Dong Soo Hwang, Matthew J Harrington, Qingye Lu, Admir Masic, Hongbo Zeng, J Herbert Waite
Marine mussels utilize a variety of DOPA-rich proteins for purposes of underwater adhesion, as well as for creating hard and flexible surface coatings for their tough and stretchy byssal fibers. In the present study, moderately strong, yet reversible wet adhesion between the protective mussel coating protein, mcfp-1, and amorphous titania was measured with a surface force apparatus (SFA). In parallel, resonance Raman spectroscopy was employed to identify the presence of bidentate DOPA-Ti coordination bonds at the TiO(2)-protein interface, suggesting that catechol-TiO(2) complexation contributes to the observed reversible wet adhesion. These results have important implications for the design of protective coatings on TiO(2).
{"title":"Mussel foot protein-1 (mcfp-1) interaction with titania surfaces().","authors":"Dong Soo Hwang, Matthew J Harrington, Qingye Lu, Admir Masic, Hongbo Zeng, J Herbert Waite","doi":"10.1039/C2JM32439C","DOIUrl":"https://doi.org/10.1039/C2JM32439C","url":null,"abstract":"<p><p>Marine mussels utilize a variety of DOPA-rich proteins for purposes of underwater adhesion, as well as for creating hard and flexible surface coatings for their tough and stretchy byssal fibers. In the present study, moderately strong, yet reversible wet adhesion between the protective mussel coating protein, mcfp-1, and amorphous titania was measured with a surface force apparatus (SFA). In parallel, resonance Raman spectroscopy was employed to identify the presence of bidentate DOPA-Ti coordination bonds at the TiO(2)-protein interface, suggesting that catechol-TiO(2) complexation contributes to the observed reversible wet adhesion. These results have important implications for the design of protective coatings on TiO(2).</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 31","pages":"15530-15533"},"PeriodicalIF":0.0,"publicationDate":"2012-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM32439C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31006071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongyu Chen, Daniel C Colvin, Bin Qi, Thomas Moore, Jian He, O Thompson Mefford, Frank Alexis, John C Gore, Jeffrey N Anker
When X-rays irradiate radioluminescence nanoparticles, they generate visible and near infrared light that can penetrate through centimeters of tissue. X-ray luminescence tomography (XLT) maps the location of these radioluminescent contrast agents at high resolution by scanning a narrow X-ray beam through the tissue sample and collecting the luminescence at every position. Adding magnetic functionality to these radioluminescent particles would enable them to be guided, oriented, and heated using external magnetic fields, while their location and spectrum could be imaged with XLT and complementary magnetic resonance imaging. In this work, multifunctional monodispersed magnetic radioluminescent nanoparticles were developed as potential drug delivery carriers and radioluminescence imaging agents. The particles consisted of a spindle-shaped magnetic γ-Fe2O3 core and a radioluminescent europium-doped gadolinium oxide shell. Particles with solid iron oxide cores displayed saturation magnetizations consistent with their ~13% core volume, however, the iron oxide quenched their luminescence. In order to increase the luminescence, we partially etched the iron oxide core in oxalic acid while preserving the radioluminescent shell. The core size was controlled by the etching time which in turn affected the particles' luminescence and magnetic properties. Particles with intermediate core sizes displayed both strong magnetophoresis and luminescence properties. They also served as MRI contrast agents with relaxivities of up to 58 mM-1s-1 (r2) and 120 mM-1s-1 (r2*). These particles offer promising multimodal MRI/fluorescence/X-ray luminescence contrast agents. Our core-shell synthesis technique offers a flexible method to control particle size, shape, and composition for a wide range of biological applications of magnetic/luminescent nanoparticles.
