CHONDROITIN-6-SULFATE INCORPORATED INTO COLLAGEN GELS FOR THE GROWTH OF HUMAN KERATINOCYTES - THE EFFECT OF CROSS-LINKING AGENTS AND DIAMINES

This study demonstrates the effect of the glycosaminoglycans, hyaluron ic acid and chondroitin-6-sulphate (Ch6SO(4)), diamines and a carbodii mide cross-linking agent on the growth of human epidermal cells on col lagen gels. Ch6SO(4) incorporated into collagen gels stimulated cell g rowth rate, but the effect was found to be inconsistent. We found that approximately 50% of the incorporated Ch6SO(4) in the gels leached ou t into the growth medium after the first 3 d in culture, and this is t hought to lead to the inconsistent cell growth response. In order to m inimize the elution of Ch6SO(4) from the gels and thereby maximize its effect on the growth of the keratinocytes, 1-100 mu g ml(-1) Ch6SO(4) was added in the medium. The results showed that Ch6SO(4) at these co ncentrations in the medium did not stimulate the cell growth on either plain collagen gels or gels containing 20% Ch6SO(4). As an alternativ e strategy, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and diamine s (putrescine or diaminohexane) were used to immobilize Ch6SO(4) onto the collagen gels and to cross-link the gels. The cross-linking proces s partially prevented the elution of Ch6SO(4) from the gels. Interesti ngly, only putrescine, not diaminohexane, promoted the growth of kerat inocytes on the cross-linked plain collagen gels. We proposed to devel op an artificial skin substitute containing putrescine as a growth fac tor for the human epidermal cells.