American Society for Photobiology

ASP Conference 2016: 21-26 May 2016
Tampa Marriott Waterside Hotel & Marina

Single Session

[Schedule Grid]

P1 - Poster Session I

Florida 6   18:00 - 20:00

P1-2   Photocaged Carbohydrates As Versatile Tools For Synthetic Bio(techno)logy And Single Cell Applications D Binder*, University Dusseldorf, FZ Juelich ; C Bier, University Dusseldorf, FZ Juelich; F Hilgers, University Dusseldorf, FZ Juelich; A Graberger, IBG-1, FZ Juelich; A Loeschcke, University Dusseldorf, FZ Juelich; D Kohlheyer, IBG-1, FZ Juelich; J Pietruszka, University Dusseldorf, FZ Juelich; KE Jaeger, University Dusseldorf, FZ Juelich; T Drepper, University Dusseldorf, FZ Juelich

Abstract: Optogenetic tools are light-responsive components that allow for a simple triggering of cellular functions with unprecedented spatiotemporal resolution and in a non-invasive fashion. In particular, light-regulated gene expression exhibits an enormous potential for various biotechnological and synthetic biology applications. Here, we report on the development and evaluation of light-responsive microbial expression systems based on caged compounds such as photocaged IPTG or arabinose. These photocaged carbohydrates are highly feasible to accurately control target gene expression in different biotechnologically relevant production hosts in a rapid and gradual fashion. Microfluidic single cell analysis further revealed that native expression heterogeneity, observed for conventional inducer molecules, can be abrogated by using photocaged carbohydrates as inducers. Apparently, their increased membrane-permeability superseded specific inducer uptake systems. Finally, the biotechnological applicability of light-responsive inducers was demonstrated by distinct improvements of production yields for terpenoids and antibiotics produced in different industrially relevant Gram-positive and Gram-negative expression hosts. In vivo expression analyses revealed that photocaged carbohydrates together with their corresponding transcriptional regulator/promoter system can be employed as optogenetic plug-and-play modules for synthetic biology approaches. These expression modules can be applied in novel photomicrobioreactors and single cell cultivation platforms to precisely control expression of target genes and thereby fully automatize the optimization of microbial production processes. Especially for closed (e.g. anaerobic) systems and increasing numbers of parallelized expression cultures, non-invasive and spatiotemporal light induction will provide a higher-order control.

P1-4   Major inter-individual variation in the UVB induced increase and maximal level of 25-hydroxy vitamin D P Datta, Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark ; PA Philipsen*, Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark; P Olsen, Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark; B Petersen, Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark; P Johansen, Department of Forensic Medicine,University of Copenhagen, Copenhagen, Denmark; N Morling, Department of Forensic Medicine,University of Copenhagen, Copenhagen, Denmark; HC Wulf, Department of Dermatology, Bispebjerg Hospital, Copenhagen, Denmark

Abstract: Vitamin D influences skeletal health as well as other aspects of human health. Even when the most obvious sources of variation such as solar UVB exposure, latitude, season, clothing habits, skin pigmentation and ethnicity are selected for, variation in the serum 25-hydroxy vitamin D (25(OH)D) response to UVB remains extensive and unexplained. Our study assessed the inter-individual variation in 25(OH)D response to UVR and the maximal obtainable 25(OH)D level in 22 healthy participants (220 samples) with similar skin pigmentation during autumn/winter from October through December with negligible ambient UVB. During nine weeks the participants received identical UVB doses on identical body areas until a maximal level of 25(OH)D was reached. To examine if the maximal 25(OH)D level had been reached the participants were subsequently sent on a one-week sun holiday in Hurghada, Egypt. Major inter-personal variation in both the maximal obtainable UVB-induced 25(OH)D level (range 85-216 nmol/l, mean 134 nmol/l) and the total increase in 25(OH)D (range 3-139 nmol/l, mean 48 nmol/l) was found. Linear modelling including measured 25(OH)D baselines as personal intercepts explained 54.9% of the variation. By further including individual personal slopes in the model, as much as 90.8% of the observed variation could be explained. The explained variation constituted by personal differences in slopes thus represented 35.9%. Age, vitamin D receptor gene polymorphisms, height and constitutive skin pigmentation (a skin area not exposed to UVB) explained 15.1% of this variation. In total this linear model explained 70% of the observed variation. Despite elimination of most known external sources of variation, our study demonstrated inter-individual variation corresponding to an observed maximal difference of 136 nmol/l in the total increase of 25(OH)D and 131 nmol/l in the maximal level of 25(OH)D.

