Cell Toxicity Evaluation Research Articles

Chitosan-chelated carbon dots-based nanozyme of extreme stability with super peroxidase activity and antibacterial ability for wound healing

Bacterial infection often leads to failed wound healing, causing one-third of death cases globally. However, antibacterial nanomaterials and natural enzymes face limitations including low antibacterial efficiency, lack of catalytic performance, low safety, and instability. Therefore, a new Fe/N-doped chitosan-chelated carbon dot-based nanozyme CS@Fe-N CDs was developed, which showed multiple advantages such as highly efficient antibacterial activity, excellent peroxidase-like activity, high stability, and high biocompatibility, shortening the wound healing time. The ultra-small (6.14 ± 3.38 nm) CS@Fe-N CDs nanozyme accelerated the H2O2 to ·OH conversion, exhibiting excellent antibacterial performance against Staphylococcus aureus. The antibacterial activity was increased by over 2000-fold after catalysis. The CS@Fe-N CDs nanozyme also displayed outstanding peroxidase activity (Vmax/Km = 1.77 × 10−6/s), 8.8-fold higher than horseradish peroxidase. Additionally, the CS@Fe-N CDs nanozyme exhibited high stability at broad pH values (pH 1–12) and temperature ranges (20–90 °C). In vitro evaluation of cell toxicity proved that the CS@Fe-N CDs nanozyme had negligible cytotoxicity. In vivo, wound healing experiments demonstrated that the CS@Fe-N CDs could shorten the healing time of rat wounds by at least 4 days, and even had a better curative effect than penicillin. In conclusion, this therapeutic platform provides an effective antibacterial and biologically safe healing strategy for skin wounds.

Degradation of imidacloprid and acetamiprid in tea (Camellia sinensis) infusion by ultraviolet light irradiation

The degradation of imidacloprid and acetamiprid in tea infusion by ultraviolet (UV) light irradiation was investigated in this study. Results showed that the influence of UV light irradiation on the quality of tea infusion was controllable and UV light irradiation was effective on the degradation of both pesticides. The maximum removal rates were 75.2% for imidacloprid and 17.6% for acetamiprid after irradiation (650 µW/cm, 2 120 min). The degradation of both pesticides followed the first-order kinetics model. Three degradation products were identified for imidacloprid and one for acetamiprid based on liquid chromatography-tandem mass spectrometry analysis. The degradation pathway of imidacloprid involved in the cleavage of C–C bond with the loss of nitro group followed by the hydrogenation, oxidation and hydrolysis, while the degradation of acetamiprid involved in the oxidation at the chlorine atom with the bonding of C atoms at positions 1 and 4 on the pyridine ring. Simultaneously, the toxicity of both pesticides was mitigated by UV light irradiation according to LO2 cell toxicity evaluation. The study provided a low-cost and effective way to reduce imidacloprid and acetamiprid from tea infusion, and it has the potential to be applied to the ready-to drink tea beverage production in industrial scale.

Identification of new oxospiro chromane quinoline-carboxylate antimalarials that arrest parasite growth at ring stage

Malaria still threatens half the globe population despite successful Artemisinin-based combination therapy. One of the reasons for our inability to eradicate malaria is the emergence of resistance to current antimalarials. Thus, there is a need to develop new antimalarials targeting Plasmodium proteins. The present study reported the design and synthesis of 4, 6 and 7-substituted quinoline-3-carboxylates 9(a–o) and carboxylic acids 10(a–b) for the inhibition of Plasmodium N-Myristoyltransferases (NMTs) using computational biology tools followed by chemical synthesis and functional analysis. The designed compounds exhibited a glide score of −9.241 to −6.960 kcal/mol for PvNMT and −7.538 kcal/mol for PfNMT model proteins. Development of the synthesized compounds was established via NMR, HRMS and single crystal X-ray diffraction study. The synthesized compounds were evaluated for their in vitro antimalarial efficacy against CQ-sensitive Pf3D7 and CQ-resistant PfINDO lines followed by cell toxicity evaluation. In silico results highlighted the compound ethyl 6-methyl-4-(naphthalen-2-yloxy)quinoline-3-carboxylate (9a) as a promising inhibitor with a glide score of −9.084 kcal/mol for PvNMT and −6.975 kcal/mol for PfNMT with IC50 values of 6.58 µM for Pf3D7 line. Furthermore, compounds 9n and 9o exhibited excellent anti-plasmodial activity (Pf3D7 IC50 = 3.96, 6.71 µM, and PfINDO IC50 = 6.38, 2.8 µM, respectively). The conformational stability of 9a with the active site of the target protein was analyzed through MD simulation and was found concordance with in vitro results. Thus, our study provides scaffolds for the development of potent antimalarials targeting both Plasmodium vivax and Plasmodium falciparum. Communicated by Ramaswamy H. Sarma

