Transcript CANCER THERAPY Folate Receptor Endocytosis

NANOPARTICLES IN
TARGETED DRUG
DELIVERY FOR CANCER
THERAPY: Folate Receptor
Endocytosis
Madhu Smitha Harihara Iyer
BioE 494 – Atomic and Molecular Nanotechnology
4th December 2007
1
Cancer Cells
Lisa Brannon-Peppas and James O. Blanchette, “Nanoparticle and targeted systems for cancer therapy”, Advanced Drug Delivery Reviews
Volume.56, pp.1649– 1659 (2004)
2
A transmembrane
protein molecules
on the surface of
the cell that binds
to folate ligands
Ultimate goal - Selective destruction of cancer cells while sparing
normal tissues
Many human tumor cells, including ovarian, lung, breast,
endometrial, renal, and colon cancers. are known to overexpress
folate receptors
Folic acid binds to the folate receptors at the cell surface with very
high
affinitybyand
is internalized
by receptor-mediated endocytosis
A process
which
cells
Selective
can
internalizetargeting
molecules
by be achieved by folic acid conjugated
anticancer
the inwarddrugs
budding of
But
direct
conjugation
of folate to bioactive molecule can lead to loss
plasma
membrane
vesicles
ofcontaining
anti-tumor
activitywith
of the drug or alter the function of the conjugate
proteins
Hence
drug
carriers
receptor
sites
specificortodrug delivery systems are incorporated to
transport
anticancer
the molecules
beingdrugs to the tumoral sites by folic acid
conjugation
internalized.
Cancer Therapy
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[1] Moses O. Oyewumi, Robert A. Yokel, Michael Jay, Tricia Coakley, Russell J. Mumpe, “Comparison of cell uptake, biodistribution and tumor retention of folate-coated and
PEG-coated gadolinium nanoparticles in tumor-bearing mice”, Journal of controlled release, Vol.95, pp. 613-626 (2004)
[2] Antonio Quintana, Ewa Raczka, Lars Piehler, Inhan Lee, Andrzej Myc, Istvan Majoros, Anil K. Patri, Thommey Thomas, James Mule and James R. Baker, Jr., “Design and
Function of a Dendrimer-Based Therapeutic Nanodevice Targeted to Tumor Cells Through the Folate Receptor”, Pharmaceutical Research, Vol.19, Issue.9, pp.1310-1316 (2002)
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Receptor Mediated Endocytosis
4
http://srs.dl.ac.uk/VUV/home-page/hot-topics/endo.html
Drug Delivery Systems
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Drug remains concentrated in the carriers instead of
diffusing throughout the body.
Lower doses can be administered – fewer side effects
and lower cost of treatment
Conjugating targeting moieties to the carrier vehicles
increases the likelihood of the drug reaching the
tumoral site and minimizes uptake by non-target cells.
Slow release of the drug in the target site
The direct delivery and prolonged exposure increases
the effectiveness of the drug
http://www.inexpharm.com/Research/Inex_tcs.asp
Lisa Brannon-Peppas and James O. Blanchette, “Nanoparticle and targeted systems for cancer therapy”, Advanced Drug Delivery Reviews
Volume.56, pp.1649– 1659 (2004)
5
Nano Sized Drug Carriers
Carbon
Nanoparticles
Dendrimers
Gadolinium
Gold
Nanoparticles
Liposomes
Plant Virus
Shell CrossLinked
Nano Polymers
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Dendrimers
Nano-scale drug delivery molecules have several potential advantages like
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small size (<5.0 nm diameter) to escape the vasculature and target tumor cells
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molecule size below the threshold size for renal filtration to allow urinary excretion
which aids in avoiding retention in filter organs and metabolic clearance from the
liver.
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Large scale production as monodispersed populations
Generation 5 Polyamidoamine (PAMAM) dendrimers are stable, non-immunogenic, and
contain ample reactive sites (110 to 128 primary amines) on the surface for conjugation of
multiple chemical moieties like targeting ligands, radiopharmaceuticals, dyes and
contrast agents
The conformational structure of the generation 5 PAMAM, fluorescein, folic acid nanodevice
(G5-FITC-FA) was modeled using Molecular Dynamics simulations, in the hydrated
state to find modifications of the primary amine groups that would optimize targeting
1. Primary Amine – Local Branch Aggregation, internalization of FA, decreased receptor
interaction
2. 2,3-dihydroxypropyl – Surface overcrowding, partial internalization of FA, reduced access
to FA molecules
3. Carboxy - Local Branch Aggregation, internalization of FA, decreased receptor interaction
4. Acetamide - Extension of FA moiety on the surface suggesting potential receptor
interaction.
