@article{sahin_vairaprakash_borbas_balasubramanian_lindsey_2015, title={Hydrophilic bioconjugatable trans-AB-porphyrins and peptide conjugates}, volume={19}, ISSN={["1099-1409"]}, DOI={10.1142/s1088424615500121}, abstractNote={ Porphyrins bearing a single bioconjugatable group and a single water-solubilization motif in a trans-AB-architecture (with no other substituents) provide a compact design of value for studies in diverse disciplines. Established synthetic methods have been employed to prepare four new free base porphyrins and one Mn ( III ) chelate. The hydrophilic motif includes 4-N-methylpyridinium, 2,4,6-tris(carboxymethoxy)phenyl, 2,6-bis(phosphonomethoxy)phenyl, and carboxy; the bioconjugatable unit includes carboxy, maleimido, and N-hydroxysuccinimido (NHS) ester. Bioconjugation experiments with a protected porphyrin-diphosphate or unprotected porphyrin-diphosphonate were examined in organic solution or water, respectively. Both approaches were employed to conjugate to the ε-amino group of Lys11 in AcKPV- NH 2, a tripeptide fragment [ Ac -α-MSH(11-13)- NH 2] of melanocyte stimulating hormone, yielding porphyrin-peptide conjugates. }, number={5}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, author={Sahin, Tuba and Vairaprakash, Pothiappan and Borbas, K. Eszter and Balasubramanian, Thiagarajan and Lindsey, Jonathan S.}, year={2015}, month={May}, pages={663–678} }
 @article{huang_mroz_zhiyentayev_sharma_balasubramanian_ruzie_krayer_fan_borbas_yang_et al._2010, title={In Vitro Photodynamic Therapy and Quantitative Structure-Activity Relationship Studies with Stable Synthetic Near-Infrared-Absorbing Bacteriochlorin Photosensitizers}, volume={53}, ISSN={["1520-4804"]}, DOI={10.1021/jm901908s}, abstractNote={Photodynamic therapy (PDT) is a rapidly developing approach to treating cancer that combines harmless visible and near-infrared light with a nontoxic photoactivatable dye, which upon encounter with molecular oxygen generates the reactive oxygen species that are toxic to cancer cells. Bacteriochlorins are tetrapyrrole compounds with two reduced pyrrole rings in the macrocycle. These molecules are characterized by strong absorption features from 700 to >800 nm, which enable deep penetration into tissue. This report describes testing of 12 new stable synthetic bacteriochlorins for PDT activity. The 12 compounds possess a variety of peripheral substituents and are very potent in killing cancer cells in vitro after illumination. Quantitative structure-activity relationships were derived, and subcellular localization was determined. The most active compounds have both low dark toxicity and high phototoxicity. This combination together with near-infrared absorption gives these bacteriochlorins great potential as photosensitizers for treatment of cancer.}, number={10}, journal={JOURNAL OF MEDICINAL CHEMISTRY}, author={Huang, Ying-Ying and Mroz, Pawel and Zhiyentayev, Timur and Sharma, Sulbha K. and Balasubramanian, Thiagarajan and Ruzie, Christian and Krayer, Michael and Fan, Dazhong and Borbas, K. Eszter and Yang, Eunkyung and et al.}, year={2010}, month={May}, pages={4018–4027} }
 @article{mroz_huang_szokalska_zhiyentayev_janjua_nifli_sherwood_ruzie_borbas_fan_et al._2010, title={Stable synthetic bacteriochlorins overcome the resistance of melanoma to photodynamic therapy}, volume={24}, ISSN={["0892-6638"]}, DOI={10.1096/fj.09-152587}, abstractNote={Cutaneous malignant melanoma remains a therapeutic challenge, and patients with advanced disease have limited survival. Photodynamic therapy (PDT) has been successfully used to treat many malignancies, and it may show promise as an antimelanoma modality. However, high melanin levels in melanomas can adversely affect PDT effectiveness. Herein the extent of melanin contribution to melanoma resistance to PDT was investigated in a set of melanoma cell lines that markedly differ in the levels of pigmentation;3 new bacteriochlorins successfully overcame the resistance. Cell killing studies determined that bacteriochlorins are superior at (LD50≈0.1 µM) when compared with controls such as the FDA‐approved Photofrin (LD50≈10 µM) and clinically tested LuTex (LD50≈=1 µM). The melanin content affects PDT effectiveness, but the degree of reduction is significantly