Editing Calcium phosphate transfection protocol

1. Grow 293 cells in DMEM + 10% FCS + Pen/Strep at 37°C and 5% CO2 (split 1/10 every 2 days) 

2. Split cells to about 50% confluency at least 2 hrs prior to transfection. 

Cells must be low passage &amp; do not allow them to be over-confluent (max 60%). 

Incubate plates at 37oC overnight. If cell is 50~70% confluency after plating, you can do transfection in the morning. 

Overgrown cells should not be used for Ca transfection. 

3. Thaw 2X HBS at room temperature. Do not refreeze HBS after use. 

4. Prepare CaCl2/HBS/DNA nanoparticles (10 cm dish) 

aliquot '''0.5''' ml 2X HBS into a sterile 1.5 ml microfuge tube 

In a separate tube: 

Add X ÎŒl of ddH20 to the tube (final vol is 0.5 ml) 

Add 15 ÎŒg of lentivirus vector with GOI 

Add 15 ÎŒg of 3:1 pGag-Pol/pVSVG 

Add 50 ÎŒl of 2.5 M CaCl2 <br> 

<br> 

Add 500 ÎŒl of 2x HBSS to CaCl2/DNA mix, mixing gently during the addition. 

Incubate at RT for 20 min. 

Add mixture to cells by dropping slowly and evenly into medium, swirl plate gently. 

Incubate at 37°C/5% CO2 for overnight 

'''Note:''' 2x 10cm plates (when concentrated down to 100 ÎŒl), should give titres around 10<sup>9</sup>-10<sup>10</sup> <br> 

<u>'''For 150 mm Dish'''</u> 

30 ug DNA 

160 ul 2 M CaCl2 

1.3 ml 2XHBS 

<br> 

5. Remove media and add 10 ml fresh medium 

<br> 

'''2X HBS'''

8g NaCl 

0.2 g Na2HPO4-7H2O (0.14 g if using dihydrate; [phosphate] must be 1.5 mM) 

6.5 g HEPES 

pH to 7.0 and bring up to 500 ml with distilled water. Re-pH at this point because it can change. Aliquot and store at 20°C. 

or 

'''2X HBS 500 ml'''

HEPES (Acid) 5g 

NaCl 8g 

Dextrose 1g 

KCl 3.7g 

Na2HPO4(7H2O) 10ml of Na2HPO4(7H2O) *Stock Solution (see below) 

- Add ultrapure H2O up to ca. 450ml 

- Adjust pH to exactly 7.1 

- Add ultrapure H2O up to 1L 

- Filter through a 0.2u sterile filter 

Aliquot into sterile tubes and keep frozen at 20 oC. Keep one working tube at 4oC. 

'''Note:''' once thawed, do not re-freeze 

*Na2HPO4(7H2O) Stock Solution = 0.94 g of Na2HPO4(7H2O) in 50ml ultrapure H2O (Aldrich

Cat#32,007-2). 



'''<br>'''

'''2.5M CaCl2 100ml'''

CaCl2 27.75g anhydrous CaCl2

Or CaCl2 36.75g CaCl2(2H2O) <br>

Add water to 100 ml, filter sterilize and store at&nbsp;aliquot into 1.5 ml tubes, store at 4 °C or - 20 oC.<br>
<br>
This table is from another protocol, for reference only, do not use-- 

<br> 

{| cellpadding="0" border="0" style="height: 307px; width: 703px;"
|-
| width="64" height="20" style="height: 15pt; width: 48pt;" | Format 
| width="114" style="width: 86pt;" | Relative<span style="">&nbsp;
</span>Surface Area<span style="">&nbsp;
 
