Janus 3D Printed Dynamic Scaffolds for Nanovibration-Driven Bone Regeneration

The application of physical stimuli to cell cultures has shown potential to modulate multiple cellular functions including migration, differentiation and survival. However, the relevance of these invitro models to future potential extrapolation invivo depends on whether stimuli can be applied "externally", without invasive procedures. Here, we report on the fabrication and exploitation of dynamic additive-manufactured Janus scaffolds that are activated on-command via external application of ultrasounds, resulting in a mechanical nanovibration that is transmitted to the surrounding cells. Janus scaffolds were spontaneously formed via phase-segregation of biodegradable polycaprolactone (PCL) and polylactide (PLA) blends during the manufacturing process and behave as ultrasound transducers (acoustic to mechanical) where the PLA and PCL phases represent the active and backing materials, respectively. Remote stimulation of Janus scaffolds led to enhanced cell proliferation, matrix deposition and osteogenic differentiation of seeded human bone marrow derived stromal cells (hBMSCs) via formation and activation of voltage-gated calcium ion channelsThe authors acknowledge the Texas A&M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White who isolated and provided the cells through a grant from NCRR of the NIH (Grant #P40RR017447). The authors acknowledge the financial support from the European Commission under the ERC starting grant “Cell Hybridge” of the Horizon2020 framework program (Grant # 637308)

Konstruktive Fallbesprechungen im Mentoring: Erfahrungen aus einem Versuch im Rahmen der berufspraktischen Ausbildung

This article describes an attempt to optimize teacher mentoring during pre-service training at schools through constructive casework. Initially the requirements and characteristics of constructive casework are discussed. Then the theoretical foundations for the key elements are developed. In addition, the systematic contribution of casework to competency development, and the implications for cooperation in mentoring are addressed. One focus is on the conditions of the experiment, whereby sequences of conversation protocols with a student are analyzed. The example shows that constructive casework can make an important contribution to competency development, which generalizes beyond the specific requirements of the particular situation.Der Beitrag gibt Einblick in einen Versuch, Mentoring im Praktikum durch konstruktive Fallarbeit zu optimieren. Zu Beginn werden Erfordernisse und Charakteristika konstruktiver Fallarbeit behandelt. Anschliessend werden die Eckpunkte des Versuchs theoretisch untermauert. Erläutert wird, was unter konstruktiver Fallarbeit verstanden wird. Im Weiteren werden ihr Beitrag zum systematischen Kompetenzaufbau und ihre Konsequenzen für die Kooperation im Mentoring angesprochen. Einen Schwerpunkt bilden die Rahmenbedingungen des durchgeführten Versuchs, der anhand von Sequenzen aus Gesprächsprotokollen mit einer Studentin konkretisiert wird. Das Beispiel zeigt, dass konstruktive Fallarbeit im Praktikum einen wichtigen Beitrag zum Kompetenzaufbau leisten kann, der über die Bewältigung der spezifischen Situation hinausgeht

Verbindung von Theorie und Praxis bei der Begleitung von Praxisphasen in der Lehrerbildung

Mentoring with clear reference to the linkage between theory and practice means that actions between the university and practice are being coordinated. Common efforts are needed at the structural, the communicative and at the level of the learning processes. One strives for an improved linkage between theory and practice. Using the development of the skill of inner differentiation as an example, the study examined effects of coordinative activities in mentoring on (a) substantive relations between theory and practice, and (b) on the assessed skills at the beginning, during and at the end of the learning process. The qualitative interview data was collected from 25 students in the fifth (of six) semesters of their training as a primary school teacher. In the quantitative analysis data from 34 students were used. Conversation analysis showed that the topics, which have been developed during the course at the university did coin the discussions in the lesson meetings. Furthermore, during the course of the learning process the students estimated their skills increasingly higher, but the importance of the skills in question remained constant. The subjective assessments at the beginning and at the end of the learning process correlated statistically significantly with the external assessment of a final written reflection paper.Mentoring mit deutlichem Bezug zur Verbindung von Theorie und Praxis verlangt, dass Massnahmen zwischen Hochschule und Praxisfeld aufeinander abgestimmt werden. Gemeinsame Anstrengungen sind notwendig auf struktureller, kommunikativer und auf der Ebene der Lernprozesse. Dabei erhofft man sich eine engere Verknüpfung zwischen Theorie und Praxis. Am Beispiel der Kompetenzentwicklung zur Inneren Differenzierung untersucht die Studie Effekte koordinativer Massnahamen im Mentoring (a) auf inhaltliche Relationen zwischen Lehre und Praxis sowie (b) auf die eingeschätzten Kompetenzen zu Beginn, während und am Ende des Lernprozesses. Die qualitativen Gesprächsdaten stammen von 25 Studierenden im fünften Semester ihrer sechssemestrigen Ausbildung zur Grundschullehrkraft. In die quantitative Analyse gingen Daten von 34 Studierenden ein. Gesprächsanalysen zeigten, dass die Themen, die im Kurs an der Hochschule erarbeitet worden waren, auch die Unterrichtsbesprechungen prägten. Ferner schätzten die Studierenden ihr Können, jedoch nicht die Wichtigkeit der fraglichen Kompetenzen im Verlauf des Lernprozesses zunehmend höher ein. Ihre subjektiven Einschätzungen zu Beginn und am Ende des Lernprozesses korrelierten im Weiteren statistisch signifikant mit der Fremdbeurteilung einer abschliessenden schriftlichen Reflexionsarbeit

