Hybrid paclitaxel and gold nanorod-loaded human serum albumin nanoparticles for simultaneous chemotherapeutic and photothermal therapy on 4T1 breast cancer cells

The use of human serum albumin nanoparticles (HSAPs) as a drug carrier system for cancer treatment has proven successful through current marketable clinical formulations. Despite this success, there is a current lack of multifunctional HSAPs, which offer combinational therapies of more than one proven technique. Gold nanorods (AuNRs) have also shown medicinal promise due to their photothermal therapy capabilities. In this study, a desolvation and cross-linking approach was employed to successfully encapsulate gold nanorods into HSAPs simultaneously with the chemotherapeutic drug paclitaxel (PAC); forming PAC-AuNR-HSAPs with desirable overall particle sizes of 299 ± 6 nm. The loading efficiency of paclitaxel into PAC-AuNR-HSAPs reached up to 3 μg PAC/mg HSA. The PAC-AuNR-HSAPs experienced photothermal heating; with the bulk particle solution reaching up to 46 °C after 15 min of near-IR laser exposure. This heat increase marked the successful attainment of the temperature necessary to cause severe cellular hyperthermia and necrosis. The encasement strategy facilitated a colloidal hybrid treatment system capable of enhanced permeability and retention effects, photothermal ablation of cancer cells, and release of the active paclitaxel of up to 188 ng (from PAC-AuNR-HSAPs created with 30 mg HSA) in a single 15 min irradiation session. When treated with PAC-AuNR-HSAPs containing 20 μg PAC/mL particle solution, 4T1 mouse breast cancer cells experienced ∼82% cell death without irradiation and ∼94% cell death after just one irradiation session. The results for PAC-AuNR-HSAPs were better than that of free PAC, which only killed ∼77% of the cells without irradiation and ∼80% with irradiation. The hybrid particle system also lends itself to future customizable external functionalities via conjugated targeting ligands, such as antibodies. Internal entrapment of patient tailored medication combinations are also possible with this combination treatment platform, which may result in improved quality of life for those undergoing treatment.

Treatment of near-infrared photodynamic therapy using a liposomally formulated indocyanine green derivative for squamous cell carcinoma

Introduction

Photodynamic therapy (PDT) is a less invasive option for cancer treatment that has evolved through recent developments in nanotechnology. We have designed and synthesized a novel liposome system that includes an indocyanine green (ICG) derivative, ICG-C18, in its bilayer. In addition to its use as an optical imager to visualize blood, lymphatic, and bile flow, ICG has also been used as an optical sensitizer. In the present report, we evaluate the use of our novel liposome system, LP-ICG-C18, in PDT for squamous cell carcinoma in an autologous murine model.

Materials and Methods

An excitation pulse beam (300 μJ/pulse) of a single band (800 nm) was used for sensitization. The cytotoxicity of the photodynamic therapy was evaluated in terms of cellular morphology changes, methyl thiazolyl tetrazolium (MTT) assay results, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining. We tested the enhanced permeability and retention effect of LP-ICG-C18 in tumor-bearing C3H/He mice using a near-infrared fluorescence imaging system and fluorescence microscopy. We also examined the antitumor effect of PDT by measuring tumor volume in tumor-bearing mice.

Results

Cell death and apoptosis were only observed in the PDT group receiving LP-ICG-C18. LP-ICG-C18 itself had no cytotoxic activity and showed good biocompatibility. LP-ICG-C18 accumulated on the tumor 24 hours after injection and was retained for approximately 3 weeks. Tumor cell apoptosis following PDT with LP-ICG-C18 was also observed under optical microscopy, MTT assay, and TUNEL staining.

Conclusion

These findings suggest that LP-ICG-C18 may be an effective intervening material in PDT for malignant disease.

