Dear Juliana

Great Question.

As Yang has said, porosity depends on the fabrication and selected materials and their large influence... From my recent experience for one of my customer on making the bobbins, (which is cigarettes outer cover of paper, before stuffing tobacco) porosity is the factor that decides the quality customer experiences, which is largely influenced by pulp, water content, sequezing pressure influencing grain structure etc results in porosity... What we did was to take thro DFSS (design for Six Sigma) approach to freeze the spec on porosity and control spec for significant factors.

Suggest arrive at your spec on porosity that has the best effect on output of the product.

Have great research delivery, surely be with few Innovations

Kindest Regards

Ramanan

Dear Juliana

Great Question.

As Yang has said, porosity depends on the fabrication and selected materials and their large influence... From my recent experience for one of my customer on making the bobbins, (which is cigarettes outer cover of paper, before stuffing tobacco) porosity is the factor that decides the quality customer experiences, which is largely influenced by pulp, water content, sequezing pressure influencing grain structure etc results in porosity... What we did was to take thro DFSS (design for Six Sigma) approach to freeze the spec on porosity and control spec for significant factors.

Suggest arrive at your spec on porosity that has the best effect on output of the product.

Have great research delivery, surely be with few Innovations

Kindest Regards

Ramanan

The higher the porosity the better, just make sure the mechanical properties of the TE construct are still in a reasonable range (look at the strength of bone for a threshold). In practice this usually comes down to the porosity range stated by Miroslav and Yang: somewhere between 60 en 90%.

I agree with some the other replies and would like to add that high porosity alone is not sufficient; for tissue ingrowth one requires not only sufficient porosity, but also large enough pores and interconnectivity between the pores. See attachment for some introductory information and methods. Kind regards. Deon.

Porosity can be defined in numerous ways, percent porous, pore diameter, interconnectivity are some examples. Something that is 60% porous may not work as a bone material if its average pore size is less than 100 microns diameter (needed for osteoclast proliferation). Even then, porosity in bone is variable - cortical bone having approx. 10% with pores in the 200 micron range and trabecular being in >60% with pores ranging from 250 microns to 7000 microns. Therfore, one will also need to define the specific porosity associated with the tissue as well as its anatomic location/function. Craniofacial bone is not similar to long bone, for example.

Article Effect of nitinol implant porosity on cranial bone ingrowth ...

Another porosity example.

Article Quantification of Bone Ingrowth into Porous Block Hydroxyapa...

I agree with all the very helpful answers.  Porosity and pore size indeed come hand in hand because it is important that the cells can infiltrate the scaffold and thus grow and proliferate there.  Regarding the degree of high porosity, it may useful to quantify cell viability in the scaffold to make a judgement if porosity is enough.  Ultimately, the goal is to match the native tissue's properties, and so we should aim for appropriate porosity rather than just high porosity.