共找到 20 条结果
A series of NaRE(CO3)2 compounds (RE = Ce-Lu, Y, Sc) was synthesized under high-pressure and high-temperature and characterized by single-crystal X-ray diffraction and Raman spectroscopy. Combining these data with previously reported results for NaLa(CO3)2 reveals three distinct structure types dictated by the RE3+ species: an orthorhombic phase (Pmc21) for larger REs (La-Nd), a monoclinic phase (P21/c) for smaller ones (Tb-Lu, Y), and a trigonal dolomite-type (CaMg(CO3)2, R3̅) uniquely for Sc. Intermediate rare earths (Sm-Gd) failed to crystallize into NaRE(CO3)2 under our conditions. Structural evolution arises from lanthanide contraction and the rigidity of CO32- units. As the RE3+ radius decreases, RE-O bonds contract, while C-O bonds remain inflexible, causing incomplete bond adjustment and accumulating strain. This strain elevates lattice energy until a phase transition alleviates it, enabling reduced coordination numbers. In the monoclinic phase, positional disorder of Na+ serves as an additional strain-relief mechanism, accommodating a less symmetric coordination environment. The findings elucidate how lanthanide contraction and carbonate rigidity dictate phase transitions and cation disorder, offering critical insights into coordination flexibility in rare-earth chemistry. Moreover, the dolomite-type NaSc(CO3)2 broadens the structural family of rare-earth carbonates and exemplifies heterovalent substitution (Na+ + Sc3+ for Ca2+ + Mg2+).
Currently, there is no established treatment for post-ischaemic reperfusion-related injury, namely reperfusion injury (RI), which paradoxically exacerbates microvascular and tissue damage in any reperfused ischaemic organ territory. During the ischaemic phase, the autoregulatory apparatus in a subtended organ region temporarily loses its pressure-regulating function because of the combined effects of drastically increased oxygen demand and ischaemic insult. Therefore, it cannot protect the hypoxically injured distal capillary bed from the detrimental effect of the sudden and uncontrolled pressure rise that occurs during the initial phase of reperfusion. This acute capillary barotrauma caused by abruptly initiated reperfusion at systemic pressure can be regarded as an iatrogenic trigger for subsequent damage in the reperfused organ territory. From this haemodynamic perspective, RI can be redefined as a 'capillary hyperpressurization syndrome', dictated by the 'initial reperfusion pressure'. Accordingly, initiating reperfusion gently at lower pressures [pressure-controlled reperfusion (PCR)] and maintaining it at that level until protective autoregulatory myogenic control mechanisms recover may provide substantial benefit in limiting the progressive damage caused by post-ischaemic abrupt and full-pressure reperfusion. In this review, we revisit RI from this haemodynamic perspective and suggest that the same pathomechanism-namely, acute exposure of ischaemically injured microvascular endothelium to an uncontrolled pressure rise during the initial reperfusion phase-predominantly dictates post-reperfusion damage in the heart and in other organ ischaemia-reperfusion settings, where PCR techniques may help limit post-reperfusion damage.
Precisely tailoring the macroscopic morphology of covalent organic frameworks (COFs) fundamentally drives their physicochemical properties. However, the robust and highly directional nature of covalent bonds makes such control at the single-crystal level a formidable challenge. Resolving this bottleneck, we establish a synergistic Brønsted and Lewis dual-acid catalytic strategy to dictate the controlled axial growth and morphological evolution of large (≥50 μm) three-dimensional(3D) COFs single crystals (the XNU-375-X; X = 1-6, a, p, EtOH) featuring a dia topology. Modulating the concentration of dysprosium trifluoromethanesulfonate (Dy(OTf)3), acting as the Lewis acid, drastically suppresses the twinning rate. Consequently, this targeted regulation drives a continuous morphological transition from octahedral to tetragonal bipyramidal geometries. Single-crystal X-ray diffraction (SCXRD) explicitly confirms the microscopic structural consistency throughout this macroscopic evolution. Crucially, during guest solvent removal and exchange, these crystallographic analyses directly capture a rare structural flexibility and dynamic "breathing" effect, evidenced by a massive 46% volume variation. Density functional theory (DFT) calculations elucidate the underlying growth kinetics. Conditional on the specific exposed facets ({100} versus {001}), Dy3+ exhibits differential adsorption behaviors that effectively passivate lateral free amine sites. To the extent that these sites govern horizontal proliferation, this selective binding simultaneously promotes ordered c-axis stacking and intrinsic self-correction. Ultimately, this work bridges the gap in the precision morphological tailoring of 3D COFs single crystals, providing a robust platform for the anisotropic growth and targeted synthesis of complex porous architectures.
