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[Display omitted] • Fluorophotometry has great advantages in sensing low concentration of ferric ions. • Visual detection platform is achieved via a portable colorimeter or smartphone. • The optical and visual multi-mode Fe3+ probes perform well in real water samples. Abnormal iron ions levels may lead to some diseases and serious environmental pollution. Herein, optical and visual detection strategies of Fe3+ in water based on co-doped carbon dots (CDs) were established in the present study. Firstly, a one-pot synthetic strategy for the preparation of the N, S, B co-doped CDs with a home microwave oven was developed. Secondly, the optical properties, chemical structures, and morphology of CDs were further characterized by fluorescence spectroscopy, Uv–vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscope. Finally, the results indicated that the fluorescence of the co-doped CDs was quenched by ferric ions via the static mechanism and the aggregation of CDs, accompanied by the increased red color. The multi-mode sensing strategies of Fe3+ with fluorescence photometer, UV–visible spectrophotometer, portable colorimeter and smartphone had the advantages of good selectivity, excellent stability and high sensitivity. Fluorophotometry based on co-doped CDs was a powerful probe platform for measuring lower concentrations of Fe3+ due to its higher sensitivity, better linear relationship, lower limit of detection (0.27 μM) and limit of quantitation (0.91 μM). In addition, the visual detection methods with a portable colorimeter and smartphone had been proven to be very suitable for rapid and simple sensing of higher concentrations of Fe3+. Moreover, the co-doped CDs utilized for Fe3+ probes in tap water and boiler water obtained satisfactory results. Consequently, the efficient, versatile optical and visual multi-mode sensing platform could be extended to apply such a visual analysis of ferric ions in the biological, chemical and other fields. [ABSTRACT FROM AUTHOR]

Ocular burns are ophthalmological emergencies, owing to their potentially serious visual complications. Prompt recognition, irrigation and comprehensive examination including fluorescein staining is recommended to optimise outcomes. Burns standards recommend ophthalmological services be available in a 'timely' manner. This paper is a retrospective review of facial burn admissions between November 2017 and November 2018 at the Queen Elizabeth Hospital Birmingham (QEHB), a regional burns centre in the United Kingdom. This study aims to assess referral rates to ophthalmology, timeliness of review and the proportion of patients reviewed within a 24h window. From the data available we also aim to determine the frequency of fluorescein examination. Of 88 patients admitted with facial burns, data was available for 80 patients. The majority (n=77, 87.6%) suffered thermal burns. Twenty-two (27.5%) patients were referred to ophthalmology, and 18 (22.5%) had a documented review. Mean time from admission to review was 45.0h, with 10 (52.6%) patients being seen within 24h. Of 80 patients, 50 (62.5%) patients had no documented fluorescein examination. Further prospective studies are necessary to inform clinical guidelines and optimise management of facial burns. [ABSTRACT FROM AUTHOR]

