Physical properties and antibacterial activity of chitosan/acemannan mixed systems.

The aim of the present study was to investigate the mechanical and thermal properties of mixed chitosan-acemannan (CS-AC) mixed gels and the antibacterial activity of dilute mixed solutions of both polysaccharides. Physical hydrogels of chitosan comprising varying amounts of non-gelling acemannan were prepared by controlled neutralization of chitosan using ammonia. As the overall acemannan concentration in the mixed hydrogel increased while fixing that of CS, the mechanical strength decreased. These results indicate that AC perturbs the formation of elastic junctions and overall connectivity as it occurs in the isolated CS network. Heterotypic associations between CS and AC leading to the formation of more compact microdomains may be at play in reducing the density of the gel network consolidated by CS, possibly due to shorter gel junctions. Micro-DSC studies at pH 12.0 seem consistent with the suggestion that molecular heterotypic associations between CS and AC may be at play in determining the overall physical properties of the mixed gel systems. In dilute solution, CS showed antimicrobial activity against Staphylococcus aureus but not against Escherichia coli; AC did not exert antimicrobial activity against any of the two bacterial species. In blended solutions of both polysaccharides, as the amount of AC increased, the antimicrobial activity of the system against S. aureus ceased. In conclusion, this study demonstrates that it is feasible to incorporate acemannan in chitosan-acemannan gels and that although the mechanical strength decreases due to the presence of AC, the gel network persists even at high amount of AC. This study anticipates that the CS-AC mixed gels may offer promise for the future development of biomaterials such as scaffolds to be used in wound therapy.

Evaluación in vivo del efecto cicatrizante de un gel a base de quitosano obtenido de exoesqueleto de camarón blanco Litopenaeus vannamei / Healing effect of a chitosan-based gel obtained from the exoskeleton of white shrimp Litopenaeus vannamei and its evaluation in vivo

En México alrededor del 62 % de la población sufre de accidentes causantes de alteraciones en la piel como quemaduras, heridas y diabetes principalmente. Para atender esta problemática, se propone el uso de un gel de quitosano, obtenido del exoesqueleto de camarón ya que presenta actividad antimicrobiana e inmunológica acelerando la cicatrización. Se evaluó el efecto sinérgico sobre la velocidad de cicatrización, aplicándolo en heridas de 1 cm2 infringidas a 48 ratones albinos, agrupados en cuatro tratamientos; Quitosano 0.15 y 0.30 %, producto cicatrizante (Ketanserina al 2 %) y blanco (testigos sin tratamiento). El tiempo para la cicatrización sin tratamiento y el producto comercial fue 14 días, teniendo el control un efecto cicatrizante del 0 %, mientras que los geles de quitosano 0.15 y 0.30 % cicatrizaron en 7 días (P> 0.05) con efecto cicatrizante del 58 % para el quitosano 0.15 y 64 % para el quitosano 0.30.

Skin problems in Mexico have steadily increased (62 %) by burns, wounds and diabetes mainly. To solve this problem, chitosan can be implemented; this polysaccharide has an antimicrobial and immunology activity against bacteria and fungi, accelerating healing. Therefore, synergistic effect of chitosan gel on the rate of healing, obtained from the exoskeleton of shrimp, that was evaluated. This was tested by applying it 1 cm2 of inflicted wounds of 48 albino mice, of 45 days old and between 23 to 26 g of weight, during 14 days, and grouped into four treatments: 1) 0.15 % chitosan 2) 0.30 % chitosan, 3) commercial product 2 % Ketanserin and 4) A batch of untreated controls. The time required for healing without treatment was 14 days and with the utilization of 0.30 % chitosan gel was achieved in 7 days (P> 0.05) with the healing effect 58 % for the chitosan 0.15 and 64 % for chitosan 0.30.