Infrared Fluorescence Emission Research Articles

Intense 2.7 µm emission of Er3+/Pr3+ doped Ga5Ge20Sb10S65 chalcogenide glass

AbstractThere are numerous vital usages for mid‐infrared (MIR) lasers in satellite communication, biomedicine, military, remote sensing, and environmental monitoring. In this work, a progression of Er3+ ions doped, Er3+/Pr3+ ions co‐doped Ga5Ge20Sb10S65 glasses were prepared, and their physical performances and structural characteristics were examined. To understand the non‐phonon‐assisted energy transfer mechanism, we recorded the up‐conversion and infrared fluorescence emission spectra by pumping with a commercial 980 nm LD. Then the 2.7 µm strong fluorescence signal intensity can be obtained when the doped concentration of Pr3+ is proper. After the doping of Pr3+, fluorescence lifetime results revealed that the lifetimes of the Er3+:4I13/2 level fell dramatically from 7.33 to 1.90 ms, which experienced a much more significant decrease in lifetimes than the Er3+:4I11/2 level. The MIR fluorescence performances were assessed by the determined J–O parameters and relative emission cross sections. Additionally, the generally huge emission cross sections and the small pump energy show that it is possible to obtain population inversion with relatively small pump energy; thus the Er3+/Pr3+ glasses have great potential to be 2.7 µm laser materials.

Near-infrared fluorescent turn-on probe for hydrazine detection: environmental samples and live cell imaging.

An acetoxy naphthaldehyde conjugated benzophenoxazinium chloride chromophore-based-donor-π-acceptor (D-π-A) fluorescent probe BPN (benzophenoxazinium naphthoxy imine) displaying near-infrared (NIR) emission was reported for hydrazine detection. The chosen water-soluble benzophenoxazinium chloride chromophore has excellent photostability, a high molar extinction coefficient and fluorescence quantum yield (Φ = from 0.0075 to 0.6193), higher selectivity towards hydrazine and a longer fluorescence lifetime. In the presence of hydrazine, BPN exhibits near infrared fluorescence emission at 725 nm along with color change from light blue to red, as detected by the naked eye. Moreover, the BPN probe can selectively detect hydrazine (DL = 4.5 × 10-10 M) in a 90% aqueous DMSO solution without interfering with other analytes. As proof of real samples, the probe is successfully applied to sense hydrazine in thin layer chromatography (TLC) paper strips (both solution and vapor phases) and water and soil samples, suggesting its significant potential application. Also, due to its NIR emission and aqueous solubility, the BPN probe can be successfully used in live cell imaging with low cytotoxicity.

Double‐pronged Antimicrobial Agents based on a Donor‐π‐Acceptor Type Aggregation‐Induced Emission Luminogen

AbstractNovel antibacterial agents are urgently needed to control the infections induced by multidrug‐resistant (MDR) bacteria. Herein, we rationally designed and facilely synthesized a new D‐π‐A type luminogen with strong red/near‐infrared fluorescence emission, great aggregation‐induced emission (AIE) features, and excellent reactive oxygen species (ROS) production. The newly developed molecule TTTh killed the methicillin‐resistant Staphylococcus aureus (MRSA) by triggering the ROS accumulation in bacteria and interrupting the membrane integrity. Moreover, TTTh specifically targeted the lysosomes and potentiated their maturation to accelerate the clearance of intracellular bacteria. Additionally, reduced bacterial burden and improved healing were observed in TTTh‐treated wounds with negligible side effects. Our study expands the biological design and application of AIE luminogens (AIEgens), and provides new insights into discovering novel antibacterial targets and agents.