Analysis of the in vivo and in vitro effects of photodynamic therapy on breast cancer by using a sensitizer, sinoporphyrin sodium

Photodynamic therapy (PDT) is an emerging theranostic modality for various cancers and diseases. Photosensitizers are critical components for PDT. Sinoporphyrin sodium, referred to as DVDMS, is a newly identified photosensitizer that was isolated from Photofrin. Here, we evaluated the effects of DVDMS-mediated PDT (DVDMS-PDT) on tumor cell proliferation and metastasis in the highly metastatic 4T1 cell line and a mouse xenograft model. DVDMS-PDT elicited a potent phototoxic effect in vitro, which was abolished using the reactive oxygen species (ROS) scavenger N-acetylcysteine. In addition, DVDMS-PDT effectively inhibited the migration of 4T1 cells in scratch wound-healing and transwell assays. Using an in vivo mouse model, DVDMS-PDT greatly prolonged the survival time of tumor-bearing mice and inhibited tumor growth and lung metastasis, consistent with in vitro findings. PDT with DVDMS had a greater anti-tumor efficacy than clinically used Photofrin. Moreover, preliminary toxicological results indicate that DVDMS is relatively safe. These results suggest that DVDMS is a promising sensitizer that warrants further development for use in cancer treatment with PDT or other sensitizing agent-based therapies.

Breaking the depth dependency of phototherapy with Cerenkov radiation and low-radiance-responsive nanophotosensitizers

The combination of light and photosensitizers for phototherapeutic interventions, such as photodynamic therapy, has transformed medicine and biology. However, the shallow penetration of light into tissues and the reliance on tissue oxygenation to generate cytotoxic radicals have limited the method to superficial or endoscope-accessible lesions. Here we report a way to overcome these limitations by using Cerenkov radiation from radionuclides to activate an oxygen-independent nanophotosensitizer, titanium dioxide (TiO2). We show that the administration of transferrin-coated TiO2 nanoparticles and clinically used radionuclides in mice and colocalization in tumours results in either complete tumour remission or an increase in their median survival. Histological analysis of tumour sections showed the selective destruction of cancerous cells and high numbers of tumour-infiltrating lymphocytes, which suggests that both free radicals and the activation of the immune system mediated the destruction. Our results offer a way to harness low-radiance-sensitive nanophotosensitizers to achieve depth-independent Cerenkov-radiation-mediated therapy.

Combining magnetic hyperthermia and photodynamic therapy for tumor ablation with photoresponsive magnetic liposomes

The ongoing nanotech revolution has the potential to transform diagnostic and therapeutic methods. Stimuli-triggered nanotherapies based on remotely activated agents have become attractive alternatives to conventional chemotherapy. Herein, we designed an optimized smart nanoplatform based on dually loaded hybrid liposomes to achieve enhanced tumor therapy. The aqueous core was highly loaded with iron oxide nanoparticles, while the lipid bilayer was supplied with a photosensitizer payload. The double cargo translated into double functionality: generation of singlet oxygen under laser excitation and heat production under alternating magnetic field stimulation, coupling photodynamic therapy (PDT) to magnetic hyperthermia (MHT). These liposomes address both therapeutic agents within tumor cells, and the combined PDT/MHT therapy resulted in complete cancer cell death in vitro while total solid-tumor ablation was achieved in an in vivo rodent model.

UV-emitting upconversion-based TiO2 photosensitizing nanoplatform: near-infrared light mediated in vivo photodynamic therapy via mitochondria-involved apoptosis pathway

