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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

A matter of collection and detection for intraoperative and noninvasive near-infrared fluorescence molecular imaging: To see or not to see?

Purpose: Although fluorescence molecular imaging is rapidly evolving as a new combinational drug/device technology platform for molecularly guided surgery and noninvasive imaging, there remains no performance standards for efficient translation of “first-in-humans” fluorescent imaging agents using these devices. Methods: The authors employed a stable, solid phantom designed to exaggerate the confounding effects of tissue light scattering and to mimic low concentrations (nM–pM) of near-infrared fluorescent dyes expected clinically for molecular imaging in order to evaluate and compare the commonly used charge coupled device (CCD) camera systems employed in preclinical studies and in human investigational studies. Results: The results show that intensified CCD systems offer greater contrast with larger signal-to-noise ratios in comparison to their unintensified CCD systems operated at clinically reasonable, subsecond acquisition times. Conclusions: Camera imaging performance could impact the success of future “first-in-humans” near-infrared fluorescence imaging agent studies.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

TU-A-9A-05: First Experimental Demonstration of the Anisotropic Detection Principle in X-Ray Fluorescence Computed Tomography

Purpose: To improve the sensitivity of X-ray fluorescence computed tomography (XFCT) for in vivo molecular imaging. Is the maximum sensitivity achieved with an isotropic (4π) detector configuration? We prove that this is not necessarily true, and that a greater sensitivity is possible with anisotropic detector configuration. Methods: An XFCT imaging system was constructed consisting of 1) a collimated pencil beam x-ray source using a fluoroscopy grade x-ray tube; 2) a CdTe x-ray photon counting detector to detect fluorescent x-rays; and 3) a rotation/translation stage for tomographic imaging. We created a 6.5-cm diameter water phantom with 2-cm inserts of low gold concentration (0.25%–1%) to simulate tumors targeted by gold nano-particles. The placement of x-ray fluorescence detector were chosen to minimize scatter x-rays. XFCT imaging was performed at three different detector positions (60°, 90°, 145°) to determine the impact of forward-scatter, side-scatter, and back-scatter on imaging performance. The three data sets were also combined to estimate the imaging performance with an isotropic detector. Results: The highest imaging performance was achieved when the XF detector was in the backscatter 145° configuration. The signal-to-noise ratio (SNR) was 5.5 for the 0.25% gold concentration compared to SNRs of 1.4, 0, and 2.4 for 60°, 90°, and combined (60°+90°+145°) datasets. Only the 145° detector arrangement alone could detect the 0.25% concentration. The imaging dose was 14 mGy for each detector arrangement experiment. Conclusion: This study experimentally proves, for the fist time, the Anisotropic Detection Principle in XF imaging, which holds that optimized anisotropic x-ray fluorescence detection provides greater sensitivity than isotropic detection. The optimized detection arrangement was used to improve the sensitivity of the XFCT experiment. The achieved XFCT sensitivity is the highest ever for a phantom at least this large using a benchtop x-ray source, which is an important step toward clinical XFCT molecular imaging. This work was supported by the NCI fellowship grant R25T-CA118681 and by the NIH (1R01-EB016777) and NIBIB (1K99-EB016059)

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Erratum to: “The Fluorescence and Electronic Structure of Phenyl-Substituted Tetraazachlorin Molecules” [Optics and Spectroscopy 117, 722 (2014)]

