1
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Yeh PY, Chen JY, Shen MY, Che TF, Lim SC, Wang J, Tsai WS, Frank CW, Huang CJ, Chang YC. Liposome-tethered supported lipid bilayer platform for capture and release of heterogeneous populations of circulating tumor cells. J Mater Chem B 2023; 11:8159-8169. [PMID: 37313622 DOI: 10.1039/d3tb00547j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Because of scarcity, vulnerability, and heterogeneity in the population of circulating tumor cells (CTCs), the CTC isolation system relying on immunoaffinity interaction exhibits inconsistent efficiencies for all types of cancers and even CTCs with different phenotypes in individuals. Moreover, releasing viable CTCs from an isolation system is of importance for molecular analysis and drug screening in precision medicine, which remains a challenge for current systems. In this work, a new CTC isolation microfluidic platform was developed and contains a coating of the antibody-conjugated liposome-tethered-supported lipid bilayer in a developed chaotic-mixing microfluidic system, referred to as the "LIPO-SLB" platform. The biocompatible, soft, laterally fluidic, and antifouling properties of the LIPO-SLB platform offer high CTC capture efficiency, viability, and selectivity. We successfully demonstrated the capability of the LIPO-SLB platform to recapitulate different cancer cell lines with different antigen expression levels. In addition, the captured CTCs in the LIPO-SLB platform can be detached by air foam to destabilize the physically assembled bilayer structures due to a large water/air interfacial area and strong surface tension. More importantly, the LIPO-SLB platform was constructed and used for the verification of clinical samples from 161 patients with different primary cancer types. The mean values of both single CTCs and CTC clusters correlated well with the cancer stages. Moreover, a considerable number of CTCs were isolated from patients' blood samples in the early/localized stages. The clinical validation demonstrated the enormous potential of the universal LIPO-SLB platform as a tool for prognostic and predictive purposes in precision medicine.
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Affiliation(s)
- Po-Ying Yeh
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Jia-Yang Chen
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Mo-Yuan Shen
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ting-Fang Che
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
| | - Syer Choon Lim
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
| | - Jocelyn Wang
- The College, The University of Chicago, Chicago, IL 60637, USA
| | - Wen-Sy Tsai
- Division of Colon and Rectal Surgery, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
- Graduate Institute of Clinical Medical Science, Chang Gung University, Linkou, Taoyuan, Taiwan
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Chun-Jen Huang
- Department of Chemical & Materials Engineering, and NCU-Covestro Research Center, National Central University, Jhong-Li, Taoyuan 320, Taiwan.
- R&D Center for Membrane Technology, Chung Yuan Christian University, 200 Chung Pei Rd., Chung-Li City 32023, Taiwan
| | - Ying-Chih Chang
- Genomics Research Center, Academia Sinica, 128, Sec 2, Academic Rd., Nankang, Taipei 115, Taiwan.
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
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2
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Chen D, Ni C, Yang C, Li Y, Wen X, Frank CW, Xie T, Ren H, Zhao Q. Orthogonal Photochemistry toward Direct Encryption of a 3D-Printed Hydrogel. Adv Mater 2023; 35:e2209956. [PMID: 36656747 DOI: 10.1002/adma.202209956] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Encryption technologies are essential for information security and product anti-counterfeiting, but they are typically restricted to planar surfaces. Encryption on complex 3D objects offers great potential to further improve security. However, it is rarely achieved owing to the lack of encoding strategies for nonplanar surfaces. Here, an approach is reported to directly encrypt on a 3D-printed object employing orthogonal photochemistry. In this system, visible light photochemistry is used for 3D printing of a hydrogel, and ultraviolet light is subsequently employed to activate its geometrically complex surface through the dissociation of ortho-nitrobenzyl ester units in a spatioselective manner for information coding. This approach offers a new way for more reliable encryption, and the underlying orthogonal photochemistry can be extended toward functional modification of 3D-printed products beyond information protection.
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Affiliation(s)
- Di Chen
- Ningbo Research Institute, Zhejiang University, Ningbo, 315100, China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Chujun Ni
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Chen Yang
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Ye Li
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xin Wen
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Tao Xie
- Ningbo Research Institute, Zhejiang University, Ningbo, 315100, China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Hua Ren
- Ningbo Research Institute, Zhejiang University, Ningbo, 315100, China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Qian Zhao
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
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3
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Chen JY, Chou HH, Lim SC, Huang YJ, Lai KC, Guo CL, Tung CY, Su CT, Wang J, Liu E, Han HF, Yeh PY, Hu CM, Dunn AR, Frank CW, Wu YC, Yang MH, Chang YC. Multiomic characterization and drug testing establish circulating tumor cells as an ex vivo tool for personalized medicine. iScience 2022; 25:105081. [PMID: 36204272 PMCID: PMC9529671 DOI: 10.1016/j.isci.2022.105081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/06/2022] [Accepted: 08/31/2022] [Indexed: 11/19/2022] Open
Abstract
Matching the treatment to an individual patient’s tumor state can increase therapeutic efficacy and reduce tumor recurrence. Circulating tumor cells (CTCs) derived from solid tumors are promising subjects for theragnostic analysis. To analyze how CTCs represent tumor states, we established cell lines from CTCs, primary and metastatic tumors from a mouse model and provided phenotypic and multiomic analyses of these cells. CTCs and metastatic cells, but not primary tumor cells, shared stochastic mutations and similar hypomethylation levels at transcription start sites. CTCs and metastatic tumor cells shared a hybrid epithelial/mesenchymal transcriptome state with reduced adhesive and enhanced mobilization characteristics. We tested anti-cancer drugs on tumor cells from a metastatic breast cancer patient. CTC responses mirrored the impact of drugs on metastatic rather than primary tumors. Our multiomic and clinical anti-cancer drug response results reveal that CTCs resemble metastatic tumors and establish CTCs as an ex vivo tool for personalized medicine. Primary, CTC and metastatic cell lines from mouse models were directly compared Multiomic and phenotypic data indicate circulating cells resemble metastatic cells CTCs and metastasis tumors from a patient similarly respond to anti-cancer drugs CTCs are thus potentially useful for screening individual patient drug responses
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Affiliation(s)
- Jia-Yang Chen
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115, Taiwan
| | - Hsu-Huan Chou
- Department of General Surgery, Chang-Gung Memorial Hospital, Linkou, Taoyuan 333, Taiwan
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
| | - Syer Choon Lim
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yen-Jang Huang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115, Taiwan
| | - Kuan-Chen Lai
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chin-Lin Guo
- Institute of Physics, Academia Sinica, Taipei 115, Taiwan
| | - Chien-Yi Tung
- Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | | | - Jocelyn Wang
- The College, The University of Chicago, Chicago, IL 60637, USA
| | - Edward Liu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Hsiao-Fen Han
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan
| | - Po-Ying Yeh
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Chun-Mei Hu
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Alexander R. Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Yi-Chun Wu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan
- Center for Computational and Systems Biology, National Taiwan University, Taipei 106, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
- Corresponding author
| | - Muh-Hwa Yang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei 112, Taiwan
- Corresponding author
| | - Ying-Chih Chang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115, Taiwan
- Biomedical Translational Research Center, Academia Sinica, Taipei 115, Taiwan
- Precision Health and Integrated Diagnostics Center, Stanford University, Stanford, CA 94305, USA
- Corresponding author
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Ciftcioglu GA, Frank CW. Influence of Mixed Imide Composition and Thermal Annealing on Ionic Liquid Uptake and Conductivity of Polyimide-Poly(ethylene glycol) Segmented Block Copolymer Membranes. Molecules 2021; 26:7450. [PMID: 34946531 PMCID: PMC8705581 DOI: 10.3390/molecules26247450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 11/29/2022] Open
Abstract
Understanding the impact of different bridging groups in the two-step polymerization of poly(ethylene glycol) (PEG)-incorporated polyimide (PI) materials is significant. It is known that the proton exchange membranes (PEMs) used in industry today can experience performance degradation under rising temperature conditions. Many efforts have been devoted to overcoming this problem by improving the physical and mechanical properties that extend the hygrothermal life of a PEM. This work examines the effect of oxygenated and fluorinated bridging anhydrides in the production of PI-PEG PEMs. It is shown that the dianhydride identity and the amount incorporated in the synthesis influences the properties of the segmented block copolymer (SBC) membranes, such as increased ionic liquid uptake (ILU), enhanced conductivity and higher Young's modulus favoring stiffness comparable to Nafion 115, an industrial standard. Investigations on the ionic conductivity of PI-PEG membranes were carried out to determine how thermal annealing would affect the material's performance as an ion-exchange membrane. By applying a thermal annealing process at 60 °C for one hour, the conductivities of synthesized segmented block copolymer membranes values were increased. The effect of thermal annealing on the mechanical properties was also shown for the undoped SBC via measuring the change in the Young's modulus. These higher ILU abilities and mechanical behavior changes are thought to arise from the interaction between PEG molecules and ethylammonium nitrate (EAN) ionic liquid (IL). In addition, higher interconnected routes provide a better ion-transfer environment within the membrane. It was found that the conductivity was increased by a factor of ten for undoped and a factor of two to seven for IL-doped membranes after thermal annealing.
