A Study of the Micellar Formation of N-Alkyl Betaine Ethyl Ester Chlorides Based on the Physicochemical Properties of Their Aqueous Solutions

In this study, a series of four surface-active compounds-N-alkyl betaine ethyl ester chlorides, CnBetC2Cl-were synthesized and characterized in aqueous solutions. As with other alkyl betaines, these amphiphiles can be practically used, for example, as co-surfactants and/or solubility enhancers acting according to hydrotropic or micellar mechanisms, depending on the alkyl chain length in the amine. We focused on the representatives of the medium alkyl chain length (C6-C12) to find the dependence between the alkyl chain length in N-alkyl betaine ethyl ester chlorides and the surface, volumetric, acoustic, and viscometric properties of their solutions. Ethyl esters, the derivatives of amino acids, were chosen to increase functionality and take advantage of possible hydrolysis in solutions at higher pH, which is also a key parameter in biodegradability. The micellization parameters were calculated based on the physicochemical characteristics. We focused our interest on the ester with a dodecyl substituent since we can compare and discuss its properties with some other C12 representatives that are available in literature. Surprisingly, its micellization characteristic is almost temperature-independent in the investigated temperature range, t = (15-45) °C. Particularly interesting are the results of dynamic light scattering (DLS), which show that the changes in physicochemical parameters of the C12 homolog around the CMC are caused by the two types of micelles of different sizes present in solutions.

Thermoplastic polyurethane/POSS nanohybrids: Synthesis, morphology, and biological properties

Recent studies show good osteoinductive properties of polyurethanes modified with polyhedral oligomeric silsesquioxanes (POSS). In this work, three types of POSS; propanediolisobutyl-POSS (PHI-POSS), disilanolisobutyl-POSS (DSI-POSS), and octahydroxybutyl-POSS (OCTA-POSS) were chemically incorporated into linear polyurethane based on an aliphatic isocyanate, hexamethylene diisocyanate (HDI), to obtain new nanohybrid PU-POSS materials. The full conversion of POSS was confirmed by Fourier transform infrared spectroscopy (FTIR-ATR) spectra of the model reactions with pure HDI. The materials obtained were investigated by FTIR, SEM-EDS, and DSC. The DSC studies showed the thermoplasticity of the obtained materials and apparently good recovery. 30-day immersion in SBF (simulated body fluid) revealed an increase in the rate of deposition of hydroxyapatite (HAp) for the highest POSS loadings, resulting in thick layers of hydroxyapatite (~60-40 μm), and the Ca/P ratio 1.67 (even 1.785). The structure and properties of the inorganic layer depend on the type of POSS, the number of hard segments, and those containing POSS, which can be tailored by changing the HDI/poly(tetramethylene glycol) (PTMG) ratio. Furthermore, the obtained composites revealed good biocompatibility, as confirmed by cytotoxicity tests conducted on two cell lines; normal human dermal fibroblasts (NHDF) and primary human osteoblasts (HOB). Adherent cells seeded on the tested materials showed viability even after a 48-h incubation. After this time, the population of viable, and proliferating cells exceeded 90%. Bioimaging studies have shown the fibroblast and osteoblast cells were well attached to the surface of the tested materials.

The Impact of Various Poly(vinylpyrrolidone) Polymers on the Crystallization Process of Metronidazole

In this paper, we propose one-step synthetic strategies for obtaining well-defined linear and star-shaped polyvinylpyrrolidone (linPVP and starPVP). The produced macromolecules and a commercial PVP K30 with linear topology were investigated as potential matrices for suppressing metronidazole (MTZ) crystallization. Interestingly, during the formation of binary mixtures (BMs) containing different polymers and MTZ, we found that linear PVPs exhibit maximum miscibility with the drug at a 50:50 weight ratio (w/w), while the star-shaped polymer mixes with MTZ even at a 30:70 w/w. To explain these observations, comprehensive studies of MTZ-PVP formulations with various contents of both components were performed using Fourier-transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. The obtained results clearly showed that the polymer's topology plays a significant role in the type of interactions occurring between the matrix and MTZ. Additionally, we established that for MTZ-PVP 50:50 and 75:25 w/w BMs, linear polymers have the most substantial impact on inhibiting the crystallization of API. The star-shaped macromolecule turned out to be the least effective in stabilizing amorphous MTZ at these polymer concentrations. Nevertheless, long-term structural investigations of the MTZ-starPVP 30:70 w/w system (which is not achievable for linear PVPs) demonstrated its complete amorphousness for over one month.

Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging

This paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the solvents that differed in their polarity (dichloromethane, acetonitrile, and methanol), including three methods of sample preparation using different pre-dissolving solvents such as dimethyl sulfoxide or chloroform. In the course of the research, it was found that there are strong interactions between the tested compounds and DMSO, which was visible as a change in the maximum emission band (λem) of the neat 3-imino-1,8-naphthalimides (λem = 470-480 nm) and between the compounds and DMSO (λem = 504-514 nm). The shift of the emission maximum that was associated with the presence of a small amount of DMSO in the sample was as much as 41 nm. In addition, the susceptibility of imines to hydrolysis in the methanol/water mixture with increasing water content and in the methanol/water mixture (v/v; 1:1) in the pH range from 1 to 12 was discussed. The studies showed that the compounds are hydrolysed in the CH3OH/H2O system in an acidic environment (pH in the range of 1 to 4). In addition, it was found that partial hydrolysis occurs in systems with an increased amount of water, and its degree may depend on the type of substituent on the imine bond. The compounds tended to quench the emission (ACQ) in the aggregated state and increase the emission related to the protonation of the imine bond. Moreover, it was found that the substituent in the imine bonds influenced a compound's individual photophysical properties. Biological tests, including cytotoxicity studies and cellular localisation, were also performed for all of the molecules. All of the tested compounds exhibited green fluorescence in the MCF-7 cells and showed co-localisation in the mitochondria, endoplasmic reticulum, and lysosome. The obtained photophysical and biological results indicate the promising potential use of the tested compounds as cellular dyes.

