Near-infrared Research Articles

Coupling Gold Nanospheres into Nanochain Constructs for High-Contrast, Longitudinal Photoacoustic Imaging.

Structural parameters play a crucial role in determining the electromagnetic and thermal responses of gold nanoconstructs (GNCs) at near-infrared (NIR) wavelengths. Therefore, developing GNCs for reliable, high-contrast photoacoustic imaging has been focused on adjusting structural parameters to achieve robust NIR light absorption with photostability. In this study, we introduce an efficient photoacoustic imaging contrast agent: gold sphere chains (GSCs) consisting of plasmonically coupled gold nanospheres. The chain geometry results in enhanced photoacoustic signal generation originating from outstanding photothermal characteristics compared to traditional gold contrast agents, such as gold nanorods. Furthermore, the GSCs produce consistent photoacoustic signals at laser fluences within the limits set by the American National Standards Institute. The exceptional photoacoustic response of GSCs allows for high-contrast photoacoustic imaging over multiple imaging sessions. Finally, we demonstrate the utility of our GSCs for molecular photoacoustic cancer imaging, both in vitro and in vivo, through the integration of a tumor-targeting moiety.

Understanding changes of laser backscattering imaging parameters through the kiwifruit softening process using time series analysis

ABSTRACT During kiwifruit storage, quality monitoring is required for inventory planning and consistent quality maintenance. Commercial near-infrared (NIR) spectrophotometers showed reduced performance in the estimation of kiwifruit flesh firmness (FF) as the FF estimation is indirect and can be affected when both, textural structures and absorbing compounds, change during postharvest ripening. Laser backscattering imaging (LBI) records the backscattered signal after a single laser beam interacts with kiwifruit tissue, including merged information on light absorption and scattering. Measurements were carried out at 830 nm, where scattering is most dominant. In this work, time series of kiwifruit ‘Zesy002’ (n = 30) and ‘Hayward’ (n = 30) LBI were collected through the postharvest ripening during a 15-day shelf life at 20°C. Four LBI parameters capturing DIP, FWHM, SLP and HWQM were selected in this study. ‘‘Zesy002’ DIP, FWHM, SLP, and HWQM increased approx. 0.6 cm, 0.2 cm, 0.3 and 0.14 cm, respectively. ‘Hayward’ LBI increased approx. 0.2 cm, 0.1 cm, 0.2 and 0.04 cm, respectively. Different initial LBI values between cultivars and LBI changes may reflect the actual stage of softening, affected by kiwifruit ripeness. In conclusion, time series analysis could be useful in describing kiwifruit LBI change during ripening and making forecasts.

Improved broadband luminescence in Gd2GaSb1-xTaxO7:Cr3+,Yb3+ pyrochlore phosphors: Near-infrared spectroscopic applications and dual-mode optical thermometry

The growing demand for spectroscopic applications in the fields of night vision monitoring, non-destructive analysis and bioimaging has led to extensive research into near infrared (NIR) light sources. Thus, the design of high-performance broadband Cr3+-doped NIR phosphors is of urgent and critical importance. Herein, novel Gd2GaSb1-xTaxO7:Cr3+,Yb3+ NIR-emitting pyrochlore phosphors were successfully explored. Via partly substituting Sb5+ by Ta5+ and tuning Cr3+ amount, a significant enhancement, broadening and redshift of Cr3+ NIR luminescence are exhibited under the radiation of 460 nm light. Moreover, higher thermal stability and wider NIR luminescence are realized by the proper introduction of Yb3+. A satisfactory NIR output power of 46.51 mW @ 300 mA and photoelectric efficiency of 10.82 % @ 10 mA of the fabricated NIR phosphor-converted light-emitting diodes (NIR pc-LEDs) based on Gd1.96Ga0.97Sb0.9Ta0.1O7:3%Cr3+,4%Yb3+ phosphor enable the demonstration in night vision and bioimaging applications. Besides, superior dual-mode optical thermometry was successfully constructed on fluorescence intensity ratio (Cr3+/Yb3+) and fluorescence lifetime (4T2) of Cr3+ in Gd2GaSb1-xTaxO7:Cr3+,Yb3+. These results confirm that Gd2GaSb1-xTaxO7:Cr3+,Yb3+ can serve as inspiring luminescent converters employed in NIR pc-LEDs and non-contact temperature sensing.