Photodynamic therapy (PDT) is a promising antitumor treatment that is based on the photosensitizers that inhibit cancer cells by yielding reactive oxygen species (ROS) after irradiation of light with specific wavelengths. As a potential photosensitizer, titanium dioxide (TiO2) exhibits minimal dark cytotoxicity and excellent ultraviolet (UV) light triggered cytotoxicity, but is challenged by the limited tissue penetration of UV light. Herein, a novel near-infrared (NIR) light activated photosensitizer for PDT based on TiO2-coated upconversion nanoparticle (UCNP) core/shell nanocomposites (UCNPs@TiO2 NCs) is designed. NaYF4:Yb(3+),Tm(3+)@NaGdF4:Yb(3+) core/shell UCNPs can efficiently convert NIR light to UV emission that matches well with the absorption of TiO2 shells. The UCNPs@TiO2 NCs endocytosed by cancer cells are able to generate intracellular ROS under NIR irradiation, decreasing the mitochondrial membrane potential to release cytochrome c into the cytosol and then activating caspase 3 to induce cancer cell apoptosis. NIR light triggered PDT of tumor-bearing mice with UCNPs@TiO2 as photosensitizers can suppress tumor growth efficiently due to the better tissue penetration than UV irradiation. On the basis of the evidence of in vitro and in vivo results, UCNPs@TiO2 NCs could serve as an effective photosensitizer for NIR light mediated PDT in antitumor therapy.

Trichophyton rubrum is inhibited by free and nanoparticle encapsulated curcumin by induction of nitrosative stress after photodynamic activation

Antimicrobial photodynamic inhibition (aPI) utilizes radical stress generated from the excitation of a photosensitizer (PS) with light to destroy pathogens. Its use against Trichophyton rubrum, a dermatophytic fungus with increasing incidence and resistance, has not been well characterized. Our aim was to evaluate the mechanism of action of aPI against T. rubrum using curcumin as the PS in both free and nanoparticle (curc-np) form. Nanocarriers stabilize curcumin and allow for enhanced solubility and PS delivery. Curcumin aPI, at optimal conditions of 10 μg/mL of PS with 10 J/cm² of blue light (417 ± 5 nm), completely inhibited fungal growth (p<0.0001) via induction of reactive oxygen (ROS) and nitrogen species (RNS), which was associated with fungal death by apoptosis. Interestingly, only scavengers of RNS impeded aPI efficacy, suggesting that curcumin acts potently via a nitrosative pathway. The curc-np induced greater NO^• expression and enhanced apoptosis of fungal cells, highlighting curc-np aPI as a potential treatment for T. rubrum skin infections.

Synthesis, optical properties and preliminary in vitro photodynamic effect of pyridyl and quinoxalyl substituted chlorins

A series of chlorophyll a-based chlorins conjugated with pyridyl or quinoxalyl group at different positions were synthesized, characterized and evaluated for their photodynamic effect in vitro. It was found that all the pyridyl and quinoxalyl chlorins showed promising photocytotoxicities but nontoxic without irradiation in HeLa cells, and the substituted types and positions had a significant influence on the photocytotoxicities of the chlorophyll a-based chlorins. All the chlorins with a pyridyl group at the C-D ring end exhibited relatively high photocytotoxicity as compared to those with 3(2)-pyridyl. Among them, compound 12 conjugated with a pyridyl group at its C12 position showed the best photodynamic effect in HeLa cells with an IC50 value of 0.033μM. These facts, associated with the relative high long wavelength absorptions of those chlorins may provide valuable ways to design and prepare promising photosensitizers for application in photodynamic therapy.

Multifunctional gold nanorods for selective plasmonic photothermal therapy in pancreatic cancer cells using ultra-short pulse near-infrared laser irradiation

Gold nanorods (AuNRs) have attracted considerable attention in plasmonic photothermal therapy for cancer treatment by exploiting their selective and localized heating effect due to their unique photophysical properties. Here we describe a strategy to design a novel multifunctional platform based on AuNRs to: (i) specifically target the adenocarcinoma MUC-1 marker through the use of the EPPT-1 peptide, (ii) enhance cellular uptake through a myristoylated polyarginine peptide (MPAP) and (iii) selectively induce cell death by ultra-short near infrared laser pulses. We used a biotin-avidin based approach to conjugate EPPT-1 and MPAP to AuNRs. Dual-peptide (EPPT-1+MPAP) labelled AuNRs showed a significantly higher uptake by pancreatic ductal adenocarcinoma cells when compared to their single peptide or avidin conjugated counterparts. In addition, we selectively induced cell death by ultra-short near infrared laser pulses in small target volumes (∼1 μm3), through the creation of plasmonic nanobubbles that lead to the destruction of a local cell environment. Our approach opens new avenues for conjugation of multiple ligands on AuNRs targeting cancer cells and tumors and it is relevant for plasmonic photothermal therapy.

