There are, at this point, many in vivo reagents with varying effectiveness based on the target tissue for silencing. Nanoparticle approaches seem to have the highest efficiency (see an example here: https://altogen.com/product/nanoparticle-in-vivo-transfection-reagent/) but even then delivery to organs like the brain is far less efficient than say the kidney. Regardless, in vivo gene silencing is an established procedure, and the FDA recently approved the first therapy based on RNAi, so it's gaining prominence in the field.

hello,  I have used this product in the past and have it published.  We used Mirus TransIT In Vivo Gene Delivery System.  We infused the siRNA with this delivery system directly into the renal capsule to knock down cav1 expression in rats.  We were able to reduce cav1 protein expression by 75%.  Where and what protein are you looking to knock down with the siRNA? Are you infusing the siRNA in rats, mice?  Below I have listed the publication in which we used this product

Am J Physiol Renal Physiol. 2011 Apr;300(4):F914-20. doi: 10.1152/ ajprenal. 00380. 2010. Epub 2011 Feb 2.

Inhibition of renal caveolin-1 reduces natriuresis and produces hypertension in sodium-loaded rats.

Gildea JJ1, Kemp BA, Howell NL, Van Sciver RE, Carey RM, Felder RA.

To what model would you like to deliver the siRNA - mice? chicken? zebrafish? xenopus? c. elegans? bacteria?

Is the developmental stage important? Do you want a systemic delivery? Organ specific? Cell specific?

More info is required. 

Dear Lahoucine,

There is a very recent reagent dedicated to targeted delivery of siRNA: in vivo SilenceMag.

It uses the Magnetofection technology to both target and enhance delivery: it combines magnetic nanoparticles and small RNA that will be retained after injection at the magnetically targeted site.

In attached files you can find results with in vivo Magnetofection; some of them are related to in vivo SilenceMag.

you can contact me directly at: [email protected] for more information or if you would like to try this reagent.

good luck with your experiment,

best regards,

Cedric

the rodent i am planing to use is golden hamster. these animals have catheter that implanted in the heart and i am going to use that to inject the siRNA. The gene i want to knock down is expressed mainly in the liver.

that can be difficult because the siRNA has a tendency to start acting as soon as it hits tissue.  I am not sure that there will be siRNA remaining in the circulation to affect the liver if you infuse it through the heart catheter.  Have you thought of making a midline incision and exposing the liver to infuse the siRNA directly?  It would only require a small incision into the liver which could be covered in vetbond tissue adhesive to create a healing scab.  We do this all of the time in our lab when we are infusing siRNA directly into the renal cortex of rats.  Also, maybe you could infuse the siRNA into the hepatic duct following a midline incision.  

Bonjour Lahoucine

Nous on utilise :

Lipofectamine RNAiMAX transfection Reagent (Life Technologies) according to the manufacturer’ instructions.

Invivofectamine 3.0 is great, and its pretty much the only option on the market- as in vivo delivery is still a huge challenge. We developed Invivofectamine 2.0 earlier, and this is next gen reagent "one step up"