Fluorescein Research Articles

Turning Waste into Treasure: Functionalized Biomass-Derived Carbon Dots for Superselective Visualization and Eradication of Gram-Positive Bacteria.

Gram-positive bacteria pose significant threats to human health, necessitating the development of targeted bacterial detection and eradication strategies. Nevertheless, current approaches often suffer from poor targeting specificity. Herein, the study utilizes purple rice lixivium to synthesize biomass carbon dots (termed BCDs) with wheat germ agglutinin-like residues for precisely targeting Gram-positive bacteria. Subsequently, fluorescein isothiocyanate (FITC) molecules are grafted onto BCDs to yield FITC-labeled BCDs (termed CDFs), which can selectively and rapidly (≤5 min) stain bacterial cell wall and particularly target the peptidoglycan component. Strikingly, CDFs achieve superselective visualization of Gram-positive bacteria even in the presence of mammalian cells and Gram-negative bacteria. Furthermore, protoporphyrin (PpIX) molecules are conjugated onto BCDs to yield PpIX-modified BCDs (termed CDPs), which can induce bacterial aggregation and in situ generate singlet oxygen for realizing enhanced antibacterial photodynamic therapy (PDT). At the minimum bactericidal concentration of CDPs (PpIX: 5 µgmL-1), CDP-mediated PDT disrupts bacterial structure and metabolism pathways, thereby affecting bacterial interactions to eradicate biofilms. Importantly, CDP-mediated PDT efficiently modulates antiinflammatory responses to promote wound healing in the bacteria-infected mice. This study underscores the significance of harnessing renewable and cost-effective biomass resources for preparing Gram-positive bacteria-targeting theranostic agents, which may find potential clinical applications in the future.

Intraoperative ex-vivo epifluorescent diagnostics of stereotactic brain biopsies using EndoScell scanner: diagnostic accuracy study.

Brain biopsy is commonly employed for the histological diagnosis of complex intracranial diseases. To improve the positive diagnostic rate, the precision of intraoperative tissue sampling is critical. This study evaluated the accuracy of fluorescence imaging technology in rapidly distinguishing tumours from nontumour tissue during surgery, thus providing real-time feedback to surgeons and optimizing the surgical workflow. Biopsy samples from 65 patients were selected for this study. The lesion tissues were sequentially stained with sodium fluorescein and methylene blue, followed by fluorescence imaging via a handheld EndoScell scanner under an intraoperative cellular microscope. Frozen section examinations and haematoxylin-eosin (HE) staining were performed on the same lesion tissue by the pathology department. The time required for fluorescence imaging and pathology of frozen sections was recorded. The results of fluorescence imaging (whether the tissue was a tumour or nontumour tissue) and frozen pathology (whether the tissue was a tumour or nontumour tissue) were also recorded. The HE staining results were used as the final gold standard for diagnosis. The sensitivity, specificity, area under the curve (AUC), Kappa consistency test, and diagnostic efficiency of both methods were calculated. Lesion tissue and diagnostic results were successfully obtained from all 65 patients. When HE-stained histopathology was used as the gold standard, the sensitivity of fluorescence imaging was 100% (95% CI: 0.917-1.000), and the specificity was 63.6% (95% CI: 0.316-0.876). In comparison, the sensitivity of frozen section pathology was 88.9% (95% CI: 0.767-0.954), and the specificity was 100% (95% CI: 0.679-1.000). Both methods demonstrated high diagnostic accuracy. ROC curve analysis revealed that the AUCs for fluorescence imaging and frozen pathology were 0.818 and 0.944, respectively, with no significant difference observed in diagnostic performance (Z = 1.597, P > 0.05). Kappa consistency tests indicated that the Kappa value for frozen pathology compared with HE staining was 0.730 (P < 0.001); for fluorescence imaging compared with HE staining, the Kappa value was 0.744 (P < 0.001), thus demonstrating strong agreement with the HE staining results for both methods. In terms of time efficiency, fluorescence imaging was significantly faster than frozen section pathology [6 (4, 7) min vs. 48 (46, 55) min, Z=-9.856, P < 0.001], thus showing a clear advantage regarding time efficiency for fluorescence imaging. Intraoperative fluorescence imaging via an EndoScell scanner, which represents a novel method for histopathological diagnosis, has high diagnostic accuracy and efficiency. This method provides real-time guidance for tissue sampling strategies in brain biopsy, thereby improving the positive diagnostic rate and reducing surgical risk.

