Views: 0 Author: Site Editor Publish Time: 2025-06-30 Origin: Site
In cell culture, ELISA analysis, high-throughput screening and other experiments, microplates (especially 96-well plates) are one of the most commonly used consumables. Although they are widely used, there is also an interference factor that is often overlooked - edge effect. If such deviations are not handled properly, they will directly affect the accuracy and repeatability of the experiment.
part 1
The concept and causes of edge effect
The edge effect refers to the deviation of the experimental results due to environmental differences between the outer holes of the microplate (such as the 36 peripheral holes of a 96-well plate) and the center hole. The edge effect mainly occurs in the holes on the periphery of the well plate. Common causes include:
1 uneven temperature
The edge wells heat more slowly than the center wells, possibly causing abnormal cell distribution.
2 evaporation difference
The liquid in the edge holes is more volatile than in the middle holes, and the medium concentration and osmotic pressure will change, thus affecting the cell state.
3 optical interference
When detecting with a microplate reader, the optical path length of the edge hole is different from that of the middle hole, resulting in large errors due to signal interference.
part 2
Experimental design optimization reduces errors from the source
In order to effectively deal with the edge effect, you can start from the aspects of experimental plan, temperature control and consumable selection:
1 Experimental plan optimization
Filling method: fill the edge holes with PBS or culture medium to construct an 'evaporation buffer zone';
Partition control: Each group of samples is distributed in the center and edge holes, and the data is averaged to offset the deviation.
2 Temperature control improvements
Synchronous preheating: Synchronously preheat the well plate and solution to the culture temperature to reduce the thermal gradient;
Pre-incubation strategy: After loading the sample, place it at room temperature for 1-2 hours. After the cells adhere, transfer to a 37°C incubator (suitable for CHO and other cells).
3 Reasonable selection of microplates
Structural design: Grooved orifice plate (after the edge groove is filled with liquid) can significantly reduce the impact of evaporation;
Accessory upgrade: With the condensation ring cover, it helps reduce evaporation and condensation reflux in the edge holes.
part 3
Applicability of plates of different specifications
When the sample volume is large, multiple 96-well plates can be used to run in batches, or 384 or 1536-well plates can be used to increase throughput. However, it should be noted that the greater the number of holes, the smaller the unit hole volume, the more sensitive the edge effect, and the higher the requirements for the consistency and manufacturing process of the orifice plate. In this regard, Aijin Biotechnology can provide professional support:
1 Provides multiple specifications of 96/384/1536-well plate coverage, flexibly adapting to various experimental scales.
2 The panels are made of imported medical-grade polystyrene (PS) material and are produced cleanly in a 100,000-level dust-free workshop with small batch differences.
3 Aijin can realize batch domestic production of 384 and 1536-well plates, providing stable support for high-throughput experiments.
4 The plate types cover transparent, white, black and other types, and are suitable for various detection platforms such as colorimetry, luminescence and fluorescence.
5 The size complies with SBS standards and is suitable for automated instruments.
part 4
Data analysis corrects edge bias
Edge effects are not only a matter of operations and consumables, but may also involve data processing methods:
1 Dual wavelength detection (ELISA, etc.)
Use a sensitive wavelength (such as 450nm) to measure the signal + background, and a non-sensitive wavelength (such as 630nm) to measure the background. The two subtract to eliminate interference, and the CV value can be reduced by 30-50%.
2 dynamic blank control
There are 3 blank holes on each edge and center to calculate the background difference respectively and subtract interference by partition, reducing the inter-plate error by more than 20%.
3 Statistical model correction
Spatial trend analysis: use interpolation method to deduct edge effect trends.
Mixed effects model: Incorporate hole position (row/column) into statistics as a variable to correct for positional effects.
part 5
Special scene solutions
1 Long-term culture (e.g. more than 72 hours)
Place moist gauze (humidity ≥95%) around a high-humidity incubator or well plate;
Add 1-2% PEG 4000 to the culture medium (to reduce evaporation), or use HEPES buffer to stabilize the pH.
2 low cost alternative
Aluminum plate uniform heating: use pre-warmed aluminum plate to accelerate the temperature equalization of the orifice plate;
Cover with plastic wrap: reduce evaporation by 40% (leaving holes for ventilation);
Pre-hydrate the edge wells: fill them with PBS 2 hours before the experiment to reduce subsequent evaporation.
The influence of edge effects may run through the entire experiment. Only by starting from the source and comprehensively optimizing the design and execution can the data be stable and reliable. Aijin Biotechnology provides multiple specifications of well plates such as 96, 384, and 1536 wells, covering different throughputs and detection needs. The products have good consistency and strong adaptability, and can provide stable support for various scientific research experiments.
