Alexa Fluor 488 as an iron sensing molecule and its application in PEBBLE nanosensors

Microfluidics Technology for the Design and Formulation of Nanomedicines

In conventional drug administration, drug molecules cross multiple biological barriers, distribute randomly in the tissues, and can release insufficient concentrations at the desired pathological site. Controlling the delivery of the molecules can increase the concentration of the drug in the desired location, leading to improved efficacy, and reducing the unwanted effects of the molecules under investigation. Nanoparticles (NPs), have shown a distinctive potential in targeting drugs due to their unique properties, such as large surface area and quantum properties. A variety of NPs have been used over the years for the encapsulation of different drugs and biologics, acting as drug carriers, including lipid-based and polymeric NPs. Applying NP platforms in medicines significantly improves the disease diagnosis and therapy. Several conventional methods have been used for the manufacturing of drug loaded NPs, with conventional manufacturing methods having several limitations, leading to multiple drawbacks, including NPs with large particle size and broad size distribution (high polydispersity index), besides the unreproducible formulation and high batch-to-batch variability. Therefore, new methods such as microfluidics (MFs) need to be investigated more thoroughly. MFs, is a novel manufacturing method that uses microchannels to produce a size-controlled and monodispersed NP formulation. In this review, different formulation methods of polymeric and lipid-based NPs will be discussed, emphasizing the different manufacturing methods and their advantages and limitations and how microfluidics has the capacity to overcome these limitations and improve the role of NPs as an effective drug delivery system.

BODIPY-Pyridylhydrazone Probe for Fluorescence Turn-On Detection of Fe3+ and Its Bioimaging Application

A novel pyridylhydrazone-tethered BODIPY (BODIPY-PH) was synthesized, fully characterized via nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopic (FTIR), and single-crystal X-ray diffraction (SC-XRD) techniques, and developed for the selective detection of Fe3+ through fluorescent enhancement process. This derivative showed 1:1 binding with Fe3+ in an acetonitrile-water mixture (1:9 v/v) with the binding constant (K) of 5.4 × 104 M−1 and the limit of detection of 0.58 µM. The Fe3+ complexation reaction has been proved to be a reversible process and could be effectively repeated up to three cycles. The electronic properties of BODIPY-PH and its Fe3+ complex modeled by the density functional theory (DFT) method suggested the presence of chelation-enhanced fluorescence (CHEF) effect in the Fe3+ binding reaction. The X-ray absorption spectroscopy (XAS) probed at Fe K-edge confirmed the complex formation between BODIPY-PH and the Fe3+ in an octahedral geometry. Finally, bioimaging against human embryonic kidney (Hek293) cell, through confocal fluorescence microscopic technique indicated that the BODIPY-PH displayed good permeability and low toxicity toward the tested cell lines and showed enhanced fluorescent signal in the cells incubated with Fe3+ proving its capability for Fe3+ analysis in cellular matrix.

Chemical Sectioning for Immunofluorescence Imaging

Immunofluorescence (IF) is a powerful investigative tool in biological research and medical diagnosis, whereas conventional imaging methods are always conflict between speed, contrast/resolution, and specimen volume. Chemical sectioning (CS) is an effective method to overcome the conflict, which works by chemically manipulating the off/on state of fluorescent materials and turning on only the extremely superficial surface fluorescence of tissues to realize the sectioning capacity of wide-field imaging. However, the current mechanism of CS is only applicable to samples labeled with pH-sensitive fluorescent proteins and still cannot fulfill samples immunolabeled with frequently used commercial fluorescent dyes. Here, immunofluorescence chemical sectioning (IF-CS) is described to present an off/on mechanism for Alexa dyes by complexation reactions, allowing CS imaging of IF labeled tissues. IF-CS enables IF freeing from out-of-focus interference in wide-field imaging and satisfying with multicolor imaging. IF-CS demonstrates the utility of the 3D submicron-resolution imaging of large immunolabeled tissues on the wide-field block-face system. IF-CS may remarkably facilitate systematic studies of refined subcellular architectures of endogenous proteins in intact biological systems.