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Affiliation(s)
- Gokcen A. Ciftcioglu
- Department of Chemical Engineering, Marmara University, Istanbul 34722, Turkey
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
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5
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Lee S, Jeong W, Frank CW, Yoon DY. Surface Characteristics of Poly(alkyl methacrylate)s from Molecular Dynamics Simulations Using All-Atom Force Field. Macromol Rapid Commun 2021; 43:e2100614. [PMID: 34873776 DOI: 10.1002/marc.202100614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/23/2021] [Indexed: 11/10/2022]
Abstract
Molecular dynamics (MD) simulations of melt films of poly(alkyl methacrylate)s (PAMAs) with methyl, ethyl, and n-butyl substituents, respectively, have been performed using an all-atom model to investigate their surface and thin film properties. The applied all-atom force fields predict the bulk densities of PAMAs in good agreement with experiments. Moreover, predictions of the surface tensions of PMMA, PEMA, and Pn-BMA melts are in reasonably good agreement with experiments. The density profiles and orientational-order parameters of chain segments show atomic-scale characteristics in the air/polymer interfacial region. In the surface region, the backbone segments of PAMAs form a well-defined layer structure with the chain vectors oriented parallel to the surface, while the ester side-chains strongly segregate to the surface region and show perpendicular orientation to the surface, with the most pronounced surface segregation noted for Pn-BMA. Such surface segregations of chain segments make it difficult to apply a simple relationship between the cohesive energy density and the surface tension of polymers, for example, and should be taken into account in relating the surface/thin film characteristics to the bulk properties of polymers in general.
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Affiliation(s)
- Sanghun Lee
- Department of Chemistry, Gachon University, Seongnam, Gyunggido, 13120, Korea
| | - Wonhee Jeong
- Cell Development Department, LG Energy Solution, Daejon, 34122, Korea
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Do Y Yoon
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
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6
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Ciftcioglu GA, Frank CW. Effect of Increased Ionic Liquid Uptake via Thermal Annealing on Mechanical Properties of Polyimide-Poly(ethylene glycol) Segmented Block Copolymer Membranes. Molecules 2021; 26:2143. [PMID: 33917907 PMCID: PMC8068311 DOI: 10.3390/molecules26082143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/06/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Proton exchange membranes (PEMs) suffer performance degradation under certain conditions-temperatures greater than 80 °C, relative humidity less than 50%, and water retention less than 22%. Novel materials are needed that have improved water retention, stability at higher temperatures, flexibility, conductivity, and the ability to function at low humidity. This work focuses on polyimide-poly(ethylene glycol) (PI-PEG) segmented block copolymer (SBC) membranes with high conductivity and mechanical strength. Membranes were prepared with one of two ionic liquids (ILs), either ethylammonium nitrate (EAN) or propylammonium nitrate (PAN), incorporated within the membrane structure to enhance the proton exchange capability. Ionic liquid uptake capacities were compared for two different temperatures, 25 and 60 °C. Then, conductivities were measured for a series of combinations of undoped or doped unannealed and undoped or doped annealed membranes. Stress and strain tests were performed for unannealed and thermally annealed undoped membranes. Later, these experiments were repeated for doped unannealed and thermally annealed. Mechanical and conductivity data were interpreted in the context of prior small angle X-ray scattering (SAXS) studies on similar materials. We have shown that varying the compositions of polyimide-poly(ethylene glycol) (PI-PEG) SBCs allowed the morphology in the system to be tuned. Since polyimides (PI) are made from the condensation of dianhydrides and diamines, this was accomplished using components having different functional groups. Dianhydrides having either fluorinated or oxygenated functional groups and diamines having either fluorinated or oxygenated diamines were used as well as mixtures of these species. Changing the morphology by creating macrophase separation elevated the IL uptake capacities, and in turn, increased their conductivities by a factor of three or more compared to Nafion 115. The stiffness of the membranes synthesized in this work was comparable to Nafion 115 and, thus, sufficient for practical applications.
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Affiliation(s)
- Gokcen A. Ciftcioglu
- Department of Chemical Engineering, Marmara University, Istanbul 34722, Turkey
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
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Kao KC, Yang AC, Huang W, Zhou C, Goodman ED, Holm A, Frank CW, Cargnello M. A General Approach for Monolayer Adsorption of High Weight Loadings of Uniform Nanocrystals on Oxide Supports. Angew Chem Int Ed Engl 2021; 60:7971-7979. [PMID: 33403788 DOI: 10.1002/anie.202017238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Indexed: 11/07/2022]
Abstract
Monodispersed metal and semiconductor nanocrystals have attracted great attention in fundamental and applied research due to their tunable size, morphology, and well-defined chemical composition. Utilizing these nanocrystals in a controllable way is highly desirable especially when using them as building blocks for the preparation of nanostructured materials. Their deposition onto oxide materials provide them with wide applicability in many areas, including catalysis. However, so far deposition methods are limited and do not provide control to achieve high particle loadings. This study demonstrates a general approach for the deposition of hydrophobic ligand-stabilized nanocrystals on hydrophilic oxide supports without ligand-exchange. Surface functionalization of the supports with primary amine groups either using an organosilane ((3-aminopropyl)trimethoxysilane) or bonding with aminoalcohols (3-amino-1,2-propanediol) were found to significantly improve the interaction between nanocrystals and supports achieving high loadings (>10 wt. %). The bonding method with aminoalcohols guarantees the opportunity to remove the binding molecules thus allowing clean metal/oxide materials to be obtained, which is of great importance in the preparation of supported nanocrystals for heterogeneous catalysis.
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Affiliation(s)
- Kun-Che Kao
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - An-Chih Yang
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Weixin Huang
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Chengshuang Zhou
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Emmett D Goodman
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Alexander Holm
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
| | - Matteo Cargnello
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94304, USA
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8
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Kao K, Yang A, Huang W, Zhou C, Goodman ED, Holm A, Frank CW, Cargnello M. A General Approach for Monolayer Adsorption of High Weight Loadings of Uniform Nanocrystals on Oxide Supports. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kun‐Che Kao
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - An‐Chih Yang
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Weixin Huang
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Chengshuang Zhou
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Emmett D. Goodman
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Alexander Holm
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Curtis W. Frank
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
| | - Matteo Cargnello
- Department of Chemical Engineering Stanford University Stanford CA 94304 USA
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9
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Holm A, Goodman ED, Stenlid JH, Aitbekova A, Zelaya R, Diroll BT, Johnston-Peck AC, Kao KC, Frank CW, Pettersson LGM, Cargnello M. Nanoscale Spatial Distribution of Supported Nanoparticles Controls Activity and Stability in Powder Catalysts for CO Oxidation and Photocatalytic H 2 Evolution. J Am Chem Soc 2020; 142:14481-14494. [PMID: 32786792 PMCID: PMC7924732 DOI: 10.1021/jacs.0c03842] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Supported metal nanoparticles are essential components of high-performing catalysts, and their structures are intensely researched. In comparison, nanoparticle spatial distribution in powder catalysts is conventionally not quantified, and the influence of this collective property on catalyst performance remains poorly investigated. Here, we demonstrate a general colloidal self-assembly method to control uniformity of nanoparticle spatial distribution on common industrial powder supports. We quantify distributions on the nanoscale using image statistics and show that the type of nanospatial distribution determines not only the stability, but also the activity of heterogeneous catalysts. Widely investigated systems (Au-TiO2 for CO oxidation thermocatalysis and Pd-TiO2 for H2 evolution photocatalysis) were used to showcase the universal importance of nanoparticle spatial organization. Spatially and temporally resolved microkinetic modeling revealed that nonuniformly distributed Au nanoparticles suffer from local depletion of surface oxygen, and therefore lower CO oxidation activity, as compared to uniformly distributed nanoparticles. Nanoparticle spatial distribution also determines the stability of Pd-TiO2 photocatalysts, because nonuniformly distributed nanoparticles sinter while uniformly distributed nanoparticles do not. This work introduces new tools to evaluate and understand catalyst collective (ensemble) properties in powder catalysts, which thereby pave the way to more active and stable heterogeneous catalysts.
