Recent developments in affinity-based selection of aptamers for binding disease-related protein targets

The early diagnosis of cancerous or infectious diseases is of interest in medical biology and biochemistry. For such purposes, specific proteins such as cancer biomarkers and viral/bacterial proteins have been molecularly targeted by conventional antibodies for rapid and on-site detection. Recently, DNA aptamers have emerged as superior alternatives to the antibodies based on their high binding affinities and advantages in production. To select aptamer sequences from large DNA libraries, Systematic Evolution of Ligands by EXponential enrichment, or SELEX, has been used for almost 30 years. To date, a number of SELEX techniques have been developed to select specific aptamer sequences against cancer biomarkers or viral/bacterial proteins, resulting in an increasing number of discovery of aptamers exhibiting high binding affinities for the target proteins. In this review, we discuss recent (within 3 years) developments in affinity-based selection of DNA aptamers that are specific to disease-related proteins, such as proteins from tumors and viral/bacterial pathogens. The medical and physiological significance of these proteins motivated researchers to make chemical and physical variations to SELEX, which are introduced and discussed.