The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Tatjana Paunesku - One of the best experts on this subject based on the ideXlab platform.
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cytotoxicity and dna cleavage with core shell nanocomposites functionalized by a kh domain dna binding peptide
Nanoscale, 2013Co-Authors: Remon Bazak, Jan Ressl, Sumita Raha, Beau Wanzer, Seddik Abdel Salam, Tatjana Paunesku, Caroline Doty, Samy Elwany, Gayle E. WoloschakAbstract:A nanoconjugate was composed of metal oxide nanoparticles decorated with peptides and fluorescent dye and tested for DNA cleavage following UV light activation. The peptide design was based on a DNA binding domain, the so called KH domain of the hnRNPK protein. This “KH peptide” enabled cellular uptake of Nanoconjugates and their entry into cell nuclei. The control nanoconjugate carried no peptide; it consisted only of the metal oxide nanoparticle prepared as Fe3O4@TiO2 nanocomposite and the fluorescent dye alizarin red S. These components of either construct are responsible for nanoconjugate activation by UV light and the resultant production of reactive oxygen species (ROS). Production of ROS at different subcellular locations causes damage to different components of cells: only Nanoconjugates inside cell nuclei can be expected to cause DNA cleavage. Degradation of cellular DNA with KH peptide decorated Nanoconjugates exceeded the DNA damage obtained from control, no-peptide nanoconjugate counterparts. Moreover, caspase activation and cell death were more extensive in the same cells.
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Uptake and Distribution of Ultrasmall Anatase TiO2 Alizarin Red S Nanoconjugates in Arabidopsis thaliana
Nano letters, 2010Co-Authors: Jasmina Kurepa, Tatjana Paunesku, Gayle E. Woloschak, Stefan Vogt, Hans Arora, Bryan M. Rabatic, M. Beau Wanzer, Jan A. SmalleAbstract:While few publications have documented the uptake of nanoparticles in plants, this is the first study describing uptake and distribution of the ultrasmall anatase TiO2 in the plant model system Arabidopsis. We modified the nanoparticle surface with Alizarin red S and sucrose and demonstrated that Nanoconjugates traversed cell walls, entered into plant cells, and accumulated in specific subcellular locations. Optical and X-ray fluorescence microscopy coregistered the Nanoconjugates in cell vacuoles and nuclei.
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labeling tio2 nanoparticles with dyes for optical fluorescence microscopy and determination of tio2 dna nanoconjugate stability
Small, 2009Co-Authors: Kenneth T Thurn, Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Eric Brown, Raymond C Bergan, Mohammed Aslam, Vinayak P. Dravid, Gayle E. WoloschakAbstract:Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA Nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The Nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA Nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the Nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA Nanoconjugates in malignant cells.
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gadolinium conjugated tio2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
Nanomedicine: Nanotechnology Biology and Medicine, 2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Jorg Maser, Kenneth T Thurn, Tianyi Ke, Rohan Dharmakumar, Nicole Mascheri, Aiguo Wu, Barbara Szolckowalska, Andrew C LarsonAbstract:Abstract Nanoconjugates composed of titanium dioxide (TiO 2 ) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection of cultured cancer cells with these Nanoconjugates showed them to be superior to the free contrast agent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently, T1-weighted contrast enhancements were observed in cells treated with Nanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time, Gd accumulation, and intracellular delivery may find its use in Gd neutron-capture cancer therapy.
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Methods for assessing DNA hybridization of peptide nucleic acid-titanium dioxide Nanoconjugates.
Analytical biochemistry, 2008Co-Authors: Eric Brown, Tatjana Paunesku, Kenneth T Thurn, Benjamin Haley, Jimmy Clark, Taisa Priester, Gayle E. WoloschakAbstract:We describe the synthesis of peptide nucleic acid (PNA)-titanium dioxide (TiO(2)) Nanoconjugates and several novel methods developed to investigate the DNA hybridization behaviors of these constructs. PNAs are synthetic DNA analogs resistant to degradation by cellular enzymes that hybridize to single-stranded DNA (ssDNA) with higher affinity than DNA oligonucleotides, invade double-stranded DNA (dsDNA), and form different PNA/DNA complexes. Previously, we developed a DNA-TiO(2) nanoconjugate capable of hybridizing to target DNA intracellularly in a sequence-specific manner with the ability to cleave DNA when excited by electromagnetic radiation but susceptible to degradation that may lower its intracellular targeting efficiency and retention time. PNA-TiO(2) Nanoconjugates described in the current article hybridize to target ssDNA, oligonucleotide dsDNA, and supercoiled plasmid DNA under physiological-like ionic and temperature conditions, enabling rapid, inexpensive, sequence-specific concentration of nucleic acids in vitro. When modified by the addition of imaging agents or peptides, hybridization capabilities of PNA-TiO(2) Nanoconjugates are enhanced, providing essential benefits for numerous in vitro and in vivo applications. The series of experiments shown here could not be done with either TiO(2)-DNA Nanoconjugates or PNAs alone, and the novel methods developed will benefit studies of numerous other nanoconjugate systems.
