Table 4.
In vitro toxicity studies of intestinal NP exposures
| Author | NP | Size | Dose | Model | Endpoint(s) | Effect/conclusion |
|---|---|---|---|---|---|---|
| #(Bouwmeester et al. 2011) | Ag | 20–113 nm | 5–50 µg/mL; 4 and 24 h | Caco-2/M cell co-culture | WST-1, TEER, microarray | No toxicity; significant changes in gene expression due to ionic Ag |
| (Lamb et al., 2010) | Ag | Not reported | 1–10 µg/mL; 24 h | Caco-2 (MDR1.C) | MultiTox-Fluor Multiplex Cytotoxicity assay; MDR1 reporter induction response to drugs | LD50 5 µg/mL; <1 µg/mL had no effect on drug metabolism |
| #(Gaiser et al., 2012) | Ag and CeO2 | 35 nm (Ag) and <25 nm (CeO−) | 3.125 and 31.25 µg/cm2; and 24 h | Caco-2 | LDH | Uptake but no toxicity |
| (Alkilany et al., 2009) | Au nanorod (coated) | AR 4.1 | 0.4 nM; 4 da | HT29 | MTT, cell count | Cytotoxicity observed due to surfactant coating; not Au nanorods |
| (Pelka et al., 2009) | Pt | < 20, < 100, > 100 nm | 0.0001–1,000 ng/cm2; 3 and 24 h | HT29 | ROS, GSH, TBET, Nrf-2 translocation, comet assay | ↓ GSH level; impaired DNA integrity; no ROS; no viability effect; no Nrf-2 translocation |
| (Rodriguez-Luccioni et al., 2011) | FeO (magnetic) | 72 nm | 0.3–1.5 mg/mL; 24 and 48 h | Caco-2 | CellTiter-Blue™, ApoPercentage assay | Cytotoxicity and apoptosis with exposure + magnetic field-induced hyperthermia |
| #(Zhang et al., 2010b) | Hematite (αFe2O3) | 26, 53, 76 and 98 nm | 100, 200 and 300 mg/L; 5, 15, 25 and 45 min | Caco-2 | SEM, TEER, immunocytochemistry | ↓ TEER; dynamic reorganisation and detachment of microvilli, cell junctions disrupted |
| (Hildebrand et al., 2010) | Magnetite (Fe3O4) and palladium/magnetite | 255 nm and 307 nm | 5, 10 and 25 µg/mL; 1 h–3 da | Caco-2 | AlamarBlue/CFDA-AM/Neutral red, ROS | Minor viability effects; minor membrane and lysosomal integrity ↓; no ↑ ROS |
| #(Piret et al., 2012) | CuO | 12 and 50–80 nm | 5–100 µg/ml; 24 and 120 h | Caco-2 | TEER, MTS, qPCR, TaqMan PCR array, IL-8 | Monolayer integrity disrupted; cytotoxicity; ↑ pro-inflammatory cytokine/chemokine gene expression; Cu++ toxicity implicated |
| #(Koeneman et al., 2010) | TiO2 | < 40 nm | 1–1,000 µg/mL; 1–24 h | Caco-2 | TEER, TEM and confocal imaging | No effect on monolayer integrity; tight junctions; cell death; non-lethal effects on microvilli and intracellular Ca++ |
| (Gehrke et al., 2012) | SiO2 | 12, 40 and 200 nm | 0.3–156.3 µg/cm2; 24, 48, 72 h | HT29 | SRB & WST-1 assays, LDH, ROS, GSH, Comet assay, qPCR | Cytotoxicity depends on concentration, size, and FCS content; ↓GSH; no ↑ROS; interference with MAPK/ERK1/2 and Nrf2/ARE signalling |
| (De Berardis et al., 2010) | ZnO | 50–70 nm | 10, 20 and 40 µg/cm2; 24 h | LoVo | WST-1, apoptosis, ROS, GSH, TBET, SEM, cytokine ELISA | ↓ viability; ↑ ROS; ↓ GSH; IL-8 release; may be due to ionic Zn |
| (Moos et al., 2010) | nZnO and mZnO | 20–60 nm and 100–1,000 nm | 1–100 µg/mL; 24 h | RKO | Cell Counting Kit-8, propidium iodide exclusion, Vybrant apoptosis, MitoProbe JC-1, MitoSOX | Cytotoxicity involving apoptotic pathways, dependent on NP contact with cell; disruption of mitochondrial potential; ↑ ROS |
| (Moos et al., 2011) | SiO2, TiO2, ZnO, Fe2O3 | 10 nm, 5 nm, 8–10 nm, 3 nm | 1–100 µg/cm2; 4 and 24 h | RKO, Caco-2 | Cell Counting Kit-8, functional genomics via microarray | ZnO maximally toxic; TiO2 minimally toxic; changes in metal metabolism; chaperonin; and protein folding gene expression |
| (Gerloff et al., 2009) | TiO2, SiO2, MgO, ZnO | 8–80 nm | 20–80 µg/cm2; 4 and 24 h | Caco-2 | Comet assay, LDH, WST-1, GSH depletion | Cytotoxicity & DNA damage (ZnO) |
