| During the past decades, our knowledge about hydrogels has expanded for theirexcellent elasticity, moisture content and biocompatibility. Synthetic hydrogels havestable structure and mechanical properties by controlling the crosslinking process, whilenatural hydrogels show excellent biocompatibility and special functional. To make upfor deficiencies of a single synthetic hydrogels or natural hydrogels performance, thecomposite hydrogels materials with good mechanical properties and functionalbiological properties were prepared by combining synthetic hydrogels with naturalhydrogels. Therefore, the scope of application of hydrogels materials was expanded andthe performance of the hydrogels was improved.The biological behaviors could be affected by the changes of the extracellularmicroenvironment, and the mechanical response of cells play an important role in thisprocess. For the cells which were anchorage, the biological behaviors of cells altered byown regulating when cells induced basal hardness changes, such as the change of cellsmorphology and migration orientation of cells or the change of the proliferation anddifferentiation, etc. Therefore, the changes in extracellular mechanicalmicroenvironment would have a huge impact on organizational development, even thewhole living organisms. Besides, it is particularly necessary that the mechanicalproperties of anchorage basal were researched.In this paper, polyvinyl alcohol/calcium alginate (PVA/SA-Ca) compositehydrogels were prepared by freezing-thawing of method crosslinking polyvinyl alcoholfirstly and ionic crosslinking sodium alginate with Ca2+further. Some factors whichaffected mechanical properties and swelling performance of mixed hydrogels wereexamined, such as the number of freeze-thaw cycles, the hydrogel proportion and theconcentration of calcium chloride solution. For PVA/SA-Ca hydrogels of theconcentration of1%PVA and2.5%sodium alginate, polyvinyl alcohol crosslinkcompletely when the number of freezing-thawing cycles was6. Ionic crosslinkingreaction was finished after PVA/SA hydrogels were immersed in Ca2+solution about4h.Along with the increase of Ca2+concentration, equilibrium water content (EWC) ofhydrogels decreased. Elasticity modulus of hydrogels increased with the increase ofCa2+concentration when the content of sodium alginate (SA) was small, and when thecontent of sodium alginate (SA) was larger and the concentration of Ca2+was 0.075mol/L, elasticity modulus of PVA/SA-Ca hydrogels reached a maximum. Then,the relationship between equilibrium water content (EWC) and the content of sodiumalginate (w), the calcium ion concentration (c) was studied. Meanwhile, it was discussedthat how the content of sodium alginate (w) and the calcium ion concentration (c)influence elasticity modulus (E). The mathematical models of EWC, E of compositehydrogels were established separately through the regression analysis. In addition, thisstudy adopted the improved stretching method to measure the elasticity modulus ofcompound hydrogels. The stretching method can reduce the error which was caused byown gravity of hydrogels producing great deformation, at the same time, the operationwas simple and measurement results were more accurate. These advantages would lay asolid foundation for accurate mathematical simulation. The mechanical propertiessimulation of poly (vinyl alcohol)/calcium alginate hydrogels and quantitative controlcan be achieved.The poly (vinyl alcohol)/calcium alginate composite hydrogels were used in livercells culture. Cells’ mechanical response behavior in the basal was studied. Thecomposite hydrogels were used to simulate liver tissue of fibrosis pathological changes,whose elastic modulus value was3.6kPa,10kPa and30kPa, respectively.Morphological changes of L02cells in different hardness basal were studied, etc.Parameters of cells on different hardness basal with Image J software were tested, suchas spreading area and perimeter index. The evidences showed that cells roundness value(CF) was close to1and the cells appeared a round shape in the soft base, while cellspreading area was larger and became into a polygon in a hard substrate. With theincrease of basal hardness, this phenomenon was more obvious. |
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