One issue that has delayed the revolution is the difficulty associated with the identification of aptamers that bind to a target analyte. For antibodies, the identification process has been well developed and is relatively routine. For aptamers, the reliance on polymerase chain reaction (PCR) based amplifica- tion of very small concentrations of short target DNA molecules can easily lead to artifacts. In addition, without effective counter measures, the immobilization of the analyte onto resin for selection purposes can easily lead to the identification of aptamers for components of the resin, rather than the ana- lyte. It’s been my experience that many published aptamers exhibit significant binding to various resins, and very little to the analyte of interest.

Aptamers have many appealing qualities, including the ability to refold into an active conformation and synthesis with cheap methods in comparison to antibodies (nucleic acids are cheaper and easier to make than proteins). However, a major drawback of aptamers is their low affinity. You've probably noticed that publications involving biosensor development using aptamers focus on just a few targets (e.g., thrombin). These are the few aptamers that have a sufficient binding affinity to be analytically useful. Until someone improves aptamer design methods comparable to produce aptamers with affinities on the order of antibodies (sub-micromolar K_D values), antibodies with be the preferred capture molecule of choice.

I would like to continue on James Wade's answer.

That is true that some targets proved to be difficult for selection of aptamers with high affinity. I am not sure that "design methods" [as I understand this term] is the real problem. Based on some recent results, "chemistry" may be a limitation when DNA or RNA aptamers are selected. Several groups have addressed this issue and developed new chemistries for that purpose.

I would cite in no specific order:

Sullenger's group at DUKE, using 2'-F, 2'-OMe and 2'-OH nucleosides

AM Biotech and Gorenstein's at UT Houston, using X-aptamer platform and dithioates

Somalogics - Larry Gold's company - using Somamers [modified nucleosides as well]

TagCyx - Ichiro Hirao's group at Riken, Yokohama - using non-natural bases

Those groups developed aptamers with affinity in the nM or even pM against 100's or even 1000's of targets alltogether.

Here are a few references:

Xianbin Yang et al., 2011, Expert Opin. Drug Discov., 6(1) 75-87

Gold et al., 2012, Cold Spring Harb. Perspect Biol, 4:a003582

Gold L, et al. (2010) PLoS ONE 5(12): e15004. doi:10.1371/journal.pone.0015004

Kimoto, et al. (2013) Nature Biotechnology, online publication 7 April 2013, doi:10.1038/nbt.2556

Tan et al. (2013), dx.doi.org/10.1021/cr300468w | Chem. Rev. 2013, 113, 2842−2862

Ray et al. (2013), Nucl Acid Therapeutics, online publication DOI: 10.1089/nat.2013.0439

Here is another paper describing more aptamer selection successes and addressing the "support/resin" non-specific binding that is a real concern that has to be addressed when selection experiments/strategy are designed.

Aptamers were first described in 1990, but monoclonal antibodies have been used in clinical situations approximately in 1980 . therefore we can not compare them in this regard.

Thank you

what are you see use and progress of aptamer ?

What I can say quickly is that there has been a scientific meeting organized in Italy in October 2013 [2 months ago]. 177 scientists attended the meeting. That indicates a very strong interest.

The program can be found at: http://www.aptamernaples2013.it/home.asp?pgn=9

That will give you a pretty good idea about the field.

Aptamers are used and/or developed in the following areas:

THERAPEUTICS/DRUGS - for instance REGADO - phase III or NOXXON - phase I and II

DIAGNOSTICS - main reference: SOMALOGICS

BIOSENSORS - many papers, too long for this post... google "aptamer + biosensor"

RESEARCH - see in the aptamer naples 2013 program for many exemple

FOOD SAFETY - see paper from NeoVentures above [Penner 2012].

Some people predict a market for aptamers at 2 billion dollars by 2018. I see that as quite optimistic though. However, the business is growing.

Best regards

Thank you very much mr.lemaitre

But is it mean aptamers will substitute monoclonal ab in further,in diagnosis technics?!

This is the 1 million dollar question indeed.

Personally, being an oligo chemist, I wish and hope that aptamers will progressively displace monoclonal antibodies but I think it will be a long way.

The success of the SOMALOGICS platform is already claiming some success and this is an excellent point - see http://www.somalogic.com/Technology.aspx

A company like Neoventures could also make a step into Food safety analysis with their product - see http://neoventures.ca/products/mycotoxin-testing/

After that, time will tell us how long it will take.

In my opinion, key to success of aptamer is the ability to deliver on the promise that "Good Aptamer lead can be delivered within 3-6 weeks and optimized aptamer can be obtained after an additional 6 weeks". If THAT can become true, aptamer technology will have a serious advantage. And critical to that is for selection companies to have EXCELLENT LIBRARIES to start selection with.

That is how I see the situation.

Thank you very much

i want to begin work in aptamer technics

so i need you and other friends to help me in this topic in further

Don't forget the 1st symposium devoted entirely to aptamers : Aptamers 2014, 24-25 March, in Oxford

http://libpubmedia.co.uk/aptamers-2014/

What is advantage or disadvantage for using anti aptamer antibody or the reverse in molecular detection?

Dear

pls. find the attached file may it help.

Best regards

Houda 

Unfortunately, there are only a few high-affinity aptamers characterized properly and published. If you ask for examples, you nearly always end up with a thrombin aptamer as shown in the presentation attached above.