Identification and Biological Evaluation of a Water-Soluble Fullerene Nanomaterial as BTK Kinase Inhibitor

Introduction

Thanks to recent advances in synthetic methodology, water-soluble fullerene nanomaterials that interfere with biomolecules, especially DNA/RNA and selected proteins, have been found with tremendous potential for applications in nanomedicine. Herein, we describe the synthesis and evaluation of a water-soluble glycine-derived [60]fullerene hexakisadduct (HDGF) with T _h symmetry, which is a first-in-class BTK protein inhibitor.

Methods

We synthesized and characterized glycine derived [60]fullerene using NMR, ESI-MS, and ATR-FT-IR. DLS and zeta potential were measured and high-resolution transmission electron microscopy (HRTEM) observations were performed. The chemical composition of the water-soluble fullerene nanomaterial was examined by X-ray photoelectron spectrometry. To observe aggregate formation, the cryo-TEM analysis was carried out. The docking studies and molecular dynamic simulations were performed to determine interactions between HDGF and BTK. The in vitro cytotoxicity was evaluated on RAJI and K562 blood cancer cell lines. Subsequently, we examined the induction of cell death by autophagy and apoptosis by determining the expression levels of crucial genes and caspases. We investigated the direct association of HDGF on inhibition of the BTK signalling pathway by examining changes in the calcium levels in RAJI cells after treatment. The inhibitory potential of HDGF against non-receptor tyrosine kinases was evaluated. Finally, we assessed the effects of HDGF and ibrutinib on the expression of the BTK protein and downstream signal transduction in RAJI cells following anti-IgM stimulation.

Results

Computational studies revealed that the inhibitory activity of the obtained [60]fullerene derivative is multifaceted: it hampers the BTK active site, interacting directly with the catalytic residues, rendering it inaccessible to phosphorylation, and binds to residues that form the ATP binding pocket. The anticancer activity of produced carbon nanomaterial revealed that it inhibited the BTK protein and its downstream pathways, including PLC and Akt proteins, at the cellular level. The mechanistic studies suggested the formation of autophagosomes (increased gene expression of LC3 and p62) and two caspases (caspase-3 and -9) were responsible for the activation and progression of apoptosis.

Conclusion

These data illustrate the potential of fullerene-based BTK protein inhibitors as nanotherapeutics for blood cancer and provide helpful information to support the future development of fullerene nanomaterials as a novel class of enzyme inhibitors.

Anticancer potential and through study of the cytotoxicity mechanism of ionic liquids that are based on the trifluoromethanesulfonate and bis(trifluoromethylsulfonyl)imide anions

Ionic liquids (ILs) are known for their unique physicochemical properties. However, despite the great number of published papers, still little attention has been paid to their biological activity. Anticancer potential and the molecular mechanisms underlying the toxicity of these compounds are especially interesting and still unexplored. In the current work, a broad analysis of the cytotoxicity towards colon and breast cancers as well as glioblastoma of the ILs with pyridinium, piperidinium, pyrrolidinium, and imidazolium cations and trifluoromethanesulfonate or bis(trifluoromethylsulfonyl)imide anions indicated previously as the most toxic for normal human dermal fibroblasts were presented. In the case of MCF-7 cells, the activity of 1-decyl-3-methylimidazolium trifluoromethanesulfonate was more than twice as high as cisplatin. It was found that the inhibition of the cell cycle of colon cancer and glioblastoma cells occurs in different phases. More importantly, the different types of cell death were detected for both selected ILs, namely 1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-hexyl-3-methylimidazolium trifluoromethane-sulfonate, on colon cancer and glioblastoma, respectively, apoptosis and autophagy, confirmed at the gene and protein levels. Additionally, kinetic studies of the reactive oxygen species indicated that the tested ILs disturbed the cellular redox homeostasis.

Synthesis and applications of [60]fullerene nanoconjugate with 5-aminolevulinic acid and its glycoconjugate as drug delivery vehicles

The 5-aminolevulinic acid (5-ALA) prodrug is widely used in clinical applications, primarily for skin cancer treatments and to visualize brain tumors in neurosurgery. Unfortunately, its applications are limited by unfavorable pharmacological properties, especially low lipophilicity; therefore, efficient nanovehicles are needed. For this purpose, we synthesized and characterized two novel water-soluble fullerene nanomaterials containing 5-ALA and d-glucuronic acid components. Their physicochemical properties were investigated using NMR, XPS, ESI mass spectrometry, as well as TEM and SEM techniques. In addition, HPLC and fluorescence measurements were performed to evaluate the biological activity of the fullerene nanomaterials in 5-ALA delivery and photodynamic therapy (PDT); additional detection of selected mRNA targets was carried out using the qRT-PCR methodology. The cellular response to the [60]fullerene conjugates resulted in increased levels of ABCG2 and PEPT-1 genes, as determined by qRT-PCR analysis. Therefore, we designed a combination PDT approach based on two fullerene materials, C₆₀-ALA and C₆₀-ALA-GA, along with the ABCG2 inhibitor Ko143.