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Affiliation(s)
- Alexander Holm
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Emmett D. Goodman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Joakim Halldin Stenlid
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aisulu Aitbekova
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Rosadriana Zelaya
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Benjamin T. Diroll
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | - Aaron C. Johnston-Peck
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Kun-Che Kao
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Lars G. M. Pettersson
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA 94305, USA
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10
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Lee S, Frank CW, Yoon DY. Interface Characteristics of Neat Melts and Binary Mixtures of Polyethylenes from Atomistic Molecular Dynamics Simulations. Polymers (Basel) 2020; 12:polym12051059. [PMID: 32384644 PMCID: PMC7284576 DOI: 10.3390/polym12051059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/22/2022] Open
Abstract
Molecular dynamics simulations of free-standing thin films of neat melts of polyethylene (PE) chains up to C150H302 and their binary mixtures with n-C13H28 are performed employing a united atom model. We estimate the surface tension values of PE melts from the atomic virial tensor over a range of temperatures, which are in good agreement with experimental results. Compared with short n-alkane systems, there is an enhanced surface segregation of methyl chain ends in longer PE chains. Moreover, the methyl groups become more segregated in the surface region with decreasing temperature, leading to the conclusion that the surface-segregation of methyl chain ends mainly arises from the enthalpic origin attributed to the lower cohesive energy density of terminal methyl groups. In the mixtures of two different chain lengths, the shorter chains are more likely to be found in the surface region, and this molecular segregation in moderately asymmetric mixtures in the chain length (C13H28 + C44H90) is dominated by the enthalpic effect of methyl chain ends. Such molecular segregation is further enhanced and dominated by the entropic effect of conformational constraints in the surface for the highly asymmetric mixtures containing long polymer chains (C13H28 + C150H3020). The estimated surface tension values of the mixtures are consistent with the observed molecular segregation characteristics. Despite this molecular segregation, the normalized density of methyl chain ends of the longer chain is more strongly enhanced, as compared with the all-segment density of the longer chain itself, in the surface region of melt mixtures. In addition, the molecular segregation results in higher order parameter of the shorter-chain segments at the surface and deeper persistence of surface-induced segmental order into the film for the longer chains, as compared with those in neat melt films.
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Affiliation(s)
- Sanghun Lee
- Department of Chemistry, Gachon University, Seongnam 13120, Gyunggido, Korea;
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
| | - Do Y. Yoon
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA;
- Correspondence:
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11
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Adatia KK, Holm A, Southan A, Frank CW, Tovar GEM. Structure–property relations of amphiphilic poly(furfuryl glycidyl ether)- block-poly(ethylene glycol) macromonomers at the air–water interface. Polym Chem 2020. [DOI: 10.1039/d0py00697a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Structure–property relations of poly(furfuryl glycidyl ether)-block-poly(ethylene glycol) macromonomers at the air–water interface are studied with a Langmuir film balance.
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Affiliation(s)
- Karishma K. Adatia
- Institute of Interfacial Process Engineering and Plasma Technology IGVP
- University of Stuttgart
- D-70569 Stuttgart
- Germany
- Department of Chemical Engineering
| | - Alexander Holm
- Department of Chemical Engineering
- Stanford University
- Stanford
- USA
| | - Alexander Southan
- Institute of Interfacial Process Engineering and Plasma Technology IGVP
- University of Stuttgart
- D-70569 Stuttgart
- Germany
| | - Curtis W. Frank
- Department of Chemical Engineering
- Stanford University
- Stanford
- USA
| | - Günter E. M. Tovar
- Institute of Interfacial Process Engineering and Plasma Technology IGVP
- University of Stuttgart
- D-70569 Stuttgart
- Germany
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB
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12
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Woo E, Coletta E, Holm A, Mun J, Toney MF, Yoon DY, Frank CW. Polyimide‐PEG Segmented Block Copolymer Membranes with High Proton Conductivity by Improving Bicontinuous Nanostructure of Ionic Liquid‐Doped Films. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201900006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Euntaek Woo
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
- Lotte Advanced Materials Co., Ltd. Uiwang‐si Gyeonggi‐do 437–711 Republic of Korea
| | - Elyse Coletta
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
| | - Alexander Holm
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
| | - Jaewan Mun
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
| | - Michael F. Toney
- SLAC National Accelerator Laboratory Synchrotron Radiation Light Source Menlo Park CA 94205 USA
| | - Do Y. Yoon
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
| | - Curtis W. Frank
- Department of Chemical Engineering Stanford University Stanford CA 94305 USA
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13
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Holm A, Kunz L, Riscoe AR, Kao KC, Cargnello M, Frank CW. General Self-Assembly Method for Deposition of Graphene Oxide into Uniform Close-Packed Monolayer Films. Langmuir 2019; 35:4460-4470. [PMID: 30836748 DOI: 10.1021/acs.langmuir.8b03994] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Depositing a morphologically uniform monolayer film of graphene oxide (GO) single-layer sheets is an important step in the processing of many composites and devices. Conventional Langmuir-Blodgett (LB) deposition is often considered to give the highest degree of morphology control, but film microstructures still vary widely between GO samples. The main challenge is in the sensitive self-assembly of GO samples with different sheet sizes and degrees of oxidation. To overcome this drawback, here, we identify a general method that relies on robust assembly between GO and a cationic surfactant (cationic surfactant-assisted LB). We systematically compared conventional LB and cationic surfactant-assisted LB for three common GO samples of widely different sheet sizes and degrees of oxidation. Although conventional LB may occasionally provide satisfactory film morphology, cationic surfactant-assisted LB is general and allows deposition of films with tunable and uniform morphologies-ranging from close-packed to overlapping single layers-from all three types of GO samples investigated. Because cationic surfactant-assisted LB is robust and general, we expect this method to broaden and facilitate the use of GO in many applications where precise control over film morphology is crucial.
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14
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Holm A, Wrasman CJ, Kao KC, Riscoe AR, Cargnello M, Frank CW. Langmuir-Blodgett Deposition of Graphene Oxide-Identifying Marangoni Flow as a Process that Fundamentally Limits Deposition Control. Langmuir 2018; 34:9683-9691. [PMID: 30025460 DOI: 10.1021/acs.langmuir.8b00777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Langmuir-Blodgett deposition is a popular route to produce thin films of graphene oxide for applications such as transparent conductors and biosensors. Unfortunately, film morphologies vary from sample to sample, often with undesirable characteristics such as folded sheets and patchwise depositions. In conventional Langmuir-Blodgett deposition of graphene oxide, alcohol (typically methanol) is used to spread the graphene oxide sheets onto an air-water interface before deposition onto substrates. Here we show that methanol gives rise to Marangoni flow, which fundamentally limits control over Langmuir-Blodgett depositions of graphene oxide. We directly identified the presence of Marangoni flow by using photography, and we evaluated depositions with atomic force microscopy and scanning electron microscopy. The disruptive effect of Marangoni flow was demonstrated by comparing conventional Langmuir-Blodgett depositions to depositions where Marangoni flow was suppressed by a surfactant. Because methanol is the standard spreading solvent for conventional Langmuir-Blodgett deposition of graphene oxide, Marangoni flow is a general problem and may partly explain the wide variety of undesirable film morphologies reported in the literature.