[1] Antonio Quintana, Ewa Raczka, Lars Piehler, Inhan Lee, Andrzej Myc, Istvan Majoros, Anil K. Patri, Thommey Thomas, James Mule and James R. Baker, Jr., “Design and
Function of a Dendrimer-Based Therapeutic Nanodevice Targeted to Tumor Cells Through the Folate Receptor”, Pharmaceutical Research, Vol.19, Issue.9, pp.1310-1316 (2002)
[2] Jolanta F. Kukowska-Latallo, Kimberly A. Candido, Zhengyi Cao, Shraddha S. Nigavekar, Istvan J. Majoros, Thommey P. Thomas, Lajos P. Balogh, Mohamed K.
Khan and James R. Baker, Jr., “Nanoparticle Targeting of Anticancer Drug Improves Therapeutic Response in Animal Model of Human Epithelial Cancer”, Cancer
Research, Vol.65, Issue.12, pp.5317-5324 (2005)
7
Carbon Nanotubes
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Single Walled Carbon Nanotubes (SWNTs) have a unique
property of absorbing light in the Near-Infra Red region (7001000 nm)
Selective
of SWNTs functionalized with folate
The processinternalization
for
moiety can employ this intrinsic property for destroying cancer
separation of
cells since biological tissues are transparent to light at NIR
mixtures by using
wavelength
centripetal force
The into
process
of disrupting
Anticancer drug transported
cancer
cells using SWNT can
biologic
material
by
use of rupture
be translocated to the cell nucleus by endosomal
triggered by NIR laser pulsesound wave energy
Also, excessive local heating of the SWNTs can destroy the
cancerous cells
Funtionalization of SWNT with folic acid is done using sonication
and centrifugation.
[1] Nadine Wong Shi Kam, Michael O’Connell, Jeffrey A. Wisdom, and Hongjie Dai,“Carbon nanotubes as multifunctional biological transporters and near-infrared agents for
selective cancer cell destruction”, Proceedings of the National Academy of Science, Vol.102, Issue.33, pp. 11600-11605 (2005)
8
Neutron capture therapy
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It is a potential cancer therapy which utilizes a stable nuclide
delivered to the tumor cells that can produce localized cytotoxic
radiations when irradiated by thermal or epithermal neutrons.
Gadolinium is a prospective NCT agent which can be effectively used
for treating cancer because of the Gd-neutron capture reaction
leading to emission of photons with tumor killing energy deposition at
longer ranges in tissues
It has large neutron capture cross sectional area which requires only
shorter neutron irradiation times
Additionally, Gd can also be used as contrast agent in magnetic
resonance imaging (MRI)
The engineering of the nanoparticles consisted of forming oil-in-water
microemulsions; Gadolinium Hexanedione incorporated to the matrix
while melting at 55°C; Followed by simple cooling the ternary system
of melted oil, surfactants and water to room temperature
[1] Moses O. Oyewumi, Russell J. Mumper, “Influence of formulation parameters on gadolinium entrapment and tumor cell uptake using folate-coated nanoparticles”,
International Journal of Pharmaceutics, Vol.251, Issue., pp.85-97 (2003)
[2] Moses O. Oyewumi, Robert A. Yokel, Michael Jay, Tricia Coakley, Russell J. Mumpe, “Comparison of cell uptake, biodistribution and tumor retention of folate-coated and
PEG-coated gadolinium nanoparticles in tumor-bearing mice”, Journal of controlled release, Vol.95, Issue., pp. 613-626 (2004)
9
Plant Virus – Nano Carriers
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Monodispersed nanosized protein cages were
prepared using the Hibiscus chlorotic ringspot
virus (HCRSV) to encapsulate doxorubicin, an
anticancer drug.
Folic acid was conjugated onto these
nanoparticles to impart cancer-targeting
capability.