Stefan Vogt - One of the best experts on this subject based on the ideXlab platform.
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development of fe3o4 core tio2 shell nanocomposites and Nanoconjugates as a foundation for neuroblastoma radiosensitization
Cancer Nanotechnology, 2021Co-Authors: William Liu, Stefan Vogt, Barry Lai, Salida Mirzoeva, Ye Yuan, Junjing Deng, Si Chen, Karna Shah, Rahul Shroff, Reiner BleherAbstract:Neuroblastoma is the most common extracranial solid malignancy in childhood which, despite the current progress in radiotherapy and chemotherapy protocols, still has a high mortality rate in high risk tumors. Nanomedicine offers exciting and unexploited opportunities to overcome the shortcomings of conventional medicine. The photocatalytic properties of Fe3O4 core-TiO2 shell nanocomposites and their potential for cell specific targeting suggest that nanoconstructs produced using Fe3O4 core-TiO2 shell nanocomposites could be used to enhance radiation effects in neuroblastoma. In this study, we evaluated bare, metaiodobenzylguanidine (MIBG) and 3,4-Dihydroxyphenylacetic acid (DOPAC) coated Fe3O4@TiO2 as potential radiosensitizers for neuroblastoma in vitro. The uptake of bare and MIBG coated nanocomposites modestly sensitized neuroblastoma cells to ionizing radiation. Conversely, cells exposed to DOPAC coated nanocomposites exhibited a five-fold enhanced sensitivity to radiation, increased numbers of radiation induced DNA double-strand breaks, and apoptotic cell death. The addition of a peptide mimic of the epidermal growth factor (EGF) to Nanoconjugates coated with MIBG altered their intracellular distribution. Cryo X-ray fluorescence microscopy tomography of frozen hydrated cells treated with these Nanoconjugates revealed cytoplasmic as well as nuclear distribution of the nanoconstructs. The intracellular distribution pattern of different Nanoconjugates used in this study was different for different nanoconjugate surface molecules. Cells exposed to DOPAC covered Nanoconjugates showed the smallest nanoconjugate uptake, with the most prominent pattern of large intracellular aggregates. Interestingly, cells treated with this nanoconjugate also showed the most pronounced radiosensitization effect in combination with the external beam x-ray irradiation. Further studies are necessary to evaluate mechanistic basis for this increased radiosensitization effect. Preliminary studies with the nanoparticles carrying an EGF mimicking peptide showed that this approach to targeting could perhaps be combined with a different approach to radiosensitization – use of Nanoconjugates in combination with the radioactive iodine. Much additional work will be necessary in order to evaluate possible benefits of targeted Nanoconjugates carrying radionuclides.
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Uptake and Distribution of Ultrasmall Anatase TiO2 Alizarin Red S Nanoconjugates in Arabidopsis thaliana
Nano letters, 2010Co-Authors: Jasmina Kurepa, Tatjana Paunesku, Gayle E. Woloschak, Stefan Vogt, Hans Arora, Bryan M. Rabatic, M. Beau Wanzer, Jan A. SmalleAbstract:While few publications have documented the uptake of nanoparticles in plants, this is the first study describing uptake and distribution of the ultrasmall anatase TiO2 in the plant model system Arabidopsis. We modified the nanoparticle surface with Alizarin red S and sucrose and demonstrated that Nanoconjugates traversed cell walls, entered into plant cells, and accumulated in specific subcellular locations. Optical and X-ray fluorescence microscopy coregistered the Nanoconjugates in cell vacuoles and nuclei.
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labeling tio2 nanoparticles with dyes for optical fluorescence microscopy and determination of tio2 dna nanoconjugate stability
Small, 2009Co-Authors: Kenneth T Thurn, Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Eric Brown, Raymond C Bergan, Mohammed Aslam, Vinayak P. Dravid, Gayle E. WoloschakAbstract:Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA Nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The Nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA Nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the Nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA Nanoconjugates in malignant cells.