Electronic Structure of Metallophlorins: Lessons from Iridium and Gold Phlorin Derivatives.

Phlorins have long remained underexplored relative to their fully conjugated counterparts, such as porphyrins, hydroporphyrins, and corroles. Herein, we have attempted to bridge that knowledge gap with a scalar-relativistic density functional theory (DFT) study of unsubstituted iridium and gold phlorin derivatives and a multitechnique experimental study of iridium-bispyridine and gold complexes of 5,5-dimethyl-10,15,20-tris(pentafluorophenyl)phlorin. Theory and experiments concur that the phlorin derivatives exhibit substantially smaller HOMO-LUMO gaps, as reflected in a variety of observable properties. Thus, the experimentally studied Ir and Au complexes absorb strongly in the near-infrared (NIR), with absorption maxima at 806 and 770 nm, respectively. The two complexes are also weakly phosphorescent with emission maxima at 950 and 967 nm, respectively. They were also found to photosensitize singlet oxygen formation, with quantum yields of 40 and 28%, respectively. The near-infrared (NIR) absorption and emission are consonants with smaller electrochemical HOMO-LUMO gaps of ∼1.6 V, compared to values of ∼2.1 V, for electronically innocent porphyrins and corroles. Interestingly, both the first oxidation and reduction potentials of the Ir complex are some 600 mV shifted to more negative potentials relative to those of the Au complex, indicating an exceptionally electron-rich macrocycle in the case of the Ir complex.

A Processible and Ultrahigh-temperature Organic Photothermal Material through Spontaneous and Quantitative [2+2] Cycloaddition-Cycloreversion.

Energy conversion, particularly light to heat conversion, has garnered significant attention owing to its prospect in renewable energy exploitation and utilization. Most previous efforts have focused on developing organic photothermal materials for low-temperature applications, whereas the importance of simplifying the preparation methods of photothermal materials and enhancing their maximum photothermal temperature have been less taken. Herein, we prepare an organic near-infrared (NIR) photothermal material namely ATT by a spontaneous [2+2] cycloaddition-cycloreversion reaction. In addition to the solution-based method, ATT could also be readily preapred by ball milling in a high yield of 90% in just 15 min. ATT powder exhibits a broad absorption extending beyond 2000 nm, excellent processability, and thermal stability. Remarkably, ATT powder can reach an unprecedently temperature as high as 450 °C while maintaining excellent photostability upon photoirradiation. Leveraging its extraordinary photothermal and processable properties, ATT was used in the high-temperature applications, such as photo-ignition, photo-controlled metal processing and high-temperature shape memory, all of which offer spatiotemporal control capabilities. This work provides a new approach to prepare organic photothermal materials with high temperatures, and pave the way for their applications in extreme environments.

Development and optimisation of a Near-Infrared spectroscopic system for glucose quantification in aqueous and intralipid-based samples

Abstract A non-invasive glucose sensing device could revolutionise diabetes treatment. Near Infrared (NIR) spectroscopy is a promising technology for glucose sensing; however, the design and choice of components for NIR spectroscopy can greatly affect the sensing accuracy. We aimed to develop a NIR absorption spectroscopy system to determine liquid glucose concentrations in the physiological range, by evaluating a range of NIR photodetector components and light sources. Three detection assemblies were tested: (i) a dispersive spectrometer with photodiode array, (ii) a Czerny-Turner monochromator with InGaAs photodiode and (iii) a miniature Fourier Transform Infrared (FTIR) spectrometer. A halogen lamp and NIR globar were trialled as potential light sources. The components were systematically tested by comparing the coefficient of determination and standard error of prediction (SEP) for the same set of aqueous glucose samples through 10 mmol/L concentration steps. The Czerny-Turner monochromator with InGaAs photodiode, along with the globar, were identified as the optimal components for the system. A range of concentration steps (1-10 mmol/L) were scanned to identify the physiologically relevant limit of detection, which was identified as 5mmol/L for glucose in solution. Spectra were then collected from glucose samples in 10% intralipid suspension in the 10-20 mmol/L range and the equivalent concentrations in solution. The SEP was greater for the intralipid samples due to strong scattering. Scattering was dominant above 1300nm, whilst absorption was dominant below 1300nm. Although alternative approaches achieve better resolution, our system uses simple and readily-available components and presents a platform for a non-invasive NIR glucose sensing device.