Fluorescein-based SynNotch adaptors for regulating gene expression responses to diverse extracellular and matrix-based cues

Synthetic Notch (SynNotch) receptors function like natural Notch proteins and can be used to install customized sense-and-respond capabilities into mammalian cells. Here, we introduce an adaptor-based strategy for regulating SynNotch activity via fluorescein isomers and analogs. Using an optimized fluorescein-binding SynNotch receptor, we describe ways to chemically control SynNotch signaling, including an approach based on a bio-orthogonal chemical ligation and a spatially controllable strategy via the photo-patterned uncaging of an o-nitrobenzyl-caged fluorescein conjugate. We further show that fluorescein-conjugated extracellular matrix (ECM)-binding peptides can be used to regulate SynNotch activity depending on the folding state of collagen-based ECM networks. To demonstrate the utility of these tools, we apply them to activate dose-dependent gene expression responses and to induce myogenic-like phenotypes in multipotent fibroblasts with spatiotemporal and microenvironmental control. Overall, we introduce an optimized fluorescein-binding SynNotch as a versatile tool for regulating transcriptional responses to ligands based on the clinically-approved fluorescein dye.

Quantifying tear exchange during rigid contact lens wear using corneoscleral profilometry: A proof of concept study.

Tear exchange during contact lens wear is essential for ocular surface integrity, facilitating debris removal, and maintaining corneal metabolism. Fluorophotometry and fluorogram methods are typically used to measure tear exchange, which require hardware modifications to a slit lamp biomicroscope. This manuscript introduces an alternative method using a corneoscleral profilometer, the Eye Surface Profiler (ESP), to quantify tear exchange during corneal and scleral rigid lens wear by assessing fluorescence intensity changes over time. As a proof of concept, a healthy participant wore a corneal and a scleral rigid lens on separate days. After lens application, 2% sodium fluorescein was instilled, and ESP images were captured at intervals over a 30-min period for corneal and a 90-min period for the scleral lens. Fluorescence intensity data were extracted and analysed using MATLAB, restricted to a region of interest centred on the contact lens. The fluorescence intensity was fitted with an exponential decay curve to quantify tear exchange. Fluorescence intensity decreased over time for both lenses, with a faster decay rate being observed for the corneal lens. The scleral lens showed an initial ingress of fluorescein into the fluid reservoir, then a slow decay in fluorescence intensity due to limited tear exchange. The decay rate for the corneal lens was approximately four times faster than the scleral lens, with the time to reach 50% decay of ~42 min for the corneal lens compared to ~157 min for the scleral lens. A new method was developed to quantify tear exchange using a commercially available corneoscleral profilometer, offering a wider field of view than existing techniques. This approach has clinical potential in scleral lens practice for identifying landing zone misalignment and improving the understanding of post-lens tear dynamics, particularly in cases involving scleral lens modifications or patients experiencing midday fogging.