should read “porphyrazine” instead of “porphyrazin”;should read “intersystem crossing” instead of “intercombinational conversion”;should read “mirror-symmetrical” instead of “reflection-symmetric”;should read “fluorescence enhancement” instead of “fluorescence buildup.”Page 722, Abstract, lines 9–10 from the top, the sentence should read:This characteristic increases upon tetrapyrrole phenylation.Page 727, left column, lines 17–18 from the top, the sentence should read:The vibronic transition parts of the emission spectrum are diffuse, (…)Page 727, left column, lines 29–30 from the top, the sentence should read:Note that the Stokes shift in these cases is relatively large.Page 729, left column, lines 8–10 from the bottom, the sentence should read:For H{sub 2}Ph{sub 8}TAC{sup mp} and H{sub 2}Ph{sub 6}TAC{sup tm}, the enhancement of fluorescence is weaker than in the former case: on cooling, τ{sub F} is increased by a factor of 4–5 in MTHF and by a factor of only 2.6–3 in toluene.Page 729, right column, lines 9–10 from the footnote, the sentence should read:It is seen from Table 1 that our results agree reasonably well with previously reported data.Page 730, left column, lines 16–19 from the top, the sentence should read:The lifetime for the outgassed H{sub 2}TAP solution intoluene (τ{sub T}{sup 0}) was measured by A.S. Stasheuski as phosphorescence decay at λ{sub reg} = 1070 nm using the setup described in [29].Page 730, left column, lines 20–23 from the top, the sentence should read:The τ{sub T} value derived from the kinetics of the rise of singlet oxygen luminescence [26] for the nonoutgassed solution at λ{sub reg} = 1272 nm is 162 ns;Page 730, right column, lines 25–27 from the top, the sentence should read:Therefore, for H{sub 2}TAP (λ{sub F}{sup 00}≈ 620 nm), the internal conversion probability should not be high.Page 731, left column, the heading of Table 2 should read:Bond lengths in the porphine macrocycle (Å).Page 731, left column, lines 3–6 from the top, the sentence should read:For elucidating the mechanism of the deactivation of the S{sub 1} state, it was of essential interest to see whether the enhancement of H{sub 2}TAP fluorescence would be observed at 77 K.Page 733, left column, lines 2–3 from the top, the sentence should read:The corresponding difference for the H{sub 2}P–H{sub 2}C pair is 0.013 Å.Page 733, left column, lines 14–16 from the top, the sentence should read:The macrocycle undergoes additional contraction, and the symmetry of its conjugated system is very close to D{sub 2h}.Page 733, right column, line 21 from the top should read:Replacement of the methine bridges (…)Page 734, left column, lines 8–11 from the figure caption, the sentence should read:This is the main reason of the large bathochromic shift of the Soret band of H{sub 2}Ph{sub 8}TAP and MgPh{sub 8}TAP [16] relative to H{sub 2}TAP and MgTAP, respectively.Page 734, left column, lines 1–4 from the bottom, the sentence should read:The complete INDO/Sm calculation yields the corresponding quantitative characteristics, which are in good agreement with experimental data (see below).Page 740, left column, reference no. 25 should read:25. V. A. Galievsky, A. S. Stasheuski, V. V. Kiselyov, A. I. Shabusov, M. V. Belkov, and B. M. Dzhagarov, Instrum. Exp. Tech. 53, 568 (2010).25. V. A. Galievsky, A. S. Stasheuski, V. V. Kiselyov, A. I. Shabusov, M. V. Belkov, and B. M. Dzhagarov, Instrum. Exp. Tech. 53, 568 (2010).30. V. L. Ermolaev and E. B. Sveshnikova, Acta Phys. Pol. 34, 771 (1968).

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2015

Quantitative time-averaged gas and liquid distributions using x-ray fluorescence and radiography in atomizing sprays

A method for quantitative measurements of gas and liquid distributions is demonstrated using simultaneous x-ray fluorescence and radiography of both phases in an atomizing coaxial spray. Synchrotron radiation at 10.1 keV from the Advanced Photon Source at Argonne National Laboratory is used for x-ray fluorescence of argon gas and two tracer elements seeded into the liquid stream. Simultaneous time-resolved x-ray radiography combined with time-averaged dual-tracer fluorescence measurements enabled corrections for reabsorption of x-ray fluorescence photons for accurate, line-of-sight averaged measurements of the distribution of the gas and liquid phases originating from the atomizing nozzle.

