Group Of Uniform Materials Based On Organic Salts Research Articles

Recent Advances in Synthesis and Applications of Organic Ionic Saltsbased Sensor Arrays

Abstract: Sensor arrays contain a group of sensors, improve observations with new dimensions, provide better estimations, and additional parameters in comparison to the individual selective sensor. The array-based sensing technique provides good performance to respond to various gaseous or liquid analytes. Room temperature ionic liquids (RTILs) (melting point <25oC) and Group of uniform materials based on organic salts (GUMBOS) (melting point =25-250oC) are organic ionic salts, composed of an oppositely charged pair of bulky organic cations and bulky organic/inorganic anion and shows interesting tunable physicochemical properties. In this review article, we will discuss the sensing performance of ILs- and GUMBOS-based sensor arrays. ILs-based sensor arrays have been used in electrochemical gas sensing, solvent discrimination, colorimetric gas sensing, sensing of organic compounds, optoelectronic sensing of vapors and solutions, and vapour sensing through IL/QCM systems. GUMBOS-based sensor arrays have been employed in vapour sensing through the GUMBOS/QCM method, detection, and discrimination of proteins.

Studies of Protein Binding to Biomimetic Membranes Using a Group of Uniform Materials Based on Organic Salts Derived From 8-Anilino-1-naphthalenesulfonic Acid.

Tuning the 8-anilino-1-naphthalenesulfonic acid (ANS) structure usually requires harsh conditions and long reaction times, which can result in low yields. Herein, ANS was modified to form an ANS group of uniform materials based on organic salts (GUMBOS), prepared with simple metathesis reactions and distinct cations, namely tetrabutylammonium (N4444), tetrahexylammonium (N6666), and tetrabutylphosphonium (P4444). These ANS-based GUMBOS were investigated as fluorescent probes for membrane binding studies with four proteins having distinct physicochemical properties. Liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine were employed as membrane models as a result of their ability to mimic the structure and chemical composition of cell membranes. Changes in fluorescence intensity were used to monitor protein binding to liposomes, and adsorption data were fitted to a Freundlich-like isotherm. It was determined that [N4444][ANS] and [P4444][ANS] GUMBOS have enhanced optical properties and lipophilicity as compared to parent ANS. As a result, these two GUMBOS were selected for subsequent protein-membrane binding studies. Both [N4444][ANS] and [P4444][ANS] GUMBOS and parent ANS independently reached membrane saturation within the same concentration range. Furthermore, distinct fluorescence responses were observed upon the addition of proteins to each probe, which demonstrates the impact of properties such as lipophilicity on the binding process. The relative maintenance of binding cooperativity and maximum fluorescence intensity suggests that proteins compete with ANS-based probes for the same membrane binding sites. Finally, this GUMBOS-based approach is simple, rapid, and involves relatively small amounts of reagents, making it attractive for high-throughput purposes. These results presented herein can also provide relevant information for designing GUMBOS with ameliorated properties.

An ion metathesis strategy for overcoming therapeutic limitations of rose bengal

The therapeutic use of rose bengal (RB) has been limited by its anionic nature, high water solubility, and short half-life. Herein, RB was converted into a group of uniform materials based on organic salts (GUMBOS) via ion metathesis reactions to replace its sodium counterions with distinct cationic antiseptics (i.e., benzyldimethylhexadecylammonium, BZK; cetylpyridinium, C16Py; and chlorhexidine, CHX). The potential use of RB-based GUMBOS as antibacterial agents was investigated against a panel of Gram-positive and Gram-negative bacteria, namely Staphylococcus aureus (S. aureus), methicillin-resistant S. aureus (MRSA), Enterococcus faecalis (E. faecalis), Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). The micro-broth dilution method was used to determine the minimum inhibitory concentration (MIC) of synthesized GUMBOS as well as their parent compounds and unreacted stoichiometric mixtures. Hemolytic effects were further studied using human red blood cells. When compared to parent compounds and unreacted mixtures, GUMBOS showed equal or improved activity towards the non-resistant strain of S. aureus (i.e., DSM 2569) and E. faecalis. Additionally, [CHX][RB] was found to be active against E. coli with a MIC of 6.4–0.8 nmol mL−1, being 79 and 48 times more potent than RB and the corresponding unreacted mixture. The [CHX][RB] GUMBOS also showed the lowest hemolytic activity among all tested compounds and mixtures (percentage of hemolysis <5%). Overall, these results demonstrated that this ion metathesis strategy can improve the antibacterial activity of RB against Gram-positive bacteria and extend its spectrum of action towards E. coli, which could further contribute to safety improvements in multiple industries.