Subcytotoxic transepidermal delivery using low intensity cold atmospheric plasma

Cold atmospheric plasma (CAP) has been utilized in various medical devices using its oxidative nature. Recent studies have provided evidence that CAP can facilitate the delivery of large, hydrophilic molecules through the epidermis to the dermis. On the other hand, a new approach called low-intensity CAP (LICAP) has been developed, allowing the plasma level to be controlled within a subtoxic range, thereby demonstrating various biological benefits without tissue damage. However, the ability of LICAP to enhance transepidermal delivery in sub-cytotoxic conditions has not been fully investigated. This study aims to determine the sub-cytotoxic range of exposure time for LICAP and, within the range, to investigate the effects of LICAP treatment on transepidermal drug delivery (TED) and mechanisms using human keratinocytes and a mouse model. For the in vitro studies, LICAP treatment was evaluated in human keratinocyte (HaCaT) cells by assessing reactive species production, DNA damage, and cytotoxicity profiles. Within the determined safety range, mechanistic analyses were conducted to examine LICAP-enhanced delivery pathways. mRNA expression and protein levels of tight and adherens junction genes were quantified, and changes in ultramicroscopic morphology of HaCaT monolayers were investigated. Intracellular delivery of fluorescein isothiocyanate (FITC)-dextran was also assessed. For the in vivo studies, E-cadherin expression and the transepidermal delivery (TED) of human epidermal growth factor (hEGF) were analyzed in LICAP-treated mouse dorsal skin. The upper safety range of LICAP exposure time, reducing cell viability by 70% (IC70 or LD30), was estimated at 34.3 s. Within the safety range, LICAP treatment downregulated multiple tight and adherens junction genes in HaCaT cells. Consistent with the in vitro results, the epidermal E-cadherin expression was reduced, and human epidermal growth factor (hEGF) was infiltrated in the dermis of the LICAP-treated mouse skin. Intercellular clefts were detected in the HaCaT cell monolayer immediately following LICAP treatment and intracellular delivery of FITC-dextran was confirmed after LICAP exposure. This study demonstrated that LICAP treatment enhances transepidermal permeation of hEGF, apparently via both paracellular and transcellular routes. Under our study conditions, LICAP treatment seems to be a novel approach to facilitate TED with low safety concerns in vitro. Further translational studies are needed for clinical evaluation.

Optimizing hydrophilic drug incorporation into SEDDS using dry reverse micelles: a comparative study of preparation methods.

It was the aim of this study to compare two different dry reverse micelle (RM) preparation methods for the incorporation of hydrophilic drugs into oral self-emulsifying drug delivery systems (SEDDS). Cationic ethacridine lactate, anionic fluorescein sodium salt and the antibiotic peptide bacitracin were solubilized in RM containing sodium docusate, soy phosphatidylcholine and sorbitan monooleate in highly lipophilic oils such as squalane. In the dry addition (DA) method, drugs were directly added to empty RM in their powder form. In the organic solvent-aided (OS) method, drugs were pre-dissolved in ethanol or 2-propanol, which were then evaporated to form loaded dry RM. RM with sorbitan monooleate prepared via the DA method yielded up to 2.7-fold higher solubility only for bacitracin compared to the OS method. In contrast, OS-RM with sodium docusate and soy phosphatidylcholine exhibited significantly higher drug solubilities, achieving up to 109-fold, 44-fold and 97-fold increase for ethacridine, fluorescein and bacitracin, respectively. For all model drugs, the logDlipophilic phase/water was highest for RM comprising sorbitan monooleate, with a slight increase for OS-RM. This was consistent with the release profiles from SEDDS, showing an enhanced retention when loaded with OS-RM. While DA-RM showed no significant difference in cellular uptake, it was 1.6-fold higher in OS-RM loaded squalane-based SEDDS. The DA method is an easier approach for incorporating hydrophilic drugs into dry RM. However, the OS method presents a more promising alternative as it significantly enhanced the solubility and retention of these drugs in highly lipophilic formulations.

Artemisia capillaris with two novel active compounds, Kawarayomogin I and II, inhibits HYBID (KIAA1199) expression as well as hyaluronic acid degradation

