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6# J# 0 X# d# v 6# 6# 6# "Q "Q . 6# 6# 6# Q # # # # WW 6# 6# 6# 6# 6# 6# 6# 6# 6# | > : Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma
Monica Camerin,a Miguel Moreno,b Mara J. Marn,b Claire L. Schofield,b Isabelle Chambrier,b Michael J. Cook,b Olimpia Coppellotti,a Giulio Joria and David A. Russellb*
Dedicated to the memory of Giulio Jori; a great scientist, an excellent mentor and an even better friend.
a Department of Biology, University of Padova, 35131 Padova, Italy.
b School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, UK.
Email d.russell@uea.ac.uk
Abstract
Photodynamic therapy (PDT) is a treatment of cancer whereby tumours are destroyed by reactive oxygen species generated upon photoactivation of a photosensitizer drug. Hydrophobic photosensitizers are known to be ideal for PDT; however, their hydrophobicity necessitates that they are typically administered using emulsions. Here, a delivery vehicle for photodynamic therapy based on the co-self-assembly of both a Zn(II)-phthalocyanine derivative photosensitizer and a polyethylene glycol (PEG) derivative onto gold nanoparticles is reported. The PEG on the particle surface ensured that the conjugates were water soluble and enhanced their retention in the serum, improving the efficiency of PDT in vivo. The pharmacokinetic behaviour of the nanoparticle conjugates following intravenous injection into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma showed a significant increase of retention of the nanoparticles in the tumour. PDT tumour destruction was achieved 3 h following injection of the nanoparticle conjugates leading to a remarkable 40% of the treated mice showing no tumour regrowth and complete survival. These results highlight that dual functionalised nanoparticles exhibit significant potential in PDT of cancer especially for difficult to treat cancers such as amelanotic melanoma.
Introduction
Photodynamic therapy (PDT) is an innovative treatment for cancer that uses visible or near-infrared light to activate a photosensitizer drug ADDIN EN.CITE Dougherty199831603160316017Dougherty, Thomas J.Gomer, Charles J.Henderson, Barbara W.Jori, GiulioKessel, DavidKorbelik, MladenMoan, JohanPeng, QianPhotodynamic TherapyJournal of the National Cancer InstituteJournal of the National Cancer InstituteJ. Natl. Cancer Inst.889-90590121998June 17, 1998http://jnci.oxfordjournals.org/content/90/12/889.abstract10.1093/jnci/90.12.8891 to produce reactive oxygen species such as singlet oxygen, ADDIN EN.CITE Buchardt19767282728272826Buchardt, OlePhotochemistry of heterocyclic compoundsGeneral heterocyclic chemistry seriesviii, 622 p.Photochemistry.Heterocyclic compounds.1976New YorkWiley047111510X8008322 which destroy the cancerous tumour. ADDIN EN.CITE Weishaupt197672847284728417Weishaupt, Kenneth R.Gomer, Charles J.Dougherty, Thomas J.Identification of Singlet Oxygen as the Cytotoxic Agent in Photo-inactivation of a Murine TumorCancer ResearchCancer Research2326-2329367 Part 11976July 1, 1976http://cancerres.aacrjournals.org/content/36/7_Part_1/2326.abstract3 The ideal characteristics of a photosensitizer for PDT are: 1) must be isomerically pure; 2) should absorb light with high efficiency thus generating high quantum yields of singlet oxygen; and 3) should preferentially interact with the cancerous cells. ADDIN EN.CITE Jori199672787278727817Jori, GiulioTumour photosensitizers: approaches to enhance the selectivity and efficiency of photodynamic therapyJournal of Photochemistry and Photobiology B: BiologyJournal of Photochemistry and Photobiology B: BiologyJ. Photochem. Photobiol., B87-93362Tumour photosensitizersPhotofrin199611//1011-1344http://www.sciencedirect.com/science/article/pii/S1011134496073526http://dx.doi.org/10.1016/S1011-1344(96)07352-64 Numerous studies have highlighted that hydrophobic phthalocyanine photosensitizers are ideal for PDT ADDIN EN.CITE Josefsen201273977397739717Josefsen, Leanne B.Boyle, Ross W.Unique Diagnostic and Therapeutic Roles of Porphyrins and Phthalocyanines in Photodynamic Therapy, Imaging and TheranosticsTheranosticsTheranostics916-96629201210/04