Abstract Facing the problem of a growing number of analyses, the need for using simple equipment appears. Smartphone-based optical detection is one of the most widely applied ideas nowadays. A personal device such as a smartphone equipped with a camera is affordable even in the source-limited places. After a simple modification, providing the light source of both defined properties and orientation, a smartphone may become an efficient analytical device. In this work we present a uniform methodology of such a modification, offering a complete hand-held device for fluorometric measurements. Inducing the fluorescence of the tested analytes was done by ordinary light-emitting diodes, and phone camera was used as a detector. Then the obtained images were analyzed using the RGB colour model to get proper calibration curves. The demonstration of the system performing with the use of fluorescein preceded the examples of determination of quinine, rhodamine B, riboflavin and calcein in real-life circumstances. Example determinations of the calcium ions in mineral water and riboflavin in alcoholic beverages are provided. The results obtained with the designed device are fully comparable to the ones obtained with the conventional fluorometric equipment. The presented systems allow determination of all the investigated analytes with satisfactory detection limits, in some cases down to ppb levels. Thanks to the use of LEDs, the system could be adapted for both measuring and inducing fluorescence in different analytes, characterized by various excitation wavelengths. Graphical abstract fx1 Highlights • Portable smartphone system for determination of the fluorogenic substances is demonstrated. • The analytical performance of the set up was compared to the conventional fluorimeter equipment. • Data were analyzed using the RGB model, and the results were explained according to the CMOS characteristic and sensitivity. • The practical usefulness of the system in different scenarios using real samples was confirmed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this pilot study was to evaluate tear inflow in a scleral lens system using fluorophotometry, and indirectly assess the exchange of the tear reservoir in habitual scleral lens wearers with the presence or absence of midday fogging (MDF).Methods: Habitual scleral lens wearers (n=23) and normal scleral lens neophytes (n=10) were recruited. Of the 23 habitual wearers, 11 of them experienced MDF and 12 did not have a diagnosis of MDF. Contact lens-fitting characteristics were evaluated using ocular coherence tomograpy (OCT) and biomicroscopy. High molecular weight fluorescein (FITC) Dextran was instilled into the tear reservoir beneath the scleral lens, and the tear fluid fluorescein concentration was measured using the Fluorotron fluorophotometer. Calculated fluorescein concentrations were plotted over time to measure the fluorescein decay rate of the tear fluid beneath the scleral lens, which was used to calculate the tear exchange rate.Results: There was no significant difference in tear inflow between the MDF group (mean: 0.111%) and the non-MDF group (mean: 0.417%), and there was a high amount of variability seen in the rates (p = 0.26). In addition, there was no significance between the tear reservoir thickness in the MDF (283um) and non-MDF (326um) groups (p = 0.53).Conclusions: The relationship between the amount of tear exchange during scleral lens wear and the incidence of MDF was not significant. Additional studies are needed to further examine the role of tear exchange in MDF and address the causes of variability to improve measurement techniques with fluorophotometry in the scleral lens system. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the patient-administered Optrex™ Dry Eye Blink Test against established clinical criteria for the diagnosis of dry eye disease (DED) and to evaluate its benefit in enhancing screening for DED.Methods: Eighty-seven participants aged 38 ± 17 years, (44 female) were screened for DED using the Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) diagnostic criteria. In addition to symptoms screening with the Ocular Surface Disease Index questionnaire (≥13 cut-off score for DED), these criteria required a sign of loss of homeostasis of the tear film in the form of a non-invasive tear breakup time (NIBUT) <10 s (Oculus Keratograph; K5M), an osmolarity reading ≥308 mOsm/L or an interocular difference in osmolarity of >8 (Tearlab), or ocular surface staining (>5 fluorescein corneal spots, >9 lissamine green spots or lid wiper staining [≥2 mm length & ≥25% width]) to confirm a diagnosis of DED. The self-administered Blink Test, which requires the participant to observe an image on a computer screen and report the length of time (in seconds) that they can refrain from blinking without discomfort, was repeated three times.Results: Using a cut-off time of 10 s, the Blink Test demonstrated sensitivity of 66%, specificity of 88%, and an area under the curve of 0.77 (p < 0.001), in predicting a diagnosis of DED according to the TFOS DEWS II criteria. The correlation between the Blink Test and NIBUT was r = 0.47 (p < 0.001). When combined with the screening questionnaire, the sensitivity and specificity of the Blink Test increased to 71% and 90%, respectively.Conclusion: The Blink Test offers health professionals without advanced instrumentation, as well as patients, themselves, a rapid method of identifying possible DED. [ABSTRACT FROM AUTHOR]

A highly fluorescent carbon dots were prepared by a facile one-pot hydrothermal method using degrease cotton (human waste) as the carbon source. The structure and morphology of prepared C-dots were characterized by fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The as-prepared C-dots exhibit excellent emission property, high stability and have a narrow size distribution of 2–4 nm in diameter. Moreover, it is attractive that C-dots can be used as an effective fluorescent probe for the detection of chromium ions with good selectivity and sensitivity in an aqueous solution. The quenching phenomenon was observed after the C-dots interacted with the metal ions; and the results showed that the optimum conditions for its interaction with chromium ions were: 4.0×10 −5 g/mL of concentration of C-dots, pH=6.5 of buffer solution, and 20 min of time. Based on the optimum conditions, a new sensitive method detecting chromium ions was established. The method has been successfully applied to detect chromium ions in water and soil samples with satisfactory results. [ABSTRACT FROM AUTHOR]