Hyaluronic acid (HA) is an important component of the skin’s extracellular matrix, and its degradation leads to wrinkles. Hyaluronan-binding protein involved in hyaluronan depolymerization (HYBID) is the main factor responsible for HA degradation in dermis. This study aimed to identify natural plant materials that can effectively suppress HYBID expression and protect HA from degradation. Screening of various plant extracts was performed for the inhibition of histamine-induced mRNA expression of HYBID in normal human dermal fibroblasts (NHDF). The molecular size distribution of HA was evaluated by incubating fluorescein isothiocyanate (FITC)-labeled large HA (1200–1600 kDa) in NHDF for certain time followed by measuring different sizes of FITC-labeled HA in the cultured medium by HPLC. Among 380 plant extracts, we found that Artemisia capillaris flower extract (ACFE) was the most effective agent in both suppressing HYBID expression as well as protecting large HA from degradation. Subsequent mechanism elucidation studies showed that ACFE epigenetically regulates the expression of HYBID by modulating the expression of a specific miRNA, miR-486-5p, which is known to directly target and inhibit HYBID expression. Our active compound search identified 1-caffeoyl-3-hydroxybutane and 3-caffeoyl-1-hydroxybutane in ACFE as new compounds, which we named Kawarayomogin I and Kawarayomogin II, respectively. This is the first report to show that Artemisia capillaris with two novel active compounds inhibits HYBID expression as well as hyaluronic acid degradation, and therefore, could be used as possible agent for cosmeceutical potential.

Apolipoprotein А-I as a transport form of cytostatics in Ehrlich ascitic carcinoma cells

One of the pressing issues of modern pharmacology remains the development of drugs with targeted antitumor action, or the creation of dosage forms of selective action of already known cytostatics in order to increase the effectiveness of chemotherapy and reduce the overall toxic effect on the body. In this work, it is proposed to use apolipoprotein A-I as a transport form of the antitumor drugs actinomycin D, doxorubicin, vinblastine and melphalan. Material and methods. Apolipoprotein A-I was isolated from the high-density lipoprotein fraction of human blood plasma. Apolipoprotein A-I was labeled with 1 % fluoresceinisothiocyanate (FITC). For the experiments, we used male C57Bl mice weighing 20–25 g. Ehrlich ascites carcinoma cells were obtained from peritoneal exudate 9–10 days after transplantation. Fluorescent analysis was carried out on an AxioImager Z1 “Zeiss” microscope using an AxioCamMRc digital camera and AxioVision V.4.5 software. The absorption spectra of antitumor drugs in the optical region of electromagnetic radiation were studied using an Evolution 300 spectrophotometer (Thermo Fisher Scientific, USA). Results. The paper presents the results indicating the ability of FITC-labeled apolipoprotein A-I to enter tumor cells. Using the method of column chromatography and spectrofluorimetry, the formation of apolipoprotein A-Icytostatic complex (actinomycin D, doxorubicin, melphalan, vinblastine) was shown. Analysis of the content of drugs in tumor cell lysates showed that absorption (internalization) was more pronounced during incubation of cells with cytostatics in complex forms with apolipoprotein A-I compared with the absorption of cytostatics by cells without a carrier. Conclusions. It has been established that apolipoprotein A-I can be a direct carrier of cytostatics into the cells of Ehrlich ascites carcinoma.

Nonreceptor tyrosine kinase ABL1 regulates lysosomal acidification by phosphorylating the ATP6V1B2 subunit of the vacuolar-type H+-ATPase

