Sialic Acids: Structural Diversity, Biological Roles, and Advances in Analytical Techniques

Sialic acids are a family of acidic monosaccharides predominantly found on the terminal positions of glycoproteins and glycolipids, where they play vital roles in cellular interactions, immune responses, and disease pathogenesis. Their structural diversity, including variations in core structures and linkages, contributes to their functional versatility in biological systems. In addition to mediating host-pathogen interactions, sialic acids influence key processes such as neural development, cancer progression, and immune evasion. The advent of advanced analytical techniques, such as high-performance liquid chromatography (HPLC), mass spectrometry (MS), and biosensor-based methods, has revolutionized the detection and characterization of sialic acids, providing enhanced sensitivity, specificity, and structural insights. Despite these advancements, challenges remain, including high costs, technical complexity, and the need for specialized expertise. This review explores the structural diversity and biological significance of sialic acids, emphasizing their role in health and disease. It also provides a comprehensive overview of current analytical approaches, highlighting their strengths and limitations. By addressing existing challenges and identifying future research opportunities, this review aims to underscore the importance of sialic acids in both basic and applied sciences, paving the way for novel diagnostic and therapeutic applications.