05/09/received
08/10/acceptedSydneyIvyspring International Publisher1838-7640PMC3475217http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475217/10.7150/thno.4571PMC5 since they fulfil all three criteria: ADDIN EN.CITE Cook199574007400740017Cook, Michael J.Chambrier, IsabelleCracknell, Steven J.Mayes, Denise A.Russell, David A.OCTA-ALKYL ZINC PHTHALOCYANINES: POTENTIAL PHOTOSENSITIZERS FOR USE IN THE PHOTODYNAMIC THERAPY OF CANCERPhotochemistry and PhotobiologyPhotochemistry and Photobiology542-5456231995Blackwell Publishing Ltd1751-1097http://dx.doi.org/10.1111/j.1751-1097.1995.tb02381.x10.1111/j.1751-1097.1995.tb02381.x6 1) can be synthesised as single isomers; 2) have an intrinsic high extinction coefficient in the far-red region of the electromagnetic spectrum, which is ideal for tissue penetration; and 3) exhibit improved biodistribution within cancerous, rather than healthy, tissue. The drawback for such hydrophobic molecular photosensitizers is that they need to be dispersed within a delivery vehicle for in vivo therapy. Typical pharmaceutical delivery vehicles for hydrophobic molecules are emulsions such as Cremophor, although the direct introduction of an excessive concentration of the emulsion into the bloodstream can cause onset of an anaphylactic reaction. ADDIN EN.CITE Fabris200772867286728617Fabris, ClaraVicente, M. Graa H.Hao, ErhongFriso, ElisabettaBorsetto, LaraJori, GiulioMiotto, GiovanniColautti, PaoloMoro, DavideEsposito, JuanFerretti, AliceRossi, Carlo RiccardoNitti, DonatoSotti, GuidoSoncin, MarinaTumour-localizing and -photosensitising properties of meso-tetra(4-nido-carboranylphenyl)porphyrin (H2TCP)Journal of Photochemistry and Photobiology B: BiologyJournal of Photochemistry and Photobiology B: BiologyJ. Photochem. Photobiol., B131-1388923Photodynamic therapyBoron neutron capture therapyPorphyrinCarboraneMelanotic melanoma200712/14/1011-1344http://www.sciencedirect.com/science/article/pii/S1011134407001406http://dx.doi.org/10.1016/j.jphotobiol.2007.09.0127 Recently, the use of nanoparticle formulations to deliver the photosensitizer, either in combination with an emulsion or using water soluble nanoparticles, has become a common strategy in PDT. ADDIN EN.CITE Obaid20137382738273825Obaid, GirgisRussell, David A.Hamblin, Michael R.Huang, Ying-YingNanoparticles for Photodynamic Cancer TherapyHandbook of photomedicine367-3782013Boca Raton, FL.Taylor & Francis, CRC Press8 The transport of nanoparticles to tumour tissues is facilitated by the enhanced permeability and retention (EPR) effect, ADDIN EN.CITE Iyer200673857385738517Iyer, Arun K.Khaled, GreishFang, JunMaeda, HiroshiLaboratory of Microbiology and Oncology, Faculty of Pharmaceutical Sciences, Sojo University, Ikeda 862-0082, Japan.Exploiting the enhanced permeability and retention effect for tumor targetingDrug discovery todayDrug Discov TodayDrug discovery todayDrug Discov TodayDrug discovery todayDrug Discov Today812-8181117-18Drug Delivery Systems20062006/09//1359-644616935749http://europepmc.org/abstract/MED/16935749http://dx.doi.org/10.1016/j.drudis.2006.07.00510.1016/j.drudis.2006.07.005PubMedeng9 a phenomenon that is characteristic of solid tumours and does not occur in healthy tissue. To meet the demands of