Herausforderung Differenzierung: Eine Studie zur Entwicklung anspruchsvoller Handlungskompetenzen von Lehramtsstudierenden im Spannungsfeld zwischen theoretischer und praktischer Ausbildung

Using the development of the sophisticated competencies of inner differentiation as an example, the study examined how connections between theory and practice in classrooms can be established. Cooperative settings between the Teacher Training College and classroom practice were implemented, such as the participation of experienced teachers in the preparation course, workshops with mentor teachers, and creating a lecturer team in order to link theory and practical training. Based on the Cognitive Flexibility Theory of Spiro et al. (1991), we conceived a situated learning environment. This allowed reviewing the planning and implementation of classroom instruction from multiple perspectives. In total, conversations of 75 coaching sessions were analyzed. Student teachers (N = 25) had a theory-based preparative coaching session with a lecturer at the Teacher Training College, a preparative coaching session at school with the mentor teacher, and a debriefing coaching session with both, the lecturer and the mentor teacher. Findings showed that elements of theory did indeed emerge during the coaching sessions. The content of discussion varied according to the setting; issues were initiated in the majority of cases by the student teachers. Moreover student teachers perceived their competencies increasingly positive over the course of the training sequence.Am Beispiel der Entwicklung anspruchsvoller Kompetenzen zur inneren Differenzierung wird untersucht, wie sich Beziehungen zwischen der theoretischen Ausbildung und schulpraktischen Erfahrungen herstellen lassen. Implementiert wurden kooperative Strukturen zwischen Hochschule und Praxis wie der Einbezug eines Praxisdozenten in die Lehre, Workshops mit Praxislehrkräften und die Bildung eines Teams von Dozierenden zur Herstellung von Verbindungen zwischen Lehre und Praktikum. Darauf aufbauend wurde in Anlehnung an die Theorie der kognitiven Flexibilität von Spiro et al. (1991) eine fallbasierte Lernumgebung konzipiert. Diese erlaubte es, die Planung und Durchführung von Unterricht unter multiplen Perspektiven zu besprechen. Analysiert wurden 25 theoriebezogene Vorbesprechungen zwischen Studierenden und einem Dozenten an der Hochschule und 25 Vorbesprechungen mit den Praxislehrkräften. 25 Nachbesprechungen wurden zu dritt durchgeführt. Es zeigte sich, dass Elemente der Lehre Eingang in die Gespräche fanden. Die Inhalte variierten je nach Gesprächssetting, und die Themen wurden mehrheitlich von den Studierenden initiiert. Zudem schätzten die Studierenden ihre Kompetenzen im Laufe der Ausbildungssequenz sukzessive positiver ein

Verknüpfung von Forschungs- und Schreibkompetenz in der Ausbildung von Lehrpersonen - ein Praxisbeispiel

Die Vermittlung von Forschungs- und Schreibkompetenzen ist für die Ausbildung von angehenden Lehrpersonen von zentraler Bedeutung. Im Rahmen der Ausbildung zur Lehrperson auf Sekundarstufe 1 an der Pädagogischen Hochschule Bern (Schweiz) wurde für den Studienbereich "Forschung, Entwicklung und Evaluation" ein Setting geschaffen, welches den simultanen Erwerb von Forschungs- und Schreibkompetenzen beabsichtigt. Der vorliegende Beitrag beschreibt im Sinne eines Good-Practice-Beispiels den Aufbau des Seminars "Forschen, Entwickeln, Evaluieren 1", in welchem die Verknüpfung von Forschungs- und Schreibkompetenzen besonders zum Tragen kommt. 09.05.2016 | Gisela Bürki & Sandra Moroni (Bern