High pressure as a novel tool for the cationic ROP of γ-butyrolactone

In this study, we report the acid-catalyzed and high pressure assisted ring-opening polymerization (ROP) of γ-butyrolactone (GBL). The use of a dually-catalyzed approach combining an external physical factor and internal catalyst (trifluoromethanesulfonic acid (TfOH) or p-toluenesulfonic acid (PTSA)) enforced ROP of GBL, which is considered as hardly polymerizable monomer still remaining a challenge for the modern polymer chemistry. The experiments performed at various thermodynamic conditions (T = 278–323 K and p = 700–1500 MPa) clearly showed that the high pressure supported polymerization process led to obtaining well-defined macromolecules of better parameters (M_n = 2200–9700 g mol⁻¹; Đ = 1.05–1.46) than those previously reported. Furthermore, the parabolic-like dependence of both the molecular weight (M_W) and the yield of obtained polymers on variation in temperature and pressure at either isobaric or isothermal conditions was also noticed, allowing the determination of optimal conditions for the polymerization process. However, most importantly, this strategy allowed to significantly reduce the reaction time (just 3 h at room temperature) and increase the yield of obtained polymers (up to 0.62 g_PGBL/g_GBL). Moreover, despite using a strongly acidic catalyst, synthesized polymers remained non-toxic and biocompatible, as proven by the cytotoxicity test we performed in further analysis. Additional investigation (including MALDI-TOF measurements) showed that the catalyst selection affected not only M_W and yield but also the linear/cyclic form content in obtained macromolecules. These findings show the way to tune the properties of PGBL and obtain polymer suitable for application in the biomedical industry.

Well-defined poly(γ-butyrolactone) was synthesized with great efficiency via high pressure assisted cationic ROP of hardly polimerizable γ-butyrolactone.

Luminescence and Electrochemical Activity of New Unsymmetrical 3-Imino-1,8-naphthalimide Derivatives

A new series of 1,8-naphtalimides containing an imine bond at the 3-position of the naphthalene ring was synthesized using 1H, 13C NMR, FTIR, and elementary analysis. The impact of the substituent in the imine linkage on the selected properties and bioimaging of the synthesized compounds was studied. They showed a melting temperature in the range of 120-164 °C and underwent thermal decomposition above 280 °C. Based on cyclic and differential pulse voltammetry, the electrochemical behavior of 1,8-naphtalimide derivatives was evaluated. The electrochemical reduction and oxidation processes were observed. The compounds were characterized by a low energy band gap (below 2.60 eV). Their photoluminescence activities were investigated in solution considering the solvent effect, in the aggregated and thin film, and a mixture of poly(N-vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) (50:50 wt.%). They demonstrated low emissions due to photoinduced electron transport (PET) occurring in the solution and aggregation, which caused photoluminescence quenching. Some of them exhibited light emission as thin films. They emitted light in the range of 495 to 535 nm, with photoluminescence quantum yield at 4%. Despite the significant overlapping of its absorption range with emission of the PVK:PBD, incomplete Förster energy transfer from the matrix to the luminophore was found. Moreover, its luminescence ability induced by external voltage was tested in the diode with guest-host configuration. The possibility of compound hydrolysis due to the presence of the imine bond was also discussed, which could be of importance in biological studies that evaluate 3-imino-1,8-naphatalimides as imaging tools and fluorescent materials for diagnostic applications and molecular bioimaging.

Novel Benzenesulfonate Scaffolds with a High Anticancer Activity and G2/M Cell Cycle Arrest

Sulfonates, unlike their derivatives, sulphonamides, have rarely been investigated for their anticancer activity. Unlike the well-known sulphonamides, esters are mainly used as convenient intermediates in a synthesis. Here, we present the first in-depth investigation of quinazoline sulfonates. A small series of derivatives were synthesized and tested for their anticancer activity. Based on their structural similarity, these compounds resemble tyrosine kinase inhibitors and the p53 reactivator CP-31398. Their biological activity profile, however, was more related to sulphonamides because there was a strong cell cycle arrest in the G2/M phase. Further investigation revealed a multitargeted mechanism of the action that corresponded to the p53 protein status in the cell. Although the compounds expressed a high submicromolar activity against leukemia and colon cancers, pancreatic cancer and glioblastoma were also susceptible. Apoptosis and autophagy were confirmed as the cell death modes that corresponded with the inhibition of metabolic activity and the activation of the p53-dependent and p53-independent pathways. Namely, there was a strong activation of the p62 protein and GADD44. Other proteins such as cdc2 were also expressed at a higher level. Moreover, the classical caspase-dependent pathway in leukemia was observed at a lower concentration, which again confirmed a multitargeted mechanism. It can therefore be concluded that the sulfonates of quinazolines can be regarded as promising scaffolds for developing anticancer agents.

Key Properties of a Bioactive Ag-SiO2/TiO2 Coating on NiTi Shape Memory Alloy as Necessary at the Development of a New Class of Biomedical Materials

Recent years have seen the dynamic development of methods for functionalizing the surface of implants using biomaterials that can mimic the physical and mechanical nature of native tissue, prevent the formation of bacterial biofilm, promote osteoconduction, and have the ability to sustain cell proliferation. One of the concepts for achieving this goal, which is presented in this work, is to functionalize the surface of NiTi shape memory alloy by an atypical glass-like nanocomposite that consists of SiO2-TiO2 with silver nanoparticles. However, determining the potential medical uses of bio(nano)coating prepared in this way requires an analysis of its surface roughness, tribology, or wettability, especially in the context of the commonly used reference coat-forming hydroxyapatite (HAp). According to our results, the surface roughness ranged between (112 ± 3) nm (Ag-SiO2)-(141 ± 5) nm (HAp), the water contact angle was in the range (74.8 ± 1.6)° (Ag-SiO2)-(70.6 ± 1.2)° (HAp), while the surface free energy was in the range of 45.4 mJ/m2 (Ag-SiO2)-46.8 mJ/m2 (HAp). The adhesive force and friction coefficient were determined to be 1.04 (Ag-SiO2)-1.14 (HAp) and 0.247 ± 0.012 (Ag-SiO2) and 0.397 ± 0.034 (HAp), respectively. The chemical data showed that the release of the metal, mainly Ni from the covered NiTi substrate or Ag from Ag-SiO2 coating had a negligible effect. It was revealed that the NiTi alloy that was coated with Ag-SiO2 did not favor the formation of E. coli or S. aureus biofilm compared to the HAp-coated alloy. Moreover, both approaches to surface functionalization indicated good viability of the normal human dermal fibroblast and osteoblast cells and confirmed the high osteoconductive features of the biomaterial. The similarities of both types of coat-forming materials indicate an excellent potential of the silver-silica composite as a new material for the functionalization of the surface of a biomaterial and the development of a new type of functionalized implants.

