Please login first
Qun Ren   Dr.  Institute, Department or Faculty Head 
Timeline See timeline
Qun Ren published an article in February 2019.
Top co-authors See all
Francesco Stellacci

208 shared publications

École Polytechnique Fédérale de Lausanne

Jürgen Brugger

121 shared publications

Microsystems Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

Katharina Maniura-Weber

73 shared publications

Laboratory for Biointerfaces; Empa, Swiss Federal Laboratories for Materials Science & Technology; Lerchenfeldstrasse 5 9014 St. Gallen Switzerland

Patrick Rupper

52 shared publications

Laboratory for Advanced Fibers, Empa, Lerchenfeldstrase 5, St. Gallen 9014, Switzerland

Bernard Witholt

47 shared publications

Institute of Molecular Systems Biology, Swiss Federal Institute of Technology, CH-8093 Zurich, Switzerland

Publication Record
Distribution of Articles published per year 
(2000 - 2019)
Total number of journals
published in
Publications See all
Article 0 Reads 0 Citations Bacterial Adhesion on Soft Materials: Passive Physicochemical Interactions or Active Bacterial Mechanosensing? Hervé Straub, Claudio M. Bigger, Jules Valentin, Dominik Abt... Published: 18 February 2019
Advanced Healthcare Materials, doi: 10.1002/adhm.201801323
DOI See at publisher website
Article 0 Reads 0 Citations From Structure to Function: pH-Switchable Antimicrobial Nano-Self-Assemblies Mark Gontsarik, Anan Yaghmur, Qun Ren, Katharina Maniura-Web... Published: 27 December 2018
ACS Applied Materials & Interfaces, doi: 10.1021/acsami.8b18618
DOI See at publisher website
Article 0 Reads 0 Citations Influence of biofilms on morbidity associated with short-term indwelling ureteral stents: a prospective observational st... Patrick Betschart, Valentin Zumstein, Matthias T. Buhmann, W... Published: 27 November 2018
World Journal of Urology, doi: 10.1007/s00345-018-2569-z
DOI See at publisher website
Article 0 Reads 1 Citation Extraction of Biofilms From Ureteral Stents for Quantification and Cultivation-Dependent and -Independent Analyses Matthias T. Buhmann, Dominik Abt, Stefanie Altenried, Patric... Published: 10 July 2018
Frontiers in Cellular and Infection Microbiology, doi: 10.3389/fmicb.2018.01470
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Ureteral stenting is a common surgical procedure, which is associated with a high morbidity and economic burden, but the knowledge on the link between biofilms on these stents, morbidity, and the impact of the involved microbiota is still limited. This is partially due to a lack of methods that allow for a controlled extraction of the biofilms from stents. Development of an appropriate in vitro model to assess prevention of biofilm formation by antimicrobial coatings and biomaterials requires a profound understanding of the biofilm composition, including the involved microbiota. This work describes an analytical pipeline for the extraction of native biofilms from ureteral stents for both cultivation-dependent and -independent analysis, involving a novel mechanical abrasion method of passing stent samples through a tapered pinhole. The efficiency of this novel method was evaluated by quantifying the removed biofilm mass, numbers of cultivable bacteria, calcium content, and microscopic stent analysis after biofilm removal using 30 clinical stent samples. Furthermore, the extraction of in vitro formed Escherichia coli biofilms was evaluated by universal 16S quantitative PCR, a cultivation-independent method to demonstrate efficient biofilm removal by the new approach. The novel method enables effective contamination-free extraction of the biofilms formed on ureteral stents and their subsequent quantification, and it represents a useful tool for comprehensive examinations of biofilms on ureteral stents.
Article 0 Reads 1 Citation Role of the Surface Nanoscale Roughness of Stainless Steel on Bacterial Adhesion and Microcolony Formation Songmei Wu, Stefanie Altenried, Andi Zogg, Flavia Zuber, Kat... Published: 15 June 2018
ACS Omega, doi: 10.1021/acsomega.8b00769
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Hospital-acquired infections can cause serious complications and are a severe problem because of the increased emergence of antibiotic-resistant bacteria. Biophysical modification of the material surfaces to prevent or reduce bacteria adhesion is an attractive alternative to antibiotic treatment. Since stainless steel is a widely used material for implants and in hospital settings, in this work, we used stainless steel to investigate the effect of the material surface topographies on bacterial adhesion and early biofilm formation. Stainless steel samples with different surface roughnesses Rq in a range of 217.9–56.6 nm (Ra in a range of 172.5–45.2 nm) were fabricated via electropolishing and compared for adhesion of bacterial pathogens Pseudomonas aeruginosa and Staphylococcus aureus. It was found that the number of viable cells on the untreated rough surface was at least 10-fold lower than those on the electropolished surfaces after 4 h of incubation time for P. aeruginosa and 15-fold lower for S. aureus. Fluorescence images and scanning electron microscopy images revealed that the bacterial cells tend to adhere individually as single cells on untreated rough surfaces. In contrast, clusters of the bacterial cells (microcolonies) were observed on electropolished smooth surfaces. Our study demonstrates that nanoscale surface roughness can play an important role in restraining bacterial adhesion and formation of microcolonies.
Article 0 Reads 1 Citation Nanostructured surface topographies have an effect on bactericidal activity Songmei Wu, Flavia Zuber, Katharina Maniura-Weber, Juergen B... Published: 28 February 2018
Journal of Nanobiotechnology, doi: 10.1186/s12951-018-0347-0
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
Due to the increased emergence of antimicrobial resistance, alternatives to minimize the usage of antibiotics become attractive solutions. Biophysical manipulation of material surface topography to prevent bacterial adhesion is one promising approach. To this end, it is essential to understand the relationship between surface topographical features and bactericidal properties in order to develop antibacterial surfaces. In this work a systematic study of topographical effects on bactericidal activity of nanostructured surfaces is presented. Nanostructured Ormostamp polymer surfaces are fabricated by nano-replication technology using nanoporous templates resulting in 80-nm diameter nanopillars. Six Ormostamp surfaces with nanopillar arrays of various nanopillar densities and heights are obtained by modifying the nanoporous template. The surface roughness ranges from 3.1 to 39.1 nm for the different pillar area parameters. A Gram-positive bacterium, Staphylococcus aureus, is used as the model bacterial strain. An average pillar density at ~ 40 pillars μm−2 with surface roughness of 39.1 nm possesses the highest bactericidal efficiency being close to 100% compared with 20% of the flat control samples. High density structures at ~ 70 pillars μm−2 and low density structures at < 20 pillars μm−2 with surface roughness smaller than 20 nm reduce the bactericidal efficiency to almost the level of the control samples. The results obtained here suggests that the topographical effects including pillar density and pillar height inhomogeneity may have significant impacts on adhering pattern and stretching degree of bacterial cell membrane. A biophysical model is prepared to interpret the morphological changes of bacteria on these nanostructures. The online version of this article (10.1186/s12951-018-0347-0) contains supplementary material, which is available to authorized users.