Aptamers are single-strands of DNA or RNA (ssDNA or ssRNA), selected for their ability to bind pre-selected targets with high affinity and specificity. These strands coil and contort into unique tertiary structures; binding molecules through shape — not due to their genetic material.
Aptamers work in a variety of applications and can be successfully used as diagnostics, biosensors, therapeutic and analytical tools, and basic research in place of antibodies. DNA aptamers — also known as oligonucleotides — are increasingly being used in a variety of diverse applications. Aptamers’ small size and diverse structures allow them to bind:
Aptamers are selected from large random libraries through an iterative process known as SELEX — Selective Evolution of Ligands — through Exponential Enrichment. Base Pair Biotechnologies’ natural and modified libraries contain approximately 1,015 unique sequences, each around 32-40 nucleotide bases long. Two constant regions bookmark each aptamer sequence for PCR priming.
In a conventional SELEX workflow, the library is exposed to a single target. Bound aptamers are partitioned and amplified, progressing to the next round. With each cycle the stringency of the binding conditions is increased. Eventually, the aptamers that remain will bind the target with high specificity and affinity. Once multiple rounds of SELEX are completed, conventional cloning and sequencing are used to identify the DNA sequence.
Base Pair’s proprietary selection process follows a similar methodology to SELEX, but hugely increases efficiency for customers by multiplexing up to 30 targets per run.
Switching from antibodies to aptamers is not a major technical leap; their uses overlap in many applications and involve similar validation and workflow steps. Aptamers have proven efficacy in:
Aptamer technology gives you more control over how you do your science. Expanding your range of:
Perhaps most importantly, aptamers are an alternative when the antibodies you’re working with are unreliable, unpredictable and expensive.
Commercial antibodies are far from perfect, but through their long history in the scientific field they remain the status quo. When aptamers and SELEX selection technology were first characterized in 1990, antibodies were widely established in research, clinical and commercial laboratories. Aptamer uptake and advancement has been restricted by patents which are increasingly expiring. Their full potential is now being unleashed. In 2015, aptamer-based technology has advanced and the field is wide open for discovery and licensing of key aptamer sequences.
The key frustrations of antibodies remain, stemming from two key causes: how they are manufactured and how the fundamental molecules behave. Antibodies are proteins, typically manufactured using animal models (in vivo). Aptamers on the other hand, are strands of nucleotide bases, selected and replicated in test tubes (in vitro). What does this mean for reagent performance in your lab?
Discuss switching from antibodies to aptamers by contacting Base Pair now