lower for bacteriochlorins than for Photofrin. Microscopy reveals that the least effective bacteriochlorin localizes predominantly in lysosomes, while the most effective one preferentially accumulates in mitochondria. Interestingly all bacteriochlorins accumulate in melanosomes, and subsequent illumination leads to melanosomal damage shown by electron microscopy. Fluorescent probes show that the most effective bacteriochlorin produces significantly higher levels of hydroxyl radicals, and this is consistent with the redox properties suggested by molecular‐orbital calculations. The best in vitro performing bacteriochlorin was tested in vivo in a mouse melanoma model using spectrally resolved fluorescence imaging and provided significant survival advantage with 20% of cures (P<0.01).—Mroz, P., Huang, Y.‐Y., Szokalska, A., Zhiyentayev, T., Janjua, S., Nifli, A.‐P., Sherwood, M. E., Ruzié, C., Borbas, K. E., Fan, D., Krayer, M., Balasubramanian, T., Yang, E., Kee, H. L., Kirmaier, C., Diers, J. R., Bocian, D. F., Holten, D., Lindsey, J. S., Hamblin, M. R. Stable synthetic bacteriochlorins overcome the resistance of melanoma to photodynamic therapy. FASEB J. 24, 3160–3170 (2010). www.fasebj.org}, number={9}, journal={FASEB JOURNAL}, author={Mroz, Pawel and Huang, Ying-Ying and Szokalska, Angelika and Zhiyentayev, Timur and Janjua, Sahar and Nifli, Artemissia-Phoebe and Sherwood, Margaret E. and Ruzie, Christian and Borbas, K. Eszter and Fan, Dazhong and et al.}, year={2010}, month={Sep}, pages={3160–3170} }
 @article{borbas_kee_holten_lindsey_2008, title={A compact water-soluble porphyrin bearing an iodoacetamido bioconjugatable site}, volume={6}, ISSN={["1477-0539"]}, DOI={10.1039/b715072e}, abstractNote={A broad range of applications requires access to porphyrins that are compact, water-soluble, and bioconjugatable. A symmetrically branched hydrocarbon chain ('swallowtail') bearing polar end groups imparts high (>10 mM) aqueous solubility upon incorporation at one of the meso positions of a trans-AB-porphyrin. Two such swallowtail-porphyrins (1a, 1b) equipped with a conjugatable group (carboxylic acid, bromophenyl) have been prepared previously. The synthesis of three new water-soluble trans-AB-porphyrins is reported, where each porphyrin bears a diphosphonate-terminated swallowtail group and an amino (2a), acetamido (2b), or iodoacetamido (2c) group. The amine affords considerable versatility for functionalization. The iodoacetamide provides a sulfhydryl-reactive site for bioconjugation. Porphyrins were fully characterized in aqueous solution by 1H NMR spectroscopy (in D2O), ESI-MS, static absorption spectroscopy, and static and time-resolved fluorescence spectroscopy. Porphyrins 2a-2c exhibit characteristic porphyrin absorption and emission bands in aqueous solution, with a strong, sharp absorption band in the blue region (approximately 401 nm) and emission in the red region (approximately 624, 686 nm). Porphyrin 2b in aqueous phosphate buffer or phosphate-buffered saline solution exhibits a fluorescence quantum yield of approximately 0.04 and an excited singlet-state lifetime of approximately 11 ns. Collectively, the facile synthesis, amenability to bioconjugation, large spacing between the main absorption and fluorescence features, and long singlet excited-state lifetime make this molecular design quite attractive for a range of biomedical applications.}, number={1}, journal={ORGANIC & BIOMOLECULAR CHEMISTRY}, author={Borbas, K. Eszter and Kee, Hooi Ling and Holten, Dewey and Lindsey, Jonathan S.}, year={2008}, pages={187–194} }
 @article{borbas_chandrashaker_muthiah_kee_holten_lindsey_2008, title={Design, synthesis, and photophysical characterization of water-soluble chlorins}, volume={73}, ISSN={["1520-6904"]}, DOI={10.1021/jo7026728}, abstractNote={The use of chlorins as photosensitizers or fluorophores in a range of biological applications requires facile provisions for imparting high water solubility. Two free base chlorins have been prepared wherein each chlorin bears a geminal dimethyl group in the reduced ring and a water-solubilizing unit at the chlorin 10-position. In one design (FbC1-PO3H2), the water-solubilizing unit is a 1,5-diphosphonopent-3-yl ("swallowtail") unit, which has previously