- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Robust and Fragile Quantum Effects in the Transfer Kinetics of Delocalized Excitons between B850 Units of LH2 Complexes
摘要： Aggregates of light harvesting 2 (LH2) complexes form the major exciton-relaying domain in the photosynthetic unit of purple bacteria. Application of a generalized master equation to pairs of the B850 units of LH2 complexes, where excitons predominantly reside, provides quantitative information on how the inter-LH2 exciton transfer depends on the distance, relative rotational angle, and the relative energies of the two LH2s. The distance dependence demonstrates significant enhancement of the rate due to quantum delocalization of excitons, the qualitative nature of which remains robust against the disorder. The angle dependence reflects isotropic nature of exciton transfer, which remains similar for the ensemble of disorder. The variation of the rate on relative excitation energies of LH2 exhibits resonance peaks, which, however, is fragile as the disorder becomes significant. Overall, the average transfer times between two LH2s are estimated to be in the range of 4?25 ps for physically plausible inter-LH2 distances.
关键词： light harvesting 2 (LH2) complexes,quantum delocalization,exciton transfer,photosynthetic unit,purple bacteria,disorder
更新于2025-09-23 15:21:01
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Aluminum foil as a substrate for metal enhanced fluorescence of bacteria labelled with quantum dots, shows very large enhancement and high contrast
摘要： Very high surface/metal enhanced fluorescence was observed for E. coli single bacteria cells labeled with composite CdSeS/ZnS quantum dots (QDs) on three substrates: aluminum foil, aluminum film and gold film. The enhancement factors relative to maximum fluorescence intensity on glass for those substrates were in the range of several hundred (up to 500) for two-excitation wavelengths 532 and 633 nm. Contrast as a ratio of signals from QD labeled to signals of QD unlabeled (control) cells was also in the range of 100 s for those substrates and the highest contrast of 370 was observed on Al film. When CdTe QDs were used for labelling cells on all substrates or when fluorescence from cells with both QDs was measured on silver film, low or no enhancement was observed. Overall, untreated aluminum foil demonstrated great potential as low-cost substrate for surface/metal enhanced fluorescence, which delivers even more reproducible signal than gold film.
关键词： E. coli,Bacteria,Enhancement facor,Quantum dots,Single bacterial cell detection,Metal enhanced fluorescence,Contrast,Surface enhanced fluorescence,Aluminum foil,QD toxicity
更新于2025-09-23 15:21:01
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Blood–Retinal Barrier Compromise and Endogenous <i>Staphylococcus aureus</i> Endophthalmitis
摘要： PURPOSE. To test the hypothesis that blood–retinal barrier compromise is associated with the development of endogenous Staphylococcus aureus endophthalmitis. METHODS. To compromise the blood–retinal barrier in vivo, streptozotocin-induced diabetes was induced in C57BL/6J mice for 1, 3, or 5 months. Diabetic and age-matched nondiabetic mice were intravenously injected with 108 colony-forming units (cfu) of S. aureus, a common cause of endogenous endophthalmitis in diabetics. After 4 days post infection, electroretinography, histology, and bacterial counts were performed. Staphylococcus aureus–induced alterations in in vitro retinal pigment epithelial (RPE) cell barrier structure and function were assessed by anti–ZO-1 immunohistochemistry, FITC-dextran conjugate diffusion, and bacterial transmigration assays. RESULTS. We observed one bilateral infection in a control, nondiabetic animal (mean ? 1.54 3 103 6 1.78 3 102 cfu/eye, 7% incidence). Among the 1-month diabetic mice, we observed culture-con?rmed unilateral infections in two animals (mean ? 5.54 3 102 6 7.09 3 102 cfu/ eye, 12% incidence). Among the 3-month diabetic mice, infections were observed in 11 animals, three with bilateral infections (mean ? 2.67 3 102 6 2.49 3 102 cfu/eye, 58% incidence). Among the 5-month diabetic mice, we observed infections in ?ve animals (mean ? 7.88 3 102 6 1.08 3 103 cfu/eye, 33% incidence). In vitro, S. aureus infection reduced ZO-1 immunostaining and disrupted the barrier function of cultured RPE cells, resulting in diffusion of ?uorophore-conjugated dextrans and transmigration of live bacteria across a permeabilized RPE barrier. CONCLUSIONS. Taken together, these results indicated that S. aureus is capable of inducing blood–retinal barrier permeability and causing endogenous bacterial endophthalmitis in normal and diabetic animals.