Anti-parasitic effects of resveratrol on protoscolices and hydatid cyst layers

The main goal of the current study was to evaluate the effectiveness of resveratrol (RESV) on protoscolices and hydatid cysts of Echinococcus granolosus. Echinococcus granolosus protoscolices and hydatid cyst were exposed to RPMI, DMSO, formalin, mebendazole, and different concentrations of RESV in vitro. Then, viability, GGT, and caspase-3 activity of protoscolices were evaluated using light microscopy, colorimetric, and enzymatic assay, respectively. Tissue changes and expression of caspase-3 apoptosis were analyzed on the hydatid cyst wall by histologic and immunohistochemistry methods. The cell toxicity effect of RESV was evaluated on mouse PBMCs by Annexin V-FITC assay. The RESV-treated protoscolices showed loss of viability, increased gamma-glutamyl transpeptidase, and caspase-3 activity with significant differences compared to all control groups (P < 0.05). Dose and time dependence of mortality, GGT, and caspase-3 enzymatic activity was confirmed in the protoscolices of Echinococcus granulosus treated by RESV. Also, the tissue changes and apoptosis were prominent in RESV-treated hydatid cyst layers; however, tissue changes were only time-dependent, and RESV concentration had no apparent effect on tissue. In cell toxicity evaluation, RESV is safe without any significant apoptosis induction from 31.5 to 250 μg/ml; however, it was significant at 350 and 500 μg/ml in PBMCs.

In vitro release and cytotoxicity study of encapsulated sulfasalazine within LTSP micellar/liposomal and TSP micellar/niosomal nano-formulations

The micelles/liposome formulation for the first time has been constructed via thin-film hydration method containing soy lecithin (L), tween 80 (T), squalene (S), and polyvinyl alcohol (P) (LTSP nanoparticles). Similar ingredients except for lecithin were used for preparing micellar/niosomal vesicular SSZ nanoformulation (TSP nanoparticles). The percent drug loading and encapsulation efficiency of SSZ was 7.39% and 98.5 ± 0.3 % for the 7.5:100 (w/w) ratio of SSZ: total weight of LTSP, while the percent drug loading and encapsulation efficiency of SSZ was 4.7% and 62.85 ± 0.3 % in the TSP nanoformulation. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) results showed that both formulations formed spherical micelles and vesicles with globule sizes of 25 ± 1.2 nm and 100 ± 20.5 nm respectively. The cell toxicity evaluations showed that both LTSP and TSP nanoformulations without drug were nontoxic (at the range of this experiment) for Human Dermal Fibroblasts (HDF) as a normal cell line but SSZ loaded nanoformulation exhibited increased cell toxicity with half-maximal inhibitory concentration (IC50) of 940 µM for SSZ alone to near 240 µM for SSZ loaded nanoformulation (approximately four times). In vitro release experiments exhibited sustained release of SSZ from both nanoformulations. The LTSP micellar/liposomal and TSP micellar/niosomal nanoformulation for SSZ delivery can be considered as appropriate approaches for improving its bioavailability and probably they are good candidates for future clinical investigations.

New Antibacterial Peptides from the Freshwater Mollusk Pomacea poeyana (Pilsbry, 1927).