large amounts of nutrients and oxygen in tumour tissues, new blood vessels are rapidly formed that are leaky which induces the accumulation of blood plasma components, including macromolecules and nanoparticles, in the tumour. ADDIN EN.CITE Fang201172887288728817Fang, JunNakamura, HideakiMaeda, HiroshiThe EPR effect: Unique features of tumor blood vessels for drug delivery, factors involved, and limitations and augmentation of the effectAdvanced Drug Delivery ReviewsAdvanced Drug Delivery Reviews136-151633Drug targetingAngiogenesisSolid tumorsMacromolecular anticancer therapyNitroglycerinTumor vasculatureCancer chemotherapyAngiotensin II-induced hypertension20113/18/0169-409Xhttp://www.sciencedirect.com/science/article/pii/S0169409X10000906http://dx.doi.org/10.1016/j.addr.2010.04.00910 Thus, the EPR effect increases the passive accumulation of nanoparticles in the tumour and is currently used for tumour-targeting in the development of new anticancer drugs. ADDIN EN.CITE Chatterjee200811201120112017Chatterjee, Dev KumarFong, Li ShanZhang, YongNanoparticles in photodynamic therapy: An emerging paradigmAdvanced Drug Delivery ReviewsAdvanced Drug Delivery Reviews1627-163760152008Dec 140169-409XWOS:000261649800006<Go to ISI>://WOS:00026164980000610.1016/j.addr.2008.08.00311
While there have been numerous studies describing the use of nanoparticles for in vitro PDT, ADDIN EN.CITE Obaid20137382738273825Obaid, GirgisRussell, David A.Hamblin, Michael R.Huang, Ying-YingNanoparticles for Photodynamic Cancer TherapyHandbook of photomedicine367-3782013Boca Raton, FL.Taylor & Francis, CRC Press8 there are remarkably fewer studies detailing their in vivo PDT efficacy. ADDIN EN.CITE Voon201473327332733217Voon, Siew HuiKiew, Lik VoonLee, Hong BoonLim, Siang HuiNoordin, Mohamed IbrahimKamkaew, AnyaneeBurgess, KevinChung, Lip YongIn Vivo Studies of Nanostructure-Based Photosensitizers for Photodynamic Cancer TherapySmallSmall4993-50131024drug deliverynanostructuresin vivocancer therapyphotodynamic therapy20141613-6829http://dx.doi.org/10.1002/smll.20140141610.1002/smll.20140141612 Nanoparticles have been used, via intravenous injection or intratumour injection, for the treatment of various tumours and cell lines implanted in animal models including embryonic fibroblast, ADDIN EN.CITE Zhang200873927392739217Zhang, MinfangMurakami, TatsuyaAjima, KumikoTsuchida, KunihiroSandanayaka, Atula S. D.Ito, OsamuIijima, SumioYudasaka, MasakoFabrication of ZnPc/protein nanohorns for double photodynamic and hyperthermic cancer phototherapyProceedings of the National Academy of SciencesProceedings of the National Academy of Sciences14773-14778105392008September 30, 2008http://www.pnas.org/content/105/39/14773.abstract10.1073/pnas.080134910513 brain, ADDIN EN.CITE ADDIN EN.CITE.DATA 14, 15 head and neck, ADDIN EN.CITE ADDIN EN.CITE.DATA 16-18 melanoma, ADDIN EN.CITE Idris201225502550255017Idris, Niagara MuhammadGnanasammandhan, Muthu KumaraZhang, JingHo, Paul C.Mahendran, RathaZhang, YongIn vivo photodynamic therapy using upconversion nanoparticles as remote-controlled nanotransducersNat MedNat Med1580-158518102012Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.1078-895610.1038/nm.2933http://dx.doi.org/10.1038/nm.2933http://www.nature.com/nm/journal/v18/n10/abs/nm.2933.html#supplementary-information19 colon, ADDIN EN.CITE ADDIN EN.CITE.DATA 20-22 gastric, ADDIN EN.CITE ADDIN EN.CITE.DATA 23 liver, ADDIN EN.CITE Zhang201572957295729517Zhang, DaWu, MingZeng, YongyiWu, LingjieWang, QingtangHan, XiaoLiu, XiaolongLiu, JingfengChlorin e6 Conjugated Poly(dopamine) Nanospheres as PDT/PTT Dual-Modal Therapeutic Agents for Enhanced Cancer TherapyACS Applied Materials & InterfacesACS Applied