Tunable cytotoxicity of rhodamine 6G via anion variations

Antibacterial, anti-inflammatory and wet-adhesive poly(ionic liquid)-based oral patch for the treatment of oral ulcers with bacterial infection

Oral aphthous ulcers are a common inflammatory efflorescence of oral mucosa, presenting as inflammation and oral mucosal damage and manifesting as pain. The moist and highly dynamic environment of the oral cavity makes the local treatment of oral aphthous ulcers challenging. Herein, a poly(ionic liquid)-based diclofenac sodium (DS)-loaded (PIL-DS) buccal tissue adhesive patch fabricated with intrinsically antimicrobial, highly wet environment adhesive properties and anti-inflammatory activities to treat oral aphthous ulcers was developed. The PIL-DS patch was prepared via polymerization of a catechol-containing ionic liquid, acrylic acid, and butyl acrylate, followed by anion exchange with DS-. The PIL-DS can adhere to wet tissues, including mucosa muscles and organs, and efficiently deliver the carried DS- at wound sites, exerting remarkable synergistic antimicrobial (bacteria and fungi) properties. Accordingly, the PIL-DS elicited dual therapeutic effects on oral aphthous ulcers with Staphylococcus aureus infection through antibacterial and anti-inflammatory activities, significantly accelerating oral aphthous ulcer healing as an oral mucosa patch. The results indicated that the PIL-DS patch, with inherently antimicrobial and wet adhesion properties, is promising for treating oral aphthous ulcers in clinical practice. STATEMENT OF SIGNIFICANCE: Oral aphthous ulcers are a common oral mucosal disease, which could lead to bacterial infection and inflammation in severe cases, especially for people with large ulcers or low immunity. However, moist oral mucosa and highly dynamic oral environment make it challenging to maintain therapeutic agents and physical barriers at the wound surface. Therefore, an innovative drug carrier with wet adhesion is urgently needed. Herein, a poly(ionic liquid)-based diclofenac sodium (DS)-loaded (PIL-DS) buccal tissue adhesive patch was developed to treat oral aphthous ulcers showing intrinsically antimicrobial and highly wet environment adhesive properties due to the presence of catechol-containing ionic liquid monomer. Additionally, the PIL-DS showed significantly therapeutic effects on oral aphthous ulcers with S. aureus infection through antibacterial and anti-inflammatory activities. We expect that our work can provide inspiration for the development of treatment for microbially infected oral ulcers.

Anticancer Activity of Nano-formulated Orlistat-Dopamine Conjugates Through Self-Assembly

Orlistat, an FDA-approved fatty acid inhibitor for obesity treatment, demonstrates certain low and greatly varied anticancer abilities. In a previous study, we revealed a synergistic effect between orlistat and dopamine in cancer treatment. Here, orlistat-dopamine conjugates (ODCs) with defined chemical structures were synthesized. The ODC by design underwent polymerization and self-assembly in the presence of oxygen to form nano-sized particles (Nano-ODCs) spontaneously. The resulted Nano-ODCs of partial crystalline structures demonstrated good water dispersion to form stable Nano-ODC suspensions. Because of the bioadhesive property of the catechol moieties, once administered, Nano-ODCs were quickly accumulated on cell surfaces and efficiently uptaken by cancer cells. In the cytoplasm, Nano-ODC experienced biphasic dissolution followed by spontaneous hydrolysis to release intact orlistat and dopamine. Besides elevated levels of intracellular reactive oxygen species (ROS), the co-localized dopamine also induced mitochondrial dysfunctions through monoamine oxidases (MAOs)-catalyzed dopamine oxidation. The strong synergistic effects between orlistat and dopamine determined a good cytotoxicity activity and a unique cell lysis mechanism, explaining the distinguished activity of Nano-ODC to drug-sensitive and -resistant cancer cells. This new technology-enabled orlistat repurposing will contribute to overcoming drug resistance and the improvement of cancer chemotherapy.

A CO2-Responsive Imidazole-Functionalized Fluorescent Material Mediates Cancer Chemotherapy

We present a breakthrough in the synthesis and development of functional gas-responsive materials as highly potent anticancer agents suitable for applications in cancer treatment. Herein, we successfully synthesised a stimuli-responsive multifunctional material (I-R6G) consisting of a carbon dioxide (CO₂)-sensitive imidazole moiety and spirolactam-containing conjugated rhodamine 6G (R6G) molecule. The resulting I-R6G is highly hydrophobic and non- or weakly fluorescent. Simple CO₂ bubbling treatment induces hydrophobic I-R6G to completely dissolve in water and subsequently form self-assembled nanoparticles, which exhibit unique optical absorption and fluorescence behaviours in water and extremely low haemolytic ability against sheep red blood cells. Reversibility testing indicated that I-R6G undergoes reversible CO₂/nitrogen (N₂)-dependent stimulation in water, as its structural and physical properties can be reversibly and stably switched by alternating cycles of CO₂ and N₂ bubbling. Importantly, in vitro cellular assays clearly demonstrated that the CO₂-protonated imidazole moiety promotes rapid internalisation of CO₂-treated I-R6G into cancer cells, which subsequently induces massive levels of necrotic cell death. In contrast, CO₂-treated I-R6G was not internalised and did not affect the viability of normal cells. Therefore, this newly created system may provide an innovative and efficient route to remarkably improve the selectivity, safety and efficacy of cancer treatment.