Fluoroquinolone-Based Organic Salts (GUMBOS) with Antibacterial Potential.

Antimicrobial resistance is a silent pandemic considered a public health concern worldwide. Strategic therapies are needed to replace antibacterials that are now ineffective. One approach entails the use of well-known antibacterials along with adjuvants that possess non-antibiotic properties but can extend the lifespan and enhance the effectiveness of the treatment, while also improving the suppression of resistance. In this regard, a group of uniform materials based on organic salts (GUMBOS) presents an alternative to this problem allowing the combination of antibacterials with adjuvants. Fluoroquinolones are a family of antibacterials used to treat respiratory and urinary tract infections with broad-spectrum activity. Ciprofloxacin and moxifloxacin-based GUMBOS were synthesized via anion exchange reactions with lithium and sodium salts. Structural characterization, thermal stability and octanol/water partition ratios were evaluated. The antibacterial profiles of most GUMBOS were comparable to their cationic counterparts when tested against Gram-positive S. aureus and Gram-negative E. coli, except for deoxycholate anion, which demonstrated the least effective antibacterial activity. Additionally, some GUMBOS were less cytotoxic to L929 fibroblast cells and non-hemolytic to red blood cells. Therefore, these agents exhibit promise as an alternative approach to combining drugs for treating infections caused by resistant bacteria.

Fabrication of a GUMBOS-based ratiometric organo nanosensor for selective and sensitive detection of perchlorate ions that works in 100% water

This work intends to develop sensitive and easily applicable ionic liquids (ILs)-based fluorimetric sensors for detecting the explosive perchlorate (ClO4-) anions in the presence of other hazards and interferents. We have designed and developed an IL-compromising pyrene butyrate anion-based fluorophoric group of uniform materials based on organic salts (GUMBOS), PBIL, from sodium pyrene butyrate and trihexyltetradecylphosphonium chloride (P66614Cl) by simple ion exchange mechanism. Using reprecipitation methods, pyrene-based water-suspended nano-GUMBOS, nPBIL, has been fabricated and characterized by numerous analytical methods. The fabricated nano-GUMBOS display bright cyan color photoluminescence due to the excimer-like emission confirmed from the color chromaticity diagram. Interestingly, due to the addition of ClO4- ions, there is a blue shift in the UV–visible absorption spectrum of the nPBIL solution with a simultaneous decrease in Mie-scattering. Consequently, there is a continuous decrease in the excimer-like emission of nPBIL with the synchronized increase in monomeric emission. We can conclude from both UV–visible absorption and emission spectra that the ClO4- ion displaces the anionic pyrene butyrate moiety of our nPBIL due to its high polarizability. The limit of detection (LOD) of the as-fabricated sensor is estimated to be 7.17 nM which is very much lower than the US Environmental Protection Agency (USEPA) predicted permeable level of perchlorate in drinking water (15 μgL−1). An efficient test kit has been fabricated and demonstrated for on-site detection of ClO4- ions in remote areas. This ion exchange-mediated substance release from such nano-GUMBOS systems is a distinctive and innovative way to design and develop efficient sensors for precisely detecting and quantifying ClO4- ions.

Protein discrimination using erythrosin B-based GUMBOS in combination with UV-Vis spectroscopy and chemometrics.