Aging is accompanied by a progressive decline in immune function, a process termed immunosenescence, which affects both innate and adaptive immune compartments. Among these, the adaptive immune system-and particularly T cells-undergoes the most profound functional and phenotypic alterations, critically impairing host defense against infections, cancer, and vaccination responses. The age-associated decline of adaptive immunity is shaped by the divergent senescence pathways of CD4+ helper and CD8+ cytotoxic T cells. While both lineages enter a state of cell-cycle arrest, their distinct immunological roles dictate fundamentally different molecular triggers, metabolic adaptations, and functional outcomes. This review synthesizes these subset-specific differences, highlighting how DNA damage-dependent mechanisms and DNA damage-independent processes drive distinct senescence phenotypes. Furthermore, we discuss how these differences contribute to immune system remodeling during aging and explore emerging therapeutic strategies targeting metabolic and signaling pathways to mitigate T cell senescence.
Glycan-lectin interactions at cell surfaces regulate numerous biological processes but remain challenging to characterize at the molecular level. Glycosylation heterogeneity results in lectin-binding targets─from purified glycoproteins to the cell-surface glycocalyx─presenting multiple glycan epitopes simultaneously. Concurrently, distinct lectins often exhibit overlapping glycan binding selectivity, with similar affinities for widely distributed epitopes. Consequently, how lectins compete and achieve selective recognition at glycoprotein and cell-surface levels remains poorly understood. Here, we introduce 19F lectin tagging, as an NMR-based approach to probe these complex glycan-mediated binding processes. Incorporation of 19F probes into lectins yields simple, background-free spectra, enabling binding studies in complex biological environments, including the cell surface. Importantly, this approach also allows the analysis of lectin mixtures with overlapping glycan specificities while individually resolving their binding behavior. We focus on galectins, a family of multifunctional and N-acetyllactosamine (LacNAc)-binding lectins that regulate diverse processes at the cell surface, to dissect their competitive binding behavior across targets of increasing complexity, from small carbohydrates to glycoproteins and the cell-surface glycocalyx. Our results provide insight into the mechanisms underlying the recognition of the immune checkpoint glycoprotein TIM-3 by galectins and reveal competitive binding between some galectin family members at the cell surface. Collectively, these findings reveal that galectin specificity is not dictated solely by LacNAc recognition but instead arises from the molecular context in which glycans are presented, including multivalency and competition for shared glycan ligands. More broadly, they highlight the potential of 19F lectin tagging to investigate binding events in biologically relevant systems.
Neisseria gonorrhoeae pilin antigenic variation (pilin Av) is a complex diversity generation system. Pilin Av depends on a Rec-dependent gene conversion event initiated by an R-loop (gar sRNA) and a resultant G-quadruplex (G4) DNA structure. Mutations of the garP promoter or the G4-forming sequence each prevent pilin Av. We targeted a Type I-C CRISPR interference (CRISPRi) complex to the mutant garP or G4 loci, and CRISPRi targeting to a specific location on the leading strand restored pilin Av. In contrast, targeting the CRISPRi complex to other locations on either the leading or lagging strand was lethal. The CRISPRi restoration of pilin Av depended on the standard recombination factors, confirming the conserved pathway. Inverting the garP-G4 region confirmed that the target strand dictates viability and Av outcome. Together, these results reveal that we can replace the R-loop and resultant G4 structure by specific CRISPRi targeting, providing insights into nucleic acid, secondary structure-dependent genome dynamics.IMPORTANCENeisseria's pilin antigenic variation remains one of the most sophisticated DNA diversification processes in bacteria, yet the trigger that initiates recombination remains unclear. Here, we show that targeting a Type I CRISPR interference complex is sufficient to restore pilin variation in strains unable to form an R-loop or a G-quadruplex structure. Our findings reveal that the position and strand of R-loop formation, rather than its precise sequence context, determine whether cells undergo antigenic variation, remain viable, or die. This establishes a new framework in which localized topological stress, not a particular DNA structure, plays a role in Neisseria gonorrhoeae pilin antigenic variation.