The effective uptake of these nano delivery
systems and enhanced cytotoxicity of
doxorubicin int the ovarian cancer cells
TEM micrographs of (a) PC-DOX (b)fPC-DOX
and (c) Native HCRSV molecules after staining
with 1% Phosphotungstic acid. The sizes of
PC-DOX and fPC-DOX were comparable with
unmodified HCRSV
[1] Yupeng Ren, Sek Man Wong, and Lee-Yong Lim, “Folic Acid-Conjugated Protein Cages of a Plant Virus: A Novel Delivery Platform for Doxorubicin”,
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Bioconjugate Chemistry, Vol.18, Issue.3, pp. 836 – 843 (2007)
Shell Cross-Linked Carriers
• Unique amphiphilic core-shell
morphology
• Characterized by their
structural integrity and
functionality to attach receptor
specific ligands on its shell
surface
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[1] Dipanjan Pan, Jeffrey L. Turner and Karen L. Wooley, “Folic acid-conjugated nanostructured materials designed for cancer cell targeting” Chemical
Communications, Issue.19, pp.2400-2401 (2003)
Loaded Nano Drug Carrier
A, tumor-activated prodrug delivery and targeting. The anticancer agent is conjugated to a biocompatible
polymer via an ester bond. The linkage is hydrolyzed by cancer-specific enzymes or by high or low pH at
the tumor site, at which time, the nanoparticle releases the drug. B, self-assembled nanoparticles with
both diagnostic and therapeutic functions. These nanoparticles allow drug delivery as well as imaging of
tumor tissue
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[1] Rajni Sinha, Gloria J. Kim, Shuming Nie,and Dong M. Shin, “Nanotechnology in cancer therapeutics: bioconjugated nanoparticles for drug delivery”,
Molecular Cancer Theraphy, Vol.5, Issue.6, pp. 1909-1917 (2006)
Targetability and Survivability
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Unmodified Nanoparticles when injected into
the blood stream do not survive long in
circulation because of their nonspecific
recognition and removal by macrophages of
the reticuloendothelial system.
PEG coating is believed to prevent the
nonspecific adsorption of the nanoparticles
by the macrophages and removal from the
cell
Targetability of these nanoparticles to the
tumor site can be enhanced by attaching low
molecular weight folic acid as cell specific
ligands.
Occlusion of these FA ligands by large
molecules of PEG can be prevented by
attaching the ligands to the distal end of the
PEG chain
This way the ligands have high flexibility and
are free to extend away from the
nanoparticles surface to probe different
regions of a cell surface.
The Length and flexibility of the PEG
spacers also enable docking of the
nanoparticle on the cell surface by formation
of multiple tethers
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[1] Zhiping Zhang, Sie Huey Lee, Si-Shen Feng, “Folate-decorated poly(lactide-co-glycolide)-vitamin E TPGS nanoparticles for targeted drug delivery”, Biomaterials, Vol.28,
Issue. , pp.1889-1899 (2007)
Effect of PEG Spacer Length on Nanoparticle Internalization
• Spacers are the molecules interconnecting the ligands
and the nano-carrier.
• Liposomes containing fluorescent probe calcein, attached
to amino-PEG-SH spacers (250 Å), cysteine spacers (15
Å), lysine-SH spacers (22 Å) and no spacers were
introduced into KB cells and incubated for 4hrs at 37°C.
• The effective uptakes of liposomes per cell was
determined by fluorescent spectroscopy
• It can be seen that PEG conjugated liposomes were most
effectively internalized by the KB cells. T
• Higher length and flexibility of PEG spacer permits
formation of multiple tethers between a liposome and a
folate receptor cluster.
• The affinities of attachments were much greater than that
of the monovalent folates and hence better internalization
by the KB cells can be achieved.
Advantages of using folate mediated liposome over antibodies mediated
mechanism for targeted delivery of chemotherapeutic agents
• Folate is non allergenic while antibodies may elicit an immune response
• Folate mediates liposome endocytosis into non-lysosomal compartments whereas antibodies frequently
promote uptake into lysosomes
• Folate is compatible with PEG-derivatized lipids in contradistinction to antibody conjugated liposomes,
which lose their binding affinity upon incorporation of PEG lipids
• Folate ligand is inexpensive, stable during storage and in vivo circulation, intrinsically nontoxic to cells,
and easy to conjugate to the desired liposomes.