GUMBOS (Group of Uniform Materials Based on Organic Salts) have recently emerged as interesting materials for protein analysis due to their unique features and high tunability. In this regard, four novel erythrosin B (EB)-based GUMBOS were synthesized and their potential to discriminate among proteins with distinct properties (e.g., size, charge, and hydrophobicity) was assessed. These solid-phase materials were prepared using a single-step metathesis reaction between EB and various phosphonium and ammonium cations, namely tetrabutylphosphonium (P4444+), tributylhexadecylphosphonium (P44416+), tetrabutylammonium (N4444+), and benzyldimethylhexadecylammonium (BDHA+). Subsequently, the effect of pH (3.0, 4.5, and 6.0) and reaction time (5, 10, and 15min) on the discriminatory power of synthesized GUMBOS was evaluated. Absorption spectra resulting from the interaction between EB-based GUMBOS and proteins were analyzed using partial least squares discriminant analysis (PLSDA). Unlike time, the pH value was determined to have influence over GUMBOS discrimination potential. Correct protein assignments varied from 86.5% to 100.0%, and the best discriminatory results were observed for [P4444]2[EB] and [N4444]2[EB] at pH 6.0. Additionally, these two GUMBOS allowed discrimination of protein mixtures containing different ratios of albumin and myoglobin, which appeared as individualized clusters in the PLSDA scores plots. Overall, this study showcases EB-based GUMBOS as simple synthetic targets to provide a label-free, cost-effective, rapid, and successful approach for discrimination of single proteins and their mixtures.

Development of a Battery-Operated Handheld QCM Measurement Electronics

There continues to be major interest in detection and discrimination of volatile organic compounds (VOCs) because these compounds are pervasive in common environments, such as buildings, factories, and in households, among others. These VOCs can be detrimental to both human health and organisms in the environment. The quartz crystal microbalance (QCM) has become a popular analytical instrument to detect various VOCs [1]. However, most QCM studies are performed in a laboratory setting with cumbersome benchtop instruments. To utilize the QCM technique in a manner that permits researchers to be outside of a laboratory environment, such as VOCs detection on-site and point-of-care testing (POCT), it is important to develop a suitably portable QCM measurement system that maintains acceptable system performance, such as frequency resolution and measurement time, which requires low-power input [2, 3]. To fulfill this demand, we propose a QCM measurement electronic system that uses a phase-locked loop (PLL) circuit as a frequency-to-voltage converter and measures an output voltage level to calculate frequency shifts of the resonator. Our proposed system does not rely on the quality of a clock frequency, which is important in typical frequency counters to improve measurement performance. Instead, a common microcontroller is used to calculate frequency shift. In this work, a portable QCM system based on this strategy was developed, and its performance successfully characterized by measuring changes in system output voltage corresponding to input frequency changes. Temperature dependence of frequency changes was also investigated from 15 to 55 °C. With a resonance frequency of 5 MHz, the system showed a frequency resolution of 0.22 Hz, which is significantly less than a common frequency counter. For validation, we employed Ionic Liquids and a Group of Uniform Materials based on Organic Salts (GUMBOS) as chemosensitive coating materials for VOCs detection [4]. Measurement results of the frequency shift caused by VOCs from the developed system were comparable to those obtained from experiments with a commercial system (QSense Analyzer, Biolin Scientific), which demonstrates the feasibility of applying this electronic strategy for development of a portable QCM measurement system.

Development of an automated yeast-based spectrophotometric method for toxicity screening: Application to ionic liquids, GUMBOS, and deep eutectic solvents

Saccharomyces cerevisiae has been used as a eukaryotic model organism for studying the toxic effects of various compounds. In this context, an automated spectrophotometric method based on the enzymatic reduction of methylene blue dye to a colorless product by living yeast cells was implemented in a sequential injection analysis system. Loss of yeast viability/impaired metabolic activity was monitored by an increase in optical density at 664 nm. To prove the usefulness of this approach, the toxicity of ILs (ionic liquids), GUMBOS (group of uniform materials based on organic salts), and DESs (deep eutectic solvents) was examined. Differences obtained between IC50 values confirmed the impact of structural elements on each compounds’ toxicity. While DESs appeared to be less toxic than ILs, GUMBOS were found to be among the most toxic compounds to yeast cells and thus can be viewed as promising antimicrobial candidates. The automated methodology showed satisfactory repeatability and reproducibility (RSD < 9%), which is in good agreement with Green Chemistry principles. In fact, the method required consumption of only 40 μL of reagents and produced less than 2 mL of effluents per cycle. Thus, the developed assay can be used as an alternative tool for toxicity screening.

