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Strong pH-Dependent Near-Infrared Fluorescence in a Microbial Rhodopsin Reconstituted with a Red-Shifting Retinal Analogue
摘要： Near-infrared (NIR)-driven rhodopsins are of great interest in optogenetics and other optobiotechnological developments such as artificial photosynthesis and deep-tissue voltage imaging. Here we report the proton pump proteorhodopsin (PR) containing a NIR-active retinal analogue (PR:MMAR) exhibits intense NIR fluorescence at a quantum yield of 3.3%. This is 130 times higher than native PR (Lenz, M. O.; et al. Biophys J. 2006, 91, 255?262) and 3?8 times higher than the QuasAr and PROPS voltage sensors (Kralj, J.; et al. Science 2011, 333, 345?348; Hochbaum, D. R.; et al. Nat. Methods 2014, 11, 825?833). The NIR fluorescence strongly depends on the pH in the range of 6?8.5, suggesting potential application of MMAR-binding proteins as ultrasensitive NIR-driven pH and/or voltage sensors. Femtosecond transient absorption spectroscopy showed that upon near-IR excitation, PR:MMAR features an unusually long fluorescence lifetime of 310 ps and the absence of isomerized photoproducts, consistent with the high fluorescence quantum yield. Stimulated Raman analysis indicates that the NIR-absorbing species develops upon protonation of a conserved aspartate, which promotes charge delocalization and bond length leveling due to an additional methylamino group in MMAR, in essence providing a secondary protonated Schiff base. This results in much smaller bond length alteration along the conjugated backbone, thereby conferring significant single-bond character to the C13C14 bond and structural deformation of the chromophore, which interferes with photoinduced isomerization and extends the lifetime for fluorescence. Hence, our studies allow for a molecular understanding of the relation between absorption/emission wavelength, isomerization, and fluorescence in PR:MMAR. As acidification enhances the resonance state, this explains the strong pH dependence of the NIR emission.
关键词： stimulated Raman analysis,fluorescence,voltage sensor,rhodopsins,optogenetics,artificial photosynthesis,proteorhodopsin,femtosecond transient absorption spectroscopy,pH sensor,Near-infrared,voltage imaging
更新于2025-09-23 15:21:01
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Impact of Stokes Shift on the Performance of Near-Infrared Harvesting Transparent Luminescent Solar Concentrators
摘要： Visibly transparent luminescent solar concentrators (TLSC) have the potential to turn existing infrastructures into net-zero-energy buildings. However, the reabsorption loss currently limits the device performance and scalability. This loss is typically defined by the Stokes shift between the absorption and emission spectra of luminophores. In this work, the Stokes shifts (SS) of near-infrared selective-harvesting cyanines are altered by substitution of the central methine carbon with dialkylamines. We demonstrate varying SS with values over 80 nm and ideal infrared-visible absorption cutoffs. The corresponding TLSC with such modification shows a power conversion efficiency (PCE) of 0.4% for a >25 cm2 device area with excellent visible transparency >80% and up to 0.6% PCE over smaller areas. However, experiments and simulations show that it is not the Stokes shift that is critical, but the total degree of overlap that depends on the shape of the absorption tails. We show with a series of SS-modulated cyanine dyes that the SS is not necessarily correlated to improvements in performance or scalability. Accordingly, we define a new parameter, the overlap integral, to sensitively correlate reabsorption losses in any LSC. In deriving this parameter, new approaches to improve the scalability and performance are discussed to fully optimize TLSC designs to enhance commercialization efforts.
关键词： transparent luminescent solar concentrators,overlap integral,reabsorption loss,Stokes shift,near-infrared harvesting
更新于2025-09-23 15:21:01
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Rhenium and technetium-complexed silicon rhodamines as near-infrared imaging probes for bimodal SPECT- and optical imaging
摘要： Fluorescent Si-rhodamines were modified to enable complexation with the Re(I)- and 99mTc(I)-tricarbonyl core. The corresponding complexes exhibit suitable properties as bimodal imaging probes for SPECT- and optical imaging in vitro. Importantly, the novel in aqueous solution stable, functionalized Si-rhodamines retain favourable optical properties after complexation (QY=0.09, λabs=654 nm, λem=669 nm in PBS) and show promising near-infrared optical properties for potential in vivo applications enabling bimodal scintigraphic imaging and optical imaging, e.g. used in radio- and fluorescence-guided tumor resection.