| (Rhoads et al., 2010) | VO nanotubes | 15–100 nm × 500 nm | 0.1–0.5 mg/mL; 4–24 h | Caco-2 | Neutral red assay | Nanotubes caused significant loss in viability |
| (Wang et al., 2008) | CdSe QD | 1.4–2.5 nm | 2–200 pM; 24 h | Caco-2 | MTT, cell attachment assay | Cytotoxicity at 200 pM due to Cd++ |
| #(Koeneman et al., 2009) | CdTe QD | 15 nm and 500 nm aggregates | 0.01µg–1 mg/L; 24 h | Caco-2 | TEER | Disruption of monolayer and cell death at 0.1 mg/L; caused by the nano-sized QDs |
| #(Loretz and Bernkop-Schnurch, 2007) | chitosan/pDNA | 18.4–197.0 nm (hydro. diam) | 5 and 10 µg pDNA; 5–120 min | Caco-2 | TEER, LDH, MTT | Toxicity related to surface charge – cationic nanoparticles caused severe cytotoxic effects |
| (Kitchens et al., 2007) | PAMAM dendrimers | G2NH2, G4NH2, G1.5COOH, G3.5COOH | 0–1 mM, 2 h | Caco-2 | visualisation with TEM | Cationic surface groups on G4NH2 dendrimers disrupt membrane |
| (Bhattacharjee et al., 2012) | PEG tri-block copolymer | 45 nm | 0.1–400 µg/mL; 24 h | Caco-2 | MTT, ROS | (+) PNPs more cytotoxic and induced ↑ ROS than neutral and (−); surface charge-specific interaction of clathrin with (+) PNPs and caveolin receptors with (−) PNPs |
| #(Thubagere and Reinhard, 2010) | NH and COOH funct. polystyrene (FluoSpheres) | 20 and 40 nm | 0.3–6.6 nM; 4, 8, 12, and 16 h | Caco-2 | Live/Dead® cell assay, Vybrant apoptosis assay | Uptake efficiency and cytotoxicity higher for (−) charged and smaller PS; oxidative stress-mediated apoptosis of bystander cells |
| (Fröhlich et al., 2012) | Carboxyl polystyrene NP | 20–1,000 nm | 50–500 µg/mL; 4 and 24 h | Caco-2 | Neutral Red uptake, ATP content, MTS, WST-1, MTT, SRB, leucine uptake | Small size, greater toxicity; IC50 320 µg/mL |
| (Ruizendaal et al., 2009) | Si NP ((+), (−) and neutral charge) | 1.6 nm | 0–2.2 mg/L; 24 h | Caco-2 | MTT, BrdU assay, | (+) charged Si NPs are more cytotoxic than (−) charged Si NPs and require fetal calf serum in media |
| #(Jos et al., 2009) | SWCNT-COOH | 1.4 × 4–5 nm | 5–1,000 µg/mL; 24 h | Caco-2 | Neutral red uptake, MTS, TBET, LDH, | Toxic effects at concentrations > 100 µg/mL |
| (Kulamarva et al., 2008) | SWCNT-COOH-plasmid complex | NR | 0.5–2.0 µg/mL; 4–48 h | SW480 | MTS | ↓ cell viability at higher dose |
| #(Lai et al., 2012) | SWCNT-COOH, MWCNT-COOH, MWCNT-PVP | 0.8–1.2 × 0.1–1 µm 20–30 nm × 10–30 µm 20–30 nm × 10–30 µm | 500 pg/mL and 10 µg/mL; 48 h | Caco-2/HT29-MTX co-culture | XTT, LDH, ROS, proinflammatory cytokines, lucifer yellow flux, proteomics | No cytotoxicity; no irritation; barrier integrity normal; no ROS; significant NP- and dose-specific alterations in global protein expression and functional pathways |
| (Pelka et al., 2011) | SWCNT, CB | 1.8 × 500 nm, 14 nm (CB) | 0.05 ng/mL–0.2 µg/mL (SWCNT); 0.5 mg/mL (CB); 24, 48 and 72 h | HT29 | Comet assay, sulforhodamine B assay, WST-1, LDH, ROS, GSH, Nrf-2 translocation, micronuclei count | ↓ growth at 48 and 72 h; ↓ mitochondrial activity at 24 h; DNA damage; ↑ micronuclei; membrane integrity unaltered |
| (Chiaretti et al., 2008) | MWCNT | 110–170 nm × 5–9 µm | 1–100 µg/mL; 24 and 72 h | Caco-2 | Cell count | No toxicity |
| (Ponti et al., 2010) | MWCNT | 10 nm × 0.1–10 µm | 1, 10 and 100 µg/mL; 72 h | Caco-2 | Colony forming efficiency (CFE) assay | No cytotoxicity based on CFE |
| (Zhang et al., 2008) | MWCNT and phosphoryl choline | 10–30 nm × 5–15 µm | 40, 200 and 1,000 µg/mL; 48 h | Caco-2 | MTT, WST-1 | No toxicity |
Note:
#
studies in which fully differentiated intestinal cell monolayers were used.