MARA TANIA SILVA ALCANTARA

MARA TANIA SILVA ALCANTARA

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Simultaneous hydrogel crosslinking and silver nanoparticle formation by using ionizing radiation to obtain antimicrobial hydrogels
2019 - ALCANTARA, M.T.S.; LINCOPAN, N.; SANTOS, P.M.; RAMIREZ, P.A.; BRANT, A.J.C.; RIELLA, H.G.; LUGAO, A.B.
Hydrogel dressings are crosslinked hydrophilic polymers able of swelling in presence of water and can be used in many different types of wound care. In turn, in wound care, silver has been used for a long time as an effective antimicrobial agent. Recent studies have demonstrated an increase of its antimicrobial action when it is used at nanometer scale, that is, as silver nanoparticles (AgNPs), which have anti-inflammatory effect on infected wounds, rashes, and mesh skin grafts. The objective of this work was to study hydrogel dressings containing AgNPs from silver nitrate, synthesized by radiation involving the formation of silver nanoparticles with simultaneous occurrence of crosslinking and sterilization of the polymer systems. One of the hydrogels was prepared with poly(N-vinyl-2- pyrrolidone) (PVP) and the other with poly(vinyl alcohol) (PVA) as main studied polymers. An aqueous solution of AgNO3 was added to both polymer systems separately. The AgNPs synthesis, polymer crosslinking and dressing sterilization were achieved simultaneously by irradiating the resultant solutions with gamma-rays from a 60Co source. Gel fraction, swelling in reverse osmosis water, SEM-EDS, UVvisible spectroscopy, and antimicrobial activity were performed and characterized. The obtained results showed that the dressings have a soft consistency, high degree of crosslinking and swelling, homogeneous distribution of AgNPs with peaks of plasmonic bands about 400 nm, but only PVP hydrogel showed antimicrobial properties to P. aeruginosa and normal S. aureus. Moreover, this hydrogel also showed antimicrobial properties to S. aureus strain multiresistant to penicillins, cephalosporins, carbapenems, sulfonamides, tetracyclines, quinolones, and aminoglycosides, whereas the PVA hydrogel showed antimicrobial properties to P. aeruginosa and bacteriostatic activity to S. aureus. The results suggest that both synthesized dressings have potential for use in wounds and burns infected with gram-positive and gram-negative bacteria.
Synthesis and in vivo behavior of PVP/CMC/agar hydrogel membranes impregnated with silver nanoparticles for wound healing applications
2018 - LIMA, GABRIEL G. de; LIMA, DARLLA W.F. de; OLIVEIRA, MARIA J.A. de; LUGAO, ADEMAR B.; ALCANTARA, MARA T.S.; DEVINE, DECLAN M.; SA, MARCELO J.C. de
The field of wound healing has seen an increase in research activity in wound care and hydrogel-based dressings have been targeted as a solution for these applications. Hydrogels with silver nanoparticles can present many advantages for this field. However, if the aggregation and sterilization of this product have not been carefully considered, the effectiveness or use could be limited. Therefore, in the current study, a hydrogel-based wound dressing membrane was developed using polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), agar, and carboxymethyl cellulose (CMC). Silver ions (Ag+) were dispersed in the polymer matrix and its reduction with formation of a hydrogel and silver nanoparticles was performed using 60Co gamma irradiation to enhance the dressings antimicrobial properties. The resulting hydrogel presented a high degree of swelling and a good size control of silver nanoparticles. The incorporation of AgNPs was confirmed via Raman spectroscopy and the samples presented no signs of toxicity in vitro as assessed using an elution assay with neutral red uptake as the cytotoxic end point. Membranes were tested in vivo using a full thickness defeat model in rabbits. Postmortem histopathological analysis indicated that the use of the hydrogel membranes that incorporated AgNPs had a stimulatory action on wound healing as evidenced by a high intensity of fibroblasts and neovascularization in the tissue, which promoted a faster healing process when compared to the untreated wounds. We demonstrate the possibility of producing a hydrogel with good size control of AgNPs, which can also be directly sterilized within the formation of this material via gamma irradiation. Furthermore, the mechanism of hydrogel healing, in vivo, with silver nanoparticles was found to have a direct correlation of silver nanoparticles with in vitro cell results.
Influence of dissolution processing of PVA blends on the characteristics of their hydrogels synthesized by radiation - Part I: Gel fraction, swelling, and mechanical properties
2012 - ALCANTARA, M.T.S.; BRANT, A.J.C.; GIANNINI, D.R.; PESSOA, J.O.C.P.; ANDRADE, A.B.; RIELLA, H.G.; LUGAO, A.B.
Influence of gamma radiation onto polymeric matrix with papain
2010 - ZULLI, GISLAINE; LOPES, PATRICIA S.; VELASCO, MARIA V.R.; ALCANTARA, MARA T.S.; ROGERO, SIZUE O.; LUGAO, ADEMAR B.; MATHOR, MONICA B.
In vitro and in vivo toxicology evaluation to determine suitable biomedical polymers for development of a papain-containing drug delivery system
2011 - ZULLI, GISLAINE; LOPES, PATRICIA S.; ALCANTARA, MARA T.S.; VELASCO, MARIA V.R.; MIYAMARU, LIGIA L.; BARBARA, MARIA C.S.; ROGERO, SIZUE O.; LUGAO, ADEMAR B.; MATHOR, MONICA B.