Xiaowu (Shirley) Tang

We report a conductive semi-interpenetrating polymer network (semi-IPN) hydrogel reinforced with fluorescent carbon quantum dots (CDs) hydrothermally synthesized from branched polyethyleneimine and sodium alginate, together with oxidized carbon nanotubes (ox-CNTs), engineered for sequential dual-cargo delivery with pH-responsive release behavior. The hybrid matrix integrates PEDOT:PSS with a poly(acrylamide-co-2-aminoethylmethacrylate hydrochloride) network to form a robust soft material capable of sequentially releasing a neurotrophic protein and a small-molecule therapeutic. UV–visible deconvolution analysis suggested an apparent delayed release profile for glial cell line-derived neurotrophic factor (GDNF) compared with vitamin B12, which may be associated with matrix-cargo interactions within the hydrogel network. The hydrogel exhibits stable swelling behavior, mechanical integrity under physiological conditions, and tunable electrical percolation as a function of ox-CNT loading. Nanofiller incorporation through CDs enhances interfacial interactions, while ox-CNTs establish conductive pathways within the polymer network, enabling control over drug-matrix interactions and release kinetics. In vitro evaluation using MTT assays, DCFH-DA intracellular reactive oxygen species (ROS) analysis, and immunostaining of the neuronal-associated markers βIII-tubulin and MAP2 demonstrated compatibility with HT22 cells, maintenance of neuronal-associated marker expression, and reduced intracellular ROS levels under oxidative-stress conditions. Complementary molecular dynamics simulations provide qualitative molecular-level insight into the intermolecular interactions and conformational changes contributing to hybrid network stabilization. These findings demonstrate the multifunctional performance of the conductive hydrogel and support its further evaluation in advanced neuronal and in vivo models for potential applications in neural tissue engineering, soft bioelectronics, and controlled therapeutic delivery.

Designing recyclable, polymer-free hot-beverage containers is essential for addressing the end-of-life challenges associated with polyethylene-lined paper cups and reducing reliance on fossil-derived barrier materials. In this work, we have developed a fully cellulosic barrier coating by reinforcing cellulose acetate (CA) with cellulose nanocrystals (CNCs) and applying the formulation onto porous paper substrates using a sealed, shear-free dispersion and blade-coating process. The resulting coatings form continuous, defect-suppressing surface layers that bridge macropores and partially integrate with the upper fiber network. Spectroscopic analysis confirms physical blending accompanied by hydrogen-bonding-mediated interfacial interactions between CA, CNCs, and the paper matrix, while Raman spectroscopy further reveals characteristic shifts consistent with enhanced bonding and chemical compatibility at the coating–substrate interface. Thermogravimetric measurements show delayed main-chain degradation and increased char yields with CNC incorporation, whereas electron microscopy reveals progressive surface densification and fiber-matrix interlocking. These structural improvements translate into monotonic gains in tensile strength and modulus, peaking at 5 wt % CNC, with enhanced toughness up to 3 wt % CNC. The coatings maintain integrity during a five-day immersion in protic/aprotic and acidic/basic media, exhibiting no film lift-off or channel formation. Oxygen transmission decreases by more than an order of magnitude relative to uncoated paper with CA alone and reaches low-permeability regimes when reinforced with CNCs. Under extended abrasion testing, commercial polyethylene-lined cups display progressive pitting, boundary opening, and flake-like surface degradation, whereas the CNC-CA surface remains cohesive, adherent, and low-defect, indicating superior resistance to abrasion-induced damage. These findings demonstrate a viable, high-performance fully cellulosic barrier coating that enables recyclable, polymer-liner-free hot-beverage packaging while providing strong mechanical, thermal, solvent-resistance, and gas-barrier performance compatible with a circular materials economy.

Carbon nanotube (CNT)-based ionic nanochannels offer a powerful platform for controlling ion transport at the nanoscale, enabling highly sensitive biosensing modalities based on molecularly gated ion transport. In this work, we design, fabricate, simulate, and experimentally characterize a multi-walled carbon nanotube (MWCNT)-based ionic nanochannel functionalized with single-stranded DNA for label-free detection of complementary nucleic acids. Devices fabricated via CVD growth, mechanical transfer, and microfabrication of integrated reservoirs and electrodes exhibit stable and reproducible ionic transport in KCl electrolytes. Conductance strongly depends on electric double-layer structure and ion-surface interactions, as shown by systematic variation of electrolyte concentration. Covalent attachment of 15A capture strands to CNT termini reduces channel resistance, whereas hybridization with complementary 30T targets results in reproducible, concentration-dependent resistance increases. The sensor exhibits a linear detection regime from 2 to 20 µM with a sensitivity of 1.86 MΩ µM⁻¹ (R² ≈ 0.99). These results demonstrate a deterministic, tunable MWCNT ionic nanochannel platform for quantitative, label-free nucleic acid detection, providing a scalable foundation for next-generation nanofluidic biosensors and molecular diagnostics.

