The overall goal of this procedure is to fabricate mechanically tunable and bioactive metal scaffolds for biomedical applications. This method can help answer key questions in the orthopedic implant field, such as the feasibility of a mechanical tuneable metal scaffold that is capable of delivering drugs. This gentrification method is simple because it requires only one control.
Parameters achieve both mechanical enhancement and the sustainable drug release and is capable to the fabrication of functionality created por oid First mix the appropriate amounts of titanium powder, caffeine, and KD four for porous titanium scaffolds with four initial porosities in 500 milliliter polyethylene bottles. Rotate the bottles in a ball mill oven at a speed of 30 RPM at 55 degrees Celsius for 30 minutes. Pour the slurries from the polyethylene bottles into cylindrical aluminum molds with a diameter and height of 60 millimeters.
After sealing each aluminum mold with an aluminum cover slip, rotate the molds in a ball mill oven at a speed of 30 RPM at 55 degrees Celsius for 10 minutes. Subsequently, decrease the temperature of the ball mill oven to 44 degrees Celsius and continuously rotate the molds at a speed of 30 RPM at 44 degrees Celsius for 12 hours. After cooling the molds by rotation at room temperature for one hour, remove them from the ball mill oven.
Then remove the solidified titanium caffeine green body from each aluminum mold using an aluminum plunger. Following this. Place the solidified titanium caffeine green body in a rubber bag and completely seal the bag by tying it with a string.
Place the rubber bag in a water tank of a cold isostatic pressing machine and apply an isostatic pressure of 200 megapascals for 10 minutes. After removing the rubber bag from the machine, remove the compressed green body from the rubber bag. Transfer the titanium caffeine green body to an Illumina crucible.
Place the crucible in a freeze dryer machine and freeze dry the green body to sublimate the caffeine phase at minus 40 degrees Celsius for 24 hours. Following freeze drying, close the crucible with an Illumina cover slip. Place the closed crucible in a vacuum furnace at room temperature.
Then increase the temperature of the furnace to 1300 degrees Celsius at a heating rate of five degrees Celsius per Minute. Air dried green body samples are usually weak and may collapse. Extra care is needed during handling.
After holding the temperature at 1300 degrees Celsius for two hours, keep the centered porous titanium in the furnace for six to seven hours until the furnace is fully cooled to room temperature. Once the samples have been removed from the furnace, machine samples for smaller specimens, transfer samples to a glass beaker. Place the beaker in an autoclave and sterilize the samples at 121 degrees Celsius for 15 minutes.
When finished, wash the sterilized samples twice with distilled water and twice with 70%ethanol. Then place the porous titanium into a Petri dish and air dry the samples at room temperature under UV light. At this point, dilute green fluorescence protein or GFP to 100 micrograms per milliliter by mixing one milliliter with nine milliliters of ECCOs phosphate buffered saline solution In a 50 milliliter sterilized polystyrene tube, immerse the porous titanium in the diluted GFP solution at room temperature.
Then immediately place the sample in a vacuum desiccate and evacuate the desiccate for 10 minutes. To ensure the GFP solution penetrates the pores of the porous titanium more effectively remove the glass beaker from the desiccate. Then remove the porous titanium from the glass beaker using tweezers.
Place the GFP coated porous titanium into a 10 centimeter diameter Petri dish and air dry overnight at room temperature on a clean bench on the following day, rinse the porous titanium twice with 10 milliliters of ECCOs phosphate buffered saline in a glass speaker. Then place the porous titanium into a 10 centimeter diameter Petri dish using tweezers and air dry overnight at room temperature on a clean bench. Next place the GFP coated porous titanium samples with various heights in a cylindrical steel dye, and insert a set of punches into the top and bottom holes of the steel dye.
Compress the porous titanium within the steel dye assembly at room temperature in the Z direction of the sample. Using a press machine at intermediate strain rates of 0.05 to 0.1 inverse seconds against the predetermined applied strains. Hold the pressure for one minute.
Remove the dye from the press machine. Place the steel ring over the bottom of the dye body and return the dye to the press. After inverting the dye, slowly apply pressure until the plunger pushes the densified samples out of the D bore and remove the dye from the press.
Remove the densified titanium samples from the steel dye. Finally wash the densified samples twice with 10 milliliters of ECCOs phosphate buffered saline in a beaker and air dry overnight at room temperature on a clean bench. The titanium pore structure from conventional freeze casting shows directional pore alignment with irregularly shaped pores because of the dendritic growth of caffeine.
During freezing the sample from dynamic freeze casting exhibits almost spherical pores with random pore distribution, the pore shape becomes flattened as the degree of densification increases and pores almost disappear at the highest densification because neighboring pores are in contact with each other. Four specimens with varying porosities show different initial heights before densification and almost identical heights after densification. Both dents and porous titanium were found to have fast GFP release behavior with an initial bursting effect with most released within one week.
Densified porous titanium shows continuous release up to one month clearly showing GFP on the surface even after one month. For the scaffold with a denser core, the outer part was shortened by mechanical machining. The micro CT image after selective densification of the higher inner part shows the inner and outer parts of the scaffold with different porosities porous titanium with higher outer and lower inner parts results in a denser outer part after densification in which the porosity of the outer part was lowered with the inner part, having the preserved initial porosity Once mastered.
This technique can be done in 72 hours if it is performed properly after a development. This technique paved a way for researchers in the field of biomaterial to explore the feasibility of fabricating meta ology with the turnover mechanical properties and the drug related for treating spinal injuries. The implications of this technique extended toward the spinal injury therapy because the produce scaffold can act as artificial disc replacement with the drug delivery.
