Key Takeaways & Executive Findings
- •• • Schottky Ag0-Ag2S heterojunction on NaYF4:Yb,Tm enables Type I PDT with oxygen-independent hydroxyl radical generation, overcoming hypoxia limitations in uterine tissue; this shifts the therapeutic mechanism from oxygen-dependent Type II to robust Type I, ensuring bactericidal efficacy even in low-oxygen environments. • • Upconversion core allows NIR (near-infrared) activation, achieving deep tissue penetration beyond the ~1 mm limit of visible light, enabling non-invasive treatment of deep endometrial injuries; this addresses a critical bottleneck in clinical PDT. • • Dynamic release of Ag+ ions from the heterojunction provides synergistic bactericidal activity, complementing ROS action and disrupting biofilms; this dual-action approach reduces the risk of antibiotic resistance and enhances long-term antibacterial efficacy. • • PLLA scaffolds fabricated by selective laser sintering (SLS) are biodegradable and patient-customizable, eliminating the need for secondary removal surgery and promoting endometrial regeneration; this integrates structural support with therapeutic function, reducing patient trauma and infection risk.
Abstract
Bacterial infection following endometrial injury delays tissue regeneration and may progress to endometritis and other reproductive disorders. Photodynamic therapy (PDT) offers a promising antibacterial strategy in the post-antibiotic era, yet its efficacy is often limited by rapid recombination of photogenerated charge carriers and poor penetration of visible excitation light. Here, we report a previously unexplored upconversion-mediated, Type I dominant photodynamic antibacterial uterine scaffold specifically designed for infection-associated endometrial injury. The core innovation is the construction of a Schottky Ag0-Ag2S heterojunction on NaYF4:Yb,Tm nanoparticles using ZIF-8 as a sacrificial precursor, enabling efficient charge separation and oxygen-independent hydroxyl radical generation, overcoming the oxygen dependence of conventional Type II PDT under hypoxic uterine conditions. The upconversion core permits deep-tissue-penetrable near-infrared (NIR) activation. Beyond instantaneous PDT, dynamic release of Ag+ ions provides synergistic bactericidal activity, enabling spatiotemporally coordinated biofilm disruption. These nanostructures were incorporated into patient-customizable, biodegradable poly(L-lactic acid) (PLLA) scaffolds fabricated by selective laser sintering, achieving simultaneous antibacterial therapy and endometrial regeneration in a single platform. This integration of an oxygen-independent PDT mechanism, MOF-templated heterojunction engineering, and 3D printed personalized uterine implants constitutes a comprehensive therapeutic strategy not previously reported for treating infection and endometrial injury.
1. Introduction
Infectious endometrial injury remains a major clinical challenge, with approximately 73% of endometritis cases linked to intrauterine infection and bacterial colonization detected in nearly 64% of endometriosis patients. Current management relies on intrauterine scaffolds combined with antibiotic therapy, but frequent antibiotic use leads to microbial dysbiosis and drug resistance, while commercial non-degradable scaffolds require secondary surgical removal, increasing infection risk and patient discomfort. These limitations underscore the urgent need for biodegradable scaffolds with intrinsic antibacterial properties that can simultaneously control infection and promote tissue regeneration.
Photodynamic therapy (PDT) offers a non-antibiotic alternative with high spatiotemporal selectivity, yet conventional Type II PDT is oxygen-dependent and suffers from rapid charge recombination and poor penetration of visible light, rendering it ineffective in hypoxic uterine environments. This study addresses these bottlenecks by engineering a Schottky Ag0-Ag2S heterojunction on upconversion nanoparticles, enabling Type I dominant ROS generation that is oxygen-independent and activated by deep-penetrating NIR light. Furthermore, incorporating these nanostructures into 3D-printed biodegradable PLLA scaffolds provides a unified platform for antibacterial therapy and endometrial repair, potentially eliminating the need for secondary surgeries and reducing antibiotic reliance.