Octenidine/carbenicillin GUMBOS as potential treatment for oropharyngeal gonorrhoea.

Reducing Neisseria gonorrhoeae colonies in the oropharynx is a viable solution to minimize the transmission of this bacterium amongst individuals. A strategy involving the electrostatic interaction between a common antiseptic and a discontinued antibiotic (i.e. octenidine and carbenicillin) was evaluated as a potential treatment for gonorrhoea. Octenidine/carbenicillin is a novel group of uniform materials based on organic salts (GUMBOS) with inherent in vitro antibacterial activity that comes from its parent antiseptic and antibacterial ions, octenidine and carbenicillin, respectively. Antibacterial activities for octenidine dihydrochloride, disodium carbenicillin, octenidine/carbenicillin and stoichiometrically equivalent 1:1 octenidine dihydrochloride to disodium carbenicillin were assessed using the Kirby-Bauer disc diffusion assay for N. gonorrhoeae (ATCC 49226) and three clinical isolates. Predictive permeability using the Parallel Artificial Membrane Permeability Assay and cytotoxicity against HeLa cells was also evaluated. Additive in vitro antibacterial activities against N. gonorrhoeae were observed in this study, which suggests octenidine/carbenicillin could be a useful agent in reducing N. gonorrhoeae transmission and minimizing gonorrhoea infections. Octenidine/carbenicillin also exhibited bioequivalence to azithromycin and doxycycline, two currently prescribed antibiotics. Likewise, octenidine/carbenicillin had improved predicted permeability compared with octenidine dihydrochloride. Antimicrobial GUMBOS synthesized in this study could be used as an adjunctive treatment approach to current drug therapies for oropharyngeal gonorrhoea infection control and prevention.

Protein Discrimination Using a Fluorescence-Based Sensor Array of Thiacarbocyanine-GUMBOS.

Sensitive and selective detection of proteins from complex samples has gained substantial interest within the scientific community. Early and precise detection of key proteins plays an important role in potential clinical diagnosis, treatment of different diseases, and proteomic research. In the study reported here, six different compounds belonging to a group of uniform materials based on organic salts (GUMBOS) have been synthesized using three thiacarbocyanine (TC) dyes and employed as fluorescent sensors. Fluorescence properties of micro- and nanoaggregates of these TC-based GUMBOS formed in phosphate buffer solutions are studied in the absence and presence of seven proteins. Fluorescence response patterns of these TC-based GUMBOS were analyzed by linear discriminant analysis (LDA). The constructed LDA model allowed discrimination of these seven proteins at various concentrations with 100% accuracy. The sensing and discrimination abilities of these TC-based GUMBOS were further evaluated in mixtures of two major proteins, i.e., human serum albumin and hemoglobin. Fluorescence response patterns of these mixtures were analyzed by LDA. This model allowed discrimination of various mixtures with 100% accuracy. Moreover, spiked urine samples were prepared and the responses of these sensors were collected and analyzed by LDA. Remarkably, discrimination of these seven proteins was also achieved with 100% accuracy.

Comparison of Chemotherapeutic Activities of Rhodamine-Based GUMBOS and NanoGUMBOS.

