Novel Strategies and Tools for Enhanced Sensitivity in Routine Biomolecule Analytics

The combination of flexible and robust immunoassay technology with the sensitivity of DNA as a signal amplification template is realized in Immuno-PCR (“IPCR”). Classical ELISA is converted to IPCR by exchange of antibodyenzyme detection conjugates with antibody-DNA conjugates. The value of ultra-sensitive analytics deriving from this for pharmaceutical R&D is threefold: (I) Deeper understanding of biomolecular interactions for the development of new compounds. (II) Monitoring of compounds at very low concentrations in toxicokinetic and pharmacokinetic clinical studies. (III.) Control of compound functionality and therapeutic effects by surveillance of characteristic biomarkers and/or immunogenicity reactions. This review summarizes background information about general selection of IPCR targets, actual standard assay procedures and work with biological matrices. Quantitative real-time detection as well as optimized reagents and protocols revealed a typically 100-10,000-fold increase in sensitivity and a broad dynamic range compared to ELISA. Case studies are discussed for (I) the analysis of biomolecular interaction with proximity ligation technologies and IPCR, (II) pharmacokinetic studies of novel drugs with validation data for assay precision and recovery and (III) biomarker profiling, including cytokine multiplex assays and polyplex trace analysis in extremely small sample volumes. In a survey of results from recent innovations, the potential of this emerging field of applications is evaluated for novel pathways in study design and analytics.