关键词： Staphylococcus aureus,endogenous endophthalmitis,blood–retinal barrier,bacteria,diabetes,retinal pigment epithelium
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Nanoprobe-Enabled Electron Beam Induced Current Measurements on III-V Nanowire-Based Solar Cells
摘要： The development of two new types of high-density, electroless plated microelectrode arrays for CMOS-based high-sensitivity direct bacteria and HeLa cell counting are presented. For emerging high-sensitivity direct pathogen counting, two technical challenges must be addressed. One is the formation of a bacteria-sized microelectrode, and the other is the development of a high-sensitivity and high-speed amperometry circuit. The requirement for microelectrode formation is that the gold microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the dimensions of the microelectrodes on a CMOS sensor chip in this work were successfully reduced to 1.2 μm × 2.05 μm. This is 1/20th of the smallest size reported in the literature. Since a bacteria-sized microelectrode has a severe limitation on the current flow, the amperometry circuit has to have a high sensitivity and high speed with low noise. In this work, a current buffer was inserted to mitigate the potential fluctuation. Three test chips were fabricated using a 0.6-μm CMOS process: two with 1.2 μm × 2.05 μm 1024 × 1024 and 4 μm × 4 μm (16 × 16) sensor arrays and one with 6-μm × 6-μm (16 × 16) sensor arrays; and the microelectrodes were formed on them using electroless plating. The uniformity among the 1024 × 1024 electrodes arranged with a pitch of 3.6 μm × 4.45 μm was optically verified. For improving sensitivity, the trenches on each microelectrode were developed and verified optically and electrochemically for the first time. Higher sensitivity can be achieved by introducing a trench structure than by using a conventional microelectrode formed by contact photolithography. Cyclic voltammetry (CV) measurements obtained using the 1.2 μm × 2.05 μm 16 × 16 and 6-μm × 6-μm 16 × 16 sensor arrays with electroless-plated microelectrodes successfully demonstrated direct counting of the bacteria-sized microbeads and HeLa cells.
关键词： Bacteria counting,HeLa cells,electroless plating,point-of-care testing,CMOS,microelectrode array
更新于2025-09-23 15:19:57
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Plasmonic nanoparticles assemblies templated by helical bacteria and resulting optical activity
摘要： Plasmonic nanoparticles (NPs) adsorbing onto helical bacteria can lead to formation of NP helicoids with micron scale pitch. Associated chiroptical effects can be utilized as bioanalytical tool for bacterial detection and better understanding of the spectral behavior of helical self-assembled structures with different scales. Here, we report that enantiomerically pure helices with micron scale of chirality can be assembled on Campylobacter jejuni, a helical bacterium known for severe stomach infections. These organisms have right-handed helical shapes with a pitch of 1–2 microns and can serve as versatile templates for a variety of NPs. The bacteria itself shows no observable rotatory activity in the visible, red, and near-IR ranges of electromagnetic spectrum. The bacterial dispersion acquires chiroptical activity at 500–750 nm upon plasmonic functionalization with Au NPs. Finite-difference time-domain simulations confirmed the attribution of the chiroptical activity to the helical assembly of gold nanoparticles. The position of the circular dichroism peaks observed for these chiral structures overlaps with those obtained before for Au NPs and their constructs with molecular and nanoscale chirality. This work provides an experimental and computational pathway to utilize chiroplasmonic particles assembled on bacteria for bioanalytical purposes.
关键词： bacteria,simulation,C. jejuni,circular dichroism,plasmonic,mesoscale,gold nanoparticle,biotechnology
更新于2025-09-23 15:19:57
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Handbook of Smart Photocatalytic Materials || Sustainable photocatalytic porcelain gr??s slabs active under LED light for indoor depollution and bacteria reduction
摘要： The photocatalytic performances of TiO2-based and doped Ag-TiO2-based porcelain grés ceramic tiles as self-cleaning materials developed by digital printing process were investigated. The photoactive tiles coated with doped Ag-TiO2 K1077 showed better photocatalytic efficiency than tiles coated with TiO2 K1077 for the degradation of NOx and ethanol due to the better light absorption and higher electron–hole pairs separation caused by Ag nanoparticles. The total mineralization of EtOH to CO2 was proved. The photoactive tiles also exhibited an excellent efficiency for the densification of E. coli and S. aureus. These experimental data manifested the efficient and durable water and air treatment/densification using Ag-TiO2-based porcelain grés ceramic tiles, which may be significant to future use as self-cleaning materials.
