A review on tragacanth gum: A promising natural polysaccharide in drug delivery and cell therapy.

Tragacanth is an abundant natural gum extracted from some plants and is dried for use in various applications from industry to biomedicines. It is a cost-effective and easily accessible polysaccharide with desirable biocompatibility and biodegradability, drawing much attention for use in new biomedical applications such as wound healing and tissue engineering. Moreover, this anionic polysaccharide with a highly branched structure has been used as an emulsifier and thickening agent in pharmaceutical applications. In addition, this gum has been introduced as an appealing biomaterial for producing engineering tools in drug delivery. Furthermore, the biological properties of tragacanth gum have made it a favorable biomaterial in cell therapies, and tissue engineering. This review aims to discuss the recent studies on this natural gum as a potential carrier for different drugs and cells.

Anti-fatigue, highly resilient photocrosslinkable gellan gum hydrogels reinforced by flexible nanoparticulate polyurethane multi-crosslinkers.

In this study, multifunctional polyurethane nanoparticles (MPUNs) were embedded into the methacrylated gellan gum (MGG) to prepare stimuli-responsive hydrogels with improved mechanical properties including remarkable fatigue resistance and excellent self-recoverability. The photocurable MPUNs/MGG nanocomposite hydrogels with different formulations were synthesized through a facile and green solution mixing method. The result obtained from mechanical analysis displayed an excellent improvement in compression strength (120 6 ± 83.7 kPa) and ultimate strain (94.2 ± 2.7%) in the optimized formulation. Furthermore, the optimized formulation could restore approximately its original shape after continuous loading-unloading compression tests over 100 cycles which might result from its favorable crosslinked structure. These reinforced hydrogels exhibited a dual physical and chemical crosslinking mechanism based on the hydrogen bonding formation and photocrosslinking of methacrylate functional groups, respectively. Interestingly, the nanocomposite hydrogels exhibited no significant cytotoxicity to human dermal fibroblast cells which made them suitable as the appropriate biomaterials for the engineering of soft tissues.

Mechanical reinforcement of gellan gum polyelectrolyte hydrogels by cationic polyurethane soft nanoparticles.

Novel mechanically reinforced nanocomposite hydrogels (NCHs) were developed based on methacrylated gellan gum (MGG) and cationic polyurethane nanoparticles (CPUNs) through a green chemical approach. A series of NCHs were synthesized by the incorporation of CPUNs with weight ratios of 0, 10, 30 and 50 w/w% into the MGG solution, with two different methacrylation degrees (1.2, 5.6%). The chemical structure, morphology, mechanical properties, stimuli-responsivity and cytotoxicity of synthesized NCHs were investigated. Analysis of the hydrogels mechanical testing demonstrated that the addition of CPUNs affords the significant increase in compressive properties. Meanwhile, the formulation of NCH containing the MGG with lower methacrylation degree and 30 w/w% CPUNs showed the highest mechanical properties. Furthermore, equilibrium swelling ratio of the hydrogels decreased by CPUNs addition. Finally, it is worth mentioning that NCHs showed no significant toxicity to human dermal fibroblast cells (HDFs) which idealize them as the suitable hydrogels for biomedical applications.

Guanidine hydrochloride embedded polyurethanes as antimicrobial and absorptive wound dressing membranes with promising cytocompatibility.

Preparation and assessments of novel absorptive wound dressing materials with efficient antimicrobial activity as well as very good cytocompatibility were described in this work. An amine terminated poly(hexamethylene guanidine hydrochloride) was prepared and used as curing agent of different epoxy-terminated polyurethane prepolymers. The structures of prepared materials were elucidated by evaluation of their (1)H NMR and FTIR spectra. The recorded tensile strength of membranes confirmed the excellent dimensional stability of the film type dressings even at fully hydrated conditions. Therefore, these dressings could protect the wound bed from external forces during the healing period. The structurally optimized dressing membranes could preserve the desired moist environment over the wounded area, as a result of their balanced equilibrium, water absorption and water vapor transmission rate. Therefore, a very good condition for stimulation of self-healing of wound bed was attained. Also, owing to the presence of guanidine hydrochloride moieties embedded into the structure of dressings, efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were detected. In vitro cytotoxicity assay of the prepared dressings revealed cytocompatibility of these materials against fibroblast cells. Therefore, they could support cell growth and proliferation at the wounded area.