Hydrogel Surface Based on PINIPAm as Scaffolds for Bovine Fetal Fibroblast Culture

RIVERO, REBECA; ALUSTIZA, FABRISIO; FORCATO, DIEGO; CAPELLA, VIRGINIA; MIRAS, MARÍA CRISTINA; BARBERO, CESAR; BOSCH, PABLO; RIVAROLA, CLAUDIA

Rosario

Congreso; 8vo Congreso Latinoamericano de órganos Artificiales, Biomateriales e Ingeniería de; 2014

Latin American Society of Biomaterials and Artificial Organs (SLABO)

Hydrogels are physically or chemically cross-linked polymer networks that are able to absorb large amounts of water. Hydrogels sensitive to external factors (pH, temperature, ionic forces, electric fields, etc.) constituting the so called ?smart hydrogels?. Smart hydrogels have been used in a wide range of biomedical applications including contact lenses, corneal implants, drug delivery, artificial meniscus and skin, ligaments, tendon, cartilage and bone substitutes. The aim of this work was to determine the adhesion of transgenic bovine fetal fibroblast (BFF) on surfaces based on PNIPAm (termosensitive polymer). Hydrogels were synthesized via free-radical polymerization of NIPAm (N-isopropyl acrylamide) and copolymerization of NIPAm with AMPS (2-acrylamido-2-methylpropanesulfonic acid) or HMA (N-[Tris(hydroxymethyl)methyl] acrylamide). BIS (N,N-methylenebisacrylamide) was used as crosslinker. APS (Ammonium persulfate) and TEMED (N,N,N?,N?-tetramethylenediamine) were used as the initiator system for polymerization. Hydrogel biocompatibility studies were performed with bovine fetal fibroblasts which expressed constitutively green fluorescent protein (GFP) to facilitate the microscopic visualization of cells. Gels were hydrated with complete cell culture medium (DMEM, 10% of bovine fetal serum and antibiotic-antimitotic) and placed in cell culture dishes. Fluorescent BFF were trypsinized and seeded on the surface of the different types of hydrogels. Interaction of BFF with the gel was microscopically evaluated at 24 h after seeding. Cell viability was determined by the MTT assay and compared with a control group without hydrogel. The synthesized hydrogels exhibited different phase transition temperatures (TPT) according to characteristics of dissolvent or culture medium (water or DMEM). For example, TPT of PNIPAm-co-20% HMA in water was around 42°C while in DMEM was less than 37°C. Also the swelling percentage of hydrogel decreased when the salt concentration in culture medium increased. Cell adhesion was higher in collapsed gels at 37°C (~50% for PNIPAm, PNIPAm-co-2% AMPS and PNIPAm-co-20% HMA) than that observed in swelled gels (~30%, PNIPAm-co-10% AMPS); possibly increasing the hydrophobicity of the gels stimulates better matrix-cell interaction. Morphology of BFF was normal and no microbiological contamination was detected. Viability of cells growing on different gel surfaces was not different from that in the control group. To improve cell adhesion, we suggest the incorporation of hydrophobic domains to the polymer matrix. These preliminary results suggest a possible application of these hydrogels in tissue scaffold or bioengineering.