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gadolinium conjugated tio2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
Nanomedicine: Nanotechnology Biology and Medicine, 2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Jorg Maser, Kenneth T Thurn, Tianyi Ke, Rohan Dharmakumar, Nicole Mascheri, Aiguo Wu, Barbara Szolckowalska, Andrew C LarsonAbstract:Abstract Nanoconjugates composed of titanium dioxide (TiO 2 ) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection of cultured cancer cells with these Nanoconjugates showed them to be superior to the free contrast agent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently, T1-weighted contrast enhancements were observed in cells treated with Nanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time, Gd accumulation, and intracellular delivery may find its use in Gd neutron-capture cancer therapy.
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original article diagnosis gadolinium conjugated tio 2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Kenneth T Thurn, Rohan Dharmakumar, Nicole Mascheri, Barbara Szolckowalska, Andrew C Larson, Raymond C BerganAbstract:Nanoconjugates composed of titanium dioxide (TiO2) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection ofculturedcancercellswiththeseNanoconjugatesshowedthemtobesuperiortothefreecontrastagent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently,T1-weightedcontrast enhancementswere observedincellstreated withNanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time,Gdaccumulation,andintracellulardeliverymayfinditsuseinGdneutron-capturecancertherapy.
Kenneth T Thurn - One of the best experts on this subject based on the ideXlab platform.
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labeling tio2 nanoparticles with dyes for optical fluorescence microscopy and determination of tio2 dna nanoconjugate stability
Small, 2009Co-Authors: Kenneth T Thurn, Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Eric Brown, Raymond C Bergan, Mohammed Aslam, Vinayak P. Dravid, Gayle E. WoloschakAbstract:Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA Nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The Nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA Nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the Nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA Nanoconjugates in malignant cells.
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gadolinium conjugated tio2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
Nanomedicine: Nanotechnology Biology and Medicine, 2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Jorg Maser, Kenneth T Thurn, Tianyi Ke, Rohan Dharmakumar, Nicole Mascheri, Aiguo Wu, Barbara Szolckowalska, Andrew C LarsonAbstract:Abstract Nanoconjugates composed of titanium dioxide (TiO 2 ) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection of cultured cancer cells with these Nanoconjugates showed them to be superior to the free contrast agent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently, T1-weighted contrast enhancements were observed in cells treated with Nanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time, Gd accumulation, and intracellular delivery may find its use in Gd neutron-capture cancer therapy.
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Methods for assessing DNA hybridization of peptide nucleic acid-titanium dioxide Nanoconjugates.
Analytical biochemistry, 2008Co-Authors: Eric Brown, Tatjana Paunesku, Kenneth T Thurn, Benjamin Haley, Jimmy Clark, Taisa Priester, Gayle E. WoloschakAbstract:We describe the synthesis of peptide nucleic acid (PNA)-titanium dioxide (TiO(2)) Nanoconjugates and several novel methods developed to investigate the DNA hybridization behaviors of these constructs. PNAs are synthetic DNA analogs resistant to degradation by cellular enzymes that hybridize to single-stranded DNA (ssDNA) with higher affinity than DNA oligonucleotides, invade double-stranded DNA (dsDNA), and form different PNA/DNA complexes. Previously, we developed a DNA-TiO(2) nanoconjugate capable of hybridizing to target DNA intracellularly in a sequence-specific manner with the ability to cleave DNA when excited by electromagnetic radiation but susceptible to degradation that may lower its intracellular targeting efficiency and retention time. PNA-TiO(2) Nanoconjugates described in the current article hybridize to target ssDNA, oligonucleotide dsDNA, and supercoiled plasmid DNA under physiological-like ionic and temperature conditions, enabling rapid, inexpensive, sequence-specific concentration of nucleic acids in vitro. When modified by the addition of imaging agents or peptides, hybridization capabilities of PNA-TiO(2) Nanoconjugates are enhanced, providing essential benefits for numerous in vitro and in vivo applications. The series of experiments shown here could not be done with either TiO(2)-DNA Nanoconjugates or PNAs alone, and the novel methods developed will benefit studies of numerous other nanoconjugate systems.