1-(2,5-Dimethylfuran-3-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one (DFTP) was prepared by the reaction of 2,4,5-trimethoxybenzaldehyde and 3-acetyl-2,5-dimethyfuran. Various spectroscopic techniques including EI-MS, FT-IR, 1 H-NMR, 13 C-NMR spectral and elemental analysis were applied to confirm the structure of DFTP. The effect of different solvents with DFTP has been observed by the electronic absorption and emission spectroscopy. The resulting red shift obtained in the emission spectrum of DFTP as solvent polarity increases, represents a large change in dipole moment of DFTP molecule upon excitation due to intramolecular charge transfer in excited DFTP. Excited state intermolecular hydrogen bonding affects the energy of emission spectrum and fluorescence quantum yield of DFTP molecule. The DFTP dye undergoes solubilization in different micelles and may be used as a probe to determine the critical micelle concentration (CMC) of SDS and CTAB. The photoreactivity and net photochemical quantum yield (ϕ c ) of DFTP are determined in different solvents such as CHCl 3 , CH 2 Cl 2 , CCl 4 , and DMSO. The DFTP dye is relatively photostable in DMSO and displays photodecomposition in chloromethane solvents. [ABSTRACT FROM AUTHOR]

A new and facile method for the determination of critical micelle concentration (CMC) of ionic and non-ionic surfactants is proposed in this article. Carbon dots exhibited substantial fluorescence and therefore enhanced the sensitivity of this evaluation. Understanding the formation of surfactant micelles is vital for the applications of biomedicine such as drug fabrication and smart molecular vehicles in delivering therapeutic dosage to various molecular sites. The fluorescence property of carbon dots was utilized for the first time to estimate the critical micelle concentration of surfactants. The central concept of the approach is based on the Stokes shift determination of a system composed of constant amount of carbon dots with varying concentrations of ionic and non-ionic surfactants. The synthesized carbon dots were characterized by FTIR, TEM, XRD, Raman, UV, and fluorescence spectroscope. The carbon dots were excited at 280 nm so as to obtain maximum emission for the Stokes shift measurement. The CMC value of cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS), Triton X-100, dodecyldimethyl(3-sulfopropyl)ammonium hydroxide (SB-12) evaluated by this approach was found to be 0.98, 7.3, 0.19, and 3.5 mM, respectively. The signals of spectra were assigned and explained in terms of both electron transitions between specific molecular orbital and the interaction with solvent. [ABSTRACT FROM AUTHOR]

Abstract: The luminescence of thenoyltrifluoroacetonate (TTA) coordination complexes of trivalent europium ion (Eu(III)) in aqueous solutions and in solid-state polymeric films is probed upon single- and two-photon preresonant excitation with Ti:sapphire femtosecond laser. Particularly, diamine-liganded Eu(III)(TTA)3 and poly(oxyethylene phosphate)tris(β-diketonate)Eu(III) complexes are examined aiming their possible applications as luminescent labels for sensing and imaging of biological molecules. Even at a pre-resonance, the excitation of these compounds with high-intensity, broadband light of frequency-doubled Ti:sapphire femtosecond laser centered around 400nm results in a luminescence response suitable for fluorometric applications. [Copyright &y& Elsevier]

Abstract: The luminescence of four europium thenoyltrifluoroacetonate complexes containing diamine ligands is studied in solutions. The compounds are resonantly excited in the ligand absorption band by means of high-power nanosecond UV laser pulses. Additionally, a continuous light source is also used for resonant, as well as pre-resonant excitation of the complexes. The luminescence response characterizes the synthesized europium coordination complexes as emissive compounds suitable for fluorometric applications. Related to the possible usefulness of the diamine-liganded Eu complexes as luminescent labels for sensing and imaging of biological molecules, the luminescence response of these compounds upon UV excitation was probed also in aqueous media. [Copyright &y& Elsevier]