A central challenge faced by the immune system is not simply detecting microbes but determining how to respond to them. In the intestine, where commensals and pathogens coexist, this decision is neither binary nor dictated by a single receptor. Instead, it emerges from the integration of signals across multiple pattern recognition receptors (PRRs), which together encode microbial identity and context. Among these, C-type lectin receptors (CLRs) occupy a unique position. By recognizing diverse ligands present on bacteria, fungi, viruses, and even host derived molecules, CLRs extend microbial sensing beyond pathogen detection to include signals of tissue state and environmental context. In doing so, CLRs function not merely as detectors of specific microbes, but as regulators that calibrate immune responses across the spectrum of tolerance and defense. Many reviews exist that detail how CLRs regulate pathogen defense, so here we will focus on the recent literature that demonstrates how these molecules influence maintenance of homeostasis with our commensal microbiota.
Worldwide, new technologies appeared to be inevitable for human being. Man is the creator of all these technologies but the core question is whether these innovations are dangerous and threatening for creativity, especially in arts. Technology significantly influences art creativity by providing new tools and mediums, such as digital painting and virtual reality, which expand the artistic possibilities. It also enhances the accessibility, allowing artists to reach wider audiences and fostering inclusivity within the art community. This relationship between art and technology isn't new, but the digital revolution has accelerated changes at an unprecedented pace, creating exciting new possibilities while challenging the traditional notions of creativity, ownership, and what we even consider "art" in the first place. While AI can enhance efficiency, it lacks the instinct, emotion, and nuance that human-driven storytelling provides. Emerging technologies such as Artificial Intelligence (AI), Virtual Reality (VR), and blockchain are re-shaping the creative industries by enabling new forms of expression, expanding access to global audiences, and redefining how art is produced, distributed, and experienced. However, if an AI creates a piece, should the credit go to the machine, the programmer, or the artist who directed it? There is a completely understandable and reasonable concern that AI-generated art may lead to homogenization, where artworks start to look similar due to reliance on the same algorithms and datasets. While the nature of the creative process is under debate, many believe that creativity relies on real-time combinations of known neural and cognitive processes. Every original work, whether it is a music or a painting, contains within it that invisible sign of inimitableness, which Benjamin called 'the aura'. A convinced suspicion of the original work, whether it be a music, novel or a painting, saves within itself that invisible sign of irreversibility dictated to the aura.
Blood flow dynamics in microvessels dictate the transport modes of circulating tumor cells (CTCs) and, consequently, influence their metastatic potential. While extensive biochemical and biological studies have advanced our understanding of CTC metastasis, precise experimental measurements and accurate theoretical predictions of its mechanical underpinnings remain limited. To address this gap, this chapter presents numerical modeling of CTC extravasation from the bloodstream, encompassing the critical steps of adhesion and transmigration. The simulations reveal that CTCs preferentially adhere to regions of positive curvature in curved microvessels, a phenomenon attributed to favorable wall shear stress gradients. Subsequent analyses underscore the significant influence of blood's particulate nature on CTC adhesion in these vessels. Moreover, red blood cell (RBC) aggregates enhance CTC adhesion by imparting an additional wall-directed force. Furthermore, modeling a single cell traversing a narrow slit-to mimic transmigration-demonstrates that alterations in cell shape and surface area play a more pivotal role than cell elasticity in enabling passage through such constrictions. Finally, numerical simulations of CTC-RBC separation in microfluidic devices, featuring varied microcolumn geometries and arrangements under diverse flow regimes, were presented to optimize the sorting system's design.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The choice of initial pharmacotherapy-rate control versus rhythm control and which agent-is a critical clinical decision. Beta‑blockers and flecainide are both used first line, but have distinct mechanisms and safety profiles that dictate appropriate patient selection. This state‑of‑the‑art review provides a clinically focused, evidence‑based comparison of beta‑blockers and flecainide for first‑line AF management, emphasizing patient selection and practical decision‑making, synthesizing data from landmark trials (Cardiac Arrhythmia Suppression Trial, Atrial Fibrillation Follow-up Investigation of Rhythm Management, RACE, EAST‑AFNET 4), recent guidelines (American College of Cardiology/American Heart Association/American College of Chest Physicians/Heart Rhythm Society 2023, European Society of Cardiology 2020), and contemporary studies. Beta‑blockers are safe and mortality‑reducing in patients with structural heart disease (coronary artery disease, heart failure with reduced ejection fraction, left ventricular hypertrophy) and are effective for both rate and rhythm control. Flecainide offers superior rhythm control efficacy but is absolutely contraindicated in structural heart disease due to proarrhythmic risk (Cardiac Arrhythmia Suppression Trial). In patients with structurally normal hearts, flecainide is a first‑line rhythm‑control option, including a "pill‑in‑the‑pocket" strategy. No direct head‑to‑head trial compares beta‑blockers versus flecainide as monotherapy. The presence or absence of structural heart disease is the primary determinant of first‑line drug selection. A practical clinical algorithm based on this assessment is provided to guide therapy. Ongoing uncertainties include the role of these agents in the era of early ablation and in heart failure with preserved ejection fraction.
