The focus of solid microneedles technology to date has largely been on cosmetology, vaccination, and insulin delivery, etc. However, limited information is available about the safety of solid polymer microneedles applied in different parts of the human body. In consideration of the different application sites of cosmetology, vaccination, and insulin delivery involved with microneedles technique, factors influencing user acceptance to microneedles including the length and density as well as the size of microneedle patches were systematically investigated by applying different microneedle patches on the forehead, forearm, and abdomen skins of 18 healthy human participants. Multiple insertion tests demonstrated that solid microneedles with a length of 400 μm, a density of 100 MN/cm2, and an array size of 10 × 10 were optimal for forehead pretreatment. Microneedles with lengths of 400 and 600 μm, densities of 49 and 100 MN/cm2, and an array size of 10 × 10 caused less pain and slight skin irritation in the forearm, whereas 400 μm height, 49 and 100 MNs/cm2 densities, and 5 × 5, 10 × 10, and 10 × 20 arrays of the solid microneedles were not considered painful and were well-tolerated in abdomen insertion. In conclusion, the optimization of the dimensions of microneedles according to application sites could improve medication compliance and the safety of clinical use of solid microneedles.

No abstract

A series of field investigations have been conducted at Yongzhou Pb/Zn/Cu mine tailings, Hunan Province, southern China. The specific aim was to search for new lead accumulators with fast growth rate and large biomass. The results of tissue analyses identified Typha orientalis Presl has a strong accumulation of lead. The average lead concentrations in the leaves and roots are 619 and 1,233 mg/kg, respectively. The growth and Pb content of the plant were also studied by hydroponic culture with different concentrations of Pb(NO(3))(2). Growth of the plant was not affected by Pb up to 300 mg/L. The Pb concentrations in the leaves and roots increased with increasing of Pb level in the modified Hoagland's nutrient solution. The maximum concentrations of Pb in the leaves and roots were 16,190 and 64,405 mg/kg, respectively. The study also demonstrated that EDTA not only increased the amount of Pb taken up by plants but also speeded up the metal translocation from roots to leaves.

No abstract

No abstract