当 X 射线照射放射发光纳米粒子时,它们会产生可见光和近红外线,这种光可以穿透几厘米厚的组织。X 射线发光断层扫描(XLT)通过扫描穿过组织样本的窄 X 射线束,收集每个位置的发光情况,从而以高分辨率绘制出这些放射性发光造影剂的位置图。为这些放射性发光粒子添加磁性功能后,就能利用外部磁场对它们进行引导、定向和加热,同时利用 XLT 和互补磁共振成像技术对它们的位置和光谱进行成像。这项研究开发了多功能单分散磁性辐射纳米粒子,作为潜在的药物输送载体和辐射成像剂。这些颗粒由纺锤形磁性 γ-Fe2O3 内核和掺杂铕的放射性氧化钆外壳组成。具有固体氧化铁内核的颗粒显示出与其约 13% 的内核体积相一致的饱和磁化,但氧化铁淬灭了它们的发光。为了增加发光,我们在草酸中部分蚀刻了氧化铁内核,同时保留了放射性发光外壳。内核大小受蚀刻时间的控制,而蚀刻时间又会影响颗粒的发光和磁性。具有中等内核尺寸的微粒显示出很强的磁性和发光特性。它们还可用作磁共振成像对比剂,弛豫度高达 58 mM-1s-1 (r2) 和 120 mM-1s-1 (r2*)。这些颗粒是很有前景的多模式核磁共振成像/荧光/X 射线发光对比剂。我们的核壳合成技术提供了一种灵活的方法来控制颗粒的大小、形状和成分,从而实现磁性/发光纳米颗粒的广泛生物应用。
{"title":"Magnetic and optical properties of multifunctional core-shell radioluminescence nanoparticles.","authors":"Hongyu Chen, Daniel C Colvin, Bin Qi, Thomas Moore, Jian He, O Thompson Mefford, Frank Alexis, John C Gore, Jeffrey N Anker","doi":"10.1039/C2JM15444G","DOIUrl":"10.1039/C2JM15444G","url":null,"abstract":"<p><p>When X-rays irradiate radioluminescence nanoparticles, they generate visible and near infrared light that can penetrate through centimeters of tissue. X-ray luminescence tomography (XLT) maps the location of these radioluminescent contrast agents at high resolution by scanning a narrow X-ray beam through the tissue sample and collecting the luminescence at every position. Adding magnetic functionality to these radioluminescent particles would enable them to be guided, oriented, and heated using external magnetic fields, while their location and spectrum could be imaged with XLT and complementary magnetic resonance imaging. In this work, multifunctional monodispersed magnetic radioluminescent nanoparticles were developed as potential drug delivery carriers and radioluminescence imaging agents. The particles consisted of a spindle-shaped magnetic γ-Fe<sub>2</sub>O<sub>3</sub> core and a radioluminescent europium-doped gadolinium oxide shell. Particles with solid iron oxide cores displayed saturation magnetizations consistent with their ~13% core volume, however, the iron oxide quenched their luminescence. In order to increase the luminescence, we partially etched the iron oxide core in oxalic acid while preserving the radioluminescent shell. The core size was controlled by the etching time which in turn affected the particles' luminescence and magnetic properties. Particles with intermediate core sizes displayed both strong magnetophoresis and luminescence properties. They also served as MRI contrast agents with relaxivities of up to 58 mM<sup>-1</sup>s<sup>-1</sup> (r<sub>2</sub>) and 120 mM<sup>-1</sup>s<sup>-1</sup> (r<sub>2</sub>*). These particles offer promising multimodal MRI/fluorescence/X-ray luminescence contrast agents. Our core-shell synthesis technique offers a flexible method to control particle size, shape, and composition for a wide range of biological applications of magnetic/luminescent nanoparticles.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 25","pages":"12802-12809"},"PeriodicalIF":0.0,"publicationDate":"2012-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918467/pdf/nihms490694.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32109469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-05-01Epub Date: 2012-03-14DOI: 10.1039/C2JM30258F
Hongguang Lu, Fengyu Su, Qian Mei, Yanqing Tian, Wenjing Tian, Roger H Johnson, Deirdre R Meldrum
Two new series of aggregation-induced emission (AIE) fluorophore-containing amphiphilic copolymers possessing the segments of a monomeric AIE fluorophore, N-(2-hydroxypropyl)methacrylamide (HPMA), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MATMA), and/or 2,2,2-trifluoroethyl methacrylate (TFEMA) were synthesized. Photophysical properties were investigated using UV-Vis absorbance and fluorescence spectrofluorometry. The increases of molar fractions of the hydrophobic AIE fluorophores and/or the trifluoroethyl moieties result in the higher quantum yields of the AIE fluorophores in the polymers. Using 1-mol% of AIE fluorophores with the tuning of molar fractions of TFEMA, 40% quantum yield was achieved, whereas only less than 10% quantum yield was obtained for the polymers without the TFEMA segments. The quantum yield difference indicates the importance of the fluorine segments for getting high quantum yields of the AIE fluorophores. These polymers were explored for fluorescent bioimaging using human brain glioblastoma U87MG and human esophagus premalignant CP-A cell lines. All the polymers are cell permeable and located in the cellular cytoplasma area. Cellular uptake was demonstrated to be through endocytosis, which is time and energy dependent. The polymers are non-cytotoxic to the two cell lines. Because the polymers contain (19)F segments, we studied the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of these polymers. T1 and T2 are the two important parameters for the evaluations of the capacity of these polymers for further applications in (19)F magnetic resonance imaging ((19)F MRI). Structure influence on T1 and T2, especially for T2, was observed. These new multifunctional materials are the first series of fluorinated polymers with AIE fluorophores for bioapplications.