The imbalance of pro-inflammatory and immunosuppressive constituents in the tumor microenvironment (TME) significantly dictates cancer progression, immune invasion, and treatment response. Immunosuppressive regulatory T cells (Tregs) are associated with decreased disease-free survival due to their ability to suppress anti-tumor immunity. Notably, in response to environmental cues, Tregs display functional and phenotypic plasticity with inflammatory helper T cell subsets. Given their predominant role in sustaining immune suppression, it is remarkable that multiple developmental pathways converge to regulate Treg development and function. In this study, we designed, validated, and employed a novel genetically modified mouse model to conditionally ablate the Hedgehog (Hh) gene, Gli2, specifically in Tregs. Ablation of Gli2 activity in Tregs significantly reduced tumor burden, impaired Treg suppressive function, and shifted the transcriptional balance of Foxo3 and Rorγt, transcription factors essential for Tregs and Th17 cells. Spatial mapping highlighted that Gli2 ablation in Tregs enhances the immunogenicity of the tumor and promotes a pro-inflammatory milieu of the TME. This was underscored by a higher tumor immune signature score and enhanced infiltration of cytotoxic CD8+ T cells into the tumor. These findings highlight Hh/Gli2 signaling in Tregs as a mechanistic regulator of immunogenicity in the TME and a potential therapeutic target to prime tumors for enhanced responsiveness for adjuvant treatments.
Programmable photovoltaic functionalities offer a route to integrating energy conversion with information processing. However, existing approaches, relying on either heterostructure design or gate-free architectures based on ferroelectricity and ion migration, suffer from complex device architectures dictated by single-field modulation, where electrical bias simultaneously governs addressing and state switching, imposing an intrinsic constraint on spatial selectivity, architectural simplicity, and operational efficiency. Here, we introduce light as an independent, spatially resolved degree of freedom to decouple addressing from switching, establishing a light-electric dual-field programming paradigm for photovoltaic systems. Using anomalous photovoltaic effects in van der Waals ZnIn2S4 as a model system, we demonstrate nonvolatile, reconfigurable states with retention exceeding 100 days. Spatially localized illumination selects where programming occurs, while a global electric field switches the state, enabling selector-free operation without per-pixel wiring. The programmable response originates from the [ZnS4] tetrahedral distortion and is markedly enhanced by pressure modulation. We demonstrate self-powered visual information processing with 87.9% accuracy in noisy image classification. These findings establish dual-field programming as a powerful strategy to lift the intrinsic constraints of single-field control, leveraging light as an independent control dimension to enable selector-free programmable photovoltaics and advanced optoelectronic architectures.
Electrospun silk fibroin nanofibers (SFNFs) combine exceptional biocompatibility, tunable mechanical properties, and a native extracellular matrix (ECM)-mimetic architecture, making them compelling scaffolds for tissue engineering. Despite rapid progress, current research often pursues isolated material enhancements, lacking a cohesive strategy that aligns scaffold design with the complex biophysical and biochemical microenvironments of targeted tissues. To bridge this gap, this review presents a "design-application coupling" framework that systematically integrates SFNF composition, processing, and surface modifications with tissue-specific regenerative demands. Rather than exhaustively detailing basic manufacturing, we concisely distill advanced electrospinning modalities and targeted functionalization strategies─such as inorganic reinforcement and immunomodulation─that dictate mechanical robustness and bioactivity. Crucially, we map these engineered properties directly to their emerging clinical applications, comprehensively analyzing SFNF performance in the regeneration of bone, skeletal muscle, cardiovascular, neural, and skin tissues. Finally, we discuss critical challenges to clinical translation, including scalability and regulatory standardization, and propose future directions toward smart, bioresponsive materials. This framework provides a systematic pathway from bench-side innovation to bedside application, guiding the next generation of SFNF-based regenerative scaffolds.