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original article diagnosis gadolinium conjugated tio 2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Kenneth T Thurn, Rohan Dharmakumar, Nicole Mascheri, Barbara Szolckowalska, Andrew C Larson, Raymond C BerganAbstract:Nanoconjugates composed of titanium dioxide (TiO2) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection ofculturedcancercellswiththeseNanoconjugatesshowedthemtobesuperiortothefreecontrastagent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently,T1-weightedcontrast enhancementswere observedincellstreated withNanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time,Gdaccumulation,andintracellulardeliverymayfinditsuseinGdneutron-capturecancertherapy.
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intracellular distribution of tio2 dna oligonucleotide Nanoconjugates directed to nucleolus and mitochondria indicates sequence specificity
Nano Letters, 2007Co-Authors: Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Natasa Stojicevic, Kenneth T Thurn, Clodia Osipo, Hong Liu, D Legnini, Zhou WangAbstract:Deoxyribonucleic acid (DNA) oligonucleotides hybridize to matching DNA sequences in cells, as established in the literature, depending on active transcription of the target sequence and local molarity of the oligonucleotide. We investigated the intracellular distribution of Nanoconjugates composed of DNA oligonucleotides attached to TiO2 nanoparticles, thus creating a locally increased concentration of the oligonucleotide. Two types of Nanoconjugates, with oligonucleotides matching mitochondrial or nucleolar DNA, were specifically retained in mitochondria or nucleoli.
Jorg Maser - One of the best experts on this subject based on the ideXlab platform.
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labeling tio2 nanoparticles with dyes for optical fluorescence microscopy and determination of tio2 dna nanoconjugate stability
Small, 2009Co-Authors: Kenneth T Thurn, Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Eric Brown, Raymond C Bergan, Mohammed Aslam, Vinayak P. Dravid, Gayle E. WoloschakAbstract:Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA Nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The Nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA Nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the Nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA Nanoconjugates in malignant cells.
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gadolinium conjugated tio2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
Nanomedicine: Nanotechnology Biology and Medicine, 2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Jorg Maser, Kenneth T Thurn, Tianyi Ke, Rohan Dharmakumar, Nicole Mascheri, Aiguo Wu, Barbara Szolckowalska, Andrew C LarsonAbstract:Abstract Nanoconjugates composed of titanium dioxide (TiO 2 ) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection of cultured cancer cells with these Nanoconjugates showed them to be superior to the free contrast agent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently, T1-weighted contrast enhancements were observed in cells treated with Nanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time, Gd accumulation, and intracellular delivery may find its use in Gd neutron-capture cancer therapy.
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original article diagnosis gadolinium conjugated tio 2 dna oligonucleotide Nanoconjugates show prolonged intracellular retention period and t1 weighted contrast enhancement in magnetic resonance images
2008Co-Authors: Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Kenneth T Thurn, Rohan Dharmakumar, Nicole Mascheri, Barbara Szolckowalska, Andrew C Larson, Raymond C BerganAbstract:Nanoconjugates composed of titanium dioxide (TiO2) nanoparticles, DNA oligonucleotides, and a gadolinium (Gd) contrast agent were synthesized for use in magnetic resonance imaging. Transfection ofculturedcancercellswiththeseNanoconjugatesshowedthemtobesuperiortothefreecontrastagent of the same formulation with regard to intracellular accumulation, retention, and subcellular localization. Our results have shown that 48 hours after treatment, the concentration of Gd in nanoconjugate-treated cells was 1000-fold higher than in cells treated with contrast agent alone. Consequently,T1-weightedcontrast enhancementswere observedincellstreated withNanoconjugates but not in cells treated by the contrast agent alone. This type of nanoconjugate with increased retention time,Gdaccumulation,andintracellulardeliverymayfinditsuseinGdneutron-capturecancertherapy.
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intracellular distribution of tio2 dna oligonucleotide Nanoconjugates directed to nucleolus and mitochondria indicates sequence specificity
Nano Letters, 2007Co-Authors: Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Natasa Stojicevic, Kenneth T Thurn, Clodia Osipo, Hong Liu, D Legnini, Zhou WangAbstract:Deoxyribonucleic acid (DNA) oligonucleotides hybridize to matching DNA sequences in cells, as established in the literature, depending on active transcription of the target sequence and local molarity of the oligonucleotide. We investigated the intracellular distribution of Nanoconjugates composed of DNA oligonucleotides attached to TiO2 nanoparticles, thus creating a locally increased concentration of the oligonucleotide. Two types of Nanoconjugates, with oligonucleotides matching mitochondrial or nucleolar DNA, were specifically retained in mitochondria or nucleoli.
Gayle E. Woloschak - One of the best experts on this subject based on the ideXlab platform.
