The improvement of sensitivity of competitive ELISA kits requires multiple aspects such as experimental design, reagent optimization, and operational procedures. Here are some key strategies:

1. Antibody optimization

‌High affinity antibody: Select primary or secondary antibodies with stronger binding ability to the target antigen to enhance the specific signal.

‌Antibody concentration adjustment: Determine the optimal antibody concentration through pre experiments to avoid excessive background or insufficient background, which can lead to weak signals.

2. Sample processing

‌Concentrated samples: Concentrate low concentration samples (such as ultrafiltration, freeze-drying), but avoid excessive concentration to introduce interfering substances.

‌Reduce matrix effects: Dilute the sample or use matrix matched standards to reduce the interference of impurities in the sample.

3. Enzyme labeling system enhancement

‌Highly active enzymes: Use enzymes with higher catalytic efficiency, such as HRP or ALP, to label secondary antibodies or antigens.

‌Signal amplification technology: Introducing the biotin streptavidin system (such as ABC method) to further amplify the signal.

4. Sealing and washing

Sealing agent selection: Optimize the sealing agent (such as BSA, skim milk powder, or specialized sealing solution) to reduce non-specific binding.

‌Strict washing: Increase washing frequency or optimize washing buffer (such as adding Tween-20) to reduce background noise.

5. Substrate and color development

‌High sensitivity substrates: Use luminescent substrates (such as ECL) or fluorescent substrates instead of traditional chromogenic substrates (such as TMB) to improve the detection limit.

Extend color development time: Appropriately extend the color development reaction time (linear range needs to be controlled).

6. Optimization of standard curve

Increase standard point density: Increase the gradient of standard samples in the low concentration range to improve quantitative accuracy.

‌Fitting algorithm: Choose a more suitable curve fitting method (such as four parameter logistic regression).

7. Equipment calibration

Calibration of ELISA reader: Ensure accurate calibration of instrument wavelength and optical path to avoid reading errors.

Notes:

Balanced competition ratio: In competitive ELISA, the competition ratio between free antigen and labeled antigen needs to be optimized through pre experiments to avoid excessive competition leading to signal suppression.

‌Avoid excessive modification: When labeling antigens, their immunogenicity should be preserved, as excessive modification may affect competitive efficiency.

If specific reagents or protocol suggestions are needed, further explanation of application scenarios (such as detecting small molecules, hormones, etc.) can be provided

The above is the knowledge about correctly storing unused ELISA kits that the editor has introduced to you. Wuhan Genomics is a professional manufacturer of ELISA kits and antibodies, specializing in ELISA kits for humans, rats, mice, pigs, cows, sheep, plants, etc. Monoclonal antibodies, polyclonal antibodies, and labeled antibodies are complete, highly sensitive, and specific, supporting customization and free testing. The product quality is first-class, and we welcome everyone to consult.