Efficient Anion-Exchange Membranes with Anti-Scaling Properties Obtained by Surface Modification of Commercial Membranes Using a Polyquaternium-22

Anion-exchange membranes modified with a polyquaternium-22 (PQ-22) polymer were studied for their use in electrodialysis. The use of PQ-22 for modification makes it possible to "replace" weakly basic amino groups on the membrane surface with quaternary amino groups. It was found that the content of quaternary amino groups in PQ-22 is higher than the content of carboxyl groups, which is the reason for the effectiveness of this polymer even when modifying Ralex AHM-PES membranes that initially contain only quaternary amino groups. In the case of membranes containing weakly basic amino groups, the PQ-22 polymer modification efficiency is even higher. The surface charge of the modified MA-41P membrane increased, while the limiting current density on the current-voltage curves increased by more than 1.5 times and the plateau length decreased by 2.5 times. These and other characteristics indicate that the rate of water splitting decreased and the electroconvective mixing at the membrane surface intensified, which was confirmed by direct visualization of vortex structures. Increasing the surface charge of the commercial MA-41P anion-exchange membrane, reducing the rate of water splitting, and enhancing electroconvection leads to mitigated scaling on its surface during electrodialysis.

A Multifunctional Conjugated Polymer Developed as an Efficient System for Differentiation of SH-SY5Y Tumour Cells

Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.

Enhanced photothermal heating and combination therapy of NIR dye via conversion to self-assembled ionic nanomaterials

Combination nanodrugs are promising therapeutic agents for cancer treatment. However, they often require the use of complex nanovehicles for transportation into the tumor site. Herein, a new class of carrier-free ionic nanomaterials (INMs) is presented, which are self-assembled by the drug molecules themselves. In this regard, a photothermal therapy (PTT) mechanism is combined with a chemotherapy (chemo) mechanism using ionic liquid chemistry to develop a combination drug to deliver multiple cytotoxic mechanisms simultaneously. Nanodrugs were developed from an ionic material-based chemo-PTT combination drug by using a simple reprecipitation method. Detailed examination of the photophysical properties (absorption, fluorescence emission, quantum yield, radiative and non-radiative rate) of the INMs revealed significant spectral changes which are directly related to their therapeutic effect. The reactive oxygen species quantum yield and the light to heat conversion efficiency of the photothermal agents were shown to be enhanced in combination nanomedicines as compared to their respective parent compounds. The ionic nanodrugs exhibited an improved dark and light cytotoxicity in vitro as compared to either the chemotherapeutic or photothermal parent compounds individually, due to a synergistic effect of the combined therapies, improved photophysical properties and their nanoparticles' morphology that enhanced the cellular uptake of the drugs. This study presents a general framework for the development of carrier-free dual-mechanism nanotherapeutics.

N-Cyanorhodamines: cell-permeant, photostable and bathochromically shifted analogues of fluoresceins

Fluorescein and its analogues have found only limited use in biological imaging because of the poor photostability and cell membrane impermeability of their O-unprotected forms. Herein, we report rationally designed N-cyanorhodamines as orange- to red-emitting, photostable and cell-permeant fluorescent labels negatively charged at physiological pH values and thus devoid of off-targeting artifacts often observed for cationic fluorophores. In combination with well-established fluorescent labels, self-labelling protein (HaloTag, SNAP-tag) ligands derived from N-cyanorhodamines permit up to four-colour confocal and super-resolution STED imaging in living cells.

N-Cyanorhodamines – photostable, cell-permeant analogues of fluoresceins – provide fast labelling kinetics with the HaloTag protein and background-free images in multicolour super-resolution microscopy.

Influence of Electroconvection on Chronopotentiograms of an Anion-Exchange Membrane in Solutions of Weak Polybasic Acid Salts

Visualization of electroconvective (EC) vortices at the undulated surface of an AMX anion-exchange membrane (Astom, Osaka, Japan) was carried out in parallel with the measurement of chronopotentiograms. Weak polybasic acid salts, including 0.02 M solutions of tartaric (NaHT), phosphoric (NaH₂PO₄), and citric (NaH₂Cit) acids salts, and NaCl were investigated. It was shown that, for a given current density normalized to the theoretical limiting current calculated by the Leveque equation (i/i_lim^theor), EC vortex zone thickness, d_EC, decreases in the order NaCl > NaHT > NaH₂PO₄ > NaH₂Cit. This order is inverse to the increase in the intensity of proton generation in the membrane systems under study. The higher the intensity of proton generation, the lower the electroconvection. This is due to the fact that protons released into the depleted solution reduce the space charge density, which is the driver of EC. In all studied systems, a region in chronopotentiograms between the rapid growth of the potential drop and the attainment of its stationary values corresponds to the appearance of EC vortex clusters. The amplitude of the potential drop oscillations in the chronopotentiograms is proportional to the size of the observed vortex clusters.

