In vitro cytotoxicity evaluation of biomedical nanoparticles and their extracts

Cytotoxicity Evaluation of Turmeric Extract Incorporated Oil-in-Water Nanoemulsion

To overcome the drawbacks of conventional drug delivery system, nanoemulsion have been developed as an advanced form for improving the delivery of active ingredients. However, safety evaluation is crucial during the development stage before the commercialization. Therefore, the aim of this study was to evaluate the cytotoxicity of two types of newly developed nanoemulsions. Turmeric extract-loaded nanoemulsion powder-10.6 (TE-NEP-10.6, high content of artificial surfactant Tween 80), which forms the optimal nanoemulsion, and the TE-NEP-8.6 made by increasing the content of natural emulsifier (lecithin) to reduce the potential toxicity of nanoemulsion were cultured with various cells (NIH3T3, H9C2, HepG2, hCPC, and hEPC) and the changes of each cell were observed followed by nanoemulsion treatment. As a result, the two nanoemulsions (TE-NEP-10.6 and TE-NEP-8.6) did not show significant difference in cell viability. In the case of cell line (NIH3T3, H9C2, and HepG2), toxicity was not observed at an experimental concentration of less than 1 mg/mL, however, the cell survival rate decreased in a concentration dependent manner in the case of primary cultured cells. These results from our study can be used as a basic data to confirm the cell type dependent toxicity of nanoemulsion.

Investigation of the cytotoxicity of thermoplastic denture base resins

PURPOSE

The purpose of this study was to investigate the in vitro cytotoxicity of thermoplastic denture base resins and to identify the possible adverse effects of these resins on oral keratinocytes in response to hot water/food intake.

MATERIALS AND METHODS

Six dental thermoplastic resin materials were evaluated: three polyamide materials (Smile tone, ST; Valplast, VP; and Luciton FRS, LF), two acrylic materials (Acrytone, AT; and Acryshot, AS), and one polypropylene resin material (Unigum, UG). One heat-polymerized acrylic resin (Vertex RS, RS) was chosen for comparison. After obtaining extracts from specimens of the denture resin materials (Φ=10 mm and d=2 mm) under different extraction conditions (37℃ for 24 hours, 70℃ for 24 hours, and 121℃ for 1 hour), the extracts (50%) or serial dilutions (25%, 12.5%, and 6.25%) in distilled water were co-cultured for 24 hours with immortalized human oral keratinocytes (IHOKs) or mouse fibroblasts (L929s) for the cytotoxicity assay described in ISO 10993.

RESULTS

Greater than 70% viability was detected under all test conditions. Significantly lower IHOK and L929 viability was detected in the 50% extract from the VP (70℃) and AT (121℃) samples (P<.05), but only L929 showed reduced viability in the 50% and 25% extract from LF (37℃) (P<.05).

CONCLUSION

Extracts obtained from six materials under different extraction conditions (37℃, 70℃, and 121℃) did not exhibit severe cytotoxicity (less than 70% viability), although their potential risk to oral mucosa at high temperatures should not be ignored.

Sublethal effects of CuO nanoparticles on Mozambique tilapia (Oreochromis mossambicus) are modulated by environmental salinity

The increasing use of manufactured nanoparticles (NP) in different applications has triggered the need to understand their putative ecotoxicological effects in the environment. Copper oxide nanoparticles (CuO NP) are toxic, and induce oxidative stress and other pathophysiological conditions. The unique properties of NP can change depending on the characteristics of the media they are suspended in, altering the impact on their toxicity to aquatic organisms in different environments. Here, Mozambique tilapia (O. mossambicus) were exposed to flame synthesized CuO NP (0.5 and 5 mg·L⁻¹) in two environmental contexts: (a) constant freshwater (FW) and (b) stepwise increase in environmental salinity (SW). Sublethal effects of CuO NP were monitored and used to dermine exposure endpoints. Fish exposed to 5 mg·L⁻¹ CuO in SW showed an opercular ventilation rate increase, whereas fish exposed to 5 mg·L⁻¹ in FW showed a milder response. Different effects of CuO NP on antioxidant enzyme activities, accumulation of transcripts for metal-responsive genes, GSH∶GSSG ratio, and Cu content in fish gill and liver also demonstrate that additive osmotic stress modulates CuO NP toxicity. We conclude that the toxicity of CuO NP depends on the particular environmental context and that salinity is an important factor for modulating NP toxicity in fish.

