Dual‐wavelength excitation for fluorescence‐based quantification of zinc protoporphyrin IX and protoporphyrin IX in whole blood

Hennig, Georg; Gruber, Christian J.; Vogeser, Michael; Stepp, Herbert; Dittmar, Stephan; Sroka, Ronald; Brittenham, Gary M.

doi:10.1002/jbio.201200228

Cited by 19 publications

(18 citation statements)

References 48 publications

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“…Washing the red blood cells is known to improve the precision of measurements by the conventional haematofluorometer 24 , but requires additional laboratory facilities and trained personnel. As shown in a previous study, the dual-wavelength excitation method effectively reduces plasma bilirubin fluorescence 19 . The spectral fitting algorithm, by eliminating unstructured background fluorescence in the difference spectrum, likely suppresses interference from medications and other components in the plasma or bound to erythrocyte membranes, but this effect has not been systematically examined.…”

Section: Discussionsupporting

confidence: 60%

“…To quantitatively extract the zinc protoporphyrin fluorescence in the presence of this very large background, we acquire additional fluorescence spectra excited at a wavelength of 407 nm (ref. 19 ). Both spectra are obtained with an excitation power of ∼2.5 mW for the illuminated area of 1-mm diameter to comply with the light-exposure limits defined by the international standard IEC 60825-1:2014.…”

Section: Resultsmentioning

confidence: 99%

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Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

et al. 2016

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Worldwide, more individuals have iron deficiency than any other health problem. Most of those affected are unaware of their lack of iron, in part because detection of iron deficiency has required a blood sample. Here we report a non-invasive method to optically measure an established indicator of iron status, red blood cell zinc protoporphyrin, in the microcirculation of the lower lip. An optical fibre probe is used to illuminate the lip and acquire fluorescence emission spectra in ∼1 min. Dual-wavelength excitation with spectral fitting is used to distinguish the faint zinc protoporphyrin fluorescence from the much greater tissue background fluorescence, providing immediate results. In 56 women, 35 of whom were iron-deficient, the sensitivity and specificity of optical non-invasive detection of iron deficiency were 97% and 90%, respectively. This fluorescence method potentially provides a rapid, easy to use means for point-of-care screening for iron deficiency in resource-limited settings lacking laboratory infrastructure.

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Section: Discussionsupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

et al. 2016

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“…The application of dual-wavelength excitation in the HF technique [24] allowed the recording of background fluorescence, which then could be removed from the analyte spectra [27]. In 2019, it was shown that even the non-invasive measurement of erythrocyte ZnPPIX in children and women after childbirth was possible on the wet vermillion of the lower lip using this principle [28,29].…”

Section: Spectrophotometry and -Fluorometrymentioning

confidence: 99%

Protoporphyrin IX Analysis from Blood and Serum in the Context of Neurosurgery of Glioblastoma

Walke¹,

Molina²,

Stummer³

et al. 2021

Mass Spectrometry in Life Sciences and Clinical Laboratory

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Protoporphyrin IX (PPIX) is formed from δ-aminolevulinic acid (ALA) during heme biosynthesis. Due to its cyclic tetrapyrrole core structure, it absorbs in the visible region of the electromagnetic spectrum and is thus colored. Both ALA and PPIX have become of great interest to neurosurgery, because in high-grade glioma, ALA diffuses into the tumor and is converted to PPIX. Fluorescence-guided resection (FGR) takes advantage of both the enrichment of PPIX in the tumor and its fluorescent properties, which enable visualization of tumor tissue. ALA-mediated FGR thus maximizes the extent of resection with better prognosis for patients. Tumor cells are able to produce porphyrins naturally or after administration of ALA, which is also reflected in elevated plasma fluorescence of cancer patients. PPIX might thus serve as a biomarker for monitoring of the tumor burden. A liquid chromatography-mass spectrometry (LC-MS)-based method is presented to quantify PPIX in blood and serum in the context of current fluorescence-based diagnostics. The method is able to distinguish between zinc PPIX, a component of red blood cells of importance in the detection of lead poisoning and iron deficiency anemia, and metal-free PPIX. In a proof-of-principle study, it was used to follow a time course of a glioblastoma patient undergoing surgery and confirmed elevated PPIX blood levels before ALA administration. During surgery, these blood levels increased about four-fold. The here developed 10 min reversed-phase LC-target MS method now allows patient screening with high specificity and throughput.

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“…Notably, our TIRF study, carried out with an excitation wavelength of 405 nm, reveals the emergence of autofluorescence in dried smears. This wavelength was chosen to be in resonance with the strongest absorption peak in protoporphyrin IX, which plays an important part in the biosynthesis of heme [15,16]. Our measurement samples were parasite enriched smears on cover slips, which were prepared from cultures treated with Percoll (see ).…”

Section: Morphological Changes In Infected Rbcsmentioning

confidence: 99%

Dissection ofPlasmodium falciparumdevelopmental stages with multiple imaging methods

Preißinger¹,

Vértessy

Kézsmárki

2020

Preprint

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Efficient malaria treatment is a global challenge, requiring in-depth view into the maturation of malaria parasites during the intraerythrocytic cycle. Exploring structural and functional variations of the parasites through the intraerythrocytic stages and their impact on red blood cell (RBCs) is a cornerstone of antimalarial drug development. In order to trace such changes in fine steps of parasite development, we performed an imaging study of RBCs infected by Plasmodium falciparum, using atomic force microscopy (AFM) and total internal reflection fluorescence microscopy (TIRF), further supplemented with bright field microscopy for the direct assignment of the stages. This multifaceted imaging approach allows to reveal structure–functionality relations via correlations of the parasite maturation with morphological and fluorescence properties of the stages. We established identification patterns characteristic to the different parasite stages based on the height profile of infected RBCs, as obtained by AFM, which show close correlation with typical fluorescence (TIRF) maps of RBCs. Furthermore, we found that hemozoin crystals exhibit a strong optical contrast by quenching fluorescence. We demonstrate that these topographic and optical features also provide a tool to locate the hemozoin crystals within the RBCs and, in turn, to follow their growth.

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Dual‐wavelength excitation for fluorescence‐based quantification of zinc protoporphyrin IX and protoporphyrin IX in whole blood

Cited by 19 publications

References 48 publications

Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

Protoporphyrin IX Analysis from Blood and Serum in the Context of Neurosurgery of Glioblastoma

Dissection ofPlasmodium falciparumdevelopmental stages with multiple imaging methods

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