In Vivo Activity of Genetically Modified Cells Preseeded in Rat Vascularized Composite Allografts

Transplantation of the hand or face, known as vascularized composite allotransplantation (VCA), has revolutionized reconstructive surgery. Notwithstanding, there are still several areas of improvement to mitigate immune rejection while sparing systemic adverse effects. The goal of this study was to evaluate the engraftment and viability of a genetically modified cell population pre-engrafted into a VCA transplant, to potentially act as a local biosensor to report and modify the graft in vivo. A rat fibroblast cell line genetically modified to secrete Gaussia-Luciferase (gLuc), which served as a constitutive biomarker of cells, was incorporated into a VCA to study the viability of biosensor cells in a syngeneic rat heterotopic partial hindlimb transplantation model. Five perfusions were first performed as engineering runs to have a stable limb perfusion protocol, followed by 3 perfusions to analyze the cell engraftment during machine perfusion, and finally 4 perfusions to study in vivo persistence of the cell biosensors. Blood samples were collected to monitor gLuc secretion during perfusion and postoperatively. A time-dependent increase in gLuc secretion in the limb perfusion outflow during machine perfusion indirectly verified the presence of biosensors within the graft. After the ex vivo perfusion, VCA hindlimbs were analyzed for near infrared fluorescence emission that showed a presence of dyed engineered cells in all areas of the limbs. Postoperatively, gLuc was detectable 4 to 5 days after transplantation (W=16, P=.02857). This study demonstrated that engineered cells could be successfully preimplanted into VCAs-an important step toward development of an in vivo biosensor platform to use in modulating acute VCA outcomes.

Magnetic fluorescent molecularly imprinted nanoparticles for detection and separation of transferrin in human serum

Transferrin (TrF) is an important glycoprotein and disease biomarker that controls iron ion balance in the human body. Isolation and detection of TrF have important implication for the early detection of disease. Thus, a magnetic fluorescent molecularly imprinted nanoparticles (FMINPs) was prepared for extraction and fluorescence detection of TrF. The FMINPs was prepared with two steps, the first step was the synthesis of magnetic TrF imprinted nanoparticle and the second step was introducing a near-infrared fluorescent compound (CyA) on the imprinted nanoparticles, which has a strong near infrared fluorescence emission at 730 nm while excitation at 690 nm and a large fluorescence signal quenching after adsorption of TrF. The concentration of TrF can be determined by the change of the fluorescence signal. FT-IR, TEM and fluorescence spectrophotometer were used to verify the successful preparation and the fluorescence performance of the FMINPs. Under the optimized experimental conditions, the prepared FMINPs had a great fluorescence performance, offering the lower relative standard deviation (7.7%), good analytical range (0.025–0.175 mg/mL, R2 =0.998) and lower detection limit (0.0075 mg/mL) for TrF. This method provides a new solution for the direct detection and separation of TrF in human serum samples.

热离子交换型铝锗酸盐波导玻璃中钬离子的1.2 μm近红外荧光发射

热离子交换型铝锗酸盐波导玻璃中钬离子的1.2 μm近红外荧光发射

Novel mitochondria-targeted, nitrogen mustard-based DNA alkylation agents with near infrared fluorescence emission

In this report, the design of two novel nitrogen mustard-based DNA cross-linking agents with fluorophores incorporated into the structure (TN-A and TN-B) is disclosed. The results indicate that TN-A and TN-B can serve directly as both reporting and imaging agents for flow cytometry and gel electrophoresis without the necessity of another fluorescent tagging agents. TN-A and TN-B both selectively locate in the mitochondria and exhibit good antitumor activity. Notably, TN-A is the first DNA crosslinking agent with near infrared fluorescence emission properties.

A radiative transfer model to treat infrared molecular excitation in cometary atmospheres

The exospheres of small Solar System bodies are now observed with high spatial resolution from space missions. Interpreting infrared spectra of cometary gases obtained with the VIRTIS experiment onboard the Rosetta cometary mission requires detailed modeling of infrared fluorescence emission in optically thick conditions. Efficient computing methods are required since numerous ro-vibrational lines excited by the Sun need to be considered. We propose a new model working in a 3-D environment to compute numerically the local incoming radiation. It uses a new algorithm using pre-defined directions of ray propagation and ray grids to reduce the CPU cost in time with respect to Monte Carlo methods and to treat correctly the sunlight direction. The model is applied to the ν3 bands of CO2 and H2O at 4.3μm and 2.7μm respectively, and to the CO ∨(1→0) band at 4.7μm. The results are compared to the ones obtained by a 1-D algorithm which uses the Escape Probability (EP) method, and by a 3-D “Coupled Escape Probability” (CEP) model, for different levels of optical thickness. Our results suggest that the total band flux may vary strongly with azimuth for optically thick cases whereas the azimuth average total band flux computed is close to the one obtained with EP. Our model globally predicts less intensity reduction from opacity than the CEP model of Gersch and A’Hearn (Gersch, A.M., A’Hearn, M.F. [2014]. Astrophys. J. 787, 36–56). An application of the model to the observation of CO2, CO and H2O bands in 67/P atmosphere with VIRTIS is presented to predict the evolution of band optical thickness along the mission.