ABSTRACT The vacuolar-type H+-ATPase (V-ATPase) is a proton pump responsible for controlling the intracellular and extracellular pH of cells. Its activity and assembly are tightly controlled by multiple pathways, of which phosphorylation-mediated regulation is poorly understood. In this report, we show that in response to starvation stimuli, the nonreceptor tyrosine kinase ABL1 directly interacts with ATP6V1B2, a subunit of the V1 domain of the V-ATPase, and phosphorylates ATP6V1B2 at Y68. Y68 phosphorylation in ATP6V1B2 facilitates the recruitment of the ATP6V1D subunit into the V1 subcomplex of V-ATPase, therefore potentiating the assembly of the V1 subcomplex with the membrane-embedded V0 subcomplex to form the integrated functional V-ATPase. ABL1 inhibition or depletion impairs V-ATPase assembly and lysosomal acidification, resulting in an increased lysosomal pH, a decreased lysosomal hydrolase activity, and consequently, the suppressed degradation of lumenal cargo during macroautophagy/autophagy. Consistently, the efficient removal of damaged mitochondrial residues during mitophagy is also impeded by ABL1 deficiency. Our findings suggest that ABL1 is a crucial autophagy regulator that maintains the adequate lysosomal acidification required for both physiological conditions and stress responses. Abbreviation: ANOVA: analysis of variance; Baf A1: bafilomycin A1; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; CRK: CRK proto-oncogene, adaptor protein; CTSD: cathepsin D; DMSO: dimethylsulfoxide; EBSS: Earle’s balanced salt solution; FITC: fluorescein isothiocyanate; GFP: green fluorescent protein; GST: glutathione S-transferase; LAMP2: lysosomal associated membrane protein 2; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; PD: Parkinson disease; PLA: proximity ligation assay; RFP: red fluorescent protein; WT: wild-type.

Enhanced Linear, Nonlinear Optical, and Modulus Dielectric Properties of Fluorescein Sodium Salt Dye Embedded Within Epoxy Resin Composite Materials for Renewable Energy Applications

Enhanced Linear, Nonlinear Optical, and Modulus Dielectric Properties of Fluorescein Sodium Salt Dye Embedded Within Epoxy Resin Composite Materials for Renewable Energy Applications

Easy to use particle-mediated transport of various dissolved active agents into the hair follicles - A novel platform technology.

The use of nanoparticulate systems for the transport of active ingredients into hair follicles has been researched for almost two decades, resulting in countless publications with a wide variety of particle types, release mechanisms and active ingredients. The production of a stable dispersion is often time-consuming and costly. In this publication, we demonstrate for the first time that simply adding diverse submicron particles to a drug solution significantly increases follicular penetration depth by over 160% to 190%, allowing the targeting of subinfundibular structures. Our results indicate that the increase in follicular penetration is independent of the type or sphericity of the particles (nanocrystals (NC) or lipid submicron particles (LN)). Furthermore, this principle can be used with both small molecules and large molecule therapeutics, as demonstrated with the model drugs fluorescein sodium, 6-carboxyfluorescein, green fluorescent protein and FITC-BSA. This highlights the high versatility of this new formulation principle. The system may be used for various hair follicle-associated diseases such as alopecia or for the preoperative disinfection of hair follicles and the transfollicular transport of active pharmaceutical and/or cosmetic ingredients.

Visible Light Spectroscopy of Liquid Solutes from Femto- to Attoliter Volumes Inside a Single Nanofluidic Channel.

UV-vis spectroscopy is a workhorse in analytical chemistry that finds application in life science, organic synthesis, and energy technologies like photocatalysis. In its traditional implementation with cuvettes, it requires sample volumes in the milliliter range. Here, we show how nanofluidic scattering spectroscopy (NSS), which measures visible light scattered from a single nanochannel in a spectrally resolved way, can reduce this sample volume to the attoliter range for solute concentrations in the mM regime, which corresponds to as few as 105 probed molecules. The connection of the nanochannel to a microfluidic in-and-outlet system enables such measurements in continuous flow conditions, and the integrated online optical reference system ensures their long-term stability. On the examples of the nonabsorbing solutes NaCl and H2O2 and the dyes Brilliant Blue, Allura Red, and Fluorescein, we demonstrate that spectral fingerprints can be obtained with good accuracy and that solute concentrations inside the nanochannel can be determined based on NSS-spectra. Furthermore, by applying a reverse Kramers-Kronig transformation to NSS-spectra, we show that the molar extinction coefficient of the dye solutes can be extracted in good agreement with the literature values. These results thus advertise NSS as a versatile tool for the spectroscopic analysis of solutes in situations where nanoscopic sample volumes, as well as continuous flow measurements are critical, e.g., in single particle catalysis or nanoscale flow cytometry.

Pulsed Ultrasound-Mediated Drug Delivery Enhancement Through Human Sclera.