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cytotoxicity and dna cleavage with core shell nanocomposites functionalized by a kh domain dna binding peptide
Nanoscale, 2013Co-Authors: Remon Bazak, Jan Ressl, Sumita Raha, Beau Wanzer, Seddik Abdel Salam, Tatjana Paunesku, Caroline Doty, Samy Elwany, Gayle E. WoloschakAbstract:A nanoconjugate was composed of metal oxide nanoparticles decorated with peptides and fluorescent dye and tested for DNA cleavage following UV light activation. The peptide design was based on a DNA binding domain, the so called KH domain of the hnRNPK protein. This “KH peptide” enabled cellular uptake of Nanoconjugates and their entry into cell nuclei. The control nanoconjugate carried no peptide; it consisted only of the metal oxide nanoparticle prepared as Fe3O4@TiO2 nanocomposite and the fluorescent dye alizarin red S. These components of either construct are responsible for nanoconjugate activation by UV light and the resultant production of reactive oxygen species (ROS). Production of ROS at different subcellular locations causes damage to different components of cells: only Nanoconjugates inside cell nuclei can be expected to cause DNA cleavage. Degradation of cellular DNA with KH peptide decorated Nanoconjugates exceeded the DNA damage obtained from control, no-peptide nanoconjugate counterparts. Moreover, caspase activation and cell death were more extensive in the same cells.
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Uptake and Distribution of Ultrasmall Anatase TiO2 Alizarin Red S Nanoconjugates in Arabidopsis thaliana
Nano letters, 2010Co-Authors: Jasmina Kurepa, Tatjana Paunesku, Gayle E. Woloschak, Stefan Vogt, Hans Arora, Bryan M. Rabatic, M. Beau Wanzer, Jan A. SmalleAbstract:While few publications have documented the uptake of nanoparticles in plants, this is the first study describing uptake and distribution of the ultrasmall anatase TiO2 in the plant model system Arabidopsis. We modified the nanoparticle surface with Alizarin red S and sucrose and demonstrated that Nanoconjugates traversed cell walls, entered into plant cells, and accumulated in specific subcellular locations. Optical and X-ray fluorescence microscopy coregistered the Nanoconjugates in cell vacuoles and nuclei.
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labeling tio2 nanoparticles with dyes for optical fluorescence microscopy and determination of tio2 dna nanoconjugate stability
Small, 2009Co-Authors: Kenneth T Thurn, Tatjana Paunesku, Stefan Vogt, Barry Lai, Jorg Maser, Eric Brown, Raymond C Bergan, Mohammed Aslam, Vinayak P. Dravid, Gayle E. WoloschakAbstract:Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO2) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO2-DNA Nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The Nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO2 nanoparticles and TiO2-DNA Nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO2 nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the Nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO2-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO2-DNA Nanoconjugates in malignant cells.
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Methods for assessing DNA hybridization of peptide nucleic acid-titanium dioxide Nanoconjugates.
Analytical biochemistry, 2008Co-Authors: Eric Brown, Tatjana Paunesku, Kenneth T Thurn, Benjamin Haley, Jimmy Clark, Taisa Priester, Gayle E. WoloschakAbstract:We describe the synthesis of peptide nucleic acid (PNA)-titanium dioxide (TiO(2)) Nanoconjugates and several novel methods developed to investigate the DNA hybridization behaviors of these constructs. PNAs are synthetic DNA analogs resistant to degradation by cellular enzymes that hybridize to single-stranded DNA (ssDNA) with higher affinity than DNA oligonucleotides, invade double-stranded DNA (dsDNA), and form different PNA/DNA complexes. Previously, we developed a DNA-TiO(2) nanoconjugate capable of hybridizing to target DNA intracellularly in a sequence-specific manner with the ability to cleave DNA when excited by electromagnetic radiation but susceptible to degradation that may lower its intracellular targeting efficiency and retention time. PNA-TiO(2) Nanoconjugates described in the current article hybridize to target ssDNA, oligonucleotide dsDNA, and supercoiled plasmid DNA under physiological-like ionic and temperature conditions, enabling rapid, inexpensive, sequence-specific concentration of nucleic acids in vitro. When modified by the addition of imaging agents or peptides, hybridization capabilities of PNA-TiO(2) Nanoconjugates are enhanced, providing essential benefits for numerous in vitro and in vivo applications. The series of experiments shown here could not be done with either TiO(2)-DNA Nanoconjugates or PNAs alone, and the novel methods developed will benefit studies of numerous other nanoconjugate systems.
