H P Jennissen

University of Duisburg-Essen, Essen, North Rhine-Westphalia, Germany

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Publications (89)140.46 Total impact

  • PolyMerTech 2014, Merseburg, Germany; 06/2014
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    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):429. · 4.43 Impact Factor
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    T Sänger, AS Asran, M Laub, GHMichler, HP Jennissen
    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):458. · 4.43 Impact Factor
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    Journal of Tissue Engineering and Regenerative Medicine 06/2014; 8(1):432. · 4.43 Impact Factor
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    POLYCHAR 22 World Forum on Advanced Materials 7-11 April 2014, Stellenbosch, South Africa; 04/2014
  • S Lüers, M Laub, A Kirsch, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 09/2013; · 1.16 Impact Factor
  • T Sänger, M Laub, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 09/2013; · 1.16 Impact Factor
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    H P Jennissen, S Madenci, S Lüers, M Laub
    Biomedizinische Technik/Biomedical Engineering 09/2013; · 1.16 Impact Factor
  • K Zurlinden, M Laub, D-S Dohle, H P Jennissen
    Biomedizinische Technik/Biomedical Engineering 08/2012; · 1.16 Impact Factor
  • H P Jennissen, S Lüers, M Laub
    Biomedizinische Technik/Biomedical Engineering 08/2012; · 1.16 Impact Factor
  • H. P. Jennissen
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    ABSTRACT: The complete wetting of rough surfaces is only poorly understood, since the underlying phenomena can neither be described by the Cassie-Baxter nor the Wenzel equation. An experimental accessiblility by the sessile drop method is also very limited. The term “superhydrophilicity” was an attempt to understand the wetting of rough surfaces, but a clear definition is still forthcoming, mainly because non-superhydrophilic surfaces can also display a contact angle of zero. Since the Wilhelmy balance is based on force measurements, it offers a technology for obtaining signals during the whole wetting process. We have obtained evidence that additional forces occur during the complete wetting of rough surfaces and that mathematically contact angles for a hydrophilicity beyond the contact angle of zero can be defined by imaginary numbers. A hydrophilized TPS-surface obtained by chemical wettability switching from a superhydrophobic surface has been previously characterized by dynamic imaginary contact angles of 20i°–21i° and near-zero hysteresis. Here an extremely high wetting rate is demonstrated reaching a virtual imaginary contact angle of ΘV,Adv > 3.5i° in less than 210 ms. For a rough surface displaying imaginary contact angles and extremely high wetting rates we suggest the term hyperhydrophilicity. Although, as will be shown, the physical basis of imaginary contact angles is still unclear, they significantly expand our methodology, the range of wettability measurements and the tools for analyzing rough hydrophilic surfaces. They may also form the basis for a new generation of rationally constructed medicinal surfaces. Die vollkommene Benetzung rauer Oberflächen ist nur wenig verstanden, da eine Beschreibung durch die Cassie-Baxter- oder Wenzel-Geleichung nicht möglich ist. Ein experimenteller Zugang durch die Tropfenmethode ist auch sehr beschränkt. Der Ausdruck “Superhydrophilizität” versucht die Benetzung rauer Oberflächen zu beschreiben, aber bis heute liegt keine klare Definition vor, wohl auch, weil auch nicht-superhydrophile Oberflächen einen Kontaktwinkel von Null aufweisen können. Da die Wilhylmy Methode auf Kraftmessungen beruht, bietet sie die Technologie, Daten während des gesamten Benetzungsprozesses aufzunehmen. Wir haben Hinweise, dass zusätzliche Kräfte während der Benetzunng rauer Oberflächen auftreten, und dass Kontaktwinkel für eine Hydrophilie jenseits eines Kontaktwinkels von Null durch imaginäre Zahlen definiert werden können. Eine hydrophilierte TPS-Oberfläche, die durch eine chemische Benetzungsumkehr einer superhydrophoben Oberfläche erhalten wurde, wurde schon früher durch dynamische imaginäre Kontaktwinkel von 20i°–21i° und einer Hysterese nahe Null charakterisiert. Hier wird nun eine extreme Benetzungsgeschwindigkeit für der Erreichung eines virtuellen Kontaktwinkels von ΘV,Adv > 3.5i° innerhalb von 210 ms aufgezeigt. Für raue Oberflächen, die imaginäre Kontaktwinkel und extrem hohe Benetzungsraten aufweisen, schlagen wir den Begriff Hyperhydrophilie vor. Obwohl wie gezeigt wird, die physikalischen Grundlagen für imaginärere Kontaktwinkel noch unklar sind, erweitern sie erheblich die Methodologie, den Bereich der Beneztbarkeitsmessungen sowie das Instrumentarium für die Analyse rauer hydrophiler Oberflächen. Ferner können die neuen Kontaktwinkel die Schaffung einer neuen Generation rational konstruierter Oberflächen für die Medizin ermöglichen.