Dendrimer-encapsulated naphthalocyanine as a single agent-based theranostic nanoplatform for near-infrared fluorescence imaging and combinatorial anticancer phototherapy

Multifunctional theranostic platforms capable of concurrent near-infrared (NIR) fluorescence imaging and phototherapies are strongly desired for cancer diagnosis and treatment. However, the integration of separate imaging and therapeutic components into nanocarriers results in complex theranostic systems with limited translational potential. A single agent-based theranostic nanoplatform, therefore, was developed for concurrent NIR fluorescence imaging and combinatorial phototherapy with dual photodynamic (PDT) and photothermal (PTT) therapeutic mechanisms. The transformation of a substituted silicon naphthalocyanine (SiNc) into a biocompatible nanoplatform (SiNc-NP) was achieved by SiNc encapsulation into the hydrophobic interior of a generation 5 polypropylenimine dendrimer following surface modification with polyethylene glycol. Encapsulation provides aqueous solubility to SiNc and preserves its NIR fluorescence, PDT and PTT properties. Moreover, an impressive photostability in the dendrimer-encapsulated SiNc has been detected. Under NIR irradiation (785 nm, 1.3 W cm(-2)), SiNc-NP manifested robust heat generation capability (ΔT = 40 °C) and efficiently produced reactive oxygen species essential for PTT and PDT, respectively, without releasing SiNc from the nanopaltform. By varying the laser power density from 0.3 W cm(-2) to 1.3 W cm(-2) the therapeutic mechanism of SiNc-NP could be switched from PDT to combinatorial PDT-PTT treatment. In vitro and in vivo studies confirmed that phototherapy mediated by SiNc can efficiently destroy chemotherapy resistant ovarian cancer cells. Remarkably, solid tumors treated with a single dose of SiNc-NP combined with NIR irradiation were completely eradicated without cancer recurrence. Finally, the efficiency of SiNc-NP as an NIR imaging agent was confirmed by recording the strong fluorescence signal in the tumor, which was not photobleached during the phototherapeutic procedure.

G-quadruplex DNA/protoporphyrin IX-based synergistic platform for targeted photodynamic cancer therapy

Photodynamic therapy (PDT) is an emerging technique to induce cancer cell death. However, the tumor specificity, cellular uptake and biodistribution of many photosensitizers urgently need to be improved. In this regard, we show here that the integrated nanoassemblies based on G-quadruplex DNAs (GQDs)/protoporphyrin IX (PPIX) can serve as a synergistic platform for targeted high-performance PDT. In the nanoassemblies, GQDs function as carriers of sensitiser PPIX and confers the system cancer cell targeting ability. After nucleolin-mediated efficient binding and cellular uptake of GQDs/PPIX assemblies, the strong red fluorescence of GQDs/PPIX complex provides a powerful tool for biological imaging. Moreover, the reactive oxygen species (ROS) generated by GQDs/PPIX under light illumination can effectively kill cancer cells. The present approach is simply composed by DNA and photosensitizers, thereby avoiding any complicated and time-consuming covalent modification or chemical labeling procedure.