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Affiliation(s)
- Alexander Holm
- Department of Chemical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Cody J Wrasman
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis , Stanford University , Stanford , California 94305 , United States
| | - Kun-Che Kao
- Department of Chemical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Andrew R Riscoe
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis , Stanford University , Stanford , California 94305 , United States
| | - Matteo Cargnello
- Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis , Stanford University , Stanford , California 94305 , United States
| | - Curtis W Frank
- Department of Chemical Engineering , Stanford University , Stanford , California 94305 , United States
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15
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Ng SS, Saeb-Parsy K, Blackford SJI, Segal JM, Serra MP, Horcas-Lopez M, No DY, Mastoridis S, Jassem W, Frank CW, Cho NJ, Nakauchi H, Glenn JS, Rashid ST. Human iPS derived progenitors bioengineered into liver organoids using an inverted colloidal crystal poly (ethylene glycol) scaffold. Biomaterials 2018; 182:299-311. [PMID: 30149262 PMCID: PMC6131727 DOI: 10.1016/j.biomaterials.2018.07.043] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 07/25/2018] [Indexed: 12/29/2022]
Abstract
Generation of human organoids from induced pluripotent stem cells (iPSCs) offers exciting possibilities for developmental biology, disease modelling and cell therapy. Significant advances towards those goals have been hampered by dependence on animal derived matrices (e.g. Matrigel), immortalized cell lines and resultant structures that are difficult to control or scale. To address these challenges, we aimed to develop a fully defined liver organoid platform using inverted colloid crystal (ICC) whose 3-dimensional mechanical properties could be engineered to recapitulate the extracellular niche sensed by hepatic progenitors during human development. iPSC derived hepatic progenitors (IH) formed organoids most optimally in ICC scaffolds constructed with 140 μm diameter pores coated with type I collagen in a two-step process mimicking liver bud formation. The resultant organoids were closer to adult tissue, compared to 2D and 3D controls, with respect to morphology, gene expression, protein secretion, drug metabolism and viral infection and could integrate, vascularise and function following implantation into livers of immune-deficient mice. Preliminary interrogation of the underpinning mechanisms highlighted the importance of TGFβ and hedgehog signalling pathways. The combination of functional relevance with tuneable mechanical properties leads us to propose this bioengineered platform to be ideally suited for a range of future mechanistic and clinical organoid related applications.
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Affiliation(s)
- Soon Seng Ng
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK; Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kourosh Saeb-Parsy
- Department of Surgery, University of Cambridge and the Cambridge NIHR Biomedical Research Centre, Cambridge, UK
| | - Samuel J I Blackford
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Joe M Segal
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Maria Paola Serra
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Marta Horcas-Lopez
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Da Yoon No
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA; Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Sotiris Mastoridis
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Wayel Jassem
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Nam Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Hiromitsu Nakauchi
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Jeffrey S Glenn
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
| | - S Tamir Rashid
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, England, UK; Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA.
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16
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Ng SS, Xiong A, Nguyen K, Masek M, No DY, Elazar M, Shteyer E, Winters MA, Voedisch A, Shaw K, Rashid ST, Frank CW, Cho NJ, Glenn JS. Long-term culture of human liver tissue with advanced hepatic functions. JCI Insight 2017; 2:90853. [PMID: 28570275 DOI: 10.1172/jci.insight.90853] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 04/27/2017] [Indexed: 01/16/2023] Open
Abstract
A major challenge for studying authentic liver cell function and cell replacement therapies is that primary human hepatocytes rapidly lose their advanced function in conventional, 2-dimensional culture platforms. Here, we describe the fabrication of 3-dimensional hexagonally arrayed lobular human liver tissues inspired by the liver's natural architecture. The engineered liver tissues exhibit key features of advanced differentiation, such as human-specific cytochrome P450-mediated drug metabolism and the ability to support efficient infection with patient-derived inoculums of hepatitis C virus. The tissues permit the assessment of antiviral agents and maintain their advanced functions for over 5 months in culture. This extended functionality enabled the prediction of a fatal human-specific hepatotoxicity caused by fialuridine (FIAU), which had escaped detection by preclinical models and short-term clinical studies. The results obtained with the engineered human liver tissue in this study provide proof-of-concept determination of human-specific drug metabolism, demonstrate the ability to support infection with human hepatitis virus derived from an infected patient and subsequent antiviral drug testing against said infection, and facilitate detection of human-specific drug hepatotoxicity associated with late-onset liver failure. Looking forward, the scalability and biocompatibility of the scaffold are also ideal for future cell replacement therapeutic strategies.
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Affiliation(s)
- Soon Seng Ng
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.,School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Anming Xiong
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Khanh Nguyen
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Marilyn Masek
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.,Department of Pathology, Stanford University School of Medicine
| | - Da Yoon No
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford California, USA
| | - Menashe Elazar
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Eyal Shteyer
- Department of Pediatric Gastroenterology and Nutrition, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Mark A Winters
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | | | - Kate Shaw
- Department of Obstetrics and Gynecology
| | - Sheikh Tamir Rashid
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stanford California, USA
| | - Nam Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jeffrey S Glenn
- Division of Gastroenterology and Hepatology, Department of Medicine.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
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17
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Lyulin AV, Balabaev NK, Baljon ARC, Mendoza G, Frank CW, Yoon DY. Interfacial and topological effects on the glass transition in free-standing polystyrene films. J Chem Phys 2017; 146:203314. [DOI: 10.1063/1.4977042] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Lee S, Lyulin AV, Frank CW, Yoon DY. Interface characteristics of polystyrene melts in free-standing thin films and on graphite surface from molecular dynamics simulations. POLYMER 2017. [DOI: 10.1016/j.polymer.2017.02.078] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Engberg K, Waters DJ, Kelmanovich S, Parke-Houben R, Hartmann L, Toney MF, Frank CW. Self-assembly of cholesterol tethered within hydrogel networks. POLYMER 2016. [DOI: 10.1016/j.polymer.2016.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Fox CH, ter Hurrne GM, Wojtecki RJ, Jones GO, Horn HW, Meijer EW, Frank CW, Hedrick JL, García JM. Supramolecular motifs in dynamic covalent PEG-hemiaminal organogels. Nat Commun 2015; 6:7417. [PMID: 26174864 PMCID: PMC4518264 DOI: 10.1038/ncomms8417] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/06/2015] [Indexed: 12/28/2022] Open
Abstract
Dynamic covalent materials are stable materials that possess reversible behaviour triggered by stimuli such as light, redox conditions or temperature; whereas supramolecular crosslinks depend on the equilibrium constant and relative concentrations of crosslinks as a function of temperature. The combination of these two reversible chemistries can allow access to materials with unique properties. Here, we show that this combination of dynamic covalent and supramolecular chemistry can be used to prepare organogels comprising distinct networks. Two materials containing hemiaminal crosslink junctions were synthesized; one material is comprised of dynamic covalent junctions and the other contains hydrogen-bonding bis-hemiaminal moieties. Under specific network synthesis conditions, these materials exhibited self-healing behaviour. This work reports on both the molecular-level detail of hemiaminal crosslink junction formation as well as the macroscopic behaviour of hemiaminal dynamic covalent network (HDCN) elastomeric organogels. These materials have potential applications as elastomeric components in printable materials, cargo carriers and adhesives.
