Hi! Elisa,  

As your previous method, you did not use crosslinker for chitosan hydrogel. To make chitosan hydrogel, you can use crosslinker such as glutaraldehyde, genipin, diisocyanate, and tripolyphosphate. If you want to make hydrogel without chemical crosslinker, you can make physical crosslinker by using freeze/thaw method. 

For example, In your condition, just add 10% (this is so high conc.) of glutaraldehyde instead of lactic acid. You can obtain chitosan hydrogel.

Thanks. 

Hi, thank you for your answer. I was wondering the same but I asked to the authors of the paper and they replied giving me the same protocol just mentioning LA and chitosan so I was thinking that I was doing something wrong.

The hydrogel should have an in vivo application so I am not so confident in using glutaraldehyde. Do you think that I can follow this protocol for the physical thawing ?

"freezing at −20 °C for 18 h and thawing for 6 h at 25 °C for three continuous cycles, to provide mechanically acceptable hydrogel properties for further experiments."

Thank you for your help,

Elisa

Hi!

If you want to apply in-vivo test such as non-toxic condition, you can use a genipin instead of GA. Also, 1wt% GA solution can be make chitosan hydrogel. It depends on the just total molar ratio. I had been use 1% chitosan solution with 1% GA solution to prepare hydrogel. 

The resultants of freeze thaw method are very different. It is very hard and time cosuming fabrication. Also, physical crosslinking  without additional treatment is not stable in water. 

I recommend to use a genipin. There are a lot of biomedical application.

Thank you for your help. 

BW, 

Elisa

You have to functionalized the chitosan for the better hydrogel other wise you get physical hydrogel 

We modify chitosan with addition of methacrylic anhydride to form methacrylamide chitosan with double bond that facilitates photo-crosslinking.

hi, i prepared chitosan gell by dissolving 0.5g in 50 ml of 1% acetic acid solution. i got viscous gell

Hi, you did not mention the viscosity of Chitosan because the gelling of chitosan depend on viscosity of chitosan e.g. There is chitosan low viscosity , chitosan medium and high viscosity .

Effectivement, il faut dissoudre le chitosane dans une solution d’acide faible, comme l’acide acétique ou bien l’acide lactique.

Une fois dissoutes, les molécules de chitosane portent une charge positive.

Pour obtenir un hydrogel rigide, il faut faire réagir ces molécules chargées positivement avec une solution d'un polymère chargé négativement, comme l'alginate ou le polyphosphate.

Je vous suggère de lire l'article suivant:

Examen microscopique des billes de chitosane-polyphosphate avec des spores piégées de l'agent de lutte biologique, Streptomyces melanosporofaciens EF-76

Jobin, Guy ; Grondin, Gilles ; Couture, Geneviève ; Beaulieu, Carole .

Microscopie et microanalyse ; Cambridge  Vol. 11, N ° 2,  (avril 2005): 154-65.

Pour toute autre information, communiquez avec moi à l'adresse suivante:

[email protected] .

Espérant le tout à votre satisfaction,

Guy Jobin, Ph. D. (Biologie)

I have the same problem , i read Many paper they just make the chitosan in Law concentration solution of acitic acide , in m'y case i have i do the same steps ,i dont get an hydrogel chitosan ,i got a gel of chitosan whith hight viscosite.

Can I make the hydrogel solution without adding any tentionative?.

Makhlouf Mohammed Rabeh did you solve your problem?

Barkın Aydın yes, i do did you need any help?

Makhlouf Mohammed Rabeh

Yes I am trying to do a chitosan hydrogel.

I use 1gr chitosan to %1 acedic acid solution (100ml).

For crosslinking I used %1 glutaraldehyde.

What concentration rate of glutaraldehyde should I add to chitosan solution.

And I do not have freeze dryer. Do you have any recommendation for drying process?

Thanks in advance

Barkın Aydın It is recommended to utilize a 5% concentration of GA. With regards to the drying method, air drying or oven drying may be employed. However, oven drying is not advised unless no other options are available.

Makhlouf Mohammed Rabeh monster even on researchgate, good and helpful answer

Oussama Baaloudj you are the greatest researcher my friend we inspired from you