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Balaceanu A, Demco DE, Möller M, Pich A. Microgel Heterogeneous Morphology Reflected in Temperature-Induced Volume Transition and 1H High-Resolution Transverse Relaxation NMR. The Case of Poly(N-vinylcaprolactam) Microgel. Macromolecules 2011. [DOI: 10.1021/ma200103y] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sudha JD, Pich A, Reena VL, Sivakala S, Adler HJP. Water-dispersible multifunctional polyaniline-laponite-keggin iron nanocomposites through a template approach. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm13494a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Agrawal M, Gupta S, Pich A, Zafeiropoulos NE, Rubio-Retama J, Jehnichen D, Stamm M. Template-assisted fabrication of magnetically responsive hollow titania capsules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17649-17655. [PMID: 20949923 DOI: 10.1021/la103504e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This study reports on the fabrication of magnetically responsive hollow titania capsules by confining the superparamagnetic Fe(3)O(4) nanoparticles within a hollow and porous titania (TiO(2)) shell. The employed protocol involves precipitation of titania shell on the magnetite (Fe(3)O(4)) encapsulated polystyrene beads followed by the calcination of resulting composite particles at elevated temperature. Scanning electron microscopy and transmission electron microscopy reveal the presence of a thick, complete but irregular titania shell on the magnetic polystyrene beads after the templating process. Electron energy loss mapping image analysis has been employed to investigate the spatial distribution of titania and magnetite phases of magnetic hollow titania capsules (MHTCs). Magnetic characterization indicates that both titania-coated magnetic polystyrene beads (TMPBs) and MHTCs are superparamagnetic in nature with the saturated magnetizations of 5.6 and 8.1 emu/g, respectively. X-ray diffraction (XRD) analysis reveals that titania shell of these capsules is composed of photoactive anatase phase. Nitrogen adsorption-desorption analysis has been employed to estimate the specific surface area and the average pore diameter of the fabricated hollow structures. Photocatalytic activity of the fabricated MHTCs for the photodegradation of rhodamine 6G dye has been demonstrated and compared with that of bulk titania nanoparticles.
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Türke A, Fischer WJ, Adler HJ, Pich A. Microwave-assisted synthesis of hybrid colloids for design of conducting films. POLYMER 2010. [DOI: 10.1016/j.polymer.2010.08.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kettel M, Dierkes F, Schäfer K, Möller M, Pich A. Synthese von reaktionsfähigen Cyclodextrin-Mikrogelen durch Batch-Fällungspolymerisation. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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207
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Schäfer K, Wang H, Pich A, Möller M, Damm C, Ernst S. Lumineszierende Kunststofffilme und -filamente für Warn- und Sicherheitssysteme. CHEM-ING-TECH 2010. [DOI: 10.1002/cite.201050105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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208
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Thümmler K, Häntzschel N, Skapenko A, Schulze-Koops H, Pich A. Surfactant-free poly(styrene-co-glycidyl methacrylate) particles with surface-bound antibodies for activation and proliferation of human T cells. Bioconjug Chem 2010; 21:867-74. [PMID: 20426436 DOI: 10.1021/bc900402d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this article, we present our results on the design of new polymeric carriers for antibodies. Polymer colloids based on poly(styrene-co-glycidyl methacrylate) were synthesized by surfactant-free emulsion polymerization. Obtained polymer particles stabilized by grafted poly(ethylene glycol) (PEG) chains and carrying active epoxy groups were used for the covalent immobilization of activating antibodies against the human surface proteins CD (cluster of differentiation) 3 and CD28. The particle-antibody conjugates were employed for the stimulation of human CD4 memory T cells. This was analyzed by the up-regulation of the activation markers CD69 and CD25 on T cells and T cell proliferation as assessed by the dilution of a fluorescent dye on dividing daughter T cells. The particle-antibody conjugates were able to stimulate T cells at least as efficiently as conventional methods, e.g., surface-immobilized antibodies. Furthermore, an increase of the PEG chain length of the particles decreased the efficiency of the particle-antibody conjugates to activate T cells.