Antimicrobial peptides (AMPs) are biomolecules with antimicrobial activity against a broad group of pathogens. In the past few decades, AMPs have represented an important alternative for the treatment of infectious diseases. Their isolation from natural sources has been widely investigated. In this sense, mollusks are promising organisms for the identification of AMPs given that their immune system mainly relies on innate response. In this report, we characterized the peptide fraction of the Cuban freshwater snail Pomacea poeyana (Pilsbry, 1927) and identified 37 different peptides by nanoLC-ESI-MS-MS technology. From these peptide sequences, using bioinformatic prediction tools, we discovered two potential antimicrobial peptides named Pom-1 (KCAGSIAWAIGSGLFGGAKLIKIKKYIAELGGLQ) and Pom-2 (KEIERAGQRIRDAIISAAPAVETLAQAQKIIKGG). Database search revealed that Pom-1 is a fragment of Closticin 574 previously isolated from the bacteria Clostridium tyrobutyrium, and Pom-2 is a fragment of cecropin D-like peptide first isolated from Galleria mellonella hemolymph. These sequences were chemically synthesized and evaluated against different human pathogens. Interestingly, structural predictions of both peptides in the presence of micelles showed models that comprise two alpha helices joined by a short loop. The CD spectra analysis of Pom-1 and Pom-2 in water showed for both structures a high random coil content, a certain content of α-helix and a low β-sheet content. Like other described AMPs displaying a disordered structure in water, the peptides may adopt a helical conformation in presence of bacterial membranes. In antimicrobial assays, Pom-1 demonstrated high activity against the Gram-negative bacteria Pseudomonas aeruginosa and moderate activity against Klebsiella pneumoniae and Listeria monocytogenes. Neither of the two peptides showed antifungal action. Pom-1 moderately inhibits Zika Virus infection but slightly enhances HIV-1 infectivion in vitro. The evaluation of cell toxicity on primary human macrophages did not show toxicity on THP-1 cells, although slight overall toxicity was observed in high concentrations of Pom-1. We assume that both peptides may play a key role in innate defense of P. poeyana and represent promising antimicrobial candidates for humans.

Evaluation of cell toxicity and DNA and protein binding of green synthesized silver nanoparticles

Silver nanoparticles (AgNPs) were prepared by GREEN chemistry relying on the reduction of AgNO3 by phytochemicals present in black tea extract. AgNPs were fully characterized by transmission electron microscopy (TEM), ultraviolet-visible spectroscopy ((UV–vis)), X-ray diffraction (XRD) and energy dispersive absorption spectroscopy (EDS). The synthesized AgNPs induced a decrease of the cell viability in a dose-dependent manner with a low IC50 (0.5 ± 0.1 μM) for an ovarian carcinoma cell line (A2780) compared to primary human fibroblasts (IC50 5.0 ± 0.1 μM). The DNA binding capability of CT (calf thymus) DNA was investigated using electronic absorption and fluorescence spectroscopies, circular dichroism and viscosity titration methods. Additionally, the AgNPs strongly quench the intrinsic fluorescence of BSA, as determined by synchronous fluorescence spectra.

Development of essential oils as skin permeation enhancers: penetration enhancement effect and mechanism of action

Context: Essential oils (EOs) have shown the potential to reversibly overcome the stratum corneum (SC) barrier to enhance the skin permeation of drugs. Objective: The effectiveness of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, and clove oils were investigated for the capacity and mechanism to promote skin penetration of ibuprofen. Materials and methods: Skin permeation studies of ibuprofen across rat abdominal skin with the presence of 3% w/v EOs were carried out; samples were withdrawn from the receptor compartment at 8, 10, 22, 24, 26, 28, 32, 36, and 48 h and analyzed for ibuprofen content by the HPLC method. The mechanisms of penetration enhancement of EOs were further evaluated by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis and determination of the properties of EOs. Moreover, the toxicities of EOs on skin cells were also measured. Results: The enhancement ratio (ER) values of turpentine, Angelica, chuanxiong, Cyperus, cinnamon, clove oils and azone were determined to be 2.23, 1.83, 2.60, 2.49, 2.63 and 1.97, respectively. Revealed by ATR-FTIR analysis, a linear relationship (r = 0.9045) was found between the ER values and the total of the shift of peak position of SC lipids. Furthermore, the results of HaCaT skin cell toxicity evaluation revealed that the natural EOs possessed relatively lower skin irritation potential. Conclusion: Compared with azone, the investigated EOs possess significantly higher penetration enhancement effect and lower skin toxicity. EOs can promote the skin permeation of ibuprofen mainly by disturbing rather than extracting the SC lipids.