3D drift correction for super-resolution imaging with a single laser light.

Single-molecule localization microscopy (SMLM) enables three-dimensional (3D) super-resolution imaging of nanoscale structures within biological samples. However, prolonged acquisition introduces a drift between the sample and the imaging system, resulting in artifacts in the reconstructed super-resolution image. Here, we present a novel, to our knowledge, 3D drift correction method that utilizes both the reflected and scattered light from the sample. Our method employs the reflected light of a near-infrared (NIR) laser for focus stabilization while synchronously capturing speckle images to estimate the lateral drift. This approach combines high-precision active compensation in the axial direction with lateral post-processing compensation, achieving the abilities of 3D drift correction with a single laser light. Compared to the popular localization events-based cross correlation method, our approach is much more robust, especially for datasets with sparse localization points.

A Light Emitting Device with TiO2:Er3+/ZnO Heterostructure for Enhanced Near-Infrared Electroluminescence

Abstract Near-infrared (NIR) electroluminescence (EL) devices based on Er3+ ions doped TiO2 emitting layer have been fabricated by employing a facile sol-gel method. The effect of Er3+ ion doping concentration on the EL performance of TiO2:Er3+ thin film devices was investigated. Moreover, a novel device with the core of TiO2:1%Er3+/ZnO heterostructure was designed and fabricated. The EL performance of the device with optimized Er3+ ion doping concentration and improved structure was significantly improved. The NIR EL-enabling voltage of the improved device is as low as ~5 V. The attenuated concentration quenching effect and the ZnO film as an electron blocking layer should contribute to the improved EL performance of the optimized device.

Dynamic Near‐Infrared Circularly Polarized Luminescence Encoded by Transient Supramolecular Chiral Assemblies

Circularly polarized luminescence (CPL) is promising for applications in many fields. However, most systems involving CPL are within the visible range; near‒infrared (NIR) CPL‒active materials, especially those that exhibit high glum values and can be controlled spatially and temporally, are rare. Herein, dynamic NIR‒CPL with a glum value of 2.5[[EQUATION]]10‒2 was achieved through supramolecular coassembly and energy transfer strategies. The chiral assemblies formed by the coassembly between adenosine triphosphate (ATP) and a pyrene derivative exhibit a red CPL signal (glum of 10‒3). The further introduction of sulfo‒cyanine5 resulted in a cooperative energy transfer process, which not only aroused the NIR CPL but also increased the glum value to 10‒2. Temporal control of these chiral assemblies was realized by introducing alkaline phosphatase to fabricate a biomimetic enzyme‒catalyzed network, allowing the dynamic NIR CPL signal to be turned on. Based on these enzyme‐regulated temporally controllable dynamic CPL‐active chiral assemblies, a multilevel information encryption system was further developed. Our work provides a pioneering example for constructing dynamic NIR CPL materials holding the ability to perform temporal control via the supramolecular assembly strategy, which is expected to aid in the design of supramolecular complex systems that more closely resemble natural biological systems.

Dynamic Near-Infrared Circularly Polarized Luminescence Encoded by Transient Supramolecular Chiral Assemblies.