关键词： SPECT,Optical imaging,Near-infrared imaging,Technetium,Rhenium,Silicon rhodamines
更新于2025-09-23 15:21:01
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Near-infrared nanosecond-pulsed laser-activated high efficient intracellular delivery mediated by nano-corrugated mushroom-shaped gold-coated polystyrene nanoparticles
摘要： Here, efficient intracellular delivery of molecules with high cell viability is reported using nanosecond-pulsed laser-activated plasmonic photoporation mediated by high-aspect-ratio nano-corrugated mushroom-shaped gold-coated polystyrene nanoparticles (nm-AuPNPs) at near-infrared wavelength. Upon laser illumination, nm-AuPNPs exhibit greater plasmonic extinction than spherical AuPNPs, which increase their energy efficiency and reduce the necessary illumination of light, effectively controlling cell damage and improving delivery efficiency. Nm-AuPNPs exhibit surface plasmon absorption at near infrared region with peak at 945 nm. Pulsed laser illumination at this plasmon peak triggers explosive nanobubbles, which create transient membrane pores, allowing the delivery of dyes, quantum dots and plasmids into the cells. The results can be tuned by laser fluence, exposure time, molecular size and concentration of nm-AuPNPs. The best results are found for CL1-0 cells, which yielded a 94% intracellular PI dye uptake and ~100% cell viability at 35 mJ/cm2 laser fluence for 945 nm wavelength. Thus, the presented approach has proven to have an inevitable potential for biological cell research and therapeutic applications.
关键词： near-infrared wavelength,intracellular delivery,nanosecond-pulsed laser,gold-coated polystyrene nanoparticles,plasmonic photoporation
更新于2025-09-23 15:21:01
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Vein detection with near-infrared organic photodetectors for biometric authentication
摘要： We combine a low dark current and high-detectivity near-infrared (NIR)-sensitive organic photodetector with a high-resolution 508 pixels per inch (ppi) oxide thin-film transistor (TFT) backplane to create a large-area thin NIR detector, using processes that are compatible with flat-panel display fabrication. The detector is characterized showing high uniformity and linearity. With the use of a NIR light source, the detector is capable of imaging the (pattern of) veins under the skin in reflection, leading to improved biometric authentication.
关键词： near-infrared organic photodiodes,vein detection,biometric authentication,large-area photodetector arrays
更新于2025-09-23 15:21:01
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Near-infrared fluorescence-guided surgery using indocyanine green facilitates secure infrapyloric lymph node dissection during laparoscopic distal gastrectomy
摘要： Purpose We aimed to investigate the usefulness of near-infrared indocyanine green (ICG)-enhanced fluorescence guidance for infrapyloric LN dissection in laparoscopic distal gastrectomy. Methods This study enrolled patients with early gastric cancer scheduled for laparoscopic distal gastrectomy. After intra-operative submucosal injection of ICG (0.1 mg/mL), LN dissection was conducted under near-infrared ICG fluorescence guidance. The operation time, bleeding events during infrapyloric LN dissection were analyzed. Cases were retrospectively 1:3 propensity-score matched to patients who underwent laparoscopic distal gastrectomy without ICG injection. Results The mean time from midline omentectomy to exposure of the right gastroepiploic vein was significantly shorter in the ICG group (n = 20) than in the non-ICG group (n = 60) (13.05 ± 5.77 vs 18.68 ± 7.92 min; p = 0.001), and the incidence of bleeding during infrapyloric LN dissection was lower in the ICG group (20% vs 68.3%, p < 0.001). The two groups did not differ significantly regarding the number of LNs retrieved from the infrapyloric area (p = 0.434). Conclusions Near-infrared ICG fluorescence guidance facilitates safe and fast infrapyloric LN dissection in laparoscopic distal gastrectomy.
关键词： Indocyanine green,Laparoscopic surgery,Lymph node dissection,Near-infrared imaging,Gastric cancer
更新于2025-09-23 15:21:01
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Staging laparoscopy with ultrasound and near-infrared fluorescence imaging to detect occult metastases of pancreatic and periampullary cancer
摘要： Introduction Up to 38% of pancreatic and periampullary cancer patients undergoing curative intended surgery turn out to have incurable disease. Therefore, staging laparoscopy (SL) prior to laparotomy is advised to spare patients the morbidity, inconvenience and expense of futile major surgery. The aim of this study was to assess the added value of SL with laparoscopic ultrasonography (LUS) and laparoscopic near-infrared fluorescence imaging (LFI). Methods All patients undergoing curative intended surgery of pancreatic or periampullary cancer were included prospectively in this single arm study. Patients received an intravenous infusion of 10 mg indocyanine green (ICG) one or two days prior to surgery to allow LFI. Suspect lesions were analyzed via biopsy or resection. Follow-up visits after surgery occurred every three months. Results A total of 25 patients were included. Suspect lesions were identified in 7 patients: liver metastases (n = 2; identified by inspection, LUS, and LFI), peritoneal metastases (n = 1; identified by inspection only), and benign lesions (n = 4; identified by inspection or LUS). Quality of LFI was good in 67% (10/15) of patients dosed one day and 89% (8/9) dosed two days prior to surgery. A futile laparotomy was averted in 3 patients (12%). Following SL the primary tumor was resected in 20 patients. Two patients (10%) developed metastases within 3 months after resection. Conclusions Despite current preoperative imaging modalities metastases are still identified during surgery. This study shows limited added value of LUS during SL in patients with pancreatic or periampullary cancer. LFI was of added value due to its high negative predictive value in case of suspect hepatic lesions identified by inspection.
