RESUMEN
Ideal wound dressings should be biocompatible, exhibit high antibacterial activity, and promote blood coagulation. To impart these imperative functions, carboxymethyl-kappa-carrageenan was incorporated into poly(vinyl alcohol) nanofibers (PVA-CMKC). The antibacterial activity of the nanofibers was evaluated. Adsorption of two important blood proteins, fibrinogen and albumin, was also assessed. The adhesion and activation of platelets, and the clotting of whole blood were evaluated to characterize the ability of the nanofibers to promote hemostasis. Adhesion and morphology of both Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using fluorescence microscopy and scanning electron microscopy. CMKC-containing nanofibers demonstrated significant increases in platelet adhesion and activation, percentage of coagulation in whole blood clotting test and fibrinogen adsorption, compared to PVA nanofibers, showing blood coagulation activity. Incorporating CMKC also reduces adhesion and viability of S. aureus and P. aeruginosa bacteria after 24 h of incubation. PVA-CMKC nanofibers show potential application as dressings for wound healing applications.
Asunto(s)
Antibacterianos/farmacología , Coagulación Sanguínea/efectos de los fármacos , Carragenina/farmacología , Nanofibras/química , Cicatrización de Heridas/efectos de los fármacos , Albúminas/metabolismo , Antibacterianos/química , Vendajes , Materiales Biocompatibles/farmacología , Carragenina/química , Fibrinógeno/metabolismo , Humanos , Microscopía Electrónica de Rastreo/métodos , Activación Plaquetaria/efectos de los fármacos , Alcohol Polivinílico/química , Alcohol Polivinílico/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacosRESUMEN
This study presents a new type of biocompatible nanofiber based on poly(vinyl alcohol) (PVA) and carboxymethyl-kappa-carrageenan (CMKC) blends, produced with no generation of hazardous waste. The nanofibers are produced by electrospinning using PVA:CMKC blends with ratios of 1:0, 1:0.25, 1:0.4, 1:0.5, and 1:0.75 (w/w PVA:CMKC) in aqueous solution, followed by thermal crosslinking. The diameter of the fibers is in the nanometer scale and below 300 nm. Fourier transform infrared spectroscopy shows the presence of the carboxyl and sulfate groups in all the fibers with CMKC. The nanofibers from water-soluble polymers are stabilized by thermal crosslinking. The incorporation of CMKC improves cytocompatibility, biodegradability, cell growth, and cell adhesion, compared to PVA nanofibers. Furthermore, the incorporation of CMKC modulates phenotype of human adipose-derived stem cells (ADSCs). PVA/CMKC nanofibers enhance ADSC response to osteogenic differentiation signals and are therefore good candidates for application in tissue engineering to support stem cells.
Asunto(s)
Materiales Biocompatibles/farmacología , Nanofibras/química , Osteogénesis/efectos de los fármacos , Ingeniería de Tejidos , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/química , Carragenina/química , Carragenina/farmacología , Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Humanos , Microscopía Electrónica de Rastreo , Alcohol Polivinílico/química , Alcohol Polivinílico/farmacología , Espectroscopía Infrarroja por Transformada de Fourier , Andamios del Tejido/químicaRESUMEN
To develop hemocompatible surfaces, a cationic tannin derivate (TN) was used to prepare polyelectrolyte multilayers (PEMs) with the glycosaminoglycans heparin (HEP) and chondroitin sulfate (CS). The surface chemistry of the PEMs was characterized using X-ray photoelectron spectroscopy and water contact angle measurements. PEMs assembled with chitosan (CHI) and HEP or CS were used as controls. We investigate the hemocompatibility of PEMs by analyzing the adsorption of key blood serum proteins, adhesion and activation of platelets, and blood clotting kinetics. TN- and CHI-based PEMs adsorb similar amounts of albumin, whereas fibrinogen adsorption was more pronounced on TN-based PEMs, due to strong association with catechol groups. However, TN-based PEMs significantly reduce both platelet adhesion and platelet activation, while CHI-based PEMs promote platelet adhesion and activation. The whole-blood clotting kinetics assay also shows lower blood coagulation on TN-based PEMs. TN is an amphoteric, cationic, condensed tannin derivative with resonance structures. It also contains catechol groups, which are similar to those in mussel adhesive protein. These chemical features enable strong association with fibrinogen, which promotes the platelet-repelling effect. This study provides a new perspective for understanding platelet adhesion and activation on biomaterial surfaces, toward the development of new blood-compatible surfaces using a tannin derivative-based polymer.
Asunto(s)
Materiales Biocompatibles/química , Plaquetas/metabolismo , Proteínas Sanguíneas/química , Polielectrolitos/química , Taninos/química , Adsorción , Materiales Biocompatibles/farmacología , Coagulación Sanguínea/efectos de los fármacos , Plaquetas/citología , Plaquetas/efectos de los fármacos , Quitosano/química , Sulfatos de Condroitina/química , Heparina/química , Humanos , Activación Plaquetaria/efectos de los fármacos , Adhesividad Plaquetaria/efectos de los fármacos , Polifenoles/química , Propiedades de Superficie , HumectabilidadRESUMEN
Modifying materials with biocompatible surface coatings is an important method for controlling cell responses to biomaterials. In this work, tanfloc (TN), a cationic tannin-derivative polymer was assembled with heparin (HEP) and chondroitin sulfate (CS), using the layer-by-layer (LbL) approach, to build polyelectrolyte multilayers (PEMs) and to design cytocompatible coatings. LbL deposition was monitored through Fourier-transform surface plasmon resonance, and characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The response of human adipose-derived stem cells (ADSCs) was evaluated in vitro. All of the TN-containing PEMs exhibit cytocompatibility and support adhesion, proliferation, and the spreading of ADSCs after 7 days of culture. HEP-TN PEM assembly with 11 layers (HEP-TN11) supports the greatest rate of cell proliferation. When TN is the terminal layer of the PEM, the surfaces promote the spreading of ADSCs, indicating that the surface charge and PEM terminal layer are key determinants of the microenvironmental niche that control cellular response. The promotion of stem cell attachment and proliferation makes these surface coatings potentially useful for biomedical implants and regenerative medicine.
RESUMEN
The present study aimed to study the reaction conditions of grafting of acrylamide on xanthan gum. It was analyzed the influence of reaction conditions, mainly type of initiator activation, initiator concentration and initiator/acrylamide ratio, on graft parameters and copolymer properties. Potassium persulfate was employed as an initiator and heating or N,N,N',N'-tetramethylethylenediamine was used to activate the initiator. Reaction time and initiator concentration were varied and final values for grafting percentage and grafting efficiency were the same for both methods, whereas speed in reaching these values differs from one technique to another. We found that reaction time was inversely proportional to intrinsic viscosity, likely due to main chain degradation promoted by potassium persulfate (KPS); furthermore, the increasing in the KPS concentration lowers grafting percentage, acrylamide conversion and chain degradation, possibly as a result of O(2) formation at high KPS concentrations.