Title : Polysaccharide Based Nanotubes for Medical Applications
Abstract:
β-1,3-glucan polysaccharides are important biomaterials with a comb-like structure, which treat diseases and promote health in a number of important ways including antitumor, immune-stimulating activities, etc. Their well-known triple-helix conformation in water has so far been exploited for in-situ encapsulation of some drugs and nanoparticles; however, the the range of medical applications of glucans is limited by solubility in water
Using our original concept of successful modification and stabilization of triple-helix structure in water and simultaneous strengthening of nanotube walls by borate-based complex/covalent bonds formation, we have prepared stable insoluble glucan nanotubes (GNT). The nanotubes based on glucan isolated from Auricularia auricula-judae mushroom have a diameter of ~50 nm and wall thickness of several nanometers, i.e., the geometry similar to carbon nanotubes. The high reinforcing effect of GNT in a nanocomposite with methylcellulose matrix causing increase in modulus from ~ 3500 MPa to ~ 4000 MPa with 5 % content indicates that modulus of GNT exceeds 10 000 MPa (according to Halpin-Tsai model with aspect ratio 20). The GNT represent a new class of medical material which can be used in tissue engineering as important component of scaffolds and for reinforcement of many medicinal systems. In addition to expected synergic contribution to medicinal activities, GNT have also a potential of exploitation as nanocontainer for drug delivery and controlled release.
Upgrade of GNT using modified borate complex and functionalization of glucan chains is highlighted. This study also includes application of other glucans, e.g. those isolated from Schizophyllum commune together with surface decoration of GNT with proteins and polydopamine. GNT were applied to improve self-healing hyaluronate hydrogels based on Schiff base reaction. Important feature is possible replacement of reactive hyaluronic acid by GNT with identical functionality or their parallel application to control the network density. From the results of mechanical testing, it is obvious that application of neat and functionalized GNT can modify mechanical properties of a hydrogel in a wide range, which is accompanied by simultaneous contribution to its wound healing effectivity, as confirmed by the wound-healing assay with cell-based model.
This work was supported by Ministry of Education Youth and Sports of the Czech Republic (Grant LUAUS 23004)