Circularly polarized luminescence (CPL) is promising for applications in many fields. However, most systems involving CPL are within the visible range; near‒infrared (NIR) CPL‒active materials, especially those that exhibit high glum values and can be controlled spatially and temporally, are rare. Herein, dynamic NIR‒CPL with a glum value of 2.5[[EQUATION]]10‒2 was achieved through supramolecular coassembly and energy transfer strategies. The chiral assemblies formed by the coassembly between adenosine triphosphate (ATP) and a pyrene derivative exhibit a red CPL signal (glum of 10‒3). The further introduction of sulfo‒cyanine5 resulted in a cooperative energy transfer process, which not only aroused the NIR CPL but also increased the glum value to 10‒2. Temporal control of these chiral assemblies was realized by introducing alkaline phosphatase to fabricate a biomimetic enzyme‒catalyzed network, allowing the dynamic NIR CPL signal to be turned on. Based on these enzyme-regulated temporally controllable dynamic CPL-active chiral assemblies, a multilevel information encryption system was further developed. Our work provides a pioneering example for constructing dynamic NIR CPL materials holding the ability to perform temporal control via the supramolecular assembly strategy, which is expected to aid in the design of supramolecular complex systems that more closely resemble natural biological systems.

Ternary heterostructure-driven photoinduced electron-hole separation enhanced oxidative stress for triple-negative breast cancer therapy

Zinc oxide nanoparticles (ZnO NPs) stand as among the most significant metal oxide nanoparticles in trigger the formation of reactive oxygen species (ROS) and induce apoptosis. Nevertheless, the utilization of ZnO NPs has been limited by the shallowness of short-wavelength light and the constrained production of ROS. To overcome these limitations, a strategy involves achieving a red shift towards the near-infrared (NIR) light spectrum, promoting the separation and restraining the recombination of electron-hole (e−-h+) pairs. Herein, the hybrid plasmonic system Au@ZnO (AZ) with graphene quantum dots (GQDs) doping (AZG) nano heterostructures is rationally designed for optimal NIR-driven cancer treatment. Significantly, a multifold increase in ROS generation can be achieved through the following creative initiatives: (i) plasmonic Au nanorods expands the photocatalytic capabilities of AZG into the NIR domain, offering a foundation for NIR-induced ROS generation for clinical utilization; (ii) elaborate design of mesoporous core-shell AZ structures facilitates the redistribution of electron-hole pairs; (iii) the incorporation GQDs in mesoporous structure could efficiently restrain the recombination of the e−-h+ pairs; (iv) Modification of hyaluronic acid (HA) can enhance CD44 receptor mediated targeted triple-negative breast cancer (TNBC). In addition, the introduced Au NRs present as catalysts for enhancing photothermal therapy (PTT), effectively inducing apoptosis in tumor cells. The resulting HA-modified AZG (AZGH) exhibits efficient hot electron injection and e−-h+ separation, affording unparalleled convenience for ROS production and enabling NIR-induced PDT for the cancer treanment. As a result, our well-designed mesoporous core-shell AZGH hybrid as photosensitizers can exhibit excellent PDT efficacy.

Atto-Scale Noise Near-Infrared Organic Photodetectors Enabled by Controlling Interfacial Energetic Offset through Enhanced Anchoring Ability.

The near-infrared (NIR) sensor technology is crucial for various applications such as autonomous driving and biometric tracking. Silicon photodetectors (SiPDs) are widely used in NIR applications; however, their scalability is limited by their crystalline properties. Organic photodetectors (OPDs) have attracted attention for NIR applications owing to their scalability, low-temperature processing, and notably low dark current density (JD), which is similar to that of SiPDs. However, the still high JD (at NIR band) and few measurements of noise equivalent powers (NEPs) pose challenges for accurate performance comparisons. This study addresses these issues by quantitatively characterizing the performance matrix and JD generation mechanism using electron-blocking layers (EBLs) in OPDs. The energy offset at an EBL/photosensitive layer interface determines the thermal activation energy and directly affects JD. A newly synthesized EBL (3PAFBr) substantially enhances the interfacial energy barrier by forming a homogeneous contact owing to the improved anchoring ability of 3PAFBr. As a result, the OPD with 3PAFBr yields a noise current of 852 aA (JD = 12.3 fAcm⁻2 at V → -0.1V) and several femtowatt-scale NEPs. As far as it is known, this is an ultralow ofJD in NIR OPDs. This emphasizes the necessity for quantitative performance characterization.

