligand. Accordingly, it is preferable that the adhesive region
include the functional group having a high affinity for a material
constituting the nanoparticles, and the functional group of the
adhesive region may be selected depending on the type of material
constituting the nanoparticles. The adhesive region may include
--COOH, --NH.sub.2, --SH, --CONH.sub.2, --PO.sub.3H, --PO.sub.4H,
--SO.sub.3H, --SO.sub.4H, or --OH as the functional group.
[0035] The "cross-linking region (L.sub.II)" means another portion
of the multifunctional group ligand which includes a functional
group capable of being cross-linked with neighboring
multifunctional group ligands, and preferably the central portion
of the ligand. "Cross-linking" means an intermolecular interaction
between the adjacent multifunctional group ligands. Illustrative,
but non-limiting, examples of the intermolecular interaction
include a hydrophobic interaction, a hydrogen bond, a covalent bond
(e.g. disulfide bond), a van der Waals bond, and an ionic bond.
Since the intermolecular interaction is not limited to the above
examples, the functional group to be cross-linked may be selected
depending on the type of desired intermolecular interaction. The
cross-linking region may include --SH, --NH.sub.2, --COOH, --OH,
-epoxy, -ethylene, or -acetylene as the functional group.
[0036] The "reactive region (L.sub.III)" means another portion of
the multifunctional group ligand which contains a functional group
capable of adhering to an active component, and preferably the
other end positioned opposite to the reactive region. The
functional group of the reactive region depends on the type and
chemical formula of active component (refer to Table 1).
Non-limiting, illustrative examples of the functional groups of the
reactive region include --SH, --COOH, --NH.sub.2, --OH,
--NR.sub.4.sup.+X.sup.-, -sulfonate, -nitrate, or phosphonate.
TABLE-US-00001 TABLE 1 Examples of functional groups of the
reactive region included in the multifunctional group ligand I II
III R--NH.sub.2 R'--COOH R--NHCO--R' R--SH R'--SH R--SS--R R--OH
R'--(epoxy group) R--OCH.sub.2C(OH)CH.sub.2--R' RH--NH.sub.2
R'--(epoxy group) R--NHCH.sub.2C(OH)CH.sub.2--R' R--SH R'--(epoxy
group) R--SCH.sub.2C(OH)CH.sub.2--R' R--NH.sub.2 R'--COH
R--N.dbd.CH--R' R--NH.sub.2 R'--NCO R--NHCONH--R' R--NH.sub.2
R'--NCS R--NHCSNH--R' R--SH R'--COCH.sub.2 R'--COCH.sub.2S--R R--SH
R'--O(C.dbd.O)X R--OCH.sub.2(C.dbd.O)O--R' R--(aziridine group)
R'--SH R--CH.sub.2CH(NH.sub.2)CH.sub.2S--R' R--CH.dbd.CH.sub.2
R'--SH R--CH.sub.2CHS--R' R--OH R'--NCO R'--NHCOO--R R--SH
R'--COCH.sub.2X R--SCH.sub.2CO--R' R--NH.sub.2 R'--CON.sub.3
R--NHCO--R' R--COOH R'--COOH R--(C.dbd.O)O(C.dbd.O)--R' + H.sub.2O
R--SH R'--X R--S--R' R--NH.sub.2 R'CH.sub.2C(NH.sup.2+)OCH.sub.3
R--NHC(NH.sup.2+)CH.sub.2--R' R--OP(O.sup.2-)OH R'--NH.sub.2
R--OP(O.sup.2-)--NH--R' R--CONHNH.sub.2 R'--COH R--CONHN.dbd.CH--R'
R--NH.sub.2 R'--SH R--NHCO(CH.sub.2).sub.2SS--R' (I: the functional
group of the reactive region of the multifunctional group ligand,
II: active components, and III: examples of bonds formed by
reaction of I with II)
[0037] In the present invention, a compound originally containing
the above functional groups may be used as the water-soluble
multifunctional group ligand. Alternatively, a compound which is
modified or produced through a chemical reaction known in the art
so as to include the above functional groups may be used as the
multifunctional group ligand.