An indolino-spironaphthooxazine probe for colorimetric detection of ferric ions in drinking water

The sensing performance of a novel indolino-spironaphthooxazine derivative (SPNO), 6′(3,4-dihydroisoquinolin-2(1H)-yl)-3,3-dimethyl-1-phenethylspiro[indoline-2,3′-naphtho[2,1-b][1,4]oxazine], was investigated for rapid colorimetric detection of ferric ions (Fe³⁺) in drinking water.

Advanced polymeric nanotechnology to augment therapeutic delivery and disease diagnosis

Therapeutic and diagnostic payloads are usually associated with properties that compromise their efficacy, such as poor aqueous solubility, short half-life, low bioavailability, nonspecific accumulation and diverse side effects. Nanotechnological solutions have emerged to circumvent some of these drawbacks, augmenting therapeutic and/or diagnostic outcomes. Nanotechnology has benefited from the rise in polymer science research for the development of novel nanosystems for therapeutic and diagnostic purposes. Polymers are a widely used class of biomaterials, with a considerable number of regulatory approvals for application in clinics. In addition to their versatility in production and functionalization, several synthetic and natural polymers demonstrate biocompatible properties that dictate their successful biological performance. This article highlights the physicochemical characteristics of a variety of natural and synthetic biocompatible polymers, as well as their role in the manufacture of nanotechnology-based systems, state-of-art applications in disease treatment and diagnosis, and current challenges in finding a way to clinics.

A selective N,N-dithenoyl-rhodamine based fluorescent probe for Fe3+ detection in aqueous and living cells

A novel N,N-dithenoyl-rhodamine based fluorescent and colorimetric Fe³⁺ probe 1 was designed and synthesized by only one step from Rhodamine B hydrazide and 2-thiophenecarbonyl chloride. The structure of probe 1 was characterized by ¹H NMR/¹³C NMR spectroscopy, IR spectroscopy, and HRMS spectrometry. Accompanying with significant changes in visual color and fluorescent spectrum, probe 1 displayed good sensitivity for Fe³⁺ with an abroad pH span. The detection limit (3.76 μmol/L, 0.2 mg/L) for Fe³⁺ was lower than WHO recommended value (0.3 mg/L) for drinking water. Using two thiophene carbonyl groups as coordinating functional recognition group, probe 1 showed excellent selectivity towards Fe³⁺ over diverse coexistent metal ions and anions. The sensing mechanism between dithenoyl-substituted probe 1 and Fe³⁺ was further confirmed by ¹H NMR and IR titration experiments, binding constants study, and Job's plot analysis. Furthermore, probe 1 also exhibited good cell membrane permeability and could be used as an efficient Fe³⁺ probe in living human cells.

Visualization of materials using the confocal laser scanning microscopy technique

The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.

Anticancer Effect of Cisplatin-Loaded Poly (Butylcyanoacrylate) Nanoparticles on A172 Brain Cancer Cells Line

Background: Drug delivery systems have been designed to achieve targeted delivery and control the release rate of the drugs. A serious challenge associated with drug delivery systems is the presence of the blood-brain barrier which limits drugs penetration. In the current study, the effects of cisplatin nanoparticles on A172 brain cancer cell line were investigated. Methods: Cisplatin nanoparticles were produced by miniemulsion polymerization technique and their properties were evaluated. Drug release assay was performed to characterize the nanoparticles’ properties. Here, we examined the effects of cisplatin nanoparticles and free form of cisplatin on A172 cancer cell line. MTT assay was performed for different concentrations of the drug. To measure the apoptosis rate in A172 cell line in the presence of cisplatin nanoparticles or its free from, Annexin V staining method was used. Results: Our results indicated that loading type of cisplatin was physical loading and only 4.7% of cisplatin was released after 68 h. Furthermore, MTT assay showed that cisplatin nanoparticles in all concentrations had more cytotoxic effects on the cells comparing with the free form of cisplatin and control groups. We also showed that cisplatin nanoparticles could increase apoptosis in cancer cells more than the drug in the free form by using flow cytometry technique. Conclusion: Overall, these findings proved that cisplatin loaded on poly (Butylcyanoacrylate) nanoparticles, was more efficient than the free form of cisplatin in treating A172 cancer cell line.