Polymer-based encapsulation systems that enable stimuli-responsive and controlled release are essential for next-generation drug delivery systems. In this work, liquid-liquid encapsulation is used to fabricate pH-responsive polymer capsules containing hydrogel carriers loaded with caffeine and riboflavin. Laser-oil droplets laden with fluorescent particles are first employed as a model system, in which dissolution of the Eudragit L100 shell under alkaline conditions results in rapid, complete release of the encapsulated laser oil-fluorescent particle suspension, thereby providing direct visualization of shell rupture and release dynamics. The approach is then extended to caffeine- and riboflavin-loaded hydrogels encapsulated within Eudragit L100 shells. The resulting capsules remain stable under acidic conditions. However, at near-neutral or basic pH, dissolution of the Eudragit L100 shell results in the release of the drug-loaded hydrogel carriers. The release of caffeine and riboflavin proceeds via a two-step mechanism involving Eudragit L100 shell dissolution followed by diffusion-controlled transport of caffeine and riboflavin from the alginate matrix. Quantitative analysis reveals that the presence of the Eudragit L100 shell introduces a distinct delay in the onset of release and shifts the equilibrium release time, both of which decrease systematically with increasing pH. This system exhibits pH-responsive behaviour, in which the Eudragit L100 shell governs the onset of release, while the hydrogel core regulates the subsequent diffusion kinetics. Notably, compared to the complete release observed in liquid-core systems, hydrogel-based capsules exhibit reduced and sustained release due to the additional diffusion resistance of the alginate matrix. These findings establish a strategy for decoupling release onset from the subsequent diffusion-controlled release within a single platform, providing a scalable route toward controlled, pH-responsive drug delivery.

Respiratory protective textiles increasingly require multifunctional surface treatments that enhance durability and provide active antiviral performance without compromising filtration. In this context, this study develops graphene nanoplatelet–silver nanoparticle (GNP–Ag) and super activated carbon–silver nanoparticle (SAC–Ag) composite coatings for PPE-grade nonwoven fabrics using a room-temperature ultrasonic atomization process. The coatings enhanced mechanical integrity while maintaining baseline filtration efficiency. GNP–Ag increased spunbond grab strength by 54% and, when combined with polyurethane and UV cross-linking, improved meltblown strength by 47%. Surface wettability shifted from hydrophilic to hydrophobic, with meltblown contact angle increasing from 88° to 121°, and wash fastness improved following heat and UV curing. Cytotoxicity assays showed a dose-dependent response, with GNP–Ag exhibiting lower cytotoxicity compared with SAC–Ag. Antiviral testing against human coronavirus OC43 demonstrated a 1.93-log reduction (98.8%) after 10 min for unwashed GNP–Ag fabrics and a 1.43-log reduction (96.3%) after washing. Filtration performance remained unchanged for GNP–Ag and slightly increased for SAC–Ag. These results demonstrate a stable, mechanically reinforcing, and antiviral coating that enhances the protective function of PPE-grade nonwoven fabrics.

This study presents an approach to the synthesis of nanocomposite magnetic hydrogel microbeads using a microfluidic-assisted droplet method followed by in situ gelation in a heated oil column. The beads were fabricated from a semi-interpenetrating polymer network (semi-IPN) comprising gelatin, and vinylic monomers, with incorporation of iron oxide nanoparticles (Fe₃O₄) synthesized via coprecipitation. The unique combination of pressure-mediated bead formation and controlled gelation kinetics enabled tunable porosity, as validated through SEM and pore size distribution analysis, where increased oil column height yielded narrower pore distributions due to enhanced gelation. Magnetic characterization confirmed strong superparamagnetic behavior, while FTIR and XRD analyses verified successful chemical integration of the polymeric and nanoparticle components. Rheological studies revealed enhanced elasticity and network strength in nanoparticle-loaded hydrogels, and swelling/deswelling tests, fitted with first-order and exponential decay models, demonstrated reversible, magnetically tunable water uptake. Furthermore, in vitro cell culture studies showed excellent cell attachment and proliferation on the bead surface, facilitated by the porous, wrinkled morphology. Collectively, these multifunctional beads exhibit significant promise for applications in cell delivery, magnetically guided therapies, and responsive tissue engineering platforms.

Stimuli-responsive biomaterials capable of controlled, on-demand release are vital for next-generation therapeutic delivery. We present a dual-responsive hydrogel platform for the controlled release of dyes from hydrogel cargoes, regulated by both pH and magnetic stimuli. By integrating magneto-responsive sodium alginate hydrogels with ferrofluid, we engineer smart hydrogel cargoes capable of responding to physiological cues as well as to on-demand external triggers. In this work, we utilize the liquid-liquid encapsulation method to generate Rhodamine B dye-loaded hydrogel-based cargoes. Our system enables not only passive, pH-driven diffusion but also active, magnetically enhanced release, demonstrating for the first time dual-mode modulation of release profiles from encapsulated hydrogels within protective oil-based droplets. Upon external magnetic activation, hydrogel cargoes are extracted from their encapsulation and immersed in various aqueous environments, where their release kinetics are finely tuned by both pH-dependent swelling/shrinking and magnetic field-induced structural changes. We found that the incorporation of magnetic actuation significantly increases the effective diffusion coefficient (∼ 10^-9 m²/s) as compared to that for the pH-assisted release (∼10^-10 m²/s) of Rhodamine B from the hydrogel. This approach provides spatiotemporal control over release behavior, paving the way for advanced, remotely controllable strategies in targeted drug delivery, minimally invasive therapeutics, and adaptive biomaterials. Our findings highlight the transformative potential of multistimuli-responsive hydrogels as a versatile platform for next-generation biomedical applications.