absorption↗
DOE OSTI2011

Fluorescent Labeling of Antibody Fragments Using Split GFP

Antibody fragments are easily isolated from in vitro selection systems, such as phage and yeast display. Lacking the Fc portion of the antibody, they are usually labeled using small peptide tags recognized by antibodies. In this paper we present an efficient method to fluorescently label single chain Fvs (scFvs) using the split green fluorescent protein (GFP) system. A 13 amino acid tag, derived from the last beta strand of GFP (termed GFP11), is fused to the C terminus of the scFv. This tag has been engineered to be non-perturbing, and we were able to show that it exerted no effect on scFv expression or functionality when compared to a scFv without the GFP11 tag. Effective functional fluorescent labeling is demonstrated in a number of different assays, including fluorescence linked immunosorbant assays, flow cytometry and yeast display. Furthermore, we were able to show that this split GFP system can be used to determine the concentration of scFv in crude samples, as well an estimate of antibody affinity, without the need for antibody purification. We anticipate this system will be of widespread interest in antibody engineering and in vitro display systems.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Construction, characterization and crystal structure of a fluorescent single-chain Fv chimera [Slides]

Conclusions of the presentation were: The scTGPs are recombinant intrinsically fluorescent antibodies, ready for use in traditional fluorescent antibody based assays; The scFPs can be constructed as vL-FP-vH format, TGP an extremely stable monomeric fluorescent protein is suitable FP; The scFPs can be effectively displayed on yeast, where they function similarly to their corresponding scFv counterparts, recognize specific antigen similar affinity; Functional expression levels of scFPs in the bacterial cytoplasm are relatively high and can rescue some scFvs otherwise expressed at low levels in the periplasm; Straightforward assessment of expression levels and monitoring of protein purification steps; Antigen recognition in one step binding assays, novel assays such as epitope binning TGP is a monomeric fluorescent protein amenable to crystallization. These features provide unique and valuable characteristics to scTGP molecules for their use in protein chemistry; and, We present unique antibody format with wide variety of use in research and clinical setting

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Chlorophyll fluorescence is a potential indicator to measure photochemical efficiency in early to late soybean maturity groups under changing day lengths and temperatures

In this study, we employed chlorophyll a fluorescence technique, to indicate plant health and status in response to changing day lengths (photoperiods) and temperatures in soybean early and late maturity groups. Chlorophyll a fluorescence study indicates changes in light reactions in photosystem II. Experiments were performed for 3-day lengths (12.5, 13.5, and 14.5 h) and five temperatures (22/14°C, 26/18°C, 30/22°C, 34/26°C, and 40/32°C), respectively. The I-P phase declined for changing day lengths. Active reaction centers decreased at long day length for maturity group III. We observed that low temperatures impacted the acceptor side of photosystem II and partially impacted electron transport toward the photosystem I end electron acceptor. Results emphasized that higher temperatures (40/32°C) triggered damage at the oxygen-evolving complex and decreased electron transport and photosynthesis. We studied specific leaf areas and aboveground mass. Aboveground parameters were consistent with the fluorescence study. Chlorophyll a fluorescence can be used as a potential technique for high-throughput phenotyping methods. The traits selected in the study proved to be possible indicators to provide information on the health status of various maturity groups under changing temperatures and day lengths. These traits can also be deciding criteria for breeding programs to develop inbreed soybean lines for stress tolerance and sensitivity based on latitudinal variations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

ON THE CONTRIBUTION OF FLUORESCENCE TO LYα HALOS AROUND STAR-FORMING GALAXIES

We quantify the contribution of Lyα fluorescence to observed spatially extended Lyα halos around Lyα emitters at redshift z = 3.1. The key physical quantities that describe the fluorescent signal include (i) the distribution of cold gas in the circumgalactic medium (CGM); we explore simple analytic models and fitting functions to recent hydrodynamical simulations; and (ii) local variations in the ionizing background due to ionizing sources that cluster around the central galaxy. We account for clustering by boosting the observationally inferred volumetric production rate of ionizing photons, ϵ{sub LyC}, by a factor of 1+ξ{sub LyC}(r), in which ξ{sub LyC}(r) quantifies the clustering of ionizing sources around the central galaxy. We compute ξ{sub LyC}(r) by assigning an “effective” bias parameter to the ionizing sources. This novel approach allows us to quantify our ignorance of the population of ionizing sources in a simple parametrized form. We find a maximum enhancement in the local ionizing background in the range 50–200 at r ∼ 10 physical kpc. For spatially uncorrelated ionizing sources and fluorescing clouds we find that fluorescence can contribute up to ∼ 50%–60% of the observed spatially extended Lyα emission. We briefly discuss how future observations can shed light on the nature of Lyα halos around star-forming galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

