WO2008048074A1

WO2008048074A1 - Use of core-shell gold nanoparticle which contains magnetic nanoparticles for mri t2 contrast agent, cancer diagnostic and therapy

Info

Publication number: WO2008048074A1
Application number: PCT/KR2007/005154
Authority: WO
Inventors: Taeghwan Hyeon; Jae Yoon Kim; Myung-Haing Cho; Seong Keun Kim; Junghee Lee
Original assignee: Seoul National University Industry Foundation
Priority date: 2006-10-20
Filing date: 2007-10-19
Publication date: 2008-04-24
Also published as: KR20080035926A

Abstract

The present invention relates to the use of magnetic gold nanoshells consisted of gold nanoshells embedded with magnetic nanoparticles and spherical silica cores for use in MRI T2 contrast agent, cancer diagnosis and cancer therapy. More particularly, the present invention is directed to the use of an MRI T2 contrast agent using the magnetic properties of the magnetic nanoparticles embedded with the gold nanoshell, a cancer diagnostic agent for treating cancer using the cancer binding properties of target-specific ligands bonded to the surface of the magnetic gold nanoparticles and a therapeutic agent for treating cancer using the heat released form the gold nanoshell absorbed from the energy of near infrared ray range electromagnetic pulses to destroy the cancer cells, and methods for the diagnosis and treatment of cancer using the magnetic gold nanoparticles.

Description

[DESCRIPTION] [Invention Tit Ie]

USE OF CORE-SHELL GOLD NANOPARTICLE WHICH CONTAINS MAGNETIC NANOPARTICLES FOR MRI T2 CONTRAST AGENT, CANCER DIAGNOSTIC AND THERAPY [Technical Field]

<i> The present invention relates to the use of magnetic gold nanoshells consisted of gold nanoshells embedded with magnetic nanoparticles and spherical silica cores for use in MRI T2 contrast agent, cancer diagnosis and cancer therapy. More particularly, the present invention is directed to the use of an MRI T2 contrast agent using the magnetic properties of the magnetic nanoparticles embedded with the gold nanoshell, a cancer diagnostic agent for treating cancer using the cancer binding properties of target- specific ligands bonded to the surface of the magnetic gold nanoparticles and a therapeutic agent for treating cancer using the heat released form the gold nanoshell absorbed from the energy of near infrared ray range electromagnetic pulses to destroy the cancer cells, and methods for the diagnosis and treatment of cancer using the magnetic gold nanoparticles. [Background Art]

<2> The term "magnetic resonance imaging (MRI)" in the present invention is a method for obtaining biochemical information within the body through images using the spin relaxing state of the hydrogen atom within a magnetic field. Further, the nanoparticle refers to a particle with at least one dimension less than lOOnm (nm, 1 billionth of a meter sized material has intermediate properties of atom and bulk material by size).

<3> Furthermore, the term "relaxation" of the present application refers to a process by which nuclear magnetization in a non-equilibrium state returns to equilibrium of net magnetization. Relaxation combines two different mechanisms, which are longitudinal relaxation and transverse relaxation . Longitudinal relaxation due to energy exchange between the spins and the surrounding lattice (spin-lattice relaxation), re-establishing thermal equilibrium. As spin returns from a high energy state back to a low energy state, RF energy is released back to the surrounding lattice. The longitudinal relaxation time, TI, is the decay constant for z component of the nuclear spin magnetization, M_z. The magnetization will recover to 63% of its equilibrium value after time Tl.

<4> Transverse relaxation results from spins getting out of phase. As spins move together, their magnetic fields interact (spin-spin interaction), slightly modifying their precession rate. These interactions are temporary and random. Transverse magnetization decay is described by an exponential curve. The transverse relaxation time T2 is the decay constant for the component of the nuclear spin magnetization perpendicular to the external magnetic field, M_xy. After time T2, the transverse magnetization drops to 37% of its original magnitude.

<5> Furthermore, the term "contrast agent" of the present invention refers to a compound used to improve shadow contrast of internal bodily structures in MRI examination, which is classified as Tl and T2 contrast agents. Tl contrast agents are comprised of the metal ion complex gadolium- based agent (Gd-DTPA) or manganese-based agent (Mn-DTPA) etc. which increase the shadow contrast between tissues during longitudinal relaxation. T2 contrast agents utilize a magnetic iron oxide agent, e.g. Feridex etc., as the materials which increase the shadow contrast between tissues during transverse relaxation.