Photofunctionalization effect and biological ageing of PEEK, TiO2 and ZrO2 abutments material

The aim of this study was to evaluate the effectiveness of UVC photofunctionalization in removing the surface carbon contamination compounds from the most used surfaces utilized in dental implantology: TiO₂, ZrO₂ and PEEK. Machined samples were treated by UVC light in an Ushio Therabeam SuperOsseo® device for 12 min each. Non-treated disks were set as controls. X-Ray photoelectron spectroscopy was used to monitor the changes in surface chemical composition. Photofunctionalization of the PEEK material has been analyzed here for the first time. The removal of hydrocarbons allowed by UVC irradiation was nearly twofold, and irradiation simultaneously led to an increase of H-O-C=O bonds. For TiO₂ and ZrO₂ surfaces, the loss of hydrocarbons detected after UVC irradiation was threefold. The chemical stability of surfaces when left at atmospheric conditions after UVC irradiation was monitored during 10 weeks. After 6 weeks the carbon contamination on TiO₂ surfaces returned to the level before UVC treatment, while for ZrO₂ and PEEK it was 75% and 60% of its initial value, respectively. None of the materials tested displayed any toxicity towards human fibroblasts cultured in direct contact with them, confirming their potential employment for manufacturing of implant abutments. UVC photofunctionalization can be thus regarded as a valid method in order to reverse the detrimental effects of biological ageing of implant surfaces.

An Organic-Inorganic Hybrid Nanocomposite as a Potential New Biological Agent

To solve the problem of human diseases caused by a combination of genetic and environmental factors or by microorganisms, intense research to find completely new materials is required. One of the promising systems in this area is the silver-silica nanocomposites and their derivatives. Hence, silver and silver oxide nanoparticles that were homogeneously distributed within a silica carrier were fabricated. Their average size was d = (7.8 ± 0.3) nm. The organic polymers (carboxymethylcellulose (CMC) and sodium alginate (AS)) were added to improve the biological features of the nanocomposite. The first system was prepared as a silver chlorine salt combination that was immersed on a silica carrier with coagulated particles whose size was d = (44.1 ± 2.3) nm, which coexisted with metallic silver. The second system obtained was synergistically interacted metallic and oxidized silver nanoparticles that were distributed on a structurally defective silica network. Their average size was d = (6.6 ± 0.7) nm. Physicochemical and biological experiments showed that the tiny silver nanoparticles in Ag/SiO₂ and Ag/SiO₂@AS inhibited E. coli, P. aeruginosa, S. aureus, and L. plantarum's cell growth as well as caused a high anticancer effect. On the other hand, the massive silver nanoparticles of Ag/SiO₂@CMC had a weaker antimicrobial effect, although they highly interacted against PANC-1. They also generated reactive oxygen species (ROS) as well as the induction of apoptosis via the p53-independent mechanism.

New derivatives of 4'-phenyl-2,2':6',2″-terpyridine as promising anticancer agents

Terpyridine derivatives are known from their broad application including anticancer properties. In this work we present the newly synthesized 4'-phenyl-2,2':6',2″-terpyridine group with high antiproliferative activity. We suggest that these compounds influence cellular redox homeostasis. Cancer cells are particularly susceptible to any changes in the redox balance because of their handicapped and inefficient antioxidant cellular systems. The antiproliferative activity of the studied compounds was tested on five different cell lines that represent several types of tumours; glioblastoma, leukemia, breast, pancreatic and colon. Additionally, we also tested their selectivity towards normal cells. We performed molecular biology studies in order to detect the response of a cell to its treatment with the compounds that were tested. We looked at the in-depth changes in the proteins and cellular pathways that lead to cell cycle inhibition (G0/G1 and S), and consequently, death on the apoptosis and autophagy pathways. We proved that the studied compounds targeted DNA as well. Special attention was paid to the targets connected with ROS generation.

Advanced SA/PVA-based hydrogel matrices with prolonged release of Aloe vera as promising wound dressings

This work focuses on the influence of different amounts (5, 10, 15, 20 and 25%, v/v) of solution of Aloe vera on the chemical structure and properties of sodium alginate/poly(vinyl alcohol) hydrogel films. The polymeric matrix was prepared following the chemical cross-linking method using poly(ethylene glycol) diacrylate (PEGDA, Mn = 700 g/mol) as a cross-linking agent. First, the gel fractions of the modified hydrogels were determined and their swelling behavior in distilled water and phosphate-buffered saline (PBS) was tested. Subsequently, the following properties of the modified hydrogel materials were studied: structural (FT-IR spectra analysis), morphological (SEM analysis) and mechanical (tensile strength, elongation at break and hardness). Moreover, a thermal analysis (TG/DTG and DSC) confirmed that the SA/PVA hydrogels containing Aloe vera exhibited slightly higher thermal stability than the unmodified hydrogels, which allows concluding that a rigid and thermally stable three-dimensional structure had been obtained. Additionally, the release profile of polysaccharides from the hydrogel matrix was evaluated in PBS at 37 °C. The results show that the active substance was released in a prolonged manner, gradually, even for a week. It was found that the presence of Aloe vera inside the cross-linked polymeric network improved the active substance delivery properties of the hydrogel films. When greater amounts of Aloe vera were applied, the hydrogel had an irregular surface structure, as revealed by SEM images. The chemical structure was confirmed on the basis of an FT-IR spectral analysis. Concluding, SA/PVA/Aloe vera matrices are promising compounds and deserve further studies towards application in interactive wound dressings. Additionally, the cytotoxicity of the materials was studied and the results indicated good adhesion properties and no toxicity. In vitro experiments performed on normal human dermal fibroblasts proved excellent cell attachment on the Aloe vera hydrogel discs, which promoted cells spreading and proliferation.