关键词： near-infrared fluorescence imaging,staging laparoscopy,laparoscopic ultrasonography,pancreatic cancer,periampullary cancer,indocyanine green
更新于2025-09-23 15:21:01
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Identification of Hybrid Okra Seeds Based on Near-Infrared Hyperspectral Imaging Technology
摘要： Near-infrared (874–1734 nm) hyperspectral imaging technology combined with chemometrics was used to identify parental and hybrid okra seeds. A total of 1740 okra seeds of three different varieties, which contained the male parent xiaolusi, the female parent xianzhi, and the hybrid seed penzai, were collected, and all of the samples were randomly divided into the calibration set and the prediction set in a ratio of 2:1. Principal component analysis (PCA) was applied to explore the separability of different seeds based on the spectral characteristics of okra seeds. Fourteen and 86 characteristic wavelengths were extracted by using the successive projection algorithm (SPA) and competitive adaptive reweighted sampling (CARS), respectively. Another 14 characteristic wavelengths were extracted by using CARS combined with SPA. Partial least squares discriminant analysis (PLS-DA) and support vector machine (SVM) were developed based on the characteristic wavelength and full-band spectroscopy. The experimental results showed that the SVM discriminant model worked well and that the correct recognition rate was over 93.62% based on full-band spectroscopy. As for the discriminative model that was based on characteristic wavelength, the SVM model based on the CARS algorithm was better than the other two models. Combining the CARS+SVM calibration model and image processing technology, a pseudo-color map of sample prediction was generated, which could intuitively identify the species of okra seeds. The whole process provided a new idea for agricultural breeding in the rapid screening and identi?cation of hybrid okra seeds.
关键词： hybrid okra seeds,chemometrics,seed classification,near-infrared spectroscopy
更新于2025-09-23 15:21:01
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Local Overheating of Biotissue Labeled With Upconversion Nanoparticles Under Yb3+ Resonance Excitation
摘要： Local overheating of biotissue is a critical step for biomedical applications, such as photothermal therapy, enhancement of vascular permeability, remote control of drug release, and so on. Overheating of biological tissue when exposed to light is usually realized by utilizing the materials with a high-absorption cross section (gold, silica, carbon nanoparticles, etc.). Here, we demonstrate core/shell NaYF4:Yb3+, Tm3+/NaYF4 upconversion nanoparticles (UCNPs) commonly used for bioimaging as promising near-infrared (NIR) absorbers for local overheating of biotissue. We assume that achievable temperature of tissue labeled with nanoparticles is high enough because of Yb3+ resonance absorption of NIR radiation, whereas the use of auxiliary light-absorbing materials or shells is optional for photothermal therapy. For this purpose, a computational model of tissue heating based on the energy balance equations was developed and verified with the experimentally obtained thermal-graphic maps of a mouse in response to the 975-nm laser irradiation. Labeling of biotissue with UCNPs was found to increase the local temperature up to 2?C compared to that of the non-labeled area under the laser intensity lower than 1 W/cm2. The cellular response to the UCNP-initiated hyperthermia at subcritical ablation temperatures (lower than 42?C) was demonstrated by measuring the heat shock protein overexpression. This indicates that the absorption cross section of Yb3+ in UCNPs is relatively large, and microscopic temperature of nanoparticles exceeds the integral tissue temperature. In summary, a new approach based on the use of UCNP without any additional NIR absorbers was used to demonstrate a simple approach in the development of photoluminescent probes for simultaneous bioimaging and local hyperthermia.
关键词： near-infrared irradiation,local overheating,photothermal material,bioimaging,heat shock proteins,biotissue laser heating,hyperthermia,upconversion nanoparticles
更新于2025-09-23 15:21:01
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Drug Delivery System Using Photothermal Effect of Gold Nanorods
摘要： Gold nanorods have absorption bands in the near-infrared region. The absorbed light energy is converted into heat by gold nanorods. Therefore, drug delivery systems that can be controlled by the heat produced by near-infrared light irradiation will be constructed. First, we modified gold nanorods with double-stranded DNA. That is, release of single stranded DNA is induced by the produced heat from the gold nanorods. We also constructed a controlled release system of PEG chain mediated by retro Diels-Alder reaction induced by the photothermal effect. Next, we designed transdermal protein delivery system enhanced by the photothermal effect. We first casted gold nanorods, acting as a heating device in response to near-infrared light irradiation, onto the skin surface. After applying an aqueous solution of ovalbumin to the skin, the skin was irradiated by near-infrared laser light. The irradiation increased the skin temperature resulting in an efficient translocation of ovalbumin into the skin. Thus, the controlled-release systems and enhanced transdermal protein delivery system triggered by near-infrared light irradiation will be further expanded to development of functional drug delivery system.
关键词： photothermal effect,gold nanorods,transdermal protein delivery,drug delivery system,near-infrared light
更新于2025-09-23 15:21:01