<6> The term "r2 relaxivity" of the present invention refers to the value of the degree of decrease in T2. Depending on their size, inorganic nanoparticles, such as magnetic nanoparticles embedded within the magnetic gold nanoparticle of the present invention, gold nanoshells or semiconductor nanoparticles possess multifarious optical and magnetic qualities, thus the synthesis of these materials are being researched widely.

<7> Furthermore, recently there has been rapid progress in the venture for applying the unique characteristics of these small sized nanoparticles in the biomedical field for diagnosis, imaging, therapy, drug delivery etc.. Said nanoparticles are more importantly used for applications in research pertaining to early stage diagnosis of cancerous cells and appropriate treatment thereof.

<8> Because of the higher possibility to successfully treat cancer at an early stage, the early diagnosis of cancer cells and an appropriate treatment thereof is most important. For early diagnosis of cancer cells, it is essential to diagnose the cancer cells during the incipient stages of differentiation. Because the nanoparticles are to be used in the early diagnosis of cancer, they can be considered to play a primary role. <9> By using the nanoparticles, dependent on its size, it is possible to accumulate at the cancer cell and bind target-specific ligands to the cancer cell for diagnosis at an early stage. Metal oxide nanoparticles which possess paramagnetic characteristics are already being used commercially as MRI T2 contrast agents.

<io> Nanomaterials are not only used for diagnostic purposes and are foreseen in the future to play a primary role in the treatment of cancer as well. Recently, for example, there has been much reported research on noninvasive heat therapy methods. Professor Halas and Professor West of Rice University research team synthesized a gold nanoshell for cancer cell necrosis using heat therapy.

<π> Based on the ratio of the silica nanoparticle core radius and exterior gold nanoshell thickness, the light absorption wavelength can be adjusted from visible light range to near infrared (NIR) range. Professor Halas and Professor West of Rice University research team synthesized a very large gold nanoshell of NIR absorption range, and after bonding a specific antibody to the surface of the gold nanoshell, a NIR continuous wave (CW) laser was administered for reaction of said antibody with the cancer cell.

<i2> By converting NIR light absorbed by the gold nanoshell to heat, the cancer cell was effectively destroyed. Because NIR range light of 800 nm to 1,200 nm is absorbed at a minimum by biological tissue, compared to visible light, NIR range light can reach deep tissue. Therefore, incision area is minimized and by applying NIR range light, the desired heat therapy effect can be achieved. In addition to nanoshells, there have also been research conducted using nanorods which have high light absorption sections, or single walled carbon nanotubes (SWCNT) for heat therapy on cancer cells.

<i3> The aforementioned results of the research is the basis for the simultaneous use of separate nanomaterials bound together as one multifunctional nanomaterial for effective cancer cell diagnosis and therapy. Nanomaterials which are able to simultaneously be used for diagnosis using the especially widely used MRI, and non-invasive heat therapy using NIR can become a good example. Therefore, recently, similar research has been conducted for the novel development of multifunctional nanomaterials for medical use. [Disclosure] [Technical Problem]

<i4> Accordingly, the primary object of the present invention is to provide a use of magnetic gold nanoshell as a T2 contrast agent for magnetic resonance imaging. Through this, the present invention offers a method for obtaining clearer magnetic resonance imaging compared to the conventional techniques.

<i5> Another object of the present invention is to provide a use of said magnetic gold nanoshell as a diagnostic agent for cancer diagnosis. By utilizing the contrasting characteristics of said particle the present invention offers an effective method for cancer diagnosis.

<i6> Yet another objective of the present invention is to offer a use of a cancer therapeutic agent and method for treating cancer using the high near infrared ray (NIR) absorption of the magnetic gold nanoshell (Mag-GNS) of said nanoparticles. In other words, the present invention provides a method for early stage diagnosis using target-specific ligands on the surface of said magnetic gold nanoshell to selectively accumulate the magnetic gold nanoshells on the cancer cell thereby achieving early stage diagnosis of the cancer cells using MRI, and selectively destroying the diagnosed cancer cells by administering NIR range laser to said cancer cells. [Technical Solution]

<i7> The aforementioned primary object of the present invention can be achieved by providing an MRI T2 contrast agent comprising a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target-specific ligands bound to said polyalkylene glycols.

<i8> The diameter of the silica core of said magnetic gold nanoparticle is preferably 50nm to 500nm, and most preferably lOOnm to 200nm. Further, the thickness of the magnetic gold nanoshell of said magnetic gold nanoparticle is preferably 5nm to 50nm and most preferably lOnm to 20nm. Fig. 5 shows a field-dependent magnetization curve of the magnetic gold nanoshells of the present invention.