Novel Schiff base (DBDDP) selective detection of Fe (III): Dispersed in aqueous solution and encapsulated in silica cross-linked micellar nanoparticles in living cell

This work demonstrated the synthesis of (4E)-4-(4-(diphenylamino)benzylideneamino)-1,2-dihydro-1,5- dimethyl-2-phenylpyrazol-3-one (DBDDP) for Fe (III) detection in aqueous media and in the core of silica cross-linked micellar nanoparticles in living cells. The free DBDDP performed fluorescence enhancement due to Fe (III)-promoted hydrolysis in a mixed aqueous solution, while the DBDDP-doped silica cross-linked micellar nanoparticles (DBDDP-SCMNPs) performed an electron-transfer based fluorescence quenching of Fe (III) in living cells. The quenching fluorescence of DBDDP-SCMNPs and the concentration of Fe (III) exhibited a linear correlation, which was in accordance with the Stern-Volmer equation. Moreover, DBDDP-SCMNPs showed a low limit of detection (LOD) of 0.1 ppm and an excellent selectivity against other metal ions. Due to the good solubility and biocompatibility, DBDDP-SCMNPs could be applied as fluorescence quenching nanosensors in living cells.

Rhodamine based turn-on chemosensor for Fe3+ in aqueous medium and interactions of its Fe3+ complex with DNA

A novel di-coordinating rhodamine-based chemosensor, HL with NO donor atoms, selectively and rapidly recognizes Fe³⁺ in the presence of all biologically relevant as well as toxic metal ions and numerous anions and also with other reactive oxygen and nitrogen species.

A turn-on fluorogenic chemosensor for Fe3+ and a Schottky barrier diode with frequency-switching device applications

A novel highly sensitive and selective fluorescent chemosensor L has been synthesized and characterized by various physicochemical techniques.

Enhancing cell and gene therapy manufacture through the application of advanced fluorescent optical sensors (Review)

Cell and gene therapies (CGTs) are examples of future therapeutics that can be used to cure or alleviate the symptoms of disease, by repairing damaged tissue or reprogramming defective genetic information. However, despite the recent advancements in clinical trial outcomes, the path to wide-scale adoption of CGTs remains challenging, such that the emergence of a "blockbuster" therapy has so far proved elusive. Manufacturing solutions for these therapies require the application of scalable and replicable cell manufacturing techniques, which differ markedly from the existing pharmaceutical incumbent. Attempts to adopt this pharmaceutical model for CGT manufacture have largely proved unsuccessful. The most significant challenges facing CGT manufacturing are process analytical testing and quality control. These procedures would greatly benefit from improved sensory technologies that allow direct measurement of critical quality attributes, such as pH, oxygen, lactate and glucose. In turn, this would make manufacturing more robust, replicable and standardized. In this review, the present-day state and prospects of CGT manufacturing are discussed. In particular, the authors highlight the role of fluorescent optical sensors, focusing on their strengths and weaknesses, for CGT manufacture. The review concludes by discussing how the integration of CGT manufacture and fluorescent optical sensors could augment future bioprocessing approaches.

Ion-Selective Nanosensor for Photoacoustic and Fluorescence Imaging of Potassium

Ion-selective optodes (ISOs), the optical analog of ion-selective electrodes, have played an increasingly important role in chemical and biochemical analysis. Here we extend this technique to ion-selective photoacoustic optodes (ISPAOs) that serve at the same time as fluorescence-based ISOs, and apply it specifically to potassium (K⁺). Notably, the potassium ion is one of the most abundant cations in biological systems, involved in numerous physiological and pathological processes. Furthermore, it has been recently reported that the presence of abnormal extracellular potassium concentrations in tumors suppresses the immune responses and thus suppresses immunotherapy. However, unfortunately, sensors capable of providing potassium images in vivo are still a future proposition. Here, we prepared an ion-selective potassium nanosensor (NS) aimed at in vivo photoacoustic (PA) chemical imaging of the extracellular environment, while being also capable of fluorescence based intracellular ion-selective imaging. This potassium nanosensor (K⁺ NS) modulates its optical properties (absorbance and fluorescence) according to the potassium concentration. The K⁺ NS is capable of measuring potassium, in the range of 1 mM to 100 mM, with high sensitivity and selectivity, by ISPAO based measurements. Also, a near infrared dye surface modified K⁺ NS allows fluorescence-based potassium sensing in the range of 20 mM to 1 M. The K⁺ NS serves thus as both PA and fluorescence based nanosensor, with response across the biologically relevant K⁺ concentrations, from the extracellular 5 mM typical values (through PA imaging) to the intracellular 150 mM typical values (through fluorescence imaging).