{"title":"Using fluorine-containing amphiphilic random copolymers to manipulate the quantum yields of aggregation-induced emission fluorophores in aqueous solutions and the use of these polymers for fluorescent bioimaging.","authors":"Hongguang Lu, Fengyu Su, Qian Mei, Yanqing Tian, Wenjing Tian, Roger H Johnson, Deirdre R Meldrum","doi":"10.1039/C2JM30258F","DOIUrl":"10.1039/C2JM30258F","url":null,"abstract":"<p><p>Two new series of aggregation-induced emission (AIE) fluorophore-containing amphiphilic copolymers possessing the segments of a monomeric AIE fluorophore, N-(2-hydroxypropyl)methacrylamide (HPMA), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MATMA), and/or 2,2,2-trifluoroethyl methacrylate (TFEMA) were synthesized. Photophysical properties were investigated using UV-Vis absorbance and fluorescence spectrofluorometry. The increases of molar fractions of the hydrophobic AIE fluorophores and/or the trifluoroethyl moieties result in the higher quantum yields of the AIE fluorophores in the polymers. Using 1-mol% of AIE fluorophores with the tuning of molar fractions of TFEMA, 40% quantum yield was achieved, whereas only less than 10% quantum yield was obtained for the polymers without the TFEMA segments. The quantum yield difference indicates the importance of the fluorine segments for getting high quantum yields of the AIE fluorophores. These polymers were explored for fluorescent bioimaging using human brain glioblastoma U87MG and human esophagus premalignant CP-A cell lines. All the polymers are cell permeable and located in the cellular cytoplasma area. Cellular uptake was demonstrated to be through endocytosis, which is time and energy dependent. The polymers are non-cytotoxic to the two cell lines. Because the polymers contain (19)F segments, we studied the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of these polymers. T1 and T2 are the two important parameters for the evaluations of the capacity of these polymers for further applications in (19)F magnetic resonance imaging ((19)F MRI). Structure influence on T1 and T2, especially for T2, was observed. These new multifunctional materials are the first series of fluorinated polymers with AIE fluorophores for bioapplications.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 19","pages":"9890-9900"},"PeriodicalIF":0.0,"publicationDate":"2012-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565462/pdf/nihms408097.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31228828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lixin Liu, Hailong Zhou, Rui Cheng, Yu Chen, Yung-Chen Lin, Yongquan Qu, Jingwei Bai, Ivan A Ivanov, Gang Liu, Yu Huang, Xiangfeng Duan
Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical vapor deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric pressure chemical vapor deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH4 partial pressure, while the density of domains decreases with increasing growth temperature and is independent of the CH4 partial pressure. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm2 V-1 s-1 at room temperature.