Abstract: Background:: Systemic antihistamines such as loratadine are efficacious in the treatment of many allergic conditions. However, their use has been associated with drying effects, particularly of the ocular surface. Objective: The purpose of this study was to compare the ocular drying effects of topical treatment with epinastine hydrochloride ophthalmic solution 0.05 % twice daily and systemic treatment with loratadine 10 mg once daily in patients with seasonal allergic conjunctivitis through the use of several standard clinical tests for dry eye. Methods:: This was a single-center, 4-visit, open-label, investigator-masked crossover study in healthy adult volunteers with a history of seasonal allergic conjunctivitis. Participants received 4 days of treatment with topical epinastine administered as 1 drop per eye twice daily and 4 days of treatment with systemic loratadine once daily, with a 10-day washout between treatments. Fluorophotometry was conducted at the baseline visit, at the crossover visit, and after 4 days of each treatment to assess tear volume, tear flow, and tear turnover rate. Decreases from baseline in tear volume, tear flow, or tear turnover rate were considered indicative of a drying effect. Keratitis, global (corneal and conjunctival) fluorescein staining (scale from 0–20 points), and tear film break-up time (TFBUT) were assessed after fluorophotometry at each visit. An increase in keratitis (as measured by global fluorescein staining) and conjunctival lissamine green staining, and a decrease in TFBUT were considered further evidence of a drying effect. Results:: Eighteen subjects were enrolled in and completed the study (78% female; 94% white; age range, 18–55 years). After 4 days of twice-daily use, topical epinastine was associated with no significant changes in tear volume, tear flow, or global fluorescein staining. After 4 days of once-daily use, systemic loratadine was associated with a 33.7% reduction in tear volume (mean reduction, 4.5 μL; range, −7.53 to 22.36 μL; P < 0.05), a 35.0% reduction in tear flow (mean reduction, 0.93 μL/min; range, −2.57 to 2.73 μL/min; P < 0.05), and a 21.7% increase in global fluorescein staining (mean increase, 0.74 point; range, −2.5 to 6.5 points; P < 0.05). No significant change in TFBUT was observed with either treatment. Conclusions:: These healthy adult volunteers with a history of seasonal allergic conjunctivitis had no clinical signs of ocular drying after 4 days of twice-daily treatment with topical epinastine. After 4 days of once-daily dosing, systemic loratadine was associated with clinical signs of ocular dryness, including decreased tear volume and tear flow. Use of loratadine was also associated with an increase in global fluorescein staining, indicating an increase in ocular surface damage. [Copyright &y& Elsevier]

Purpose: Tear turnover rate (TTR) is defined as the percent decrease of fluorescein concentration in the tears per minute after the instillation of fluorescein. The purpose of this study was to examine differences in TTR in a sample with symptoms of dry eye and an asymptomatic control sample using the Fluorotron Master™ Fluorophotometer. Methods: TTR was measured using the OcuMetrics Fluorotron Master™. It measures the decay of the fluorescence of high molecular weight fluorescein FITC Dextran instilled into the tear film. Twenty participants (post-menopausal women) were enrolled in the study (10 asymptomatic (age 64.7±6.99) and 10 symptomatic (age 61.5±7.98)). Participants were grouped according to either a positive (symptomatic) or negative (asymptomatic) McMonnies Dry Eye Questionnaire, i.e., an indication of self-reported ocular dryness and the use of rewetting/lubricating drops (questions 4 and 5). TTR was measured in the afternoon only. Measurements were made on the right eye with a controlled blink rate (15 blinks/min), for up to 30 min, post-insertion of 2 μl of 2% FITC Dextran (MW 9500). The scan data were used to construct a graph of log fluorescein concentration (ng/ml) as a function of time and the TTR calculated (%/min=(1−ln (slope))×100). Results: There was a significant difference in the TTR between symptomatic and asymptomatic subjects. Mean TTR (symptomatic) was 4.89±2.74%/min (range, 2.04–11.81) and mean TTR (asymptomatic) was 11.85±3.31%/min (range, 5.76–16.45) (P<0.0001). Conclusions: Fluorophotometry may be used to demonstrate differences in the tear turnover rate in this post-menopausal group of women, with patients experiencing symptoms of dry eye having a lower TTR than the normals. [Copyright &y& Elsevier]