Novel axially carborane-cage substituted silicon phthalocyanine photosensitizer; synthesis, characterization and photophysicochemical properties

The novel axially dicarborane substituted silicon (IV) (SiPc-DC) phthalocyanine was synthesized by treating silicon phthalocyanine dichloride SiPc(Cl)2 (SiPc) with o-Carborane monool. The compound was characterized by mass spectrometry, UV-Vis, FT-IR, (1)H and (11)B Nuclear Magnetic Resonance Spectroscopy (NMR). Spectral, photophysical (fluorescence quantum yield) and photochemical (singlet oxygen (ΦΔ) and photodegradation quantum yield (Φd)) properties of the complex were reported in different solutions (Dimethyl sulfoxide (DMSO), Dimethylformamide (DMF) and Toluene). The results of spectral measurements showed that both SiPc and carborane cage can have potential to be used as sensitizers in photodynamic therapy (PDT) and boron neutron capture therapy (BNCT) by their singlet oxygen efficiencies (ΦΔ=0.41, 0.39).

Plasmonic copper sulfide nanocrystals exhibiting near-infrared photothermal and photodynamic therapeutic effects

Recently, plasmonic copper sulfide (Cu2-xS) nanocrystals (NCs) have attracted much attention as materials for photothermal therapy (PTT). Previous reports have correlated photoinduced cell death to the photothermal heat mechanism of these NCs, and no evidence of their photodynamic properties has been reported yet. Herein we have prepared physiologically stable near-infrared (NIR) plasmonic copper sulfide NCs and analyzed their photothermal and photodynamic properties, including therapeutic potential in cultured melanoma cells and a murine melanoma model. Interestingly, we observe that, besides a high PTT efficacy, these copper sulfide NCs additionally possess intrinsic NIR induced photodynamic activity, whereupon they generate high levels of reactive oxygen species. Furthermore, in vitro and in vivo acute toxic responses of copper sulfide NCs were also elicited. This study highlights a mechanism of NIR light induced cancer therapy, which could pave the way toward more effective nanotherapeutics.

Resolving the Benzophenone DNA-Photosensitization Mechanism at QM/MM Level

Benzophenone, the parent of the diarylketone family, is a versatile compound commonly used as a UV blocker. It may also trigger triplet-based DNA photosensitization. Therefore, benzophenone is involved in DNA photodamage induction. In the absence of experimentally resolved structure, the mechanism of DNA damage production remains elusive. Employing a hybrid quantum mechanics/molecular mechanics approach, here we address the spin transfer mechanism between this drug and proximal thymine, that is, the DNA nucleobase most prone to suffer triplet damages.

Optical and photoacoustic dual-modality imaging guided synergistic photodynamic/photothermal therapies

Phototherapies such as photodynamic therapy (PDT) and photothermal therapy (PTT), due to their specific spatiotemporal selectivity and minimal invasiveness, have been widely investigated as alternative treatments of malignant diseases. Graphene and its derivatives not only have been used as carriers to deliver photosensitizers for PDT, but also as photothermal conversion agents (PTCAs) for PTT. Herein, we strategically designed and produced a novel photo-theranostic platform based on sinoporphyrin sodium (DVDMS) photosensitizer-loaded PEGylated graphene oxide (GO-PEG-DVDMS) for enhanced fluorescence/photoacoustic (PA) dual-modal imaging and combined PDT and PTT. The GO-PEG carrier drastically improves the fluorescence of loaded DVDMS via intramolecular charge transfer. Concurrently, DVDMS significantly enhances the near-infrared (NIR) absorption of GO for improved PA imaging and PTT. The cancer theranostic capability of the as-prepared GO-PEG-DVDMS was carefully investigated both in vitro and in vivo. This novel theranostics is well suited for fluorescence/PA dual-modal imaging and synergistic PDT/PTT.