Near-Infrared Luminescent Materials Incorporating Rare Earth/Transition Metal Ions: From Materials to Applications.

Near-infrared materials exhibiting high photoluminescence quantum yields present a promising avenue to broaden our capacity and threshold for detection and manipulation, extending beyond the visible emission range. The spotlight has shifted to near-infrared (NIR) luminescent materials emitting beyond 1000nm, with growing interest due to their unique characteristics. The ability of NIR-II emission (1000-1700nm) to penetrate deeply and transmit independently positions these NIR luminescent materials for applications in optical-communication devices, bioimaging, and photodetectors. The combination of rare earth metals/transition metals with a variety of matrix materials provides a new platform for creating new chemical and physical properties for materials science and device applications. In this review, we summarize the recent advancements in NIR emission activated by rare earth and transition metal ions and illustrate their role in applications spanning bioimaging, sensing, and optoelectronics. We start from the various synthesis techniques, including high-temperature solid-state, hydrothermal, and thermal decomposition methods, on how to delicately incorporate the rare-earth/transition metals to the NIR various matrixes, each imparting distinct characteristics to these luminescent materials. We then extend the discussion to strategies of enhancing excitation absorption and emission efficiency, spotlighting innovations like dye sensitization and surface plasmon resonance effects. Subsequently, a significant focus is placed on functionalization strategies and their applications. Finally, we provide a comprehensive analysis of the challenges and proposed strategies for rare earth/transition metal ion-doped near-infrared luminescent materials, summarizing the insights of each section. This article is protected by copyright. All rights reserved.

Near-Infrared Absorbing Aza-BODIPY Dyes for Optoelectronic Applications.

Organic dyes that absorb light in the visible to near-infrared region have garnered significant interest, owing to their extensive utility in organic photovoltaics and various biomedical applications. Aza-boron-dipyrromethene (Aza-BODIPY) dyes are a class of chromophores with impressive photophysical properties such as tunable absorption from the visible region towards near infrared (NIR) region, high molar absorptivity, and fluorescence quantum yield. In this review, we discuss the developments in the aza-BODIPYs, related to their synthetic routes, photophysical properties and their applications. Their design strategies, modifications in chemical structures, mode/position of attachment, and their impact on photo-physical properties are reviewed. The potential applications of aza-BODIPY derivatives such as organic solar cells, photodynamic therapy, boron-neutron capture therapy, fluorescence sensors, photo-redox catalysis, photoacoustic probes and optoelectronic devices are explained.

Versatile Biomass‐Based Injectable Photothermal Hydrogel for Integrated Regenerative Wound Healing and Skin Bioelectronics

AbstractThe continuously growing utilization of wound healing materials and skin bioelectronics urges the development of flexible hydrogels for personal therapy and health management. Versatile conductive hydrogels prepared from natural biomass are ideal candidates as one of the promising solutions for chronic wound management. Here, the study proposes a kind of robust (strain: 1560.8%), adhesive, self‐healing, injectable, antibacterial (sterilization rate: 99%), near‐infrared (NIR) photothermal responsive, biocompatible, and conductive hydrogel (CPPFe@TA) composed of carboxymethyl cellulose and tannic acid/iron ion complex (TA@Fe3+), featuring rapid self‐assembly and tunable crosslinking time. TA@Fe3+ facilitated the self‐catalysis of the polymerization reaction, and the crosslinking time could be controlled by adjusting Fe3+ concentration. Under NIR irradiation, the hydrogel exhibited remarkable photothermal antibacterial performance. In the full‐thickness skin defect repair experiment on mice, the prepared hydrogel dressing significantly enhanced wound healing. After 14 days, the wound healing rate (95.49%) of CPPFe@TA3 hydrogel + NIR treatment greatly exceeded that of commercial dressings. Meanwhile, the hydrogels has good electrical conductivity and thermo‐responsiveness, making them promising for skin bioelectronics in physiological signal monitoring and rehabilitation exercise management. This work therefore offers a promising strategy for developing versatile biomass‐based hydrogels, which is expected to be applicable to integrated regenerative wound healing and skin bioelectronics.