Materials & Interfaces8176-818771520152015/04/22American Chemical Society1944-8244http://dx.doi.org/10.1021/acsami.5b0102710.1021/acsami.5b0102724 cervical, ADDIN EN.CITE Lv201572987298729817Lv, RuichanZhong, ChongnaLi, RuminYang, PiaopingHe, FeiGai, ShiliHou, ZhiyaoYang, GuixinLin, JunMultifunctional Anticancer Platform for Multimodal Imaging and Visible Light Driven Photodynamic/Photothermal TherapyChemistry of MaterialsChemistry of Materials1751-176327520152015/03/10American Chemical Society0897-4756http://dx.doi.org/10.1021/cm504566f10.1021/cm504566f25 and breast ADDIN EN.CITE ADDIN EN.CITE.DATA 26-28 cancer. The delivery of such nanosystems typically shows a suppression of the tumour growth when compared with tumours treated only with the photosensitizer drugs. In this field, we have investigated the efficiency, both in vitro and in vivo, of phthalocyanine functionalised gold nanoparticles for the treatment of cancer using PDT. ADDIN EN.CITE ADDIN EN.CITE.DATA 29-34 Our previous in vivo studies used a hydrophobic zinc phthalocyanine (C11Pc) derivative that was formulated as a nanoparticle construct (C11Pc-Np) using a phase transfer reagent. ADDIN EN.CITE Camerin201025672567256717Camerin, MonicaMagaraggia, MichelaSoncin, MarinaJori, GiulioMoreno, MiguelChambrier, IsabelleCook, Michael J.Russell, David A.The in vivo efficacy of phthalocyaninenanoparticle conjugates for the photodynamic therapy of amelanotic melanomaEuropean Journal of CancerEuropean Journal of Cancer1910-19184610NanoparticlesPhthalocyaninesSinglet oxygenPhotodynamic therapyPhotosensitisationMelanomaPharmacokinetics20100959-8049http://www.sciencedirect.com/science/article/pii/S0959804910001644http://dx.doi.org/10.1016/j.ejca.2010.02.03732 Since both were non-water soluble, the free C11Pc photosensitizer and the nanoparticle conjugate were injected into the animal model using a Cremophor emulsion. A direct comparison between the free C11Pc photosensitizer and the nanoparticle formulation showed that the half-life of the C11Pc in the serum was extended from 3.5 h to 6 h for the free photosensitizer and nanoparticle conjugate respectively. Additionally, it was also found that when the mice were treated with PDT 3 h after injection of the free or nanoparticle formulation of the C11Pc the mice remained tumour free for ca. 6 days. Subsequent tumour growth was shown to be appreciably faster for the mice that had received the free C11Pc photosensitizer treatment. For efficient PDT, delivery systems should be able to reduce the probability of opsonisation of nanoparticles in the bloodstream and the uptake by the reticuloendothelial system (RES). By functionalising the nanoparticles with a combination of polyethylene glycol (PEG) and photosensitizer drugs, the blood circulation time can be increased, the uptake by the RES can be reduced and consequently the accumulation of the nanoparticles in the tumours through the EPR effect can be achieved. ADDIN EN.CITE Chatterjee200811201120112017Chatterjee, Dev KumarFong, Li ShanZhang, YongNanoparticles in photodynamic therapy: An emerging paradigmAdvanced Drug Delivery ReviewsAdvanced Drug Delivery Reviews1627-163760152008Dec 140169-409XWOS:000261649800006<Go to ISI>://WOS:00026164980000610.1016/j.addr.2008.08.00311 Burda and co-workers reported the use of PEG functionalised gold nanoparticles carrying a non-covalently linked phthalocyanine for in vivo PDT of cancer. ADDIN EN.CITE ADDIN EN.CITE.DATA 35-38 Since the in vivo efficacy of nanoparticles for PDT increases with increased blood circulation time, it is clear that the development of delivery nanosystems with long circulation times in serum is appealing to further advance this therapy of cancer.
