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One-step fluorescence immunochromatographic assay (FICA) has been developed using fluorescent microspheres-labelled monoclonal antibody (McAb) probe for the rapid detection of copper ions in herbal plants and soil samples were investigated in this study. The results can be read by the fluorescence reader according to the fitted standard curve equation. Under optimal conditions, detecting copper ions with FICA can be done within 15 min with a LOD (limit of detection) of 0.2 μg/L, and was very useful for the rapid onsite testing. A total of 31 solid samples were pre-treated by microwave digestion combined with cation exchange solid phase extraction and prepared as test samples for FICA and ICP-AES. The two methods showed good relativity with correlation coefficients of 0.924 and 0.969 in herbal plants and soil samples for copper detection, respectively. We hope that our research can help promote the daily monitoring of heavy metal pollution effectively.

Recently, researchers have sought to better understand the relationship between chromosomal structure and function. Chromosomes, primarily composed of DNA and histone proteins, must replicate prior to cell division. During replication, errors can be introduced into the DNA via physical or chemical stressors, including heat, ultraviolet radiation, and other forms of radiation, heavy metal ions, drugs and organic reagents.1,2) However, it is also probable that chromosomal alterations might be introduced outside of replication, such as during the trypsinization or ethidium bromide (EB) staining processes 3) commonly used in visualization of chromosomes by optical microscopy. Changes of chromosome ultrastructure cannot be observed clearly under conventional optical microscopes due to technical difficulties such as diffraction limitations. However, the advent of atomic force microscopy (AFM) 4) has allowed researchers to investigate small alterations in chromosome structure and morphology.Previous studies have examined changes in chromosome structure caused by physicochemical treatments.5,6) Acetic acid, which is frequently used to remove cellular contaminants, was applied to barley chromosomes at concentrations of 15, 30 and 45%. AFM analysis revealed that the optimal concentration was 30%; at lower levels sufficiently clean chromosomes samples could not obtain and the chromosome surface structures could not be observed, and at higher levels the chromosome structures were significantly damaged, although the cellular contaminants were effectively removed. 7)Similar studies identified chromosomal damages induced by treatments with NaCl 8) and heavy ion radiation. 9)EB, a heterocyclic organic compound, can insert between base pairs, 10) resulting in increasing DNA rigidity and lengthening of DNA.11) Low doses of EB can induce DNA denaturation and can lead to cancer formation. 12) Thus, it is possible that EB staining of chromosome preparations may induce structural abnormalities 13) not present in the actual organism. Up to now, though there are some works about structural changes of chromosomes caused by physicochemical treatments, 3,5,6,[14][15][16] however, no previous work has used AFM to examine the effects of time-course of trypsin or different dose EB on chromosomal structures.In this article, we used AFM in the tapping mode to examine chromosomal damage induced by EB treatment and trypsin digestion in air. Our results showed that EB could profoundly damage human chromosomes, leading to breakages and separations in a dose-dependent fashion. We also found that trypsinization could obviously change the morphological features of chromosomes with increased digestion time; the optimal digestion time for AFM analysis appeared to be 10-20 s under our experimental conditions, but not to be over 40 s. In addition, our results indicate that AFM is a powerful tool for studying chromosomal damage, perhaps indicating that it will be applicable to further diagnostic applications. Together, our results indicate that common chr...

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