Abstract Poor distribution is often a limiting factor when using affinity targeted treatments. High affinity creates a barrier to transport because proteins cannot diffuse throughout the tissue while bound to the cell surface. Lowering the affinity can help with transport throughout a tumor but can also result in a loss of total delivery and specificity for the target. In this research, we used point mutations to create affibodies with a range of different affinities for epidermal growth factor receptor (EGFR) and measured their penetration through tumor spheroids. Mutants in the range of ∼7–12 nM KD were able to distribute more evenly throughout 3D tumor spheroids without losing total accumulation or receptor specificity. Lower affinity mutants showed both low target specificity and accumulation in 3D tumor spheroids. This work shows the effects of affinity on distribution and how slightly reducing binding affinity can improve transport.
Glaucoma, a leading cause of irreversible blindness, is commonly treated with topical eye drops that reduce intraocular pressure (IOP), but their efficacy is limited by rapid precorneal clearance. To address this, we developed a dynamic hydrogel (CSFP) via Schiff base bonding between carboxymethyl chitosan (CMCS) and 4-formylphenylboronic acid (FPBA) as an advanced delivery vehicle for brimonidine (BRI) and timolol (TIM), two common IOP-lowering agents. The mechanical properties were tunable by adjusting CMCS and FPBA concentrations. The optimized hydrogel exhibited a storage modulus of ∼38.8 Pa (at 1 Hz, 1% strain), excellent self-healing ability, and shear-thinning behavior, facilitating easy administration and resistance to blink-induced clearance. It also achieved near 100% transmittance and a refractive index of 1.339, ensuring optical clarity. Notably, the incorporated phenylboronic acid (PBA) groups enabled selective binding to sialic acid residues on ocular mucins via dynamic phenylboronic ester bonding, prolonging precorneal retention beyond 30 min compared to less than 5 min for the solution control. In a magnetic bead-induced ocular hypertensive rat model, CSFP hydrogel loaded with either BRI or TIM induced greater and long-lasting IOP reduction than the free drug solutions. This work highlights the potential of mucoadhesive dynamic covalent hydrogels for advanced ocular drug delivery.
Dual-antibiotic loaded poly(ethylene glycol) (PEG)-based hydrogels were developed as antimicrobial wound dressings combining covalent and physical antibiotic incorporation. Hydrogels were prepared through amino-yne click conjugation of gentamicin sulfate (Gs) and thiol-yne cross-linking, followed by ciprofloxacin (CPX) loading via swelling-diffusion. The materials exhibited tunable gelation time, swelling capacity, and drug release profiles depending on thiol content. A dual-release mechanism was achieved, consisting of an initial burst release of CPX followed by a sustained, pH-responsive release of conjugated Gs through acid cleavage of β-aminoacrylate linkages. The hydrogels showed effective wide spectrum antibacterial activity against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, while cytotoxicity studies confirmed cytocompatibility at bactericidal concentrations. The results support the potential of these hydrogels as safe and effective dual-antibiotic wound dressings, allowing for the immediate elimination of invading bacteria after wounding (burst release), while maintaining long-term antibiotic release to minimize reinfection risk.
Mechanical loading coupled with moisture sorption causes mechano-sorptive creep in wood, but its molecular origin remains unclear. Here, DMA, in situ tensile FTIR, SAXS/WAXS, and MD/GCMC simulations were combined to examine molecular and nanostructural changes in wood cell walls during sorption under tensile stress. Adsorption under stress produced a higher moisture content than stress-free adsorption, whereas viscoelastic creep at constant relative humidity caused no additional uptake. The enhancement was most evident when the loading was approximately parallel to cellulose microfibrils. FTIR revealed changes in cellulose hydroxyl environments consistent with increased accessibility, while SAXS/WAXS showed enlarged interfibrillar distances with nearly unchanged crystalline lattice spacings. Simulations further indicated reduced polymer–polymer hydrogen bonding, greater solvent-accessible surface area, and pore opening during simultaneous adsorption and loading. Together, these findings link tensile-stress-induced cellulose hydroxyl accessibility to enhanced moisture sorption in the wood cell walls.
