Removing the top plate of the chip


#1

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young


#2

Hi Curtis,

Is there any reason you can’t just load blood samples onto the chip through the reservoirs? This is what we have done in the past. Note that you will need to add surfactant (we have used 0.1% Tetronic 90R4 successfully with blood). Diluted blood is also easier to move if this is a possibility.

Note that because blood has such a high protein content, it will eventually foul the surface (i.e., make it hydrophilic). I haven’t seen any convincing evidence that “washing” helps, but we haven’t explored this much. People have reported improvement after reflowing the Teflon/Fluoropel on a hot plate. I also assume that you could re-coat the Teflon/Fluoropel with a spin coater to restore the surface hydrophobicity.

-Ryan

···

On Mon, Sep 10, 2018 at 5:55 PM, curtis...@sjsu.edu wrote:

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young

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#3

Hi Ryan,

Thanks for the reply! We had been discounting actuating blood droplets as we’d though it would be too difficult. But it sounds like you have been able to create blood droplet specimens through the reservoir with added surfactant? Does this method make more sense than removing the top plate to dispense droplets?

We are looking at acquiring Fluoropel to re-coat, is there a recommended formulation?

Thanks!

Curtis

···

On Tuesday, September 11, 2018 at 1:34:24 PM UTC-7, Ryan Fobel wrote:

Hi Curtis,

Is there any reason you can’t just load blood samples onto the chip through the reservoirs? This is what we have done in the past. Note that you will need to add surfactant (we have used 0.1% Tetronic 90R4 successfully with blood). Diluted blood is also easier to move if this is a possibility.

Note that because blood has such a high protein content, it will eventually foul the surface (i.e., make it hydrophilic). I haven’t seen any convincing evidence that “washing” helps, but we haven’t explored this much. People have report improvement after reflowing the Teflon/Fluoropel on a hot plate. I also assume that you could re-coat the Teflon/Fluoropel with a spin coater to restore the surface hydrophobicity.

-Ryan

On Mon, Sep 10, 2018 at 5:55 PM, curt...@sjsu.edu wrote:

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young

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#4

Yes, I’d give it a try. This is the method we used in our Kenya field trial (note that this particular study used a 1:20 dilution of blood, but we have also moved whole blood + surfactant). I’m not sure what advantage you would gain by removing the top plate.

We typically use Fluoropel PFC 1101V or PFC 1601V (same fluoropolymer, but different solvent). They are available from https://www.cytonix.com

-Ryan

···

On Tue, Sep 11, 2018 at 7:06 PM, curtis...@sjsu.edu wrote:

Hi Ryan,

Thanks for the reply! We had been discounting actuating blood droplets as we’d though it would be too difficult. But it sounds like you have been able to create blood droplet specimens through the reservoir with added surfactant? Does this method make more sense than removing the top plate to dispense droplets?

We are looking at acquiring Fluoropel to re-coat, is there a recommended formulation?

Thanks!

Curtis

On Tuesday, September 11, 2018 at 1:34:24 PM UTC-7, Ryan Fobel wrote:

Hi Curtis,

Is there any reason you can’t just load blood samples onto the chip through the reservoirs? This is what we have done in the past. Note that you will need to add surfactant (we have used 0.1% Tetronic 90R4 successfully with blood). Diluted blood is also easier to move if this is a possibility.

Note that because blood has such a high protein content, it will eventually foul the surface (i.e., make it hydrophilic). I haven’t seen any convincing evidence that “washing” helps, but we haven’t explored this much. People have report improvement after reflowing the Teflon/Fluoropel on a hot plate. I also assume that you could re-coat the Teflon/Fluoropel with a spin coater to restore the surface hydrophobicity.

-Ryan

On Mon, Sep 10, 2018 at 5:55 PM, curt...@sjsu.edu wrote:

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young

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#5

Appreciate the information! The idea behind removing the top plate was to dispense blood specimens directly onto the middle of the chip without worrying about the difficulties of actuating blood. The specimens could then be mixed with other droplets generated from reservoirs as necessary. Thanks again for the replies!

Curtis

···

On Wednesday, September 12, 2018 at 11:40:31 AM UTC-7, Ryan Fobel wrote:

Yes, I’d give it a try. This is the method we used in our Kenya field trial (note that this particular study used a 1:20 dilution of blood, but we have also moved whole blood + surfactant). I’m not sure what advantage you would gain by removing the top plate.