    Materialwissenschaft und Werkstofftechnik 08/2012; 43(8). · 0.51 Impact Factor
  • H. P. Jennissen
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    ABSTRACT: Although Wilhelmy balance measurements have been reported to yield undefined values of the type cos θ > 1, this phenomenon often goes unnoticed because commercial instruments fail to report this error, listing a contact angle of zero instead. On rough superhydrophilic surfaces such “undefined” values appear much more frequent, but a mathematical framework for evaluation and quantification is lacking. A solution to the problem of cos θ > 1 was found by implementing the imaginary number i. It will be shown that both the classical and novel contact angles can be described by numbers in an imaginary space hitherto not accessible to the Wilhelmy and Young equation system. It will be exemplified that Wilhelmy balance data classed as undefined because of cos θ > 1, can easily be converted to imaginary numbers allowing the extrapolation of a novel imaginary advancing θai,AH2O = 0.36i rad and receding contact angle θai,RH2O = 0.37i rad at zero immersion depth as in classical tensiometry. The two imaginary angles compare to classical angles of ∣20°∣–∣25°∣ . The postulated core wettability range for superhydrophilicity in the special case of the “inverse lotus effect” is suggested to extend from the classical angle of cos (10°) to the imaginary angle of cos (0.37i rad). Knowledge obtained from such analyses should be of use in constructing novel artificial surfaces of extreme wettability, e. g. superhydrophilicity, not only in the medical field of implantology but also in chemistry, physics and engineering.Obwohl es seit langem Berichte über Wilhelmy-Waage Messungen gibt, die zu undefinierten Werten der Art cos θ > 1 führten, wird dieses Phänomen häufig übersehen, weil die kommerziellen Geräte statt einer Fehlermeldung den Kontaktwinkel Null ausgeben. Auf rauhen superhydrophilen Oberflächen scheinen “undefinierte” Werte sehr viel häufiger vorzukommen als bisher bekannt, wobei ein mathematisches Gerüst für eine Auswertung und Quantifizierung fehlt. Eine Lösung des Problems cos θ > 1 wurde durch die Verwendung der imaginären Zahl I gefunden. Es wird gezeigt, dass sowohl die klassischen als auch neuartige Kontaktwinkel durch Zahlen im imaginären Raum, für den es bisher für die Wilhelmy- und Young-Gleichung keinen Zugang gab, beschrieben werden können. In einem Beispiel wird gezeigt, dass Wilhelmy-Waage Daten, die bisher wegen cos θ > 1 als undefiniert galten, leicht in imaginäre Zahlen konvertiert werden können, die es erlauben einen neuartigen imaginären Vorrück- θai,AH2O = 0.36i rad und Rückzugswinkel θai,RH2O = 0.37i rad bei der Eintauchtiefe Null zu extrapolieren wie bei der klassischen Tensiometrie. Die beiden Winkel sind vergleichbar den klassischen Winkeln von ∣20°∣–∣25° ∣ . Der postulierte Kernbereich für die Benetzbarkeit im Spezialfall des “inversen Lotus-Effektes” erstreckt sich vom klassischen Kontaktwinkel cos (10°) bis zum imaginären Winkel von cos (0.37i rad). Neue Erkenntnisse, die von solchen Analysen gewonnen werden können, sollten von Bedeutung für die Herstellung neuer künstlicher Oberflächen mit extremer Benetzbarkeit z.B. Superhydrophilizität nicht nur im Medizinischen Bereich der Implantologie sondern auch in der Chemie, Physik und den Ingenieurwissenschaften sein.
    Materialwissenschaft und Werkstofftechnik 12/2011; 42(12). · 0.51 Impact Factor
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    H.P. Jennissen, S. Lüers
    Materialwissenschaft und Werkstofftechnik 04/2011; 42(4). · 0.51 Impact Factor
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    H.P. Jennissen
    Materialwissenschaft und Werkstofftechnik 04/2011; 42(4). · 0.51 Impact Factor
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    ABSTRACT: A functionalization is required for calcium phosphate-based bone substitute materials to achieve an entire bone remodeling. In this study it was hypothesized that a tailored composite of tricalcium phosphate and a bioactive glass can be loaded sufficiently with rhBMP-2 for functionalization. A composite of 40 wt% tricalcium phosphate and 60 wt% bioactive glass resulted in two crystalline phases, wollastonite and rhenanite after sintering. SEM analysis of the composite's surface revealed a spongious bone-like morphology after treatment with different acids. RhBMP-2 was immobilized non-covalently by treating with chrome sulfuric acid (CSA) and 3-aminopropyltriethoxysilane (APS) and covalently by treating with CSA/APS, and additionally with 1,1'-carbonyldiimidazole. It was proved that samples containing non-covalently immobilized rhBMP-2 on the surface exhibit significant biological activity in contrast to the samples with covalently bound protein on the surface. We conclude that a tailored composite of tricalcium phosphate and bioactive glass can be loaded sufficiently with BMP-2.