This manuscript describes chain-folding-regulated hierarchical self-assembly of an amphiphilic polyurethane (P1), exhibiting superior surface functional group display and biological activity compared to an analogous amphiphilic block copolymer (P3) or a rigid polyurethane (P2) that is deprived of chain folding. In P1, intrachain hydrogen bonding directs the formation of a pleated structure that hierarchically assembles into hollow capsules. A glucose oxidase–peroxidase assay confirmed that this unique assembly of P1 allows displaying ∼50% glucose moieties on the outer surface, which significantly outperforms amphiphilic block copolymers. This renders outstanding multivalent binding with the lectin concanavalin A, as is evident by a very high association constant (∼105 M–1) and spontaneous glycocluster effect. In contrast, P2 or P3 fails to exhibit any notable glycocluster effect under identical conditions. Furthermore, P1, unlike P2 or P3, induced clustering of Staphylococcus aureus by targeting bacterial carbohydrate transporters, deactivated the bacteria, and prevented internalization into mammalian cells.
Silk fibroin (SF) is ideal for aerogel fibers owing to its abundance, biodegradability, biocompatibility, and structural tunability, yet pristine SF aerogel fibers have insufficient performance for practical use. Here, a dual cross-linking strategy combining enzymatic cross-linking and Zn2+ coordination was used, leveraging their noncompetitive inhibition to produce SF aerogel fibers featuring low density, high strength, and outstanding thermal insulation. SF concentration governs the pore architecture formed by enzymatic cross-linking. Zn2+ ions complex with SF molecular chains, creating a more intricate three-dimensional network alongside the covalent bonds from enzymatic cross-linking. At 0.1 M Zn2+, the dual-cross-linked SF aerogel fibers achieve a maximum toughness of ∼0.31 MJ m–3 and optimal thermal insulation with ∼2.9 °C. Woven fabrics outperform commercial nylon, cotton and wool in thermal insulation. Superior performance arises from air-trapping pores suppressing conduction/convection and infrared-reflective pore walls reducing radiative loss. This work provides a guideline for designing biomass aerogel fibers.
Hydrogel dressings have emerged as versatile platforms for wound management. However, effective treatment remains challenging due to complex wound environments involving hemorrhage, bacterial infection, and inflammation. Herei, a multifunctional pH-responsive hydrogel (PCOB 1) was developed via multinetwork cross-linking and freeze-thaw cycles using oxidized pullulan (OP), collagen, poly(vinyl alcohol) (PVA), and borax, and was impregnated with in situ stabilized silver nanoparticles (AgNPs). The incorporation of AgNPs endowed the hydrogel with pH-triggered antibacterial activity, achieving >99% killing of E. coli and S. aureus, efficient biofilm disruption, >90% ROS/RNS scavenging, and catalase-mimetic activity. The hydrogel demonstrated rapid gelation, self-healing, and hemostasis within 33.3 s. The hydrogel promoted macrophage polarization from M1 to M2, enhanced collagen deposition, re-epithelialization, and granulation tissue formation, achieving 98.5 ± 0.6% wound closure by day 14 in vivo. This study presents a multifunctional hydrogel with antibacterial, antioxidant, and anti-inflammatory properties for accelerated wound healing.
Microenvironmental imbalance and bacterial infection are core causes of intractable chronic wounds by hindering nutrient transport and tissue repair. Herein, we innovatively fabricated a hydrophilic antibacterial scaffold based on silk fibroin (SF) and uniformly integrated it into PEGDA microneedle (MN) matrices. The composite MN system can efficiently load hydrophilic model drugs including lidocaine and rhodamine B, achieving uniform drug incorporation and improved drug-loading versatility with controllable, long-term sustained drug release behavior. Biological tests verified that the developed MN possesses excellent broad-spectrum antibacterial capacity against Staphylococcus aureus and Escherichia coli. It also exhibits favorable biocompatibility without obvious cytotoxicity and effectively promotes cell migration. In vivo experiments on full-thickness skin defect models demonstrated that the MN remarkably accelerates wound healing and optimizes healing quality. This work offers an innovative technical strategy for antibacterial drug delivery microneedles, holding great potential for clinical chronic wound treatment.