{"title":"A systematic study of atmospheric pressure chemical vapor deposition growth of large-area monolayer graphene.","authors":"Lixin Liu, Hailong Zhou, Rui Cheng, Yu Chen, Yung-Chen Lin, Yongquan Qu, Jingwei Bai, Ivan A Ivanov, Gang Liu, Yu Huang, Xiangfeng Duan","doi":"10.1039/C1JM14272K","DOIUrl":"https://doi.org/10.1039/C1JM14272K","url":null,"abstract":"<p><p>Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical vapor deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric pressure chemical vapor deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH<sub>4</sub> partial pressure, while the density of domains decreases with increasing growth temperature and is independent of the CH<sub>4</sub> partial pressure. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm<sup>2</sup> V<sup>-1</sup> s<sup>-1</sup> at room temperature.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 4","pages":"1498-1503"},"PeriodicalIF":0.0,"publicationDate":"2012-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C1JM14272K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32828392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Justin T Koepsel, Patrick T Brown, Samuel G Loveland, Wan-Ju Li, William L Murphy
Self-assembled monolayers (SAMs) of alkanethiolates on gold are chemically defined substrates that can be used to evaluate the effects of an immobilized biomolecule. However, the types of biomolecules that can influence stem cell behavior are numerous and inter-related, and efficient experimental formats are a critical need. Here we employed a SAM array technology to investigate the effects of multiple, distinct peptides and peptide combinations on human mesenchymal stem cell (hMSC) behavior. Specifically, we characterized the conjugation of peptide mixtures to SAM arrays and then investigated the combined effects of a bone morphogenic protein receptor-binding peptide (BR-BP), a heparin proteoglycan-binding peptide (HPG-BP), and varied densities of the integrin-binding ligand Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) on hMSC surface coverage and alkaline phosphatase activity. Results indicate that an amine reactive fluorescent probe can be used to characterize peptide composition after immobilization in SAM array spots. Furthermore, hMSC response to BR-BP and HPG-BP is dependent on GRGDSP density and at day 7, hMSC alkaline phosphatase expression is highly dependent on GRGDSP density. Taken together, we demonstrate how a SAM array approach can be used to probe the combinatorial effects of multiple peptides and motivate further investigations into potential synergies between cell adhesion and other bioactive peptides.
{"title":"Combinatorial screening of chemically defined human mesenchymal stem cell culture substrates.","authors":"Justin T Koepsel, Patrick T Brown, Samuel G Loveland, Wan-Ju Li, William L Murphy","doi":"10.1039/C2JM32242K","DOIUrl":"https://doi.org/10.1039/C2JM32242K","url":null,"abstract":"<p><p>Self-assembled monolayers (SAMs) of alkanethiolates on gold are chemically defined substrates that can be used to evaluate the effects of an immobilized biomolecule. However, the types of biomolecules that can influence stem cell behavior are numerous and inter-related, and efficient experimental formats are a critical need. Here we employed a SAM array technology to investigate the effects of multiple, distinct peptides and peptide combinations on human mesenchymal stem cell (hMSC) behavior. Specifically, we characterized the conjugation of peptide mixtures to SAM arrays and then investigated the combined effects of a bone morphogenic protein receptor-binding peptide (BR-BP), a heparin proteoglycan-binding peptide (HPG-BP), and varied densities of the integrin-binding ligand Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) on hMSC surface coverage and alkaline phosphatase activity. Results indicate that an amine reactive fluorescent probe can be used to characterize peptide composition after immobilization in SAM array spots. Furthermore, hMSC response to BR-BP and HPG-BP is dependent on GRGDSP density and at day 7, hMSC alkaline phosphatase expression is highly dependent on GRGDSP density. Taken together, we demonstrate how a SAM array approach can be used to probe the combinatorial effects of multiple peptides and motivate further investigations into potential synergies between cell adhesion and other bioactive peptides.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 37","pages":"19474-19481"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM32242K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31683137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The synthesis and characterization of bare silica (4 nm in diameter) nanoparticle-attached meso-tetra(N-methyl-4-pyridyl)porphine (SiO(2)-TMPyP, 6 nm in diameter) are described for pH-controllable photosensitization. Distinguished from organosilanes, SiO(2) nanoparticles were functionalized as a potential quencher of triplet TMPyP and/or singlet oxygen ((1)O(2)) at alkaline pH, thereby turning off sensitizer photoactivity. In weak acidic solutions, TMPyP was released from SiO(2) surface for efficient production of (1)O(2). By monitoring (1)O(2) luminescence at 1270 nm, quantum yields of (1)O(2) production were found to be pH-dependent, dropping from ~ 0.45 in a pH range of 3-6 to 0.08 at pH 8-9, which is consistent with pH-dependent adsorption behavior of TMPyP on SiO(2) surface. These features make bare SiO(2)-attached cationic porphyrin a promising candidate for use in PDT for cancer treatment in which efficient (1)O(2) production at acidic pH and sensitizer deactivation at physiological pH are desirable. The enhanced therapeutic selectivity was confirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests and trypan blue exclusion tests of cell viability in breast cancer cell lines. Bimolecular quenching rate constants of (1)O(2) by free TMPyP, SiO(2) and SiO(2)-TMPyP nanoparticles were also determined.