    Journal of Materials Science Materials in Medicine 02/2011; 22(4):763-71. · 2.14 Impact Factor
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    ABSTRACT: The main objectives of the study described below were of two-fold nature: (1) to examine if rhBMP-2-biocoated implants in a pig model could lead to ectopic bone formation and (2) if quantitative and/or qualitative differences could be found between adhesively and covalently bonded BMP II using the scintigraphic method. In order to examine these central questions, 26 Göttingen minipigs were allocated to three groups with a control group (n=7) and two study groups (n=9 each) receiving one of three implant types: (a) chromosulfuric acid treated titanium surface as control, (b) non-covalently bonded BMP-2, and (c) covalently bonded and immobilized rhBMP-2. Each animal received four barbell-shaped implants, one in the proximal and distal metaphysis of each femur. The scintigraphic analyses were conducted after four, eight, and 12 weeks postoperatively. The visual (qualitative) analysis failed to show ectopic bone formation in any of the three groups. The statistical analysis of the relative values for bone formation yielded no significant differences between the groups, although the limitation in the applied methods do not enable one to draw conclusions regarding the histomophometric results.
    Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie 02/2011; 65(1):63-8. · 2.24 Impact Factor
  • H.P. Jennissen
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    ABSTRACT: Ultra-hydrophilic titanium surfaces can be prepared in a variety of ways by acid etching. However such surfaces are unstable in air and in water so that a storage for several years, as is necessary for clinical use, is a major problem. Ultrahydrophilic surfaces on miniplates prepared by chromosulfuric acid (CSA) enhancement showing dynamic advancing and receding contact angles of 0° (no hysteresis) can be easily stabilized and stored at room temperature in the dry state in air atmosphere. After evaporation of the aqueous phase of a salt containing solution (e. g. PBS) an exsiccation layer composed of specific ions is formed on the dry metal oxide surface exerting the stabilizing effect. The mechanism involved in this stabilizing effect of salts appears to be governed by the Hofmeister Effect. Ultra-hydrophilic CSA (chromsulfuric acid) etched surfaces can be stabilized by an exsiccation layer for over 3 years without loss of hydrophilicity.Ultra-hydrophile Titanoberflächen können auf verschiedenen Wegen gewonnen werden. Diese Oberflächen verlieren jedoch sowohl in der Luft als auch in Wasser ihre ultra-hydrophilen Eigenschaften, wodurch die Lagerung über mehrere Jahre, wie sie für Implantate notwendig ist, zum Problem wird. Ultrahydrophile Oberflächen auf Titanplättchen, die mit Chromschwefelsäure (CSA) veredelt wurden und dynamische Vorrück- und Rückzugswinkel von 0 Grad (keine Hysterese) aufweisen, können leicht im trockenen Zustand bei Zimmertemperatur in Luftatmosphäre stabilisiert und gelagert werden. Nach Evaporierung der wässrigen Phase einer Salzlösung (z. B. PBS) bildet sich auf der Metalloberfläche eine Exsikkationsschicht bestehend aus einer spezifischen Ionenzusammensetzung, die den stabilisierenden Effekt hervorruft. Der zugrunde liegende Mechanismus für die Stabilisierung von Exsikkationsschichten scheint im Hofmeister-Effekt zu liegen. Ultra-hydrophile CSA (Chromschwefelsäure) geätzte Oberflächen können durch eine Exsikkationsschicht für 3 Jahre stabilisiert und gelagert werden ohne Hydrophilizitätsverlust.
    Materialwissenschaft und Werkstofftechnik 12/2010; 41(12). · 0.51 Impact Factor
  • H.P. Jennissen, S. Lüers
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    ABSTRACT: Titanium alloys are frequently surface-modified by plasma vapor deposition of cp titanium (titanium plasma spraying, TPS; Ti-PVD surface) for clinical use. Such surfaces are extremely rough with Ra values of 30 μm. Unmodified surfaces of Ti-PVD display apparent static contact angles of θS ˜ 145° which are in the ultra-/super-hydrophobic range and in agreement with contact angles of plant leaves displaying the Lotus-Effect. On the same surfaces a static contact angle of θSOil ˜ 0° is found for mineral oil, characterizing the surface as ultra-/superlipophilic in agreement with ultrahydrophobicity (θS/θSOil = 145°/0°). At an inclination angle of 45° droplets of water roll off the Ti-PVD surface with a running rate of ˜20 mm/s. For a classical Lotus-Effect however a roll-off angle of
