ELISA

Based on the core requirements of ELISA experiments, this article will systematically analyze the underlying logic and unique advantages of polystyrene as an ELISA solid-phase carrier from six dimensions: molecular interaction mechanism, optical performance adaptation, chemical stability compatibility, surface modification potential, molding precision advantages, and material comparison analysis, clarifying the core reasons for its irreplaceability.

Serum and Plasma are samples obtained from blood through different processing methods. Due to the influence of the coagulation process, there are certain differences in their components, and these differences are reflected throughout sample preparation and storage. It is important to understand these before sample collection to choose the most appropriate sample preparation strategy.

The core principle of ELISA experiments is the specific binding of antigens and antibodies, while endogenous enzymes in samples can non-specifically catalyze substrate reactions or destroy antigen/antibody structures, leading to abnormal experimental signals and interference. Many customers often encounter issues such as biased test results, false positives or false negatives when conducting ELISA experiments, due to the failure to clarify the sources of various enzymes in the samples and add enzyme inhibitors in a targeted manner. To help customers accurately avoid this experimental pain point and efficiently complete ELISA experiments, EnkiLife has compiled the "Serum and Plasma Enzyme Source Reference Table", while combining core experimental needs to popularize the sources of serum and plasma enzymes and their association with ELISA experimental interference, helping everyone exclude interference and ensure reliable experimental results by clarifying enzyme sources and rationally adding enzyme inhibitors.

The matrix refers to all components in a sample except the target analyte, such as proteins, lipids, salts, pigments, and small-molecule organic substances in the sample matrix. The matrix effect is a phenomenon where these matrix components interact with the target analyte or the analytical system, interfering with the separation, extraction of the target analyte or the detection response, and ultimately causing the analytical results to deviate from the true values. This type of interference is widely present in biological samples such as serum, plasma, cerebrospinal fluid, tissue homogenates, and cell culture media, and is a common cause of poor repeatability and inaccurate quantification in ELISA experiments.

ELISA is one of the fundamental experiments in immunology, and most researchers in the life sciences field are familiar with it. Owing to its characteristics of strong specificity, high sensitivity, and accurate quantitation, ELISA technology is widely applied in both basic scientific research and clinical diagnosis. It is believed that many of our followers who pay attention to us have also performed ELISA experiments. We have compiled a list of common issues that may arise during ELISA experiments for your reference.

The most commonly used solid-phase carrier in ELISA is the microplate made of polystyrene. Its adsorption of proteins forms the basis of the entire detection system, and the core principle behind this lies in the non-covalent interactions between the surface of the solid-phase material and protein molecules.

Coating is the process of immobilizing specific antibodies or antigens on the surface of a solid-phase carrier. Its quality directly affects the sensitivity, specificity, and reproducibility of the experiment. It is equivalent to building an "exclusive reaction platform" for subsequent antigen-antibody reactions.

There are different opinions on the detection and classification of ELISA, and different literatures have different classification opinions in terms of principle or operation. Here we divide ELISA into the following four categories, and then explain each category in detail: (1) direct ELISA; (2) indirect ELISA; (3) Sandwich ELISA; (4) Competition inhibits ELISA. Other ELISA are affiliated with, or derived from, a combination of these four types of ELISA.

Enzyme-labeled antibody technology is a labeling technique that involves covalently conjugating enzyme molecules to specific antibodies. Its core principle is: utilizing the antibody's high specificity for antigen recognition as a "targeting system" to precisely locate the target molecule; then, leveraging the enzyme's highly efficient catalytic "amplification effect" on its substrate to convert an invisible immune reaction into a visible or instrument-detectable signal (such as a color change, luminescence, etc.). This enables the qualitative, locational, or quantitative analysis of the target antigen or antibody.

High background No signal Too much signal - whole plate turned uniformly blue Standard curve achieved but poor discrimination between points Poor duplicates Poor assay to assay reproducibility No signal when a signal is expected, but standard curve looks fine Samples are reading too high, but standard curve looks fine Very Low Readings Across the Plate Green color develops upon addition of stop solution when using streptavidin-HRP Edge Effects