P1-5   A Non-Invasive Modality for In Vivo Detection of Neutrophil Influx in Preclinical Models of Mesothelioma RW Davis*, University of Pennsylvania ; J Miller, University of Pennsylvania; M Yuan, University of Pennsylvania; TM Busch, University of Pennsylvania

Abstract: Photodynamic therapy (PDT) frequently leads to a rapid influx of innate immune cells, most especially neutrophils, into the site of treatment. Signals released by these neutrophils help to steer the adaptive immune response, and it is therefore no surprise that their depletion is associated with poorer outcomes in preclinical studies of tumor models. Conversely, treatment resistance can develop due to instigation of survival factors that include vascular endothelial growth factor (VEGF) and endothelial growth factor receptor (EGFR), or if the adaptive immune response is driven toward a more regulatory subset. These relationships are further complicated when PDT is performed in the context another inflammation-inducing treatment, such as surgery. In order to better understand the spatial and temporal aspects of neutrophil influx during and after intraoperative PDT, we have used a non-invasive, chemiluminescent modality for the in vivo detection of neutrophils in pre-clinical models of mesothelioma. Mice bearing AB12 (murine mesothelioma) tumors were injected intraperitoneally with luminol, which releases light in the presence of peroxide radicals produced by the neutrophil enzyme myeloperoxidase. Studies were performed to longitudinally evaluate the effects of surgery, followed by PDT, in contrast to PDT as an individual entity. Using this technique, neutrophil influx was readily detected after even minor injury. Moreover, this modality was able to differentially distinguish the spatial localization of neutrophils to the incision and PDT-treated sites. Ongoing studies will seek to correlate this influx with the expression of resistance factors and tumor response in mesothelioma models, towards the goal of understanding the induction of innate immunity in combinations of PDT with surgery.

P1-6   What is Photobiology? An Introduction for High School Students. FP Gasparro*, Hamden Hall Country Day School

Abstract: This year a group of very talented Tampa area high school students will be attending our meeting for a day. They will be the Tampa Area Science Fair Finalists and they will be setting up their posters for our expert scientists to view. In addition, they have been invited to attend a special symposium in which several ASP members will be asked to present their work at a high school level. In this introductory talk, I will give an overview of the basics of photochemistry and photobiology so that the students will be familiar with some of the terminology and elementary principles. The primary purpose of this symposium is to introduce these talented students to the idea of conducting phootbiology research and thus to consider choosing photobiology as a field of study and career

P1-7   Combination of verteporfin-PDT and PI3K pathway inhibitor BEZ235 synergistically enhances endothelial cell growth inhibition and apoptosis DE Kraus*, University of the Sciences ; B Chen, University of the Sciences

Abstract: Photodynamic therapy (PDT) induces cell injury and death through generation of reactive oxygen species (ROS) after light activation. Verteporfin is a photosensitizer that has been approved for the treatment of age-related macular degeneration and is under investigation for vascular-targeted cancer therapy. Verteporfin-mediated PDT induces rapid apoptotic cell death in SVEC mouse endothelial cells by activating mitochondria-initiated cell death pathways. However, we found that PDT activated pro-survival phosphatidylinositol 3-kinase (PI3K) signaling pathway, which was associated with cell regrowth after treatment. Thus, the goal of this study is to test the hypothesis that the therapeutic outcome of verteporfin-PDT can be enhanced by targeting PDT-induced pro-survival PI3K/mTORC signaling pathway. In this study, we combined verteporfin-PDT and dual PI3K/mTORC pathway inhibitor, BEZ235 to enhance treatment response in SVEC cells. We found that compensatory upregulation of PI3K/mTORC signaling post PDT was significantly inhibited by BEZ235 as indicated by a dramatic reduction in the phosphorylation of AKT and s6 protein. Our results demonstrate that combining PDT with BEZ235 not only induced more cell apoptosis but also resulted in more durable inhibition in cell proliferation. Enhanced treatment outcome of this combination therapy was shown by both short-term cell proliferation and long-term clonogenic assay. These results provide the basis that targeting pro-survival PI3K signaling pathway is an effective approach for enhancing therapeutic response to verteporfin-PDT.

