EXPERIMENTS 1. Cell adhesion

Three experiments were designed to study the cell adhesion capability of the V79-4 cells.

3.1.1.. Exp. a1

Foils of PMMA, 150 Pm thickness were irradiated and reconditioned with the protein coating procedure and then inoculated with the V79-4 cells. There are two groups according to the radiation treatment.

Subgroup a1.1: irradiated with 10¹¹ ff/cm² Subgroup a1.2: irradiated with 3.10¹¹D/cm². 3.1.2. Exp. a2

Foils of PS, 150 Pm thickness were bombarded with 10¹¹ ff/cm²[2] and then inoculated with cells according to the cultivation procedures.

3.1.3. Exp. a3

Foils of PVDF, 25 Pm thickness were bombarded with ff with exposure time between 2 seconds and 600 seconds and etching times corresponding to track diameters between 1 and 9Pm [3]. Then cell inoculation according to the corresponding procedure.

3.2. Intelligent materials and grafted materials

Foils of polyethylene terephtalate (PET), cellulose triacetate (CTA) and polyvinylidene fluoride (PVDF) were used to obtain intelligent materials. PET, PVDF 14 Pm and CTA 20Pm foils were transformed to NTM by bombardment with ff and then etched to get a porous structure with determined porous size. PVDF foils, 25 Pm thickness, were grafted with NIPAAm, MMA, HEMA, AAc and styrene using 25 MeV protons particles from the CAE cyclotron accelerator and VP, MMA, HEMA, AAc and styrene using gamma rays from an extended Co-60 source.

Foils of CTA, 60 Pm thickness, were grafted with NIPAAm and with AAc monomers without ff bombardment. PET grafting was assayed under mutual and preirradiation grafting methods, while CTA and PVDF only by the preirradiation one.

3.2.1. PET soaked

Two experiments with PET 20 and 14 Pm respectively were performed searching etching conditions for different foil thickness:

3.2.2. PET 20 Pm, soaked

PET 20Pm thickness bombarded 5 s with ff were chemical etched with a 5N NaOH solution at 40^oC during 5h to obtain 3Pm diameter tracks. The NTM was soaked at room temperature in aqueous solution of 10% wt N-isopropylacrylamide (NIPAAm) monomer and irradiated at 60^oC under nitrogen atmosphere for 1 h with gamma rays from a cobalt source at a dose rate of 10kGy/h [5].

3.2.3. PET 14 Pm, soaked

PET- NTM filters 14 Pm thickness 1 h etch in 5N NaOH at 60^oC (3 Pm diameter).

Irradiation and grafting conditions as in the previous case.

3.2.4. PET 14Pm thickness, in solution

PET 14 Pm thickness, bombarded 5 s with ff were chemical etched with a 5N NaOH solution at 42^oC during 5h to obtain 3Pm diameter tracks. The NTM were washed and tested with phenolphthalein until the residual water did not tack, then NTM were washed again using boiling distillate water during an hour. After that NTM were put into test tubes with a solution of NIPAAm at concentrations between 0.1, 0.2, 0.5, 1 and 2.5% and irradiated with gamma rays from the cobalt source at 2.1 and 3.6 kGy.

3.2.5. PET 20Pm, preirradiated

PET 20Pm thickness bombarded 5 s with ff, chemical etched to obtain 5 Pm track diameter NTM were preirradiated by gamma rays from the cobalt source at a dose of 100 kGy and at dose rate of 0.178 kGy/h. After that, they were put into test tubes with aqueous solutions of NIPAAm at concentrations between 7% and 30%, in nitrogen ambient.

3.2.6. CTA, 27 Pm

Cellulose triacetate foils 27 Pm thickness were extracted in boiling toluene during 24 h and then preirradiated with gamma rays from the cobalt source at a dose of 100 kGy and put into a 6% NIPAAm solution in nitrogen ambient during 1 h at 62^oC.