<i9> The magnetic nanoparticles, which can be embedded within the gold nanoshell of said magnetic gold nanoparticle, is one or more nanoparticles selected from the group consisting of magnetite (FeSO₄), maghemite(gamma-

Fe₃CU) , cobalt ferrite (CoFe2θ₄), manganese oxide (MnO), manganese ferrite(MnFe2θ4), Fe-Pt alloy, Co-Pt alloy, and cobalt(Co).

<20> The diameter of magnetic nanoparticles which can be embedded within the gold nanoshell of said magnetic nanoparticle is preferably 2nm to 30nm, and more preferably 2nm to 20nm.

<2i> The target-specific ligands fo the present invention are used to bind specifically with cancer cells. The unique binding capability of the target specific ligands with cancer cells is used in the present invention. The polyalkylene glycols of the present invention make said gold nanoparticles biocompatible ,and the magnetic nanoparticles which are embedded within the gold nanoshell are used for MRI T2 contrasting agents. Fig. 6 shows T2- weighted images dependent on the density of the magnetic nanoshells of the present invention. Fig. 9 shows selective magnetic resonance images of cancer cells using target-specific magnetic gold nanoparticles of the present invention.

<22> Another object of the present invention can be achieved by applying a cancer diagnostic agent comprising: a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and said target-specific ligands label cancer cells by binding specifically to said cancer cells and react with the irradiation of external electromagnetic waves.

<23> Cancers can be diagnosed by binding said nanoparticles with cancer eel Is.The target-specific ligand used in the present invention is one selected from the group consisting of cancer targeting antibodies such as antϊ-RER2/neu, , folate, aptamer, and TAT peptide.

<24> Yet another object of the present invention can be achieved by providing a cancer therapeutic agent for destroying cancer cells via heat generated by the absorption of pulses of near infrared electromagnetic waves comprising: a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target specific ligands bonded to said polyalkylene glycols.

<25> The gold nanoshell absorbs laser pulses of near infrared ray range, and thus by converting to heat, effectively destroys the cancer cell. Fig. 4 shows a curve for the absorption of vis-NIR by the magnetic gold nanoparticle of the present invention.

<26> The wavelength of the laser pulse delivered to said magnetic gold nanoshell is preferably 600nm to l,500nm, and most preferably 700nm to 900nm. The pulse width of the laser pulse delivered to said magnetic gold nanoshell is preferably 1Ofs to 200ps, and most preferably 1Ofs to 50ps.

<27> The intensity of the laser pulse delivered to said magnetic gold nanoshell is preferably lmW/cm² to 1,00OmW/cm² , and most preferably 1OmW/ cm² to 20OmW/ cm² . <28> The frequency of the laser pulse delivered to said magnetic gold nanoshell is 0.1 kHz to 1 Mhz (1,000 kHz), and most preferably 0.1 kHz to 10 kHz. <29> The duration of delivery of laser pulse to said magnetic gold nanoshell is preferably 1 second to 10 hours, more preferably 1 second to 10 minutes, and most preferably 1 second to 60 seconds.

[Advantageous Effects] <3i> According to the present invention, the magnetic gold nanopart icles are multifunctional nanomaterials used for MRI T2 contrast agents, MRI diagnosis of cancer cells and hyperthermia using a NIR laser, and with simultaneous cancer diagnosis and therapy functionality great efficiency can be expected. When simultaneously using laser pulses, cancer cells can be destroyed in rapid time.

[Description of Drawings] <32> Fig. 1 shows the stepwise process of synthesis according to the present invention. <33> Fig. 2 shows TEM images of the intermediate and final product corresponding to each synthesis process of the present invention. <34> Fig. 3 is an image of the magnetic gold nanopart icles in a water dispersed state according to the present invention. <35> Fig. 4 shows a curve of the visible light near infrared ray (Vis-NIR) absorption of the magnetic gold particle according to the present invention. <36> Fig. 5 shows a curve of the field-dependant magnetization of the magnetic gold nanopart icle according to the present invention. <37> Fig. 6 shows T2 images dependant on the concentration of the magnetic gold nanopart icle according to the present invention. <38> Fig. 7 is an illustrative image of the target-specific magnetic gold nanopart icle after reformation of the surface of said magnetic gold nanoparticle, according to the present invention. <39> Fig. 8 shows the r2 relaxivity dependent on the concentration of the magnetic gold nanoparticle according to the present invention. <40> Fig. 9 shows selective magnetic resonance images of cancer cells using target specific magnetic gold nanoparticles according to the present invention. <4i> Fig. 10 shows the selective destruction of cancer cells, dependent on the intensity of the administered laser, by using the target-specific magnetic gold nanoparticles according to the present invention. <42> Fig. 11 shows enlarged images of the cancer cells destroyed by using the target-specific magnetic gold nanoparticles according to the present invention. [Best Mode]