Live cell imaging by 3-imino-(2-phenol)-1,8-naphthalimides: The effect of ex vivo hydrolysis

A series of 3-amino-N-substituted-1,8-naphthalimides and their salicylic Schiff base derivatives were synthesized. The structure of the obtained compounds was confirmed using ¹H and ¹³C NMR, FT-IR spectroscopy and elemental analysis and COSY and HMQC for the representative molecules. The photophysical (UV-Vis, PL) and biological properties of all of the prepared compounds were studied. It was found that the amine with the n-hexyl group in EtOH had the highest PL quantum yield (Ф = 85%) compared to the others. Moreover, the chelating properties of the azomethines with the n-hexyl group (1a, 1b, 1c) were tested against various cations (Al³⁺, Ba²⁺, Co²⁺, Cu²⁺, Cr³⁺, Fe²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺, Sr²⁺ and Zn²⁺) in an acetonitrile, acetone and PBS/AC mixture. Compounds that contained the electron withdrawing groups (-Br, -I) had the ability to chelate most of the studied cations, while the unsubstituted derivative chelated only the trivalent cations such as Al³⁺, Cr³⁺ and Fe³⁺ in acetonitrile. The effect of the environment on the keto-enol tautomeric equilibrium was also demonstrated, especially in the case of the derivative with a bromine atom. The biological studies showed that the tested molecules had no cytotoxicity. Additionally, the ability to image intracellular organelles such as the mitochondria and endoplasmic reticulum was revealed. The crucial role of the hydrolysis of imines for cellular imaging was presented.

Theoretical and Experimental Investigations of Large Stokes Shift Fluorophores Based on a Quinoline Scaffold

A series of novel styrylquinolines with the benzylidene imine moiety were synthesized and spectroscopically characterized for their applicability in cellular staining. The spectroscopic study revealed absorption in the ultraviolet-visible region (360-380 nm) and emission that covered the blue-green range of the light (above 500 nm). The fluorescence quantum yields were also determined, which amounted to 0.079 in the best-case scenario. The structural features that are behind these values are also discussed. An analysis of the spectroscopic properties and the theoretical calculations indicated the charge-transfer character of an emission, which was additionally evaluated using the Lippert-Mataga equation. Changes in geometry in the ground and excited states, which had a significant influence on the emission process, are also discussed. Additionally, the capability of the newly synthesized compounds for cellular staining was also investigated. These small molecules could effectively penetrate through the cellular membrane. Analyses of the images that were obtained with several of the tested styrylquinolines indicated their accumulation in organelles such as the mitochondria and the endoplasmic reticulum.

A [60]fullerene nanoconjugate with gemcitabine: synthesis, biophysical properties and biological evaluation for treating pancreatic cancer

Background

The first-line chemotherapy drug that is used to treat pancreatic ductal adenocarcinoma is gemcitabine. Unfortunately, its effectiveness is hampered by its chemo-resistance, low vascularization and drug biodistribution limitations in the tumor microenvironment. Novel nanotherapeutics must be developed in order to improve the prognosis for patients with pancreatic cancer.

Results

We developed a synthetic methodology for obtaining a water-soluble nanoconjugate of a [60]fullerene-glycine derivative with the FDA-approved drug gemcitabine (nanoC60GEM). The proposed synthetic protocol enables a highly water-soluble [60]fullerene-glycine derivative (6) to be obtained, which was next successfully conjugated with gemcitabine using the EDCI/NHS carbodiimide protocol. The desired nanoconjugate was characterized using mass spectrometry and DLS, IR and XPS techniques. The photogeneration of singlet oxygen and the superoxide anion radical were studied by measuring 1O2 near-infrared luminescence at 1270 nm, followed by spin trapping of the DMPO adducts by EPR spectroscopy. The biological assays that were performed indicate that there is an inhibition of the cell cycle in the S phase and the induction of apoptosis by nanoC60GEM.

Conclusion

In this paper, we present a robust approach for synthesizing a highly water-soluble [60]fullerene nanoconjugate with gemcitabine. The performed biological assays on pancreatic cancer cell lines demonstrated cytotoxic effects of nanoC60GEM, which were enhanced by the generation of reactive oxygen species after blue LED irradiation of synthesized fullerene nanomaterial.

Impact of temperature on the physicochemical, structural and biological features of copper-silica nanocomposites

Classical wet chemical synthesis was used to fabricate a hybrid composite that contained copper nanoparticles (average size ∼1 nm), which were embedded into a silicon oxide carrier. The structural and chemical alternations in the copper-functionalized silica were investigated in systems that were sintered at 573 K, 873 K, 1173 K, and 1473 K. A general trend, which was associated with the transformation of metallic copper with a cubic structure into copper(II) oxide with a monoclinic structure in the heat-treated systems, was found. XPS and FTIR spectroscopies also revealed the presence of copper(I) oxide, which formed a shell around the CuO. SEM and TEM showed gradual densification of the hybrid system at ever higher sintering temperatures, which corresponded with the gradual copper agglomeration. A temperature of 873 K was determined to be the temperature at which amorphous silica was transformed into cristoballite and tridymite, as well as the formation of a bulk-like copper structure. In relation to the physicochemical and structural data, high antimicrobial features that had a relatively low toxicity effect on the normal human fibroblasts (NHDF) below 250 mg/L was found for the initial copper-silica composite and the samples that were sintered at 573 K. In turn, a significant decrease in the biological impact was observed in the samples that were sintered at temperatures above 573 K. As a result, the paper discusses the model of structural modifications in copper-silica nanocomposite concerning their biological impact that was developed.