P1-8   Therapeutic Enhancement of Aminolevulinic Acid-based Tumor Imaging and Therapy P Palasuberniam*, University of the Sciences in Philadelphia ; B Chen, University of the Sciences in Philadelphia

Abstract: Photodynamic therapy (PDT) involves the combination of a photosensitizer and light of a specific wavelength. Upon light activation in the presence of oxygen, photosensitizer molecules generate reactive oxygen species that cause cytotoxicity by inducing oxidative stress. Aminolevulinic acid (ALA) is a pro-drug used for the diagnosis and PDT treatment of various solid tumors based on endogenous production of heme precursor protoporphyrin IX (PpIX). Although nearly all types of human cells express heme biosynthesis enzymes and produce PpIX, tumor cells are found to have more PpIX production and accumulation than normal cells, allowing for the detection and treatment of solid tumors. The objective of my research is to explore therapeutic approaches to enhance ALA-based tumor detection and therapy. We have found that high ABCG2 transporter activity in triple negative breast cancer cells (TNBC) contributed to reduced PpIX levels in cells, causing them to be more resistant towards ALA-PDT. The administration of an ABCG2 inhibitor, Ko143, was able to reverse cell resistance to ALA-PDT by enhancing PpIX mitochondrial accumulation and sensitizing cancer cells to ALA-PDT. Ko143 treatment had little effect on PpIX production and ALA-PDT in normal and ER- or HER2-positive cells. Furthermore, since some tyrosine kinase inhibitors (TKI) are known to block ABCG2 transporter activity, we screened a panel of tyrosine kinase inhibitors to examine its effect on enhancing PpIX fluorescence and ALA-PDT efficacy. Several TKIs including lapatinib and gefitinib showed effectiveness in increasing ALA-PpIX fluorescence in TNBC leading to increased cell death after PDT administration. These results indicate that inhibiting ABCG2 transporter using TKIs is a promising approach for targeting TNBC with ALA-based modality.

P1-9   Plasmonic Nanocomposites for Rapid Tissue Sealing and Repair K Rege*, Arizona State University (ASU) ; RR Urie, ASU; TJ Flake, ASU; M Mushaben, Montana State University (MSU); JJ Heys, MSU; M Jaffe, Midwestern University

Abstract: Laser tissue welding is a potential alternative to sutures or staples that are conventionally used for tissue approximation in soft tissue surgeries. Laser tissue welding is a technique where a chromophore absorbs photons and converts them into heat to seal apposed tissue edges. Significant barriers to laser tissue welding including insufficient closure strength and extensive thermal damage have hindered the clinical application of this technique. In this work, we overcome these barriers in ex vivo tissue welding and spatiotemporal modeling. In this presentation we discuss results of ex vivo laser tissue welding using gold nanorod-elastin-like polypeptide crosslinked matrices, gold nanorod-collagen hydrogels, and gold nanorod-silk thin films. These plasmonic biopolymer nanocomposites were shown to return up to 68% of native tissue tensile strength and 54% of native tissue bursting point pressure. Additionally, we discuss the predictions of a spatiotemporal model developed to optimize the parameter space in laser tissue welding.

P1-10   Guidelines for Defining Type I and II Photosensitized Oxidation MS Baptista, Institute of Chemistry, University of Sao Paulo ; J Cadet, University de Sherbrooke; P Di Mascio, Institute of Chemistry, University of Sao Paulo; AA Ghogare*, Brooklyn College and Graduate Center of the City University of New York; A Greer, Brooklyn College and Graduate Center of the City University of New York; MR Hamblin, Massachusetts General Hospital and Harvard Medical School; C Lorente, INIFTA, Universidad Nacional de La Plata (UNLP) and CONICET; MS Ribeiro, Institute of Energy and Nuclear Research; A Thomas, INIFTA, Universidad Nacional de La Plata (UNLP) and CONICET; M Vignoni, INIFTA, Universidad Nacional de La Plata (UNLP) and CONICET

Abstract: Here, ten tips are presented for a standardized definition of type I and II photosensitized oxidation reactions. Because of varied notions of photosensitized oxidation reactions, a checklist of recommendations is provided for their definitions. Type I and type II reactions are oxygen-dependent and involve unstable species such as peroxyl radical and singlet oxygen. This exercise was an outgrowth of a mini-symposium on singlet oxygen chemistry in Cambury, Brazil in 2014.


