Laser intensity variation - Tissue engineering application

Hi all,

I am new here but am looking for some clarification on the laser used in the F1 / F1+ and the possibility to vary its intensity. My apologise if this is in the wrong place, please direct me to the best place in the forum if here is no good.

I have seen other post about varying the laser intensity on the feature request channel and I wanted to clarify if it is indeed possible with the Form1 hardware. Would it simply be a cause of adjusting the current to the laser to change the intensity level?

The reason I ask is we are just beginning to use the F1 for a tissue engineering application using a speciality photo-initiated polymer. The intensity of the UV light used in this application directly correlates to the stiffness of the material. To be able to vary the intensity of light we could achieve stiffness gradients throughout our constructs - a highly desirable feature.

If the hardware is capable, how “hackable” is the Form1? This is a feature we would very much request, however I imagine it will take time for the Formlabs team to put together. Is there capability for hackers/tinkerers and in this case engineers to utilise the hardware of the F1 and create our own scripts?

Thanks for any comments / advice you can give.

Regards, A SLA newbie.

This is the perfect place to ask your question, and I’m happy to help answer!

The laser intensity - both speed and power - is dictated by the material settings for each resin and layer height. Because Formlabs designs and tests print settings for each of our own resins, these configurations are built into the PreForm software and the settings are not displayed or adjustable by users. The existing material settings (and thus the programmed laser settings) are the only current options available.

The Form 1+ isn’t quite designed to be “hacked” in the way you described. If you wanted to use a third-party polymer, it would need to be curable with an existing setting for a Formlabs resin.

I’m curious to hear more about your tissue engineering. What’s the nature of the material you need? Perhaps if there’s not something useful in an existing Formlabs resin, we’re always working on testing and development to improve resin formulations.

Long story short, they do not think your use case is valid so will not support it no matter how reasonable it may seem or how possible it is. They can and do adjust the power to the laser, there is no hardware limitation preventing it, they just do not, and will not, support anything third party. This includes software or materials.


Thanks Stephen, this is useful to know.

We are using Gelatin methacrylate (GelMA) a cell friendly hyrdogel. Currently we include the photo initiator Irgacure 2959, or IC2959 at a concentration of 0.05% (w/v).

This combination is placed in mold and exposed to 2.5 mW/cm2 at 365nm. The time can vary depending on the concentration of the photo-initiator. Higher concentration, less time needed. Additionally a higher intensity would mean less time required. However, our current method only allows for a fixed intensity.

This process produces small cube like hydrogels. By moving to a SLA print we can produce intricate structures with micrometer detail. This is not original, many types of hydrogels have been printed using SLA technology. We hope to do it using easily accessible, consumer grade printers like the Form1.

Are you able to share the parameters used in the PreForm settings? Or what the wavelength of the UV light is? If it is higher/lower than 365nm, we can potentially use a different photoinitiator molecule which absorbs at a different wavelength. However, if it too low, 280-260nm DNA and proteins absorb this light and it can cause cytotoxicity and damage our cells.

These details could allow us to select the best profile to use in PreForm and hopefully see us printing hyrogels for tissue engineering on the Form1.

My group specifically works on engineering cartilage tissue, One of the features of this tissue is that it has a varying stiffness moving from the bone outwards. If we could varying the intensity of the laser through a single print, we could include a stiffness gradient in our hydrogel and produce structures which better replicate true cartilage tissue. This is why I asked my original question on weather you could vary the intensity. If we could write a script to enable intensity variation in a single print with the Form1 it would have incredible benefits for our research,

Thank you for getting back to me Stephen, any information you could give us would be really helpful. :relaxed:

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You’re very welcome, Erin. The laser in the Form 1+ uses 405 nm wavelength, so it sounds fairly close to the wavelength you need. We don’t have a way to vary the laser intensity with a custom script, but I’ll still do some more digging to see whether there’s any other information we can share that will better enable you to print the hydrogel. Sounds like a neat research application, and I’m so glad you shared it here!

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