{"title":"Enhanced Photodynamic Selectivity of Nano-Silica-Attached Porphyrins Against Breast Cancer Cells.","authors":"Wenbing Li, Wentong Lu, Zhen Fan, Xianchun Zhu, Aisha Reed, Brandon Newton, Yazhou Zhang, Shavelle Courtney, Papireddy T Tiyyagura, Shufang Li, Ebonie Butler, Hongtao Yu, Paresh C Ray, Ruomei Gao","doi":"10.1039/C2JM30897E","DOIUrl":"https://doi.org/10.1039/C2JM30897E","url":null,"abstract":"<p><p>The synthesis and characterization of bare silica (4 nm in diameter) nanoparticle-attached meso-tetra(N-methyl-4-pyridyl)porphine (SiO(2)-TMPyP, 6 nm in diameter) are described for pH-controllable photosensitization. Distinguished from organosilanes, SiO(2) nanoparticles were functionalized as a potential quencher of triplet TMPyP and/or singlet oxygen ((1)O(2)) at alkaline pH, thereby turning off sensitizer photoactivity. In weak acidic solutions, TMPyP was released from SiO(2) surface for efficient production of (1)O(2). By monitoring (1)O(2) luminescence at 1270 nm, quantum yields of (1)O(2) production were found to be pH-dependent, dropping from ~ 0.45 in a pH range of 3-6 to 0.08 at pH 8-9, which is consistent with pH-dependent adsorption behavior of TMPyP on SiO(2) surface. These features make bare SiO(2)-attached cationic porphyrin a promising candidate for use in PDT for cancer treatment in which efficient (1)O(2) production at acidic pH and sensitizer deactivation at physiological pH are desirable. The enhanced therapeutic selectivity was confirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests and trypan blue exclusion tests of cell viability in breast cancer cell lines. Bimolecular quenching rate constants of (1)O(2) by free TMPyP, SiO(2) and SiO(2)-TMPyP nanoparticles were also determined.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 25","pages":"12701-12708"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM30897E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31072649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-06-07DOI: 10.1039/C2JM32299D
Kathryn E Dekrafft, William S Boyle, Laurel M Burk, Otto Z Zhou, Wenbin Lin
Nanoscale metal-organic frameworks (NMOFs) of the UiO-66 structure containing high Zr (37 wt%) and Hf (57 wt%) content were synthesized and characterized, and their potential as contrast agents for X-ray computed tomography (CT) imaging was evaluated. Hf-NMOFs of different sizes were coated with silica and poly(ethylene glycol) (PEG) to enhance biocompatibility, and were used for in vivo CT imaging of mice, showing increased attenuation in the liver and spleen.
{"title":"Zr- and Hf-based nanoscale metal-organic frameworks as contrast agents for computed tomography.","authors":"Kathryn E Dekrafft, William S Boyle, Laurel M Burk, Otto Z Zhou, Wenbin Lin","doi":"10.1039/C2JM32299D","DOIUrl":"10.1039/C2JM32299D","url":null,"abstract":"<p><p>Nanoscale metal-organic frameworks (NMOFs) of the UiO-66 structure containing high Zr (37 wt%) and Hf (57 wt%) content were synthesized and characterized, and their potential as contrast agents for X-ray computed tomography (CT) imaging was evaluated. Hf-NMOFs of different sizes were coated with silica and poly(ethylene glycol) (PEG) to enhance biocompatibility, and were used for in vivo CT imaging of mice, showing increased attenuation in the liver and spleen.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 35","pages":"18139-18144"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3462458/pdf/nihms389678.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30963954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-09-07DOI: 10.1039/C2JM32466K
Jason Christopher Dyke, Kelly Jane Knight, Huaxing Zhou, Chi-Kai Chiu, Ching-Chang Ko, Wei You
Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N'-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, T(g), and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite.These HAp-Gemosil/P(LLA-co-PC)(AS) composites were subjected to mechanical and biological testing, and the results were compared with those from the HAp-Gemosil composites. This study revealed that incorporating a cross-linkable polymer served to increase the flexural strength of the composite by 50%, while maintaining the biocompatibility of HAp-Gemosil ceramics.