关键词： LED light,bacteria reduction,porcelain grés ceramic tiles,photocatalytic,depollution,Ag-TiO2,TiO2,self-cleaning
更新于2025-09-23 15:19:57
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Rapid label-free detection of intact pathogenic bacteria <i>in situ via</i> surface plasmon resonance imaging enabled by crossed surface relief gratings
摘要： The unique plasmonic energy exchange occurring within metallic crossed surface relief gratings (CSRGs) has recently motivated their use as biosensors. However, CSRG-based biosensing has been limited to spectroscopic techniques, failing to harness their potential for integration with ubiquitous portable electronics. Here, we introduce biosensing via surface plasmon resonance imaging (SPRi) enabled by CSRGs. The SPRi platform is fully integrated including optics and electronics, has bulk sensitivity of 613 Pixel Intensity Unit (PIU)/Refractive Index Unit (RIU), a resolution of 10?6 RIU and a signal-to-noise ratio of ～33 dB. Finite-Difference Time-Domain (FDTD) simulations confirm that CSRG-enabled SPRi is supported by an electric field intensity enhancement of ～30 times, due to plasmon resonance at the metal-dielectric interface. In the context of real-world biosensing applications, we demonstrate the rapid (<35 min) and label-free detection of uropathogenic E. coli (UPEC) in PBS and human urine samples for concentrations ranging from 103 to 109 CFU mL?1. The detection limit of the platform is ～100 CFU mL?1, three orders of magnitude lower than the clinical detection limit for diagnosis of urinary tract infection. This work presents a new avenue for CSRGs as SPRi-based biosensing platforms and their great potential for integration with portable electronics for applications requiring in situ detection.
关键词： crossed surface relief gratings,portable electronics,biosensing,pathogenic bacteria detection,surface plasmon resonance imaging
更新于2025-09-23 15:19:57
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A Nanostructured Gold/Graphene Microfluidic Device for Direct and Plasmonic-Assisted Impedimetric Detection of Bacteria
摘要： Hierarchical 3D gold nano-micro islands (NMIs) are favourably structured for direct and probe-free capture of bacteria in optical and electrochemical sensors. Moreover, their unique plasmonic properties make them a suitable candidate for plasmonic-assisted electrochemical sensors, yet the charge transfer needs to be improved. In the present study, we propose a novel plasmonic-assisted electrochemical impedimetric detection platform based on hybrid structures of 3D gold NMIs and graphene (Gr) nanosheets for probe-free capture and label-free detection of bacteria. The inclusion of Gr nanosheets significantly improves the charge transfer, addressing the central issue of using 3D gold NMIs. Notably, the 3D gold NMIs/Gr detection platform successfully distinguishes between various types of bacteria including Escherichia coli (E. coli) K12, Pseudomonas putida (P. putida) and Staphylococcus epidermidis (S. epidermidis) when electrochemical impedance spectroscopy is applied under visible light. We show that distinguishable and label-free impedimetric detection is due to dissimilar electron charge transfer caused by various sizes, morphologies, and compositions of the cells. In addition, the finite-difference time-domain (FDTD) simulation of the electric field indicates the intensity of charge distribution at the edge of the NMI structures. Furthermore, the wettability studies demonstrated that contact angle is a characteristic feature of each type of captured bacteria on the 3D gold NMIs, which strongly depends on the shape, morphology, and size of the cells. Ultimately, exposing the platform to various dilutions of the three bacteria strains, revealed the ability to detect dilutions as low as ~20 CFU/mL in a wide linear range of detection of 2(cid:3)101-105, 2(cid:3)101-104 and 1(cid:3)102-1(cid:3)105 CFU/mL for E. coli, P. putida, and S. epidermidis, respectively. The proposed hybrid structure of 3D gold NMIs and Gr combined by novel plasmonic and conventional impedance spectroscopy techniques open interesting avenues in ultrasensitive label-free detection of bacteria with low cost and high stability.