Abstract: Dermatological impact of pollution is not yet fully characterized, however skin is probably exposed to very low concentrations of pollutants. In fact, literature suggests that Polycyclic Aromatic Hydrocarbons (PAH) could be provided either by topical penetration of ultrafine particles or by systemic distribution from lungs through blood circulation. Phototoxic impacts of particulate matter PM, PM extract and various PAH on normal human keratinocytes exposed to daily UV (d-UV from 300-400 nm) or to UVA1 (340-400 nm) were compared. Surprisingly, UVA1 was often as potent as d-UV (and sometimes more) in impairing cell survival. Moreover, benzo[a]pyrene (BaP) and indeno[1,2,3-cd]pyrene (IcdP) were phototoxic at very low concentrations (few nanomoles per litre), consistent with concentrations reported in blood of smokers or people exposed to strong pollution. Reactive oxygen species were generated within cells by co-exposure to BaP or IcdP and UVA1, suggesting that photo-oxidative stress contributed to cell death. Finally, comparison of the photoprotection provided to keratinocytes by two formulations differing in their UVA absorption ability confirmed the impact of wavelengths longer than 340 nm in such a "photo-polluting" stress. Our results emphasized the need of an appropriate daily photoprotection for people living in polluted area.

P1-12   Investigating the Chemical Composition of Human Retinal Lipofuscin in Association with Age Related Macular Degeneration (AMD) K Denius*, NIU ; JC Tournear, NIU; ER Gaillard, NIU

Abstract: Age related macular degeneration (AMD) is a common retinal disorder that affects the elderly and is the leading cause of blindness in the Western world. The excess buildup of lipofuscin in the retinal pigment epithelium (RPE) is considered to be a major risk factor for AMD. RPE lipofuscin, thought to be derived from the ingestion of photoreceptor cells' outer segments, has the capability of causing photooxidative damage from excessive visible light exposure. A2E is a commonly studied fluorophore known to be a component of RPE lipofuscin. This study aims to look at the photoreactivity of A2E and its possible reactions with amino acids under blue light exposure. Human retinal lipofuscin is isolated from human donor eyes diagnosed with AMD according to the method previously described by Feeney-Burns. The organic soluble fraction of lipofuscin is collected, dried, and reconstituted using methanol for use in high performance liquid chromatography tandem mass spectrometry (LC/MS) coupled with a photo diode array and fluorescence detectors. Separately, A2E is synthesized and reacted with various amino acids under blue light conditions. The products are then analyzed using the same methods as RPE lipofuscin and results are compared to that found in the human donor tissue. Results show possible reactions with particular amino acids and A2E, particularly that of lysine. Post-translational modifications of lysine have commonly been associated with inflammation and disease. These data suggests the vulnerability of amino acids and protein in vivo to photooxidative damage elicited by A2E. Further analysis can assist in determining the pathogenesis of AMD and the role A2E plays in disease progression.

P1-13   Impact of human skin dermis on the repair efficiency of UV-induced DNA damage in the epidermis MM Dorr*, Université Laval and Centre Hospitalier Universitaire de Québec Research Center ; PJ Rochette, Université Laval and Centre Hospitalier Universitaire de Québec Research Center

