Kinbio - Analysis of common problems in the development of colloidal gold test strip

3.

Test strip structure
Working principle of test strip
Test strip testing method
NC membrane coating
Colloidal gold marking

The principle is not clear. There are two main hypotheses:
1. Firstly, they are combined by electrostatic force, and then maintained for a long time by
H bond and hydrophobic effect
2. Firstly, the two are combined by hydrophobic action, and then maintained for a
long time by electrostatic action. Depending on practical experience, any factor that can
affect hydrophobic interaction, H bond and electrostatic interaction will affect the binding
of protein to membrane.

17.

18.

19.

20.

☞

21.

22.

The size of colloidal gold particles is mostly 1 ~ 150nm. Small gold particles
are stably, evenly and in a single dispersed state suspended in the liquid to
become colloidal gold solution.
Colloidal gold thus has a variety of colloidal properties, especially its
sensitivity to electrolytes. Electrolyte can destroy the negative repulsion force
of the outer layer of colloidal gold particles, so as to break the stable state of
colloid, make the dispersed single gold particles agglomerate into large
particles and precipitate from the liquid.
Some proteins (BSA, PEG20000) and other macromolecules can protect
colloidal gold and enhance its stability.

23.

24.

25.

26.

27.

28.

=
0.5

29.

30.

31.

1、Sealing principle
A.Fill the blank position of gold particles surface
B.Provide a stable microenvironment for gold markers and resist centrifugal damage
2、Sealing substances: BSA, casein, PEG, PVP, etc.
3、BSA The effect of blocking the blank position on the surface of colloidal
gold is similar to that of marker protein, with three forces; It is relatively mild
and has a wide range of applications, which can reflect the real performance
of labeled proteins.

32.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

1.Main causes: antigen antibody
Antigen antibody supplier
Monoclonal / polyclonal
antibody
2.NC membrane
Manufacturer's process
Dispensing scratch
Speed of flow
Gold water separation / slow
release of gold pad
Coating concentration
Interpretation time / reflow

52.

3.Gold pad
4. Sample pad:
Bare gold
Chemical
Gold particle
reagents
aggregation
Preservative
Antibody
Anticoagulant
labeling
Surface active
amount
Gold solution
dosage / reflux
agent
5.Samples:
Bacteria and cell debris:
hydrophobic
Acid sample
Positively charged
protein
RF
Heterophilic
antibody HAMA
Cross reactive
substance
HOOK