Impact of thiosemicarbazones on the accumulation of PpIX and the expression of the associated genes

Thiosemicarbazone derivatives are known for their broad biological activity including their antitumor potency. The aim of the current study was to examine the effect of a novel series of non-toxic iron chelators on the accumulation of protoporphyrin IX after external 5-aminolevulonic acid administration. From this series we selected one the most promising derivative which causes a pronounced increase in the concentration of protoporphyrin IX. The increase of the photosensitizer concentration is necessary for the trigger the efficient therapeutic effect of the photodynamic reaction. For selected compound 2 we performed an examination of a panel of the genes that are involved in the heme biosynthesis and degradation. Results indicated the crucial roles of ferrochelatase and heme oxygenase in the described processes. Surprisingly, there was a strict dependence on the type of the tested cell line. A decrease in the expression of the two aforementioned enzymes after incubation with compound 2 and 5-aminolevulonic acid is a commonly known fact and we detected this trend for the MCF-7 and HCT 116 cell lines. However, we noticed the upregulation of the tested targets for the Hs683 cells. These unconventional results prompted us to do a more in-depth analysis of the described processes. In conclusion, we found that compound 2 is a novel, highly effective booster of photodynamic therapy that has prospective applications.

Physicochemical and structural features of heat treated silver-silica nanocomposite and their impact on biological properties

In the last few decades, many nanostructures with varying properties and possible applications have been developed. These materials have been intended to work in various environmental temperature conditions. In this context, the main challenge has been to comprehend the impact of synergic interaction between individual elements included in non-annealed materials in relation to systems subjected to temperature impact. Another problem has corresponded to the impact of thermal modification on organisms such as bacteria and human cells. Such problems can be solved by the fabrication of a nanocomposite with mono-dispersed 8 nm silver (Ag⁰ or Ag⁺) embedded into a silica carrier, followed by the analysis of the impact of heat treatment under various temperature conditions on its physicochemical features. Therefore, methodical studies reported in this text have shown an increase of silver particle size up to 170 nm, a decrease of its concentration, as well as the formation of sub-nanometer Ag⁺ and/or Ag²⁺ clusters as the temperature rises to 1173 K. In turn, the structurally disordered silica carrier had been entirely transformed to cristobalite and tridymite only at 1473 K as well as partial reduction of Ag²⁺ to Ag⁺. Simultaneously, inhibition of growth of Gram-positive and Gram-negative bacteria, as well as an increase in cytotoxicity towards human cells was observed as the temperature rose. As a final point, for the first time, a "pseudo" phase diagram of the structural alterations in the Ag/SiO₂ nanocomposite has been created, as well as a model of silver-silica transformation to biological systems has been developed.

Design and synthesis of anticancer 1-hydroxynaphthalene-2-carboxanilides with a p53 independent mechanism of action

A series of 116 small-molecule 1-hydroxynaphthalene-2-carboxanilides was designed based on the fragment-based approach and was synthesized according to the microwave-assisted protocol. The biological activity of all of the compounds was tested on human colon carcinoma cell lines including a deleted TP53 tumor suppressor gene. The mechanism of activity was studied according to the p53 status in the cell. Several compounds revealed a good to excellent activity that was similar to or better than the standard anticancer drugs. Some of these appeared to be more active against the p53 null cells than their wild-type counterparts. Intercalating the properties of these compounds could be responsible for their mechanism of action.

Toward the Development of an Innovative Implant: NiTi Alloy Functionalized by Multifunctional β-TCP+Ag/SiO2 Coatings

In recent years, one of the more important and costly problems of modern medicine is the need to replace or supplement organs in order to improve the quality of human life. In this field, promising solutions seem to have been implants which are based on NiTi alloys with shape memory effects. Unfortunately, this material is susceptible to the corrosion and release of toxic nickel to the human organism. Hence, its application as a long-term material is strongly limited. Therefore, this paper presents a new solution which should help to improve the functionality of the NiTi alloy and elongate its medical stability to use. The idea was focused on functionalization of the implant surface by a biocompatible, multifunctional coating without any impact on the features of the substrate, i.e., the martensitic transformation responsible for shape memory effects. For this purpose, we prepared a colloidal suspension, composed of β-TCP (particle size ∼450 nm) and the Ag/SiO₂ nanocomposite which due to the electrophoretic deposition (EPD) led to the formation of structurally atypical calcium phosphosilicate coating. Those biomaterials formed a crack-free coating, adhering well to the NiTi surface when distributed over the entire surface, with low concentration of metallic and oxide silver (<3 at. %). At the same time, the coat-forming materials had resulted in the growth of a Gram-negative bacterial biofilm. Additionally, the additive of the silver-silica composite enhances cell proliferation, effectively a few times higher than commonly used coat-forming materials (e.g., pure β-TCP).

Anticancer activity of the thiosemicarbazones that are based on di-2-pyridine ketone and quinoline moiety

Thiosemicarbazones (TSC) are a subclass of iron-chelating agents that are believed to have an anticancer activity. The high potential for the application of this compound class can be illustrated by a fact that three TSC have entered clinical trials. The ability to chelate metal ions results in several biochemical changes in the cellular metabolism and growth. An important factor that determines the antitumor activity of TSC is a level of iron regulatory proteins and the antioxidant potential that is specific for each type of cancer cell. However, despite the increasing interest in TSC, their mechanism of anticancer activity is still unclear. For a more effective and rational design, it is crucial to determine and describe the abovementioned issues. In this report, we describe a series of new TSC that are designed on the four main structural scaffolds. The anticancer activity of these compounds was evaluated against a panel of cancer cell lines including colon and breast cancers and gliomas. Special attention was paid to the metal-dependent proteins. The impact of the tested TSC on the cell cycle and redox homeostasis was also determined. These results confirm a p53-independent mechanism of apoptosis.

