Solution to the accumulation of microspheres on the membrane during chromatography
Blocking the ball:
It is generally defined as the phenomenon of aggregation of label conjugates between the binding pad and the bottom of the NC membrane;
Bonding Pad Release:
The process of whether the sprayed and dried marker can be eluted by the sample solution and chromatographed on the NC membrane within the interpretation time;
Spray ball (gold) method:
Spray the marker evenly onto the bonding pad through a scriber or soak it;
Lyophilized ball (gold) method:
Dispense markers into wells of enzyme plates or other containers for vacuum drying and solidification;
According to the fixation method of markers, POCT lateral chromatography products can be divided into: spray ball (gold) method and freeze-dried ball (gold) method.
At present, more people tend to use the spray ball (gold) method. The advantages are that it can save preparation cycles, reduce packaging steps and reduce normal costs, etc.; the usage amount of markers can be relatively controllable; the client operation only requires one step, and the operation fault tolerance rate is further reduced. ; The disadvantage is that the dried marker is not easy to elute, and the uniformity of the spraying process amplifies the CV value of the product, requiring pretreatment of the bonding pad.
In the freeze-dried sphere (gold) method, the sample is first mixed during the test process, or it can be incubated after mixing before proceeding to the next sample loading process. Usually, the product sensitivity and CV of this method are better than those of the spray ball (gold) method. The disadvantage is that this method will have excess markers. During the interpretation time, the color development gradually increases. After the interpretation time, the T-line color development remains. The changes are relatively obvious; if quantitative product development is carried out, the interpretation time is more stringent, and the amount of sample loaded will also affect the interpretation results.
Ball blocking solutions for spray ball (gold) products:
Ensure the dispersion of the marker, and try to ensure that there is no precipitation in each dissolution step during the labeling process. If there is any, it is best to let it stand to remove the precipitate before use;
Ensure that the marker can be stored for a week in a liquid state at 2-8 degrees; mainly examine the stability of the marker and whether the corresponding solution matches the corresponding marker;
There are sample diluent products available through
(1) First, under the premise of the same pH value, replace different pH buffer pairs and add 0.5% T20. Under the premise of ensuring normal chromatography, check whether the ball blocking situation has improved;
(2) Under the premise of determining the pH buffer pair, determine whether different pH values have an impact on ball blocking;
(3) Under normal circumstances, this two-step debugging can solve the problem of ball blocking, but it will sacrifice certain product performance, such as color intensity, etc.;
(4) If operations (1) and (2) cannot solve the problem, you can test the difference between different surfactants accordingly;
(5) If there is a significant decrease in color development, adjust it by adding macromolecular polymer;
If the product does not have sample diluent, the corresponding process will be adjusted in the binding pad or sample pad;
Release solution for bonded pads:
Most existing projects use fiberglass 8964, which generally requires pretreatment. It is not recommended to add a large amount of protein, especially casein, when processing the conjugation pad; it is also not recommended to add high molecular polymers to improve color development to the conjugation pad.
The spraying amount should be as low as possible. Some projects may have poor color development, and the spraying amount needs to be increased to improve the color development;
T20 can be appropriately added to the binding pad, but it needs to be done according to the characteristics of the marker. Some projects may have an aging process and a decrease in color development.
The bonding pad can be made by adding small molecular alcohols or polysaccharides. Generally ok.
Replace fiberglass