Abstract: Skin, constituted of the epidermis and the dermis, is exposed to solar ultraviolet radiations (UVR). Exposure to UVR leads to the generation of cyclobutane pyrimidine dimers (CPD), a highly mutagenic DNA damage responsible for skin cancer driver mutations. An efficient CPD repair is important to avoid mutation induction and skin cancer. A previous study brought evidence that the interactions between dermal fibroblasts and epidermal keratinocytes play a role in promoting epidermal CPD repair after UVB irradiation. However, very little is known about the mechanisms involved and the factors responsible for this dermal-epidermal crosstalk modulating UV-induced damage repair in keratinocytes. We used a tissue-engineered skin model to investigate the impact of dermis and its components on epidermal CPD repair. This skin model is produced exclusively from human fibroblasts and keratinocytes. Fibroblasts were cultured for 35 days in the presence of ascorbic acid to have them secrete and assemble their own extracellular matrix and thus form a thick fibrous dermal sheet, on top of which keratinocytes were seeded and grew during 10 days. We compared CPD repair, after 400 J/m^2 UVB, in keratinocytes seeded either on dermal sheet or on culture dish plastic. We observe a faster repair of epidermal CPD in the presence of a dermal sheet. We are now investigating which element of the dermis is influencing CPD repair efficiency in epidermal cells, i.e. extracellular matrix components and/or fibroblasts secreted factors. This project aim to shed light on the influence of dermal components on epidermal CPD repair efficiency and will help to determine the nature of these constituents. Understanding how the fibroblast"keratinocyte crosstalk influences response to UVB-induced genotoxicity represents an important step toward skin cancer prevention.

P1-15   Mitochondrial Reactive Oxygen Species Accelerated Cellular Uptake of 5-Aminolevulinic Acid in Gastric Cancer Cells H Ito*, University of Tsukuba ; M Tamura, University of Tsukuba; H Matsui, University of Tsukuba; HP Indo, Kagoshima University; MJ Majima, Kagoshima University

Abstract: 5-aminolevulinic acid (ALA), which is a precursor of heme, has been clinically used for photodynamic therapy (PDT) and photodynamic diagnosis (PDD). Cancer cell specific porphyrin accumulation used to be involved by ALA treatment, whereas a mechanism had not been elucidated. There could be following three mechanisms for porphyrin accumulation in cancer: â‘ Inhibition of ALA metabolism, â‘¡Promotion of ALA uptake, and â‘¢Inhibition of porphyrins We recently reported that over-generation of endogenous nitric oxide (NO) by gene transfection of inducible NO synthase (iNOS) inactivated ferrochelatase, which is an enzyme to chelate iron into porphyrin structure, to enhance porphyrin accumulation .Thus, this mechanism is likely to contribute cancer specific porphyrin accumulation. However, the uptake level and the pathway of ALA were not unclear. It is known that a membrane transporter, PEPT1 is a major transporter of ALA and is expressed in gastric cancer. We have been confirmed that a gastric cancer cell line over-generate reactive oxygen species from mitochondria (mitROS). We hypothesized that mitROS affected upregulation of PEPT1 and accelerated cellular uptake of ALA. In this study, we clarified about â‘¡ that mitROS induced PEPT1 expression and cancer cell specific uptake of ALA using following cell lines: rat gastric mucosal cells RGM1, its cancer-like mutated cells RGK1, and manganese superoxide dismutase (MnSOD) overexpressed RGK cells RGK-MnSOD. Since MnSOD is expressed in mitochondria, mitROS can be specifically scavenged. We demonstrated cancer specific upregulation of PEPT1 and observed downregulation in RGK-MnSOD cells. Additionally, radio-labelled ALA was incorporated in RGK1 rather than RGK-MnSOD. In conclusion, cancer cellular mitROS induced PEPT1 upregulation and acceleration of ALA uptake. In addition, we are now investigating about porphyrin excretion from cells, â‘¢.

P1-16   B6-Vitamers are Endogenous Photosensitizers of Photo-oxidative and Genotoxic Stress in Cultured Human Keratinocytes and Reconstructed Epidermis R Justiniano*, UA Cancer Center and College of Pharmacy, University of Arizona ; SL Park, UA Cancer Center and College of Pharmacy, University of Arizona; JD Williams, UA Cancer Center and College of Pharmacy, University of Arizona; J Perer, UA Cancer Center and College of Pharmacy, University of Arizona; JL Lesson, UA Cancer Center and College of Pharmacy, University of Arizona; GT Wondrak, UA Cancer Center and College of Pharmacy, University of Arizona

