Influnce of Calcium and Alginate Concentration on Human Chondrocyte Survival

The calcium alginate matrix, which has been used as a delivery vehicle for autogenous transplantation of the human chondrocytes, should provide a suitable environment for chondrocyte survival and for generation of new cartilage-like tissue. To optimize calcium alginate condition for human chondrocytes, the viscosity and concentration of sodium alginate and the CaCl2 concentration were varied during manufacture of the alginate discs. Human rib cartilage was dissected, enzymatically dissociated, and the chondrocytes were collected by centrifugation. Chondrocyte viability measured after fourteen days of culture by quantification of the DNA content per alginate discs. Sodium alginate concentrations were tested at four different levels varying from 0.5% to 3 percent using both low and moderate viscosity alginates. The DNA content was highest at 0.5% percent and lowest at 3 percent with both alginates. Varying the CaCl2 concentrations for polymerization from 50 to 200 mM produced no difference in DNA content. These data demonstrate that sodium alginate concentration rather than CaCl2 concentration is a critical factor for successful encapsulation of human cartilage cells in a calcium alginate matrix.

Human Chondrocyte Viability against Time and Density in Calcium Alginate In Vitro

One Approach for caraniofacial contouring surgery is to use autogenous cartilage cells localized within a biocompatible polymer. This study investigated varying conditions of polymerization at cell density on the viability of human chondrocytes encapsulated in calcium alginate. Human rib cartilage was dissected, enzymatically dissociated, and the chondrocytes were collected by centrifugation. Alginate discs containig chondrocyte were made from 1.5% sodium alginate and 100 mM CaCI solution. Viability of chondrocytes was measured by quantification of the DNA content per alginate discs at six different time intervals from 0 to 5 weeeks. Significant initial cell loss was observed in the first two weeks after which the survival rate remained stationary. To optimize calcium alginate matrix formation with human chondrocytes, the cell density was varied during manufacture of the alginate discs. Chondrocyte viability was measured after fourteen days of culture as same method mentioned above. Varying the cell density at the time of polymerization from 2.0x10 to 2.0x10' chondrocytes/ml produced a direct relationship between number of cells and chondrocyte viability. The greatest viability(70.2 percent) was observed with cell density of 2.0 x 10' chondrocytes/ml. These data demonstrate that cell density is a critical factor for successful encapsulation of human cartilage cells in a calcium alginate matrix.