Generation-dependent templated self-assembly of biohybrid protein nanoparticles around photosensitizer dendrimers

In this article, we show the great potential of dendrimers for driving the self-assembly of biohybrid protein nanoparticles. Dendrimers are periodically branched macromolecules with a perfectly defined and monodisperse structure. Moreover, they allow the possibility to incorporate functional units at predetermined sites, either at their core, branches, or surface. On these bases, we have designed and synthesized negatively charged phthalocyanine (Pc) dendrimers that behave as photosensitizers for the activation of molecular oxygen into singlet oxygen, one of the main reactive species in photodynamic therapy (PDT). The number of surface negative charges depends on dendrimer generation, whereas Pc aggregation can be tuned through the appropriate choice of the Pc metal center and its availability for axial substitution. Remarkably, both parameters determine the outcome and efficiency of the templated self-assembly process by which a virus protein forms 18 nm virus-like particles around these dendritic chromophores. Protein-dendrimer biohybrid nanoparticles of potential interest for therapeutic delivery purposes are obtained in this way. Biohybrid assemblies of this kind will have a central role in future nanomedical and nanotechnology applications.

Photochemical approaches to vision restoration

Photoswitches are traditional pharmacologic agonists, antagonists, or channel blockers that are covalently modified with an azobenzene derivative. Azobenzene undergoes wavelength-dependent isomerization between cis and trans conformation. For some photoswitches, only one of these configurations is biologically active, resulting in light-dependent activation or inhibition of function. Photoswitches that feature a quaternary ammonium coupled to the azobenzene moiety cause light-dependent neuronal depolarization due to blockage of voltage-gated potassium channels. Two photoswitch strategies have been pursued. In the one-component strategy, the photoswitch is applied to native receptors; in the two-component strategy, the photoswitch is combined with virally-mediated expression of a genetically modified receptor, to which the photoswitch may covalently bind. The former approach is simpler but the latter allows precise anatomic targeting of photoswitch activity. Acrylamide-azobenzene-quaternary ammonium (AAQ) is the prototypical first-generation one-component photoswitch. When applied to retinas with outer retinal degeneration, ganglion cell firing occurs in response to blue light, and is abrogated by green light. In vivo, AAQ restored pupillary light responses and behavioral light responses in blind animals. DENAQ is a prototypical second generation one-component photoswitch. It features spontaneous thermal relaxation so cell firing ceases in dark, and features a red-shifted activation spectrum. Interestingly, DENAQ only photoswitches in retinas with outer retinal degeneration. MAG is a photoswitched glutamate analog which covalently binds to a modified ionotropic glutamate receptor, LiGluR. When applied together, MAG and LiGluR also rescue physiologic and behavioral light responses in blind mice. Together, photoswitch compounds offer a potentially useful approach to restoration of vision in outer retinal degeneration.

Transferrin receptor-targeted theranostic gold nanoparticles for photosensitizer delivery in brain tumors

Therapeutic drug delivery across the blood-brain barrier (BBB) is not only inefficient, but also nonspecific to brain stroma. These are major limitations in the effective treatment of brain cancer. Transferrin peptide (Tfpep) targeted gold nanoparticles (Tfpep-Au NPs) loaded with the photodynamic pro-drug, Pc 4, have been designed and compared with untargeted Au NPs for delivery of the photosensitizer to brain cancer cell lines. In vitro studies of human glioma cancer lines (LN229 and U87) overexpressing the transferrin receptor (TfR) show a significant increase in cellular uptake for targeted conjugates as compared to untargeted particles. Pc 4 delivered from Tfpep-Au NPs clusters within vesicles after targeting with the Tfpep. Pc 4 continues to accumulate over a 4 hour period. Our work suggests that TfR-targeted Au NPs may have important therapeutic implications for delivering brain tumor therapies and/or providing a platform for noninvasive imaging.

