51
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52
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Molnar A, Eisenberg A. Miscibility of polyamide-6 with lithium or sodium sulfonated polystyrene ionomers. Macromolecules 2002. [DOI: 10.1021/ma00047a032] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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53
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Williams J, Eisenberg A. Methyl Group Tunneling and Viscoelastic Relaxation in Poly(methyl methacrylate). Macromolecules 2002. [DOI: 10.1021/ma60064a017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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54
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Hara M, Eisenberg A. Miscibility enhancement via ion-dipole interactions. 1. Polystyrene ionomer/poly(alkylene oxide) systems. Macromolecules 2002. [DOI: 10.1021/ma00137a008] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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55
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Tobolsky AV, Eisenberg A, O'Driscoll KF. Spectrophotometric Determination of Styrene in Styrene-Methyl Methacrylate Copolymer. Anal Chem 2002. [DOI: 10.1021/ac60146a013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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56
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Liu Y, Quinn J, Rafailvoich MH, Sokolov J, Zhong X, Eisenberg A. Neutron Reflectivity Study of Poly(vinyl-4-pyridine)-Deuterated Polystyrene (P4VP-dPS) Diblock Brushes. Macromolecules 2002. [DOI: 10.1021/ma00122a048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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57
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58
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Navratil M, Eisenberg A. Ion Clustering and Viscoelastic Relaxation in Styrene-Based Ionomers. III. Effect of Counterions, Carboxylic Groups, and Plasticizers. Macromolecules 2002. [DOI: 10.1021/ma60037a017] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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59
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Eisenberg A, Teter L. The Viscoelastic Relaxation Mechanism of Inorganic Polymers. Amorphous Selenium1. J Am Chem Soc 2002. [DOI: 10.1021/ja01088a006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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60
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Boyle NG, McBrierty VJ, Eisenberg A. NMR investigation of molecular motion in Nafion membranes. Macromolecules 2002. [DOI: 10.1021/ma00235a016] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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61
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Hodge IM, Eisenberg A. Dielectric Properties of Styrene-Sodium Methacrylate Copolymers in the Glass Transition Region. Macromolecules 2002. [DOI: 10.1021/ma60062a001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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62
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Bosse F, Eisenberg A. Kinetics of Coil Overlap in Ionomer Blends by 1H NMR in DMSO-d6. 2. Mechanistic Aspects. Macromolecules 2002. [DOI: 10.1021/ma00088a028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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63
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64
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Rutkowska M, Eisenberg A. Ionomeric blends. 3. Miscibility enhancement via ionic interactions in polyurethane-styrene blends. Macromolecules 2002. [DOI: 10.1021/ma00134a050] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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65
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Eisenberg A, Navratil M. Ion Clustering and Viscoelastic Relaxation in Styrene-Based Ionomers. IV. X-Ray and Dynamic Mechanical Studies. Macromolecules 2002. [DOI: 10.1021/ma60037a018] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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66
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Rembaum A, Eisenberg A, Haack R. Equilibria between Metallic Sodium and Aromatic Hydrocarbons1. J Am Chem Soc 2002. [DOI: 10.1021/ja01088a039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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67
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Rembaum A, Eisenberg A, Haack R, Landel RF. Equilibria between Metallic Sodium and Aromatic Hydrocarbons. J Am Chem Soc 2002. [DOI: 10.1021/ja00981a004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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68
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Maysinger D, Berezovska O, Savic R, Soo PL, Eisenberg A. Block copolymers modify the internalization of micelle-incorporated probes into neural cells. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1539:205-17. [PMID: 11420118 DOI: 10.1016/s0167-4889(01)00110-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An important therapeutic concern is rate and extent of internalization of drugs into cells. Hydrophilic agents often internalize poorly and slowly, and highly lipophilic ones too rapidly. The incorporation of drugs into micelles allows regulation of their internalization parameters, and newly-described block copolymers can be selectively tailored to suit specific drugs. This report compares internalization of Cell Tracker CM-DiI (DiI), a highly lipophilic non-cytotoxic fluorescent probe in common use in biology, from the freely-presented (non-micelle-incorporated) and micelle-incorporated states. DiI was effectively incorporated (>60%) into 25-50 nm diameter spherical micelles made from polycaprolactone-b-polyethylene oxide block copolymer. Confocal microscopy was used to evaluate the internalization of DiI into mixed neuron-glia cultures (2-14 days in vitro, 2DIV-14DIV). Incorporation of DiI into micelles strikingly reduced the rate and extent of its internalization in both 2DIV and 14DIV cultures. Both the age of the cultures and the block copolymer employed to construct the micelles significantly influence the internalization of micelle-incorporated probe.
