I think you could choose any material that is suitable for your needs.

the more important step would be to adjust the printing process to your material. There are several systems and procedures on the market.

Thank you for your input. However, I've been seeking to know whether hydrogels from natural polymers likes chitosan, alginate etc.  as a bio-ink fulfill the criteria of being easily handled while printing and is ideally optimized for tissue engineering purpose like a prosthetic or organ supporting device. I guess, physicochemical property define the feasibility and with what ease the printing comes out although several techniques and system are available out there. 

Hi Sandeep,

You bring an interesting question which I hope will spark some sort of debate.

To put in my two cents - The simple answer is look for the polymer most used in other processes for making scaffolds and try to create a system for bioprinting out of that material. These polymers will be non-toxic, with non-toxic degradation products (usually), often water soluble and may or may not be metabolized by the body (or fragmented and encapsulated). The mechanical properties will depend on the type of scaffold.

The less simple answer will be - It depends on the printing system you have available, the post treatments the scaffold may need to go to, the cells seeded on it, the geometry and many other conditions. 

Consider the following as well: Most 3D printing processes involve a phase-change (from fluid to solid via cooling a molten phase, crosslinking, sintering etc.). The mechanism to induce that phase change may limit the material used. The same mechanism dictates the resolution and possible geometry and "ink" preparation.

To address the use of alginate, chitosan and the other usual suspects (gelatin, other polysaccharides) - see the attached review, it will get you started. 

Good luck,

Eliad

http://dx.doi.org/10.1016/j.progpolymsci.2011.11.007

I've used plant-based bioplastic filaments for 3D printing on a Makerbot. The results were difficult to predict because the plastic was more prone to warp and less stable. The Makerbot itself is the worse partner for bioplastic filaments. I suggest a higher quality 3D printer like FormOne or one built from scratch. 

I have started to use medical grade TPU filament to print with Ultimaker 2. Results are hard to predict. I'm actually using 0.15mm nozzle.

The trouble  with smaller nozzle is that trying to build layers are difficult. The extrusion is very fine and infill print is pretty accurate as well.

@ Saman Naghieh. Yeah, can't argue more. In case of the natural polymers, fabricating by extrusion method seems to the best imprinting method as one can get. Hydrogels preparation can be adjusted by several factor for modifying it's mechanical and chemical properties. For instance, hydrogels acquire the thixotropic property i.e gel-sol transformation could be possible controlled by external agent such as temperature or pH or cross-linking agent during 3D printing with incorporation of cells or ECM of interest. Even we can imprint it as a liquid if it can hold the cells with adequate mechanical strength. By playing with the available parameter of printer like nozzle size, rate of flow etc. I reckon, we would be able to produce 3D imprint of desirable features. Furthermore, polymers in different forms like beads, polymeric gel, gel tubes etc. could be employed for embedding the cells, tissue of interest. Selecting natural polymers like alginate or chitosan, having the ideal properties of non-toxic, biodegradable, hydrophillic with high porosity, high surface area etc. can turn out to be a boon in regenerative medicine.

@ Eliad Cohen, Thank you very much for giving your insights. It was really the type of feedback that I was looking at. Your information was really beneficial for getting more ideas. 

hey! you should check out buildwithlife.com ! has some great suggestions for materials for 3D printing and protocol references!