A rhodamine based turn-on chemosensor for Fe3+ in aqueous medium and interactions of its Fe3+ complex with HSA

A novel hexa-coordinating rhodamine-based chemosensor, HL6, selectively and rapidly recognizes Fe³⁺ in the presence of a number of metal cations, numerous anions and amino acids in purely aqueous medium with live cell imaging applications.

Nanoparticles: Alternatives Against Drug-Resistant Pathogenic Microbes

Antimicrobial substances may be synthetic, semisynthetic, or of natural origin (i.e., from plants and animals). Antimicrobials are considered "miracle drugs" and can determine if an infected patient/animal recovers or dies. However, the misuse of antimicrobials has led to the development of multi-drug-resistant bacteria, which is one of the greatest challenges for healthcare practitioners and is a significant global threat. The major concern with the development of antimicrobial resistance is the spread of resistant organisms. The replacement of conventional antimicrobials by new technology to counteract antimicrobial resistance is ongoing. Nanotechnology-driven innovations provide hope for patients and practitioners in overcoming the problem of drug resistance. Nanomaterials have tremendous potential in both the medical and veterinary fields. Several nanostructures comprising metallic particles have been developed to counteract microbial pathogens. The effectiveness of nanoparticles (NPs) depends on the interaction between the microorganism and the NPs. The development of effective nanomaterials requires in-depth knowledge of the physicochemical properties of NPs and the biological aspects of microorganisms. However, the risks associated with using NPs in healthcare need to be addressed. The present review highlights the antimicrobial effects of various nanomaterials and their potential advantages, drawbacks, or side effects. In addition, this comprehensive information may be useful in the discovery of broad-spectrum antimicrobial drugs for use against multi-drug-resistant microbial pathogens in the near future.

Spectroscopic and nonlinear optical properties of new chalcone fluorescent probes for bioimaging applications: a theoretical and experimental study

In this study, the newly synthesized non-centrosymmetric, 4-dimethylamino-3'-isothiocyanatochalcone (PKA) compound was presented. This compound belongs to the chalcone group, and its main purpose is to be used in biomedical imaging as a fluorescence dye. For this reason, the linear and nonlinear properties in solvents of different polarity were thoroughly studied. In accordance with the requirements for a fluorochrome, the PKA compound is characterized by strong absorption, large Stokes' shifts, relatively high fluorescence quantum yields and high nonlinear optical response. Moreover, the isothiocyanate reactive probe was conjugated with Concanavalin A. Conventional fluorescence microscopy imaging of Candida albicans cells incubated with the PKA-Concanavalin A, is presented. The results of this study show that the novel conjugate PKA-Concanavalin A could be a promising new probe for cellular labelling in biological and biomedical research. Graphical abstract Spectroscopic behavior of the PKA dye.

Design and synthesis of a novel rhodamine-based chemosensor and recognition study to Fe3+

A fluorescent and colorimetric chemosensor Rh1 for Fe3+ was synthesized by condensation reaction of rhodamine B hydrochloride and 2-aminothiazole, and its structure was confirmed by NMR, IR, HRMS and crystal data. Upon coordination with Fe3+ in CH3CN-H2O (1:1, v/v) solution, the spirolactam of Rh1 is opened, which results in a dramatic enhancement of fluorescence intensity as well as the color change of the solution. Most importantly, other metal ions show no obvious interference with the detection of Fe3+. Under the optimum conditions described, the fluorescence intensity is linearly proportional to the concentration of Fe3+ in the range of 2 μm ~ 7 μm. The Job’s plot indicates a 1:1 binding stoichiometry between Rh1 and Fe3+. The association constant (Ka) is 2.26 × 104m-1.