The aim of the study was to develop a mucoadhesive ocular insert for the controlled delivery of ophthalmic drugs and to evaluate its efficacy in vivo. The inserts tested were based either on unmodified or thiolated poly(acrylic acid). Water uptake and swelling behavior of the inserts as well as the drug release rates of the model drugs fluorescein and two diclofenac salts with different solubility properties were evaluated in vitro. Fluorescein was used as fluorescent tracer to study the drug release from the insert in humans. The mean fluorescein concentration in the cornea/tearfilm compartment as a function of time was determined after application of aqueous eye drops and inserts composed of unmodified and of thiolated poly(acrylic acid). The acceptability of the inserts by the volunteers was also evaluated. Inserts based on thiolated poly(acrylic acid) were not soluble and had good cohesive properties. A controlled release was achieved for the incorporated model drugs. The in vivo study showed that inserts based on thiolated poly(acrylic acid) provide a fluorescein concentration on the eye surface for more than 8 h, whereas the fluorescein concentration rapidly decreased after application of aqueous eye drops or inserts based on unmodified poly(acrylic acid). Moreover, these inserts were well accepted by the volunteers. The present study indicates that ocular inserts based on thiolated poly(acrylic acid) are promising new solid devices for ocular drug delivery. [Copyright &y& Elsevier]

: PurposeTo evaluate the effects of a lipophilic analog of superoxide dismutase in the treatment of persistent epithelial defects of the cornea.: DesignInterventional case series.: MethodsNineteen eyes of 19 patients with noninfectious corneal ulcers were enrolled. Patient profiles consisted of seven cases with Mooren-type peripheral ulcers, three cases with chemical or thermal burns, two cases with vernal keratoconjunctivitis, four cases with cicatricial keratoconjunctivitis, and three cases with sterile ulcers after corneal surgery. Patients consisted of 11 men and 8 women, with a mean age of 51.5 ± 17.9 years (range, 14–77). Only patients who did not respond to conventional therapy were recruited for the study. Lecithinated superoxide dismutase was applied for 2 weeks, and sketches and/or fluorescein slit micrographs were recorded before and at the end of the study. The main outcome measure was decrease in ulcer size.: ResultsAs a group, the average ulcer size relative to the entire cornea decreased from 18.2 ± 15.1% to 10.0 ± 15.0% after 2 weeks (P < .05). A dramatic effect (>90% decrease in ulcer size) was observed in eight cases (100% in six cases), whereas no apparent change was found (<30% decrease in ulcer size) in five cases. The presence of polymorphonucleocytes within the ulcerated tissue was confirmed by brush cytology.: ConclusionLecinthinated superoxide dismutase was effective in decreasing persistent epithelial defect size in a subset of patients with sterile corneal ulcers refractive to conventional therapy. A large-scale clinical investigation is merited. [Copyright &y& Elsevier]