Plasmon-enhanced photoelectrochemical water splitting using au nanoparticles decorated on hematite nanoflake arrays

Hematite nanoflake arrays were decorated with Au nanoparticles through a simple solution chemistry approach. We show that the photoactivity of Au-decorated Fe2 O3 electrodes for photoelectrochemical water oxidation can be effectively enhanced in the UV/Visible region compared with the bare Fe2 O3 . Au-nanoparticle-decorated Fe2 O3 nanoflake electrodes exhibit a significant cathodic shift of the onset potential up to 0.6 V [vs. reversible hydrogen electrode (RHE)], and a two times increase in the water oxidation photocurrent is achieved at 1.23 VRHE . A maximum photocurrent of 2.0 mA cm(-2) at 1.6 VRHE is obtained in 1 M KOH under AM 1.5 (100 mW cm(-2) ) conditions. The enhancement in photocurrent can be attributed to the Au nanoparticles acting as plasmonic photosensitizers that increase the optical absorption.

Photocatalytic carbon dioxide reduction with rhodium-based catalysts in solution and heterogenized within metal-organic frameworks

The first photosensitization of a rhodium-based catalytic system for CO2 reduction is reported, with formate as the sole carbon-containing product. Formate has wide industrial applications and is seen as valuable within fuel cell technologies as well as an interesting H2 -storage compound. Heterogenization of molecular rhodium catalysts is accomplished via the synthesis, post-synthetic linker exchange, and characterization of a new metal-organic framework (MOF) Cp*Rh@UiO-67. While the catalytic activities of the homogeneous and heterogeneous systems are found to be comparable, the MOF-based system is more stable and selective. Furthermore it can be recycled without loss of activity. For formate production, an optimal catalyst loading of ∼10 % molar Rh incorporation is determined. Increased incorporation of rhodium catalyst favors thermal decomposition of formate into H2 . There is no precedent for a MOF catalyzing the latter reaction so far.

Self-assembled core-shell nanoparticles for combined chemotherapy and photodynamic therapy of resistant head and neck cancers

Combination therapy enhances anticancer efficacy of both drugs via synergistic effects. We report here nanoscale coordination polymer (NCP)-based core-shell nanoparticles carrying high payloads of cisplatin and the photosensitizer pyrolipid, NCP@pyrolipid, for combined chemotherapy and photodynamic therapy (PDT). NCP@pyrolipid releases cisplatin and pyrolipid in a triggered manner to synergistically induce cancer cell apoptosis and necrosis. In vivo pharmacokinetic and biodistribution studies in mice show prolonged blood circulation times, low uptake in normal organs, and high tumor accumulation of cisplatin and pyrolipid. Compared to monotherapy, NCP@pyrolipid shows superior potency and efficacy in tumor regression (83% reduction in tumor volume) at low drug doses in the cisplatin-resistant human head and neck cancer SQ20B xenograft murine model. We elucidated the in vitro/vivo fate of the lipid layer and its implications on the mechanisms of actions. This study suggests multifunctional NCP core-shell nanoparticles as a versatile and effective drug delivery system for potential translation to the clinic.

Titania coated upconversion nanoparticles for near-infrared light triggered photodynamic therapy

Because of the limited penetration depth of visible light that generally excites most of the available photosensitizers (PSs), conventional photodynamic therapy (PDT) is limited to the treatment of superficial and flat lesions. Recently, the application of deep penetrating near-infrared (NIR) light excitable upconversion nanoparticles (UCNs) in conjunction with PDT has shown to have clear potential in the treatment of solid tumors due to its ability to penetrate thick tissue. However, various constructs developed so far have certain limitations such as poor or unstable PS loading, reducing their therapeutic efficacy and limiting their application to solution or cell-based studies. In this work, we present a method to fabricate uniform core-shell structured nanoconstruct with a thin layer of photocatalyst or PS-titanium dioxide (TiO2) stably coated on individual UCN core. Our design allows controllable and highly reproducible PS loading, preventing any leakage of PS compared to previously developed nanoconstructs, thus ensuring repeatable PDT results. Further surface modification of the developed nanoconstructs with polyethylene glycol (PEG) rendered them biocompatible, demonstrating good therapeutic efficacy both in vitro and in vivo.

