Porous Silicon Microparticles for Delivery of siRNA Therapeutics

The overall goal of the following experiment is to assemble and characterize a small interfering RNA or SI RNA delivery system. This is achieved by grafting porous silicone microparticles with polyethaline and arginine to create a platform with a cation charge. As a second step, irna molecules are mixed with the microparticles, which results in irna binding.

Next arginine polyethaline siRNA nanoparticles will be formed as the silicon gradually degrades in order to enable sustained release of the IRNA. This technique could have implication for the treatment of virus diseases. It enables the efficient delivery of small interfering RA First oxidized non functionalized porous silicon particles in a 30%solution of hydrogen peroxide at 95 degrees Celsius for two hours.

When finished, emanate the oxidized particles in a 2%three amino propyl trixi silene solution in isopropyl alcohol for two days at 65 degrees Celsius with gentle stirring. Transfer the particles to a centrifuge tube and centrifuge the solution for 30 minutes at 18, 800 times. G.Following centrifugation Resus, suspend the pellet in isopropyl alcohol using brief sunation.

After repeating the centrifugation and washing step with isopropyl alcohol and ethanol, leave the particles in ethanol until ready to use. Next, add 10 microliters of particle suspension to 10 milliliters of isotone diluent, and count the particles with a particle counting analyzer. To determine the concentration of particles in the stock solution, activate the acid group of L-arginine with EDC and NHS by adding 0.1 nm of each to 20 milliliters of ethanol.

Gently stir the solution for two hours at room temperature using a magnetic stir plate. After briefly sonic the previously prepared particle stock solution. Add 1 billion particles to the L-arginine solution, leaving the reaction for 18 hours at room temperature with gentle stirring.

Following this, activate the first spartic acid group of n turt, but carbonyl l spartic acid with EDC and NHS by adding 0.1 mol of each to 20 milliliters of ethanol. Gently stir the solution with a magnetic stir bar for four hours in a cold room. After four hours of stirring, add a previously prepared polyethaline solution in ethanol to the spartic acid mixture.

Allow the reaction to proceed for 24 hours at room temperature with gentle stirring. At this point, activate the second Sephardic acid group of the solution with 0.1 M of EGC and NHS at four degrees Celsius for six hours with gentle stirring. To obtain poly functionalized, porous silicon or PCPS particles, add the previously prepared particle solution into the reaction mixture, allowing the reaction to proceed for 18 hours at room temperature with gentle stirring.

When finished, centrifuge the solution for 30 minutes at 18, 800 times G.Then wash the particle solution three times with ethanol using brief sonication to suspend the pellet to measure the size of the particles. Place a drop of the particle suspension on a clean silica scanning electron microscope or SEM sample stub and let dry at room temperature in a vacuum chamber once the sample is dry, measure SEM images at eight kilovolts with a three to five millimeter working distance using an inlands detector for measuring the zeta potential of the particles. Mix 10 microliters of particle suspension with one milliliter of 10 millimolar phosphate buffer in a 1.5 milliliter micro tube.

Then load the sample into folded capillary cells and measure the zeta potential according to the manufacturer's instructions. After drying the PCPS particles under vacuum overnight, add four micrograms of SIR a in 20 microliters of nuclease free water to the dried particles and sonicate. Briefly incubate the samples for three hours on a shaker in a cold room to allow I a binding to the particles following incubation, add four microliters of six XDNA loading dye to 20 microliters of the PCPS Control siRNA particles with different particle to siRNA ratios.

Then load the samples into a 2%arose gel containing DNA gel stain. Perform electrophoresis at a constant voltage of 120 volts for 20 minutes. In running buffer.

Analyze the gel with image acquisition and analysis software. At this point. Mix 20 microliters of the PCPS controls irna particle samples with two microliters of sodium ESAL sulfate.

After allowing the samples to stand for one hour at room temperature, add four microliters of six XDNA loading dye to them. Load the samples into a 2%aros gel containing DNA gel stain. Perform electrophoresis at a constant voltage of 120 volts for 20 minutes in running buffer, using DNA electrophoresis equipment and a power supply.

Finally, analyze the gel with image acquisition and analysis. Software SEM results reveal cylindrical PCPS particles with a 2.6 micrometer diameter. The particles are positively charged with a zeta potential of approximately plus 8.21, thereby enabling electrostatic binding with negatively charged nucleotides.

Confocal images of the PCPS particles demonstrate that fluorescent control irna is loaded inside the porous silicon particles. The size distribution of the arginine irna nanoparticles released from the porous silicon microparticles ranged from 70 to 120 nanometers. Atomic force microscopy images illustrates spherical nanoparticles.

The particle to irna ratio was optimized by aros gel electrophoresis to ensure high binding affinity. The results indicate that sir, a can bind tightly to the particles when the amount is above eight times 10 to the fifth. Furthermore, siRNA was successfully released when treated with sodium ESOL sulfate.

Confocal images taken after 24 hours of treatment show that the particles are effectively internalized into cells. Similarly, 89%have internalized particles after 24 hours of incubation. Moreover, the internalization process was recorded for 12 hours indicating that the PCPS particles can efficiently deliver SIRA into cells.

The long-term accumulation of SIR A inside the cells was also evaluated by confocal microscopy. And sir A was still detectable at day seven and 10. After watching this video, you should have a good understanding of how to sensible and characterize A SNA delivery system based on Poly America Silicon microparticles.