Complementary Nucleobase Interactions Drive Co-Assembly of Drugs and Nanocarriers for Selective Cancer Chemotherapy

A new concept in cooperative adenine-uracil (A-U) hydrogen bonding interactions between anticancer drugs and nanocarrier complexes was successfully demonstrated by invoking the co-assembly of water soluble, uracil end-capped polyethylene glycol polymer (BU-PEG) upon association with the hydrophobic drug adenine-modified rhodamine (A-R6G). This concept holds promise as a smart and versatile drug delivery system for the achievement of targeted, more efficient cancer chemotherapy. Due to A-U base pairing between BU-PEG and A-R6G, BU-PEG has high tendency to interact with A-R6G, which leads to the formation of self-assembled A-R6G/BU-PEG nanogels in aqueous solution. The resulting nanogels exhibit a number of unique physical properties, including extremely high A-R6G-loading capacity, well-controlled, pH-triggered A-R6G release behavior, and excellent structural stability in biological media. Importantly, a series of in vitro cellular experiments clearly demonstrated that A-R6G/BU-PEG nanogels improved the selective uptake of A-R6G by cancer cells via endocytosis and promoted the intracellular release of A-R6G to subsequently induce apoptotic cell death, while control rhodamine/BU-PEG nanogels did not exert selective toxicity in cancer or normal cell lines. Overall, these results indicate that cooperative A-U base pairing within nanogels is a critical factor that improves selective drug uptake and effectively promotes apoptotic programmed cell death in cancer cells.

Synthesis, Characterization, and Biological Activity of Water-Soluble, Dual Anionic and Cationic Ruthenium-Arene Complexes Bearing Imidazol(in)ium-2-dithiocarboxylate Ligands

An efficient synthetic protocol was devised for the preparation of five cationic ruthenium-arene complexes bearing imidazol(in)ium-2-dithiocarboxylate ligands from the [RuCl₂(p-cymene)]₂ dimer and 2 equiv of an NHC·CS₂ zwitterion. The reactions proceeded cleanly and swiftly in dichloromethane at room temperature to afford the expected [RuCl(p-cymene)(S₂C·NHC)]Cl products in quantitative yields. When the [RuCl₂(p-cymene)]₂ dimer was reacted with only 1 equiv of a dithiolate betaine under the same experimental conditions, a set of five bimetallic compounds with the generic formula [RuCl(p-cymene)(S₂C·NHC)][RuCl₃(p-cymene)] was obtained in quantitative yields. These novel, dual anionic and cationic ruthenium-arene complexes were fully characterized by various analytical techniques. NMR titrations showed that the chelation of the dithiocarboxylate ligands to afford [RuCl(p-cymene)(S₂C·NHC)]⁺ cations was quantitative and irreversible. Conversely, the formation of the [RuCl₃(p-cymene)]^- anion was limited by an equilibrium, and this species readily dissociated into Cl^- anions and the [RuCl₂(p-cymene)]₂ dimer. The position of the equilibrium was strongly influenced by the nature of the solvent and was rather insensitive to the temperature. Two monometallic and two bimetallic complexes cocrystallized with water, and their molecular structures were solved by X-ray diffraction analysis. Crystallography revealed the existence of strong interactions between the azolium ring protons of the cationic complexes and neighboring donor groups from the anions or the solvent. The various compounds under investigation were highly soluble in water. They were all strongly cytotoxic against K562 cancer cells. Furthermore, with a selectivity index of 32.1, the [RuCl(p-cymene)(S₂C·SIDip)]Cl complex remarkably targeted the erythroleukemic cells vs mouse splenocytes.