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[1] Robert J. Lee and Philip S.Low, “Delivery of Liposomes into Cultured KBCells via Folate Receptor-mediated Endocytosis”, The Journal of Biological Chemistry, Vol.269,
Issue.5, pp.3198-3204 (1994)
Zeta Potential
• Potential difference between the dispersion medium and the
stationary layer of fluid attached to the dispersed particle
• The value of zeta potential denotes the stability of the colloidal
dispersion
• Colloids with higher zeta potential are electrically stable as
compared to colloids with lower zeta potential which tend to
coagulate or flocculate
The increase in zeta potential for Poly(H2NPEGCAco-HDCA) at
acidic pH, as compared to Poly(hexadecyl cyanoacrylate) and
Poly(MePEGCA-co-HDCA) nanoparticles, signifies the
Electrokinetic
protonation of the amino group and their ready availability for
folic acidpotential
conjugationin a
Zeta Potential of Nanoparticles Measured
In acidic medium
Nanoparticle
Zeta Potential (mV)
PHDCA
−48.06 ± 0.20
MePEG2000CA-co-HDCA
−41.13 ± 0.50
H2NPEG3400CA-co-HDCA
−32.40 ± 2.10
colloidal system
Surface Plasmon Resonance Technology
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Facilitates real time analysis of molecular association
To study the interaction of folic acid-conjugated poly(H2NPEGCAco-HDCA) nanoparticles with the Folate Binding Protein (FBP)
Nonconjugated poly(H2NPEGCA-co-HDCA) nanoparticles were
used as control
FBP was immobilized on the sensor surface of a carboxylated,
activated, dextran-coated gold film
It was observed that the folate-conjugated nanoparticles have 10fold higher apparent affinity for the FBR than free folate and
displayed multivalent interaction with clusters of FBR.
[1] Barbara Stella, Silvia Arpicco, Maria T. Peracchia, Didier Desmaele, Johan Hoebeke, Michel Renoir, Jean D’Angelo, Luigi Cattel, and Patrick Couvreur, “Design of Folic AcidConjugated Nanoparticles for Drug Targeting”, Journal of Pharmaceutical Sciences, Vol.89, Issue.11, pp.1452-1464 (2000)
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Schematic representation of PEG conjugated Au Nanoparticles
introduced to FR+ and FR- cells
Evaluation of Cell Internalization of
Nanoparticles
TEM Micrographs of thin sections of cells that were incubated for
2 h with various AuNP constructs. Magnification of primary
images is 6000X
(A)
KB cells incubated with mPEG2000-T:AuNP. AuNP are found
adjacent to the cell plasma membrane (arrow)
(B)
KB cells incubated with F-PEG1500-T:AuNP. Region
corresponding to the higher magnification inset is denoted by the
arrow which shows significant uptake of nanoparticles throughout
the cytoplasm
(C)
KB cells incubated with F-PEG-T:AuNP in the presence of excess
folic acid
(D)
WI-38 cells incubated with F-PEG-T:AuNP.
[1] Vivechana Dixit, Jeroen Van den Bossche, Debra M. Sherman, David H. Thompson, and Ronald P. Andres, “Synthesis and Grafting of Thioctic Acid-PEG-Folate Conjugates
onto Au Nanoparticles for Selective Targeting of Folate Receptor-Positive Tumor Cells”, Journal of Biomedical Materials, Vol.17, Issue., pp. 603-609 (2006)
[2] Resham Bhattacharya, Chitta Ranjan Patra, Alexis Earl, Shanfeng Wang, Aaron Katarya, Lichun Lu, Jayachandran N. Kizhakkedathu, Michael J. Yaszemski, Philip R. Greipp,
Debabrata Mukhopadhyay, and Priyabrata Mukherjee, Attaching folic acid on gold nanoparticles using noncovalent interaction via different polyethylene glycol backbones and
targeting of cancer cells, Nanomedicine: Nanotechnology, Biology and Medicine, Vol.3, Issue., pp. 224-238 (2007)
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Confocal laser scanning
microscopy (CLSM)
C6 cancer cells were incubated
for 3 hrs at 37 °C with
(a) free DOX
(b) DOX formulated in the
nanoparticles of no TPGSFOL component in the blend
matrix
(c) DOX formulated in the 50%
TPGS-FOL nanoparticles
Confocal microscopic images
(light and fluroscent images) of
KB cells treated with acetamideG5-FITC-FA.