Abstract: UVA-driven cutaneous photo-oxidative stress may originate from specific endogenous chromophores acting as photosensitizers. Recently, we have documented the photosensitization of cultured human skin keratinocytes and fibroblasts exposed to micromolar concentrations of B6-vitamers (pyridoxine/pyridoxamine/pyridoxal) causing UVA-driven inhibition of proliferation, cell cycle arrest, and apoptosis. Here, we demonstrate that B6-vitamers are micromolar sensitizers of photo-oxidative and genotoxic stress in cultured human keratinocytes and reconstructed epidermis. First, induction of apoptosis was substantiated by flow cytometric analysis of annexinV-FITC/PI-stained primary keratinocytes exposed to the combined action of UVA (6.6 J/cm2) and B6-vitamer (order of potency: pyridoxal > pyridoxine = pyridoxamine). Flow cytometric assessment of DCF fluorescence and chemiluminescent detection of glutathione depletion confirmed the occurrence of photo-oxidative stress elicited by combined exposure to UVA and B6-vitamers. Comparative gene expression array analysis revealed that combined exposure to pyridoxal and UVA induced pronounced ER (DDIT3, HSPA6) and redox (EGR1, GSTM3, SOD1) stress responses in primary keratinocytes. Comet analysis indicated the introduction of Fpg-sensitive oxidative DNA base lesions observable only in response to combined B6/UVA exposure. In human reconstructed epidermis (EpidermTM; MatTek), pyridoxal pre-incubation followed by UVA exposure caused genomic 8-oxo-dG and TUNEL positivity, substantiating the occurrence of UVA-driven photodynamic effects that may be relevant to human skin exposed to high concentrations of B6-vitamers.

P1-17   Sustained Release Liposomal Drug Delivery for Treating Ocular Angiogenesis DK Karumanchi*, Northern Illinois University ; YV Pantoja, Northern Illinois University; AM Street, Northern Illinois University; DA Freeman, Northern Illinois University; FA Roth, Northern Illinois University; ER Gaillard, Northern Illinois University

Abstract: Diabetic Retinopathy (DR) and Age Related Macular Degeneration (AMD) are the most common ocular diseases and a leading cause of blindness in American adults. Angiogenesis observed in these two diseases is characterized by the growth of new blood vessels into the retina damaging its surface in the process. The new blood vessels are fragile, "leaky" and pool blood into the retinal space, further damaging the retina. Laser treatments and drugs like Lucentis and Avastin are available for controlling the diseases. These drugs are anti-VEGF antibodies that inhibit the growth of new blood vessels. The intravitreal injections, administered every month are inconvenient, painful as well as very expensive. Our interest in this research project is to encapsulate the protein drug in nanostructures, prolong the time of drug release into the eye, thereby, decreasing the frequency as well as the cost factor for these treatments. Liposomes are artificial vesicles composed of phospholipids and cholesterol which form lipid bilayers and a hollow hydrophilic core where the drugs can be encapsulated. Abrishami et al have been able to obtain a sustained release of the anti-VEGF drugs up to a period of 42 days. We have been successful in encapsulating a model protein into our stable liposomal formulations and attain a controlled release over a period of 6 months in vitro. Currently, we are studying the in vivo drug release kinetics and distribution using Dutch belted rabbits as animal models to test the efficacy of the nanocarrier. With this study, our efforts would be to decrease the frequency of intravitreal injections from 12 to 2 per year, thereby effectively making the treatment more economically feasible.

P1-18   Biological Effects of Heat Generated by Infrared Exposure on Human Skin in vivo MA Kim*, Amorepacific R&D Center ; YC Jung, Amorepacific R&D Center; EJ Kim, Amorepacific R&D Center; HK Lee, Amorepacific R&D Center

Abstract: Human skin is constantly exposed to sunlight, which comprises 6.8% of ultraviolet (290-400nm), 38.9% of visible light (400-760nm), and 54.3% of infrared radiation (760nm-1mm). Recently, not only the ultraviolet (UV) responses, but the effect of infrared (IR) radiation on human skin has been studied. IR spectral region has been known to cause premature skin aging, and the heat generated by IR might be involved in the skin aging as well. Since the heat is known to regulate the expression of MMP-1, MMP-3, MMP-12 and tropoelastin, fibrillin-1. To prevent this premature aging, the effective IR or heat blockers are being developed widely. However, the appropriate clinical evaluation method for this efficacy has not been studied heretofore. In this study, we investigated the biological impact of heat generated by IR on human skin in vivo, in order to set up the evaluation method. Thirteen healthy subjects participated in a study of IR radiation. Subjects exposed their back side, which is the region between scapula line and waist, to the IR emitter. Measurements were conducted on baseline, and after IR irradiance of 0.24W/cm^2 in a room with controlled temperature and relative humidity (24±2ºC and 40±2%). Skin surface temperature, erythema, and blood flow of IR exposed region were measured. As a result, the skin surface temperature and the erythema significantly increased after IR exposure, compared to the baseline. Skin blood flow also significantly increased as well. The molecular vibrations and rotations might lead to the increase of skin surface temperature, and the temporarily appeared erythema is thought to be affected by increased blood flow and vasodilation. From the results, biophysical properties of skin surface temperature, erythema, and blood flow could be evaluating indices for the heat protection efficacy measurement. Further studies regarding materials which are effective for the heat protection and the standardized evaluating method should be investigated.