A solar-pumped fluorescence model for line-by-line emission intensities in the B–X, A–X, AND X–X band systems of {sup 12}C{sup 14}N

We present a new quantitative model for detailed solar-pumped fluorescent emission of the main isotopologue of CN. The derived fluorescence efficiencies permit estimation and interpretation of ro-vibrational infrared line intensities of CN in exospheres exposed to solar (or stellar) radiation. Our g-factors are applicable to astronomical observations of CN extending from infrared to optical wavelengths, and we compare them with previous calculations in the literature. The new model enables extraction of rotational temperature, column abundance, and production rate from astronomical observations of CN in the inner coma of comets. Our model accounts for excitation and de-excitation of rotational levels in the ground vibrational state by collisions, solar excitation to the A{sup 2}Π{sub i} and B{sup 2}Σ{sup +} electronically excited states followed by cascade to ro-vibrational levels of X{sup 2}Σ{sup +}, and direct solar infrared pumping of ro-vibrational levels in the X{sup 2}Σ{sup +} state. The model uses advanced solar spectra acquired at high spectral resolution at the relevant infrared and optical wavelengths and considers the heliocentric radial velocity of the comet (the Swings effect) when assessing the exciting solar flux for a given transition. We present model predictions for the variation of fluorescence rates with rotational temperature and heliocentric radial velocity. Furthermore, we test our fluorescence model by comparing predicted and measured line-by-line intensities for X{sup 2}Σ{sup +} (1–0) in comet C/2014 Q2 (Lovejoy), thereby identifying multiple emission lines observed at IR wavelengths.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Fluorescent bioaerosol particle concentrations measured by the DU WIBS during the AGINSGP field experiment

Real-time, immersion mode ambient fluorescent bioaerosol concentrations were measured at ARM’s Southern Great Plains (SGP) site during the AGINSGP field experiment using a Wideband Integrated Bioaerosol Sensor (DMT Inc.; WIBS-4A). The WIBS-4A is an optical particle counter that also measures single particle fluorescence in three channels, along with particle asymmetry. Particles are grouped into different types depending on which channels they fluoresce in. The instrument was located in the guest instrument facility (GIF) and measured fluorescent particle concentrations from April 7th to April 29th. Data presented here are the concentrations for each particle type, binned in 5 minute increments. Air was drawn into the GIF through custom aluminum stack inlets (6” inner diameter) attached vertically to the outer GIF wall and the GIF outside platform. A blower pulled air through the stacks at a velocity of 1 m/s. Aerosol instruments subsampled via wall ports, through either 3/8” or 1/4" copper lines, depending on sample flow of the instrument. Particles were dried using a silica diffusion dryer prior to analysis.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRSDate not supplied

A Comparison of NO Laser-Induced Fluorescence Models at Conditions Relevant to Supersonic and Hypersonic Flows

Planar laser-induced fluorescence (PLIF) of the nitric oxide (NO) molecule has been widely used in wind tunnel facilities for flow visualization, velocity, and temperature measurements. The experimental PLIF measurements are often compared with synthetic PLIF images using computationally derived temperatures, pressures, velocities, and species mole fractions. This approach is commonly referred to as computational flow imaging (CFI). In the present work, we compare signal intensity from PLIF models with experimental PLIF measurements obtained within a low pressure gas cell system at pressures and NO mole fractions relevant to supersonic and hypersonic flowfields. Experimental measurements were compared to several different laser induced-fluorescence models reported in the literature including LIFBASE, LINUS, and a NASA two-level model. The experimental measurements agreed well with all of the models at lower pressures and lower NO mole fractions; the fluorescence there is linear with both of these parameters. However, at higher pressures and mole fractions, the signal becomes nonlinear with respect to these parameters as self-quenching limits the signal and absorption further limits the signal. In fact, for the experimental path length of the experiment, the combination of high pressure and high NO mole fraction causes the experimental results to deviate significantly from the predicted results that neglect absorption of the incident laser sheet. The LINUS model, which allows absorption to be calculated, provided results that agreed better with the experimental measurements. Since supersonic and hypersonic flowfields may contain a region of the flow with high pressures and measurements in large-scale facilities often include a long path length, neglecting absorption may have a significantly negative effect on the CFI comparison to experimental PLIF images. As a result, PLIF models that account for absorption should be included in computational flow imaging approaches for laser induced fluorescence.