Potential role of nanobubbles in dynamically modulating the structure and stability of anammox granular sludge within biological nitrogen removal process

The generation of visible macrobubbles considerably affects the structure and function of anammox granules in the anammox granular sludge (AnGS) system. However, the existence of nanobubbles (NBs) and their role in maintaining the AnGS structure and stability are unclear because of the complexity of the system and lack of effective analytical methods. In this study, methods for NB analysis and assessment of their effects were developed to investigate the formation and characteristics of NBs in an AnGS system and the effects of NBs on the properties and function of AnGS. The results indicated that dissolved gas supersaturation caused by AnGS generated NBs of 2.75 × 10⁸ bubbles/mL inside an AnGS reactor after running for 300 min at 30 °C. The increasing absolute value of the zeta potential of NBs with time indicated that the NBs in the AnGS system were gradually stable. The size of the stable NBs ranged from 150 nm to 400 nm. NB formation also increased the space and pressure between cells, leading to the breakage of the cell cluster and causing structural changes in granules. Changes in the local granular microstructure caused by NBs were favorable for the porous structure of granules to avoid granular disintegration and flotation caused by the excessive secretion of extracellular polymeric substances blocking gas channels. The formation and stability of NBs penetrating the cell clusters played a crucial role in the formation and stability of nanopores around or inside the cell clusters, further providing a basis for the formation of high-porosity structures and efficient mass transfer of AnGS.

Bulky Barbiturates as Non-Toxic Ionic Dye Insulators for Enhanced Emission in Polymeric Nanoparticles

Bulky hydrophobic counterions (weakly coordinating anions) can insulate ionic dyes against aggregation-caused quenching (ACQ) and enable preparation of highly fluorescent dye-loaded nanoparticles (NPs) for bioimaging, biosensing and light harvesting. Here, we introduce a family of hydrophobic anions based on fluorinated C-acyl barbiturates with delocalized negative charge and bulky non-polar groups. Similarly to fluorinated tetraphenylborates, these barbiturates prevent ACQ of cationic dye alkyl rhodamine B inside polymer NPs made of biodegradable poly(lactic-co-glycolic acid) (PLGA). Their efficiency to prevent ACQ increases for analogues with higher acidity and bulkiness. Their structure controls dye-dye communication, yielding bright NPs with on/off switching or stable emission. They enhance dye encapsulation inside NPs, allowing intracellular imaging without dye leakage. Compared to fluorinated tetraphenylborates known as cytotoxic transmembrane ion transporters, the barbiturates display a significantly lower cytotoxicity. These chemically available and versatile barbiturate derivatives are promising counterion scaffolds for preparation of bright non-toxic fluorescent nanomaterials.

Current Advances in Photoactive Agents for Cancer Imaging and Therapy

Photoactive agents are promising complements for both early diagnosis and targeted treatment of cancer. The dual combination of diagnostics and therapeutics is known as theranostics. Photoactive theranostic agents are activated by a specific wavelength of light and emit another wavelength, which can be detected for imaging tumors, used to generate reactive oxygen species for ablating tumors, or both. Photodynamic therapy (PDT) combines photosensitizer (PS) accumulation and site-directed light irradiation for simultaneous imaging diagnostics and spatially targeted therapy. Although utilized since the early 1900s, advances in the fields of cancer biology, materials science, and nanomedicine have expanded photoactive agents to modern medical treatments. In this review we summarize the origins of PDT and the subsequent generations of PSs and analyze seminal research contributions that have provided insight into rational PS design, such as photophysics, modes of cell death, tumor-targeting mechanisms, and light dosing regimens. We highlight optimizable parameters that, with further exploration, can expand clinical applications of photoactive agents to revolutionize cancer diagnostics and treatment.

Enhanced antibacterial activity of a novel biocompatible triarylmethane based ionic liquid-graphene oxide nanocomposite

Biofilm formation on medical implants and devices has been a severe concern that results in their impaired performance and life-threatening complications. Thus, development of novel functional coatings for infection prone surfaces with biofilm inhibiting characteristics is of prime significance considering the rapid emergence of multidrug resistant bacteria. Herein we present a novel nanocomposite derived from Graphene Oxide (GO) and a newly developed functional Ionic liquid (IL) obtained through a metathesis reaction between a triarylmethane dye hexamethyl pararosaniline chloride or crystal violet (CV) and sodium dodeceyl sulfate (SDS) to yield [CV][DS] (hexamethyl pararosaniline dodecyl sulfate). This highly biocompatible [CV][DS]-GO nanocomposite exhibit more than four times improved antibacterial activity in comparison to bare GO against both gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). As suggested by XRD, FTIR and UV absorption and SEM results improved activity of [CV][DS]-GO nanocomposite is ascribed to the synergistic effect of reduced nanocomposite sheet thickness, enhanced amphiphilicity imparted by dodecylsulfate (DS), exposed active ArN⁺ groups of CV and some inherent functionalities of GO. This is also complemented by the ruptured and diffused S. aureus cell walls as observed in bacterial SEM result. In contrast, the nanocomposites of the precursors with GO do not demonstrate any significant antibacterial effect. Coatings developed using GO upon infestation with E. coli revealed significant biofilm formation after 48 and 72 h of incubation while [CV][DS]-GO coated surface demonstrated no colony growth under similar circumstances. Thus, [CV][DS]-GO nanocomposite coatings exhibit excellent resistance to bacterial growth even up to 72 h incubation signifying its bactericidal effect. Therefore, the developed nanocomposite may be considered as one of the improved antibacterial wash resistant coating material for biomedical devices and surfaces susceptible to to biofilm formation.