We typically use Fluoropel PFC 1101V or PFC 1601V (same fluoropolymer, but different solvent). They are available from https://www.cytonix.com

-Ryan

On Tue, Sep 11, 2018 at 7:06 PM, curt...@sjsu.edu wrote:

Hi Ryan,

Thanks for the reply! We had been discounting actuating blood droplets as we’d though it would be too difficult. But it sounds like you have been able to create blood droplet specimens through the reservoir with added surfactant? Does this method make more sense than removing the top plate to dispense droplets?

We are looking at acquiring Fluoropel to re-coat, is there a recommended formulation?

Thanks!

Curtis

On Tuesday, September 11, 2018 at 1:34:24 PM UTC-7, Ryan Fobel wrote:

Hi Curtis,

Is there any reason you can’t just load blood samples onto the chip through the reservoirs? This is what we have done in the past. Note that you will need to add surfactant (we have used 0.1% Tetronic 90R4 successfully with blood). Diluted blood is also easier to move if this is a possibility.

Note that because blood has such a high protein content, it will eventually foul the surface (i.e., make it hydrophilic). I haven’t seen any convincing evidence that “washing” helps, but we haven’t explored this much. People have report improvement after reflowing the Teflon/Fluoropel on a hot plate. I also assume that you could re-coat the Teflon/Fluoropel with a spin coater to restore the surface hydrophobicity.

-Ryan

On Mon, Sep 10, 2018 at 5:55 PM, curt...@sjsu.edu wrote:

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young

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#6

Ok, that makes sense. Blood will certainly cause biofouling (i.e., protein adsorption to the surface) on any electrodes that it passes over, but if you do it quickly, you may be ok.

If necessary, you may also be able to remove/replace the top plate, but in that case, you’d probably want to experiment with a different assembly method since the tapes we use to attach the top plates will make this difficult.

-Ryan

···

On Wed, Sep 12, 2018 at 3:23 PM, curtis...@sjsu.edu wrote:

Appreciate the information! The idea behind removing the top plate was to dispense blood specimens directly onto the middle of the chip without worrying about the difficulties of actuating blood. The specimens could then be mixed with other droplets generated from reservoirs as necessary. Thanks again for the replies!
Curtis

On Wednesday, September 12, 2018 at 11:40:31 AM UTC-7, Ryan Fobel wrote:

Yes, I’d give it a try. This is the method we used in our Kenya field trial (note that this particular study used a 1:20 dilution of blood, but we have also moved whole blood + surfactant). I’m not sure what advantage you would gain by removing the top plate.

We typically use Fluoropel PFC 1101V or PFC 1601V (same fluoropolymer, but different solvent). They are available from https://www.cytonix.com

-Ryan

On Tue, Sep 11, 2018 at 7:06 PM, curt...@sjsu.edu wrote:

Hi Ryan,

Thanks for the reply! We had been discounting actuating blood droplets as we’d though it would be too difficult. But it sounds like you have been able to create blood droplet specimens through the reservoir with added surfactant? Does this method make more sense than removing the top plate to dispense droplets?

We are looking at acquiring Fluoropel to re-coat, is there a recommended formulation?

Thanks!

Curtis

On Tuesday, September 11, 2018 at 1:34:24 PM UTC-7, Ryan Fobel wrote:

Hi Curtis,

Is there any reason you can’t just load blood samples onto the chip through the reservoirs? This is what we have done in the past. Note that you will need to add surfactant (we have used 0.1% Tetronic 90R4 successfully with blood). Diluted blood is also easier to move if this is a possibility.

Note that because blood has such a high protein content, it will eventually foul the surface (i.e., make it hydrophilic). I haven’t seen any convincing evidence that “washing” helps, but we haven’t explored this much. People have report improvement after reflowing the Teflon/Fluoropel on a hot plate. I also assume that you could re-coat the Teflon/Fluoropel with a spin coater to restore the surface hydrophobicity.

-Ryan

On Mon, Sep 10, 2018 at 5:55 PM, curt...@sjsu.edu wrote:

Hello,

I’m a graduate student at SJSU working with Dr. Lee and Dr. Simon and using the DropBot! As we are looking to dispense blood samples directly onto the lower chip, is it possible to remove (and replace) the top plate? Furthermore, is there an appropriate way to clean the chip for reuse?

Thanks very much!

Curtis Young

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