Specific Binding Agents for the Molecular Recognition of Biotoxins: Recent Advances and Applications in Forensic Toxicology

The precise detection and profiling of biotoxins are of paramount importance in analytical and forensic toxicology. Investigating these toxicants within highly chaotic background matrices—ranging from postmortem biological fluids to suspected poisoning vehicles such as complex dietary and environmental samples—requires robust recognition molecules capable of overcoming severe interference. This comprehensive review summarizes recent analytical developments in biotoxin detection, categorizing molecular recognition platforms into three primary types: immunological recognition (antibodies and recombinant derivatives), aptamer-based recognition, and entirely synthetic recognition (molecularly imprinted polymer, MIP). To meet the rigorous ultra-trace demands of medicolegal analysis, we further discuss the strategic integration of these recognition elements with powerful catalytic amplification cascades, highlighting the transition from natural biological enzymes to highly durable nanozymes and DNAzymes. By detailing recent structural optimizations and preparation strategies, this review critically evaluates the respective advantages, matrix tolerances, and limitations of each recognition mode when applied to diverse and challenging analytical samples. Finally, we provide a forward-looking perspective on the translational potential of these specific binding agents, emphasizing how computational rational design and portable integration will overcome practical bottlenecks in modern toxicological investigations.