The purpose of this study was to characterize whether pulsed ultrasound (PUS) affects transscleral drug delivery. Fluorescein sodium (NaF, 376 Da) and fluorescein isothiocyanate-conjugated dextran 40 (FD-40, 40 kDa) were used as model drugs. Human sclera grafts were placed in modified Franz diffusion cells and were treated by PUS (1 megahertz [MHz], 0.71W/cm2, duty cycle 30%, application time 5minutes) once or repeatedly under various conditions to assess permeation enhancement and reservoir effect. The safety of PUS application was assessed on human sclera grafts ex vivo and rabbit eyes in vivo by histology and temperature measurements. Single PUS application yielded a significant increase in FD-40 permeation (P< 0.05). Repeated PUS applications led to a further enhancement in FD-40 permeation and also significantly promoted NaF permeation (more than 8.51-fold, P< 0.05). The human scleral permeability was temporarily modified by PUS, as evidenced by the increased scleral permeability during PUS application and the unchanged permeability coefficients at steady state. The reservoir effect of human sclera was also enhanced by PUS application. Cavitation was detected under PUS. A minor increase in graft temperature rise (<1°C) and no ocular damage was caused by PUS. PUS is an efficient and safe method to enhance model drugs to transport across human sclera by increasing the scleral permeability transiently and improving the reservoir effect. The enhancement was correlated with the molecule size and further promoted by the repeated PUS application. Our study provides proof of concept for using PUS to enhance drug delivery to the posterior eye segment.

Direct covalent attachment of fluorescent molecules on plasma polymerized nanoparticles: a simplified approach for biomedical applications.

Polymeric nanoparticles surface functionalised with fluorescent molecules hold significant potential for advancing diagnostics and therapeutic delivery. Despite their promise, challenges persist in achieving robust attachment of fluorescent molecules for real-time tracking. Weak physical adsorption, pH-dependent electrostatic capture, and hydrophobic interactions often fail to achieve stable attachment of fluorescent markers. While covalent attachment offers stability, it often entails laborious multi-step wet-chemistry processes. This work demonstrates that plasma polymerised nanoparticles (PPNs) can directly and covalently attach fluorescent molecules with no need for additional interim treatment processes. For the first time, we provide evidence indicating the formation of covalent bonds between the fluorescent molecules and PPN surfaces. Two model fluorescent molecules, fluorescein isothiocyanate (FITC) and Nile blue (NB), were attached to PPNs in a one-step process. The attached molecules remained on nanoparticle surfaces even after detergent washing, as confirmed by a combination of X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, flow cytometry, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) data. The robust attachment of fluorescent molecules on PPNs ensures their stability and functionality, enhancing the potential of these fluorescently labelled nanoparticles for diagnostic, therapeutic, and imaging applications.

Gold Nanorod-Coated Hydrogel Brush Valves in Macroporous Silicon Membranes for NIR-Driven Localized Chemical Modulation.

A two-dimensional array of microfluidic ports with remote-controlled valve actuation is of great interest for applications involving localized chemical stimulation. Herein, a macroporous silicon-based platform where each pore contains an independently controllable valve made from poly(N-isopropylacrylamide) (PNIPAM) brushes is proposed. These valves are coated with silica-encapsulated gold nanorods (GNRs) for NIR-actuated switching capability. The layer-by-layer (LBL) electrostatic deposition technique was used to attach the GNRs to the PNIPAM brushes. The deposition of GNRs was confirmed by dark-field optical microscopy, and the localized surface plasmon resonance (LSPR) of the deposited GNRs was analyzed using UV-Vis spectra. To evaluate the chemical release behaviors, fluorescein dye was employed as a model substance. The chemical release properties, like OFF-state diffusion through the valve, the ratio between ON-state and OFF-state chemical release, and the rapidness of chemical modulation of the valve, were investigated, varying the PNIPAM brush thickness. The results indicate that enhancing the thickness of the PNIPAM brush in our platform improves control over the chemical modulation properties. However, excessive increases in brush length may lead to entanglement, which negatively impacts the chemical modulation efficiency.