[0038] In the water-soluble nanoparticles according to the present
invention, an example of a preferred multifunctional group ligand
is dimercaptosuccinic acid. This is based on the fact that
dimercaptosuccinic acid originally includes an adhesive region, a
cross-linking region, and a reactive region. In other words, --COOH
located at one end of dimercaptosuccinic acid adheres to the
nanoparticle, --SH positioned at the center of dimercaptosuccinic
acid is bonded to neighboring dimercaptosuccinic acid by a
disulfide bond, and --COOH and --SH located at the other end of
dimercaptosuccinic acid are bonded to active components. In
addition to dimercaptosuccinic acid, a compound, which includes
--COOH as the functional group of the adhesive region (L.sub.I),
--SH as the functional group of the cross-linking region
(L.sub.II), and --COOH or --SH as the functional group of the
reactive region (L.sub.III), may be used as the preferred
multifunctional group ligand. Illustrative, but non-limiting
examples of the compound include dimercaptomaleic acid and
dimercaptopentadionic acid.
[0039] In the water-soluble nanoparticles according to the present
invention, another example of a preferred multifunctional group
ligand is peptide. Peptide is an oligomer/polymer consisting of a
few amino acids. Amino acid has --COOH and --NH.sub.2 functional
groups at both ends thereof, and thus, peptide spontaneously
includes an adhesive region and a reactive region. Additionally,
since some amino acids have --SH or --OH as a branched chain,
peptide, which is produced so that the said amino acids are
contained in a cross-linking region, may be used as the
multifunctional group ligand in the present invention.
[0040] In the present invention, the multifunctional group ligand
may be formed in combination with a biodegradable polymer. Examples
of the biodegradable polymer include polyphosphazene, polylactide,
polylactide-co-glycolide, polycaprolactone, polyanhydride,
polymaleic acid and derivatives thereof, polyalkylcyanoacrylate,
polyhydroxybutylate, polycarbonate, polyorthoester, polyethylene
glycol, poly-L-lycine, polyglycolide, polymethylmethacrylate, and
polyvinylpyrrolidone.
[0041] Meanwhile, an "active component", which is to be bonded to
the reactive region of the multifunctional group ligand according
to the present invention, may be selected depending on the
application of the water-soluble nanoparticles according to the
present invention. Examples of the active component may include a
bioactive component, a polymer, or an inorganic supporter.
[0042] Illustrative, but non-limiting, examples of the bioactive
component include tissue-specific binding substances, such as an
antigen, an antibody, RNA, DNA, hapten, avidin, streptavidin,
protein A, protein G, lectin, selectin; and pharmaceutically active
components, such as anticancer drugs, antibiotic drugs, hormones,
hormone antagonists, interleukin, interferon, growth factors, tumor
necrosis factors, endotoxin, lymphotoxin, urokinase, streptokinase,
tissue plasminogen activators, protease inhibitors, alkyl
phosphocholine, surfactants, cardiovascular pharmaceuticals,
gastrointestinal pharmaceuticals, and neuro pharmaceuticals.
[0043] Examples of the polymer include polyphosphazene,
polylactide, polylactide-co-glycolide, polycaprolactone,
polyanhydride, polymaleic acid and derivatives thereof,
polyalkylcyanoacrylate, polyhydroxybutylate, polycarbonate,
polyorthoester, polyethylene glycol, poly-L-lycine, polyglycolide,
polymethylmethacrylate, and polyvinylpyrrolidone.
[0044] Illustrative, but non-limiting examples of the inorganic
supporter include silica (SiO.sub.2), titania (TiO.sub.2), indium
tin oxide (ITO), a carbon material (nanotube, graphite, fullerene
or the like), a semiconductor substrate (Si, GaAs, AlAs or the
like), and a metal substrate (Au, Pt, Ag, Cu or the like).