Conductive hydrogels have risen as a promising material for flexible wearable sensors. However, achieving a hydrogel that simultaneously possesses high mechanical properties, conductivity, self-healing ability, and adhesion remains a challenge. Herein, we developed a dual-network ionic conductive hydrogel (P-P(C-A)-PA) by incorporating poly(vinyl alcohol) and a copolymer of catechol-modified ionic liquid and acrylamide. The optimized hydrogel exhibited outstanding mechanical performance (stress: 883 kPa, strain: 1120%), self-healing efficiency (stress recovery of 58.6% ± 4.6% and toughness recovery of 57.7% ± 5.5%), ionic conductivity (3.91 S/m), and adhesion strength (50 kPa on Ecoflex). The hydrogel-based flexible sensor reliably monitored human motion with rapid and accurate signal response even after self-healing. The hydrogel-based triboelectric nanogenerator showed excellent output performance (180 V, 7.9 μA, and 65 nC), further identifying grasped objects and monitoring finger rehabilitation before and after self-healing. These results highlighted the considerable potential of our hydrogel for applications in advanced electronics.
Collagen, the most abundant protein in mammals, plays a key role in tissue formation and mechanics due to its triple-helix structure. We used atomic force microscopy to study individual type-I and type-III human collagen molecules adsorbed on smooth mica surfaces from low-salt, near-neutral aqueous solutions. Statistical analysis of their two-dimensional contours revealed nonuniform curvature in both collagen types, which persisted after surface drying and molecular dehydration, owing to robust collagen-mica adsorption. In addition, the angle between tangent vectors at the ends of molecular segments followed a non-Gaussian probability distribution, indicative of nonequilibrium quenching of fluctuations upon adsorption to mica. These results suggest that collagen either possesses an intrinsic three-dimensional curvature in solution or acquires a two-dimensional curvature upon adsorption. The first scenario has implications for the self-assembly and elasticity of collagen fibrils, whereas the second has implications in biomaterial design and tissue-engineering strategies.
A Y-shaped fluorinated metallo-zwitterionic monomer NB-Co+-STFSI- with cobaltocenium as the cationic group and sulfonyl(trifluoromethylsulfonyl) imide anion (STFSI, -SO2N(-)SO2CF3) as the anionic group was synthesized via catalyst-free hydroamination and polymerized via ring-opening metathesis polymerization (ROMP) to give the corresponding fluorinated metallo-polyzwitterion, PNB-Co+-STFSI-. In such a zwitterionic system, the introduction of both the hydrophilic cobaltocenium and hydrophobic fluorocarbon unit of STFSI enables the regulation of hydration properties, leading to distinct solution and surface properties that deviate from those of conventional zwitterionic polyelectrolytes. Although the resulting polymer is water-insoluble, the PNB-Co+-STFSI- coating exhibits strong surface hydrophilicity. Using a simple dip-coating process, the PNB-Co+-STFSI- coatings adhere stably to various substrates and demonstrate exceptional antifouling performance, reducing bacterial adhesion by >95% and suppressing protein adsorption to <5% within 8 h; even after 72 h, protein adsorption remains below 15%. This work not only expands the family of zwitterionic polymers but also opens new avenues for the design of advanced antifouling materials.
Zr-based metal–organic frameworks (MOFs) are promising nanomedicine platforms, but their rapid degradation in phosphate-rich biological environments remains a critical barrier to clinical translation. Here, incorporating MnOx into the porphyrinic Zr-MOF PCN-224 modulates the coordination environment of Zr6 clusters, suppressing phosphate-induced linker displacement and extending structural integrity under physiological conditions. The optimized 1:1 MnOx@PCN-224 formulation resists phosphate-triggered disassembly and porphyrin release in phosphate-buffered saline (PBS). MnOx also acts as a catalase mimic, converting endogenous H2O2 into O2 to relieve tumor hypoxia and potentiate sonodynamic therapy (SDT). Under high-intensity focused ultrasound (HIFU) irradiation, stabilized porphyrin linkers generate enhanced 1O2 levels. Functionalization with GST-EGFR as a preadsorbed targeting protein corona enables tumor-specific delivery, and the resulting nanoplatform suppresses tumor growth in a 4T1 breast tumor model. This coordination-driven strategy transforms the inherent lability of Zr-MOFs into a designable parameter for engineering biointerface stability for in vivo therapeutic applications.