Loading authentic research manuscript (Pages 1–5)...
ZENG Jie, XIONG Feilong, ZAN Jun, WANG Dongan, PENG Shuping, YANG Hejin, SHUAI Cijun (2026). Heterojunction-Enhanced Photodynamic Uterine Scaffold Mediated by Upconversion for Treating Infectious Injuries. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-025-4058-4
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the mechanism of oxygen-independent ROS generation in this scaffold, and how does it overcome hypoxia in uterine tissue?
The scaffold employs a Schottky Ag0-Ag2S heterojunction on NaYF4:Yb,Tm upconversion nanoparticles. Under NIR excitation, the upconversion core emits visible light that activates the heterojunction, promoting electron-hole separation. The Ag0-Ag2S junction facilitates Type I photochemistry, generating hydroxyl radicals (•OH) via electron transfer to water, independent of molecular oxygen. This contrasts with Type II PDT, which relies on singlet oxygen production from O2. In hypoxic uterine conditions, Type I mechanism ensures sustained ROS generation, as confirmed by electron spin resonance and radical scavenging assays.
How does the scaffold achieve deep tissue penetration for photodynamic activation?
The scaffold incorporates NaYF4:Yb,Tm upconversion nanoparticles that absorb near-infrared (NIR) light (typically 980 nm) and emit visible wavelengths (e.g., 450 nm, 475 nm) via multiphoton upconversion. NIR light penetrates biological tissues significantly deeper than visible light (up to several centimeters vs. <1 mm), enabling activation of the photosensitizer in deep endometrial layers. The study demonstrates effective antibacterial activity through 5 mm thick tissue, whereas visible-light-activated PDT fails beyond 1 mm.
What is the role of Ag+ ion release in the antibacterial mechanism, and how does it complement photodynamic action?
Ag+ ions are released from the Ag0-Ag2S heterojunction over time, providing sustained bactericidal activity. Ag+ disrupts bacterial cell membranes, denatures proteins, and interferes with DNA replication. This complements the rapid ROS burst from PDT, offering both immediate and long-term antibacterial effects. The study shows that the combination of PDT and Ag+ release achieves a >99.9% killing efficiency against Staphylococcus aureus and Escherichia coli, whereas PDT alone achieves ~90% and Ag+ alone ~80% under the same conditions.
How does the scaffold's biodegradability and 3D printing capability impact clinical translation?
The scaffold is fabricated from poly(L-lactic acid) (PLLA) using selective laser sintering (SLS), allowing patient-specific customization of shape and porosity. PLLA degrades into lactic acid, a natural metabolite, over 6-12 months, eliminating the need for surgical removal. In vivo studies in a rat model of endometrial injury show complete scaffold degradation by 12 weeks with new tissue formation, and no chronic inflammation. This reduces patient trauma and secondary infection risk, and the customizable geometry ensures optimal fit for individual uterine cavities.
What are the scalability and cost considerations for manufacturing this scaffold?
SLS is a well-established additive manufacturing technique that can be scaled for clinical production. The raw materials—PLLA, NaYF4:Yb,Tm, ZIF-8, and silver salts—are commercially available at moderate cost. The synthesis of the heterojunction involves a multi-step process but can be batch-produced. Preliminary cost analysis suggests a ~30% increase over conventional PLLA scaffolds, but the elimination of secondary surgery and reduced antibiotic use may offset overall healthcare costs. Further optimization of the synthesis and printing parameters is underway to improve reproducibility and reduce production time.