[0045] A method of producing the water-soluble nanoparticles of the
present invention includes (1) synthesizing water-insoluble
nanoparticles in an organic solvent, (2) dissolving the
water-insoluble nanoparticles in a first solvent and dissolving
water-soluble multifunctional group ligands in a second solvent,
(3) mixing the two solutions of the step (2) to substitute surfaces
of the water-insoluble nanoparticles with the multifunctional group
ligands, and dissolving a mixture in an aqueous solution to conduct
a separation process, and (4) cross-linking the substituted
multifunctional group ligands with each other.
[0046] The step (1) of the method relates to a process of producing
the water-insoluble nanoparticles. The process of producing the
water-insoluble nanoparticles according to the present invention
includes adding a nanoparticle precursor to an organic solvent
containing a surface stabilizer at 10-600.degree. C., maintaining
the resulting solution under temperature and time conditions
suitable to make the desired water-insoluble nanoparticles to
chemically react the nanoparticle precursor and thus grow the
nanoparticles, and separating and purifying the water-insoluble
nanoparticles.
[0047] Illustrative, but non-limiting, examples of the organic
solvent include a benzene-based solvent (e.g. benzene, toluene,
halobenzene or the like), a hydrocarbon solvent (e.g. octane,
nonane, decane or the like), an ether-based solvent (e.g. benzyl
ether, phenyl ether, hydrocarbon ether or the like), and a polymer
solvent.
[0048] In the step (2) of the method, the nanoparticles produced in
the preceding step are dissolved in the first solvent and the
multifunctional group ligand is dissolved in the second solvent.
Examples of the first solvent include a benzene-based solvent (e.g.
benzene, toluene, halobenzene or the like), a hydrocarbon solvent
(e.g. pentane, hexane, nonane, decane or the like), an ether-based
solvent (e.g. benzyl ether, phenyl ether, hydrocarbon ether or the
like), halohydrocarbon (e.g. methylene chloride, methane bromide or
the like), alcohol (e.g. methanol, ethanol or the like), a
sulfoxide-based solvent (e.g. dimethylsulfoxide or the like), and
an amide-based solvent (e.g. dimethylform amide or the like. In
addition to the solvents capable of being used as the first
solvent, water may be used as the second solvent.
[0049] In the step (3) of the method, the two solutions are mixed
with each other. In this step, the organic surface stabilizer of
the water-insoluble nanoparticles is substituted with the
water-soluble multifunctional group ligand (refer to FIG. 1). The
nanoparticles having the water-soluble multifunctional group ligand
substituted as described above can be separated using a typical
method known in the art. Usually, since the water-soluble
nanoparticles are generated as a precipitate, it is preferable to
conduct the separation process using a centrifuge or by filtration.
After the separation process, it is preferable to control the pH to
5 to 10 through a titration process so as to obtain the stably
dispersed water-soluble nanoparticles.
[0050] In the step (4) of the method, the multifunctional group
ligands are cross-linked with each other through some chemical
reactions, thereby stabilizing the water-soluble nanoparticles.
Illustrative, but non-limiting, examples of the chemical reaction
for the cross-linking include an oxidation reaction (e.g. disulfide
bond) and a reduction reaction, a cross-linking reaction using a
molecule connector, and a hydrogen bond. The nanoparticles
stabilized by the cross-linking are dispersed well under conditions
of pH of 5 to 10 and a salt concentration of about 1 M or less
without aggregation.
[0051] A better understanding of the present invention may be
obtained through the following examples which are set forth to
illustrate, but are not to be construed as the limit of, the
present invention.