Figure A,B and C demonstrate
the binding and uptake of folic
acid dendrimer conjugates at
30min, 6hrs and 24hrs
respectively
Figure D corresponds to folic
acid nonconjugated acetamide
surfaced dendrimers
[1] Zhiping Zhang, Sie Huey Lee, Si-Shen Feng, “Folate-decorated poly(lactide-co-glycolide)-vitamin E TPGS nanoparticles for targeted drug delivery”, Biomaterials, Vol.28,
Issue. , pp.1889-1899 (2007)
[2] Antonio Quintana, Ewa Raczka, Lars Piehler, Inhan Lee, Andrzej Myc, Istvan Majoros, Anil K. Patri, Thommey Thomas, James Mule and James R. Baker, Jr., “Design and
Function of a Dendrimer-Based Therapeutic Nanodevice Targeted to Tumor Cells Through the Folate Receptor”, Pharmaceutical Research, Vol.19, Issue.9, pp.1310-1316 (2002)
17
Normal Cells
A549 Cells
HeLa Cells
Confocal images of Normal and HeLa
cells incubated in a solution PL-PEG-FA
conjugated SWNTs
• Normal Cells – without abundant folate
receprots, show little green fluorescence
inside the cells, confirming little uptake of
SWNTs
• HeLa Cells - Strong green fluorescence
inside cells confirms the SWNT uptake
with FA.
4T1 Cells
KB Cells
Cancer cell lines incubated with free Doxorubicin drug molecules, Doxorubicin loaded in Nanoparticles without FA,
and Doxorubicin loaded in FA conjugated Nanoparticles for 37 °C for 48 h
[1] Nadine Wong Shi Kam, Michael O’Connell, Jeffrey A. Wisdom, and Hongjie Dai,“Carbon nanotubes as multifunctional biological transporters and near-infrared agents for
selective cancer cell destruction”, Proceedings of the National Academy of Science, Vol.102, Issue.33, pp. 11600-11605 (2005)
18
References
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
Robert J. Lee and Philip S.Low, “Delivery of Liposomes into Cultured KBCells via Folate Receptor-mediated
Endocytosis”, The Journal of Biological Chemistry, Vol.269, Issue.5, pp.3198-3204 (1994)
Barbara Stella, Silvia Arpicco, Maria T. Peracchia, Didier Desmaele, Johan Hoebeke, Michel Renoir, Jean
D’Angelo, Luigi Cattel, and Patrick Couvreur, “Design of Folic Acid-Conjugated Nanoparticles for Drug
Targeting”, Journal of Pharmaceutical Sciences, Vol.89, Issue.11, pp.1452-1464 (2000)
Antonio Quintana, Ewa Raczka, Lars Piehler, Inhan Lee, Andrzej Myc, Istvan Majoros, Anil K. Patri, Thommey
Thomas, James Mule and James R. Baker, Jr., “Design and Function of a Dendrimer-Based Therapeutic
Nanodevice Targeted to Tumor Cells Through the Folate Receptor”, Pharmaceutical Research, Vol.19, Issue.9,
pp.1310-1316 (2002)
Dipanjan Pan, Jeffrey L. Turner and Karen L. Wooley, “Folic acid-conjugated nanostructured materials designed
for cancer cell targeting” Chemical Communications, Issue.19, pp.2400-2401 (2003)
Moses O. Oyewumi, Robert A. Yokel, Michael Jay, Tricia Coakley, Russell J. Mumpe, “Comparison of cell uptake,
biodistribution and tumor retention of folate-coated and PEG-coated gadolinium nanoparticles in tumor-bearing
mice”, Journal of controlled release, Vol.95, pp. 613-626 (2004)
Jolanta F. Kukowska-Latallo, Kimberly A. Candido, Zhengyi Cao, Shraddha S. Nigavekar, Istvan J. Majoros,
Thommey P. Thomas, Lajos P. Balogh, Mohamed K. Khan and James R. Baker, Jr., “Nanoparticle Targeting of
Anticancer Drug Improves Therapeutic Response in Animal Model of Human Epithelial Cancer”, Cancer
Research, Vol.65, Issue.12, pp.5317-5324 (2005)
Yupeng Ren, Sek Man Wong, and Lee-Yong Lim, “Folic Acid-Conjugated Protein Cages of a Plant Virus: A Novel
Delivery Platform for Doxorubicin”, Bioconjugate Chemistry, Vol.18, Issue.3, pp. 836 – 843 (2007)
Zhiping Zhang, Sie Huey Lee, Si-Shen Feng, “Folate-decorated poly(lactide-co-glycolide)-vitamin E TPGS
nanoparticles for targeted drug delivery”, Biomaterials, Vol.28, pp.1889-1899 (2007)
Susan Wang, Robert J. Lee, Greg Cauchon, David G. Gorenstein and Philips S. Low, “Delivery of antisense
oligodeoxyribonucleotides against the human epidermal growth factor receptor into cultured KB cells with
liposomes conjugated to folate via polyethylene glycol” Vol. 92, Issue.8, pp. 3318-3322 (1995)
Alberto Gabizon, Aviva T. Horowitz, Dorit Goren, Dinah Tzemach, Frederika Mandelbaum-Shavit, Masoud M.