</span> 
| width="64" style="width: 48pt;" | Culture media 
| width="64" style="width: 48pt;" | Transf. Media 
| width="64" style="width: 48pt;" | 2X HBS 
| width="64" style="width: 48pt;" | 2.5M CaCl2 
| width="64" style="width: 48pt;" | Total DNA 
| width="64" style="width: 48pt;" | GFP
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 24 well 
| 0.25X 
| 500µl 
| 280µl 
| 18µl 
| 1.1µl 
| 1.1µg 
| 3.6-9.0ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 12 well 
| 0.5X 
| 1ml 
| 570µl 
| 36µl 
| 2.1µl 
| 2.1µg 
| 7.1-18ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 6 well 
| 1.2X 
| 2ml 
| 1.4ml 
| 86µl 
| 5.1µl 
| 5.1µg 
| 17-43ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 35mm 
| 1.0X 
| 2ml 
| 1.15ml 
| 71µl 
| 4.3µl 
| 4.3µg 
| 14-36ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 60mm 
| 2.6X 
| 5ml 
| 3ml 
| 186µl 
| 11µl 
| 11µg 
| 37-93µg
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | 10cm 
| 7X 
| 10ml 
| 8ml 
| 500µl 
| 30µl 
| 30µg 
| 100-250ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | T25 
| 3X 
| 5ml 
| 3.4ml 
| 214µl 
| 13µl 
| 13µg 
| 43-107ng
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | T75 
| 9X 
| 12ml 
| 10ml 
| 643µl 
| 39µl 
| 39µg 
| 128-321
|- style="height: 15pt;"
| height="20" style="height: 15pt;" | T150 
| 18X 
| 24ml 
| 20.5ml 
| 1.3ml 
| 77µl 
| 77µg 
| 258-643
|}



'''Day 3) Check transfections: '''<br>

- Cells should be reaching full confluency <br>

- Check fluorescence (if plasmid has a fluorescent tag) <br>

- Transfection efficiency should be around 90% <br>

Note: when you convert from âbright lightâ to âfluorescenceâ you should be able to see that approximately 90% of cells are positive for fluorescence. <br>

- Remove media <br>

- Add 10 ml of fresh DMEM + 2% FBS to each dish - Incubate overnight at 37°C/5% CO2 

'''Day 4) '''<br>

Viral Harvest # 1: <br>

- Collect &amp; pool supernatants (if you have multiple plates per vector) <br>

- Spin at 1500 rpm for 5 min to pellet any cells/cellular debris <br>

- Collect supernantant with a syringe &amp; filter through a 0.45 ÎŒm syringe filter into a âNEWâ pre-labelled falcon tube <br>

- Cover falcon tube containing filtered virus supernatant with parafilm &amp; place into sealable bag (double containment) <br>

- Store at 4oC overnight in a cardboard box <br>

- Add 10 ml of fresh DMEM + 2% FBS to each dish <br>

- Transfer to 37°C/10% CO2 incubator - Incubate overnight 

'''Day 5) Viral Harvest # 2: '''<br>

- Collect &amp; pool supernatants (if you have multiple plates per vector) <br>

- Spin at 1500 rpm for 5 min to pellet any cells/cellular debris <br>

- Collect supernantant with a syringe <br>

- Pass supernatant through a 0.45 ÎŒm syringe filter into the falcon tube containing your filtered âViral Harvest # 1â supernatant from the previous day <br>

<br>

Note: The cleared supernatant may be used to directly transduce cells &amp; titre will be relatively low (~106 viral particles/ml) 

'''Day 5) Virus concentration (for in vitro grade stock): '''<br>

- Centrifuge the supernatant using conical tubes and a Beckman ultracentrifuge with a SW41 swing bucket rotor (makes it easier to detect the viral pellet) <br>

- spin at 24,000 rpm for 1 hr at 4°C <br>

- carefully poor off supernatant without disrupting viral pellet <br>

- add last remaining supernatant &amp; spin again (do not use these tubes more than 3 times) <br>

- carefully poor off supernatant <br>

- allow remaining supernatant to drain off by resting tubes on paper towel <br>

- aspirate all remaining fluid <br>

- Resuspend viral pellet in 100 ÎŒl of 1x HBSS (no frothing) <br>

- Rinse tubes with 50 ÎŒl of 1x HBSS &amp; pool the samples (total volume per tube = 150 ÎŒl) <br>

- Transfer to âscrew-topâ microcentrifuge tubes or eppendorf tubes covered with parafilm <br>

- Vortex at low speed for 15-30 min <br>

- Spin 10 seconds using a table top microcentrifuge <br>

- Collect supernatant (140 ÎŒl). 

'''Note: '''<br>

Use 40 ÎŒl (max) to determine viral titres by FACS or p24 ELISA.<br>

Customers get 100 ÎŒl Short term storage (&lt; 1 mth) at -20°C; Long term storage (&gt; 1 mth) &amp; at -70°C. 

[[Category:Protocols]]