Spectroscopic and structural insights on molecular assembly consisting high potential zinc phthalocyanine photosensitizer attached to PyC60 through non-covalent interaction

Efforts to improve the ease of self-assembly formation through non-covalent interaction has led to the development of zinc phthalocyanine (zinc-2,9,16,23-tetra-tert-butyl phthalocyanine, i.e., ZnPc) as a high potential photosensitizer molecule towards C60 pyrrolidine tris-acid ethyl ester (PyC60) in toluene and 1,2-dichlorobenzene (DCB). Steady state fluorescence experiment elicits efficient quenching of the fluorescence intensity of both H2- and ZnPc in presence of PyC60. The average value of binding constant for PyC60/H2-Pc and PyC60/ZnPc systems in toluene (DCB) are determined to be 9910 (13,460) and 12,710 (24,060) dm(3) mol(-1), respectively. Lifetime experiment yields ∼3 times larger magnitude of charge separated rate constant for the PyC60/ZnPc system compared to PyC60/H2-Pc in toluene. Photoinduced energy transfer between PyC60 and H2- (/ZnPc) has been evidenced with nanosecond laser photolysis method; transient absorption studies establish that energy transfer from (T)PyC60(∗) to H2- and ZnPc occurs predominantly, as confirmed by the consecutive appearance of the triplet states of PyC60.

Development of therapeutic Au-methylene blue nanoparticles for targeted photodynamic therapy of cervical cancer cells

Photodynamic therapy (PDT) involves the cellular uptake of a photosensitizer (PS) combined with oxygen molecules and light at a specific wavelength to be able to trigger cancer cell death via the apoptosis pathway, which is less harmful and has less inflammatory side effect than necrosis. However, the traditional PDT treatment has two main deficiencies: the dark toxicity of the PS and the poor selectivity of the cellular uptake of PS between the target cells and normal tissues. In this work, methylene blue (MB), a known effective PS, combined with Au nanoparticles (NPs) was prepared using an intermolecular interaction between a polystyrene-alt-maleic acid (PSMA) layer on the Au NPs and MB. The Au@polymer/MB NPs produced a high quantum yield of singlet oxygen molecules, over 50% as much as that of free MB, when they were excited by a dark red light source at 660 nm, but without significant dark toxicity. Furthermore, transferrin (Tf) was conjugated on the Au@polymer/MB NPs via an EDC/NHS reaction to enhance the selectivity to HeLa cells compared to 3T3 fibroblasts. With a hand-held single laser treatment (32 mW/cm) for 4 min, the new Au@polymer/MB-Tf NPs showed a 2-fold enhancement of PDT efficiency toward HeLa cells over the use of free MB at 4 times dosage. Cellular staining examinations showed that the HeLa cells reacted with Au@polymer/MB-Tf NPs and the 660 nm light excitation triggered PDT, which caused the cells to undergo apoptosis ("programmed" cell death). We propose that applying this therapeutic Au@polymer/MB-Tf nanoagent is facile and safe for delivery and cancer cell targeting to simultaneously minimize side effects and accomplish a significant enhancement in photodynamic therapeutic efficiency toward next-generation nanomedicine development.

Multi-channel LED light source for fluorescent agent aided minimally invasive surgery

Cancer is one of the most common and deadly diseases around the world. Amongst all the different treatments of cancer such as surgery, chemotherapy and radiation therapy, surgical resection is the most effective. Successful surgeries greatly rely on the detection of the accurate tumor size and location, which can be enhanced by contrast agents. Commercial endoscope light sources, however, offer only white light illumination. In this paper, we present the development of a LED endoscope light source that provides 2 light channels plus white light to help surgeons to detect a clear tumor margin during minimally invasive surgeries. By exciting indocyanine green (ICG) and 5-Aminolaevulinic acid (ALA)-induced protoporphyrin IX (PPIX), the light source is intended to give the user a visible image of the tumor margin. This light source is also portable, easy to use and costs less than $300 to build.