关键词： Label-free bacteria detection,Hierarchical gold nano-micro islands,Surface properties,Impedance spectroscopy,plasmonic-assisted electrochemical detection platform
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 4th Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - Chengdu, China (2019.12.20-2019.12.22)] 2019 IEEE 4th Advanced Information Technology, Electronic and Automation Control Conference (IAEAC) - Deterministic hierarchical joint remote state preparation using partially entangled quantum channel
摘要： The development of two new types of high-density, electroless plated microelectrode arrays for CMOS-based high-sensitivity direct bacteria and HeLa cell counting are presented. For emerging high-sensitivity direct pathogen counting, two technical challenges must be addressed. One is the formation of a bacteria-sized microelectrode, and the other is the development of a high-sensitivity and high-speed amperometry circuit. The requirement for microelectrode formation is that the gold microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the dimensions of the microelectrodes on a CMOS sensor chip in this work were successfully reduced to 1.2 μm × 2.05 μm. This is 1/20th of the smallest size reported in the literature. Since a bacteria-sized microelectrode has a severe limitation on the current flow, the amperometry circuit has to have a high sensitivity and high speed with low noise. In this work, a current buffer was inserted to mitigate the potential fluctuation. Three test chips were fabricated using a 0.6-μm CMOS process: two with 1.2 μm × 2.05 μm 1024 × 1024 and 4 μm × 4 μm (16 × 4) sensor arrays and one with 6-μm × 6-μm (16 × 16) sensor arrays; and the microelectrodes were formed on them using electroless plating. The uniformity among the 1024 × 1024 electrodes arranged with a pitch of 3.6 μm × 4.45 μm was optically verified. For improving sensitivity, the trenches on each microelectrode were developed and verified optically and electrochemically for the first time. Higher sensitivity can be achieved by introducing a trench structure than by using a conventional microelectrode formed by contact photolithography. Cyclic voltammetry (CV) measurements obtained using the 1.2 μm × 2.05 μm 16 × 4 and 6-μm × 6-μm 16 × 16 sensor arrays with electroless-plated microelectrodes successfully demonstrated direct counting of the bacteria-sized microbeads and HeLa cells.
关键词： microelectrode array,point-of-care testing,HeLa cells,electroless plating,Bacteria counting,CMOS
更新于2025-09-23 15:19:57
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A multifunctional platform with single-NIR-laser-triggered photothermal and NO release for synergistic therapy against multidrug-resistant Gram-negative bacteria and their biofilms
摘要： Background: Infectious diseases caused by multidrug-resistant (MDR) bacteria, especially MDR Gram-negative strains, have become a global public health challenge. Multifunctional nanomaterials for controlling MDR bacterial infections via eradication of planktonic bacteria and their biofilms are of great interest. Results: In this study, we developed a multifunctional platform (TG-NO-B) with single NIR laser-triggered PTT and NO release for synergistic therapy against MDR Gram-negative bacteria and their biofilms. When located at the infected sites, TG-NO-B was able to selectively bind to the surfaces of Gram-negative bacterial cells and their biofilm matrix through covalent coupling between the BA groups of TG-NO-B and the bacterial LPS units, which could greatly improve the antibacterial efficiency, and reduce side damages to ambient normal tissues. Upon single NIR laser irradiation, TG-NO-B could generate hyperthermia and simultaneously release NO, which would synergistically disrupt bacterial cell membrane, further cause leakage and damage of intracellular components, and finally induce bacteria death. On one hand, the combination of NO and PTT could largely improve the antibacterial efficiency. On the other hand, the bacterial cell membrane damage could improve the permeability and sensitivity to heat, decrease the photothermal temperature and avoid damages caused by high temperature. Moreover, TG-NO-B could be effectively utilized for synergistic therapy against the in vivo infections of MDR Gram-negative bacteria and their biofilms and accelerate wound healing as well as exhibit excellent biocompatibility both in vitro and in vivo. Conclusions: Our study demonstrates that TG-NO-B can be considered as a promising alternative for treating infections caused by MDR Gram-negative bacteria and their biofilms.
关键词： Biofilms,Single-NIR-laser-triggered,Graphene,NO release,Multidrug-resistant Gram-negative bacteria,Synergistic,Photothermal
更新于2025-09-23 15:19:57