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Affiliation(s)
- Courtney H. Fox
- Department of Chemical Engineering, Stanford University, 443 via Ortega, Stanford, California 94305, USA
| | - Gijs M. ter Hurrne
- Eindhoven University of Technology, Post Office Box 513, Eindhoven 5600 MB, The Netherlands
| | - Rudy J. Wojtecki
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - Gavin O. Jones
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - Hans W. Horn
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - E. W. Meijer
- Eindhoven University of Technology, Post Office Box 513, Eindhoven 5600 MB, The Netherlands
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, 443 via Ortega, Stanford, California 94305, USA
| | - James L. Hedrick
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - Jeannette M. García
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
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21
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Fox CH, Engler AC, Toney MF, Hedrick JL, Frank CW. Tunable mesoscale-structured self-assembled hydrogels synthesized by organocatalytic ring-opening polymerization. POLYMER 2015. [DOI: 10.1016/j.polymer.2015.03.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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22
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He SS, Strickler AL, Frank CW. A semi-interpenetrating network approach for dimensionally stabilizing highly-charged anion exchange membranes for alkaline fuel cells. ChemSusChem 2015; 8:1472-1483. [PMID: 25820199 DOI: 10.1002/cssc.201500133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 06/04/2023]
Abstract
There is a delicate balance between ion exchange capacity (IEC), conductivity, and dimensional stability in anion exchange membranes as higher charge content can lead to increased water uptake, causing excessive swelling and charge dilution. Using highly-charged benzyltrimethylammonium polysulfone (IEC=2.99 mEq g(-1) ) as a benchmark (which ruptured in water even at room temperature), we report the ability to dramatically decrease water uptake using a semi-interpenetrating network wherein we reinforced the linear polyelectrolyte with a crosslinked poly(styrene-co-divinylbenzene) network. These membranes show enhanced dimensional stability as a result of lower water uptake (75 % vs. 301 % at 25 °C) while maintaining excellent hydroxide conductivity (up to 50 mS cm(-1) at 25 °C). These improvements produced an enhanced alkaline fuel cell capable of generating 236 mW cm(-2) peak power density at 80 °C. This method is easily adaptable and can be a viable strategy for stabilizing existing systems.
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Affiliation(s)
- Steve S He
- Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305 (USA). ,
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23
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Zheng LL, Vanchinathan V, Dalal R, Noolandi J, Waters DJ, Hartmann L, Cochran JR, Frank CW, Yu CQ, Ta CN. Biocompatibility of poly(ethylene glycol) and poly(acrylic acid) interpenetrating network hydrogel by intrastromal implantation in rabbit cornea. J Biomed Mater Res A 2015; 103:3157-65. [PMID: 25778285 DOI: 10.1002/jbm.a.35453] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/24/2015] [Accepted: 03/09/2015] [Indexed: 11/08/2022]
Abstract
We evaluated the biocompatibility of a poly(ethylene glycol) and poly(acrylic acid) (PEG/PAA) interpenetrating network hydrogel designed for artificial cornea in a rabbit model. PEG/PAA hydrogel measuring 6 mm in diameter was implanted in the corneal stroma of twelve rabbits. Stromal flaps were created with a microkeratome. Randomly, six rabbits were assigned to bear the implant for 2 months, two rabbits for 6 months, two rabbits for 9 months, one rabbit for 12 months, and one rabbit for 16 months. Rabbits were evaluated monthly. After the assigned period, eyes were enucleated, and corneas were processed for histology and immunohistochemistry. There were clear corneas in three of six rabbits that had implantation of hydrogel for 2 months. In the six rabbits with implant for 6 months or longer, the corneas remained clear in four. There was a high rate of epithelial defect and corneal thinning in these six rabbits. One planned 9-month rabbit developed extrusion of implant at 4 months. The cornea remained clear in the 16-month rabbit but histology revealed epithelial in-growth. Intrastromal implantation of PEG/PAA resulted in a high rate of long-term complications.
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Affiliation(s)
- Luo Luo Zheng
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California.,Department of Bioengineering, Stanford University School of Engineering, Stanford, California
| | - Vijay Vanchinathan
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Roopa Dalal
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Jaan Noolandi
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Dale J Waters
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Laura Hartmann
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Jennifer R Cochran
- Department of Bioengineering, Stanford University School of Engineering, Stanford, California
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University School of Engineering, Stanford, California
| | - Charles Q Yu
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
| | - Christopher N Ta
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Stanford, California
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24
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Cho NJ, Lee C, Pang PS, Pham EA, Fram B, Nguyen K, Xiong A, Sklan EH, Elazar M, Koytak ES, Kersten C, Kanazawa KK, Frank CW, Glenn JS. Phosphatidylinositol 4,5-bisphosphate is an HCV NS5A ligand and mediates replication of the viral genome. Gastroenterology 2015; 148:616-25. [PMID: 25479136 PMCID: PMC4339471 DOI: 10.1053/j.gastro.2014.11.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 11/21/2014] [Accepted: 11/23/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND & AIMS Phosphoinositides (PIs) bind and regulate localization of proteins via a variety of structural motifs. PI 4,5-bisphosphate (PI[4,5]P2) interacts with and modulates the function of several proteins involved in intracellular vesicular membrane trafficking. We investigated interactions between PI(4,5)P2 and hepatitis C virus (HCV) nonstructural protein 5A (NS5A) and effects on the viral life cycle. METHODS We used a combination of quartz crystal microbalance, circular dichroism, molecular genetics, and immunofluorescence to study specific binding of PI(4,5)P2 by the HCV NS5A protein. We evaluated the effects of PI(4,5)P2 on the function of NS5A by expressing wild-type or mutant forms of Bart79I or FL-J6/JFH-5'C19Rluc2AUbi21 RNA in Huh7 cells. We also studied the effects of strategies designed to inhibit PI(4,5)P2 on HCV replication in these cells. RESULTS The N-terminal amphipathic helix of NS5A bound specifically to PI(4,5)P2, inducing a conformational change that stabilized the interaction between NS5A and TBC1D20, which is required for HCV replication. A pair of positively charged residues within the amphipathic helix (the basic amino acid PI(4,5)P2 pincer domain) was required for PI(4,5)P2 binding and replication of the HCV-RNA genome. A similar motif was found to be conserved across all HCV isolates, as well as amphipathic helices of many pathogens and apolipoproteins. CONCLUSIONS PI(4,5)P2 binds to HCV NS5A to promote replication of the viral RNA genome in hepatocytes. Strategies to disrupt this interaction might be developed to inhibit replication of HCV and other viruses.
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Affiliation(s)
- Nam-Joon Cho
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Choongho Lee
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | - Phillip S. Pang
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Medicine, Division of Infectious Diseases, Stanford University School of Medicine
| | - Edward A. Pham
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Benjamin Fram
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Khanh Nguyen
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Anming Xiong
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Ella H. Sklan
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | - Menashe Elazar
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine
| | - Elif S. Koytak
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | - Caroline Kersten
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine
| | | | | | - Jeffrey S. Glenn
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine,Department of Microbiology and Immunology, Stanford University School of Medicine,Veterans Administration Medical Center, Palo Alto, California, United States of America,To whom correspondence should be addressed: Dr. Jeffrey S. Glenn, Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford University, CCSR 3115A, 269 Campus Drive, Stanford, CA, 94305-5171; Tel:(650) 725-3373; Fax:(650) 723-3032;
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25
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Bigdeli S, Dettloff RO, Frank CW, Davis RW, Crosby LD. A simple method for encapsulating single cells in alginate microspheres allows for direct PCR and whole genome amplification. PLoS One 2015; 10:e0117738. [PMID: 25689864 PMCID: PMC4331554 DOI: 10.1371/journal.pone.0117738] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 01/02/2015] [Indexed: 12/19/2022] Open
Abstract
Microdroplets are an effective platform for segregating individual cells and amplifying DNA. However, a key challenge is to recover the contents of individual droplets for downstream analysis. This paper offers a method for embedding cells in alginate microspheres and performing multiple serial operations on the isolated cells. Rhodobacter sphaeroides cells were diluted in alginate polymer and sprayed into microdroplets using a fingertip aerosol sprayer. The encapsulated cells were lysed and subjected either to conventional PCR, or whole genome amplification using either multiple displacement amplification (MDA) or a two-step PCR protocol. Microscopic examination after PCR showed that the lumen of the occupied microspheres contained fluorescently stained DNA product, but multiple displacement amplification with phi29 produced only a small number of polymerase colonies. The 2-step WGA protocol was successful in generating fluorescent material, and quantitative PCR from DNA extracted from aliquots of microspheres suggested that the copy number inside the microspheres was amplified up to 3 orders of magnitude. Microspheres containing fluorescent material were sorted by a dilution series and screened with a fluorescent plate reader to identify single microspheres. The DNA was extracted from individual isolates, re-amplified with full-length sequencing adapters, and then a single isolate was sequenced using the Illumina MiSeq platform. After filtering the reads, the only sequences that collectively matched a genome in the NCBI nucleotide database belonged to R. sphaeroides. This demonstrated that sequencing-ready DNA could be generated from the contents of a single microsphere without culturing. However, the 2-step WGA strategy showed limitations in terms of low genome coverage and an uneven frequency distribution of reads across the genome. This paper offers a simple method for embedding cells in alginate microspheres and performing PCR on isolated cells in common bulk reactions, although further work must be done to improve the amplification coverage of single genomes.
