RM+FSM+Independent+Preparation

First Semester Milestone Report Home

I have done a little independent preparation of samples, but it has always been monitored. I don't feel entirely comfortable with making the samples myself. I can clean mica surfaces (that's very basic) and deposit the solutions. With careful study and practice, I can surely overcome the other milestones. I have so far observed the other procedures and helped with the preparation; however, I have never made an entire solution alone. To clean the silicon wafers, you have to go into a cleaning room, where a special pass is required. Soon, I'll be receving one.

Cleaning mica surfaces is relatively simple. Mica is very much like graphite; therefore, all you need to do is peel off a layer of the surface using a piece of tape.
 * Describe how to clean mica surfaces.**

(These steps were taken from notes that AL gave me)
 * Describe how to clean silicon surfaces (the many steps, in order).**
 * 1) As always in a lab, wear a face shield, gloves, and an apron.
 * 2) Cut silicon wafers into 1 cm sqaured pieces with a diamond tipped pen.
 * 3) Use scotch tape to remove excess particles.
 * 4) Place chips and toluene into a beaker, and let it boil for 30 minutes under a fume hood. Place a watchglass on top (to remove the grease). Dispose the toluene in a non-halogen waste bottle.
 * 5) Rinse wafers with 18 mega ohm water after they've cooled. Dry with nitrogen gas.
 * 6) Add 20 mL of concentrated H2SO4 and 6-7 mL of 30% H2O2, together they yield "piranhic" acid, in a 50 mL beaker. This will destroy any organic molecules and reduce contaminants.
 * 7) Boil the dry wafers in the piranha acid and wait 15-30 minutes while they are at 90 degrees Celsius. Cover the beaker with a watchglass.
 * 8) Remove wafers using plastic tweezers. Rinse them thoroughly with dH2O. Dry them with nitrogen gas. Dispose of piranha acid in acide waste bottle. Make a record on the logbook.
 * 9) Move wafers to mos bench (clean room).
 * 10) Turn on the RCA 1 and RCA 2 baths and set the temperature to 70 degrees Celsius.
 * 11) Place wafers in strain basket and rinse with water for 2 cycles.
 * 12) Put wafers in basket, the HF for 20-30 seconds. This removes SiO2 layer.
 * 13) Rinse wafers again with water for 2 cycles.
 * 14) Place 100 mL of 30% H2O2 into CCA 1 and RCA 2 baths. This grows a new 1 nm thick layer on the wafers.
 * 15) Place wafers and tweezers into RCA 1 (NH4OH and H2O2) bath for 10 minutes. Turn on bubbles.
 * 16) Rinse wafers and tweezers for 2 cycles in distilled water.
 * 17) Place wafers and tweezers into RCA 2 (HCl and H2O2) bath for 10 minutes. Turn on bubbles.
 * 18) Rinse wafers for 2 cycles in H2O.
 * 19) Dry the wafers with nitrogen gas and store in a clean container.
 * 20) Turn off bubblers and heaters, and clean hands.

Materials: 18 mega ohm water, vial, silicon wafer(s) (cleaned), nitrogen gas, plastic containers.
 * Describe how to prepare a 1% and 0.1% APTES solution.**
 * 1) Dispense appropriate amounts of APTES and 18 mega ohm water into a clean vial.
 * 2) Place one wafer (silicon) in each vial.
 * 3) After 10 minutes, wash the wafer off with 18 mega ohm water and dry it with nitrogen gas.
 * 4) Place the wafers into clean plastic containers.

I don't have this process down, yet, but here's how AL explains it on the main AFM page. "I first take 5 uL (microliters) of the Kpn I restriction enzyme and mix with 10 uL of the buffer solution, 1 uL of a BSA solution and 5 uL of a 1ug/uL concentration, along with 79 uL of water for a 100 uL solution which is put into a tube. I then treat the mixture with chlorophorm, sodium acetate, and ethanol and put the tube in a centerfuge a number of times in a "cold room" at the lab. I can then store the mixture in a freezer for a period of time until I need it, which is after I clean my silicon samples. It is on //these// silicon wafers where I deposit the DNA mixture with the restriction enzyme."
 * Describe how to prepare the DNA plasmid solution.**

Silicon wafers- deposit a drop or two in the middle of the sample. Mica surfaces- deposit a drop (it really doesn't matter because it will spread across the surface).
 * Describe how to deposit solutions on the surface, and the difference between depositing on silicon and mica surfaces.**

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