P1-19   "˜All-in-One' Photodynamic Device and its Performance for In-vivo Sensitizer Release AG Ghogare*, Brooklyn College and The Graduate Center of the City University of New York ; JM Miller, University of Pennsylvania; B Mondal, College of Staten Island and The Graduate Center of the City University of New York; AM Lyons, College of Staten Island and The Graduate Center of the City University of New York; KA Cengel, University of Pennsylvania; TM Busch, University of Pennsylvania; A Greer, Brooklyn College and The Graduate Center of the City University of New York

Abstract: This poster describes progress in the development of an all-in-one PDT device for local delivery of sensitizer, oxygen and illumination. Questions we sought to address included: Does the silica device tip biofoul? Do cells adhere to the tip and impede sensitizer photorelease? Does fluorination of the tip increase biofouling resistance in the pointsource PDT technique? In this regard, we have used biomaterial (e.g., proteins, cells, etc.) from SQ20B head and neck tumors and whole blood for an assessment of fouling of the silica tips by adsorption. It was shown that by exchanging the native silica tip for a fluorinated tip, a better non-stick property led to an increased sensitizer output by ~10%. The fluorinated tip gave a sigmoidal photorelease where singlet oxygen is stabilized to physical quenching, whereas the native silica tip with unprotected SiO"H groups gave a slower (pseudolinear) photorelease. A further benefit from fluorinated silica is that 15% less biomaterial adheres to its surface compared to native silica based on a bicinchoninic acid assay (BCA) and X-ray photoelectron spectroscopy (XPS) measurements. We discuss how the fluorination of the device tip increases biofouling resistance and can contribute to a new pointsource PDT tool.

P1-20   Phase Separation of Reactive Oxygen Species: Singlet Oxygen Chemistry at Interfaces AA Ghogare*, Brooklyn College and Graduate Center of the City University of New York ; B Malek, Brooklyn College; W Fang, Brooklyn College; N Walalawela, Brooklyn College and Graduate Center of the City University of New York; R Choudhury, Brooklyn College; Y Liu, College of Staten Island and Graduate Center of the City University of New York; Y Zhao, College of Staten Island and Graduate Center of the City University of New York; Q Xu, College of Staten Island and Graduate Center of the City University of New York; AM Lyons, College of Staten Island and Graduate Center of the City University of New York; A Greer, Brooklyn College and Graduate Center of the City University of New York

Abstract: Highlights are described from our studies of interfacial singlet oxygen. The talk will provide examples of surfactant traps for airborne singlet oxygen at the air-water interface (with the sensitizer "in absentia"), and the regioselective formation and characterization of surfactant hydroperoxides. The preparation of a 3-D printed superhydrophobic surface and first example of a triphasic photosensitizer with regions that are controllably dry, partly wetted, and/or fully wetted will also be discussed. Singlet oxygen was directly detected by its NIR luminescence at 1270 nm at or above the air-liquid surface, in the plastron of the superhydrophobic surface and within water. Singlet oxygen is fascinating, not in a singular way, but from the multiplicity of reactions it undergoes. The above reactions are of utility in synthesis or are biologically relevant models of singlet oxygen at membrane or marine aerosol surfaces.