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Affiliation(s)
- Saharnaz Bigdeli
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, 3165 Porter Drive, Palo Alto, CA 94304, United States of America
- Department of Chemical Engineering, Stanford University, Stanford, CA, United States of America
| | - Roger O. Dettloff
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, 3165 Porter Drive, Palo Alto, CA 94304, United States of America
- Caerus Molecular Diagnostics, Mountain View, CA, United States of America
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA, United States of America
| | - Ronald W. Davis
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, 3165 Porter Drive, Palo Alto, CA 94304, United States of America
| | - Laurel D. Crosby
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, 3165 Porter Drive, Palo Alto, CA 94304, United States of America
- * E-mail:
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26
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Parke-Houben R, Fox CH, Zheng LL, Waters DJ, Cochran JR, Ta CN, Frank CW. Interpenetrating polymer network hydrogel scaffolds for artificial cornea periphery. J Mater Sci Mater Med 2015; 26:107. [PMID: 25665845 DOI: 10.1007/s10856-015-5442-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 12/14/2014] [Indexed: 06/04/2023]
Abstract
Three-dimensional scaffolds based on inverted colloidal crystals (ICCs) were fabricated from sequentially polymerized interpenetrating polymer network (IPN) hydrogels of poly(ethyleneglycol) and poly(acrylic acid). This high-strength, high-water-content IPN hydrogel may be suitable for use in an artificial cornea application. Development of a highly porous, biointegrable region at the periphery of the artificial cornea device is critical to long-term retention of the implant. The ICC fabrication technique produced scaffolds with well-controlled, tunable pore and channel dimensions. When surface functionalized with extracellular matrix proteins, corneal fibroblasts were successfully cultured on IPN hydrogel scaffolds, demonstrating the feasibility of these gels as materials for the artificial cornea porous periphery. Porous hydrogels with and without cells were visualized non-invasively in the hydrated state using variable-pressure scanning electron microscopy.
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Affiliation(s)
- Rachel Parke-Houben
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford, CA, 94305-5025, USA
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27
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Lee ALZ, Venkataraman S, Fox CH, Coady DJ, Frank CW, Hedrick JL, Yang YY. Modular composite hydrogels from cholesterol-functionalized polycarbonates for antimicrobial applications. J Mater Chem B 2015; 3:6953-6963. [DOI: 10.1039/c5tb00811e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A modular and versatile approach of mixing pre-optimized functional components with ABA-triblock gelators to access drug-loaded or antimicrobial gel is presented.
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Affiliation(s)
- Ashlynn L. Z. Lee
- Institute of Bioengineering and Nanotechnology
- Singapore 138669
- Singapore
| | | | - Courtney H. Fox
- Department of Chemical Engineering
- Stanford University
- Stanford
- USA
| | | | - Curtis W. Frank
- Department of Chemical Engineering
- Stanford University
- Stanford
- USA
| | | | - Yi Yan Yang
- Institute of Bioengineering and Nanotechnology
- Singapore 138669
- Singapore
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28
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Abstract
Surface-tethered chemoresponsive polypeptides prepared by surface-initiated vapor deposition polymerization were used to investigate conversion efficiency between α-helical and β-sheet conformations.
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Affiliation(s)
| | - Yuli Wang
- Department of Chemistry
- University of North Carolina
- Chapel Hill
- USA
| | - Curtis W. Frank
- Department of Chemical Engineering
- Stanford University
- Stanford
- USA
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29
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Coletta E, Toney MF, Frank CW. Influences of liquid electrolyte and polyimide identity on the structure and conductivity of polyimide-poly(ethylene glycol) materials. J Appl Polym Sci 2014. [DOI: 10.1002/app.41675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Elyse Coletta
- Department of Chemical Engineering; Stanford University; Stanford California 94305
| | - Michael F. Toney
- Stanford Synchrotron Radiation Lightsource; Menlo Park California 94025
| | - Curtis W. Frank
- Department of Chemical Engineering; Stanford University; Stanford California 94305
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30
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Tsui A, Frank CW. Comparison of anhydrous and monohydrated forms of orotic acid as crystal nucleating agents for poly(3-hydroxybutyrate-co-3-hydroxyvalerate). POLYMER 2014. [DOI: 10.1016/j.polymer.2014.09.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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31
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Tsui A, Wright Z, Frank CW. Prediction of gas solubility in poly(3-hydroxybutyrate- co
-3-hydroxyvalerate) melt to inform process design and resulting foam microstructure. POLYM ENG SCI 2014. [DOI: 10.1002/pen.23822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amy Tsui
- Department of Chemical Engineering; Stanford University; Stanford California 94305
| | - Zach Wright
- Department of Chemical Engineering; Stanford University; Stanford California 94305
| | - Curtis W. Frank
- Department of Chemical Engineering; Stanford University; Stanford California 94305
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32
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Affiliation(s)
- Amy Tsui
- Department
of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford, California 94305, United States
| | - Curtis W. Frank
- Department
of Chemical Engineering, Stanford University, 381 North-South Mall, Stanford, California 94305, United States
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Abstract
The temporospatial regulation of axon outgrowth is useful for guiding de novo connectivity or re-connectivity of neurons in neurological injury or disease. Here we report the successful construction of a biocompatible guidance device, in which a linear propagation of IGF-1 gradient sequentially directs axon outgrowth. We observe the extensive in vitro axonal extension over 5 mm with a desired growth rate of ∼ 1 mm/day.
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Affiliation(s)
- Wonjae Lee
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
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Jackman JA, Zhao Z, Zhdanov VP, Frank CW, Cho NJ. Vesicle adhesion and rupture on silicon oxide: influence of freeze-thaw pretreatment. Langmuir 2014; 30:2152-60. [PMID: 24512463 DOI: 10.1021/la404582n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We have investigated the effect of freeze-thaw (FT) pretreatment on the adhesion and rupture of extruded vesicles over a wide range of vesicle sizes. To characterize the size distributions of vesicles obtained with and without FT pretreatment, dynamic light scattering (DLS) experiments were performed. The interaction between extruded vesicles and a silicon oxide substrate was investigated by quartz crystal microbalance with dissipation (QCM-D) monitoring, with a focus on comparative analysis of similar-sized vesicles with and without FT pretreatment. Under this condition, there was a smaller mass load at the critical coverage associated with untreated vesicles, as compared to vesicles which had been subjected to FT pretreatment. In addition, the rupture of treated vesicles generally resulted in formation of a complete planar bilayer, while the adlayer was more heterogeneous when employing untreated vesicles. Combined with kinetic analysis and extended-DLVO model calculations, the experimental evidence suggests that the differences arising from FT pretreatment are due to characteristics of the vesicle size distribution and also multilamellarity of an appreciable fraction of untreated vesicles. Taken together, our findings clarify the influence of FT pretreatment on model membrane fabrication on solid supports.