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Schachschal S, Balaceanu A, Melian C, Demco DE, Eckert T, Richtering W, Pich A. Polyampholyte Microgels with Anionic Core and Cationic Shell. Macromolecules 2010. [DOI: 10.1021/ma100184h] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cheng C, Zhu X, Pich A, Möller M. Aqueous microgels modified by wedge-shaped amphiphilic molecules: hydrophilic microcontainers with hydrophobic nanodomains. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:4709-4716. [PMID: 19961194 DOI: 10.1021/la903588p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A simple route for the design of hydrophilic microgels comprising inner hydrophobic nanodomains has been developed based on postmodification of microgels by complexation of wedge-shaped amphiphilic molecules with complementary functional groups. Aqueous microgels functionalized with imidazole groups were transferred into an organic medium, where imidazole groups were neutralized by water-insoluble wedge-shaped molecules bearing a sulfonic acid group at the tip of the wedge and a large hydrocarbon body. After redispersion of the modified microgel particles into the aqueous phase, wedge-shaped amphiphiles ionically attached to the polymer chains self-assembled into discrete nanodomains in the interior of the polymer colloids due to the hydrophobic attraction force. The loading of the wedge-shaped molecules into microgels can be controlled by variation of the amount of imidazole groups integrated into the microgel network as well as the neutralization degree. The experimental results suggested that incorporation of hydrophobic domains into hydrophilic colloids induced dramatic changes of their properties such as swelling degree, surface charge, and responsiveness toward temperature and pH. Finally, we demonstrated that internally hydrophobized microgel particles are very effective in uptake of hydrophobic molecules in aqueous media.
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Agrawal M, Pich A, Gupta S, Zafeiropoulos NE, Formanek P, Jehnichen D, Stamm M. Tailored growth of In(OH)(3) shell on functionalized polystyrene beads. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:526-532. [PMID: 19785399 DOI: 10.1021/la9021933] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fabrication of organic-inorganic composite particles with tailored size, shape, and morphology has been attracting great attention from researchers because of their fascinating properties and applications in a variety of potential fields. In this study, we report on the fabrication of PS-In(OH)(3) (polystyrene-indium hydroxide) composite particles by hydrolyzing the In(OC(3)H(7))(3) (indium isopropoxide) salt in the presence of beta-diketone functionalized PS colloidal particles. A systematic investigation of the employed reaction conditions allowed us to tune the morphology, size, and In(OH)(3) content of the PS-In(OH)(3) composite particles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results illustrate that variation in the employed concentration of the In(OC(3)H(7))(3) salt in reaction media can effectively tune the morphology of resulting composite particles between "core-shell" and "raspberry-like". X-ray diffraction (XRD) analysis confirms the phase purity of In(OH)(3) nanoparticles precipitated on the surface of PS beads. Colloidal stability of the composite particles has been found to be reduced with increasing the deposited amount of In(OH)(3) nanoparticles. Thermogravimetric analysis (TGA) suggests a continuous increase in the deposited amount of In(OH)(3) nanoparticles with increasing concentration of In(OC(3)H(7))(3) salt in reaction media. The resulting PS-In(OH)(3) composite particles are envisioned to be used in a myriad of potential applications including fabrication of optoelectronic devices, absorption/separation supporting material, catalysts, and hydrophobic surfaces.
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Berger S, Ornatsky O, Baranov V, Winnik MA, Pich A. Hybrid nanogels by encapsulation of lanthanide-doped LaF3 nanoparticles as elemental tags for detection by atomic mass spectrometry. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00075b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Pich A, Richtering W. Microgels by Precipitation Polymerization: Synthesis, Characterization, and Functionalization. CHEMICAL DESIGN OF RESPONSIVE MICROGELS 2010. [DOI: 10.1007/12_2010_70] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Pich A, Riera L, Sismondi F, Godio L, Davico Bonino L, Marmont F, Francia di Celle P. JAK2V617F activating mutation is associated with the myeloproliferative type of chronic myelomonocytic leukaemia. J Clin Pathol 2009; 62:798-801. [PMID: 19734476 DOI: 10.1136/jcp.2009.065904] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Chronic myelomonocytic leukaemia (CMML) is a haematopoietic malignancy with heterogeneous clinical and morphological features. It is classified in the World Health Organization myeloproliferative-myelodysplastic overlap category. JAK2(V617F) mutation can be found in a large percentage of patients with myeloproliferative neoplasms. AIMS To investigate the association between JAK2(V617F) mutation and clinical, haematological and bone marrow histological features in CMML and to verify whether the mutation is associated with the myeloproliferative type of the disease. METHODS 78 consecutive patients with newly diagnosed CMML from 2004 to 2008 were included in the study. JAK2(V617F) mutation was assessed using direct sequencing of exon 14 or by allele-specific PCR from total peripheral blood or bone marrow samples. RESULTS JAK2(V617F) mutation was identified in eight cases (10.2%). All patients with the mutation presented with splenomegaly and had a significantly higher haemoglobin level and neutrophil count than patients without the mutation. All bone marrow biopsies of JAK2(V617F)-mutated CMML showed increased erythropoiesis, a marked myeloid and megakaryocytic hyperplasia with occasionally clustered megakaryocytes, and a mild or moderate (grade 1 or 2) fibrosis; six cases showed an increased number of dilated sinusoids and reactive lymphoid nodules. CONCLUSIONS The results indicate that JAK2(V617F) mutation is associated with clinical and morphological features of the myeloproliferative type of CMML. Therefore, JAK2 mutation analysis together with bone marrow morphology could help in a more appropriate classification of the disease.
