Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers Leonardo Marques, 1 Leandro A. Holgado, 1 Rebeca D. Sim~ oes, 2 Jo~ ao D. A. S. Pereira, 2 Juliana F. Floriano, 3 L  ıgia S. L. S. Mota, 4 Carlos F. O. Graeff, 3 Carlos J. L. Constantino, 2 Miguel. A. Rodriguez-Perez, 5 Mariza Matsumoto, 1 Angela Kinoshita 1 1 Universidade Sagrado Corac ¸~ ao – USC, Bauru, S~ ao Paulo, Brazil 2 Faculdade de Ci^ encias e Tecnologia, UNESP Universidade Estadual Paulista, Presidente Prudente, S~ ao Paulo, Brazil 3 Faculdade de Ci^ encias, UNESP Universidade Estadual Paulista, Bauru, S~ ao Paulo, Brazil 4 Instituto de Bioci^ encias, UNESP Universidade Estadual Paulista, Bauru, S~ ao Paulo, Brazil 5 Condensed Matter Physics Department, CellMat Laboratory, Faculty of Science, University of Valladolid, Valladolid, Spain Received 27 August 2012; revised 5 February 2013; accepted 6 March 2013 Published online 10 May 2013 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jbm.b.32941 Abstract: Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with nat- ural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associ- ated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcuta- neous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was eval- uated by histomorphometry of the inflammatory cells. Chem- ical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron mi- croscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflamma- tory pattern, characterized by a reduction of polymorphonu- clear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal–Wallis). On day 60, micro- scopic analysis showed regression of the chronic inflamma- tory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the me- dium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. V C 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1284–1293, 2013. Key Words: biomaterial, piezoelectricity, tissue reaction, cyto- toxicity, PVDF How to cite this article: Marques L, Holgado LA, Sim~ oes RD, Pereira JDAS, Floriano JF, Mota LSLS, Graeff CFO, Constantino CJL, Rodriguez-Perez MA, Matsumoto M, Kinoshita A. 2013. Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers. J Biomed Mater Res Part B 2013:101: 1284–1293. INTRODUCTION Currently the gold standard for the treatment of large bone defects is the autologous bone that stimulates a series of cellular and molecular events that result in repair of the recipient area. Autologous bone is obtained from various donor sites; however, the morbidity of this procedure, the technical difficulty, and the high costs are factors that make necessary the search for new biomaterials with properties that enhance bone healing. 1,2 The most commonly used bioabsorbable polymers for bone tissue engineering are saturated aliphatic polymers such as poly(lactic acid) (PLA), poly(glycolic acid), 3 polycap- rolactone (PCL), and their copolymer, among others. These based polymers and their derivatives have been successfully used as internal fracture fixation devices (orthopedic bioab- sorbable osteofixation systems) for long bones in human, since the mid-1980. 4 Another polymeric systems used are starch-based blends. The starch is blended with thermoplas- tic polymers to increase their resistance against thermome- chanical degradation and make them less brittle and more easily processed. Blends of starch with PCL and PLA have Correspondence to: A. Kinoshita; e-mail: angela.kinoshita@usc.br Contract grant sponsors: FAPESP (Fundac ¸~ ao de Amparo  a Pesquisa do Estado de S~ ao Paulo), CNPq (Conselho Nacional de Desenvolvimento Cient  ıfico e Tecnol  ogico), CAPES (Coordenac ¸~ ao de Aperfeic¸oamento de Pessoal de N ıvel Superior), FAP=USC (Fundac ¸~ ao de Amparo  a Pesquisa da Universidade Sagrado Corac ¸~ ao) 1284 V C 2013 WILEY PERIODICALS, INC.