Here we present, for the first time, the synthesis and application of gold nanoparticles (Np) stabilised by the co-self-assembly of the hydrophobic zinc phthalocyanine (C11Pc) photosensitizer and a water soluble thiol-functionalised poly(ethylene glycol) (PEG) (C11Pc-Np-PEG, Fig. 1) for the in vivo delivery and PDT of amelanotic melanoma. We have chosen amelanotic melanoma since it represents 2-8% of malignant melanoma and remains a significant challenge to both diagnose and treat. ADDIN EN.CITE ADDIN EN.CITE.DATA 39, 40 Cutaneous melanoma are easily recognised due to the presence of characteristic pigmented areas within the tumour. However, amelanotic melanoma is a subtype of cutaneous melanoma with little or no pigmentation and therefore can be easily misdiagnosed as a benign lesion. Delays in diagnosis of amelanotic melanoma can result in patient mortality. ADDIN EN.CITE Thomas201473947394739417Thomas, N. E.Kricker, A.Waxweiler, W. T.et al.,Comparison of clinicopathologic features and survival of histopathologically amelanotic and pigmented melanomas: A population-based studyJAMA DermatologyJAMA Dermatology1306-13141501220142168-6068http://dx.doi.org/10.1001/jamadermatol.2014.134810.1001/jamadermatol.2014.134841 C11Pc and PEG were covalently attached to the gold surface via a gold-thiol bond to avoid the disassociation of the ligands from the nanoparticle surface following administration of the conjugates. The C11Pc-Np-PEG conjugates were injected into C57/BL6 mice bearing a subcutaneous transplanted B78H1 amelanotic melanoma. The pharmacokinetic investigations showed that the retention time of the conjugates in both the serum and in the tumour increased as compared with nanoparticles functionalised with C11Pc alone. The conjugates were eliminated via the bile-gut pathway without observable toxicity. Significantly, the irradiation of the tumours treated with the C11Pc-Np-PEG conjugates, 3 h after injection, resulted in the destruction of the tumour with 40% of the mice showing no tumour regrowth and complete survival.
Fig. 1. Schematic representation of the gold nanoparticle with the co-self-assembled C11Pc phthalocyanine derivative (blue ligand) and the PEG (red ligand) to form the water soluble C11Pc-Np-PEG conjugates.
Experimental section
Preparation and characterisation of the phthalocyanine PEG-nanoparticle conjugates (C11Pc-Np-PEG)
The photosensitizer (C11Pc) used in this study was obtained from 1,1,4,4,8,8,11,11,15,15,18,18-dodecakis(hexyl)-22,22-dimethyl-25,25-di(11,11-dithiaundecyl)diphthalocyaninato zinc as reported previously. ADDIN EN.CITE Chambrier199512612612617Chambrier,I.M.J.CookD.A.RussellSynthesis and Characterisation of Funtionalised Phthalocyanine Compounds for Fabrication of Self-Assembled MonolayersSynthesisSynthesis1283-1286101995Hone200273737317Hone, D. C.P. I. WalkerR. Evans-GowingS. FitzGeraldA. BeebyI. ChambrierM. J. CookD. A. RussellGeneration of Cytotoxic Singlet Oxygen via Phthalocyanine-Stabilized Gold Nanoparticles: A Potential Delivery Vehicle for Photodynamic TherapyLangmuirLangmuir2985-298718200233, 42 The phthalocyanine-polyethylene glycol (PEG) gold nano p a r t i c l e s ( C 1 1 P c - N p - P E G ) o f c a . 4 n m i n d i a m e t e r w e r e s y n t h e s i s e d a s f o l l o w s : t h e C 1 1 P c p h t h a l o c y a n i n e p r e c u r s o r ( 8 m g ) w a s d i s s o l v e d i n T H F ( 4 m L ) . P E G ( - t h i o - - c a r b o x y p o l y e t h y l e n e g l y c o l , 3 0 m g , I r i s B i o t e c h G m b H ; 3 2 7 4 D a ) i n T H F ( 8 m L ) w a s a d d e d , a n d the mixture was stirred vigorously for 5 min at room temperature. Gold (III) chloride trihydrate (4.8 mg in 4.8 ml of THF) was added to the solution with further stirring for 5 min. An aqueous solution of sodium borohydride (6 mg in 4.8 mL) was added drop-wise under permanent stirring. The solution was further stirred at room temperature overnight in the dark. The solvent was removed by rotary evaporation at 60 oC, and the particles were re-suspended in MES (2-(N-morpholino)ethanesulfonic acid) buffer, pH 5.5 with 0.05 % Tween 20. The particles were then centrifuged in polypropylene Eppendorf tubes (1 mL) at 14000 rpm for 30 min in an Allegra X-22R centrifuge. The supernatant containing the particles was removed from the pellet with a micropipette and then characterised using UV-Visible spectrophotometry and transmission electron microscopy.
