Key Takeaways & Executive Findings
- •• • Yb3+/Ho3+ co-doped UCNPs exhibit spontaneous blinking with negligible photodegradation under 976 nm CW excitation, enabling prolonged SMLM without photobleaching—critical for long-term dynamic studies. • • Kinetic analysis shows single-exponential bright-state dwell times and biexponential dark-state dwell times, indicating one decay pathway into a non-emissive state and two recovery pathways—essential for optimizing blinking kinetics. • • In fixed cells, FRC resolution reached 30 nm, confirming sub-50 nm performance in biological specimens—meeting the resolution requirements for super-resolution imaging. • • Live-cell imaging demonstrated synchronized transport of UCNPs with near-unity positional correlation and minimal relative velocities—enabling precise tracking of intercellular dynamics.
Abstract
Single-molecule localization microscopy (SMLM) surpasses the diffraction limit to achieve molecular-scale resolution, but conventional probes suffer from photobleaching, limiting imaging duration. In a recent Nature Photonics article, Ren and co-workers introduced spontaneous photoblinking upconversion microscopy (SPUM) using Yb3+/Ho3+ co-doped core–shell–shell upconversion nanoparticles (UCNPs, NaYF4@NaYb/HoF4@NaLuF4). These UCNPs exhibit exceptional photostability and persistent, reversible blinking under 976 nm continuous-wave excitation, with negligible photodegradation. The blinking mechanism involves a Yb3+ multiphoton process coupled with defect-mediated energy trapping, switching the UCNPs between emissive (on) and non-emissive (off) states. Kinetic analysis revealed single-exponential bright-state dwell times and biexponential dark-state dwell times, indicating one decay pathway into a non-emissive state and two recovery pathways. In live-cell imaging, synchronized transport of UCNPs maintained constant interparticle distance and near-unity positional correlation. In fixed cells, Fourier ring correlation (FRC) resolution reached 30 nm, confirming sub-50 nm performance in biological specimens. This work provides an unprecedented combination of low duty cycle and photostability, establishing a foundation for non-photobleaching luminescent nanomaterials in long-term super-resolution imaging and nanoscale tracking.
1. Introduction
Conventional SMLM relies on organic dyes and fluorescent proteins that suffer from photobleaching, restricting imaging duration and performance. This limitation hampers long-term observation of dynamic biological processes, as probes lose fluorescence within minutes, preventing high-precision localization over extended periods. The need for photostable probes with controllable blinking is critical for advancing super-resolution microscopy in live-cell applications.
Ren and co-workers address this bottleneck by introducing Yb3+/Ho3+ co-doped UCNPs that exhibit spontaneous, persistent blinking under 976 nm excitation without photodegradation. Their defect-mediated energy-trapping mechanism provides a low duty cycle and exceptional photostability, enabling long-term, high-precision single-molecule localization. This innovation overcomes the photobleaching barrier, offering a new class of probes for dynamic super-resolution imaging.
Loading authentic research manuscript (Pages 1–5)...
DONG Yihong, HUANG Ping, CHEN Xueyuan (2026). Photoblinking upconversion nanoparticles for super-resolution imaging. SCIENCE CHINA Materials. https://doi.org/10.1007/s40843-026-4376-3
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 photostability of the UCNPs under continuous 976 nm excitation, and how does it compare to organic dyes?
The UCNPs exhibit negligible photodegradation under 976 nm CW excitation, whereas organic dyes typically photobleach within minutes. This allows prolonged imaging without signal loss, essential for long-term tracking.
What are the kinetic parameters of the blinking behavior, and how do they affect localization precision?
Bright-state dwell times follow a single-exponential distribution, while dark-state dwell times are biexponential, indicating one decay pathway and two recovery pathways. This kinetics enables a low duty cycle, reducing overlap of point spread functions and improving localization precision.
How does the defect-mediated energy-trapping mechanism control the on/off switching?
Under 976 nm excitation, Yb3+ ions undergo multiphoton energy transfer to form a defect-mediated energy trap, which suppresses energy transfer to Ho3+, switching the UCNP to an off state. Recovery of the trap reinstates emission, enabling reversible blinking.
What is the achieved spatial resolution in biological specimens, and how was it measured?
In fixed cells, Fourier ring correlation (FRC) analysis yielded a resolution of 30 nm, confirming sub-50 nm performance. This was achieved by reducing motion and allowing longer acquisition times.
Can these UCNPs be used for live-cell imaging without cytotoxic effects?
The study demonstrates live-cell imaging with synchronized transport of UCNPs, indicating biocompatibility. However, detailed cytotoxicity assays are not provided in the highlight; further studies would be needed to confirm long-term biocompatibility.
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.