    Materialwissenschaft und Werkstofftechnik 12/2010; 41(12). · 0.51 Impact Factor
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    ABSTRACT: Recombinant human BMP-2 (rhBMP-2) was immobilized non-covalently and covalently as a monolayer on plasma vapour deposited (PVD) porous commercially pure titanium surfaces in amounts of 5-8 μg cm(-2), providing a ca. 10-fold increase vs. previously reported values. Dissociation of the immobilized [125I]rhBMP-2 from the surface occurred in a two-phase exponential decay: a first rapid phase (ca. 15% of immobilized BMP-2) with a half-life of 1-2 days and a second slow sustained release phase (ca. 85% of immobilized BMP-2) with a half-life of 40-60 days. Dissociation rate constants of sustained release of k(-1)=1.3-1.9 x 10(-7)s(-1) were determined, allowing an estimation of the binding constants (K(A)) for the adsorbed rhBMP-2 monolayer, to be around 10(12) M(-1). The rhBMP-2-coated surfaces showed a high level of biological activity, as demonstrated by in vitro epifluorescence tests for alkaline phosphatase with MC3T3-E1 cells and in vivo experiments. In vivo osteoinductivity of rhBMP-2-coated implants was investigated in a gap-healing model in the trabecular bone of the distal femur condylus of sheep. Healing occurred without inflammation or capsule formation. The calculated concentration of released rhBMP-2 in the 1mm gap ranged from 20 to 98 nM--well above the half-maximal response concentration (K(0.5)) for inducing alkaline phosphatase in MC3T3-E1 cells. After 4, 9 and 12 weeks the bone density (BD) and bone-to-implant contact (BIC) of the explanted implants were assessed histomorphometrically. Implants with immobilized rhBMP-2 displayed a significant (2- to 4-fold) increase in BD and BIC values vs. negative controls after 4-9 weeks. Integration of implants by trabecular bone was achieved after 4 weeks, indicating a mean "gap-filling rate" of ∼250 μm week(-1). Integration of implants by cortical bone was observed after 9 weeks. Control implants without rhBMP-2 were not osseointegrated. This study demonstrates the feasibility of enhancing peri-implant osseointegration and gap bridging by immobilized rhBMP-2 on implant surfaces which may serve as a model for future clinical applications.
    Acta biomaterialia 11/2010; 6(11):4405-21. · 5.68 Impact Factor
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    S U Sixt, H P Jennissen, M Winterhalter, M Laub
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    ABSTRACT: The selective degradation of many proteins in eukaryotic cells is carried out by the ubiquitin system. In this pathway, proteins are targeted for degradation by covalent ligation to ubiquitin, a highly conserved protein [1]. Ubiquitylated proteins were degraded by the 26S proteasome in an ATP-depended manner. The degradation of ubiquitylated proteins were controlled by isopeptidase cleavage. A well characterised system of ubiquitylation and deubiquitylation is the calmodulin system in vitro [2]. Detection of ubiquityl-calmodulin conjugtates in vivo have not been shown so far. In this article we discuss the detection of ubiquitin calmodulin conjugates in vivo by incubation with a novel high-molecular weight ubiquitylprotein-isopeptidase in rabbit tissues. Proteins with a molecular weight of ubiquityl-calmodulin conjugates could be detected in all organs tested. Incubation with ubiquitylprotein-isopeptidase showed clearly a decrease of ubiquitin calmodulin conjugates in vivo with an origination of unbounded ubiquitin. These results suggest that only few ubiquitin calmodulin conjugates exist in rabbit tissues.
    European journal of medical research 10/2010; 15(10):428-47. · 1.10 Impact Factor

Publication Stats

508 Citations
140.46 Total Impact Points

Institutions

  • 2001–2011
    • University of Duisburg-Essen
      Essen, North Rhine-Westphalia, Germany
  • 2010
    • Universitätsklinikum Düsseldorf
      • Klinik für Anästhesiologie
      Düsseldorf, North Rhine-Westphalia, Germany
  • 1995–2005
    • University Hospital Essen
      • Institut für Physiologische Chemie
      Essen, North Rhine-Westphalia, Germany
  • 2000
    • Universität Heidelberg
      • Department of Orthopedics and Traumatology
      Heidelberg, Baden-Wuerttemberg, Germany
  • 1999
    • University of Utah
      • Department of BioEngineering
      Salt Lake City, UT, United States
  • 1993
    • Ruhr-Universität Bochum
      • Institut für Physiologische Chemie
      Bochum, North Rhine-Westphalia, Germany
  • 1985–1989
    • Ludwig-Maximilian-University of Munich
      • Institute of Chinese Studies
      München, Bavaria, Germany
  • 1987
    • University of Tuebingen
      Tübingen, Baden-Württemberg, Germany