Optimizing retinal Imaging: Evaluation of ultrasmall TiO2 Nanoparticle- fluorescein conjugates for improved Fundus fluorescein angiography

Fundus Fluorescein Angiography (FFA) has been extensively used for the identification, management, and diagnosis of various retinal and choroidal diseases, such as age-related macular degeneration, diabetic retinopathy, retinopathy of prematurity, among others. This exam enables clinicians to evaluate retinal morphology and the pathophysiology of retinal vasculature. However, adverse events, including from mild to severe reactions to sodium fluorescein, have been reported. Titanium dioxide nanoparticles (NPTiO2) have shown significant potential in numerous biological applications. Coating or conjugating these nanoparticles with small molecules can enhance their stability, photochemical properties, and biocompatibility, as well as increase the hydrophilicity of the nanoparticles, making them more suitable for biomedical applications. This work demonstrates the potential use of ultrasmall titanium dioxide nanoparticles conjugated with sodium fluorescein to improve the quality of angiography exams. The strategy of conjugating fluorescein with NPTiO2 successfully enhanced the fluorescence photostability of the contrast agent and increased its retention time in the retina. Preliminary in vivo and in vitro safety tests suggest that these nanoparticles are safe for the intended application demonstrating low tendency to hemolysis, and no significant changes in the retina thickness or in the electroretinography a-wave and b-wave amplitudes. Overall, the conjugation of fluorescein to NPTiO2 has produced a nanomaterial with favorable properties for use as an innovative contrast agent in FFA examinations. By providing a clear description of our methodology of analysis, we also aim to offer better perspectives and reproducible conditions for future research.

Fluorescence turn-on recognition of trace acetamiprid in seawater using selective molecularly imprinted polymer-based nanoprobe

A novel imprinted composite nanoprobe for fluorescence turn-on recognition of acetamiprid was fabricated and applied to rapidly and sensitively detect trace-level acetamiprid in seawater. The fluorescent probe was prepared using modified fluorescein isothiocyanate as a response unit to improve the sensitivity of signal transmission. The quantitative analysis of acetamiprid was obtained by measuring fluorescence enhancement efficiency of the probe. Under optimal conditions, a good linear relationship with a determination coefficient of 0.9988 was demonstrated in the range of 0–45 μg L−1 and the limit of detection was 1.5 μg L−1. The developed fluorescence-enhancing nanoprobe was utilized in determination of acetamiprid in seawater samples and achieved recoveries from 96.00 % to 104.00 % with the relative standard deviations <5.88 % (n = 3). This study offered a promising strategy for simple, reliable and sensitive detection of acetamiprid by embedding fluorescent dye in molecularly imprinted material as highly selective probes.

Autostable-II stent versus bicanalicular silicon intubation for management of lacrimal canalicular obstruction

Purpose To compare the anatomical and functional results of the use of Autostable-II self-retaining stent (A-II SRS) and bicanalicular silicone tube (BST) in the treatment of epiphora due to distal or common canalicular obstruction. Setting and design This prospective, comparative, interventional study was conducted at El Minia University, Faculty of Medicine, Department of Ophthalmology. Patients and methods This study included 80 eyes of 65 patients and was performed from March 2020 to June 2021 in Minia University Hospital. Detailed history taking, anterior segment examination, lacrimal probing, and syringing were done. The patients were evaluated 1 day, 1 week, 1 month, and 3 months postoperatively when A-II SRS and BST were removed and 3 months after their removal. Results Eighty eyes of 56 patients with distal canalicular obstruction were evaluated in this study. Patients in group A were treated using A-II SRS (FCI), and patients in group B were treated by BST (EAGLE LABS). Results revealed a highly statistically significant difference between the two groups in epiphora grading 1 day postoperatively (P=0.013) and no significant difference between the two groups postoperatively at 1 week, 1 month, 3 months, and 6 months. Objective improvement indicated by fluorescein dye disappearance test by the end of the follow-up period revealed no significant difference between the two studied groups (P=0.39). Regarding tube position, in group A, two (5%) stents were extruded. In group B, only one (2.5%) was prolapsed and removed by the end of the first month. Conclusion The advantage of A-II SRS set over BST intubation surgery for lacrimal canalicular obstruction is easy placement without general anesthesia. However, extra costs are needed for A-II SRS, which is an important issue in areas with low economic income.