Preparation of the PEGylated gold nanoparticle (Np-PEG) control particles
For control experiments, PEGylated gold nanoparticles (Np-PEG) were also prepared. PEG (30 mg) was dissolved in THF (12 mL), to which gold (III) chloride trihydrate (4.8 mg in 4.8 mL of THF) was added. The mixture was stirred vigorously for 5 min. Sodium borohydride (6 mg in 4.8 mL of H2O) was added, resulting in a dark brown solution which was stirred overnight. The particles were purified using the same methods as described above for the C11Pc-Np-PEG, resulting in a light brown solution of PEGylated gold nanoparticles.
Animals and tumours
Female C57/BL6 mice (18 20 g body weight) bearing a subcutaneously transplanted B78H1 amelanotic melanoma were used as the animal model for these investigations. The mice were obtained from Charles River (Como, Italy) and were kept in standard cages with free access to tap water and dietary food. The procedures adopted for animal treatment and tumour transplantation were approved by the University of Padovas ethical committee for the humane treatment of experimental animals. When the tumour diameter reached a value of 0.5 cm, the mice were injected into the caudal vein with 3.0 mol/Kg body weight of the C11Pc-Np-PEG conjugate. In agreement with the guidelines of the Italian ethical committee for humane treatment of experimental animals, the mice were sacrificed by euthanasia when the tumour volume reached 400 mm3, i.e. a size which could induce significant alterations of the animals metabolism or the occurrence of metastases.
Pharmacokinetic studies
Healthy and tumour-bearing mice were injected into the tail vein with 3.0 mol/Kg body weight of C11Pc-Np-PEG conjugates. At predetermined time intervals after injection, groups of three mice were sacrificed: blood samples were taken intracardiacally, centrifuged for 10 min at 3000 rpm and the sera thus collected were pooled and 50-fold diluted with THF. At the same time the tumour and selected normal tissues were rapidly excised, washed with physiological solution and a weighed amount of tissue (ca. 200 mg) was homogenised in 2% aqueous sodium dodecyl sulfate (SDS, 2 mL) using a Potter vessel. The homogenate was incubated for 1 h at room temperature under gentle magnetic stirring, then 0.25 mL of the suspension was diluted with THF (2.25 mL) and centrifuged at 3000 rpm for 10 min. Both the serum and the tissue extracts were assayed for the C11Pc content by reading the 640 nm-excited phthalocyanine fluorescence emission in the 660-850 nm spectral interval. The fluorescence intensity was converted into C11Pc concentration by interpolation with a calibration plot.
In a parallel set of studies, healthy mice injected with C11Pc-Np-PEG (3.0 mol/Kg body weight) were kept in metabolic cages and the urine and faeces samples were collected and analysed for the phthalocyanine content at 24 h intervals. A weighed amount of faeces (ca. 200 mg) was homogenised and incubated in 2% SDS, diluted into THF and analysed for the phthalocyanine content by fluorescence measurements as described for the tissues. The C11Pc content in the urine samples was analysed using a fluorimeter after direct dilution with THF.