laser-induced fluorescence↗
NASA NTRSDate not supplied

Towards Simultaneous Multi-Parameter Measurements Using Burst-Mode Frequency-Scanning Planar Laser-Induced Fluorescence

While planar laser-induced fluorescence (PLIF) can provide valuable flow visualization, there are many challenges in extracting quantitative measurements from the fluorescence intensity. To overcome the multi-parameter dependence of the signal intensity, frequency scanning planar laser-induced fluorescence (FS-PLIF) provides the potential for 2D temperature, pressure, and velocity measurements by spectrally resolving the excitation spectrum of one or more fluorescence transitions to extract the Doppler shift, Doppler- and collisional-broadening of absorption lines, and the relative signal intensities of multiple transitions. This work aims to characterize a burst-mode FS-PLIF system consisting of a Spectral Energies, LLC burst-mode laser coupled with a Spectral Energies, LLC optical parametric oscillator using nitric oxide (NO) static pressure cell measurements. The effect of the OPO cavity on intensity fluctuations during frequency-scanning is investigated. A NO PLIF model is implemented to investigate the feasibility of property measurements using single- and two-NO-line scans.

burst-mode laser↗
DOE OSTI2013

Phanta: A Non-Fluorescent Photochromic Acceptor for pcFRET

We have developed an orange non-fluorescent photochromic protein (quantum yield, 0.003) we call Phanta that is useful as an acceptor in pcFRET applications. Phanta can be repeatedly inter-converted between the two absorbing states by alternate exposure to cyan and violet light. The absorption spectra of Phanta in one absorbing state shows excellent overlap with the emission spectra of a number of donor green fluorescent proteins including the commonly used EGFP. We show that the Phanta-EGFP FRET pair is suitable for monitoring the activation of caspase 3 in live cells using readily available instrumentation and a simple protocol that requires the acquisition of two donor emission images corresponding to Phanta in each of its photoswitched states. This the first report of a genetically encoded non-fluorescent acceptor for pcFRET.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2014

Portable total reflection x-ray fluorescence analysis in the identification of unknown laboratory hazards

In this study, a portable total reflection x-ray fluorescence (TXRF) spectrometer was used to analyze unknown laboratory hazards that precipitated on exterior surfaces of cooling pipes and fume hood pipes in chemical laboratories. With the aim to examine the accuracy of TXRF analysis for the determination of elemental composition, analytical results were compared with those of wavelength-dispersive x-ray fluorescence spectrometry, scanning electron microscope and energy-dispersive x-ray spectrometry, energy-dispersive x-ray fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, x-ray diffraction spectrometry (XRD), and x-ray photoelectron spectroscopy (XPS). Detailed comparison of data confirmed that the TXRF method itself was not sufficient to determine all the elements (Z > 11) contained in the samples. In addition, results suggest that XRD should be combined with XPS in order to accurately determine compound composition. This study demonstrates that at least two analytical methods should be used in order to analyze the composition of unknown real samples.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

A method of measuring gold nanoparticle concentrations by x-ray fluorescence for biomedical applications

Purpose: This paper reports a technique that enables the quantitative determination of the concentration of gold nanoparticles (GNPs) through the accurate detection of their fluorescence radiation in the diagnostic x-ray spectrum. Methods: Experimentally, x-ray fluorescence spectra of 1.9 and 15 nm GNP solutions are measured using an x-ray spectrometer, individually and within chicken breast tissue samples. An optimal combination of excitation and emission filters is determined to segregate the fluorescence spectra at 66.99 and 68.80 keV from the background scattering. A roadmap method is developed that subtracts the scattered radiation (acquired before the insertion of GNP solutions) from the signal radiation acquired after the GNP solutions are inserted. Results: The methods effectively minimize the background scattering in the spectrum measurements, showing linear relationships between GNP solutions from 0.1% to 10% weight concentration and from 0.1% to 1.0% weight concentration inside a chicken breast tissue sample. Conclusions: The investigation demonstrated the potential of imaging gold nanoparticles quantitatively in vivo for in-tissue studies, but future studies will be needed to investigate the ability to apply this method to clinical applications.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Stepwise Assembly of Turn‐on Fluorescence Sensors in Multicomponent Metal–Organic Frameworks for in Vitro Cyanide Detection