Infrared fluorescence from multiphoton dissociation of vinyl bromide: Emission from the products and the parent molecule

Abstract A time-resolved study of the infrared fluorescence emission produced in the infrared multiphoton dissociation of vinyl bromide at different experimental conditions has been carried out. Two different regimes, namely unimolecular and collisional, have been identified and characterized through the parent vinyl bromide and the HBr and C 2 H 2 photoproducts emissions. In the pressure interval studied, the formation of HBr has been determined to be mainly unimolecular, while the C 2 H 2 is produced through a collisionally assisted photodecomposition process. The collisional regime is explained in terms of the 3-centre elimination channel while the unimolecular regime is ascribed to the 4-centre mechanism. Relaxation rate constants for both the vibrationally excited HBr by vinyl bromide and by Ar and for vibrational excited VBr by unexcited VBr, are reported.

Optical characterization of Nd3+- and Er3+-doped lead-indium-phosphate glasses

In this work, Judd–Ofelt analysis is applied to rare-earth-doped lead-indium-phosphate glasses (RE-PbInPO4, where RE=Er3+ and Nd3+) in order to evaluate their potential as both glass laser systems and amplifier materials. The phenomenological Judd–Ofelt parameters Ω(2), Ω(4), and Ω(6) are determined for both rare-earth ions together with their quality factors and compared with the equivalent parameters for several other host glasses. The spontaneous emission probabilities and the lifetimes of the Nd3+ F43/2 laser transitions are determined and analyzed as a function of the optical quality factor. For Nd3+-PbInPO4, glass fluorescence emission (890, 1058, and 1330 nm) lines are observed. Highly efficient infrared-to-visible frequency up-conversion at 530, 550, and 670 nm as well as an intense infrared fluorescence emission (∼1540 nm) is observed in Er3+-doped PbIn(PO4) glasses pumped using 800 nm radiation excitation.

5422578 Magnetic resonance probehead

A time-resolved study of the infrared fluorescence emission produced in the infrared multiphoton dissociation of vinyl bromide at different experimental conditions has been carried out. Two different regimes, namely unimolecular and collisional, have been identified and characterized through the parent vinyl bromide and the HBr and C2H2 photoproducts emissions. In the pressure interval studied, the formation of HBr has been determined to be mainly unimolecular, while the C2H2 is produced through a collisionally assisted photodecomposition process. The collisional regime is explained in terms of the 3-centre elimination channel while the unimolecular regime is ascribed to the 4-centre mechanism. Relaxation rate constants for both the vibrationally excited HBr by vinyl bromide and by Ar and for vibrational excited VBr by unexcited VBr, are reported.

Slow intermolecular redistribution of vibrational energy in SF 6 gas excited by a tea CO 2 laser

Infra-red fluorescence (IRF) spectra of SF 6 excited by the 944.2 cm -1 line of a pulsed CO 2 laser were observed at various times after the time of the laser excitation. Each spectrum showed a strong IRF peak of the v 3 mode which was red shifted relative to the room temperature fundamental (948 cm -1) by an amount which depended, apart from the level of excitation, on the different times employed. For a strong excitation with 〈 n〉 ≈ 11 photons absorbed per molecule, a significant decrease of red shift versus time was observed, indicating mainly excitation losses by IRF emission. For weak excitation with 〈 n〉 ≈ 1.4, almost an constant red shift versus time is observed. This result, and the previous finding that at weak excitation a nonthermal energy distribution in the ensemble of molecules exists, leads to the conclusion that intermolecular redistribution of vibrational energy in SF 6 is slow, and does not exceed the observed fluorescence duration (∼1 ms).