Improvement of Anti-inflammatory and Antibacterial Effects of Combined Crude Drug Extracts Including Barafu on Atopic Dermatitis

Introduction: Long-term use of steroid as a cure for atopic dermatitis can cause side effects. Therefore, there has been research on commercialized use of natural combined crude drug extracts as medicines recently. Against this backdrop, the study aims to investigate the clinical, anti-inflammatory, anti-bacterial effects of combined crude drug extracts including Barafu on atopic dermatitis patients. Methods: The combined crude drug extracts used for the study include various plant bodies such as Barafu, Phellinus linteus (SANG HWANG Mushroom) and formulated into a cream product. Analysis of anti-inflammatory effect was conducted using cell toxicity evaluation by MTT assay, and gene expression related to anti-inflammatory was measured with primers of TNF (tumor necrosis factor)-α, COX (cyclooxygenase)-2 and IL (interleukin)-1β. Also, anti-bacterial activity was measured by conducting antibacterial activity for Staphylococcus aureus. Clinical effectivity evaluation was conducted through SCORing Atopic Dermatitis (SCORAD) index and patients' global assessment of clinical response, and itching sensation was assessed with 10 cm visual analogue score. Results: As a result of analysis on the anti-inflammatory effect, Ethanol (EtOH) solvent extract had little effect on the expression of inflammation genes, while Ethyl acetate (EA) and Methylene chloride (MC) solvent extracts showed decreased expression of TNF-α, COX-2 and IL-1β gene, showing anti-inflammatory effect. As for antibacterial effect, combined plant extract containing Barafu showed improved anti-bacterial activity compared to other natural single plant extracts. Also, the clinical symptom evaluation showed significant decrease in objective SCORAD index before and after treatment. Conclusion: Based on the results, it was revealed that combined plant extracts and the application products including Barafu had anti-inflammatory and anti-bacterial effects and improvement of itchiness for atopic dermatitis patients. Therefore, follow-up studies on moisturizing effect and clinical stability for patients are expected to be contributable for atopic dermatitis medicines.

Next generation carbon nanoparticles for efficient gene therapy.

In a pursuit to develop a commercially exploitable and traceable gene delivery vehicle, here, we develop next generation carbon nanoparticle-DNA complex (CNPLex). CNPLexes were used to transfect green fluorescent protein (GFP) reporter gene containing plasmid DNA (pDNA) pEGFP-N1 targeting breast cancer cells MCF-7 and MDA-MB231. Prepared CNPs were optimized for particle size, surface potential, polymer surface decoration, absorbance efficiency, fluorescence efficiency, IR spectroscopic signatures, and DNA loading and release efficiencies. Rigorous biophysical methods were employed to determine the variations in physicochemical properties of CNPs after surface decoration with polymers followed by complexation with pDNA. Optimized CNPLexes were used to deliver pEGFP-N1 plasmid and efficiency of GFP was followed by fluorescence microscopy and quantified by flow assisted cell sorting. Lipofectamine2000 was used as positive control according to manufacturer's protocol and found to be comparative in transfection efficiency with one of our novel formulations. Further evaluation of cell toxicity and cell viability was performed by LDH activity and MTT assay, respectively. It was found that cell toxicity furnished by polymer decorated carbon nanoparticles was significantly low compared to the parent polymer (polyethylenimine, PEI). Similarly cell viability was found to be much higher with CNPLexes compared to PEI alone. This established the developed particles as better transfecting agents for reporter gene plasmid pEGFP-N1 compared to PEI and showed similar efficacy to one of the best known commercial transfection agents Liofectamine2000 in breast cancer cells MCF-7 and MDA-MB231.

Evaluation of effect of galvanic corrosion between nickel-chromium metal and titanium on ion release and cell toxicity.

PURPOSEThe purpose of this study was to evaluate cell toxicity due to ion release caused by galvanic corrosion as a result of contact between base metal and titanium.MATERIALS AND METHODSIt was hypothesized that Nickel (Ni)-Chromium (Cr) alloys with different compositions possess different corrosion resistances when contacted with titanium abutment, and therefore in this study, specimens (10×10×1.5 mm) were fabricated using commercial pure titanium and 3 different types of Ni-Cr alloys (T3, Tilite, Bella bond plus) commonly used for metal ceramic restorations. The specimens were divided into 6 groups according to the composition of Ni-Cr alloy and contact with titanium. The experimental groups were in direct contact with titanium and the control groups were not. After the samples were immersed in the culture medium - Dulbecco's modified Eagle's medium[DMEM] for 48 hours, the released metal ions were detected using inductively coupled plasma mass spectrometer (ICP-MS) and analyzed by the Kruskal-Wallis and Mann-Whitney test (P<.05). Mouse L-929 fibroblast cells were used for cell toxicity evaluation. The cell toxicity of specimens was measured by the 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) test. Results of MTT assay were statistically analyzed by the two-way ANOVA test (P<.05). Post-hoc multiple comparisons were conducted using Tukey's tests.RESULTSThe amount of metal ions released by galvanic corrosion due to contact between the base metal alloy and titanium was increased in all of the specimens. In the cytotoxicity test, the two-way ANOVA showed a significant effect of the alloy type and galvanic corrosion for cytotoxicity (P<.001). The relative cell growth rate (RGR) was decreased further on the groups in contact with titanium (P<.05).CONCLUSIONThe release of metal ions was increased by galvanic corrosion due to contact between base metal and titanium, and it can cause adverse effects on the tissue around the implant by inducing cytotoxicity.