EXAMPLE 1
[0052] Production of Iron Oxide Nanoparticles Having Various
Sizes
[0053] 4 nm iron oxide nanoparticles were synthesized by thermal
decomposition of Iron triacetyl acetonate (Aldrich) in a
phenylether solvent, which contains 0.3M lauric acid and 0.3M
lauryl amine, at 260.degree. C. for 1 hour. To synthesize 6 nm iron
oxide nanoparticles, it had the same synthesis procedure as that of
the 4 nm iron oxide nanoparticles except that benzyl ether was used
as a solvent and a reaction temperature was 290.degree. C. To
produce 9 nm iron oxide nanoparticles, a benzyl ether solution,
which contained 0.1 M lauric acid, 0.1 M lauryl amine, 8 mg/ml of 6
nm iron oxide nanoparticles, and iron triacetyl acetonate, was
heated at 290.degree. C. for 1 hour. The synthesis procedure of the
12 nm iron oxide nanoparticles was the same as that of the 9 nm
iron oxide nanoparticles except that the 9 nm iron oxide
nanoparticles were put in a solution in a concentration of 8
mg/ml.
EXAMPLE 2
[0054] Production of Water-Soluble Iron Oxide Nanoparticles
[0055] 5 mg of the iron oxide nanoparticles produced in example 1
were dissolved in 1 ml of toluene. Then 0.5 ml of methanol, in
which 20 mg of 2,3-mercaptosuccinic acid was dissolved, was added
to the above toluene solution (refer to FIG. 3). After about 24
hours, a dark brown precipitate was formed. The precipitate was
centrifuged at room temperature at 2000 rpm for 5 min, and
dispersed in 1 ml of deionized water. An air bubbling process was
conducted for 5 min to achieve a disulfide bond of
2,3-mercaptosuccinic acid.
EXAMPLE 3
[0056] Evaluation of Stability of Water-Soluble Iron Oxide
Nanoparticles in an Aqueous Solution
[0057] a. Analysis of Solubility of Water-Soluble Iron Oxide
Nanoparticles
[0058] The water-insoluble iron oxide nanoparticles produced in
example 1 were dissolved in chloromethane, followed by the addition
of water, whereas the water-soluble iron oxide nanoparticles
produced in example 2 were dissolved in water, followed by the
addition of chloromethane. Thereafter, a solubility variance caused
by a surface substitution of the nanoparticles was analyzed.
[0059] From FIG. 4, it was confirmed that a multifunctional group
ligand (2,3-dimercaptosuccinic acid) was substituted with an
organic surface stabilizer to convert water-insoluble nanoparticles
into water-soluble nanoparticles. Additionally, it was confirmed
through observation with the naked eyes that precipitation or
aggregation did not occur, and thus, it can be seen that the
water-soluble iron oxide nanoparticles are dispersed well in an
aqueous solution.
[0060] b. Analysis through Electrophoresis
[0061] 10 .mu.l of solution containing water-soluble iron oxide
nanoparticles in a concentration of about 1 mg/ml was loaded in 1%
agarose gel, and was subjected to an electrophoresis in a 1.times.
TBE (tris-borate-edta) buffer solution while a voltage of 5 V/cm
was applied to the resulting solution for 30 min.
[0062] As shown in FIG. 5, water-soluble iron oxide nanoparticles
moved through the gel since they were smaller than cavities formed
in the agarose gel. Furthermore, a narrow band was formed on the
gel, and thus, it can be seen that the water-soluble iron oxide
nanoparticles were consistent in size and did not aggregate.
Meanwhile, mobility was reduced in accordance with an increase in
the size of the nanoparticles, which means that the water-soluble
iron oxide nanoparticles were consistent in size and did not
aggregate. Through the above results, it can be seen that the
water-soluble iron oxide nanoparticles were dispersed in an aqueous
solution, were consistent in size, and did not aggregate.
[0063] c. Analysis Using a Transmission Electron Microscope
(TEM)
[0064] 20 .mu.l of solution containing water-soluble iron oxide
nanoparticles were dropped on a TEM grid (Ted Pella Inc.) coated
with a carbon film, dried for about 30 min, and observed using an
electron microscope (EF-TEM, Zeiss, acceleration voltage 100
kV).
[0065] As shown in FIG. 6 the water-soluble iron oxide
nanoparticles consistent in size were formed.