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Agrawal M, Zafeiropoulos NE, Gupta S, Svetushkina E, Pionteck J, Pich A, Stamm M. A Novel Approach for Mixing ZnO Nanoparticles into Poly(ethyl methacrylate). Macromol Rapid Commun 2009; 31:405-10. [DOI: 10.1002/marc.200900584] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/12/2009] [Indexed: 11/11/2022]
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Piperno S, Gheber LA, Canton P, Pich A, Dvorakova G, Biffis A. Microgel electrospinning: A novel tool for the fabrication of nanocomposite fibers. POLYMER 2009. [DOI: 10.1016/j.polymer.2009.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Häntzschel N, Hund RD, Hund H, Schrinner M, Lück C, Pich A. Hybrid microgels with antibacterial properties. Macromol Biosci 2009; 9:444-9. [PMID: 19089873 DOI: 10.1002/mabi.200800219] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the present work, we have used aqueous microgels as containers for the deposition of silver nanoparticles (AgNPs). It has been shown that AgNPs can be effectively incorporated in the microgel interior during the in situ reduction of silver ions. Obtained hybrid microgels with variable AgNPs loading (from 1 to 12 wt.-%) have been used as antibacterial agents for two bacteria types. The experimental results indicate that porous microgel structure allows the release of the silver ions from the AgNPs surface into an aqueous phase. This ensures effective reduction in the number of bacterial colonies in test plates and complete bacteria killing. The antibacterial efficiency of the microgel particles increases with AgNPs loading.
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Muetzelburg M, Hofmann F, Just I, Pich A. Identification of biomarkers indicating cellular changes after treatment of neuronal cells with the C3 exoenzyme from Clostridium botulinum using the iTRAQ protocol and LC–MS/MS analysis☆. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:1344-51. [DOI: 10.1016/j.jchromb.2008.12.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 12/02/2008] [Accepted: 12/02/2008] [Indexed: 11/30/2022]
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220
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Pich A, Berger S, Ornatsky O, Baranov V, Winnik MA. The influence of PEG macromonomers on the size and properties of thermosensitive aqueous microgels. Colloid Polym Sci 2008. [DOI: 10.1007/s00396-008-1972-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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221
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Pich A, Zhang F, Shen L, Berger S, Ornatsky O, Baranov V, Winnik MA. Biocompatible hybrid nanogels. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:2171-5. [PMID: 19003827 PMCID: PMC2766817 DOI: 10.1002/smll.200801159] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Hain J, Schrinner M, Lu Y, Pich A. Design of multicomponent microgels by selective deposition of nanomaterials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:2016-2024. [PMID: 18949794 DOI: 10.1002/smll.200800149] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the present paper a method for the targeted deposition of different nanomaterials on aqueous microgels is described. In the first stage poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods are introduced into the microgel structure by in situ oxidative polymerization. In the second stage hydrogen tetrachloroaurate is used to transform PEDOT chains to an oxidized state in the microgel structure, leading to the fixation of chloroaurate anions on the surface of the PEDOT nanorods. The reduction of chloroaurate ions induces the formation of gold nanoparticles (AuNPs) predominantly located on the PEDOT surface. Obtained microgel/PEDOT/AuNP hybrid particles with different nanoparticle loadings exhibit superior colloidal stability and temperature sensitivity. The microgel/PEDOT/AuNP hybrid microgels exhibit extraordinary catalytic activity in aqueous media.
