Aptamers, also known as nucleic acid aptamers, are an in vitro screening technique that uses systematic evolution of ligands by exponential enrichment (SELEX) to obtain structured oligonucleotide sequences. The sequences obtained by technical screening can be nucleic acid or deoxynucleic acid. These sequences can recognize them and bind to specific small molecules with strong affinity. Single-stranded oligonucleotides undergo a complex adaptive folding process, forming specific three-dimensional spatial structures using various intermolecular forces such as complementary pairing between nucleotides, hydrogen bond formation, π - π stacking effects, and electrostatic interactions. Next, these three-dimensional structures bind to the target small molecules using intermolecular interaction forces. In recent years, small molecule nucleic aptamer has shown its application potential in the detection of pollutants in the two disciplines of environmental engineering and food science. Small-molecule pollutants are the main detection objects in these two major disciplines. Pollutants include toxins, antibiotics, endocrine disruptors, pesticides, and other substances, which have a great impact on human health and food safety, so how to detect them is now a hot area of research. Due to the importance of contaminants, aptamer screening techniques for small molecule targets have now become a new field for scientists to explore.TEK Biotech can provide customers with small molecule aptamer services, facilitating the establishment of follow-up testing methods and other applications.

As a detection tool in the field of modern scientific research, small molecule nucleic aptamer is considered an alternative product of antibodies and can play its role in the field of detection technology, drug development, and biology. In contrast to the tedious preparation of antibodies, the preparation of aptamer abandoned the reaction and binding in the organism and chose to select the sequence of the oligonucleotide with high affinity capable of binding to the target small molecules in vitro. During the in vitro screening process, the experimenter can adjust various parameters, such as the temperature of incubation, PH, and incubation time, to improve the performance of the best-obtained aptamer. At the same time, after the target sequence is screened and identified, we can use the machine to synthesize the sequence. A high degree of automation in this process can ensure that the differences between the sequences produced in each synthesis are very small. In extreme environments such as high temperature, and strong acid and base environments, the stability of the aptamers is also stronger than the naturally produced antibodies, and they can quickly recover their natural structure, and again bind to the target small molecules. Aptamers are also able to quickly complete labeling, whether fluorescent, nanoparticles, or other functional groups, providing an ideal component choice for biosensor construction.

Currently, the three main screening techniques used by scientists are target fixation-based screening technology, innovative Capture-SELEX (library fixation screening technology), and GO-SELEX (SELEX using graphene oxide). Although the method of target fixation may affect the result due to steric hindrance and other conditions, this method is simple to operate and is deeply loved by people. At the same time, the Capture-SELEX technology, which has been widely used in recent years, also needs our special attention. Given the above three technologies, We selected the key experimental conditions such as library design, positive screen target concentration setting, negative screen target selection, and concentration control, and then found the relationship between the affinity and specificity of the aptamer. By analyzing the screening process and results of more than 30 different target aptamers, some scientists found that the affinity of the aptamer can be improved if the concentration of the positive screening target is lowered, but this step is not necessary in the experimental process. Scientists have also found that the specificity of the aptamers obtained by existing technologies makes it difficult to meet some application criteria. We can adopt a negative screening technology that can help us improve the specificity of the aptamer and optimize our screening process.

During the development of small-molecule aptamers, the researchers have discovered and used different modifying groups, including DNA / RNA bases, sugars, and phosphate components, to modify the aptamers. Notable is that the sugar and phosphate group of aptamer modification, helps aptamer improve the ability of nuclease to its degradation, the group after the modification of aptamer ability, can help small molecule aptamer better should be in drug discovery, the development of biosensor and other fields. In addition, some groups can modify the aptamer, which can help stabilize the three-dimensional spatial conformation of the active aptamer, which in turn promotes tight binding to the target small molecules. In addition, some groups can modify the aptamer, which can help stabilize the three-dimensional spatial conformation of the active aptamer, which in turn promotes tight binding to the target small molecules. In the field of small molecule aptamer recognition, the literature enhancing DNA / RNA aptamer specificity by base modification is now scarce. In published studies, researchers have used thymine to replace conventional uracil and added other modified DNA aptamers to maintain binding activity to ATP, despite a reduced affinity. This study demonstrates that the introduction of external functional groups within a reasonable range can expand the application of aptamers without significantly interfering with the aptamer core function.

Some scholars have proposed and implemented a new strategy, to study and develop high-affinity aptamers that can efficiently bind to small molecules. The core of this strategy is the use of existing DNA aptamers with thermal stability to give them new functions and targets. First, we collected the DNA aptamer library with excellent thermal stability and then predicted these aptamers using biological techniques. Through this prediction process, we could successfully select alternative aptamers with high affinity. To further test the above predictions, we used MST experiments to measure the strength of the aptamers and small molecules when binding, while we also simulated the interaction mechanism between them. The results of the simulations can also help us to determine whether that base pair plays a key role. In addition, the scientists have explored some non-SELEX screening methods, such as non-equilibrium capillary electrophoresis (NECEEM) of equilibrium mixtures, and non-SELEX capillary electrophoresis technology, which can efficiently express and select nucleic acid aptamers without multiple rounds of screening.Pro-SELEX technology, developed by Northwestern University after years of research, can realize the quantitative screening of aptamers with high binding affinity through microfluidic chips. This method can improve the accuracy and success rate of aptamer screening.TEK Biotech is committed to providing customers with a short screening cycle, and high successful efficiency of small molecule nucleic acid aptamer screening technology services, to help each customer's scientific research.