Influence of the substituent D/A at the 1,2,3-triazole ring on novel terpyridine derivatives: synthesis and properties

In this study, we newly designed and developed a synthesis route based on the 1,3-dipolar cycloaddition of the derivatives of 4′-(1,2,3-triazol-4-yl)phenyl-2,2′:6′,2′′-terpyridine with various (hetero)aryl substituents, differing in electronic character, on a triazol ring. The obtained compounds were comprehensively characterized by UV-Vis spectroscopy and electrochemical and thermal studies. Moreover, preliminary biological tests were conducted. The investigation allowed the selection of materials with the most promising properties with particular emphasis on the nature of the substituents. In addition, theoretical studies (DFT and TD-DFT) were performed to verify the comprehensive understanding of experimental results.

The change in the substituents (D/A) at the 1,2,3-triazole ring of terpyridine derivatives shows a strong influence on the photophysical and biological properties of these derivatives.

Piperazinyl fragment improves anticancer activity of Triapine

A new class of TSCs containing piperazine (piperazinylogs) of Triapine, was designed to fulfill the di-substitution pattern at the TSCs N4 position, which is a crucial prerequisite for the high activity of the previously obtained TSC compounds–DpC and Dp44mT. We tested the important physicochemical characteristics of the novel compounds L¹-L¹². The studied ligands are neutral at physiological pH, which allows them to permeate cell membranes and bind cellular Fe pools more readily than less lipid-soluble ligands, e.g. DFO. The selectivity and anti-cancer activity of the novel TSCs were examined in a variety of cancer cell types. In general, the novel compounds demonstrated the greatest promise as anti-cancer agents with both a potent and selective anti-proliferative activity. We investigated the mechanism of action more deeply, and revealed that studied compounds inhibit the cell cycle (G1/S phase). Additionally we detected apoptosis, which is dependent on cell line’s specific genetic profile. Accordingly, structure-activity relationship studies suggest that the combination of the piperazine ring with Triapine allows potent and selective anticancer chelators that warrant further in vivo examination to be identified. Significantly, this study proved the importance of the di-substitution pattern of the amine N4 function.

The role of oxidative stress in activity of anticancer thiosemicarbazones

Thiosemicarbazones are chelators of transition metals such as iron or copper whose anticancer potency is intensively investigated. Although two compounds from this class have entered clinical trials, their precise mechanism of action is still unknown. Recent studies have suggested the mobilization of the iron ions from a cell, as well as the inhibition of ribonucleotide reductase, and the formation of reactive oxygen species. The complexity and vague nature of this mechanism not only impedes a more rational design of novel compounds, but also the further development of those that are highly active that are already in the preclinical phase. In the current work, a series of highly active thiosemicarbazones was studied for their antiproliferative activity in vitro. Our experiments indicate that these complexes have ionophoric properties and redox activity. They appeared to be very effective generating reactive oxygen species and deregulating the antioxidative potential of a cell. Moreover, the genes that are responsible for antioxidant capacity were considerably deregulated, which led to the induction of apoptosis and cell cycle arrest. On the other hand, good intercalating properties of the studied compounds may explain their ability to cleave DNA strands and to also poison related enzymes through the formation of reactive oxygen species. These findings may help to explain the particularly high selectivity that they have over normal cells, which generally have a stronger redox equilibrium.

Iron Chelators and Exogenic Photosensitizers. Synergy through Oxidative Stress Gene Expression

In non-invasive anticancer photodynamic therapy (PDT), a nontoxic photosensitizer (PS), which is activated by visible light, is used as a magic bullet that selectively destroys cancer cells. Recently, we described the combined therapy of 5-aminolevulinic acid (ALA-PDT) with thiosemicarbazone (TSC), i.e. an iron-chelating agent. This resulted in a strong synergistic effect. Herein, we investigated a novel strategy using a combination of PDT consist of the xenobiotic-porphyrin type PS with TSC. We observed a synergistic effect for all of the pairs of TSC-PS. This approach can be rationalized by the fact that both chlorin and TSC can affect the generation of reactive oxygen species (ROS). In order to elucidate the plausible mechanism of action, we also combined the investigated PSs with DFO, which forms complexes that are redox inactive. We detected a slight antagonism or additivity for this combination. This may suggest that the ability of an iron chelator (IC) to participate in the production of ROS and the generation of oxidative stress is important.

Unique properties of silver and copper silica-based nanocomposites as antimicrobial agents

The paper reports a new route for the fabrication and determination of physicochemical properties and biological activity, of metallic silica-based nanostructure (Ag/SiO₂, Cu/SiO₂).

Small molecule glycoconjugates with anticancer activity

Glycoconjugates are combinations of sugar moieties with organic compounds. Due to their biological resemblance, such structures often have properties that are desirable for drugs. In this study we designed and synthesised several glycoconjugates from small molecular quinolines and substituted gluco- and galactopyranosyl amines. Although the parent quinoline compounds were inactive in affordable concentrations, the glycoconjugates that were obtained appeared to be cytotoxic against cancer cells at the micromolar level. When combined with copper ions, their activity increased even further. Their mechanism of action is connected to the formation of reactive oxygen species and the intercalation of DNA.