EXAMPLE 4
[0066] Production of Core-Shell (FePt@Fe.sub.3O.sub.4)
Nanoparticles
[0067] 0.5 mmol Pt acetylacetonate was dissolved in 10 ml of
benzylether, and heated to 100.degree. C. 4 mmol oleic acid, 1.5
mmol Fe(CO).sub.5, and 4 mmol oleyl amine were added to the
resulting benzylether, heated to 240.degree. C., and maintained at
that temperature for 1 hour to conduct a reaction. At this time,
Fe(CO).sub.5 was decomposed. Subsequently, the resulting solution
was heated to 300.degree. C. and then maintained at that
temperature for 1 hour. After the completion of the reaction, air
was injected for 5 min to produce the core-shell
(FePt@Fe.sub.3O.sub.4) nanoparticles.
EXAMPLE 5
[0068] Production of Water-Soluble Core-Shell Nanoparticles
[0069] The water-soluble core-shell nanoparticles were produced by
the same procedure as example 2 except that the core-shell
nanoparticles produced through example 4 were used.
EXAMPLE 6
[0070] Evaluation of Stability of Water-Soluble Core-Shell
Nanoparticles in an Aqueous Solution
[0071] The stability of the water-soluble core-shell nanoparticles
produced through example 5 in an aqueous solution was evaluated
according to the same procedure as example 3 (refer to FIGS. 7 and
8).
EXAMPLE 7
[0072] Production of Water-Soluble Iron Oxide Nanoparticles Using
Peptide as a Multifunctional Group Ligand
[0073] The water-soluble iron oxide nanoparticles were produced
through the same procedure of example 2 except that the following
peptide was used instead of dimercaptosuccinic acid. TABLE-US-00002
(1) GSE SGG SG(Cha) CC(Cha) CDD - SEQ ID No.: 1 (2) GRR SHG (Cha)CC
(Cha)CD D - SEQ ID No.: 2 (3) GKK HGH Y(Cha)C C(Cha)D CD - SEQ ID
No.: 3 *Cha = cyclohexylalanine
[0074] Surfaces of the nanoparticles were substituted with peptide
to produce nanoparticles that were stable in an aqueous solution.
In peptide, a CDD or DCD portion containing --COOH acts as an
adhesive region, a CC portion containing --SH acts as a
cross-linking region, and the remaining portion acts as a reactive
region.
EXAMPLE 8
[0075] Production of Water-Soluble Iron Oxide Nanoparticles
Combined with a Tie2 Receptor Antibody as an Active Component
[0076] 0.2 mg of tie2 receptor antibody was dissolved in 100 .mu.l
of 10 mM PBS (phosphate buffered saline, pH 7.2), and reacted with
20 .mu.g of sulfo-SMCC (purchased from Pierce Inc.) for 30 min.
Subsequently, the antibody combined with the sulfo-SMCC was
separated through a gel filtration process (Sephadex G-25). The
separated antibody reacted with 0.2 mg of water-soluble iron oxide
nanoparticles produced through example 2 for 12 hours, and
water-soluble iron oxide nanoparticles combined with the tie2
receptor antibody were separated using a gel filtration column
(Sephacryl S200, S400).
EXAMPLE 9
[0077] Confirmation of Combination of Water-Soluble Iron Oxide
Nanoparticles with a Tie2 Receptor Antibody
[0078] The product of example 8 was subjected to an electrophoresis
according to the same procedure as example 3, and the results are
shown in FIG. 9.
[0079] FIG. 9 illustrates that a bioactive component (tie2 receptor
antibody) can be bonded to a reactive region of the water-soluble
nanoparticle. From the electrophoresis results, it can be seen that
the iron oxide nanoparticle combined with the antibody has low
movement during electrophoresis, which is similar to the results of
a protein dyeing. Accordingly, it can be seen that the iron oxide
nanoparticle is combined with the antibody.
INDUSTRIAL APPLICABILITY
[0080] Water-soluble nanoparticles according to the present
invention are consistent in size, and are stable especially in
aqueous solution. Accordingly, the nanoparticles employing various
active components can be applied to composite material, electronic
material, bio diagnosis, and treatment.
* * * * *