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69
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Luo L, Eisenberg A. Thermodynamic stabilization mechanism of block copolymer vesicles. J Am Chem Soc 2001; 123:1012-3. [PMID: 11456651 DOI: 10.1021/ja005824v] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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70
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White H, Pu Y, Rafailovich M, Sokolov J, King A, Giannuzzi L, Urbanik-Shannon C, Kempshall B, Eisenberg A, Schwarz S, Strzhemechny Y. Focused ion beam/lift-out transmission electron microscopy cross sections of block copolymer films ordered on silicon substrates. POLYMER 2001. [DOI: 10.1016/s0032-3861(00)00503-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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71
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Allen C, Eisenberg A, Mrsic J, Maysinger D. PCL-b-PEO micelles as a delivery vehicle for FK506: assessment of a functional recovery of crushed peripheral nerve. Drug Deliv 2000; 7:139-45. [PMID: 10989914 DOI: 10.1080/10717540050120179] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The aim of this work was to test in vivo a new block copolymer-based delivery system containing lipophilic drug FK506, known as Tacrolimus. Tacrolimus is currently used in clinics as an immunosupressant agent, and more recently it has been shown that it can exert neurotrophic effects. We prepared, characterized, and assessed polycaprolactone-b-polyethylenoxyde (PCL-b-PEO) micelles containing FK506 in vitro and in vivo. By using well-established animal model of peripheral nerve injury (crushed sciatic nerve), we show that the rate of functional recovery of injured nerve is significantly enhanced in rats treated with micellar FK506. These findings support the notion that PCL-b-PEO is a suitable polymer material for FK506 and suggest its wider applicability as a delivery vehicle for other biologically active, poorly soluble therapeutic agents.
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72
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Krückler JF, Eisenberg A, Krix M, Lötsch R, Pessel M, Trier HG. Rigid piston approximation for computing the transfer function and angular response of a fiber-optic hydrophone. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2000; 107:1994-2003. [PMID: 10790026 DOI: 10.1121/1.428483] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The transfer function of a fiber-optic hydrophone (FOH) is computed for various fiber core radii. The hydrophone is modeled as a rigid disk, with plane waves impinging at normal or oblique incidence. The total sound field is written as the sum of the incident field and the field diffracted from the hydrophone. The diffracted field is approximated by the field generated by a vibrating planar piston in an infinite rigid baffle. For normal incidence and a pointlike fiber core, an analytical solution is presented. For finite fiber core radii, and for oblique incidence, the transfer functions are computed numerically. The calculated transfer functions exhibit an oscillatory frequency dependency that is most pronounced for small fiber cores. The solution for a core radius of 2.5 microm can be very well approximated by the analytical solution for a pointlike core at frequencies of up to 30 MHz. The results for normal incidence can be directly employed to deconvolute ultrasonic pressure signals measured with an FOH. From the transfer functions for oblique incidence, the angular response of the hydrophone is calculated. The angular response obtained here differs significantly from the model commonly used for piezoelectric hydrophones. The effective hydrophone radius derived from the angular response shows a strong frequency dependency. For low frequencies, it is found to be larger than the outer fiber radius, whereas it generally lies between the outer radius and the fiber core radius for frequencies above 10 MHz.
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73
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Allen C, Han J, Yu Y, Maysinger D, Eisenberg A. Polycaprolactone-b-poly(ethylene oxide) copolymer micelles as a delivery vehicle for dihydrotestosterone. J Control Release 2000; 63:275-86. [PMID: 10601723 DOI: 10.1016/s0168-3659(99)00200-x] [Citation(s) in RCA: 298] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Block copolymer micelles formed from copolymers of poly(caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) were investigated as a drug delivery vehicle for dihydrotestosterone (DHT). The physical parameters of the PCL-b-PEO micelle-incorporated DHT were measured, including the loading capacity of the micelles for DHT, the apparent partition coefficient of DHT between the micelles and the external medium and the kinetics of the release of DHT from the micelle solution. The MTT survival assay was used to assess the in vitro biocompatibility of PCL-b-PEO micelles in HeLa cell cultures. The biological activity of the micelle-incorporated DHT was evaluated in HeLa cells which had been co-transfected with the expression vectors for the androgen receptor and the MMTV-LUC reporter gene. The PCL-b-PEO micelles were found to have a high loading capacity for DHT and the release profile of the drug from the micelle solution was found to be a slow steady release which continued over a 1-month period. The biological activity of the micelle-incorporated DHT was found to be fully retained.
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74
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Gavagan JE, DiCosimo R, Eisenberg A, Fager SK, Folsom PW, Hann EC, Schneider KJ, Fallon RD. A Gram-negative bacterium producing a heat-stable nitrilase highly active on aliphatic dinitriles. Appl Microbiol Biotechnol 1999. [DOI: 10.1007/s002530051574] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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75
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Hann EC, Eisenberg A, Fager SK, Perkins NE, Gallagher FG, Cooper SM, Gavagan JE, Stieglitz B, Hennessey SM, DiCosimo R. 5-Cyanovaleramide production using immobilized Pseudomonas chlororaphis B23. Bioorg Med Chem 1999; 7:2239-45. [PMID: 10579532 DOI: 10.1016/s0968-0896(99)00157-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A biocatalytic process for the hydration of adiponitrile to 5-cyanovaleramide has been developed which can be run to higher conversion, produces more product per weight of catalyst, and generates significantly less waste products than alternate chemical processes. The biocatalyst consists of Pseudomonas chlororaphis B23 microbial cells immobilized in calcium alginate beads. The cells contain a nitrile hydratase (EC 4.2.1.84) which catalyzes the hydration of adiponitrile to 5-cyanovaleramide with high regioselectivity, and with less than 5% selectivity to byproduct adipamide. Fifty-eight consecutive batch reactions with biocatalyst recycle were run to convert a total of 12.7 metric tons of adiponitrile to 5-cyanovaleramide. At 97% adiponitrile conversion, the yield of 5-cyanovaleramide was 13.6 metric tons (93% yield, 96% selectivity), and the total weight of 5-cyanovaleramide produced per weight of catalyst was 3150 kg/kg (dry cell weight).
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