Rhodamine derivatives have been widely investigated for their mitochondrial targeting and chemotherapeutic properties that result from their lipophilic cationic structures. In previous research, we have found that conversion of Rhodamine 6G into nanoGUMBOS, i.e., nanomaterials derived from a group of uniform materials based on organic salts (GUMBOS), led to selective chemotherapeutic toxicity for cancer cells over normal cells. Herein, we investigate the chemotherapeutic activity of GUMBOS derived from four different rhodamine derivatives, two bearing an ester group, i.e., Rhodamine 123 (R123) and SNAFR-5, and two bearing a carboxylic acid group, i.e., rhodamine 110 (R110) and rhodamine B (RB). In this study, we evaluate (1) relative hydrophobicity via octanol–water partition coefficients, (2) cytotoxicity, and (3) cellular uptake in order to evaluate possible structure–activity relationships between these different compounds. Intriguingly, we found that while GUMBOS derived from R123 and SNAFR-5 formed nanoGUMBOS in aqueous medium, no distinct nanoparticles are observed for RB and R110 GUMBOS. Further investigation revealed that the relatively high water solubility of R110 and RB GUMBOS hinders nanoparticle formation. Subsequently, while R123 and SNAFR-5 displayed selective chemotherapeutic toxicity similar to that of previously investigated R6G nanoGUMBOS, the R110 and RB GUMBOS were lacking in this property. Additionally, the chemotherapeutic toxicities of R123 and SNAFR-5 nanoGUMBOS were also significantly greater than R110 and RB GUMBOS. Observed results were consistent with decreased cellular uptake of R110 and RB as compared to R123 and SNAFR-5 compounds. Moreover, these results are also consistent with previous observations that suggest that nanoparticle formation is critical to the observed selective chemotherapeutic properties as well as the chemotherapeutic efficacy of rhodamine nanoGUMBOS.

Tumor-Targeting NIRF NanoGUMBOS with Cyclodextrin-Enhanced Chemo/Photothermal Antitumor Activities.

The near-infrared fluorescent (NIRF) dye, IR780, is recognized as a promising theranostic agent and has been widely investigated for imaging, chemotherapeutic, and phototherapeutic applications. However, its poor photostability and nonselective toxicities toward both cancer and normal cells limit its biological applications. Herein, we introduce the use of GUMBOS (a group of uniform materials based on organic salts) developed through counter-anion exchange with IR780 and subsequent nanomaterials (nanoGUMBOS) formed by complexation with cyclodextrin (CD) for enhanced chemo/photothermal therapy. Such CD-based nanoGUMBOS display improved aqueous stability, photostability, and photothermal effects relative to traditional IR780. The examination of in vitro cytotoxicity reveals that CD-based nanoGUMBOS are selectively toxic toward cancer cells and exhibit synergistically enhanced cytotoxicity toward cancer cells upon NIR laser irradiation. Additionally, in vivo NIRF imaging demonstrated selective accumulation of these nanoGUMBOS within the tumor site, indicating tumor-targeting properties. Further in vivo therapeutic study of these CD-based nanoGUMBOS suggests excellent chemo/photothermal antitumor effects. Using these studies, we herein demonstrate a promising strategy, via conversion of IR780 into nanoGUMBOS, that can be used for improved theranostic cancer treatment.

Fluorescence-Based Ratiometric Nanosensor for Selective Imaging of Cancer Cells

Herein, we report the synthesis and characterization of a nanosensor developed from a group of uniform materials based on organic salts (GUMBOS). This sensor is composed of three ionic species, nam...

Endocytic Selective Toxicity of Rhodamine 6G nanoGUMBOS in Breast Cancer Cells.

Herein, we report on the role of endocytosis in the selective chemotherpeutic toxicity of rhodamine 6G (R6G) based nanomaterials, i.e., nanoGUMBOS, that are derived from a group of uniform materials based on organic salts (GUMBOS). Evaluation of cellular uptake in the presence and absence of endocytosis inhibitors suggests nanoGUMBOS internalization via clathrin-mediated endocytosis in cancer cells and reveals lack of endocytic internalization in normal cells. Results from characterization of these nanomaterials suggest that endocytic internalization in cancer cells leads to nanoGUMBOS dissociation within the endosomal environment. This ultimately results in selective cytotoxicity of the nanoGUMBOS for cancer cells with no toxicity toward normal cells under examined conditions. Following examination of the selectivity mechanism, in vivo investigations were performed to examine potential therapeutic properties of these nanoparticles. Remarkably, nanoGUMBOS treatment using a mouse xenograft model reduced the tumor volume by 50% suggesting retention of in vitro therapeutic properties in vivo. These results corroborate the selective behavior of nanoGUMBOS and demonstrate their in vivo therapeutic effects, providing further insight into the possible use of these nanomaterials as potential chemotherapeutic agents.