Fabrication of a GUMBOS-based acid-base indicator: smart probe for sensing acids and bases in any solvent

This report outlines the synthesis of an ionic liquid-based pH-responsive indicator to sense acids or bases in non-polar as well as polar solvents. Herein, we have assembled a new ionic liquid (IL) comprised of a group of uniform materials based on organic salts (GUMBOS) by attaching a quaternary phosphonium ionic liquid with a very common acid-base indicator, methyl orange, via simple ion-exchange reaction. This integrated IL-based indicator is highly soluble in less polar solvents and exhibits good sensitivity toward the presence of acids/bases in those media. Furthermore, this indicator has been exploited in determining the dissociation constants of several acids in non-aqueous aprotic solvents by overlapping indicator method and hence this report provides essential information toward the understanding of many fundamental chemical reactions. This report has further scope for the synthesis of novel aqueous suspended nanomaterials, i.e., the nanoparticles derived from GUMBOS (nanoGUMBOS) by a simple flash nano-precipitation method. The nanomaterial has been well characterized by different spectroscopic and microscopic studies. The obtained nanoparticles also exhibit substantial pH-responsive behaviors in aqueous medium and show better susceptibility as compared to the free organic indicator. Thus, this report explores detailed studies on the IL-based indicator in sensing the acidity/basicity of various media.

Analysis of Ion Pairing in Solid State and Solution in p-Cymene Ruthenium Complexes

The importance of ion pairing in different fields of chemistry is widely recognized. In this work, we have synthesized a set of cationic p-cymene ruthenium complexes of general formula [(p-cym)Ru(L')(κ²-O^N-L)]X (p-cym = p-cymene; L' = N-methylimidazole (MeIm), N-ethylpiperidylimidazole (EpipIm), 1,3,5-triaza-7-phosphaadamantane (PTA); L = 2-(1H-benzimidazol-2-yl)phenolato (L1), 2-(1,3-benzothiazol-2-yl)phenolato (L2); X = Cl^-, BF₄^-, OTf^-, BPh₄^-). X-ray diffraction studies on selected complexes revealed relatively strong anion-cation interactions in the solid state mainly based on N-H···X (X = Cl, F, O) and C-H···π interactions, also observed in the DFT-modeled complexes in the gas phase. Moreover, NMR studies showed that they exist as intimate ion pairs in solution and, remarkably, as head-to-tail quadruples in the particular case of the cation [(p-cym)Ru(MeIm)(κ²- O^N-L1)]⁺ ([1]⁺) with Cl^- and BPh₄^- as counteranions. Furthermore, a value of ΔG = -2.9 kcal mol^-1 at 299 K has been estimated for the equilibrium {[1]BPh₄···[1]BPh₄} ⇆ 2{[1]⁺···BPh₄^-} in concentrated CDCl₃ solutions. In addition, preliminary studies concerning the cytotoxic properties against HeLa cell lines of the derivatives suggested a positive effect derived from the presence of the lipophilic BPh₄^- anion and also from the NH group of the benzimidazolyl fragment.

Active pharmaceutical ingredient poly(ionic liquid)-based microneedles for the treatment of skin acne infection

As an inflammatory skin disease of pilosebaceous follicles, Propionibacterium acnes (P. acnes) can aggravate local inflammatory responses and forms acne lesions. However, due to the skin barrier, various transdermal measures other than antibiotic creams are necessary. Microneedle (MN) patches are emerging platforms for the transdermal delivery of various therapeutics since it can effectively create transport pathways in the epidermis. Herein, we develop an active pharmaceutical ingredient poly(ionic liquid) (API PIL)-based MN patches containing salicylic acid (SA). The PIL-based MNs are simply prepared through photo-crosslinking of an imidazolium-type ionic liquid (IL) monomer in MN micro-molds, and following by anion exchange with salicylic acid anions (SA^-). The fabricated SA-loaded PIL-MNs exhibited therapeutic efficiency in the topical treatment of P. acnes infection in vitro and in vivo. These active pharmaceutical ingredient PIL-based MNs can improve acne treatment, demonstrating potential applications for skin diseases. STATEMENT OF SIGNIFICANCE: Microneedle (MN) patches can be used as platforms for transdermal delivery of various therapeutics to treat bacterial infection. Here, a facile strategy was developed to synthesize active pharmaceutical ingredient poly(ionic liquid)-based microneedle patches by anion-exchange with salicylic acid anion (SA^-). The fabricated SA-loaded PIL-MNs are active on not only anti-bacteria but also anti-inflammation in P. acnes treated mice, and may have potential applications for skin acne infection.

