Improving reagent performance in immunoassays both to enhance assay sensitivity and to minimize interference are ongoing challenges in clinicalÂ diagnostics. We describe herein the syntheses of a new class of hydrophilic reagents containingÂ sulfobetainesÂ zwitterions and their applications. Sulfobetaine biological detergents, such asÂ SB-08,Â SB-10,SB-12,Â SB-14,Â SB-16.
SB-14 a sulfobetaine surfactant for protein solubilization in medical, biological and diagnostic applications.
TheseÂ zwitterionicÂ biological detergentsÂ are potentially useful for improving the properties of immunoassay reagents. We demonstrate for the first time that zwitterion labeling is a general and viable strategy for reducing the non-specific binding of proteins to microparticles and, to improve the aqueous solubility of hydrophobic peptides. We also describe the synthesis of zwitterionic cross-linking reagents and demonstrate their utility for peptide conjugation.
In automated, chemiluminescent immunoassays, improved assay performance was observed for a hydrophobic, small analyte (theophylline) using an acridinium ester conjugate with aÂ zwitterionicÂ sulfobetaineÂ linker compared to a hexa(ethylene)glycol linker. Sandwich assay performance for a large analyte (thyroid stimulating hormone) was similar for the two acridinium ester labels. These results indicate that zwitterions are complementary to poly(ethylene)glycol in improving the aqueous solubility and reducing the non-specific binding of chemiluminescent acridinium ester conjugates.
Biological detergentsÂ are used to purify, isolate or solubilize membrane proteins while preserving the proteinâ€™s biological activity; they are also used to selectively prepare culture media by inhibiting certain bacteria growth, and to isolate, purify, crystallize or renature proteins. AG Scientific is known for carrying the highest quality zwitterionic CHAPS and MOPS buffers, this has allowed us to achieve a leadership position as a preferred supplier for University researchers & Biotech manufacturers worldwide.
Source:Â ZwitterionicÂ reagents for labeling, cross-linking and improving the performance of chemiluminescent immunoassays.Â A Natrajan, D Sharpe, and D Wen,Â Org Biomol Chem, March 7, 2012; 10(9): 1883-95.