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Lu Y, Pich A, Adler HJP, Wang G, Rais D, Nešpůrek S. Composite polypyrrole-containing particles and electrical properties of thin films prepared therefrom. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.08.066] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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224
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Hain J, Pich A, Adler HJ, Rais D, Nešpůrek S. Electric Conductance of Films Prepared from Polymeric Composite Nanoparticles. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/masy.200850813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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225
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Schachschal S, Pich A, Adler HJ. Aqueous microgels for the growth of hydroxyapatite nanocrystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:5129-5134. [PMID: 18363417 DOI: 10.1021/la7037872] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In present article, we demonstrate that aqueous microgels can be used as containers for the in-situ synthesis of hydroxyapatite. The hydroxyapatite nanocrystals (HAp NCs) become integrated into microgels forming hybrid colloids. The HAp NCs loaded in the microgel can be varied over a broad range. The HAp NCs are localized within the microgel corona. The deposition of the inorganic nanocrystals decreases the colloidal stability of the microgels and leads to particle aggregation at high HAp NCs loading. Because of the strong interactions between HAp NCs and polymer chains, the swelling degree of microgels decreases, and temperature-sensitive properties disappear at high loading of the inorganic component. We demonstrate that hybrid colloids can be used as building blocks for the preparation of nanostructured films on solid substrates.
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Hain J, Eckert F, Pich A, Adler HJ. Macromol. Rapid Commun. 6/2008. Macromol Rapid Commun 2008. [DOI: 10.1002/marc.200890008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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227
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Hain J, Eckert F, Pich A, Adler HJ. Multi-Sensitive Microgels Filled with Conducting Poly(3,4-ethylenedioxythiophene) Nanorods. Macromol Rapid Commun 2008. [DOI: 10.1002/marc.200700653] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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228
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Navone R, Burlo P, Pich A, Pentenero M, Broccoletti R, Marsico A, Gandolfo S. The impact of liquid-based oral cytology on the diagnosis of oral squamous dysplasia and carcinoma. Cytopathology 2008; 18:356-60. [PMID: 18031448 DOI: 10.1111/j.1365-2303.2006.00402.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Even though diagnostic oral exfoliative cytology is a useful, economical and practical tool in the diagnosis of oral dysplasia and carcinoma, it is not yet extensively used. The results of conventional exfoliative and liquid-based diagnostic cytology in oral potentially malignant lesions (PML) are herein reported and compared with the histological diagnosis. METHODS Either conventional (89) or liquid-based (384) exfoliative cytology was used for the diagnosis of oral dysplasia/carcinoma in 473 subjects and the results were compared with scalpel biopsy histology. Cells were collected using a Cytobrush device for conventional smears and with a dermatological curette for the liquid-based cytology. The 'curette technique' also allowed for the collection of 'accidental' tissue fragments, utilized as microbiopsies. RESULTS Histological diagnosis was squamous carcinoma in 96 of 473 cases, high-grade dysplasia (oral intraepithelial neoplasia two to three) in 24 and other lesions in 353 cases. The smears in the conventional cytology group were inadequate in 12.4%, with an 85.7% sensitivity and a 95.9% specificity. There were 8.8% of inadequate specimens in the liquid-based cytology group; sensitivity was 95.1% and specificity was 99.0%. CONCLUSIONS Although conventional cytology is useful when diagnosing oral PML (better sensitivity and predictive positive value if compared with the cervical smear test with similar specificity) and can improve the accuracy of histological diagnosis, liquid-based cytology gives better results, as it not only enhances both sensitivity and specificity, but also provides material for further investigation (AgNORs, DNA, microbiopsies, etc.).