Design, Synthesis and In Vitro Activity of Anticancer Styrylquinolines. The p53 Independent Mechanism of Action

A group of styrylquinolines were synthesized and tested for their anti-proliferative activity. Anti-proliferative activity was evaluated against the human colon carcinoma cell lines that had a normal expression of the p53 protein (HCT116 p53^+/+) and mutants with a disabled TP53 gene (HCT116 p53^-/-) and against the GM 07492 normal human fibroblast cell line. A SAR study revealed the importance of Cl and OH as substituents in the styryl moiety. Several of the compounds that were tested were found to have a marked anti-proliferative activity that was similar to or better than doxorubicin and were more active against the p53 null than the wild type cells. The cellular localization tests and caspase activity assays suggest a mechanism of action through the mitochondrial pathway of apoptosis in a p53-independent manner. The activity of the styrylquinoline compounds may be associated with their DNA intercalating ability.

Synthesis of New Styrylquinoline Cellular Dyes, Fluorescent Properties, Cellular Localization and Cytotoxic Behavior

New styrylquinoline derivatives with their photophysical constants are described. The synthesis was achieved via Sonogashira coupling using the newly developed heterogeneous nano-Pd/Cu catalyst system, which provides an efficient synthesis of high purity products. The compounds were tested in preliminary fluorescent microscopy studies to in order to identify their preferable cellular localization, which appeared to be in the lipid cellular organelles. The spectroscopic properties of the compounds were measured and theoretical TD-DFT calculations were performed. A biological analysis of the quinolines that were tested consisted of cytotoxicity assays against normal human fibroblasts and colon adenocarcinoma cells. All of the compounds that were studied appeared to be safe and indifferent to cells in a high concentration range. The presented results suggest that the quinoline compounds that were investigated in this study may be valuable structures for development as fluorescent dyes that could have biological applications.

Exploring the anti-cancer activity of novel thiosemicarbazones generated through the combination of retro-fragments: dissection of critical structure-activity relationships

Thiosemicarbazones (TSCs) are an interesting class of ligands that show a diverse range of biological activity, including anti-fungal, anti-viral and anti-cancer effects. Our previous studies have demonstrated the potent in vivo anti-tumor activity of novel TSCs and their ability to overcome resistance to clinically used chemotherapeutics. In the current study, 35 novel TSCs of 6 different classes were designed using a combination of retro-fragments that appear in other TSCs. Additionally, di-substitution at the terminal N4 atom, which was previously identified to be critical for potent anti-cancer activity, was preserved through the incorporation of an N4-based piperazine or morpholine ring. The anti-proliferative activity of the novel TSCs were examined in a variety of cancer and normal cell-types. In particular, compounds 1d and 3c demonstrated the greatest promise as anti-cancer agents with potent and selective anti-proliferative activity. Structure-activity relationship studies revealed that the chelators that utilized “soft” donor atoms, such as nitrogen and sulfur, resulted in potent anti-cancer activity. Indeed, the N,N,S donor atom set was crucial for the formation of redox active iron complexes that were able to mediate the oxidation of ascorbate. This further highlights the important role of reactive oxygen species generation in mediating potent anti-cancer activity. Significantly, this study identified the potent and selective anti-cancer activity of 1d and 3c that warrants further examination.

Iron chelators in photodynamic therapy revisited: synergistic effect by novel highly active thiosemicarbazones

In photodynamic therapy (PDT), a noninvasive anticancer treatment, visible light, is used as a magic bullet selectively destroying cancer cells by a photosensitizer that is nontoxic in the dark. Protoporphyrin IX (PpIX) is a natural photosensitizer synthesized in the cell, which is also a chelating agent that if bonded to Fe(2+) forms heme, a central component of hemoglobin. Therefore, xenobiotic iron chelators can disturb iron homeostasis, increasing the accumulation of PpIX, obstructing the last step of heme biosynthesis, and enhancing PDT efficiency. However, the attempts to use this promising idea have not proved to be hugely successful. Herein, we revisited this issue by analyzing the application of iron chelators highly toxic in the dark, which should have higher Fe(2+) affinity than the nontoxic chelators used so far. We have designed and prepared thiosemicarbazones (TSC) with the highest dark cellular cytotoxicity among TSCs ever reported. We demonstrate that compound 2 exerts powerful PDT enhancement when used in combination with 5-aminolevulinic acid (ALA), a precursor of PpIX.

Investigation of the biological properties of (hetero)aromatic thiosemicarbazones

Two series of thiosemicarbazone-based iron chelators (twenty-seven compounds) were designed and synthesized using a microwave-assisted approach. Quinoline and halogenated phenyl were selected as parent scaffolds on the basis of a similarity search. The lipophilicity of the synthesized compounds was measured using HPLC and then calculated. Primary in vitro screening of the synthesized compounds was performed against eight pathogenic fungal strains. Only a few compounds showed moderate activity against fungi, and (E)-2-(quinolin-2-ylvinyl)-N,N-dimethylhydrazine-carbothioamide appeared to be more effective than fluconazole against most of the fungal strains tested. Antiproliferative activity was measured using a human colon cancer cell line (HCT-116). Several of the tested compounds showed submicromolar antiproliferative activity. Compounds were also tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The structure-activity relationships are discussed for all of the compounds.

Investigating the anti-proliferative activity of styrylazanaphthalenes and azanaphthalenediones

A group of styrylazanaphthalenes and azanaphthalenediones were synthesized and tested for their anti-proliferative activity. Most of the compounds were obtained with the use of microwave-assisted synthesis. The lipophilicity of the compounds was measured by RP-HPLC and their anti-proliferative activity was assayed against the human SK-N-MC neuroepithelioma and HCT116 human colon carcinoma cell lines. Active compounds were also tested in clonogenity and comet assays. Several quinazolinone and styrylquinazoline analogues were found to have markedly greater anti-proliferative activity than desferoxamine and cis-platin.