Application of the magnetizable cellulose particle in development of CRP radioimmunoassay

Solid phase-based radioimmunoassay (RIA) procedure for quantification of C-reactive protein (CRP) is an important tool for the clinical analysis. CRP, an inflammatory protein belongs to pentameric protein family was described by Tillet and Francis in 1930 while working with Streptococcus pneumoniae. Quantification of the CRP by a sensitive immunoassay is the need, and to fulfill this we have developed a rapid and user-friendly RIA by employing separation system based on antibody coupled with magnetizable cellulose nanoparticle. In the present study development of separation system is achieved by coupling of anti-CRP antibody with magnetizable particle coated with cellulose residues. The coupling reaction was carried out by 1, 1' carbonyl-di-imidazole (CDI) activation method. The magnetizable nanoparticle-based separation system was found responsive, it had better S/N ratio which reduces non-specific binding (NSB) and results in increased assay sensitivity. These magnetizable cellulose particles were prepared by wet grinding method, where a mixture of iron oxide containing manganese ferrite core and cellulose are stirred in a ball mill. Size of prepared particles was below 3.11 μm. The wet grinding process is established inhouse (Indian patent no.193445) by BRIT, Mumbai. The developed assay has the added advantage of flexibility in using solid-phase magnetizable immunosorbent as per the specific requirement of any assay or research