<43> Hereinafter, the present invention will be described in greater detail with reference to the following examples. The examples are given only for illustration of the present invention and not to be limiting the present invention.

<44> The synthesis of the magnetic nanoparticle will be largely separated into two steps. First, the process for binding iron oxide nanoparticles on the surface of the silica sphere, and secondly, a process for growing the gold nanoshell on the surface of silica core to which said iron oxide nanoparticles are bonded.

<45> The method for binding FesC^ to the silica core was carried out using the same techniques as reported in our past paper (Angew. Chem. Int. Ed., 2006, 45, 4789). The process for growing the gold nanoshell on Si(VFe₃O₄ is identical to existing reported methods for growing gold nanoshell to the surface of silica spheres (Langmui , 2002, 18, 524).

<46>

<47> Example 1: Introduction of poly ethylene glycol (PEG) to the surface of magnetic gold nanoshell (Mag-GNS)

<48> In order to bind poly ethylene glycol (PEG) to the surface of the Mag-GNS, the particles were placed in water with PEG-SH (MW= 5,000, 20 μM) and stirred for 2 hours, and were then removed from the remaining PEG-SH reaction solution using centrifugal separation. The PEG bound Mag-GNS was then re-dispersed in de-ionized distilled water.

<49>

<50> Example 2 : Binding of Mag-GNS wi th ant i body (Mag-GNS-AbHER2_/.πe_< )

<5i> Ortho-pyr idyl-disul f ide-n-hydroxysuccinimide polyethylene glycol (OPSS-PEG-NHS, MW=2 , 000) was used to tether the ant ibodi es to the surface of Mag-GNS. OPSS-PEG-NHS (16mg) was dissolved in NaHC03 (100 mM, pH 8.5, 24 mL) , re-dispersed in ant i-WER2/neu (160 μg). At this conditions, the concentration of the polymer was in excess to the amount of anti- WR2/neu used. The reaction was progressed overnight at a temperature of 4 °C . Unbound antibodies were removed by dialysis. For simple targeting of the matter, antibodies with attached PEG were tethered to the surface of Mag-GNS via an hour reaction. After binding the antibodies, the surface was further changed after reaction for an hour with PEG-thiol (MW=5,000, 2 μM, 8mL) to increase biocompatibility and prevent nonselective adsorption.

<52>

<53> Example 3 : Cell culture in the presence of Mag-GNS-AbHER2//7«/

<54> Two types of cell lines, SKBR3 (human breast cancer cell line) and H520 (human lung cancer cell line), were cultivated in RPMI-1640 culture medium (Hyclone) containing 10% FBS (Terra Cell) at 37^°C and under 5% CO₂ . The cells were cultivated in a T-75 flask (Nalge Nunc International) for target-specific magnetic resonance imaging. Bacteria was cultivated together with the Mag-GNS-Ab_HER2_//7_eϋ solution for 4 hours at 37^°C . After cultivation, the cells were washed in PBS buffer solution, collected, and then separated by centrifugation at l,500rpm. For target-specific near infrared ray photothermal therapy, the cells were separated by Trypsin and re-attached to a 2-well Lab-Tek glass slide (Nalge Nunc International) and grown. The cells were then cultivated together with GNS-Ab_HER2_/Λe_£/ solution for an hour at 37^°C.

After cultivation, the cells were washed with PBS buffer solution and exposed to near infrared laser at various strengths.