Additive manufacturing of an elastic poly(ester)urethane for cartilage tissue engineering

Although a growing knowledge on the field of tissue engineering of articular cartilage exists, reconstruction or in-vitro growth of functional hyaline tissue still represents an unmet challenge. Despite the simplicity of the tissue in terms of cell population and absence of innervation and vascularization, the outstanding mechanical properties of articular cartilage, which are the result of the specificity of its extra cellular matrix (ECM), are difficult to mimic. Most importantly, controlling the differentiation state or phenotype of chondrocytes, which are responsible of the deposition of this specialized ECM. represents a milestone in the regeneration of native articular cartilage. In this study, we fabricated fused deposition modelled (FDM) scaffolds with different pore sizes and architectures from an elastic and biodegradable poly(ester)urethane (PEU) with mechanical properties that can be modulated by design, and that ranged the elasticity of articular cartilage. Cell culture in additive manufactured 3D scaffolds exceeded the chondrogenic potential of the gold-standard pellet culture. In-vitro cell culture studies demonstrated the intrinsic potential of elastic (PEU) to drive the re-differentiation of de-differentiated chondrocytes when cultured in-vitro, in differentiation or basal media, better than pellet cultures. The formation of neo-tissue was assessed as a high deposition of GAGs and fibrillar collagen II, and a high expression of typical chondrogenic markers. Moreover, the collagen II / collagen I ratio commonly used to evaluate the differentiation state of chondrocytes (ratio > 1 being chondrocytes and, ratio <0 being de-differentiated chondrocytes) was higher than 5. Statement of significance Tissue engineering of articular cartilage requires material scaffolds capable of driving the deposition of a coherent and specific ECM representative of articular cartilage. Materials explored so far account for low mechanical properties (hydrogels), or are too stiff to mimic the elasticity of the native tissue (traditional polyesters). Here, we fabricated 3D fibrous scaffolds via FDM with a biodegradable poly(ester)urethane. The compressive Young's modulus and elastic limit of the scaffolds can be tuned by designed, mimicking those of the native tissue. The designed scaffolds showed an intrinsic potential to drive the formation of a GAG and collagen II rich ECM, and to drive a stable chondrogenic cell phenotype. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Bioprinting:From Tissue and Organ Development to <i>in Vitro</i> Models

Bioprinting techniques have been flourishing in the field of biofabrication with pronounced and exponential developments in the past years. Novel biomaterial inks used for the formation of bioinks have been developed, allowing the manufacturing of in vitro models and implants tested preclinically with a certain degree of success. Furthermore, incredible advances in cell biology, namely, in pluripotent stem cells, have also contributed to the latest milestones where more relevant tissues or organ-like constructs with a certain degree of functionality can already be obtained. These incredible strides have been possible with a multitude of multidisciplinary teams around the world, working to make bioprinted tissues and organs more relevant and functional. Yet, there is still a long way to go until these biofabricated constructs will be able to reach the clinics. In this review, we summarize the main bioprinting activities linking them to tissue and organ development and physiology. Most bioprinting approaches focus on mimicking fully matured tissues. Future bioprinting strategies might pursue earlier developmental stages of tissues and organs. The continuous convergence of the experts in the fields of material sciences, cell biology, engineering, and many other disciplines will gradually allow us to overcome the barriers identified on the demanding path toward manufacturing and adoption of tissue and organ replacements.</p

Mechanosensitive regulation of stanniocalcin-1 by zyxin and actin-myosin in human mesenchymal stromal cells

Stanniocalcin-1 (STC1) secreted by mesenchymal stromal cells (MSCs) has anti-inflammatory functions, reduces apoptosis, and aids in angiogenesis, both in vitro and in vivo. However, little is known about the molecular mechanisms of its regulation. Here, we show that STC1 secretion is increased only under specific cell-stress conditions. We find that this is due to a change in actin stress fibers and actin-myosin tension. Abolishment of stress fibers by blebbistatin and knockdown of the focal adhesion protein zyxin leads to an increase in STC1 secretion. To also study this connection in 3D, where few focal adhesions and actin stress fibers are present, STC1 expression was analyzed in 3D alginate hydrogels and 3D electrospun scaffolds. Indeed, STC1 secretion was increased in these low cellular tension 3D environments. Together, our data show that STC1 does not directly respond to cell stress, but that it is regulated through mechanotransduction. This research takes a step forward in the fundamental understanding of STC1 regulation and can have implications for cell-based regenerative medicine, where cell survival, anti-inflammatory factors and angiogenesis are critical