Ionic Liquids Toxicity-Benefits and Threats

Ionic liquids (ILs) are solvents with salt structures. Typically, they contain organic cations (ammonium, imidazolium, pyridinium, piperidinium or pyrrolidinium), and halogen, fluorinated or organic anions. While ILs are considered to be environmentally-friendly compounds, only a few reasons support this claim. This is because of high thermal stability, and negligible pressure at room temperature which makes them non-volatile, therefore preventing the release of ILs into the atmosphere. The expansion of the range of applications of ILs in many chemical industry fields has led to a growing threat of contamination of the aquatic and terrestrial environments by these compounds. As the possibility of the release of ILs into the environment s grow systematically, there is an increasing and urgent obligation to determine their toxic and antimicrobial influence on the environment. Many bioassays were carried out to evaluate the (eco)toxicity and biodegradability of ILs. Most of them have questioned their "green" features as ILs turned out to be toxic towards organisms from varied trophic levels. Therefore, there is a need for a new biodegradable, less toxic "greener" ILs. This review presents the potential risks to the environment linked to the application of ILs. These are the following: cytotoxicity evaluated by the use of human cells, toxicity manifesting in aqueous and terrestrial environments. The studies proving the relation between structures versus toxicity for ILs with special emphasis on directions suitable for designing safer ILs synthesized from renewable sources are also presented. The representants of a new generation of easily biodegradable ILs derivatives of amino acids, sugars, choline, and bicyclic monoterpene moiety are collected. Some benefits of using ILs in medicine, agriculture, and the bio-processing industry are also presented.

Pérez R, Ravula S, M. Strongin R, McDonough K, M. Warner I. 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.

Delivery of Small Molecule EF2 Kinase Inhibitor for Breast and Pancreatic Cancer Cells Using Hyaluronic Acid Based Nanogels

PURPOSE

To evalauted natural polymeric biomaterials including hyaluronic acid (HA) and its copolymeric form HA:Suc nanoparticles (NPs) as drug carrier systems for delivery of hydrophobic small molecule kinase EF2-kinase inhibitor in breast and pancreatic cancer cells.

METHODS

In vitro cellular uptake studies of Rhodamine 6G labaled HA:Suc nanoparticles were evaluated by using flow cytometry analysis and fluorescent microscopy in breast (MDA-MB-231 and MDA-MB-436) and pancreatic cancer cells (PANC-1 and MiaPaca-2). Besides, in vitro release study of compound A (an EF2-kinase inhibitor) as a model hydrophobic drug was performed in the cancer cells.

RESULTS

These biological evaluation studies indicated that HA and HA:Suc NPs provided a highly effective delivery of compound A were into breast and pancreatic cancer cells, leading to significant inhibition of cell proliferation and colony formation of breast and pancreatic cancer cells.

CONCLUSION

HA-sucrose NPs incorporating an EF2-Kinase inhibitor demonstrate significant biologic activity in breast and pancreatic cancer cells. This is the first study that shows natural polymeric drug carriers succesfully deliver a hydrofobic cancer drug into cancer cells. Graphical Abstract Nanoparticles based on HA:Suc are effective in delivering hydrofobic cancer drugs in breast and pancreatic cancers.

Bioinspired pH-Sensitive Fluorescent Peptidyl Nanoparticles for Cell Imaging

As an invaluable tool for biomedical research, the green fluorescent proteins (GFPs) make tumor cells, amyloid plaques, and pathogenic bacteria equally visible. Here, inspired by the chromophore of GFPs, we constructed a tyrosine-based peptide that show green luminescence in the aggregation state. Similar to the optical property of GFPs, the tyrosine-based peptidyl nanoparticles are stabilized by intermolecular hydrogen bonding and emit fluorescence when the Tyr residues bear phenolic anions. In addition, the tyrosine-based peptide is cell-permeable and endosome-escaped when conjuncted with the GPGR motif of human immunodeficiency virus and can be used for stable cell imaging due to its excellent photostability, pH-sensitivity and biocompatibility in physiological conditions. The results provide a promising pathway to construct peptidyl bioluminescent agents for biomedical applications.

Colorimetric Detection of Aliphatic Alcohols in β-Cyclodextrin Solutions

The sensitive, selective, and practical detection of aliphatic alcohols is a continuing technical challenge with significant impact in public health research and environmental remediation efforts. Reported herein is the use of a β-cyclodextrin derivative to promote proximity-induced interactions between aliphatic alcohol analytes and a brightly colored organic dye, which resulted in highly analyte-specific color changes that enabled accurate alcohol identification. Linear discriminant analysis of the color changes enabled 100% differentiation of the colorimetric signals obtained from methanol, ethanol, and isopropanol in combination with BODIPY and Rhodamine dyes. The resulting solution-state detection system has significant broad-based applicability because it uses only easily available materials to achieve such detection with moderate limits of detection obtained. Future research with this sensor system will focus on decreasing limits of detection as well as on optimizing the system for quantitative detection applications.