Unconventional fluorescent polymers exhibiting multicolor emission have garnered significant interest due to their unique optical properties and broad applications in bioimaging, chemical sensing, and security encryption. In this study, a series of multicolor fluorescent aliphatic hyperbranched polyphosphate esters were synthesized from a natural product. The prepared polymers demonstrated notable red emission, excitation-dependent fluorescence, concentration-enhanced luminescence, and aggregation-induced red-shifted emission. Experimental data combined with theoretical calculations revealed that intermolecular and intramolecular interactions promoted molecular aggregation, thereby enhancing n-π interactions. These strengthened n-π interactions further facilitated spatial electronic communication, leading to prominent multicolor fluorescence. The balance between hydroxyl and triethyl phosphate groups within the polymers promoted aggregation and spatial electronic communication, resulting in longer wavelength emission. Studies showed that the electrostatic potential distribution of the polymers played an important role in regulating their emission properties. Moreover, these polymers were successfully applied in ion sensing and fluorescent hydrogel preparation. This work provides new insights into the emission mechanism of unconventional fluorescent polymers.
New thermoplastic nonisocyanate poly(hydroxyurethanes) (NIPUs) have been designed by polyaddition reactions of carvyl acetate dicarbonate (CADC) with a range of commercial diamines, yielding thermoplastic nonisocyanate poly(hydroxyurethanes) with moderate molecular weights and glass transition temperatures (T g) ranging from −30.5 to 62 °C. Thermal curing of the Jeffamine-derived poly(hydroxyurethane) with the polyacrylate compound LAROMER LR 9000 resulted in the formation of sticky thermoset materials, showing potential for adhesive applications. In addition, curing of bis(glydycyl ether dicarbonate) (BGDC)/CADC blends with polyethylene imine (PEI) enables the formation of tailor-made NIPU thermosets with high stiffness, tensile strength, and low elongation at break.
Peptide self-assembly and liquid–liquid phase separation (LLPS), often mediated by intrinsically disordered regions (IDRs), are natural mechanisms that translate protein molecular features into complex nano- and mesoscale architectures. Although the thermodynamics and kinetics of these processes are well understood, synthetic materials integrating both functionalities remain rare. Inspired by the conserved IDR–assembly domain (AD) architecture of amyloidogenic proteins, we hypothesized that modular recombinant constructs combining LLPS-capable IDRs with β-sheet-forming ADs could generate materials with tunable structural properties. To test this, we engineered a library of elastin-like polypeptides (ELPs) fused to amphiphilic anionic or cationic amyloidogenic peptides, enabling systematic investigation of how sequence parametersincluding ELP length, AD charge, and hydrophilicityand environmental conditions, including temperature, pH, and salt concentration, influence material behavior. Our results reveal links between molecular design and emergent multiscale structures, including micelles and vesicles embedded within coacervates. This work provides a framework for designing hybrid proteins coupling LLPS and self-assembly.
Breast carcinoma is the most commonly diagnosed cancer and a leading cause of cancer-related death among women globally. Conventional treatments are limited by poor targeting, systemic toxicity, and susceptibility to secondary infections, highlighting the need for localized multifunctional therapeutic systems. This study aimed to develop poly(vinyl alcohol)-loaded madecassoside nanofibers (PVA@MAD) as a localized therapeutic platform for breast cancer treatment. Fabricated nanofibers exhibited spider-web-like architecture, swelling behavior, hydrophilicity, degradation, and sustained drug release (∼95% at 72 h under acidic conditions). PVA@MAD showed cytotoxicity against MDA-MB-231 cells, with an IC50 value of 49.31 ± 0.010 μg/mL, inducing ROS-mediated apoptosis and inhibiting cell migration, indicating antimetastatic potential. In addition, the nanofibers showed antibacterial activity against Staphylococcus aureus and Escherichia coli. Hemocompatibility, brine shrimp, acute, and subacute toxicity studies confirmed excellent biocompatibility. Overall, PVA@MAD nanofibers offer a promising localized therapeutic approach combining anticancer and antibacterial activities for improved breast cancer management.