Qazen, and Samuel Zalipsky, “Targeting Folate Receptor with Folate Linked to Extremities of Poly(ethylene
glycol)-Grafted Liposomes: In Vitro Studies”, Vol. 10, Issue.2, pp. 289-298 (1999)
Moses O. Oyewumi, Russell J. Mumper, “Influence of formulation parameters on gadolinium entrapment and
tumor cell uptake using folate-coated nanoparticles”, International Journal of Pharmaceutics, Vol.251, Issue.,
pp.85-97 (2003)
C. Vauthier, C. Dubernet, C. Chauvierre, I. Brigger, P. Couvreur, “Drug delivery to resistant tumors: the potential
of poly(alkyl cyanoacrylate) nanoparticles”, Journal of controlled release, Vol.93, Issue., pp.151-160 (2003)
19
References









Eun Kyoung Park, So Yeon Kim, Sang Bong Lee, Young Moo Lee, “Folate-conjugated methoxy poly(ethylene
glycol)/poly(ε-caprolactone) amphiphilic block copolymeric micelles for tumor-targeted drug delivery”, Journal of
Controlled Release,Vol. 109, Issue., pp. 158 - 168 (2005)
Sun Hwa Kim, Ji Hoon Jeong, Ki Woo Chun, and Tae Gwan Park, “Target-Specific Cellular Uptake of PLGA
Nanoparticles Coated with Poly(L-lysine)-Poly(ethylene glycol)-Folate Conjugate”, Langmuir, Vol.21, Issue.19, pp.
8852-8857 (2005)
Kumaresh S. Soppimath, Li-Hong Liu, Wei Yang Seow, Shao-Qiong Liu, Ross Powell, Peggy Chan, and Yi Yan Yang,
“Multifunctional Core/Shell Nanoparticles Self-Assembled from pH-Induced Thermosensitive Polymers for Targeted
Intracellular Anticancer Drug Delivery”, Advanced Functional Materials, Vol.17, Issue., pp. 355-362 (2007)
Resham Bhattacharya, Chitta Ranjan Patra, Alexis Earl, Shanfeng Wang, Aaron Katarya, Lichun Lu, Jayachandran N.
Kizhakkedathu, Michael J. Yaszemski, Philip R. Greipp, Debabrata Mukhopadhyay, and Priyabrata Mukherjee,
“Attaching folic acid on gold nanoparticles using noncovalent interaction via different polyethylene glycol
backbones and targeting of cancer cells”, Nanomedicine: Nanotechnology, Biology and Medicine, Vol.3, Issue., pp.
224-238 (2007)
Conroy Sun, Raymond Sze, Miqin Zhang, “Folic acid-PEG conjugated superparamagnetic nanoparticles for targeted
cellular uptake and detection by MRI”, Journal of Biomedical Materials, Vol. 78A, Issue., pp. 550-557 (2006)
Vivechana Dixit, Jeroen Van den Bossche, Debra M. Sherman, David H. Thompson, and Ronald P. Andres,
“Synthesis and Grafting of Thioctic Acid-PEG-Folate Conjugates onto Au Nanoparticles for Selective Targeting of
Folate Receptor-Positive Tumor Cells”, Journal of Biomedical Materials, Vol.17, Issue., pp. 603-609 (2006)
Rajni Sinha, Gloria J. Kim, Shuming Nie,and Dong M. Shin, “Nanotechnology in cancer therapeutics: bioconjugated
nanoparticles for drug delivery”, Molecular Cancer Theraphy, Vol.5, Issue.6, pp. 1909-1917 (2006)
Nadine Wong Shi Kam, Michael O’Connell, Jeffrey A. Wisdom, and Hongjie Dai, “Carbon nanotubes as
multifunctional biological transporters and near-infrared agents for selective cancer cell destruction”, Proceedings
of the National Academy of Science, Vol.102, Issue.33, pp. 11600-11605 (2005)
Lisa Brannon-Peppas and James O. Blanchette, “Nanoparticle and targeted systems for cancer therapy”, Advanced
Drug Delivery Reviews Volume.56, pp.1649– 1659 (2004)
20