Synthesis of amphiphilic copolymers containing zwitterionic sulfobetaine as pH and redox responsive drug carriers

Amphiphilic poly(ɛ-caprolactone)-SS-poly(N,N-diethylaminoethyl methacrylate)-r-poly(N-(3-sulfopropyl)-N-methacrylate-N,N-diethylammonium-betaine) (PCL-SS-PDEASB) was designed and synthesized successfully. pH and redox dually responsive micelles were prepared based on the obtained copolymers, with zwitterionic sulfobetaines as hydrophilic shell, DEA as pH sensitive content and disulfide as redox responsive linkage. The micelle diameters were all less than 200nm and the micelle diameter distributions were narrow. These micelles could be triggered by pH and redox condition. The drug release from the drug-loaded micelles displayed fastest under simultaneously acidic and reductive conditions. Results of in vitro cell toxicity evaluation showed that introduction of sulfobetaines could greatly decrease the toxicity of poly(ɛ-caprolactone)-SS-poly(N,N-diethylaminoethyl methacrylate) (PCL-SS-PDEA) micelles. DOX-loaded PCL-SS-PDEASB micelles showed higher efficiency to kill HeLa cells than DOX-loaded PCL-PDEASB micelles. Half inhibitory concentration (IC50) of DOX-loaded PCL-SS-PDEASB micelles decreased with the content of sulfobetaines increasing and was even closer to that of DOX·HCl. Thus, the pH and redox dually responsive biodegradable micelles generated by PCL-SS-PDEASB may be potential smart drug carriers for tumor targeted delivery.

Gadolinium-Loaded Chitosan Nanoparticles as Magnetic Resonance Imaging Contrast Agents for the Diagnosis of Tumor

The aim of our study was to prepare gadolinium loaded chitosan nanoparticles (Gd-CSNPs) for magnetic resonance imaging (MRI). The chitosan nanoparticles (CSNPs) were prepared by ionic gelation method with sodium tripolyphosphate. The Gd ions were conjugated to the surface of CSNPs through diethylenetriamine pentaacetic acid (DTPA) using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to obtain Gd-CSNPs. The physicochemical properties of CSNPs and Gd-CSNPs were measured by transmission electron microscope, dynamic light scattering and inductively coupled plasma optical emission spectroscopy, respectively. The cell toxicity evaluation was performed in mouse B16 cells by MTT assay. The T1-weighed magnetic resonance images were measured by a 3.0 T Sigma scanner. The morphologies of the CSNPs and Gd-CSNPs were spherical or ellipsoidal in shape. The mean sizes of the CSNPs and Gd-CSNPs were 110.9 +/- 6.8 nm and 153.0 +/- 7.5 nm, respectively. The zeta potentials of the CSNPs and Gd-CSNPs were 22.30 +/- 0.77 mV and 13.91 +/- 4.26 mV, respectively. The relaxation rates of Gd-CSNPs and Magnevist were 7.509 mM(-1) x s(-1) and 3.052 mM(-1) x s(-1), respectively. The Gd-CSNPs exhibited high T1 relaxivity and no obvious cytotoxicity was observed under the experimental concentrations in mouse B16 melanoma cells. These results indicated that the Gd-CSNPs had great potential as MRI contrast agents for the early diagnosis of tumor.