3.2.7. CTA, 60 Pm

Cellulose triacetate foils 60 Pm thickness were preirradiated with gamma rays from the cobalt source at doses between 10 and 100 kGy and put into test tubes between 0 and 40%

acrylic acid solution and different Mohr salt concentrations in nitrogen ambient during 1 h at 62^oC [9]. These foils were also extracted in boiling toluene during 24 h.

Some CTA samples were chemically etched using 6.25 N KOH solution during 10 minutes at 60^ºC.

3.2.8. CTA, 20 and 40 Pm

CTA films from pellets, Aldrich Chemical Company, Inc., were prepared by dissolution in diclorometano and evaporation, 20 and 40 Pm thickness. CTA foils were irradiated between 10 s and 60 s with ff, etched chemically using a 6.25 N KOH solution at 62^oC during different etching times to produce tracks with diameters between 1.5 Pm and 8 Pm. The foils were washed with distillate water during 24 hour at room temperature and dried in vacuum during a day at 40 ^oC. After that, irradiated with gamma rays from the cobalt source at between 5 and 60 kGy at a rate of 0.179 kGy/min in pure oxygen ambient to produce peroxides. The foils were put into closed test tubes with aqueous solutions of AA of 15%, bubbled in nitrogen ambient and put into the warming bath at 62^oC.

3.2.9. PVDF 14Pm

PVDF foils, extracted in boiling toluene 24 h were irradiated between 1 s and 330 s with ff, etched chemically using a 6N KOH + 0.1 F KMnO4 solution at 85^oC during different etching times to produce tracks with diameters between 0.5 Pm and 6Pm. The foils were washed with distillate water and put in an oxygenated water solution of chloridric acid during an hour at room temperature, then washed in distillate water and dried in vacuum during a day at 40 ^oC. After that, irradiated with gamma rays from the cobalt source at between 10 and 140 kGy at a rate of 0.179 kGy/min in pure oxygen ambient to produce peroxides. The foils were put into closed test tubes with aqueous solutions of NIPAAm between 0% and 16% or acetone solutions of NIPAAm between 0% and 40%, bubbled with nitrogen and put into warming bath at 62 ^oC or 80 ^oC during grafting times between 0 and 15 h and 18 min.

PVDF-NTM, 20 sec. ff irradiation time, 3Pm pore diameter, were irradiated with gamma rays from the cobalt source at between 10 and 100 kGy at a rate of 0.179 kGy/min in pure oxygen ambient. The foils were put into closed test tubes with aqueous solution of AAc (15%) or with VP.

3.2.10. PVDF 25Pm

PVDF foils were irradiated with gamma rays from the cobalt source at between 10 and 100 kGy at a rate of 0.179 kGy/min in pure oxygen ambient to produce peroxides. The foils were put into closed test tubes with styrene, HEMA, MMA, VP and aqueous solutions of AAc (15%), bubbled in nitrogen ambient and put into the warming bath at 62^oC.

3.2.11. PVDF 25Pm

PVDF foils were irradiated with 25 MeV proton particles from the cyclotron CAE accelerator between 9.2 and 276 kGy at a rate of 69 kGy/min in air ambient to produce peroxides. The foils were put into closed test tubes with styrene, HEMA, MMA, and aqueous solutions of AAc (15%) or NIPAAm (10%), bubbled in nitrogen ambient and put into the warming bath at 62^oC.

3.2.12. PVDF 25 Pm

PVDF films, 25 Pm thickness were irradiated with:

(1) Fission fragments with doses between 0,3 and 200 kGy (2) Alpha particles with doses from 3 to 50 kGy.

Samples i) and ii) were grafted with styrene between 0 and 22 h at 62^oC. Same procedure as above.

3.2.13. PC-NTM and PC foils

Makrofol E (Bayer AG) foils of 10 Pm thickness and 5 Pm pore diameter Micron Separation inc. filters (NTM) were grafted with HEMA. Thin polycarbonate (PC) foils and NTM, were grafted with hidroxyethylmethacrylate (HEMA) using gamma photons and the simultaneous method. Pc foils were cleaned with destiled water and 2% Extran MAO2 neutral Merck for one day, thoroughly washed in destiled water for ten days and then dried in air for a month. NTM were used as received.

4. RESULTS