Toward Point-Of-Care Diagnostics To Monitor Mmp-9 And Tnf-Alpha Levels In Inflammatory Bowel Disease

We have investigated the association of matrix metallopeptidase 9 (MMP-9) and tumor necrosis factor alpha (TNF-alpha) levels with colitis severity using an established IL10-/- mouse model, which reflects the severity of inflammation in humans with inflammatory bowel disease (IBD). We found that MMP-9 and TNF-alpha correlated with colitis severity. In parallel, we developed assays to detect fecal MMP-9 and serum TNF-alpha using "cap and release" mesoporous silica nanoparticles (MSNs). MMP-9 peptide substrates as "caps" were attached to dye-loaded MSNs. The introduction of MMP-9 resulted in substrate cleavage and subsequent dye release, which was rapidly detected using a fluorometer. For TNF-alpha, an anti-TNF antibody was used as the "cap". The introduction of TNF-alpha antigen leads to the release of the dyes because the antigen binds more strongly to the antibody cap. The MSN-based assays can detect MMP-9 and TNF-alpha effectively, although signal amplification is required to meet clinical sensitivity.