Local Neurotoxicity and Myotoxicity Evaluation of Cyclodextrin Complexes of Bupivacaine and Ropivacaine

Bupivacaine (BVC) and ropivacaine (RVC) are local anesthetics widely used in surgical procedures. In previous studies, inclusion complexes of BVC or RVC in hydroxypropyl-β-cyclodextrin (HP-β-CD) increased differential nervous blockade, compared to the plain anesthetic solutions. In this study we evaluated the local neural and muscular toxicity of these new formulations containing 0.5% BVC or RVC complexed with HP-β-CD (BVC(HP-β-CD) and RVC(HP-β-CD)). Schwann cell viability was assessed by determination of mitochondrial dehydrogenase activity, and histopathological evaluation of the rat sciatic nerve was used to identify local neurotoxic effects (48 hours and 7 days after the treatments). Evaluations of serum creatine kinase levels and the histopathology of rat gastrocnemius muscle (48 hours after treatment) were also performed. Schwann cell toxicity evaluations revealed no significant differences between complexed and plain local anesthetic formulations. However, use of the complexed local anesthetics reduced serum creatine kinase levels 5.5-fold, relative to the plain formulations. The differences were significant at P < 0.05 (BVC) and P < 0.01 (RVC). The histopathological muscle evaluation showed that differences between groups treated with local anesthetics (BVC or RVC) and their respective complexed formulations (BVC(HP-β-CD) or RVC(HP-β-CD)) were significant (P < 0.05). We concluded that the new formulations presented a lower myotoxicity and a similar cytotoxic effect when compared to plain local anesthetic solutions.

ChemInform Abstract: Synthesis, anti‐HBV Activity and Renal Cell Toxicity Evaluation of Mixed Phosphonate Prodrugs of Adefovir.

AbstractA series of phosphonate ester prodrugs (I) of adefovir incorporating L‐amino (thio)acid and non‐steroidal anti‐inflammatory drug (NSAID) moieties is synthesized and evaluated for their anti‐HBV and renal cell toxicity in HepG2 2.2.15 and HK‐2 cells, respectively.

Synthesis, anti-HBV activity and renal cell toxicity evaluation of mixed phosphonate prodrugs of adefovir

A series of phosphonate ester prodrugs of adefovir incorporating l-amino (thio)acid and non-steroidal anti-inflammatory drug (NSAID) moieties were synthesized and their anti-HBV activity and renal cell toxicity were evaluated in HepG2 2.2.15 and HK-2 cells respectively. Bioactivity evaluation results revealed that this kind of adefovir prodrug have lower renal cell toxicity than adefovir dipivoxil. Compounds 8a and 8b, incorporating the NSAID ketoprofen and the l-amino acid (Val or Ile) structural fragments, exhibited more potent anti-HBV activity than adefovir dipivoxil with IC50 = 0.51 and 0.73 μM, SI = 1697.64 and 881.92 respectively. In vitro stability studies showed that the synthesized prodrugs have higher chemical and plasma stability than the positive control adefovir dipivoxil.

Anionic linear-globular dendrimers: biocompatible hybrid materials with potential uses in nanomedicine

The use of dendrimers as nano-sized excipients/vectors in biological and pharmaceutical systems is dependent on the investigation of their toxicological profiles in biological media. In this study, a series of mechanistic in vitro structure-associated cell toxicity evaluations was performed on the two generations of an anionic linear-globular dendrimer G1 and G2 (where PEG is the core, and citric acid is the periphery) each of which has a different size, charge, and MW. In vitro cytotoxicity behavior of the dendrimers with the methods like crystal violet staining, methyl thiazolyl tetrazolium (MTT), and lactate dehydrogenase (LDH) assays was analyzed. The cell death mechanisms (apoptosis-necrosis) induced by the dendrimers were also evaluated in HT1080 cell line. The impact of the dendrimers on the release of the pro-inflammatory cytokines like TNF-alpha (tumor necrosis factor alpha) and IL1-beta (interleukin 1 beta) was assessed in THP-1 cell line. Hemolysis assay and coagulation studies such as PT (prothrombin time) and APTT (activated partial thromboplastin time) on human blood samples were conducted to examine the interactions of the dendrimers with such bio-environments. The results of cell cytotoxicity experiments and the amounts of IL1-beta and TNF-alpha secretions from THP-1 cell line were consistent with the hemoglobin release from the erythrocytes and the results gained from the coagulation studies. In fact, no significant harmful effect was observed for the dendrimers up to the concentration of 0.5 mg/ml. Both apoptosis and necrosis were ascribed to cell death. The G1 with more flexibility, less negative charge, and greater poly dispersity in size versus the G2 displayed more toxicity than the G2 at the concentration of 1 mg/ml and above in most of the experiments. As a whole, these results suggest a biocompatible range for these hybrid structures up to the concentration of 0.5 mg/ml. Therefore, the potentiality for these structures to be employed in the different and numerous realms of nanomedicine will be very great.