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Agrawal M, Pich A, Gupta S, Zafeiropoulos NE, Simon P, Stamm M. Synthesis of novel tantalum oxide sub-micrometer hollow spheres with tailored shell thickness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:1013-1018. [PMID: 18171090 DOI: 10.1021/la702509j] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Sub-micrometer-sized hollow tantalum oxide (Ta2O5) spheres with tunable shell thickness and void size have been fabricated exploiting beta-diketone-functionalized polystyrene (PS) beads as sacrificial templates in a sol-gel process. First, a controlled precipitation of Ta2O5 nanoparticles was carried out on the template surface by hydrolyzing tantalum ethoxide (Ta(OEt)5) at room temperature, and subsequently, the polymer core was removed either via chemical treatment with toluene or calcination at 650 degrees C. The thickness of the tantala shell precipitated on the PS core during the coating process was tuned between 100 and 142 nm by varying the concentration of tantala precursor in the reaction media. The obtained Ta2O5-coated PS particles and hollow microspheres were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Due to the unique optical and dielectric properties, these nanostructured materials are envisaged to be used in applications such as novel building blocks for the fabrication of advanced materials, surface coatings, catalysts, and drug delivery systems.
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Agrawal M, Pich A, Zafeiropoulos NE, Stamm M. Fabrication of hollow titania microspheres with tailored shell thickness. Colloid Polym Sci 2008. [DOI: 10.1007/s00396-007-1833-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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231
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Shen L, Pich A, Fava D, Wang M, Kumar S, Wu C, Scholes GD, Winnik MA. Loading quantum dots into thermo-responsive microgels by reversible transfer from organic solvents to water. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b713253k] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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232
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Agrawal M, Pich A, Gupta S, Zafeiropoulos NE, Rubio-Retama J, Simon F, Stamm M. Temperature sensitive hybrid microgels loaded with ZnO nanoparticles. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b802102c] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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233
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Häntzschel N, Zhang F, Eckert F, Pich A, Winnik MA. Poly(N-vinylcaprolactam-co-glycidyl methacrylate) aqueous microgels labeled with fluorescent LaF3:Eu nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:10793-800. [PMID: 17854211 DOI: 10.1021/la701691g] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We describe the synthesis and properties of functional microgel particles based on poly(N-vinylcaprolactam-co-glycidyl methacrylate) (PVCL/PGMA) copolymer. A series of colloidally stable microgel particles with a range of glycidyl methacrylate content were prepared by surfactant-free heterophase polymerization in water. The microgel particles obtained had hydrodynamic radii between 250 and 350 nm and were fairly monodisperse in size; however, a broadening of the particle size distribution was observed for samples with a low GMA content. The PVCL/PGMA microgel particles exhibit thermally responsive reversible changes in diameter in water, and the swelling degree increased with the PVCL fraction in the copolymer structure. These microgels were then modified with photoluminescent europium-doped lanthanum fluoride nanoparticles (LaF3:Eu-AEP) through reaction of the 2-aminoethyl phosphate surface ligands with epoxy groups present in the microgel. These hybrid microgels were colloidally stable and thermally responsive in aqueous solution.
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Hain J, Pich A, P. Adler HJ. Composite Particles: Design of Hybrid Materials on the Nano-Scale. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/masy.200750820] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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235
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Hass R, Lueck H, von Wasielewski R, Jin H, Pich A, Kuehnle H, Grothuesmann D, Hille U, Bertram C. Altered chemotherapeutic response of primary human breast cancer epithelial cells (HBCEC) and breast cancer cell lines. J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.11506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
11506 Background: A novel technique to obtain individual primary cultures of human breast cancer biopsies was filed for patent (PCT/DE 2006/000608). The different individualized HBCEC (human breast cancer epithelial cell) cultures will be characterized and chemotherapeutic effects will be compared to established breast cancer cell lines. Methods: Primary HBCEC from 20 different breast cancer patients were characterized for epithelial cell and tumor markers by immunofluorescence and PCR. Following treatment with 1μM epirubicin for 1h up to 72h differences in protein expression patterns were compared to the similarly treated MCF-7 cell line by 2D gel electrophoresis. Differentially expressed protein spots were identified by mass spectrometry and confirmed by appropriate Western blot analysis. Results: Characterization of primary HBCEC revealed continuous mitosis and cell cycle progression for more than one year in culture with no significant contamination by fibroblasts or other cell types. Whereby HBCEC underwent cell death within 72h of epirubicin treatment analysis by 2D gel and subsequent protein identification by MALDI-TOF/TOF mass spectrometry exhibited a variety of differences compared to MCF-7 cells including HSP27 and prohibitin. Appropriate Western blots confirmed these differences and revealed altered expression levels for HSP27 and prohibitin in the course of epirubicin exposure in HBCEC and MCF-7 cells, respectively, suggesting altered signalling pathways in either primary breast cancer cells or the tumor cell line. Conclusions: Individualized primary HBCEC from various patients could provide a cellular platform beyond breast cancer cell lines, which eventually meet the requirements for an appropriate breast cancer testing system including the characterization of biomarkers and the identification of potential molecular targets. No significant financial relationships to disclose.
