Gel Beads Composed of Chitosan and Polyacids and Their Blood Compatibility

Chitosan gel beads were prepared as a model for new chitosan materials and their blood compatibility was evaluated in vitroin human pool plasma and in human whole blood. The one-stage method for the preparation of monolithic beads consisted of performing a template polymerization of 2-acryloylamido-2-methylpropanesulfonic acid (AMPS) or copolymerization of AMPS and acrylic acid. Monolithic beads of semi-interpenetrating networks chitosan/copolymer were prepared in the presence of a cross-linking agent. The equilibrium degree of swelling of the beads was dependent on the composition. Reservoir-type beads consisting of a chitosan core and a coating of polyelectrolyte complex with anticoagulant activity and chitosan were also prepared. The reservoir-type beads and the monolithic beads showed improved compatibility with blood in comparison with the uncoated chitosan beads.

Curcumin-loaded poly(l-lactide-co-D,l-lactide) electrospun fibers: Preparation and antioxidant, anticoagulant, and antibacterial properties

Fibrous materials of poly(l-lactide- co-d,l-lactide), poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol), and curcumin were prepared by electrospinning. The incorporation of poly(ethylene glycol) in the fibers caused a decrease in the mean fiber diameters down to 700 nm and in the water contact angle value, the latter being equal to 0 at poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol) 60/40 weight ratio. The water contact angle values of poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials considerably exceeded those of films of the same composition (approximately 120° as compared to approximately 95°, for electrospun mats and solution-cast films, respectively). Curcumin affected the thermal stability of the fibrous materials and the crystallinity degree of the polymers. The mechanical properties of the electrospun materials also depended on the composition of the polymer matrix and the amount of curcumin therein. In the curcumin-containing fibers, curcumin was found in the amorphous state, while higher antioxidant activity was exhibited by poly(l-lactide- co-d,l-lactide)/poly(ethylene glycol)/curcumin fibrous materials. In vitro determination of the activated partial thromboplastin time and prothrombin time showed that poly(l-lactide- co-d,l-lactide)/curcumin fibrous materials displayed anticoagulant activity. Antibacterial effect toward Staphylococcus aureus was manifested by the curcumin-containing mats.

Polylactide stereocomplex-based electrospun materials possessing surface with antibacterial and hemostatic properties

Novel fibrous materials of stereocomplex between high-molecular-weight poly(d- or l-)lactide (HMPDLA or HMPLLA) and diblock copolymers consisting of poly(l- or d-)lactide and poly(N,N-dimethylamino-2-ethyl methacrylate) blocks, respectively (PLLA-block-PDMAEMA or PDLA-block-PDMAEMA), were prepared by solution electrospinning. Fibers with mean diameters ranging from 1400 to 1700 nm were obtained. The stereocomplex formation was evidenced by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses. Annealing at 100 degrees C for 8 h resulted in the appearance of crystalline peaks at 2theta values of 12, 21, and 24 degrees for PLA stereocomplex. X-ray photoelectron spectroscopy (XPS) analyses revealed the gradient composition of the fibers with a surface enriched in tertiary amino groups from PDMAEMA blocks. The availability of tertiary amino groups imparts hemostatic and antibacterial properties to the stereocomplex fibrous materials, as indicated by the performed tests on blood cells and on pathogenic microorganisms.

Polyelectrolyte complexes based on (quaternized) poly[(2-dimethylamino)ethyl methacrylate]: behavior in contact with blood

Polyelectrolyte complexes (PECs) between (quaternized) poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) and (crosslinked) N-carboxyethylchitosan (CECh) or poly(2-acrylamido-2-methylpropane sodium sulfonate) (PAMPSNa) were prepared and characterized in terms of their stability, equilibrium water content, and surface morphology. The evaluation of the behavior of the studied PECs in contact with blood revealed that the (crosslinked) CECh/(quaternized) PDMAEMA complexes had lost the inherent PDMAEMA cytotoxicity but still preserved haemostatic activity. In contrast, the complex formation between (quaternized) PDMAEMA and PAMPSNa allowed the preparation of materials with improved blood compatibility.

Antiviral activity of tetrahydro-2(1H)-pyrimidinones and related compounds

24 derivatives of tetrahydro-2(1H)-pyrimidinone and related compounds were tested in vitro for antiviral activity against representatives of six viral taxonomic groups. The screening was carried out by a two-stage procedure including the agar-diffusion plaque-inhibition test and the one-step growth cycle setup. A distinct activity of three mono- and bis-morpholinomethyl derivatives of tetrahydro-2(1H)-pyrimidinone (THP), 1,3-bis(piperidinomethyl)-THP, the 1-morpholinomethyl derivative of tetrahydro-2(1H)-pyrimidinethione (THPT) and the related N,N'-bis(morpholinomethyl)-urea against the fowl plague virus was established. In the one-step growth cycle setup these compounds inhibited 87.5-99.6% of the infectious virus yield. Two of the compounds, namely 1-morpholinomethyl derivatives of THP and THPT manifested a strong inhibitory effect on the reproduction of Semliki Forest virus as well, exceeding 99.9% in the one-step growth cycle test. A borderline effect was observed in some derivatives against vaccinia virus and Newcastle disease virus. The structure-activity relationship of this group of compounds is discussed.