been used to good effect with porphyrins. In the other design (FbC2-PO3H2), the water-solubilizing unit is a 2,6-bis(phosphonomethoxy)phenyl unit. Two complementary routes were developed for preparing FbC2-PO3H2 that entail introduction of the protected phosphonate moieties either in the Eastern-half precursor to the chlorin or by derivatization of an intact chlorin. Water-solubilization is achieved in the last step of each synthesis upon removal of the phosphonate protecting groups. The chlorins FbC1-PO3H2 and FbC2-PO3H2 are highly water-soluble (>10 mM) as shown by 1H NMR spectroscopy (D2O) and UV-vis absorption spectroscopy. The photophysical properties of the water-soluble chlorins in phosphate-buffered saline solution (pH 7.4) at room temperature were investigated using static and time-resolved absorption and fluorescence spectroscopic techniques. Each chlorin exhibits dominant absorption bands in the blue and the red region (lambda = 398, 626 nm), a modest fluorescence yield (Phi f approximately 0.11), a long singlet excited-state lifetime (tau = 7.5 ns), and a high yield of intersystem crossing to give the triplet state (Phi isc = 0.9). The properties of the water-soluble chlorins in aqueous media are comparable to those of hydrophobic chlorins in toluene. The high aqueous solubility combined with the attractive photophysical properties make these compounds suitable for a wide range of biomedical applications.}, number={8}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Borbas, K. Eszter and Chandrashaker, Vanampally and Muthiah, Chinnasamy and Kee, Hooi Ling and Holten, Dewey and Lindsey, Jonathan S.}, year={2008}, month={Apr}, pages={3145–3158} }
 @article{yao_borbas_lindsey_2008, title={Soluble precipitable porphyrins for use in targeted molecular brachytherapy}, volume={32}, ISSN={["1369-9261"]}, DOI={10.1039/b714127k}, abstractNote={In a new therapy that aims to concentrate and immobilize therapeutic radionuclides in nanoscale assemblies within solid tumors, a soluble precipitable reagent (SPR) is administered as the radionuclide carrier and is converted to non-diffusible precipitate by an enzyme located in tumor tissues. To meet the objective of such an SPR, we have prepared and examined a class of porphyrin–alkyldiphosphates that are soluble in aqueous solution and that are rendered insoluble upon removal of the two phosphate groups. The porphyrins examined herein are of the trans-AB architecture wherein the substituents are a bis(dihydroxyphosphoryloxy)alkyl group and a phenyl (or p-bromophenyl) group. Provisions for later incorporation of radionuclides have been established by preparation of the analogous copper chelate or the meso-iodo free-base porphyrin. Altogether, four porphyrins bearing a bis(dihydroxyphosphoryloxy)alkyl group were examined and found to exhibit satisfactory solubility in water (>1 mM). Dephosphorylation reactions have been carried out in vitro using the enzyme shrimp alkaline phosphatase. In each case, enzyme-induced precipitation was observed. The soluble-to-insoluble conversion has been examined by visual inspection, absorption spectroscopy, electrospray ionization mass spectrometry, and nephelometry using non-radiolabeled porphyrins.}, number={3}, journal={NEW JOURNAL OF CHEMISTRY}, author={Yao, Zhen and Borbas, K. Eszter and Lindsey, Jonathan S.}, year={2008}, pages={436–451} }
 @article{borbas_ruzie_lindsey_2008, title={Swallowtail bacteriochlorins. Lipophilic absorbers for the near-infrared}, volume={10}, ISSN={["1523-7060"]}, DOI={10.1021/ol800436u}, abstractNote={Bacteriochlorins absorb strongly in the near-infrared spectral region and hence are ideally suited for diverse photomedical applications, yet naturally occurring bacteriochlorins have limited stability and synthetic malleability. A de novo route has been exploited to prepare synthetic bacteriochlorins that bear a geminal dimethyl group in each pyrroline ring for stability and a symmetrically branched 1,5-dimethoxypentyl group attached to each pyrrole ring for solubility in lipophilic media.}, number={10}, journal={ORGANIC LETTERS}, author={Borbas, K. Eszter and Ruzie, Christian and Lindsey, Jonathan S.}, year={2008}, month={May}, pages={1931–1934} }