Modeling Forest Above-Ground Biomass of Teak (Tectona grandis L. F.) Using Field Measurement and Sentinel-2 Imagery

Over the last few decades, remote sensing has emerged as a dependable and cost-effective method for collecting precise data on forest biophysical parameters, aiding in sustainable forest management and global initiatives to combat climate change. This research aimed to develop a model for estimating the above-ground biomass (AGB) of Teak (Tectona grandis L. F.) by combining field measurements with Sentinel-2 earth observation data. The study took place in 36-year-old teak plantation areas within the Sagarnath Forest Development Project in Nepal’s Sarlahi district. Field measurements were conducted using a destructive systematic sampling method, employing 10 × 10 m2 sample plots, and the volume of logs was determined using Newton’s formula. A total of 30 sample plots were used for calibration, while 10 were utilized for validation purposes. The findings revealed that the average AGB per plot was 814 kg (equivalent to 81.4 t ha−1), with a minimum value of 716 kg (71.6 t ha−1) and a maximum value of 1,060 kg (106 t ha−1). The study utilized five independent variables, namely, the Red band, Green band, Blue band, near-infrared (NIR), and normalized difference vegetation index (NDVI) values from Sentinel-2 imagery data, to develop estimation models. Among the 12 models examined, model M10 proved to be the best fit for accurate AGB estimation (adjusted R2 = 0.9809, RMSE = 0.01269, AIC = −170, and p-value = < 8.39e−21). The equation of the best-fitted model was ln (AGB) = A + B × Red + C × Green + D × Blue2 + E × ln (NIR) + F × ln (NDVI), providing an accurate estimate of AGB. Model validation involved a t-test comparing the observed and calculated AGB values for ten sample plots, demonstrating no significant difference (p-value = 0.3662 > 0.05). This model has the potential to facilitate AGB biomass calculations and carbon stock estimates for teak plantations of similar age groups.

Bioinspired Bone Seed 3D‐Printed Scaffold via Trapping Black Phosphorus Nanosheet for Bone Regeneration

Significance of endogenous mineralization in bone reconstruction is paramount, as it facilitates the accumulation of calcium ions for bone tissue deposition. However, conventional 3D‐printed scaffolds lack the capacity for calcium ion enrichment and mineralization, coupled with their low bone inductive activity. Inspired from the development of natural plant seeds, a biomimetic 3D printing scaffold is developed by implanting photosensitive black phosphorus “bone seeds” (BS), guiding a sequential process mirroring rooting (osteoblast recruitment), sprouting (fibrous callus mineralization), flowering (osseous callus formation), and fruiting (callus plasticity). BS were trapped onto porous 3D polycaprolactone (PCL) scaffolds with aminated surfaces via electrostatic interactions between phosphates and amino groups, creating the PCL‐BS scaffold that can actively capture calcium ions for accelerating the endogenous regeneration of critical bone defects. In vitro and in vivo experiments show that the PCL‐BS scaffold has good biocompatibility and strong osteogenic ability for rapid new bone regeneration under near‐infrared (NIR) stimulation. In addition, whole transcriptome sequencing analysis is performed to reveal the transcriptomic mechanism of BS involved in signal transduction and network regulation during bone regeneration. This NIR light‐regulated biomimetic BS inspired by seed planting, introduces a pioneering concept in the design of 3D printing bone repair scaffolds.

