Pietzsch, M. | Search bioRxiv

bioRxiv2022

Free-Standing Multilayer Films as Growth Factor Reservoirs for Future Wound Dressing Applications

Chronic skin wounds place a high burden on patients and health care systems. The use of angiogenic and mitogenic growth factors (GF) can facilitate the healing but GF are quickly inactivated by the wound environment if added exogenously. Here, free-standing multilayer films (FSF) are fabricated from chitosan (CHI) and alginate (ALG) as opposing polyelectrolytes in an alternating manner using layer-by-layer technique (LbL). One hundred bilayers form an about 450 {micro}m thick, detachable free-standing film (N-FSF) that is subsequently crosslinked by either ethyl (dimethylaminopropyl) carbodiimide (EDC) combined with N-hydroxysuccinimide (NHS) (E-FSF) or genipin (G-FSF). The characterization of swelling, oxygen permeability and crosslinking density shows reduced swelling and oxygen permeability for both crosslinked films compared to N-FSF. Loading of fibroblast growth factor 2 (FGF2) into the films results in a sustained release of GF from crosslinked in comparison to N-FSF. Biocompatibility studies in vitro with human dermal fibroblasts (HDF) cultured underneath the films demonstrate increased cell growth and cell migration for all films with and without FGF2. Especially G-FSF loaded with FGF2 greatly increases cell proliferation and migration. In vivo biocompatibility studies by subcutaneous implantation in mice show that E-FSF causes a strong inflammatory response while G-FSF is of high biocompatibility. N-FSF also represents a biocompatible film but shows early degradation. All FSF possess antibacterial properties against gram+ and gram-bacteria demonstrated by an agar diffusion disc assay. In summary, FSF made of ALG and CHI crosslinked with genipin can act as a reservoir for the sustained release of FGF2, possessing high biocompatibility in vitro and in vivo. Moreover, G-FSF promotes growth and migration of HDF and has antibacterial properties which makes it an interesting candidate for bioactive wound dressings.

bioengineering↗

bioRxiv2021

Patient-derived endometrial organoids from MRKH patients: Insight in disease causing pathways

The uterus is responsible for the nourishment and mechanical protection of the developing embryo and fetus and is an essential part in mammalian reproduction. The Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is characterized by agenesis of the uterus and upper part of the vagina in females with normal ovarian function. Although heavily studied, the cause of the disease is still enigmatic. Current research in the field of MRKH mainly focusses on DNA-sequencing efforts and, so far, failed to decipher the nature and heterogeneity of the disease, thereby holding back scientific and clinical progress. Here, we developed long-term expandable organoid cultures from endometrium found in uterine rudiment horns of MRKH patients. Phenotypically, they share great similarity with healthy control organoids and are surprisingly fully hormone responsive. Transcriptome analyses, however, identified an array of dysregulated genes that point at potentially disease-causing pathways altered during the development of the female reproductive tract. We consider the endometrial organoid cultures to be a powerful research tool that promise to enable an array of studies into the pathogenic origins of MRKH syndrome and possible treatment opportunities to improve patient quality of life.

developmental biology↗