Down-regulation of platelet-derived growth factor receptor β in pericytes increases blood-brain barrier permeability and significantly enhances α-synuclein in a Parkinson's Disease 3D cell model in vitro under hyperglycemic condition.

Parkinson's Disease (PD) often presents with a compromised blood-brain barrier (BBB), which hyperglycemia may exacerbate. Pericytes, a key cell for BBB integrity, are potential therapeutic targets for neurodegenerative disorders. Few studies have developed 3D PD cell models incorporating neurovascular units (NVU) through the co-culture of human endothelial, pericytes, astrocytes, and SH-SY5Y cells to evaluate BBB impairment and the role of pericytes under hyperglycemic condition. A 3D PD like cell model was developed using 6-OHDA-affected SH-SY5Y cells, combined with endothelial cells, pericytes, and astrocytes through the Real Architecture for Tissue (RAFT) 3D co-culture system. PD incorporating reduced (30 % and 89 %) PDGFRβ NVU (RPN) with or without hyperglycemic model (HM) were also established. BBB permeability to sodium fluorescein was assessed, and BBB impairment was evaluated using BBB-associated proteins (ZO-1, CD54, CD144), cell-specific proteins (CD31, GFAP, PDGFRβ, CD13), tyrosine hydroxylase (TH), α-synuclein, oligomeric α-synuclein, and α-synuclein (ser9). PD 3D cell models incorporating RPN with or without hyperglycemia were successfully established in vitro. Graduately increased BBB impairment was observed in PD, PD with RPN, and PD with RPN combined with HM, indicated by decreased BBB-associated and cell-specific proteins, reduced TH, and increased α-synuclein, oligomeric α-synuclein, and α-synuclein (ser9) compared to the NVU model. Reduced pericyte PDGFRβ could increase BBB permeability, accelerate PD progression, and exacerbate under hyperglycemic condition.

Theoretical Understanding of Photoluminescence and Singlet Oxygen Quantum Yields in a Few Halogenated Fluorescein Dyes.

Visible-light absorbing metal-free organic dyes are of increasing demand for various optoelectronic applications because of their great structure-function tunability through chemical means. Several dyes also show huge potential in triplet photosensitization, generating reactive singlet oxygen. Understanding the structure-property relationships of many well-known fluorescein dyes is of paramount importance in designing next-generation energy efficient dyes, which is currently limited. For example, the role of heavy atoms in the excited-state deactivations is not fully understood for these dyes. Herein, 9 halogenated (Cl, Br, I) fluorescein dyes with varied halogen concentrations and positions are studied using time-dependent range-separated hybrid combined with polarizable continuum model with water dielectric for accounting of polarization and screening effects. Excited state energies of these dyes and their deactivations via radiative and non-radiative pathways are well described using 0-0 corrected excitation energies. Calculated results are in reasonable agreement with the available experimental data. However, no systematic correlation is found between the heavy-atom effect and calculated intersystem crossing/fluorescence rates. Not surprisingly, heavy-atom effect is found to be more pronounced in iodinated dyes compared to their brominated analogues. Halogen position also plays a critical role in determining the excited-state deactivation rates. All dyes show similar fluorescence rates of ~108 . Whereas, the intersystem crossing rates are much smaller and vary from ~102 to 104 . Nevertheless, lower fluorescence quantum yields for some dyes are attributed to the large internal conversion. Microscopic understanding on the excited-state properties of several halogenated fluorescein dyes reported here will aid in developing advanced fluorescein dye based energy efficient photosensitizers and also emitters.