Abstract The controlled synthesis of multicomponent metal–organic frameworks (MOFs) allows for the precise placement of multiple cooperative functional groups within a framework, leading to emergent synergistic effects. Herein, we demonstrate that turn‐on fluorescence sensors can be assembled by combining a fluorophore and a recognition moiety within a complex cavity of a multicomponent MOF. An anthracene‐based fluorescent linker and a hemicyanine‐containing CN − ‐responsive linker were sequentially installed into the lattice of PCN‐700. The selective binding of CN − to hemicyanine inhibited the energy transfer between the two moieties, resulting in a fluorescence turn‐on effect. Taking advantage of the high tunability of the MOF platform, the ratio between anthracene and the hemicyanine moiety could be fine‐tuned in order to maximize the sensitivity of the overall framework. The optimized MOF‐sensor had a CN − ‐detection limit of 0.05 μ m , which is much lower than traditional CN − fluorescent sensors (about 0.2 μ m ).

Li, Jialuo↗
DOE OSTI2024

Designer Fluorescent Redoxmer Self‐Reports Side Reactions in Nonaqueous Redox Flow Batteries

The state of health (SOH) is a critical measure for evaluating and predicting performance of redox flow batteries (RFBs). However, diagnosing SOH of RFBs is often challenging due to the overwhelming complexity of the electrolytes and associated electrochemical reactions. Designing active molecules or redoxmers that can autonomously exhibit property changes upon specific stimuli may provide a viable way for early diagnosis of SOH. Herein, a dimerized redoxmer, DGL-N-CH 3 , was designed and synthesized by linking blue-green fluorescent monomers through a diglycolamide linker. While DGL-N-CH 3 still maintains similar electrochemical behavior and strong fluorescence, we observe a unique side reaction when cycling DGL-N-CH 3 in H-cells, which leads to a side product, NHCH 3 -BzNSN via linker cleavage. Interestingly, NHCH 3 -BzNSN also emits fluorescence but at a longer wavelength. By taking advantage of this unique fluorescent change that corresponds to the growth of NHCH 3 -BzNSN, we successfully established the capacity decay of DGL-N-CH 3 H-cell cycling, exemplifying a proof-of-concept self-reporting redoxmer design towards in situ SOH monitoring.

25 ENERGY STORAGE↗
DOE OSTI2023

Lignin-based carbon quantum dots with high fluorescence performance prepared by supercritical catalysis and solvothermal treatment for tumor-targeted labeling

The poor fluorescence performance of lignin-based carbon quantum dots (L-CQDs) prepared using the bottom-up method has hindered their development. Here, in this study, a two-step strategy was proposed to efficiently enhance the fluorescence properties of L-CQDs. Lignin was first cracked using an ethanol supercritical/noble metal catalyst; then, the L-CQDs were prepared with the cracked lignin fragments as carbon precursors without adding any modified reagents. Compared with the OL-CQDs prepared by the traditional one-pot hydrothermal method, the L-CQDs-1 prepared from CL-1 containing much low molecular weight compounds, and have photoluminescence (increased from 63 to 975) and excellent up-conversion photoluminescence (enhanced by 16.3 to 963), which significantly enhanced by about 15 times and 60 times, respectively. They can emit bright blue fluorescence under both ultraviolet and near-infrared light irradiation owing to a large amount of surface defects caused by the rich compound composition. When L-CQDs-1 were combined with, and quenched by folic acid (FA), the prepared FA@L-CQDs-1 show the ability to target and label tumor cells. This study opens new avenues for the preparation of L-CQDs with high fluorescence performance using lignocellulosic material without heteroatom additives.

59 BASIC BIOLOGICAL SCIENCES↗