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Affiliation(s)
- Joshua A Jackman
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, 639798 Singapore
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Abstract
The performance of medical implants and devices is dependent on the biocompatibility of the interfacial region between tissue and the implant material. Polymeric hydrogels are attractive materials for use as biocompatible surface coatings for metal implants. In such systems, a factor that is critically important for the longevity of an implant is the formation of a robust bond between the hydrogel layer and the implant metal surface and the ability for this assembly to withstand physiological conditions. Here, we describe the grafting of cross-linked hydrogel networks to titanium surfaces using grit-blasting and subsequent chemical functionalization using a silane-based adhesion promoter. Metal surface characterization was carried out using profilometry, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) analysis. Hydrogel layers composed of poly(ethylene glycol)-dimethacrylate (PEG-DMA), poly(2-hydroxyethylmethacrylate) (PHEMA), or poly(ethylene glycol)/poly(acrylic acid) (PEG/PAA) semi-interpenetrating polymer networks (semi-IPNs) have been prepared. The mechanical properties of these hydrogel-metal assemblies have been characterized using lap-shear measurements, and the surface morphology was studied by SEM and EDX. We have shown that both high surface roughness and chemical functionalization are critical for adhesion of the hydrogel layer to the titanium substrate.
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Affiliation(s)
- Beinn V O Muir
- Department of Chemical Engineering, Stanford University , 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
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36
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Wright ZC, Frank CW. Increasing cell homogeneity of semicrystalline, biodegradable polymer foams with a narrow processing window via rapid quenching. POLYM ENG SCI 2014. [DOI: 10.1002/pen.23847] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Zachary C. Wright
- Department of Chemical Engineering; Stanford University; Stanford California
| | - Curtis W. Frank
- Department of Chemical Engineering; Stanford University; Stanford California
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37
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Cho NJ, Hwang LY, Solandt JJR, Frank CW. Comparison of Extruded and Sonicated Vesicles for Planar Bilayer Self-Assembly. Materials (Basel) 2013; 6:3294-3308. [PMID: 28811437 PMCID: PMC5521307 DOI: 10.3390/ma6083294] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/22/2013] [Accepted: 07/24/2013] [Indexed: 01/27/2023]
Abstract
Lipid vesicles are an important class of biomaterials that have a wide range of applications, including drug delivery, cosmetic formulations and model membrane platforms on solid supports. Depending on the application, properties of a vesicle population such as size distribution, charge and permeability need to be optimized. Preparation methods such as mechanical extrusion and sonication play a key role in controlling these properties, and yet the effects of vesicle preparation method on vesicular properties and integrity (e.g., shape, size, distribution and tension) remain incompletely understood. In this study, we prepared vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid by either extrusion or sonication, and investigated the effects on vesicle size distribution over time as well as the concomitant effects on the self-assembly of solid-supported planar lipid bilayers. Dynamic light scattering (DLS), quartz crystal microbalance with dissipation (QCM-D) monitoring, fluorescence recovery after photobleaching (FRAP) and atomic force microscopy (AFM) experiments were performed to characterize vesicles in solution as well as their interactions with silicon oxide substrates. Collectively, the data support that sonicated vesicles offer more robust control over the self-assembly of homogenous planar lipid bilayers, whereas extruded vesicles are vulnerable to aging and must be used soon after preparation.
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Affiliation(s)
- Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
| | - Lisa Y Hwang
- Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, CA 94305, USA.
| | - Johan J R Solandt
- Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, CA 94305, USA.
| | - Curtis W Frank
- Department of Chemical Engineering, Stanford University, Stauffer III, 381 North-South Mall, Stanford, CA 94305, USA.
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38
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Farooqui N, Myung D, Koh W, Masek M, Dalal R, Carrasco MR, Noolandi J, Frank CW, Ta CN. Histological Processing of pH-Sensitive Hydrogels Used in Corneal Implant Applications. J Histotechnol 2013. [DOI: 10.1179/his.2007.30.3.157] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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39
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Abstract
Environmental concerns have led to the development of biorenewable polymers with the ambition to utilize them at an industrial scale. Poly(lactic acid) and poly(hydroxyalkanoates) are semicrystalline, biorenewable polymers that have been identified as the most promising alternatives to conventional plastics. However, both are inherently susceptible to brittleness and degradation during thermal processing; we discuss several approaches to overcome these problems to create a balance between durability and biodegradability. For example, copolymers and blends can increase ductility and the thermal-processing window. Furthermore, chain modifications (e.g., branching/crosslinking), processing techniques (fiber drawing/annealing), or additives (plasticizers/nucleating agents) can improve mechanical properties and prevent thermal degradation during processing. Finally, we examine the impacts of morphology on end-of-life degradation to complete the picture for the most common renewable polymers.
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Affiliation(s)
- Amy Tsui
- Department of Chemical Engineering, Stanford University, Stanford, California 94305;, ,
| | - Zachary C. Wright
- Department of Chemical Engineering, Stanford University, Stanford, California 94305;, ,
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, California 94305;, ,
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40
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Tan XW, Hartman L, Tan KP, Poh R, Myung D, Zheng LL, Waters D, Noolandi J, Beuerman RW, Frank CW, Ta CN, Tan DTH, Mehta JS. In vivo biocompatibility of two PEG/PAA interpenetrating polymer networks as corneal inlays following deep stromal pocket implantation. J Mater Sci Mater Med 2013; 24:967-977. [PMID: 23354737 PMCID: PMC3620449 DOI: 10.1007/s10856-012-4848-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/29/2012] [Indexed: 06/01/2023]
Abstract
This study compared the effects of implanting two interpenetrating polymer networks (IPNs) into rabbit corneas. The first (Implant 1) was based on PEG-diacrylate, the second (Implant 2) was based on PEG-diacrylamide. There were inserted into deep stromal pockets created using a manual surgical technique for either 3 or 6 months. The implanted corneas were compared with normal and sham-operated corneas through slit lamp observation, anterior segment optical coherence tomography, in vivo confocal scanning and histological examination. Corneas with Implant 1 (based on PEG-diacrylate) developed diffuse haze, ulcers and opacities within 3 months, while corneas with Implant 2 (based on PEG-diacrylamide) remained clear at 6 months. They also exhibited normal numbers of epithelial cell layers, without any immune cell infiltration, inflammation, oedema or neovascularisation at post-operative 6 month. Morphological studies showed transient epithelial layer thinning over the hydrogel inserted area and elevated keratocyte activity at 3 months; however, the epithelium thickness and keratocyte morphology were improved at 6 months. Implant 2 exhibited superior in vivo biocompatibility and higher optical clarity than Implant 1. PEG-diacrylamide-based IPN hydrogel is therefore a potential candidate for corneal inlays to correct refractive error.
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Affiliation(s)
- Xiao Wei Tan
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
| | - Laura Hartman
- Department of Chemical Engineering, Stanford University, Stanford, CA USA
| | - Kim Peng Tan
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
| | - Rebekah Poh
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
| | - David Myung
- Department of Chemical Engineering, Stanford University, Stanford, CA USA
- Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Luo Luo Zheng
- Department of Ophthalmology, Stanford University, School of Medicine, Stanford, CA USA
| | - Dale Waters
- Department of Chemical Engineering, Stanford University, Stanford, CA USA
| | - Jaan Noolandi
- Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Roger W. Beuerman
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, Stanford, CA USA
| | | | - Donald TH Tan
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Clinical Sciences, Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore
| | - Jodhbir S. Mehta
- Tissue Engineering and Stem Cell Research Group, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Clinical Sciences, Duke-NUS Graduate Medical School, National University of Singapore, Singapore, Singapore
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41
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Liao Q, Tsui A, Billington S, Frank CW. Extruded foams from microbial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and its blends with cellulose acetate butyrate. POLYM ENG SCI 2012. [DOI: 10.1002/pen.23087] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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42
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Abstract
The orientation of a monoclonal, anti-streptavidin human IgG1 antibody on a model hydrophobic, CH(3)-terminated surface (1-dodecanethiol self-assembled monolayer on gold) was studied by monitoring the mechanical coupling between the adsorbed layer and the surface as well as the binding of molecular probes to the antibodies. In this study, the streptavidin antigen was used as a probe for the Fab portions of the antibody, while bacteria-derived Protein G' was used as a probe for the Fc region. Bovine serum albumin (BSA) acted as a blocking protein. Monolayer coverage occurred around 468 ng/cm(2). Below 100 ng/cm(2), antibodies were found to adsorb flat-on, tightly coupled to the surface and unable to capture their antigen, whereas the Fc region was able to bind Protein G'. At half-monolayer coverage, there was a transition in the mechanism of adsorption to allow for vertically oriented antibodies, as evidenced by the binding of both Protein G' and streptavidin as well as looser mechanical coupling with the surface. Monolayer coverage was characterized by a reduced level in probe binding per antibody and an even less rigid coupling to the surface.