Modulating cellular cytotoxicity and phototoxicity of fluorescent organic salts through counterion pairing

Light-activated theranostics offer promising opportunities for disease diagnosis, image-guided surgery, and site-specific personalized therapy. However, current fluorescent dyes are limited by low brightness, high cytotoxicity, poor tissue penetration, and unwanted side effects. To overcome these limitations, we demonstrate a platform for optoelectronic tuning, which allows independent control of the optical properties from the electronic properties of fluorescent organic salts. This is achieved through cation-anion pairing of organic salts that can modulate the frontier molecular orbital without impacting the bandgap. Optoelectronic tuning enables decoupled control over the cytotoxicity and phototoxicity of fluorescent organic salts by selective generation of mitochondrial reactive oxygen species that control cell viability. We show that through counterion pairing, organic salt nanoparticles can be tuned to be either nontoxic for enhanced imaging, or phototoxic for improved photodynamic therapy.

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.

Photo- and Aromatic Stacking-Induced Green Emissive Peptidyl Nanoparticles for Cell Imaging and Monitoring of Nucleic Acid Delivery

Owing to their potential applications in biomedicine and biotechnology, peptide nanostructures that exhibit stable intrinsic fluorescence in the visible range are highly desired. This research proposes a facile strategy to construct peptidyl virus-like nanoparticles (NVPs) that show green luminescence by coassembly of two bioactive ferrocene-diphenylalanine-based (Fc-FF) peptides. The green fluorescence of NVPs was originated from the highly ordered structures assembled by the amphiphilic Fc-FF-based peptides via strong π-π stacking interactions. In the assemblies, Fc-FF chromophore can be hydrolyzed under the natural light irradiation, which eliminates the fluorophore quenching effect of Fc and increases the aromatic stacking interactions, thereby giving rise to strong fluorescent nanoparticles. The NVPs could cross cytomembrane barriers by virtue of the HIV V3 peptide and the nuclear localization signal, and could thus be used for long-term cell imaging with excellent photostability and biocompatibility in physiological condition. In addition, NVPs could package DNA and be used to monitor the delivery of DNA, indicating great potential in the tracking and monitoring of genetic biological processes.

Chemical-PDMS binding kinetics and implications for bioavailability in microfluidic devices

Microfluidic organ-on-chip devices constructed from polydimethylsiloxane (PDMS) have proven useful in studying both beneficial and adverse effects of drugs, supplements, and potential toxicants. Despite multiple advantages, one clear drawback of PDMS-based devices is binding of hydrophobic chemicals to their exposed surfaces. Chemical binding to PDMS can change the timing and extent of chemical delivery to cells in such devices, potentially altering dose-response curves. Recent efforts have quantified PDMS binding for selected chemicals. Here, we test a wider set of nineteen chemicals using UV-vis or infrared spectroscopy to characterize loss of chemical from solution in two setups with different PDMS-surface-to-solution-volume ratios. We find discernible PDMS binding for eight chemicals and show that PDMS binding is strongest for chemicals with a high octanol-water partition coefficient (log P > 1.85) and low H-bond donor number. Further, by measuring depletion and return of chemical from solution over tens to hundreds of hours and fitting these results to a first order model of binding kinetics, we characterize partitioning into PDMS in terms of binding capacities per unit surface area and both forward and reverse rate constants. These fitted parameters were used to model the impact of PDMS binding on chemical transport and bioavailability under realistic flow conditions and device geometry. The models predict that PDMS binding could alter in-device cellular exposures for both continuous and bolus dosing schemes by up to an order of magnitude compared to nominal input doses.

Formation of organosilica nanoparticles with dual functional groups and simultaneous payload entrapment

A mixed organosilane system for simultaneous formation of organosilica nanoparticles has been systematically studied for loading of various compounds with a wide range of log P values. The molecule-entrapping system was understood by investigating the effects of adjusting various experimental parameters on particle formation and molecule entrapment. Particularly, rhodamine 6 G (R6G) loaded colloidal particles were prepared and characterised in detail. The results show that whereas most molecules had entrapment efficiency (EE%) in the range of 20-80%, R6G exhibited near 100% efficiency. Moreover, the colloidal system can be tuned to incorporate R6G with the extent of entrapment spanning at least 2 orders of magnitude (i.e. from 0.04 to 4 mg) and a maximum EE% of 98%. In conclusion, the study demonstrates the promise of the proposed mixed organosilane system in forming colloidal particles containing multiple functional groups with selective loading of highly hydrophobic molecules.

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.

