Oral Toxicity of Indium in Rats: Single and 28‐Day Repeated Administration Studies

Lead-free Perovskite with Distorted [InX6]3- Octahedron Induced by Organic Cation and Enhanced PLQY by Sb Doping

In-based halide perovskites have attracted a lot of attention because of their unique broadband emission properties. Herein, a series of In-based hybrid perovskites of (H2MP)2InCl7·H2O (1), (H2EP)2InCl7·H2O (2), (H2MP)2InBr7·H2O (3), and (H2EP)2InBr7·H2O (4) were synthesized under the control of halogen ions and organic cations. 1, 2, and 4 exhibit obvious photoluminescence properties with peaks at 392, 442, and 652 nm, respectively. The effects of the different components on the crystal structure and photoluminescence properties are discussed by calculating the structural distortion of the [InX6]3- octahedron. The photoluminescence properties of 1 and 4 were significantly improved after Sb3+ doping with PLQY values of 57.12 and 41.53%. Finally, a white LED was successfully fabricated with the two doped compounds coated onto the 365 nm blue LED chip.

Oral trivalent bismuth ions decrease, and trivalent indium or ruthenium ions increase, intestinal tumor burden in ApcΔ14/+ mice

Immature forms of the peptide hormone gastrin have been implicated in the development of colorectal cancer (CRC). The biological activity of glycine-extended gastrin (Ggly) is dependent on the binding of Fe³⁺ ions in vitro and in vivo. The aim of the present study was to determine the effect of blocking Fe³⁺ ion binding to Ggly, using Bi³⁺, In³⁺ or Ru³⁺ ions, on the development of intestinal tumors in APC^Δ14/+ mice. APC^Δ14/+ mice were treated orally with Bi³⁺, In³⁺ or Ru³⁺ ions for up to 60 days, serum trace metals were analyzed by inductively coupled plasma mass spectrometry, and the incidence and size of intestinal tumors were assessed. Bi³⁺ treatment significantly decreased the number of tumors larger than 3 mm in male mice. In³⁺ or Ru³⁺ treatment significantly increased the tumor burden in all animals and In³⁺ increased the number of tumors larger than 3 mm or 5 mm in male mice alone. The fact that binding of In³⁺ or Ru³⁺ ions to Ggly was orders of magnitude stronger than the binding of Bi³⁺ ions implies that the inhibitory effect of Bi³⁺ ions is not a consequence of a reduction in Ggly activity. However, further testing of higher doses of Bi³⁺ ions for longer periods as an oral treatment for intestinal tumors is warranted.

Studies on the toxicity and distribution of indium compounds according to particle size in sprague-dawley rats

OBJECTIVES

The use of indium compounds, especially those of small size, for the production of semiconductors, liquid-crystal panels, etc., has increased recently. However, the role of particle size or the chemical composition of indium compounds in their toxicity and distribution in the body has not been sufficiently investigated. Therefore, the aim of this study was to examine the effects of particle size and the chemical composition of indium compounds on their toxicity and distribution.

METHODS

Male Sprague-Dawley rats were exposed to two different-sized indium oxides (average particle sizes under 4,000 nm [IO_4000] and 100 nm [IO_100]) and one nano-sized indium-tin oxide (ITO; average particle size less than 50 nm) by inhalation for 6 hr daily, 5 days per week, for 4 weeks at approximately 1 mg/m(3) of indium by mass concentration.

RESULTS

We observed differences in lung weights and histopathological findings, differential cell counts, and cell damage indicators in the bronchoalveolar lavage fluid between the normal control group and IO- or ITO-exposed groups. However, only ITO affected respiratory functions in exposed rats. Overall, the toxicity of ITO was much higher than that of IOs; the toxicity of IO_4000 was higher than that of IO_100. A 4-week recovery period was not sufficient to alleviate the toxic effects of IO and ITO exposure. Inhaled indium was mainly deposited in the lungs. ITO in the lungs was removed more slowly than IOs; IO_4000 was removed faster than IO_100. IOs were not distributed to other organs (i.e., the brain, liver, and spleen), whereas ITO was. Concentrations of indium in the blood and organ tissues were higher at 4 weeks after exposure.

CONCLUSIONS

The effect of particle size on the toxicity of indium compounds was not clear, whereas chemical composition clearly affected toxicity; ITO showed much higher toxicity than that of IO.

Genotoxicity studies of heavy metals: lead, bismuth, indium, silver and antimony

OBJECTIVES

Many kinds of heavy metals are used in industry; thus, it is important for us to clarify their toxicity. For example, lead, which is a component of solder, is notorious for its neurotoxicity, and substitute materials have been sought for many years. Therefore, we examined the genotoxicity of lead and also those of metallic bismuth, indium, silver and antimony which are possible substitutes for lead in solder.

METHODS

Bacterial reverse mutation tests and chromosomal aberration tests in cultured mammalian cells were performed according to standard procedures.

RESULTS

Antimony showed genotoxicity in both tests, and bismuth also showed positive results in the chromosomal aberration test. In contrast, lead, indium, and silver were considered to be inactive by the criteria of the present study.

CONCLUSIONS

Although further studies are needed because of the difficulty of genotoxicity evaluation using an in vitro system, sufficient precautions should be made when antimony and bismuth are used.