Purpose: To determine the amount of pupillary constriction to four different concentrations of pilocarpine in normal human subjects and to determine if pupillary constriction correlates with bioavailability of the instilled concentrations. The amount of pupillary constriction to dilute pilocarpine is utilized as a diagnostic test for Adie tonic pupil as distinguished from a normal pupil response.Design: Twenty healthy volunteers had automated binocular infrared pupillography in the dark after instillation of four different concentrations of dilute pilocarpine. Ocular penetration of eye drops was also assessed using 2% fluorescein sodium as a tracer.Methods: Prospective institutional double-masked study of both eyes of twenty healthy volunteers, ten with brown irides, ten with blue irides, between the ages of 20-40 years.Results: A pilocarpine dose-dependent curve showed decreased pupil size within 15 minutes, peaking at 30-60 minutes. No difference was noted between right and left eyes, iris color, or corneal permeability.Conclusions: Normal pupils constrict to dilute concentrations of pilocarpine (0.25% or 0.125%), but constrict insignificantly to concentrations of 0.0313% or 0.0625%. Pupil constriction with 0.0625% pilocarpine should distinguish an Adie pupil from normal. This confirms the utility of this simple office diagnostic procedure. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the loss of lens transparency incurred by patients undergoing trabeculectomy. Design: A prospective cohort study. Participants and Controls: Data corresponding to 33 eyes of 33 consecutive patients with primary open-angle glaucoma (POAG) subjected to trabeculectomy (group 1) were compared with those corresponding to 12 eyes of 12 patients with POAG receiving topical antiglaucomatous treatment (group 2). Intervention: Lens fluorophotometry was performed on the group 1 patients before and 12 months after surgery. In group 2, fluorophotometry was conducted at the onset of the study and at 12 months of follow-up. Main Outcome Measures: Starting and final lens autofluorescence and transmittance values corresponding to each subject group were compared. Results: In group 1, starting and final autofluorescence was 556.3 ± 184.3 and 691.1 ± 179.3 Eq ng/ml, and starting and final transmittance was 0.78 ± 0.11 and 0.67 ± 0.14, respectively. Respective values for group 2 were 574.3 ± 94.8 and 595.2 ± 107.0 Eq ng/ml and 0.72 ± 0.17 and 0.71 ± 0.16. The mean change between final and initial autofluorescence was statistically different between groups (134.7 ± 123.7, group 1, 20.9 ± 25.1 Eq ng/ml, group 2; P < 0.001). Similarly, a significant difference (P < 0.001) in transmittance change was observed between the surgery and control groups (-0.11 ± 0.072, group 1; 0.02 ± 0.008, group 2) Conclusions: It was demonstrated by lens fluorophotometry that trabeculectomy in POAG leads to a loss in lens transparency. [ABSTRACT FROM AUTHOR]

The specific and sensitive detection of peroxynitrite (ONOO – /ONOOH) in biological systems is a great challenge due to its high reactivity towards several biomolecules. Herein, we validated the advantages of using fluorescein-boronate (Fl-B) as a highly sensitive fluorescent probe for the direct detection of peroxynitrite under biologically-relevant conditions in two different cell models. The synthesis of Fl-B was achieved by a two-step conversion synthetic route with high purity (> 99 %) and overall yield (∼ 42%). Reactivity analysis of Fl-B with relevant biological oxidants were performed. The rate constant for the reaction of peroxynitrite with Fl-Bwas 1.7 x 10 6 M -1 s -1 , a million times faster than the rate constant measured for H 2 O 2 (k = 1.7 M -1 s -1 ) and 2,700 faster than HOCl (6.2 x 10 2 M -1 s -1 ) at 37° C and pH 7.4. The reaction of Fl-B with peroxynitrite was significant even in the presence of physiological concentrations of CO 2 , a well-known peroxynitrite reactant. Experimental and simulated kinetic analyses confirm that the main oxidation process of Fl-B takes place with peroxynitrite itself via a direct bimolecular reaction and not with peroxynitrite-derived radicals. Fl-B was successfully applied for the detection of endogenously- generated peroxynitrite by endothelial cells and in macrophage-phagocyted parasites. The generated data allowed estimating the actual intracellular flux of peroxynitrite, e.g., ionomycin-stimulated endothelial cells generated peroxynitrite at a rate of ∼ 0.1 μM s -1 , while immunostimulated macrophages do so in the order of ∼ 1 μM s -1 inside T. cruzi -infected phagosomes. Cellular peroxynitrite detection was achieved by conventional laboratory fluorescence-based methods including flow cytometry and epi-fluorescence microscopy. Fl-B was shown to be more sensitive than the coumarin boronate due to a higher molar absorption coefficient and quantum yield. Overall, our results show that Fl-B is a kinetically selective and highly sensitive probe for the direct detection of cell-derived peroxynitrite. Moreover, the data allowed to tailor boronate-derivatives targeted to identify subcellular sites and rates of peroxynitrite generation; indeed, ongoing work is focused on the generation and characterization of new organelle-targeted boronate-based probes. [ABSTRACT FROM AUTHOR]