Modulating the cation distribution of magnesium spinel ferrites (MgFe2O4) offers a strategic pathway to optimize their functional properties. This study reports the synthesis of novel, mesoporous binary mixed ferrites (Mn0.5Mg0.5Fe2O4 and Cu0.5Mg0.5Fe2O4) via a rapid sol-gel auto-combustion method to achieve selective separation of target metal ions from complex aqueous matrices. Structural and morphological characterizations confirmed the formation of phase-pure, cubic spinel structures (average crystallite sizes of 24-35 nm) featuring interconnected, sponge-like mesoporous architectures. Surface analyses identified abundant oxygen vacancies and hydroxyl groups, which act as critical active sites for inner-sphere metal complexation. Both nano-ferrites exhibited super-paramagnetic behavior; however, the Mn-doped variant demonstrated a higher saturation magnetization (56.33 emu g-1) compared to the Cu-doped ferrite (37.97 emu g-1), enabling highly efficient post-treatment magnetic separation. In competitive multi-metal sorption assays, the transition-metal dopants dictated distinct, pH-dependent selectivity profiles. Mn0.5Mg0.5Fe2O4 exhibited high affinity for Zn2+ separation at pH 6, while Cu0.5Mg0.5Fe2O4 acted as a precision sorbent, achieving exceptional (∼95%) targeted selectivity for Ag+ recovery. These findings demonstrate that targeted metal doping effectively tailors the interfacial chemistry of spinel ferrites, establishing them as robust, magnetically retrievable platforms for both toxic metal remediation and high-value resource recovery.
Phosphorus (P) is a fundamental nutrient governing primary productivity, with its mobility and bioavailability primarily dictated by specific fraction. In floodplain wetlands, P fraction dynamics are critical for regulating nutrient cycling and water quality. This study investigated P fractions and release potential along two representative transects (X and T) in the Poyang Lake wetland. Modified sequential extraction and adsorption isotherms were applied to elucidate environmental drivers and ecological risks. The results indicated that: (ⅰ) concentrations of inorganic phosphorus (IP) and bioavailable phosphorus (BAP) in transect X (IP: 35.52-568.94 mg/kg; BAP: 19.18-298.44 mg/kg) were notably higher than those in transect T (IP: 45.45-435.48 mg/kg; BAP: 14.35-184.55 mg/kg); (ⅱ) the relative abundance of P fractions followed the order of occluded phosphorus (Oc-P) > iron bound phosphorus (Fe-P) > aluminum bound phosphorus (Al-P) > detrital calcium-bound phosphorus (De-P) > authigenic calcium-bound phosphorus (Au-P) > exchangeable phosphorus (Ex-P); (ⅲ) soil P generally showed surface accumulation, but its vertical gradient varied spatially and often deviated from a simple linear decline; (ⅳ) soil properties, including nutrients (TC, TN), chemical state (pH), and texture (sand content), were the dominant environmental drivers; and (ⅴ) interannual P evolution was predominantly driven by the frequency of hydrological fluctuations, where drying and wetting frequency remodels soil substrates to drive divergent active phosphorus responses and determine internal release risks in river connected lakes. These findings elucidate the linkages between P fractions and environmental factors in Poyang Lake, providing a scientific basis for wetland conservation and eutrophication mitigation.
Despite extensive studies on acid resistance in geopolymer mortars and nanosilica modification, degradation mechanisms are still largely inferred from isolated performance indicators such as strength loss or mass change, limiting mechanistic interpretation across different acid chemistries. In this study, a multi-parameter, mechanism-oriented evaluation framework is proposed to distinguish acid-type-dependent degradation regimes in nanosilica-modified metakaolin (MK) and fly ash (FA) geopolymer mortars exposed to hydrochloric (HCl, 4%) and sulfuric (H₂SO₄, 3%) acid environments. Mass change (ΔK), dimensional variation (ΔD), amorphous phase reduction quantified by XRD-based amorphous dome integration (ΔAmorphous), and strength retention (SR) were evaluated concurrently and statistically correlated across four acid-binder systems. The results demonstrate that HCl exposure induces a dissolution-dominated degradation regime, in which strength retention is primarily governed by the stability of the amorphous geopolymer phase, as evidenced by strong negative ΔK-ΔAmorphous correlations (ρ = -0.87 to - 0.90) and positive ΔAmorphous-SR relationships. In contrast, H₂SO₄ exposure leads to a crystallization-dominated regime characterized by sulfate-induced secondary phase formation and crystallization pressure, where strength loss shows a weak dependence on amorphous phase degradation and is instead controlled by internally generated microstructural stresses. Nanosilica exhibits a distinct acid-dependent dual role: low dosages (1-1.5%) enhance gel compactness and restrict ion diffusion, whereas excessive content (2%) accelerates microstructural embrittlement by amplifying crystallization-pressure-driven damage in sulfate environments. Overall, the findings reveal that acid resistance in geopolymer mortars is governed by distinct, quantifiable degradation regimes dictated by acid chemistry. Beyond geopolymer systems, the proposed framework offers a transferable, mechanism-based strategy for interpreting degradation processes in amorphous and nano-modified cementitious materials under aggressive chemical environments.
