Dear Roslinda,

I read that in Poland (http://ichf.edu.pl/home_en.html) they used gold nanoparticles within hydrogel structure to maintain antibacterial effect and do not harm human cells. But, still I have found explanations of the product in Polish (http://ichf.edu.pl/press/2015/02/IChF150219a_PL.pdf). Maybe you will find some additional informations elswhere (like patents or papers).

Good luck.

Best regards,

Michał W.

There's hardly any bacteria that will survive a shot of bactericidal emergency antibiotics like vancomycin + cefotaxime.  It's the fungi you'll need to worry about. 

Roslinda,

If you start your hydrogel preparation with a non sterile biomaterial there is no effective way of eliminating bacteria especially for hydrogels. You can always try adding antibiotics/antimyctotics in your culture media and increasing the frequency of media change to restrict the bacterial/fungal growth but you cannot eliminate it 100%. If you are following John's suggestion, make sure that you eliminated all that excess loads of antibiotics before seeding your cells.

So I would  suggest you to start  with a sterile material and do all your hydrogel preparation under aseptic conditions .

Always use the recommended concentrations of antibiotics/antimycotics in your culture media and increase the frequency of your media change.

All the best !!

Binulal

As Prabhu and Binulal have suggested, UV and sterile filtering might be the best thing to try in terms of effort for efficacy. A lot depends on the concentrations of ingredients and the steps you use to make your hydrogel. You could try UV treating the powder prior to formulating your gel, but there is some guess work involved in doing that. My advice would be to avoid filtering a solution for sterility then lyophilizing back to a powder (more complicated than it sounds, and a lot of bad things can happen to your chitosan if your lyo cycle isn't optimized). If you can, start by ordering a cell culture grade stock of chitosan and use aseptic/sterile technique from that point forward.

Good luck!

I agree with most of the answers above. once you have made your stock solution of chitosan, you can filter it through a 0.22 micron filter. Once you have synthesized the hydrogels you can give it a gradient treatment starting with 20% ethanol all the way to 100% for 10 min each ( you may even leave the hydrogels in 70% alcohol overnight). Then expose the scaffolds to UV treatment for around half an hour after which you can wash your gels with PBS supplemented with 1% antibiotic/antimycotic solution. This should help prevent any form of contamination in your cell culture work with the hydrogels.

If your hydrogel is a film you could use UV radiation to sterilize it. But if it is a suspension you can filter ir (depending on the concentration).