{"title":"An Investigation of Siloxane Cross-linked Hydroxyapatite-Gelatin/Copolymer Composites for Potential Orthopedic Applications().","authors":"Jason Christopher Dyke, Kelly Jane Knight, Huaxing Zhou, Chi-Kai Chiu, Ching-Chang Ko, Wei You","doi":"10.1039/C2JM32466K","DOIUrl":"https://doi.org/10.1039/C2JM32466K","url":null,"abstract":"Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N'-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, T(g), and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite.These HAp-Gemosil/P(LLA-co-PC)(AS) composites were subjected to mechanical and biological testing, and the results were compared with those from the HAp-Gemosil composites. This study revealed that incorporating a cross-linkable polymer served to increase the flexural strength of the composite by 50%, while maintaining the biocompatibility of HAp-Gemosil ceramics.","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 43","pages":"22888-22898"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM32466K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31036927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-02-27DOI: 10.1039/C2JM16633J
Yih Horng Tan, Jason A Davis, Kohki Fujikawa, N Vijaya Ganesh, Alexei V Demchenko, Keith J Stine
Nitrogen adsorption/desorption isotherms are used to investigate the Brunauer, Emmett, and Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size distribution of physically modified, thermally annealed, and octadecanethiol functionalized np-Au monoliths. We present the full adsorption-desorption isotherms for N(2) gas on np-Au, and observe type IV isotherms and type H1 hysteresis loops. The evolution of the np-Au under various thermal annealing treatments was examined using scanning electron microscopy (SEM). The images of both the exterior and interior of the thermally annealed np-Au show that the porosity of all free standing np-Au structures decreases as the heat treatment temperature increases. The modification of the np-Au surface with a self-assembled monolayer (SAM) of C(18)-SH (coverage of 2.94 × 10(14) molecules cm(-2) based from the decomposition of the C(18)-SH using thermogravimetric analysis (TGA)), was found to reduce the strength of the interaction of nitrogen gas with the np-Au surface, as reflected by a decrease in the 'C' parameter of the BET equation. From cyclic voltammetry studies, we found that the surface area of the np-Au monoliths annealed at elevated temperatures followed the same trend with annealing temperature as found in the BET surface area study and SEM morphology characterization. The study highlights the ability to control free-standing nanoporous gold monoliths with high surface area, and well-defined, tunable pore morphology.
氮气吸附/解吸等温线用于研究物理修饰、热退火和十八硫醇功能化的np-Au整体体的Brunauer, Emmett, and Teller (BET)表面积和Barrett-Joyner-Halenda (BJH)孔径分布。我们给出了N(2)气体在np-Au上的全吸附-解吸等温线,并观察到IV型等温线和H1型滞回线。利用扫描电子显微镜(SEM)研究了不同热处理条件下np-Au的演化过程。热退火后的np-Au的内部和外部图像表明,随着热处理温度的升高,所有独立的np-Au结构的孔隙率都减小。利用热重分析(TGA)对C(18)-SH进行分解,发现用C(18)-SH自组装单层(SAM)(覆盖面积为2.94 × 10(14)分子cm(-2))修饰np-Au表面,可以降低氮气与np-Au表面的相互作用强度,这反映在BET方程的“C”参数的降低上。从循环伏安法研究中,我们发现在高温下退火的np-Au单体的表面积与在BET表面积研究和SEM形貌表征中发现的趋势相同。该研究强调了控制具有高表面积、定义明确、可调孔隙形态的独立纳米孔金单体的能力。
{"title":"Surface area and pore size characteristics of nanoporous gold subjected to thermal, mechanical, or surface modification studied using gas adsorption isotherms, cyclic voltammetry, thermogravimetric analysis, and scanning electron microscopy.","authors":"Yih Horng Tan, Jason A Davis, Kohki Fujikawa, N Vijaya Ganesh, Alexei V Demchenko, Keith J Stine","doi":"10.1039/C2JM16633J","DOIUrl":"https://doi.org/10.1039/C2JM16633J","url":null,"abstract":"<p><p>Nitrogen adsorption/desorption isotherms are used to investigate the Brunauer, Emmett, and Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size distribution of physically modified, thermally annealed, and octadecanethiol functionalized np-Au monoliths. We present the full adsorption-desorption isotherms for N(2) gas on np-Au, and observe type IV isotherms and type H1 hysteresis loops. The evolution of the np-Au under various thermal annealing treatments was examined using scanning electron microscopy (SEM). The images of both the exterior and interior of the thermally annealed np-Au show that the porosity of all free standing np-Au structures decreases as the heat treatment temperature increases. The modification of the