The gem-difluoroallylated scaffold holds a significant value in medicinal chemistry. However, stereoselective access to its cis-configured motif, thermodynamically disfavored over the trans isomer, remains a long-standing synthetic challenge. Herein, we report a rhodium(III)-catalyzed addition reaction of carboxylic acids to gem-difluoroallylations, which efficiently affords cis-1,1-difluoroallyl esters with high stereospecificity under ambient conditions. Mechanistic studies reveal that the bulky Cp*Rh(III) moiety dictates the stereochemical outcome via steric control during concerted difluoroallene coordination and carboxylate migration, where subsequent metal-centered protonation secures the exclusive cis configuration of the final gem-difluoroallylic products.
Oats (Avena sativa) are a multifunctional cereal in which β-glucan is the primary bioactive component; however, its structural heterogeneity results in functionally non-equivalent fractions. This review demonstrates that β-glucan efficacy follows a continuum governed by weight-average molecular weight (Mw), rather than a binary classification. High-Mw fractions (>1000 kDa) are associated with viscosity-mediated cardiometabolic benefits, whereas low-Mw fractions (<300 kDa) promote fermentation-driven gut and immune responses. Intermediate Mw fractions (300-1000 kDa) provide overlapping functionality, contributing to both metabolic regulation and microbial fermentation. Processing conditions determine these structural transitions. Gentle thermal treatments such as steaming and kilning increase Mw from 1067 to 1713 kDa and from 75 to 1264 kDa, respectively, while enhancing viscosity (115 to 193 cP; 26 to 466.5 cP). Boiling maintains Mw within 1400-1900 kDa and increases extractability from 28% to 37%, while dehulling preserves native Mw. Moderate processing generates intermediate Mw fractions, with cryogenic milling reducing Mw from 2180 to ∼700 kDa and microfluidisation decreasing Mw from 2748 to 350 kDa while increasing solubility by up to 2.7-fold. Pulsed electric fields increase extractability by 94% with minimal Mw reduction (∼371 to ∼339 kDa). In contrast, intensive processing such as extrusion (down to 251 kDa), microwave treatment (1067 to 165 kDa), enzymatic hydrolysis (1000 to 104 kDa), and γ-irradiation (199 to 52 kDa) reduces Mw and viscosity, shifting functionality toward prebiotic and immune effects. Overall, not all β-glucans are equal; processing-induced structural diversity dictates functionality, highlighting the need for targeted Mw design to achieve specific health outcomes.
Mucins are high-molecular-weight glycoproteins essential for the hydration, lubrication, and protective barrier functions of epithelial surfaces. Beyond these physical properties, their dense O-glycan brushes serve as potent multivalent ligands that regulate immune communication through interactions with sialic acid-binding immunoglobulin-like lectins (Siglecs) and other glycan-binding receptors. The translation of native mucins into functional biomaterials is often hindered by the mechanical instability of noncovalent assemblies, and investigations of mucin biology can require well-defined model mucin materials with controlled properties. This chapter presents a detailed protocol for domain-specific covalent crosslinking, a strategy to engineer mucin-based hydrogels with controlled architecture and bioactivity. By selectively targeting either the protein backbone (via carbodiimide/NHS coupling of bioorthogonal handles) or the glycan side chains (via mild periodate oxidation and oxyamine or reductive amination conjugation), the spatial arrangement and mesh architecture of the resulting hydrogel network can be dictated. The two crosslinking approaches yield materials with distinct gelation kinetics, protease susceptibility, pore structure, and immune-modulatory properties, while preserving the bioactive sialic acid residues critical for receptor engagement. The protocol covers the full workflow from mucin dissolution and chemical modification through purification, gelation, and characterization by NMR, HPLC-PAD, and rheometry. By providing a detailed roadmap for manipulating mucin macromolecular architecture, this chapter enables both the design of instructive biomaterials for drug delivery and tissue engineering, and the construction of well-defined model glycoprotein systems for fundamental research on glycan-mediated biology.