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Affiliation(s)
- Meredith E Wiseman
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
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44
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Waters DJ, Engberg K, Parke-Houben R, Ta CN, Jackson AJ, Toney MF, Frank CW. Structure and Mechanism of Strength Enhancement in Interpenetrating Polymer Network Hydrogels. Macromolecules 2011. [DOI: 10.1021/ma200693e] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dale J. Waters
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
| | - Kristin Engberg
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
| | - Rachel Parke-Houben
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
| | - Christopher N. Ta
- Department of Ophthalmology, Stanford University School of Medicine, 300 Pasteur Drive Stanford, California 94305-5025, United States
| | - Andrew J. Jackson
- NIST Center for Neutron Research, National Institute of Standards and Technology,100 Bureau Drive, Gaithersburg, Maryland 20899-6102, United States
- Department of Chemical Engineering, University of Delaware, 150 Academy Street, Newark, Delaware 19716, United States
| | - Michael F. Toney
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025-7015, United States
| | - Curtis W. Frank
- Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States
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45
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Hartmann L, Watanabe K, Zheng LL, Kim CY, Beck SE, Huie P, Noolandi J, Cochran JR, Ta CN, Frank CW. Toward the development of an artificial cornea: improved stability of interpenetrating polymer networks. J Biomed Mater Res B Appl Biomater 2011; 98:8-17. [PMID: 21504051 DOI: 10.1002/jbm.b.31806] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 10/31/2010] [Accepted: 11/09/2010] [Indexed: 11/11/2022]
Abstract
A novel interpenetrating network (IPN) based on poly(ethylene glycol) (PEG) and poly(acrylic acid) was developed and its use as an artificial cornea was evaluated in vivo. The in vivo results of a first set of corneal inlays based on PEG-diacrylate precursor showed inflammation of the treated eyes and haze in the corneas. The insufficient biocompatibility could be correlated to poor long-term stability of the implant caused by hydrolytic degradation over time. Adapting the hydrogel chemistry by replacing hydrolysable acrylate functionalities with stable acrylamide functionalities was shown to increase the long-term stability of the resulting IPNs under hydrolytic conditions. This new set of hydrogel implants now shows increased biocompatibility in vivo. Rabbits with corneal inlay implants are healthy and have clear cornea and non-inflamed eyes for up to 6 months after implantation.
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Affiliation(s)
- Laura Hartmann
- Department of Ophthalmology, School of Medicine, Stanford University, Palo Alto, California 94303, USA
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46
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Cho NJ, Jackman JA, Liu M, Frank CW. pH-driven assembly of various supported lipid platforms: a comparative study on silicon oxide and titanium oxide. Langmuir 2011; 27:3739-48. [PMID: 21366275 DOI: 10.1021/la104348f] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Supported lipid platforms are versatile cell membrane mimics whose structural properties can be tailored to suit the application of interest. By identifying parameters that control the self-assembly of these platforms, there is potential to develop advanced biomimetic systems that overcome the surface specificity of lipid vesicle interactions under physiological conditions. In this work, we investigated the adsorption kinetics of vesicles onto silicon and titanium oxides as a function of pH. On each substrate, a planar bilayer and a layer of intact vesicles could be self-assembled in a pH-dependent manner, demonstrating the role of surface charge density in the self-assembly process. Under acidic pH conditions where both zwitterionic lipid vesicles and the oxide films possess near-neutral electric surface charges, vesicle rupture could occur, demonstrating that the process is driven by nonelectrostatic interactions. However, we observed that the initial rupturing process is insufficient for propagating bilayer formation. The role of electrostatic interactions for propagating bilayer formation differs for the two substrates; electrostatic attraction between vesicles and the substrate is necessary for complete bilayer formation on titanium oxide but is not necessary on silicon oxide. Conversely, in the high pH regime, repulsive electrostatic interactions can result in the irreversible adsorption of intact vesicles on silicon oxide and even a reversibly adsorbed vesicle layer on titanium oxide. Together, the results show that pH is an effective tool to modulate vesicle-substrate interactions in order to create various self-assembled lipid platforms on hydrophilic substrates.
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Affiliation(s)
- Nam-Joon Cho
- Department of Chemical Engineering and Division of Gastroenterology and Hepatology, School of Medicine, Stanford University, Stanford, California 94305, United States
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48
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Kleideiter G, Prucker O, Bock H, Frank CW, Lechner MD, Knoll W, Prucker O, Kleideiter G. Polymer thin film properties as a function of temperature and pressure. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/masy.19991450111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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49
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Feller BE, Kellis JT, Cascão-Pereira LG, Robertson CR, Frank CW. Interfacial biocatalysis on charged and immobilized substrates: the roles of enzyme and substrate surface charge. Langmuir 2011; 27:250-263. [PMID: 21128607 DOI: 10.1021/la103079t] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An enzyme charge ladder was used to examine the role of electrostatic interactions involved in biocatalysis at the solid-liquid interface. The reactive substrate consisted of an immobilized bovine serum albumin (BSA) multilayer prepared using a layer-by-layer technique. The zeta potential of the BSA substrate and each enzyme variant was measured to determine the absolute charge in solution. Enzyme adsorption and the rate of substrate surface hydrolysis were monitored for the enzyme charge ladder series to provide information regarding the strength of the enzyme-substrate interaction and the rate of interfacial biocatalysis. First, each variant of the charge ladder was examined at pH 8 for various solution ionic strengths. We found that for positively charged variants the adsorption increased with the magnitude of the charge until the surface became saturated. For higher ionic strength solutions, a greater positive enzyme charge was required to induce adsorption. Interestingly, the maximum catalytic rate was not achieved at enzyme saturation but at an invariable intermediate level of adsorption for each ionic strength value. Furthermore, the maximum achievable reaction rate for the charge ladder was larger for higher ionic strength values. We propose that diffusion plays an important role in interfacial biocatalysis, and for strong enzyme-substrate interaction, the rate of diffusion is reduced, leading to a decrease in the overall reaction rate. We investigated the effect of substrate charge by varying the solution pH from 6.1 to 8.7 and by examining multiple ionic strength values for each pH. The same intermediate level of adsorption was found to maximize the overall reaction rate. However, the ionic strength response of the maximum achievable rate was clearly dependent on the pH of the experiment. We propose that this observation is not a direct effect of pH but is caused by the change in substrate surface charge induced by changing the pH. To prove this hypothesis, BSA substrates were chemically modified to reduce the magnitude of the negative charge at pH 8. Chemical modification was accomplished by the amidation of aspartic and glutamic acids to asparagine and glutamine. The ionic strength response of the chemically modified substrate was considerably different than that for the native BSA substrate at an identical pH, consistent with the trend based on substrate surface charge. Consequently, for substrates with a low net surface charge, the maximum achievable catalytic rate of the charge ladder was relatively independent of the solution ionic strength over the range examined; however, at high net substrate surface charge, the maximum rate showed a considerable ionic strength dependence.
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Affiliation(s)
- Bob E Feller
- Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, United States
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Srubar III WV, Michel AT, Criddle CS, Frank CW, Billington SL. Engineered Biomaterials for Construction: A Cradle-to-Cradle Design Methodology for Green Material Development. ACTA ACUST UNITED AC 2011. [DOI: 10.18848/1832-2077/cgp/v07i05/54992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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