Advanced pullulan nanofibers reinforced by cellulose fibrils as drug carriers for salicylic acid.

The goal of the current work is to showcase the synthesis of homogeneous pullulan nanofibers that are strengthened by the addition of cellulose nanofibrils (CNF). One of the main difficulties this study faced was determining the ideal water/organic solvent ratio for the electrospinning process, which would allow for the maximum reduction in the amount of organic solvent (DMF or DMSO) needed. The rheological behavior of electrospinning solutions was modulated by varying both, the pullulan concentration and solvent system composition.

Biomaterials Based on Chitosan and Polyvinyl Alcohol as a Drug Delivery System with Wound-Healing Effects.

The excellent biological properties of chitosan (CS) together with the increased oxygen permeability of polyvinyl alcohol (PVA) were the prerequisites for the creation of a wound healing dressing that would also function as a system for L-arginine (L-arg) and caffeine (Caff) delivery. Using the freezing/thawing method, 12 hydrogels were obtained in PVA:CS polymer ratios of 90:10, 75:25, and 60:40, and all were loaded with L-arg, Caff, and the mixture of L-arg and Caff, respectively. Afterwards, an inorganic material (zeolite-Z) was added to the best polymeric ratio (75:25) and loaded with active substances.

Hemostatic Cryogels Based on Oxidized Pullulan/Dopamine with Potential Use as Wound Dressings.

The impetus for research into hydrogels based on selectively oxidized polysaccharides has been stimulated by the diversity of potential biomedical applications. Towards the development of a hemostatic wound dressing in this study, we creatively combined the (hemi)acetal and Schiff base bonds to prepare a series of multifunctional cryogels based on dialdehyde pullulan and dopamine. The designed structures were verified by NMR and FTIR spectroscopy.

Pullulan Oxidation in the Presence of Hydrogen Peroxide and -Hydroxyphthalimide.

The C-6 in the maltotriose unit of pullulan was oxidized in an alkaline medium (pH = 10), utilizing a green method that included hydrogen peroxide (HO) as an oxidant and -hydroxyphthalimide (NHPI) as a catalyst for various reaction times. The structure of the resulting oxidized pullulans (PO) was carefully characterized by titration, intrinsic viscosity, FTIR, C-NMR, and zeta potential. The content of carboxyl groups in PO was dependent on reaction time and varied accordingly.

Affordable Magnetic Hydrogels Prepared from Biocompatible and Biodegradable Sources.

Magnetic hydrogels composed of poly(vinyl alcohol) (PVA)/water-soluble tricarboxy cellulose (CO)/magnetic fluids (MFs) have been prepared by a freeze-thaw cycle technique. The system designed here combines the renewability and biocompatibility aspects of PVA and CO, as well as the magnetic properties of MFs, thereby offering special properties to the final product with potential applications in medicine. In the first step, the water-soluble CO is synthesized using a one-shot oxidation procedure and then the aqueous solutions of CO are mixed with PVA solutions and magnetic fluids in the absence of any additional cross-linking agent.

Recyclable Polymer-Supported -Hydroxyphthalimide Catalysts for Selective Oxidation of Pullulan.

This paper proposes a convenient route to oxidize the -CH-OH groups in the water-soluble pullulan, using a new catalytic polymer-supported -hydroxyphthalimide (NHPI) immobilized on polystyrene. The protocol involves the presence of sodium hypochlorite and sodium bromide. The conversion is possible at room temperature, atmospheric pressure, and pH = 10.

Physical Hydrogels of Oxidized Polysaccharides and Poly(Vinyl Alcohol) for Wound Dressing Applications.

Two natural polymers, i.e., cellulose and water soluble pullulan, have been selectively oxidized employing the TEMPO-mediated protocol, to allow the introduction of C-OOH groups.

Self-healing hydrogels of oxidized pullulan and poly(vinyl alcohol).

Composite hydrogels of poly(vinyl alcohol) (PVA) and C-fully oxidized pullulan (OxP) were prepared and investigated. Hydrogels with different content of OxP into the PVA matrix were prepared by freezing/thawing method. FTIR and NMR were used to assess the degree of interaction between the two polymers into the physical network.

Green route for the fabrication of self-healable hydrogels based on tricarboxy cellulose and poly(vinyl alcohol).

A new approach for the preparation of poly (vinyl alcohol) (PVA) - cellulose based composite hydrogels by freezing/thawing method was conceived. We synthesized firstly the tricarboxy cellulose (OxC) (bearing three carboxyl groups in one anhydroglucose unit) using a one shot oxidation procedure and subsequently, the aqueous solutions of OxC were mixed with PVA solutions in different ratios, in the absence of any supplementary cross-linking agent. The spectral methods, FTIR, H, C NMR, as well as rheology measurements were used to assess the degree of interaction between the two components.