The Critical Role of Glycans in Biological Systems
Glycans, also known as polysaccharides or complex carbohydrates, are intricate sugar molecules attached to proteins, lipids, or other glycans, forming glycoproteins, glycolipids, and proteoglycans. These structures play pivotal roles in cellular recognition, signaling, immune responses, and pathogen interactions. In humans, N-linked glycans—attached to asparagine residues on proteins—are particularly vital, influencing everything from protein folding to disease progression. Aberrant glycosylation patterns are hallmarks of cancer, autoimmune disorders, and infectious diseases, making precise glycan analysis essential for biomarker discovery and therapeutic development.
China's research institutions, including those under the Chinese Academy of Sciences (CAS), have long prioritized glycomics as part of national biotech initiatives. The Shanghai Institute of Materia Medica (SIMM), a CAS affiliate, exemplifies this focus through its State Key Laboratory of Drug Research, where interdisciplinary teams bridge chemistry, biology, and nanotechnology.
Long-Standing Challenges in Glycan Sequencing
Unlike linear nucleic acids or proteins, glycans exhibit extensive branching, isomeric diversity, and non-templated biosynthesis, rendering traditional sequencing arduous. Mass spectrometry (MS), the gold standard, often yields ambiguous fragment ions due to labile glycosidic bonds, requiring extensive derivatization and databases for interpretation. Nuclear magnetic resonance (NMR) offers structural detail but demands milligram quantities, impractical for biological samples. Enzymatic sequencing via exoglycosidases is sequential and time-intensive, limited to linear chains.
These hurdles impede glycomics progress, particularly for branched N-glycans prevalent in therapeutic glycoproteins like monoclonal antibodies. Global efforts, including from the US National Glycomics Consortium and Europe's GlycoUniverse, underscore the need for scalable, single-molecule methods.
CAS Researchers' Breakthrough: Fragmentation-Reassembly via Nanopore Technology
On March 10, 2026, researchers from SIMM-CAS, led by Zhaobing Gao and Bingqing Xia, published a landmark study in the Journal of the American Chemical Society detailing a nanopore-based glycan sequencing method using a fragmentation-reassembly strategy. This innovation addresses branched glycan complexity by breaking them into analyzable fragments, reading them individually, and computationally reconstructing the full structure.
Affiliated with the University of Chinese Academy of Sciences (UCAS), many authors hold dual roles, highlighting CAS's integration of graduate education and cutting-edge research. The work builds on prior nanopore DNA/RNA sequencing successes, adapting Oxford Nanopore Technologies' principles to glycans.
Step-by-Step Breakdown of the Fragment Reassembly Strategy
The method unfolds in four integrated phases:
- Enzymatic Fragmentation: Intact glycans undergo mild hydrolysis with endoglycosidases (e.g., Endo H for N-glycans), yielding structurally defined oligosaccharide fragments while preserving branch information.
- Nanopore Detection: An engineered α-hemolysin (α-HL) nanopore mutant enhances glycan capture and translocation, generating unique electrical current blockades—'fingerprints'—for each fragment based on size, charge, and topology.
- Reference Library Construction: A multidimensional dataset of ~1,000 glycan fragments is built via machine learning classifiers, achieving high specificity even for isomers.
- Sequence Reconstruction: Fragment signals from unknowns match library entries probabilistically. Full topology emerges via set-theoretic logic: intersections identify core motifs, unions accommodate branches, and differences resolve ambiguities.
Tested on biantennary N-glycans, the pipeline delivered 93.71% fidelity, robust against noise, isomers, and mixtures. For details, see the JACS publication and bioRxiv preprint.
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Experimental Validation and Performance Metrics
In proof-of-concept experiments, the team hydrolyzed model biantennary complex-type N-glycans into 5-10 fragments, achieving >95% fragment-level accuracy. Reconstruction succeeded for 20+ glycoforms, including those with bisecting GlcNAc and core fucosylation—common in therapeutics. The system tolerated 10% biological background (e.g., serum glycans) and scaled to mixtures of 50 fragments.
Compared to MS, it requires femtograms of sample, operates label-free, and provides single-molecule resolution. Complementary work from Nanjing University's Shuo Huang group in Science Advances (Jan 2026) validated similar assembly for linear oligosaccharides, reporting 94.1% event classification via MspA nanopores—synergizing CAS efforts.
Implications for Drug Discovery and Personalized Medicine
Glycosylation dictates ~50% of therapeutic protein efficacy; inconsistencies cause immunogenicity in biologics like erythropoietin. This strategy enables real-time quality control in manufacturing and patient-specific glycan profiling for cancer diagnostics—where tumor glycans serve as biomarkers.
In China, where biopharma R&D investment hit RMB 500 billion in 2025, CAS's advance accelerates 'Made in China 2025' goals. SIMM's focus on glycosylation inhibitors for inflammation aligns perfectly, potentially slashing development timelines by 30%.
China's Rising Dominance in Glycomics and Nanopore Innovation
CAS institutes like SIMM and UCAS train 10,000+ PhD students annually, fueling biotech talent. National programs, including the 14th Five-Year Plan, allocate ¥100 billion to synthetic biology, positioning China as nanopore leader—evidenced by patents surpassing the US in 2025.
Collaborations with Oxford Nanopore expand access; UCAS campuses host training, democratizing tech for regional universities like ShanghaiTech.
Stakeholder Perspectives: From Academics to Industry
CAS Director Zhaobing Gao emphasized modularity: 'This completes our nanopore glycan toolkit, from hydrolysis to assembly.' Industry partners, including WuXi Biologics, hail cost reductions (10x vs. MS). Global experts, per Nature Glycoscience, predict commercialization by 2028.
Challenges remain: database expansion for O-glycans, clinical validation. Yet, pilot studies at Peking Union Medical College show promise for IgG glycan biomarkers in rheumatoid arthritis.
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Broader Impacts on Chinese Higher Education and Research Ecosystem
SIMM-UCAS exemplifies 'double first-class' university reforms, blending elite training with innovation. Over 200 glycomics theses since 2020 underscore momentum. International exchanges, like with GlycoNet Canada, enhance multi-perspective views.
This positions China amid US-EU competition, fostering jobs in Shanghai's Zhangjiang Hi-Tech Park—home to 500+ biopharma firms.
Future Outlook: Scaling to Clinical and Industrial Applications
Next steps include AI-optimized classifiers for 100k+ glycoforms and portable devices for bedside analysis. Projections: 20% glycomics market growth to $2B by 2030, China capturing 30% share. Actionable insights for researchers: integrate with GlycoDraw for fragment prediction; industries, adopt for biosimilar QC.
CAS's strategy heralds a glycomics era, empowering China's higher education to lead global biomedicine.