np-Au surface with a self-assembled monolayer (SAM) of C(18)-SH (coverage of 2.94 × 10(14) molecules cm(-2) based from the decomposition of the C(18)-SH using thermogravimetric analysis (TGA)), was found to reduce the strength of the interaction of nitrogen gas with the np-Au surface, as reflected by a decrease in the 'C' parameter of the BET equation. From cyclic voltammetry studies, we found that the surface area of the np-Au monoliths annealed at elevated temperatures followed the same trend with annealing temperature as found in the BET surface area study and SEM morphology characterization. The study highlights the ability to control free-standing nanoporous gold monoliths with high surface area, and well-defined, tunable pore morphology.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 14","pages":"6733-6745"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM16633J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30782125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-01-01Epub Date: 2012-09-13DOI: 10.1039/C2JM35334B
Carsten O Schirra, Angana Senpan, Ewald Roessl, Axel Thran, Allen J Stacy, Lina Wu, Roland Proska, Dipanjan Pan
Spectral CT is the newest advancement in CT imaging technology, which enhances traditional CT images with the capability to image and quantify certain elements based on their distinctive K-edge energies. K-edge imaging feature recognizes high accumulations of targeted elements and presents them as colorized voxels against the normal grayscale X-ray background offering promise to overcome the relatively low inherent contrast within soft tissue and distinguish the high attenuation of calcium from contrast enhanced targets. Towards this aim, second generation gold nanobeacons (GNB(2)), which incorporate at least five times more metal than the previous generation was developed. The particles were synthesized as lipid-encapsulated, vascularly constrained (>120 nm) nanoparticle incorporating tiny gold nanoparticles (2-4 nm) within a polysorbate core. The choice of core material dictated to achieve a higher metal loading. The particles were thoroughly characterized by physicochemical techniques. This study reports one of the earlier examples of spectral CT imaging with gold nanoparticles demonstrating the potential for targeted in vitro and in vivo imaging and eliminates calcium interference with CT. The use of statistical image reconstruction shows high SNR may allow dose reduction and/or faster scan times.
{"title":"Second Generation Gold Nanobeacons for Robust K-Edge Imaging with Multi-Energy CT.","authors":"Carsten O Schirra, Angana Senpan, Ewald Roessl, Axel Thran, Allen J Stacy, Lina Wu, Roland Proska, Dipanjan Pan","doi":"10.1039/C2JM35334B","DOIUrl":"https://doi.org/10.1039/C2JM35334B","url":null,"abstract":"<p><p>Spectral CT is the newest advancement in CT imaging technology, which enhances traditional CT images with the capability to image and quantify certain elements based on their distinctive K-edge energies. K-edge imaging feature recognizes high accumulations of targeted elements and presents them as colorized voxels against the normal grayscale X-ray background offering promise to overcome the relatively low inherent contrast within soft tissue and distinguish the high attenuation of calcium from contrast enhanced targets. Towards this aim, second generation gold nanobeacons (GNB(2)), which incorporate at least five times more metal than the previous generation was developed. The particles were synthesized as lipid-encapsulated, vascularly constrained (>120 nm) nanoparticle incorporating tiny gold nanoparticles (2-4 nm) within a polysorbate core. The choice of core material dictated to achieve a higher metal loading. The particles were thoroughly characterized by physicochemical techniques. This study reports one of the earlier examples of spectral CT imaging with gold nanoparticles demonstrating the potential for targeted in vitro and in vivo imaging and eliminates calcium interference with CT. The use of statistical image reconstruction shows high SNR may allow dose reduction and/or faster scan times.</p>","PeriodicalId":16297,"journal":{"name":"Journal of Materials Chemistry","volume":"22 43","pages":"23071-23077"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/C2JM35334B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31076878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}