Characterization of Surface Oxide Films and Cell Toxicity Evaluations with a Quenched Titanium Surface

This study characterizes the surface of the oxide film that forms on titanium metal through the use of thermal and quenching treatments in cold water and investigates the effects of the surface characteristics and cellular interactions of a modified titanium surface. A range of sample groups were prepared in heat treatments of pure titanium at 600°C, 700°C, 800°C, 900°C, and 1000°C and subsequent quenching in cold water. The surface topography, roughness, crystallite size and crystal intensity were found to depend on the heating temperature. An increased surface roughness was observed with increases in the heating temperature and the quenching. The surface roughness was in the range of 0.15 μm–1.07 μm. In vitro cell responses were evaluated with mouse osteoblast MC3T3 cells in terms of cell proliferation and differentiation. MTT assays showed an increase in the living cell density and proliferation upon heating and quenching the titanium surface. The results of this study indicate that the cell toxicity was sensitive to the surface roughness and that it decreased as the roughness of the Ti increased.

Conductive polymer as a controlled microenvironment for the potentiometric high-throughput evaluation of ionic liquid cell toxicity

This paper presents both biological and potentiometric evaluations of the cell toxicity of a widely used ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF(4)), to Chinese hamster lung fibroblast cells (V79 cell line). The innovative potentiometric study takes advantage of the unique properties of conductive polymer polypyrrole (PPY) for the potentiometric evaluation of cell toxicity of [bmim]BF(4) to the V79 cells in a real-time, noninvasive and high-throughput manner. The conductive polymer PPY provides a controlled microenvironment that allows the quantitative release of the anions of the ionic liquids into the cells being monitored in real time and noninvasively. Parallel biological assay results showed that V79 cells exposed to [bmim]BF(4) usually grew in clusters, and that many small vacuoles could be seen in the cytoplasm. At the 24th hour after the V79 cells had been exposed to the ionic liquid (IL), the half inhibition concentration (EC(50)) of [bmim]BF(4) was around 5 mM. From a cell cycle study performed using a FACScan flow cytometer, it was found that the V79 cells could be partially locked to the G(1) phase by [bmim]BF(4), which extended the doubling time for cell growth. Comparing with the EC(50) values of cadmium chloride and mercury chloride, [bmim]BF(4) is not very toxic, but it may have a long-term toxic effect on mammalian cells. Compared to traditional biological in vitro assays, the use of a conductive polymer substrate in combination with a potentiometric sensor array is much more sensitive, faster, and enables a simpler evaluation of chemical cell toxicity. Additionally, it simplifies the study of the reversibility of cell toxicity, i.e., cell recovery, because there is no need to refresh the culture medium since a finite amount of chemicals can be doped and released. We found that the cytotoxicity of [bmim]BF(4) at a concentration of less than 6 mM was reversible for the V79 cell line, because cell morphology and proliferation rate returned to normal after the removal of the IL from the culture medium. This finding suggests that the IL [bmim]BF(4) could be used as a tool to control mammalian cell proliferation rate.

Construction of antibacterial multilayer films containing nanosilver via layer‐by‐layer assembly of heparin and chitosan‐silver ions complex

Antibacterial multilayer films containing nanosilver were prepared via layer-by-layer fashion. PET film was aminolyzed with 1,6-hexanediamine to introduce amino groups on PET film surface; chitosan-silver nitrate complex and heparin were alternately deposited onto an aminolyzed PET film surface, and subsequently, the silver ions within the multilayer films were reduced with ascorbic acid to form silver nanoparticles. UV-visible spectroscopy and transmission electron microscopy confirmed the formation of well-dispersed nanosilver particles with sizes (10-40 nm) that depended on the initial concentration of silver ions in chitosan solution and the pH of ascorbic acid solution. The chitosan/heparin multilayer films were possessed of bactericidal effect on Escherichia coli (E. coli), and this antibacterial effect could be significantly enhanced by the incorporation of silver nanoparticles into the multilayer films. The multilayer films containing nanosilver were not only effective as antibacterial but also as anticoagulant coating. And cell toxicity evaluation suggested that the multilayer films containing nanosilver did not show any cytotoxicity. The multilayer films containing nanosilver may have good potentials for surface modification of medical devices, especially for cardiovascular implants.