 @article{bodi_borbas_bruce_2007, title={Near IR-emitting DNA-probes exploiting stepwise energy transfer processes}, number={38}, journal={Dalton Transactions (Cambridge, England : 2003)}, author={Bodi, A. and Borbas, K. E. and Bruce, J. I.}, year={2007}, pages={4352–4358} }
 @article{borbas_mroz_hamblin_lindsey_2006, title={Bioconjugatable porphyrins bearing a compact swallowtail motif for water solubility}, volume={17}, ISSN={["1043-1802"]}, DOI={10.1021/bc050337w}, abstractNote={A broad range of applications requires access to water-soluble, bioconjugatable porphyrins. Branched alkyl groups attached at the branching site to the porphyrin meso position are known to impart high organic solubility. Such "swallowtail" motifs bearing a polar group (hydroxy, dihydroxyphosphoryl, dihydroxyphosphoryloxy) at the terminus of each branch have now been incorporated at a meso site in trans-AB-porphyrins. The incorporation of the swallowtail motif relies on rational synthetic methods whereby a 1,9-bis(N-propylimino)dipyrromethane (bearing a bioconjugatable tether at the 5-position) is condensed with a dipyrromethane (bearing a protected 1,5-dihydroxypent-3-yl unit at the 5-position). The two hydroxy groups in the swallowtail motif of each of the resulting zinc porphyrins can be transformed to the corresponding diphosphate or diphosphonate product. A 4-(carboxymethyloxy)phenyl group provides the bioconjugatable tether. The six such porphyrins reported here are highly water-soluble (> or =20 mM at room temperature in water at pH 7) as determined by visual inspection, UV-vis absorption spectroscopy, or 1H NMR spectroscopy. Covalent attachment was carried out in aqueous solution with the unprotected porphyrin diphosphonate and a monoclonal antibody against the T-cell receptor CD3epsilon. The resulting conjugate performed comparably to a commercially available fluorescein isothiocyanate-labeled antibody with Jurkat cells in flow cytometry and fluorescence microscopy assays. Taken together, this work enables preparation of useful quantities of water-soluble, bioconjugatable porphyrins in a compact architecture for applications in the life sciences.}, number={3}, journal={BIOCONJUGATE CHEMISTRY}, author={Borbas, K. Eszter and Mroz, Pawel and Hamblin, Michael R. and Lindsey, Jonathan S.}, year={2006}, month={May}, pages={638–653} }
 @article{bhaumik_yao_borbas_taniguchi_lindsey_2006, title={Masked imidazolyl-dipyrromethanes in the synthesis of imidazole-substituted porphyrins}, volume={71}, ISSN={["0022-3263"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33750879603&partnerID=MN8TOARS}, DOI={10.1021/jo061461r}, abstractNote={Imidazole-substituted metalloporphyrins are valuable for studies of self-assembly and for applications where water solubility is required. Rational syntheses of porphyrins bearing one or two imidazol-2-yl or imidazol-4-yl groups at the meso positions have been developed. The syntheses employ dipyrromethanes, 1-acyldipyrromethanes, and 1,9-diacyldipyrromethanes bearing an imidazole group at the 5-position. The polar, reactive imidazole unit was successfully masked by use of (1) the 2-(trimethylsilyl)ethoxymethyl (SEM) group at the imidazole pyrrolic nitrogen, and (2) a dialkylboron motif bound to the pyrrole of the dipyrromethane and coordinated to the imidazole imino nitrogen. The nonpolar nature of such doubly masked imidazolyl-dipyrromethanes facilitated handling. Selected masked dipyrromethanes were characterized by 11B and 15N NMR spectroscopy. Five distinct methods were examined to obtain trans-A2B2-, trans-AB2C-, and trans-AB-porphyrins. Each porphyrin contained one or two SEM-protected imidazole units. The SEM group could be removed with TBAF or HCl. Two zinc(II) porphyrins and a palladium(II) porphyrin bearing a single imidazole moiety were prepared and subjected to alkylation (with ethyl iodide, 1,3-propane sultone, or 1,4-butane sultone) to give water-soluble imidazolium- porphyrins. This work establishes the foundation for the rational synthesis of a variety of porphyrins containing imidazole units.}, number={23}, journal={JOURNAL OF ORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Bhaumik, Jayeeta and Yao, Zhen and Borbas, K. Eszter and Taniguchi, Masahiko and Lindsey, Jonathan S.}, year={2006}, month={Nov}, pages={8807–8817} }