Rheological behavior of anionic collagen injectable gels in the presence of rhamsan for plastic surgery applications

Abstract

The present paper describes the rheological properties of anionic collagen gels and anionic collagen:rhamsan composites gels in the concentration of 0.7, 4 and 6%, estimated to be used as injectable biomaterials for plastic reconstruction. Rheological studies of these gels showed that independently of pH, composition and concentration the viscoelastic behavior was dependent on the frequency, with the storage modulus always greater than the loss modulus (G' > G'' and delta < 45 degrees ). Creep experiments showed that anionic collagen:rhamsan composites equilibrated at pH 7.4 were less elastic and more susceptible to deformation in comparison to gels equilibrated at pH 3.5. Flow experiments indicated that the force needed for the extrusion of anionic collagen:rhamsan composites, in comparison to anionic collagen, was significantly smaller and with a smoother flow, suggesting the association with rhamsan may be a good alternative in the replacement of glutaraldehyde to stabilize the microfibril assembly of commercial collagen gel preparations. Finally, on the basis of dynamic viscosity profiles found for different preparations, some of these composites are potential candidates to be utilized in laryngology.

A Microplate Compression Method for Elastic Modulus Measurement of Soft and Viscoelastic Collagen Microspheres

“…The storage modulus of anionic collagen hydrogel has been found to be between 8 and 80 Pa. 13 In the presence of fibroblasts, collagen hydrogel at 0.3 mg/mL contracted to give a stiffer gel with a linear elastic modulus of 1.54 ± 0.507 kPa. 17 Although it is difficult to directly compare the results of the current method with those in the literature as the methods for measurement are different, the effect of cell-induced collagen gel contraction on the stiffness of the structure has been clearly revealed by the current microplate compression method, in that the mesenchymal stem cell-encapsulated collagen microspheres are several orders of magnitude stiffer than those fabricated without cells.…”

Modeling the Electromobility of Type-I Collagen Molecules in the Electrochemical Fabrication of Dense and Aligned Tissue Constructs

“…The viscosity of collagenous medium is dependent on pH 11,13 ; therefore, the drag force is a function of distance between the electrodes. The pH of dialyzed collagen solutions (Nutragen Ò , 6 mg/mL, Advanced Biomatrix, San Diego, CA) were adjusted to various values in the range of 3 and 11 using 0.1 N HCl or 0.1 N NaOH solutions.…”

Vaginal gel drug delivery systems: understanding rheological characteristics and performance

“…Interestingly, there is a major deficit of literature describing the use of creep rheology to characterize vaginal gels. Conversely, creep rheology has been used extensively to characterize a range of gel-based pharmaceutical materials [48][49][50]. In relation to vaginal gels, creep rheology is a useful tool in determining the balance of viscous--elastic character within a viscoelastic gel and how this balance may shift as a function of time under the application of small stress values.…”