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Bhattacharya S, Eckert F, Boyko V, Pich A. Temperature-, pH-, and magnetic-field-sensitive hybrid microgels. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2007; 3:650-7. [PMID: 17340664 DOI: 10.1002/smll.200600590] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We demonstrate a simple route for the preparation of novel hybrid particles with multiple sensitivities. Aqueous polymeric microgels are modified by magnetite nanoparticles in the preparation of temperature- and pH-sensitive hybrids with a high magnetic response. Up to 15 wt % of magnetite nanoparticles are loaded into microgels. The influence of the amount of magnetite in the microgel structure on the morphology and colloidal properties is discussed. The presence of the magnetite nanoparticles in the microgel decreases its degree of swelling and shifts the volume phase-transition temperature to higher values. Nanostructured composite films with controlled morphologies can be prepared by water evaporation and deposition of the hybrid microgels on a solid substrate.
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Lu Y, Spyra P, Mei Y, Ballauff M, Pich A. Composite Hydrogels: Robust Carriers for Catalytic Nanoparticles. MACROMOL CHEM PHYS 2007. [DOI: 10.1002/macp.200600534] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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238
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Pich A, Karak A, Lu Y, Ghosh AK, Adler HJP. Hybrid Microgels Containing Gold Nanoparticles. E-POLYMERS 2006. [DOI: 10.1515/epoly.2006.6.1.226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIn present paper we report on a preparation of hybrid microgels filled with gold nano-particles (AuNPs). Temperature-sensitive VCL/AAEM microgels have been used as containers for deposition of Au by in situ formation of gold nano-particles. Synthesis of AuNPs has been performed by two methods: a) reduction of chloroauric acid with sodium borhydride and b) reduction of chloroauric acid by sodium citrate under ultrasonic agitation. In both cases AuNPs were deposited directly into microgels leading to formation of composite particles which exhibit temperature-sensitive properties, tunable gold contents and high colloidal stability. The influence of Au load on microgel size, morphology, swellingdeswelling behaviour and stability is discussed.
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Pich A, Karak A, Lu Y, Ghosh AK, Adler HJP. Tuneable catalytic properties of hybrid microgels containing gold nanoparticles. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2006; 6:3763-9. [PMID: 17256327 DOI: 10.1166/jnn.2006.621] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A novel type of submicrometer-sized hybrid microgels containing gold nano-particles (AuNPs) has been tested as catalyst in reduction of 4-nitrophenol in aqueous medium. The influence of microgel concentration, gold content, as well as temperature of reaction medium on kinetics of 4-nitrophenol reduction process has been investigated. The pseudo-first-order kinetics was used to evaluate the catalytic reaction rate. It has been demonstrated that reaction rate of 4-nitrophenol reduction can be accelerated if the concentration of microgel in the reaction system or amount of gold nanoparticles loaded into microgels increases. Increase of reaction temperature resulted in rapid increase of reduction rate. Compared to pure gold nano-particles hybrid microgels at similar conditions reduce the activation energy of reduction process by a factor of 2. This indicates that localization of AuNPs within microgel template prevents their aggregation and therefore high catalytic activity can be preserved independently from reaction conditions. Additionally, polymeric template provides suitable environment for better mass transfer in present system that improves the catalyst efficiency.
