Use of polyphosphazenes for skeletal tissue regeneration

Abstract

The hydrolytically unstable polyphosphazenes, poly [(imidazolyl) (methylphenoxy) phosphazenes] and poly [ethyl glycinato) (methylphenoxy) phosphazenes], were studied as potential polymeric supports for cells in tissue regeneration. For bone repair, their specific function would be to support osteoblast growth, forming a bone-polymer matrix. MC3T3-E1 cells (an osteogenic cell line) were seeded onto polymer matrices and cell adhesion and growth as well as polymer degradation were examined. Both imidazolyl- and ethyl glycinato-substituted polyphosphazenes supported the growth of MC3T3-E1 cells. An increase in the content of the imidazolyl side group resulted in a reduction in cell attachment and growth on the polymer surface and an increase in the rate of degradation of the polymer. In contrast, substitution with the ethyl glycinato group favored increased cell adhesion and growth and also an increase in the rate of degradation of the polymers. Thus, the polyphosphazenes represent a system whereby cell growth and degradation can be modulated by varying the nature of the hydrolytically unstable side chain. This in vitro evaluation suggests that the polyphosphazenes may be suitable candidate biomaterials for the construction of a cell-polymer matrix for tissue regeneration.

Retention and activity of BMP‐2 in hyaluronic acid‐based scaffolds in vitro

“…Conditioned media collected 2 days before each time point (3,7,14, and 28 days) were used. Briefly, the samples were incubated with goat anti-mouse osteocalcin and 125 I mouse osteocalcin followed by donkey anti-goat IgG.…”

“…A variety of synthetic (e.g., poly-lactic/glycolic acid) or natural polymers (e.g., collagen) have been used as delivery vehicles for cells or growth/morphogenetic factors [e.g., transforming growth factors, bone morphogenetic proteins (BMPs)]. [7][8][9][10] Polymeric scaffolds fabricated using various methods [11][12][13][14] have been used for cartilage repair, 1 nonunion fracture defects, 8,9 oral/maxillofacial defects, [15][16][17][18][19] , and spinal fusion 20,21 as well as nerve 22 and liver 23 tissue repair. Derivatized hyaluronic acid (Hyaff-11) is a new class of a semisynthetic biopolymer that can be fabricated into porous scaffolds for tissue reconstruction and repair.…”

Miscibility and in vitro osteocompatibility of biodegradable blends of poly[(ethyl alanato) (p-phenyl phenoxy) phosphazene] and poly(lactic acid-glycolic acid)

“…Also the degradation rates can be modified by varying the nature and ratio of the side groups [11][12][13][14]. Thus, amino acid ester polyphosphazenes have been found to be attractive candidates for biomedical applications [15][16][17]. We have recently demonstrated relatively good mechanical properties, tunable degradation rate, and excellent osteocompatibility of alanine ethyl ester and p-phenylphenoxy cosubstituted polyphosphazenes both in vitro and in vivo [14,18,19].…”

Antimicrobial and Biological Effects of Bomphos and Phomphos on Bacterial and Yeast Cells

“…Also, the fungal growth requires some compounds containing phosphorus and nitrogen atoms (25). The monophosphazene molecules contain phosphorus and nitrogen atoms and therefore they have a positive effect on the growth yeast cells for both S. cerevisiae and C. albicans Ibim et al (27) and Laurencin et al (28) indicated that polyphosphazenes have positive effects on cells and tissue cultures and are required for cell growth and tissue regeneration. Also, Veromese et al (29) found that antibacterial or anti-inflammatory drugs, useful in periodontal tissue regeneration, could be entrapped in the phosphazene membranes and realized both in vitro and in vivo at such a rate that ensured therapeutic concentrations in the surroundings tissue.…”