<55>

<56> Example 4 : Magnetic resonance imaging of cancer cells in vitro <57> After Mag-GNS with attached PEG was dispersed in distilled water and the cells were cultured together with Mag-GNS-AbHER2_/Λeu inorder to measure the r2 relaxivity, the cultured cells were tested with a full body MRI scanner (Philips, Achieva ver. 1.2, Philips Medical Systems, Best, The Netherlands) operating at 3.0T; change in amplitude, 80 mT/m; maximum rate of change of output voltage, 200ms/s. To measure the r2, 10 different echo times were used in a multislice turbo spin-echo sequence (TR/TE = 5,000/20, 40, 80, 100, 120, 140, 160, 180, 200 ms, in-plane resolution = 200 200mm² , slice thickness = 500 mm) and the spin-spin relaxation times were measured. For the images, the T2 values were calculated using the Mat lap program via the Levenberg-Margardt method. Each T2 ROIs (200 300 pixel) signal strength of each concentration was measured and used to calculate the r2 relaxivity. Fig. 8 shows the r2 relaxivity dependent on the concentrations of the gold nanoparticles of the present invention, and Fig. 9 shows selective magnetic resonance images of a cancer cell using the target-specific magnetic gold nanoparticles of the present invention.

<58>

<59> Example 5 : In vitro near infrared ray photothermal therapy <60> For the photothermal therapy a typical titanium-sapphire laser was used. The basic pulse of the laser was set at a center peak of 800nm. The width of said pulse was 13Ofs. This femtosecond laser was operated with a pulse frequency of 1 kHz. Since the energy stability was within 1%, high intensity profile of light was provided so as to interact equally with targets.

<6i> A laser of various strengths with 800nm wavelength and lmm diameter size was delivered to the cells for 10 seconds. In order to measure the survival rate of the cells, said cells were dyed for 10 minutes using 0.4% of trypan blue after administering near infrared ray. At this point any dead cells were dyed blue. Fig. 11 shows images of the cancer cells destroyed by the target specific magnetic gold nanoparticles of the present invention.

Claims

[CLAIMS]

[Claim 1]

<63> An MRI T2 contrast agent comprising: a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target specific ligands bonded to said polyalkylene glycols.

[Claim 2]

<64> The MRI T2 contrast agent according to claim 1, wherein said magnetic nanoparticle is one or more nanoparticles selected from the group consisting of magnetite (Fe₃O₄), maghemite(gamma-Fe₃θ4), cobalt ferrite (CoFe₂O₄), manganese oxide (MnO), manganese ferrite(MnFe₂O₄) , Fe-Pt alloy, Co-Pt alloy and cobalt (Co).

[Claim 3]

<65> The MRI T2 contrast agent according to claim 1, wherein said target- specific ligand is one selected from the group consisting of anti-HER2/yrøy, folate, aptamer and TAT peptide.

[Claim 4]

<66> The MRI T2 contrast agent according to claim 1, wherein the diameter of said silica core is between 50nm and 500nm.

[Claim 5]

<67> The MRI T2 contrast agent according to claim 1, wherein the diameter of said gold nanoshell is between 50nm and 500nm.

[Claim 6]

<68> The MRI T2 contrast agent according to claim 1, wherein the diameter of said magnetic nanoparticle is between 2nm and 30nm.

[Claim 7]

<69> A cancer diagnostic agent comprising: a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target specific ligands bound to said polyalkylene glycols, wherein said target-specific ligands label cancer cells by binding selectively to said cancer cells and react with the irradiation of external electromagnetic waves.

[Claim 8]

<70> The cancer diagnostic agent according to claim 7, wherein said magnetic nanoparticle is one or more nanoparticles selected from the group consisting of magnetite (Fe3θ₄), maghemite(gamma-Fe3θ₄) , cobalt ferrite

(CoFe₂O₄), manganese oxide (MnO), manganese ferrUe(MnFe₂O₄) , Fe-Pt alloy, Co-

Pt alloy and cobalt (Co).

[Claim 9]

<7i> The cancer diagnostic agent according to claim 7, wherein said target specific ligand is one ligand selected from the group consisting of anti- WR2/neu, folate, aptamer and TAT peptide.

[Claim 10]

<72> The cancer diagnostic agent according to claim 7, wherein the diameter of said silica core is between 50nm and 500nm.

[Claim 11]

<73> The cancer diagnostic agent according to claim 7, wherein the diameter of said gold nanoshell is between 50nm and 500nm.

[Claim 12]

<74> The cancer diagnostic agent according to claim 7, wherein the diameter of said magnetic nanoparticle is between 2nm and 30nm.

[Claim 13]

<75> A cancer therapeutic agent by destroying cancer cells via heat generated by the absorption of pulses of near infrared electromagnetic waves comprising: a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target specific ligands bonded to said polyalkylene glycols.