Effect of Silver Coating on Barium Titanium Oxide Nanoparticle Toxicity

Nanoparticles are presently being studied for optical and biomedical applications such as medical imaging and drug delivery. Nanoparticles impact the cellular environment due to many variables such as size, shape, and composition. How these factors affect cell viability is not fully understood. The purpose of this study is to test the toxicity effects of silver coating (Ag@) Barium Titanium Oxide (BaTiO₃) nanoparticles on Rhesus Monkey Retinal Endothelial cells (RhREC's) in culture. The addition of silver to the nanoparticles increases their nonlinear optical properties significantly, making the Ag@BaTiO₃ nanoparticles good candidates for nonlinear microscopy contrast agents. We hypothesize that by silver coating nanoparticles, there will be an increase in cell viability at higher concentrations when compared to non-silver coated nanoparticles. RhREC's were treated with BaTiO₃ and Ag@BaTiO₃ at concentrations of 0, 1.0, 10.0, and 100µg/ml for 24 hours at 37°C + 5%CO₂. After 24 hour incubation with respective nanoparticles, cell viability was determined using the trypan blue dye-exclusion method. Treatment with 0, 1.0 and 10.0µg/ml of Ag@BaTiO₃ had minimal effect on cell viability, with 90% viable cells remaining at the end of the 24 hours treatment period. However, cells treated with 100µg/ml of Ag@BaTiO₃ resulted in a decrease to 51% viable cells. Comparatively, cells treated with 0, 1.0 and 10µg/ml of BaTiO₃ had no significant effect on cell viability (90% viable cells after treatment) while the 100µg/ml treatment resulted in a decrease to 29% viable cells. These results show that silver coating of BaTiO₃ nanoparticles has a protective effect on cellular toxicity at high concentrations.

Assembly and targeting of liposomal nanoparticles encapsulating quantum dots

Quantum dots (QDs) are attracting intense interest as fluorescence labeling agents for biomedical imaging because biocompatible coatings and relatively nontoxic rare earth metal QDs have emerged as possible options. QD photoemissions are bright, of narrow wavelength range, and very stable. We sought to encapsulate QDs within targeted PEGylated liposomes to reduce their propensity for liver uptake and to amplify the already strong QD emission signal. A novel lipid-QD conjugate initialized a process by which lipids in solution coalesced around the QDs. The liposomal structure was confirmed with size measurements, SEM, and IR spectroscopy. PEGylated QD liposomes injected into a xenograft tumor model largely cleared from the body within 24 h. Residual liver labeling was low. Targeted QD liposomes exhibited robust tumor labeling compared with controls. This study highlights the potential of these near IR emitting QD liposomes for preclinical/clinical applications.

Mitigation of quantum dot cytotoxicity by microencapsulation

When CdSe/ZnS-polyethyleneimine (PEI) quantum dots (QDs) are microencapsulated in polymeric microcapsules, human fibroblasts are protected from acute cytotoxic effects. Differences in cellular morphology, uptake, and viability were assessed after treatment with either microencapsulated or unencapsulated dots. Specifically, QDs contained in microcapsules terminated with polyethylene glycol (PEG) mitigate contact with and uptake by cells, thus providing a tool to retain particle luminescence for applications such as extracellular sensing and imaging. The microcapsule serves as the “first line of defense” for containing the QDs. This enables the individual QD coating to be designed primarily to enhance the function of the biosensor.

Gadolinium oxide ultranarrow nanorods as multimodal contrast agents for optical and magnetic resonance imaging

We demonstrate a simple synthetic strategy for the fabrication of single-phase rare earth (RE) doped gadolinium oxide (Gd(2)O(3):RE where RE = terbium (Tb), ytterbium (Yb), and erbium (Er)) nanorods (NRs) as multimodal imaging probes. The NRs are ultranarrow and exhibit both emission and magnetic characteristics. The Tb-doped and Yb/Er-codoped Gd(2)O(3) NRs exhibit down- and up-conversion fluorescence respectively, and also exhibit paramagnetism. Importantly, these codoped NRs possess excellent magnetic characteristics, as shown in their longitudinal relaxation time (T1) -weighted image contrast, which is closer to that of commercial Gadovist for magnetic resonance imaging (MRI) applications. This property opens up new avenues in the development of contrast agents.