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Wehnert F, Pich A. Fabrication of Thermo-Responsive Hybrid Hydrogels by In-Situ Mineralization and Self-Assembly of Microgel Particles. Macromol Rapid Commun 2006. [DOI: 10.1002/marc.200600482] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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241
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Pich A, Tessier A, Boyko V, Lu Y, Adler HJP. Synthesis and Characterization of Poly(vinylcaprolactam)-Based Microgels Exhibiting Temperature and pH-Sensitive Properties. Macromolecules 2006. [DOI: 10.1021/ma060985q] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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242
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Pich A, Lu Y, Adler HJP. Polymeric particles with conjugated polymer: Layer on its surface as effective adsorbents of amino acids. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.07.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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243
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Pich A, Bhattacharya S, Adler HJP, Wage T, Taubenberger A, Li Z, van Pee KH, Böhmer U, Bley T. Composite Magnetic Particles as Carriers for Laccase fromTrametes versicolor. Macromol Biosci 2006; 6:301-10. [PMID: 16572475 DOI: 10.1002/mabi.200500192] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper we report a study of laccase immobilisation on different kinds of carrier particles. The immobilisation of enzyme on the particle surface with respect to the immobilisation efficiency and the properties of the immobilised enzymes is discussed. The immobilisation of laccase on polystyrene particles bearing reactive beta-diketone groups is characterised by high efficiency, but grafting of the enzyme increases the stability of the colloidal system, which makes the separation/purification procedure difficult. Additionally, the extreme colloidal stability of the immobilisates hinders the application of such particles with immobilised enzymes in some applications where the recycling of the enzyme should be performed. It has been found that hybrid PS-AAEM particles equipped with maghemite show similar immobilisation efficiency to that of their analogues without maghemite and can additionally be manipulated in magnetic fields. The activity of the immobilised laccase is much higher in the pH region 5-7 and the temperature range 50-70 degrees C as compared with that of the free enzyme. Immobilised enzymes also exhibit much better storage stability.
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Yaremko ZM, Tkachenko NH, Bellmann C, Pich A. Redispergation of TiO2 particles in aqueous solutions. J Colloid Interface Sci 2006; 296:565-71. [PMID: 16387321 DOI: 10.1016/j.jcis.2005.09.044] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2005] [Revised: 09/19/2005] [Accepted: 09/20/2005] [Indexed: 11/28/2022]
Abstract
The colloidal stability of TiO2 dispersions in aqueous solutions was studied. Aqueous solutions of ATLAS G-3300 (1.57 x 10(-3) mol/l), TRITON X-100 (5 x 10(-5) mol/l), and PMAA (4 x 10(-6) and 5.81 x 10(-3) mol/l) have been used as medium for redispergation of TiO2 particles. Stability of dispersions was investigated at different pH values by two different methods. By using analytical centrifuge the sedimentation velocity of TiO2 particles was directly measured and by means of light scattering the particle size of dispersed particles has been monitored. Combination of these two methods allowed determination of the aggregation degree of TiO2 particles as well as structure of the aggregates formed in aqueous phase. It has been found that redispergation process does not provide complete separation of virgin TiO2 particles. Even in the case of stable dispersions some aggregates were found, which consisted of 2-4 virgin TiO2 particles. With increasing colloidal stability of dispersions aggregates appear to be spherically shaped. In the system where TRITON X-100 was used, formation of secondary aggregates by fusion of primary ones was observed.
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Pich A, Karak A, Lu Y, Ghosh AK, Adler HJP. Preparation of Hybrid Microgels Functionalized by Silver Nanoparticles. Macromol Rapid Commun 2006. [DOI: 10.1002/marc.200500761] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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246
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Pich A, Schiemenz N, Corten C, Adler HJP. Preparation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) particles in O/W emulsion. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.01.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pich A, Hain J, Lu Y, Boyko V, Prots Y, Adler HJ. Hybrid Microgels with ZnS Inclusions. Macromolecules 2005. [DOI: 10.1021/ma0505272] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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249
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Pich A, Bhattacharya S, Ghosh A, Adler HJ. Composite magnetic particles: 2. Encapsulation of iron oxide by surfactant-free emulsion polymerization. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.01.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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250
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Pich A, Bhattacharya S, Lu Y, Boyko V, Adler HJP. Temperature-sensitive hybrid microgels with magnetic properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:10706-10711. [PMID: 15544405 DOI: 10.1021/la040084f] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In the present paper, we report the preparation of hybrid temperature-sensitive microgels which include magnetite nanoparticles in their structure. Polymeric microgels have been prepared by surfactant-free emulsion copolymerization of acetoacetoxyethyl methacrylate (AAEM) and N-vinylcaprolactam (VCL) in water with a water-soluble azo-initiator. The obtained microgels possess a low critical solution temperature (LCST) in water solutions, with a rapid decrease of the particle size being observed at elevated temperatures. Magnetite was deposited directly into microgels, leading to the formation of composite particles which combine both temperature-sensitive and magnetic properties. The influence of magnetite load on microgel size, morphology, swelling-deswelling behavior, and stability is discussed.
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