Engineering Extracellular Matrix Mimetic Hyaluronic Acid Hydrogels for Evaluating Cellular Behavior
Kemppi, Hanna (2018)
2018
Biotekniikka
Teknis-luonnontieteellinen tiedekunta - Faculty of Natural Sciences
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Hyväksymispäivämäärä
2018-12-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201811142576
https://urn.fi/URN:NBN:fi:tty-201811142576
Tiivistelmä
3D (three-dimensional) scaffolds designed by using the extracellular matrix (ECM) polymers, mimics the natural tissue and assist in studying the natural cellular processes. Hyaluronic acid (HA) is one such ECM component which is broadly used for fabricating 3D tissue engineering scaffolds. HA polymer has several reactive sites which can be chemically modified with different functional moieties. This makes it possible to design materials for various biomedical applications. In this study, we have developed two types of 3D scaffolds: gold nanoparticle (AuNP) doped conductive scaffold for culturing cardiac cells and another hydrazone crosslinked hydrogel to evaluate the cell differentiation potential under acidic and neutral environments. The aim of this study was to evaluate the effect of the different 3D scaffolds on the cell behavior.
In the first part, the suitability of the conductive gold nanoparticle hydrogels for cardiac application was evaluated. AuNPs were synthesized by using two different methods. In 3,3’-dithiobis(propanoic hydrazide) (DTPH) hydrogels nanoparticles were formed in situ, while in carbodihydrazide (CDH) hydrogels HA-conjugated gold nanoparticles (HA-AuNP) were added to the hydrogel solution. Biocompatibility of the hydrogels was tested by culturing human induced pluripotent stem cell (iPSC) derived cardiomyocytes on the hydrogels and their beating was video recorded.
The in situ formed gold nanoparticles increased stability of the DTPH hydrogels by forming an interpenetrating network, while HA-AuNPs did not affect the stability of the CDH hydrogels. Both gold nanoparticle hydrogels seemed to be suitable for the cardiac applications since cardiomyocytes were able to beat on the surface of the hydrogels. Due to problems with the supply of the cardiomyocytes, only the preliminary cell test was done. Further cell studies and the evaluation of the conductivity should proceeded.
In the second part, the effect of the extracellular pH on cell differentiation in 3D scaffold was evaluated. A temporary drop in the extracellular pH can occur during the healing process. To study stem cell viability and differentiation in the acidic conditions, human bone marrow mesenchymal stem cells (bMSC) were cultured in the acidic and the neutral HA hydrogels. Tests were repeated with mouse osteoblast precursor cells (MC3T3).
Cell viability was higher in neutral hydrogels than in acidic, but acidic hydrogels were able to enhance osteogenic differentiation of the bMSC and MC-3T3 without any differentiation compounds compared with neutral hydrogels and cell controls. The gene expression studied should be done to evaluate the expression of later osteogenic markers.
In the first part, the suitability of the conductive gold nanoparticle hydrogels for cardiac application was evaluated. AuNPs were synthesized by using two different methods. In 3,3’-dithiobis(propanoic hydrazide) (DTPH) hydrogels nanoparticles were formed in situ, while in carbodihydrazide (CDH) hydrogels HA-conjugated gold nanoparticles (HA-AuNP) were added to the hydrogel solution. Biocompatibility of the hydrogels was tested by culturing human induced pluripotent stem cell (iPSC) derived cardiomyocytes on the hydrogels and their beating was video recorded.
The in situ formed gold nanoparticles increased stability of the DTPH hydrogels by forming an interpenetrating network, while HA-AuNPs did not affect the stability of the CDH hydrogels. Both gold nanoparticle hydrogels seemed to be suitable for the cardiac applications since cardiomyocytes were able to beat on the surface of the hydrogels. Due to problems with the supply of the cardiomyocytes, only the preliminary cell test was done. Further cell studies and the evaluation of the conductivity should proceeded.
In the second part, the effect of the extracellular pH on cell differentiation in 3D scaffold was evaluated. A temporary drop in the extracellular pH can occur during the healing process. To study stem cell viability and differentiation in the acidic conditions, human bone marrow mesenchymal stem cells (bMSC) were cultured in the acidic and the neutral HA hydrogels. Tests were repeated with mouse osteoblast precursor cells (MC3T3).
Cell viability was higher in neutral hydrogels than in acidic, but acidic hydrogels were able to enhance osteogenic differentiation of the bMSC and MC-3T3 without any differentiation compounds compared with neutral hydrogels and cell controls. The gene expression studied should be done to evaluate the expression of later osteogenic markers.