Dear Nisha

If you tried sterilization using gamma irradiation or ethylene oxide, the gel forming ability of the pre-gel solution will be inhibited. That may be due to the degradation of the sensitive protein fibers, so may not be able to form hydrogel, especially at the sterilizing doses of the gamma irradiation. This may be also combined with a change in the surface and mechanical properties of the hydrogel, if formed. Moreover, the electron beam sterilization can alter the structural properties of these sensitive biopolymers. You can check this paper:

http://www.sciencedirect.com/science/article/pii/S175161611200255X?via%3Dihub

However, in some current research papers, the usage of supercritical CO2 has gained the attention as a sterilizing method for the pre-gel solution which can maintain its gel-forming ability. These papers may help you:

http://www.frontiersin.org/10.3389/conf.fbioe.2016.01.00032/event_abstract

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466598/

Regards

Thank you so much. It is very helpful

Hi!

It'll be better if You use stiryl components for collagen gel forming since if you make fick layer of the gel it will be difficult to sterilize it. Growth factors solutions could be sterilized using antibacterial filters and since collagen is dissolved in acetic acid solution it is steryl (add steryluzed medium or buffer). If all growth factors are in the deep layers of the gel You can apply UV radiation. Other case is pasterization if You have appropriable equipment.

Regards,

Tatiana

Hi Nisha,

in principle the "softest" way is UV if indeed the growth factors are deep in the layer, but this method of sterilization is often not accepted and not that effective. On the other hand there are gamma ray and ethylene oxide: the first one is very effective as much as harmful for your growth factors; the latter sounds to me the best one. My suggestion is prepare some samples sterilize them and perform an analysis on the growth factors presence and activity.

Good luck!

Andrea

Hi Nisha

The sterilization of scaffolds with growth factor has always been an issue. the major things that you can try out are

1. prepare the collagen hydrogel in a sterile environment, i.e within a clean hood and add GF 

2. UV sterilization can also be done 

3. ETO sterilization. I had actually compared the effect of ETO sterilization on my scaffolds containing platelet rich plasma. When PRP as such was ETOd i could observe a decrease in growth factor activity. however when the PRP was incorporated in my scaffold and then ETOd, I found the activity was not affected.

However ETO sterilization may change your hydrogel property.

So it would be best to try out the different techniques and ensure that growth factor activity is mot lost as well as your hydrogel properties are not compromised. 

@ Andrea  Thanks for the suggestion.

In the case of UV sterilization how long the exposure should be?

Like already mentioned by few people, I do aseptic handling procedures. I handle all the components under a sterile bio-safety cabinet.

We usually sterilize collagen gels up to 0.5 mL under UV light in the laminar (30 min), which works very nice. All the best,

Johannes

The best and most safe method is to carry out all the processes in aseptic conditions using the solutions and buffers supplemented with antibiotics. I think all the current sterilization methods affect the composition or properties of your hydrogel.

The following paper may be useful:

Article Improved Sterilization of Sensitive Biomaterials with Superc...

Mazaher