P1-21   Oral Vitamin D3 As A Neoadjuvant For Combination Photodynamic Therapy (cPDT): Preclinical Studies In A Murine Model To Predict The Therapeutic Response In Vitamin D3 Deficient Human Populations S Anand*, Cleveland Clinic ; E Thomas, Cleveland Clinic; T Hasan, Harvard Medical School; EV Maytin, Cleveland Clinic

Abstract: Combination PDT (cPDT), in which the tumor is preconditioned with a differentiation-promoting agent prior to ALA-PDT, is a promising and evolving approach for the treatment of non-melanoma skin cancers. We have shown that a cPDT approach using the active hormonal form of vitamin D3 (calcitriol) given systemically prior to PDT, resulted in elevated protoporphyrin (PpIX) levels and subsequent PDT-induced cell death in A431 SCC tumors. However, since calcitriol may pose a risk for hypercalcemia in humans, we replaced calcitriol with natural dietary vitamin D3 (D3; 10-fold) fed over a 10-day period. In this study, we asked whether vitamin D3 deficiency might alter the PpIX-elevating response. Nude mice were fed with a D3 deficient diet for 4, while control mice were fed the normal diet. Human A431 SCC cells were implanted subcutaneously, and the mice were then either switched to a 10K diet or given a HED of 50,000 IU D3 by oral gavage. Tumors and tissues including skin and serum (to measure vitamin D3 levels) were collected for analyses. Following D3 supplementation, a tumor-selective increase in the levels of PpIX and in expression of markers of differentiation (E-Cadherin) was observed in both the D3-deficient and the normal control mice. As compared to other methods of VD delivery, a pretreatment regimen involving 10 days of a 10K diet, the response was similar in VD-deficient and normal mice with respect to the PpIX levels in the tumors, whereas 3 days of a 10K diet was insufficient to bring PpIX levels to the same level as in normal mice. Serum levels of D3 and its metabolic intermediates, and expression levels of heme- and vitamin D3-metabolic enzymes in tumors, skin, and other tissues were analyzed and were supportive of the PpIX induction results. These data suggest that a clinical study using oral vitamin D3 as a neoadjuvant is a new promising approach that could be effective for the treatment of human skin cancer in both normal and VD-deficient populations.

P1-22   Zinc Phthalocyanine functionalised gold nanoparticles for photodynamic cancer therapy P Garcia Calavia*, University of East Anglia ; MJ Marin, University of East Anglia; I Chambrier, University of East Anglia; MJ Cook, University of East Anglia; DA Russell, University of East Anglia

Abstract: Phthalocyanines (Pcs) are widely used photosensitisers for photodynamic therapy (PDT). Such molecules predominantly produce singlet oxygen after light excitation. Hydrophobic Pcs have been shown to be ideal photosensitisers for PDT.(1) The main disadvantage of such Pcs is that their hydrophobicity presents problems for in vivo and in vitro delivery.(2) For this reason, numerous studies have focused on the use of nanoparticles as delivery vehicles.(3) Nanoparticles present further advantages as they can be additionally functionalised with targeting ligands that increase selectivity towards cancerous tissue.(2) In this study, gold nanoparticles (AuNPs; ca. 4 nm) were synthesised and functionalised with a mixed monolayer of polyethylene glycol and a zinc phthalocyanine (Pc). Two zinc phthalocyanines were explored. The difference between the two molecules was the length of the carbon chain that connects the Pc to the gold core. The chain was composed of either three (C3Pc) or eleven (C11Pc) carbon atoms. Fluorescence emission intensity was found to be higher for free C11Pc. Conversely, when the Pc was conjugated to AuNPs, higher fluorescence emission intensity was observed for C3Pc. These results open the possibility for an increased production of singlet oxygen and better cytotoxic effects. A comparison between C3Pc and C11Pc based AuNPs was studied in vitro using SK-BR-3 human breast adenocarcinoma cells, with and without the presence of a breast cancer specific targeting agent. Results on cell viability show a significant difference between C3Pc and C11Pc when they are not functionalised with the targeting ligand. Conversely, the functionalisation of the AuNPs with the specific anti-HER2 antibody leads to similar photodamage by both Pc systems. (1) Josefsen, L. B. et al., Theranostics 2012, 2, 916. (2) Obaid, G. et al., Angew. Chem., Int. Ed. 2012, 51, 6158. (3) Chaterjee, D. K. et al., Adv. Drug Delivery Rev. 2008, 60, 1627.

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