Optimization Studies On The Manufacturing Process Of Colloidal Gold-based Detection For Ractopamine

Objectives:Improving colloidal gold production process bases on the existing production process of colloidal gold strip of ractopamine,including the preparation of gold solution, gold conjugate preparation, nitrocellulose membrane treatment and shelf life.To achieve the similar quality in multi-batch productions, and then has good shelf life.Methods:To adopt single factor test when preparing colloidal gold solution, change the reaction time and concentration of sodium citrate, and we observe the dispersion and uniformity of gold particles by using visible light spectrophotometer (400～700nm) and scanning electron microscopy. In process of gold nanoparticle combining with RAC antibody, we design five different dilutions and coupling time as conditions.Then choose the best coupling conditions according to experiments above. Nitrocellulose membrane are drying at 37℃and 55℃,then compare the effect of antigen and secondary antibody in five days.Contrasting with 3 groups which storage at room temperature, the aging experiment is chosen at 37℃. Types of processing in 3 groups are untreated, heat treatment, freezing.At last, to repeat experiments 3 times, all conditions are base on best results that improved above.Observe the difference effect of final assembly of test trip.Results:When concentration of sodium citrate is 5% and reaction time is about 20min we can obtain colloidal gold solution with centralized size particle,single and good dispersion.The best conditions for RAC antibody conjugating with gold nanoparticles are that 30 mimutes or more for coupling time and more than 15-fold diluted antibody.Under the temprature of 37℃, it costs 4 to 5 days to reach a steady state on nitrocellulose membrane,but at 55℃it costs 3 days only.The aging experiments show that colloidal gold test trips whether they are treated or not can be stability in 6 months at room temperature.And effection of test trips store at 37℃don't change significantly. But the time extende to 6 months, the quality of the strip has dropped, the sensitivity increased to 10ng/ml. The results show that the different effection between multi-batch test trips still exist, but the difference was not conspicuous, and no effect on sensitivity.Conclusions:This study is to consummate the manufacturing process of colloidal gold test trip of ractopamine, including preparation of gold solution, complex gold-nanoparticles with RAC antibody, NC membrane treatment, and ultimately through the acceleration test we will know how long the test trips can be stored. Between products there is non-significant differences and all products are in good repeatability and stability.