A reversible rhodamine 6G-based fluorescence turn-on probe for Fe3+ in water and its application in living cell imaging

A reversible fluorescent probe L based on rhodamine 6G was synthesized for the optical detection of Fe³⁺ in water.

A fluorescent sensor for Cu2+and Fe3+based on multiple mechanisms

A new fluorescent sensor for the selective and sensitive sensing of Cu²⁺and Fe³⁺based on the rational control of multiple mechanisms has been developed.

Interaction of BODIPY Dyes with the Blood Plasma Proteins

Photophysical properties of several BODIPY-based fluorescent dyes were investigated in systems containing blood plasma biomolecules and in model system containing bovine serum albumin in terms of electronic absorption and fluorescence spectroscopy. The interaction between the investigated dyes and protein plasma components changes spectral characteristics of the dyes and leads to bathochromic and hypochromic absorption spectra shifts accompanied by changing of fluorescence intensity. The mechanism of fluorescence changing was defined in the terms of Stern-Volmer theory. It was shown that the static factor of molecular dye-biopolymers complex formation prevails at plasma protein concentration up to 1 g/l, while the higher viscosity range is characterized mainly by nonspecific fluorophore interactions. The increase of fluorescent characteristics of phenyl-substituted BODIPY in the presence of proteins caused by resonance energy transfer and change of physicochemical properties of the molecular environment of the fluorophore was shown for the first time.

Novel fluorescent probes based on rhodamine for naked-eye detection of Fe3+ and their application of imaging in living cells

Novel fluorescent probes for Fe³⁺ and their application of imaging in living cells.

Dual mode signaling responses of a rhodamine based probe and its immobilization onto a silica gel surface for specific mercury ion detection

The amino-ethyl-rhodamine-B based probe 2 appended with a 3-aminomethyl-(2-amino-1-pyridyl) group retained its Hg(ii)-specific chromogenic and fluorogenic signaling responses in an aqueous medium even upon immobilization onto a silica gel surface for selective detection and extraction of Hg(ii) ions.

A Highly Selective and Sensitive Turn-On Fluorescent Chemosensor Based on Rhodamine 6G for Iron(III)

Recently, more and more rhodamine derivatives have been used as fluorophores to construct sensors due to their excellent spectroscopic properties. A rhodamine-based fluorescent and colorimetric Fe(3+) chemosensor 3',6'-bis(ethylamino)-2-acetoxyl-2',7'-dimethyl-spiro[1H-isoindole-1,9'-[9H]xanthen]-3(2H)-one (RAE) was designed and synthesized. Upon the addition of Fe(3+), the dramatic enhancement of both fluorescence and absorbance intensity, as well as the color change of the solution, could be observed. The detection limit of RAE for Fe(3+) was around 7.98 ppb. Common coexistent metal ions showed little or no interference in the detection of Fe(3+). Moreover, the addition of CN(-) could quench the fluorescence of the acetonitrile solution of RAE and Fe(3+), indicating the regeneration of the chemosensor RAE. The robust nature of the sensor was shown by the detection of Fe(3+) even after repeated rounds of quenching. As iron is a ubiquitous metal in cells and plays vital roles in many biological processes, this chemosensor could be developed to have applications in biological studies.

Engineered nanoparticles: thrombotic events in cancer

Engineered nanoparticles are being increasingly produced for specific applications in medicine. Broad selections of nano-sized constructs have been developed for applications in diagnosis, imaging, and drug delivery. Nanoparticles as contrast agents enable conjugation with molecular markers which are essential for designing effective diagnostic and therapeutic strategies. Such investigations can also lead to a better understanding of disease mechanisms such as cancer-associated thrombosis which remains unpredictable with serious bleeding complications and high risk of death. Here we review the recent and current applications of engineered nanoparticles in diagnosis and therapeutic strategies, noting their toxicity in relation to specific markers as a target.