Self-assembly of Fluorescent Dehydroberberine Enhances Mitochondria-Dependent Antitumor Efficacy

Selective imaging and inducing mitochondrial dysfunction in tumor cells using mitochondria-targeting probes has become as a promising approach for cancer diagnosis and therapy. Here, we report the design of a fluorescent berberine analog, dehydroberberine (DH-BBR), as a new mitochondria-targeting probe capable of self-assembling into monodisperse organic nanoparticles (DTNPs) upon integration with a lipophilic counter anion, allowing for enhanced fluorescence imaging and treatment of tumors in living mice. X-ray crystallography revealed that the self-assembly process was attributed to a synergy of different molecular interactions, including π-π stacking, O⋅⋅⋅π interaction and electrostatic interaction between DH-BBR and counter anions. We demonstrated that DTNPs could efficiently enter tumor tissue following intravenous injection and enhance mitochondrial delivery of DH-BBR via an electrostatic interaction driven anion exchange process. Selective accumulation in the mitochondria capable of emitting strong fluorescence and causing mitochondrial dysfunction was achieved, enabling efficient inhibition of tumor growth in living mice. This study demonstrates promise for applying lipophilic anions to control molecular self-assembly and tune antitumor activity of mitochondria-targeting probes, which can facilitate to improve cancer treatment in vivo.

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

Rhodamine 6G nanoGUMBOS were templated with cyclodextrin to develop size tunable nanodrugs with enhanced cellular uptake and selective chemotherapeutic toxicity.

Mitochondria targeting IR780-based nanoGUMBOS for enhanced selective toxicity towards cancer cells

Herein, a simple counter-ion variation strategy is proposed and demonstrated for design of an array of near infrared IR780-based nanoGUMBOS (nanomaterials from a Group of Uniform Materials Based on Organic Salts) to produce enhanced anticancer activity. These nanomaterials were synthesized by direct nanoengineering of IR780-based GUMBOS using a reprecipitation method, without addition of any other materials. Thus, these novel nanomaterials can serve as carrier-free nanodrugs, providing several distinct advantages over conventional chemotherapeutics. Examination of the size and stability of these nanoGUMBOS indicates formation of approximately 100 nm nanoparticles that are stable under biological conditions. Interestingly, in vitro chemotherapeutic applications of these nanoGUMBOS indicate two to four-fold enhanced toxicity towards breast cancer cells as compared to the parent dye, while still maintaining minimal toxicity towards normal cells. The mechanism of cancer toxicity for these nanoGUMBOS was also examined by a study of their sub-cellular localization as well as using a mitochondrial toxicity assay. Analyses of data from these studies revealed that all nanoGUMBOS primarily accumulate in the mitochondria of cancer cells and produce dysfunction in the mitochondria to induce cell death. Using these studies, we demonstrate tunable properties of IR780-based nanoGUMBOS through simple variation of counter-ions, thus providing a promising strategy for future design of better nanomedicines to be used for cancer therapy.

Mitochondria targeting nanoGUMBOS were successfully fabricated based on self-assembly of IR780 GUMBOS with different counter-anions that show promising anticancer effects.

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

Synthesis and biological properties of galactofuranosyl-containing fluorescent dyes

Two fluorescent galactofuranosides were synthesized and their biological activities evaluated on non-infected and Leishmania infected macrophages. Both tagged scaffolds were able to penetrate macrophages. Compared to the activity of the parent octyl galactofuranoside used as a reference, the fluorescein-conjugate showed altered biological properties while the rhodamine 6G one synergistically acted with the lipid chain to significantly increase antiparasitic activity.

Strongly tricolor-emitting carbon dots synthesized by a combined aging–annealing route and their bio-application

A novel way has been established to make the FCDs with a very high QY, high stability, low cell cytotoxicity, and outstanding performance as a fluorescence probe.

2-Phenylbenzoxazole derivatives: a family of robust emitters of solid-state fluorescence

In addition to thermal, chemical and photochemical stability, the 2-phenylbenzoxazole fragment exhibits attractive emission properties in the solid state, thus leading to highly photoluminescent materials and sensors.

Emissive nanoparticles from pyridinium-substituted tetraphenylethylene salts: imaging and selective cytotoxicity towards cancer cells in vitro and in vivo by varying counter anions

Chemotherapeutics specifically targeting cancer cells without damaging healthy cells is the long-awaited goal of cancer treatment. In this paper, a series of nanoparticles (NanoTPES 1-4) assembled from pyridinium-substituted tetraphenylethylene salts were synthesized and investigated both in vitro and in vivo for this purpose. By changing the counter anions, NanoTPES 1-4 exhibit tunable emission colors, sizes and surface charges. NanoTPES 2 and 3 with tetraphenyl borate and tetra(4-chlorophenyl) borate as the respective anions selectively imaged and targeted mitochondria in cancer cells. Accordingly, these two nanoparticles specifically kill cancer cells with minimal effect on normal cells. Such selective cytotoxicity was attributed to the change of membrane potential and inhibition of ATP synthesis in the mitochondria of cancer cells. Furthermore, both NanoTPES 2 and 3 exhibited efficient tumor accumulation and tumor growth inhibition in vivo, with negligible systemic toxicity.