Organic Salts: Tunable Materials for Analytical Applications

Event Abstract Back to Event Organic Salts: Tunable Materials for Analytical Applications Isiah M. Warner1* and Mingyan Cong1 1 Louisiana State University, United States My research group has been exploring the scientific applications of room-temperature ionic liquids (RTILs) for several years. More recently, we have extended the range of these materials to include applications of similar solid phase materials, i.e. organic salts with melting points of solid phase ionic liquids (25 °C to 100 °C) up to organic salts with melting points of 250 °C. To contrast these new materials with RTILs, we have created the acronym, GUMBOS (Group of Uniform Materials Based on Organic Salts). These GUMBOS have the tunable properties frequently associated with RTILs, including tunable solubility, melting point, viscosity, thermal stability, hydrophobicity, and functionality. Thus, when taken in aggregate, GUMBOS allow production of solid phase materials which have a wide range of biomedical and other scientific applications. Our GUMBOS have led to applications in many areas including sensors, cancer therapy, novel approach to antibiotics, and production of tunable nanomaterials (nanoGUMBOS). In regard to nanomaterials (nanoGUMBOS), we believe that our methodology represents an extremely useful approach to production of tunable nanomaterials since our materials are designed and assembled for specific uses (task specific), rather than adapted for use as is done for many nanomaterials. Selected applications of ionic liquids and GUMBOS, including sensor applications and cancer therapy, will be highlighted in this talk. Particular emphasis will be placed on a possible new development for selective cancer therapy. Acknowledgements This material is based upon work supported by the National Science Foundation under Grant Nos. CHE-1307611 and CHE-1508726. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Keywords: GUMBOS, NanoGUMBOS, Sensors, Hemoglobin, reactive oxygen species Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Oral Presentation Topic: Analytical Chemsitry Citation: Warner IM and Cong M (2019). Organic Salts: Tunable Materials for Analytical Applications. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00016 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 08 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Isiah M Warner, Louisiana State University, Baton Rouge, United States, iwarner@lsu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Isiah M Warner Mingyan Cong Google Isiah M Warner Mingyan Cong Google Scholar Isiah M Warner Mingyan Cong PubMed Isiah M Warner Mingyan Cong Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Enhanced chemotherapeutic toxicity of cyclodextrin templated size-tunable rhodamine 6G nanoGUMBOS.

Nanodrugs have been widely investigated for combating the large number of side effects associated with conventional therapeutics. Several investigations of such nanomedicines have demonstrated the profound role of nanoparticle size in therapeutic efficacy. Herein, we report the role of cyclodextrin (CD)-templating on the size and therapeutic properties of rhodamine 6G (R6G) nanoGUMBOS, i.e. nanomaterials derived from a Group of Uniform Materials Based on Organic Salts (GUMBOS). In these studies, templating of nanoGUMBOS using 2-hydroxypropyl-alpha (2-HP-α), 2-hydroxypropyl beta (2-HP-β), and gamma (γ) cyclodextrin (CD) led to a significant reduction in size and enhanced uniformity as indicated by transmission electron microscopy (TEM) images. In addition, CD-templated nanoGUMBOS remarkably displayed a three to four fold enhancement in toxicity towards cancer cells as compared to nanoGUMBOS without CD-templates, suggesting a significant improvement in therapeutic efficacy. Correlation between size and toxicity suggests that CD-templated nanoparticles of ∼70 to 80 nm produced optimal toxicity. Even more interesting, all investigated nanoGUMBOS displayed no toxicity toward normal cells under examined conditions. Moreover, these nanoGUMBOS display comparable chemotherapeutic toxicity to the parent dye, [R6G][Cl], while also eliminating toxicity towards normal cells, indicating their strong chemotherapeutic potential. The studies outlined here provide further insight into an approach that may be employed for rapid synthesis of size tunable nanodrugs for enhanced chemotherapeutic efficacy.

