Universität zu Köln

Kopp, Alexander ORCID: 0000-0001-8787-0401, Smeets, Ralf, Gosau, Martin, Kroeger, Nadja, Fuest, Sandra, Koepf, Marius, Kruse, Magnus, Krieger, Judith, Rutkowski, Rico, Henningsen, Anders and Burg, Simon (2020). Effect of process parameters on additive-free electrospinning of regenerated silk fibroin nonwovens. Bioact. Mater., 5 (2). S. 241 - 253. BEIJING: KEAI PUBLISHING LTD. ISSN 2452-199X

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Abstract

Silk fibroin is a biomaterial with multiple beneficial properties for use in regenerative medicine and tissue engineering. When dissolving and processing the reconstituted silk fibroin solution by electrospinning, the arrangement and size of fibers can be manifold varied and according fiber diameters reduced to the nanometer range. Such nonwovens show high porosity as well as potential biocompatibility. Usually, electrospinning of most biomaterials demands for the application of additives, which enable stable electrospinning by adjusting viscosity, and are intended to evaporate during processing or to be washed out afterwards. However, the use of such additives increases costs and has to be taken into account in terms of biological risks when used for biomedical applications. In this study, we explored the possibilities of additive-free electrospinning of pure fibroin nonwovens and tried to optimize process parameters to enable stable processing. We used natural silk derived from the mulberry silkworm Bombyx mori. After degumming, the silk fibroin was dissolved and the viscosity of the spinning solution was controlled by partial evaporation of the initial solving agent. This way, we were able to completely avoid the use of additives and manufacture nonwovens, which potentially offer higher biocompatibility and reduced immunogenicity. Temperature and relative humidity during electrospinning were systematically varied (25-35 degrees C, 25-30% RH). In a second step, the nonwovens optionally underwent methanol treatment to initiate beta-sheet formation in order to increase structural integrity and strength. Comprehensive surface analysis on the different nonwovens was performed using scanning electron microscopy and supplemented by additional mechanical testing. Cytotoxicity was evaluated using BrdU-assay, XTT-assay, LDH-assay and live-dead staining. Our findings were, that an increase of temperature and relative humidity led to unequal fiber diameters and defective nonwovens. Resistance to penetration decreased accordingly. The most uniform fiber diameters of 998 +/- 63 nm were obtained at 30 degrees C and 25% relative humidity, also showing the highest value for resistance to penetration (0.20 N). The according pure fibroin nonwoven also showed no signs of cytotoxicity. However, while the biological response showed statistical evidence, the material characteristics showed no statistically significant correlation to changes of the ambient conditions within the investigated ranges. We suggest that further experiments should explore additional ranges for temperature and humidity and further focus on the repeatability of material properties in dependency of suitable process windows.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Kopp, Alexander UNSPECIFIED orcid.org/0000-0001-8787-0401 UNSPECIFIED Smeets, Ralf UNSPECIFIED UNSPECIFIED UNSPECIFIED Gosau, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Kroeger, Nadja UNSPECIFIED UNSPECIFIED UNSPECIFIED Fuest, Sandra UNSPECIFIED UNSPECIFIED UNSPECIFIED Koepf, Marius UNSPECIFIED UNSPECIFIED UNSPECIFIED Kruse, Magnus UNSPECIFIED UNSPECIFIED UNSPECIFIED Krieger, Judith UNSPECIFIED UNSPECIFIED UNSPECIFIED Rutkowski, Rico UNSPECIFIED UNSPECIFIED UNSPECIFIED Henningsen, Anders UNSPECIFIED UNSPECIFIED UNSPECIFIED Burg, Simon UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-332324
DOI:	10.1016/j.bioactmat.2020.01.010
Journal or Publication Title:	Bioact. Mater.
Volume:	5
Number:	2
Page Range:	S. 241 - 253
Date:	2020
Publisher:	KEAI PUBLISHING LTD
Place of Publication:	BEIJING
ISSN:	2452-199X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language IN-VIVO DEGRADATION; SCAFFOLD; SERICIN; NANOFIBERS Multiple languages Engineering, Biomedical; Materials Science, Biomaterials Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33232