[Claim 14]

<76> The cancer therapeutic agent according to claim 13, wherein said nanoparticle is one or more nanoparticles selected from the group consisting of magnetite (Fe₃O₄), maghemite(gamma-Fe3θ₄), cobalt ferrite (CoFe₂O₄), manganese oxide (MnO), manganese ferriIe(MnFe₂O₄), Fe-Pt alloy, Co-Pt alloy and cobalt (Co).

[Claim 15]

<77> The cancer therapeutic agent according to claim 13, wherein said target specific ligand is one selected from the group consisting of anti- WR2/neu, folate, aptamer and TAT peptide.

[Claim 16]

<78> The cancer therapeutic agent according to claim 13, wherein the diameter of said silica core is between 50nm and 500nm.

[Claim 17]

<79> The cancer therapeutic agent according to claim 13, wherein the diameter of said gold outer shell is between 50nm and 500nm.

[Claim 18]

<80> The cancer therapeutic agent according to claim 13, wherein the diameter of said magnetic nanoparticle is between 2nm and 30nm.

[Claim 19]

<8i> A method for cancer diagnosis comprising :

<82> administering cancer diagnostic agent into the human body, wherein said diagnostic agent comprises a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target-specific ligands bonded to said polyalkylene glycols so as label cancer cells by binding selectively to said cancer cells and reacting with the irradiation of external electromagnetic waves; bind said cancer diagnostic agent with said cancer cell; and obtain magnetic resonance images using MRI.

[Claim 20]

<83> The method for cancer diagnosis according to claim 19, wherein said magnetic nanoparticle is one or more nanoparticles selected from the group consisting of magnetite (Fe_SO₄), maghemite(gamma-Fe3θ₄) , cobalt ferrite

(CoFe₂O₄), manganese oxide (MnO), manganese ferrite(MnFe₂O₄) , Fe-Pt alloy, Co-

Pt alloy and cobalt (Co).

[Claim 21]

<84> The method for cancer diagnosis according to claim 19, wherein said target specific ligand is one ligand selected from the group consisting of anti-HER2//?«/, folate, aptamer and TAT peptide.

[Claim 22]

<85> The method for cancer diagnosis according to claim 19, wherein the diameter of said silica core is between 50nm and 500nm.

[Claim 23]

<86> The method for cancer diagnosis according to claim 19, wherein diameter of said outer shell is between 50nm to 500nm.

[Claim 24]

<87> The method for cancer diagnosis according to claim 19, wherein the diameter of said magnetic nanoparticle is between 2nm and 30nm.

[Claim 25]

<88> A method for cancer therapy comprising:

<89> administering cancer therapeutic agent into the human body, wherein said cancer therapeutic agent comprises a silica core, a magnetic gold nanoparticle composed of a gold nanoshell structure embedded with magnetic nanoparticles with polyalkylene glycols bonded to the surface of said nanoparticle, and target specific ligands bonded to said polyalkylene glycols so as to destroy cancer cells via heat generated by the absorption of pulses of near infrared electromagnetic waves; bind said cancer therapeutic agent to cancer cell; and deliver a near infrared ray range electromagnetic wave pulse to the bound cancer cell.

[Claim 26]

<90> The method for cancer therapy according to claim 25, wherein said magnetic nanoparticle may be one or more nanoparticles selected from the group consisting of magnetite (Fe₃O₄), maghemite(gamma-Fe3θ₄) , cobalt ferrite

Pt alloy and cobalt (Co).

[Claim 27]

<9i> The method for cancer therapy according to claim 25, wherein said target specific ligand is one selected from the group consisting of anti- HER2/neu, folate, aptamer and TAT peptide.

[Claim 28]

<92> The method for cancer therapy according to claim 25, wherein the diameter of said silica core is between 50nm and 500nm.

[Claim 29]

<93> The method for cancer therapy according to claim 25, wherein the diameter of said gold outer shell is between 50nm and 500nm.

[Claim 30]

<94> The method for cancer therapy according to claim 25, wherein the diameter of said magnetic nanoparticle is between 2nm and 30nm.

[Claim 31]

<95> The method for cancer therapy according to claim 25, wherein the wavelength of said pulse is between 600nm and l,500nm.

[Claim 32]

<96> The method for cancer therapy according to claim 25, wherein the width of said pulse is between 1Ofs(femtosecond) and 200ps(picosecond).

[Claim 33]

<97> The method for cancer therapy according to claim 25, wherein the strength of said pulse is between 1 and 1,000 mW/cm² .

[Claim 34] <98> The method for cancer therapy according to claim 25, wherein the frequency of said pulse is between 0.1 and 10 kHz.