Ratiometric fluorescence detection of hydroxyl radical using cyanine-based binary nanoGUMBOS

Overproduction of reactive oxygen species (ROS) results in oxidative stress, which is closely associated with pathogenesis of many diseases. Visualized detection of ROS in situ enables deeper insight into the mechanisms that underlie such pathological and physiological processes. Among reactive species, selective detection of hydroxyl radical is the most challenging, due to high aggression and short life time of this specie. In this regard, we have developed a sensitive and selective ratiometric fluorescence nanoprobe for detection of hydroxyl radical. This probe is based on use of GUMBOS (a Group of Uniform Materials Based on Organic Salts) that are derived from 1,1′-diethyl-2,2′-cyanine iodide and 1,1′-diethyl-2,2′-carbocyanine iodide. Each GUMBOS exhibit different reactivity towards reactive species. Without any chemical linkage, these two GUMBOS were combined into a single nanomaterial to produce a ratiometric fluorescent sensing profile through Förster resonance energy transfer. This cyanine-based ratiometric nanoprobe exhibited high selectivity for the hydroxyl radical in comparison to other ROS, including superoxide anion, singlet oxygen, hydrogen peroxide, and peroxynitrite. Furthermore, detection of hydroxyl radical was successfully demonstrated by use of these binary nanoGUMBOS in vitro using hormone-independent human breast adenocarcinoma cells (MDA-MB-231).

Synthesis and Characterization of Porphyrin-Based GUMBOS and NanoGUMBOS as Improved Photosensitizers

Porphyrin-based GUMBOS and nanoGUMBOS were synthesized for potential application as improved photosensitizing materials. In this study, porphyrin dyes [meso-tetra(4-carboxyphenyl)porphine (TCPP) and zinc(II) meso-tetra(4-carboxyphenyl)porphine (Zn-TCPP)] were selected as anions, and trihexyltetradecylphosphonium (P66614) was employed as a cation. The resulting [P66614]4[TCPP] and [P66614]4[Zn-TCPP] GUMBOS (group of uniform materials based on organic salts) provided high photostability and excellent thermal stability for these compounds. NanoGUMBOS, i.e., nanomaterials derived from GUMBOS, were synthesized using reprecipitation and ion association methods. The surface charges of these nanoparticles were tuned from positive to negative through use of an ion association synthetic method without the need for additives or stabilizers. When compared to the parent dyes, nanoGUMBOS exhibited excellent photodynamic properties for potential applications as photosensitizers. Evaluation of the electrochemical propert...

Improving energy relay dyes for dye-sensitized solar cells by use of a group of uniform materials based on organic salts (GUMBOS)

Energy relay dyes based on GUMBOS displayed improved characteristics in comparison to respective parent dyes including solubility and solar efficiency.

Anomalous Size-Dependent Excited-State Relaxation Dynamics of NanoGUMBOS

The synthesis, characterization, and ultrafast spectroscopy of size-selected nanospheres of ruthenium bipyridine–bis(pentafluoroethylsulfonyl)imide ([Ru(bipy)3][BETI]2) in water are reported. These studies represent the first experimental evidence of phonons with nanosecond lifetimes in organometallic nanomaterials. Thermally stable, crystalline nanoparticles of [Ru(bipy)3][BETI]2 are derived from a group of uniform materials based on organic salts (GUMBOS). Excited-state relaxation dynamics are studied using pump–probe time-resolved transient absorption spectroscopy, and the results are compared to corresponding measurements of aqueous Ru(bipy)3Cl2. The nanoGUMBOS show spectral shifts and size-dependent relaxation dynamics for nanoparticle diameters varying from 20 to 100 nm, characterized by excited-state decay dynamics similar to those of the precursor dye at higher pump pulse energies with an additional pathway attributed to intermolecular energy transfer, where all lifetimes increase with increasing ...