Related Chinese Research & Cross-Citations
Ammonium Vanadate Cathodes in Aqueous Zinc-Ion Batteries: Design Strategies and Research Progress
Aqueous zinc-ion batteries (AZIBs) offer a compelling combination of high safety, environmental compatibility, and abundant zinc resources, positioning them as viable candidates for grid-scale energy storage. Their practical deployment, however, is constrained by cathode materials that suffer from structural degradation, sluggish Zn2+ diffusion, and inadequate electronic conductivity. Ammonium vanadates (AVOs) have emerged as high-performance cathodes owing to their layered or tunneled frameworks, which accommodate reversible Zn2+ (de)intercalation with diffusion coefficients superior to conventional vanadium oxides. This review systematically examines recent advances in AVO cathodes for AZIBs, correlating morphological variations—including nanowires, nanobelts, and microflowers—with electrochemical characteristics. The analysis establishes structure–performance relationships that govern capacity retention, rate capability, and cycling stability. Key optimization strategies are critically assessed: defect engineering to enhance electronic conductivity and active site density, interlayer spacing modulation via pre-intercalated cations or structural water to facilitate Zn2+ transport, and composite construction with conductive carbonaceous or polymeric matrices to mitigate dissolution and improve mechanical integrity. Despite these advances, challenges persist in achieving long-term cycling stability (>10,000 cycles) and high areal mass loading (>10 mg cm-2) required for commercial viability. The review concludes by outlining future research directions, including operando characterization of degradation mechanisms and scalable synthesis routes for AVO cathodes in practical AZIB configurations.
Microenvironment-responsive therapeutic platforms: Innovations for spinal cord injury repair
Spinal cord injury (SCI) remains a formidable clinical challenge due to the complex, dynamic lesion microenvironment that impedes axonal regeneration and functional recovery. This highlight examines a microenvironment-responsive therapeutic platform integrating microneedle delivery, ferroptosis modulation, and hydrogen therapy. The platform leverages the pathological hallmarks of SCI—oxidative stress, iron dyshomeostasis, and lipid peroxidation—to achieve spatiotemporally controlled cargo release. By combining microneedle arrays for minimally invasive intraparenchymal administration with hydrogen-releasing biomaterials, the system addresses the dual bottlenecks of poor drug penetration across the blood-spinal cord barrier and insufficient neutralization of reactive oxygen species. Ferroptosis inhibition is achieved through iron chelation and glutathione peroxidase 4 (GPX4) stabilization, while hydrogen gas scavenges hydroxyl radicals and peroxynitrite. This multimodal strategy attenuates secondary injury cascades, reduces glial scar formation, and promotes neural stem cell differentiation. The work is supported by the National Natural Science Foundation of China (82574518) and the Talent Cultivation Project of Paring Academicians with Young Talents in higher education institutions in Zhejiang. The authors declare no conflict of interest. This highlight underscores the translational potential of microenvironment-responsive platforms for SCI repair, emphasizing the need for rigorous preclinical validation and scalable manufacturing.
Dual-Site Adsorption over Phosphorus-Doped Copper Oxide for Efficient CO2 Electroreduction to Ethylene
Electroreduction of CO2 to ethylene offers a promising route for renewable electricity storage, yet achieving high ethylene selectivity at industrial current densities remains challenging due to the large energy barrier for C–C coupling. Here, we report a “MOF-assisted in situ doping” strategy to introduce the oxophilic nonmetal phosphorus (P) into the copper oxide (CuO) lattice, constructing a localized Cu–P dual-site adsorption configuration for the key *OCCHO intermediate. The optimized catalyst delivers an impressive Faradaic efficiency of 64.6% for ethylene with a partial current density of 646 mA cm-2. Comprehensive structural characterizations demonstrate that P mainly occupies Cu sites, generating abundant lattice defects and oxygen vacancies. In situ synchrotron infrared spectroscopy and theoretical calculations reveal that P doping modulates the electronic structure of Cu, optimizes the binding energies of *CO and *CHO, and stabilizes *OCCHO via P–O/Cu–C dual-site adsorption, thereby significantly lowering the asymmetric C-C coupling energy barrier to 0.74 eV. This work highlights a dual-site microenvironment regulation strategy for CO2-to-ethylene electroreduction.
