In this study, we, for the first time, tried to apply IC50 values (inhibitory concentration estimated to affect the endpoint in question by 50%) in the MTT colorimetric assay to investigate the cytotoxic effects of highly absorbent foam dressings based on silver zirconium phosphate, a newly nano-based matrix. Our results showed that silver released from dressings based on silver zirconium phosphate attributed mainly to highly cytotoxic to L929 cells cultured with MEM containing 10% fetal bovine serum. In addition, we have also compared the IC50 values among different dilutions of AgNO3 solution, silver based dressing extracts and material reference control (ZDEC) extracts using the optimized MTT assay, along with characterizing the silver content in the dressing extracts using atomic absorption spectroscopy. Results have shown that the IC50 values of AgNO50 solution, silver based dressing extracts and ZDEC extracts are 3.5 μg/mL, 3.8 μg/mL and 8.4%, respectively. And there exist some good agreements between qualitative and quantitative evaluation method as well. In conclusion, our study has led to the view that the IC50 value is a promising quantitative index for screening cytotoxicity with regard to silver based dressings.
With ever-increasing operating frequencies and
complicated artificial structures, loss effects become more and more important
in applications of metamaterials. Based on circuit theory and transmission line
principle, the design equations for effective electromagnetic (EM) parameters
(attenuation constant α, phase constant β, characteristic impedance Z0) of general active and passive
metamaterial are compared and derived from the equivalent lumped circuit
parameters (R, G, LL, CL, LR, CR).
To verify the design equations, theα, βand Z0 indifferent cases, including balanced, unbalanced, lossless, passive and active,
are shown by numerical simulations. The results show that using the active
method can diminish the loss effects. Meantime, it also has influence on phase constant
and real part of characteristic impedance.