Maximization of cytochrome C oxidase enzyme activity by optimizing color conversion from red organic light-emitting diodes

Photobiomodulation (PBM) therapy using red and near-infrared (NIR) light can effectively activate cytochrome C oxidase (CCO) enzyme to promote wound healing in living organisms. To maximize this therapeutic effect, the use of a light source with a spectrum absorbed by the CCO enzyme is necessary. A red/NIR light source optimized for CCO enzyme was obtained by partially color-converting a red organic light-emitting diode with copper indium sulfide/zinc sulfide quantum dots (QDs). To increase color conversion efficiency, the dispersion of QDs was improved by using a fibrous color conversion layer (FCCL). By optimizing the QD content in the FCCL, a red/NIR light source similar to the absorption spectrum of CCO enzyme was obtained with a spectral matching ratio of 81.7 %. When this light source was used in PBM therapy, it was experimentally verified that it showed a much faster wound closure effect compared to general red light, and it was proven that this was due to increased activity of the CCO enzyme. This study is a method of obtaining a red/NIR light source for PBM suitable for a specific enzyme performing a specific function, and is particularly useful due to its excellent form factor of being large, thin, and flexible.

An upconverted afterglow color conversion strategy for in-situ activated persistent luminescent imaging of medical implants

Upconverted afterglow imaging presents a promising avenue for long-term auto-fluorescence-free imaging applications without the necessity of expensive time-resolved equipment. In this research, inspired by LED design, we devised a straightforward ternary upconverted afterglow conversion (UAC) strategy that amalgamates upconversion NaYbF4: Tm0.005 (UP), afterglow ZnS:Cu,Co (AP), and color conversion CaAlSiN3:Eu phosphors (CP). This fusion resulted in a UAC composite that displays a deep-red to near-infrared (NIR) afterglow with a peak at 663 nm, following a brief activation period by 980 nm light. Importantly, an enhancement of 116 times was realized by using the UAC strategy when comparing with a typical single phase afterglow phosphor, Zn3Ga2SnO8:Cr,Yb,Er. The NIR-rechargeable afterglow sustained for a minimum of 100 min after a mere 3 s of NIR wireless charging process and is chemically stable. This makes it highly suitable for long-term luminescence imaging applications. To demonstrate its potential, we employed our ternary UAC phosphor to image medical plastic prostheses through pig skin in vitro and simulated a plastic surgery on a mouse model in vivo. Such luminescent information could prove invaluable for planning future surgical interventions, such as prosthesis replacement, removal, or necessary debris cleaning.

Near-infrared light-driven lab-on-paper cathodic photoelectrochemical aptasensing for di(2-ethylhexyl)phthalate based on AgInS2/Cu2O/FeOOH photocathode

Di(2-ethylhexyl)phthalate (DEHP) is commonly released from plastics in aqueous environment, which can disrupt endocrine system and cause adverse effects on public health. There is a pressing need to highly sensitive detect DEHP. Herein, a near-infrared (NIR) light-driven lab-on-paper cathodic photoelectrochemical aptasensing platform integrated with AgInS2/Cu2O/FeOOH photocathode and “Y”-like ternary conjugated DNA nanostructure-mediated “ON-OFF” catalytic switching of hemin monomer-to-dimer was established for ultrasensitive DEHP detection. Profiting from the collaborative roles of the effective photosensitization of NIR-response AgInS2 and the fast hole extraction of FeOOH, the NIR light-activated AgInS2/Cu2O/FeOOH photocathode generated a markedly enhanced photocathodic signal. The dual hemin-labelled “Y”-like ternary conjugated DNA nanostructures made the hemin monomers separated in space and they maintained highly active to catalyze in situ generation of electron acceptors (O2). The hemin monomers were relocated in close proximity with the help of target-induced allosteric change of DNA nanostructures, which could spontaneously dimerize into catalytically inactive hemin dimers and fail to mediate electron acceptors generation, resulting in a decreased photocathodic signal. Therefore, the ultrasensitive DEHP detection was realized with a linear response range of 1 pM–500 nM and a detection limit of 0.39 pM. This work rendered a promising prototype to construct powerful paper-based photocathodic aptasensing system for sensitive and accurate screening of DEHP in aqueous environment.