Hydrophilic Single-Atom Interface Unlocks Low-Potential CO Removal on Pt in PEMFCs
Proton exchange membrane fuel cells (PEMFCs) fed with reformate hydrogen suffer severe anode poisoning by trace CO, necessitating high CO electrooxidation potentials that degrade performance and durability. This work introduces a Pt@CrSA-N-C anode catalyst featuring a hydrophilic Cr single-atom interface that simultaneously weakens CO adsorption on Pt via electronic regulation and promotes water activation, thereby lowering the CO oxidation onset potential to approximately 0.13 V vs. RHE. The onset potential was determined by two independent methods: the first potential at which the background-corrected current exceeds 0 mA cm-2 during CO oxidation reaction tests in a three-electrode system, and the potential at which the forward scan current exceeds the N2 background current in CO-stripping voltammetry. The catalyst achieves a maximum power density under 100 ppm CO that surpasses reported advanced catalysts, as compiled in Table S5. Structural, spectroscopic, and electrochemical characterizations collectively establish a coherent rationale for the hydrophilic single-atom interface strategy. This approach addresses the longstanding trade-off between CO tolerance and Pt utilization, offering a viable route for low-potential CO removal in practical PEMFC anodes.
An Ionoelastomer-Based Bioinspired Wearable Electronics with Tele-Perception and Tactile Sensation for Machine Learning-Assisted Rehabilitation Management
Comprehensive assessment of rehabilitation efficiency is essential for designing appropriate training programs for better musculoskeletal functional recovery. Existing contact-receptor-dependent rehabilitation assessment systems mostly focus on assessing the restoration of muscle function by evaluating grip strength or joint flexion angle; however, parameters reflecting neuromuscular synergistic function are always overlooked. Herein, we develop an ionoelastomer-based soft artificial electroreceptor (SAER) that integrates tele-perception and tactile sensation to track the rehabilitation process, collecting signals related to approaching speed and grip strength sequentially. The SAER uses polyurethane ionoelastomer incorporated with quasi-solid conductive salt as the electric field receptor, and is integrated on a rehabilitation-training ball after assembly to establish an untethered detection device; this enables the remote capture of hand approaching parameter within a 9 cm range, followed by the quantification of grip strength when contacting and grasping. Furthermore, a data-driven assessment system is established by integrating machine learning, which accurately classifies rehabilitation efficiency into six levels; it supports for rehabilitation evaluation and training programs adjustment. Overall, the SAER-based rehabilitation management system establishes a paradigm that synergistically evaluating parameters corresponding to neuromuscular functional restoration and holds strong potential for home-based active rehabilitation for minimizing dependence on frequent clinical supervision.
Microwave-Absorbing Materials with Strong Environmental Adaptability for Corrosion Protection, Anti-Icing, and Thermal Management
Microwave-absorbing materials (MAMs) deployed on naval vessels, aerospace vehicles, and critical electronic systems face coupled electromagnetic, marine salt-spray corrosion, and extreme-temperature loads that legacy single-function absorbers cannot withstand. This review consolidates progress on three environmentally adaptive MAM classes: corrosion-protective, anti-icing, and thermal-management absorbers. The electromagnetic loss and impedance-matching fundamentals are first established, then the synergistic mechanisms, design strategies, and characterization protocols for each class are examined against representative material systems and their measured performance. The analysis identifies a shared design logic—multiscale hierarchical architecture, interfacial polarization engineering, and multifunctional phase integration—while distinguishing the divergent protection mechanisms: barrier and passivation effects for corrosion, surface-energy and latent-heat regulation for anti-icing, and phonon–electron transport decoupling for thermal management. Persistent bottlenecks include the trade-off between impedance matching and protective-layer density, the absence of standardized coupled-field test protocols, and the scarcity of long-term salt-spray and thermal-cycling durability data. Future directions are delineated: intelligent self-adaptive absorbers, multiphysics-coupled simulation frameworks, and environmentally benign multifunctional integration. The review provides a theoretical and technical basis for the design, construction, and engineering scale-up of next-generation high-performance absorbers for aerospace, electronic, and marine equipment.