Current vaccine formulations heavily rely on cold chains to avoid degradation during transportation and storage. Vaccines typically degrade when exposed to temperatures outside the 2–8 °C range, leading to waste and logistical challenges, particularly in rural areas. This study investigates the ability of poly(lysine)- and poly(glutamate)-based peptide coacervates to improve the thermal stability of porcine parvovirus (PPV), a model nonenveloped viral vaccine. We hypothesized that both the length and specific amino acid sequence of the peptides forming the coacervates would influence the stability of PPV. Long polypeptides (400–800 mers) provided significant protection, slowing PPV inactivation at 60 °C for up to 7 days by as much as 4 logs (10,000-fold), whereas shorter 48-mer homopolypeptides offered limited stability. Modifying peptide sequences revealed that glutamate-glycine block copolypeptides at larger block sizes improved thermostability, while incorporating alanine residues into lysine block copolypeptides improved stabilization beyond that achieved with long homopolypeptides. The addition of sucrose in the formulations further improved thermostability, while trehalose showed minimal benefit. Although coacervation did not have a significant impact on viral infectivity, in vivo studies leveraging an alum adjuvant demonstrated that PPV released from a coacervate yielded lower antibody responses compared to native virus, indicating the presence of complicating interactions that potentially masked the immunogenic epitopes on the capsid surface or decreased the effectiveness of the adjuvant. Overall, this study showed that coacervate formulations can be adjusted to enhance virus thermal stability; however, further work is necessary to understand how such formulations can provide thermostability without altering the immune response necessary for a successful vaccine. Such design principles would enable the development of formulations that could decrease the vaccine cold-chain dependence and improve vaccine accessibility.
Lignins are heterogeneous aromatic biopolymers whose structural complexity depends strongly on botanical origin and isolation process. Comprehensive characterization therefore typically relies on multiple complementary techniques, including gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and nuclear magnetic resonance (NMR) spectroscopy, resulting in labor-intensive workflows and complex data integration. Here, ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is systematically benchmarked against these established methods using solvent-fractionated spruce kraft lignin as a model system. Complementary electrospray ionization (ESI) and graphite-assisted laser desorption/ionization (GALDI), combined with tandem mass spectrometry (MS/MS) and heterospectroscopic correlation analysis, reproduce fraction-dependent trends in oxygenation, aromatic condensation, and functional group distribution consistent with FT-IR, Py-GC/MS, and quantitative NMR data. While limitations remain for molar mass distributions and linkage quantification, FT-ICR-MS can serve as an advanced, high-throughput complementary screening platform that enables streamlined, comparative molecular-level lignin profiling with reduced analytical complexity.
In this work, a multicomponent boric acid cross-linking strategy was developed to prepare cellulose-based RTP materials, using sodium carboxymethyl cellulose as the rigid matrix, poly(vinyl alcohol) (PVA) as the auxiliary network regulator, boric acid as the dynamic covalent cross-linker, and 9-phenanthreneboronic acid (PA) as the phosphorescent guest. Boric acid forms a dynamic covalent cross-linked network with hydroxyl groups of CMC and PVA, while PA is tightly immobilized in the matrix through hydrogen bonding and boron-associated coordination interactions, constructing a dense and rigid confined microenvironment. The cellulose-based film exhibits excellent RTP performance, with a phosphorescence lifetime of 2.61 s, an absolute quantum yield of 13.85%, and a visually distinguishable afterglow lasting up to 20 s. Meanwhile, the cross-linked structure endows the material with outstanding mechanical properties (tensile strength of 140 MPa). Additionally, the material displays multiple functional characteristics, including time-resolved information encryption, water-rewritable capability, and reversible responsiveness to humidity and pH.
Elastin-like polypeptides (ELPs) are versatile biopolymers for constructing synthetic cell membranes. Applications in biosynthesis, molecular secretion, and payload delivery require an understanding of the solute transport across ELP membranes. In this work, we integrate coarse-grained molecular dynamics simulations with the inhomogeneous solubility-diffusion (ISD) model to investigate the passive permeation of small solutes across ELP membranes of varying sequence composition and stability. We observe that mechanically robust ELP bilayers remain highly permeable to small solutes but exhibit an unexpected nonmonotonic dependence on solute hydrophobicity. By backmapping the coarse-grained bead solutes to all-atom resolution, we identify specific molecular motifs that may promote or suppress solute transport through the ELP membrane. Across different ELP systems, we find that water permeability is only weakly dependent upon membrane stability but strongly dependent upon the ELP hydrophilic guest residues. Compositional analyses suggest that the side-chain flexibility and hydrophilicity of the guest residues in the hydrophilic block modulate interfacial solvation and regulate water permeation. Our results provide a broad computational characterization of ELP membrane permeability and present a predictive tool to tune the sequence of ELP-based vesicles for the engineered passive transport of molecular cargoes.