Photodynamic therapy studies
Irradiation of the tumour-bearing mice was performed at 3 h, 24 h and 1 week after intravenous injection of the C11Pc-Np-PEG conjugate by using the 620-700 nm wavelength range isolated by optical filtering from the emission of a halogen lamp (Teclas, Lugano, Switzerland). The light source was operated at a fluence rate of 175 mW/cm2 for a total fluence of 157 J/cm2 (15 min irradiation). Further details of the irradiation procedure and the approach adopted to evaluate the effectiveness of the treatment have been described previously. ADDIN EN.CITE Camerin201025672567256717Camerin, MonicaMagaraggia, MichelaSoncin, MarinaJori, GiulioMoreno, MiguelChambrier, IsabelleCook, Michael J.Russell, David A.The in vivo efficacy of phthalocyaninenanoparticle conjugates for the photodynamic therapy of amelanotic melanomaEuropean Journal of CancerEuropean Journal of Cancer1910-19184610NanoparticlesPhthalocyaninesSinglet oxygenPhotodynamic therapyPhotosensitisationMelanomaPharmacokinetics20100959-8049http://www.sciencedirect.com/science/article/pii/S0959804910001644http://dx.doi.org/10.1016/j.ejca.2010.02.03732
Results and discussion
tic malignant melanoma is a subtype of
cutaneous melanoma with little or no pigment at
visual inspection.
1,2
A review of the literature indicates
that amelanotic melanomas (AM) represent 28% of all
malignant melanomas; the precise incidence is difficult
to calculate as the term amelanotic is often used to
indicate melanomas only partially devoid of pigment.
3
T r u l y A M a r e r a r e ; o f t e n s o m e p i g m e n t a t i o n i s p r e s e n t
a t t h e p e r i p h e r y o f t h e l e s i o n , a n d t h e a m e l a n -
o t i c D h y p o m e l a n o t i c m e l a n o m a ( A H M ) m i m i c s b e n i g n
a n d m a l i g n a n t v a r i a n t s o f b o t h m e l a n o c y t i c a n d
n o n m e l a n o c y t i c l e s i o n s .
2
A m e l a n o t i c m a l i g n a n t m e l a n o m a is a subtype of
cutaneous melanoma with little or no pigment at
visual inspection.
1,2
A review of the literature indicates
that amelanotic melanomas (AM) represent 28% of all
malignant melanomas; the precise incidence is difficult
to calculate as the term amelanotic is often used to
indicate melanomas only partially devoid of pigment.
3
T r u l y A M a r e r a r e ; o f t e n s o m e p i g m e n t a t i o n i s p r e s e n t
a t t h e p e r i p h e r y o f t h e l e s i o n , a n d t h e a m e l a n -
o t i c D h y p o m e l a n o t i c m e l a n o m a ( A H M ) m i m i c s b e n i g n
a n d m a l i g n a n t v a r i a n t s o f b o t h m e l a n o c y t i c a n d
n o n m e l a n o c y t i c l e s i o n s .
2
S y n t h e s i s a n d c h a r a c t e r i s a t i o n of C11Pc-Np-PEG conjugates
The photosensitizer unit (C11Pc) was obtained from the precursor molecule 1,1,4,4,8,8,11,11,15,15,18,18-dodecakis(hexyl)-22,22-dimethyl-25,25-di(11,11-dithiaundecyl)diphthalocyaninato zinc as reported previously. ADDIN EN.CITE Hone200273737317Hone, D. C.P. I. WalkerR. Evans-GowingS. FitzGeraldA. BeebyI. ChambrierM. J. CookD. A. RussellGeneration of Cytotoxic Singlet Oxygen via Phthalocyanine-Stabilized Gold Nanoparticles: A Potential Delivery Vehicle for Photodynamic TherapyLangmuirLangmuir2985-2987182002Chambrier199512612612617Chambrier,I.M.J.CookD.A.RussellSynthesis and Characterisation of Funtionalised Phthalocyanine Compounds for Fabrication of Self-Assembled MonolayersSynthesisSynthesis1283-1286101995