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Abstract We report in this article the microwave synthesis of relatively monodisperse, highly crystalline CdSe quantum dots (QDs) overcoated with Cd0.5Zn0.5S/ZnS multishells. The as-prepared QDs exhibited narrow photoluminescence bandwidth as the consequence of homogeneous size distribution and uniform crystallinity, which was confirmed by transmission electron microscopy. A high photoluminescence quantum yield up to 80% was measured for the core/multishell nanocrystals. Finally, the resulting CdSe/Cd0.5Zn0.5S/ZnS core/multishell QDs have been successfully applied to the labeling and imaging of breast cancer cells (SK-BR3).

Featured Application: The combination of natural plant products and probiotics contribute to regulating the gut microbiota and alleviating liver damage. Epigallocatechin gallate (EGCG) is a main active ingredient in tea, but it is difficult for it to be absorbed and utilized by the body, resulting in limited bioactivity. Therefore, we explored the role of probiotics in enhancing the physiological activity of EGCG in a mice model of liver injury. Mice were methodically treated with either a single ingredient or a combination of EGCG and Lactiplantibacillus plantarum P101 (LP.P101) for 21 days, and then administrated with intraperitoneal injection of carbon tetrachloride (CCl4) on the last day. As a result, the antioxidative genes were activated and pro-inflammatory genes were suppressed, reducing the oxidative and inflammatory injury of mice, which indicated a better preventive effect of the combination of EGCG and LP.P101 than the single ingredient. Furthermore, 16S rRNA high-throughput sequencing revealed the role of gut microbiota played in liver injury mitigation. The combination of EGCG and LP.P101 increased the relative abundance of Lactobacillus, Akkermansia and other beneficial bacteria that negatively correlated with inflammation and positively correlated with antioxidation. In conclusion, the combination of EGCG and LP.P101 was more effective than the single ingredient in alleviating liver damage caused by CCl4. Altered gut microbiota may be an important cause. [ABSTRACT FROM AUTHOR]

An electrochemical enzyme-linked immobilized DNA-hybridization assay for the detection of Plasmodium falciparum has been developed. The target molecule was a segment of the repeat sequence of the gene coding for the circumsporozoite (CSP) protein from the AF54087 gene. This analyte offers the possibility of specifically detecting P. faleiparum. The assay involves attachment of a biotinylated primary DNA probe via its 5'-amineterminus to the streptavidin-coated surface of microwells in a 96-well plate. The primary DNA probe (1 [sup.0]P, which was of two different sequences we call 1[sup.0][P.sub.a] and 1 [sup.0][P.sub.b]) was used to capture the target (T, which was of two different sequences, [T.sub.1] sequence 481-590 and [T.sub.2] sequence 472-590 of AF54087 gene for the CSP gene) by hybridization to a complementary sequence on the target. On 1 [sup.0][P.sub.a], 47 bases were complementary to [T.sub.1] and [T.sub.2] at 543-590, while on 1 [sup.0][P.sub.b]], 35 bases were complementary to [T.sub.1] and [T.sub.2] at 555-590. A secondary DNA probe that contained 36 bases with alkaline phosphatase (2[sup.0]P-AP) label on the 3' end was hybridized to a complementary base sequence on the 5' end of the target, p-Aminophenol, which is enzymatically generated by the immobilized AP fromp-aminophenyl phosphate (PAPP), is detected using electrochemistry. The peak current of cyclic voltammo-grams from a PAPP solution incubated inside the microwells modified with the complete assembly of the assay components gives a linear relationship with the concentration of the target (2-50 ng/mL, where [P.sub.1][ ([P.sub.1a] and [P.sub.1b]) and [P.sub.2]-AP concentrations are 50 ng/mL). A detection limit of 1.4 ng/mL (or 46 pM) of the DNA target was obtained. The signals of the assays were not significantly affected when performed in the presence of human hepatocytes, pig liver, or chicken serum indicating the viability of this assay in real clinical samples.

A new approach is reported for analysis of ultrasmall volumes. It takes advantage of the versatile positioning of a dispenser to shoot ~150-pL droplets of liquid onto a specific location of a substrate where analysis is performed rapidly, in a fraction of the time that it takes for the droplet to evaporate. In this report, the site where the liquid is dispensed carries out fast-scan cyclic voltammtry (FSCV), although the detection method does not need to be restricted to electrochemistry. The FSCV is preformed at a microactivity having individually addressable gold electrodes, where one serves as working electrode and another as counter/pseudoreference electrode. Five or six droplets of 10 mM [[Ru(N[H.sub.3]).sub.6]] [Cl.sub.3] in 0.1 M KCl were dispensed and allowed to dry, followed by redissolution of the redox species and electrolyte with one or five droplets of water and immediate FSCV, demonstrating the ability to easily concentrate a sample and the reproducibility of redissolution, respectively. Because this approach does not integrate detection with microfluidics on the same chip, it simplifies fabrication of devices for analysis of ultrasmall volumes. It may be useful for singlestep and multistep sample preparation, analyses, and bioassays in microarray formats if dispensing and changing of solutions are automated. However, care must be taken to avoid factors that affect the aim of the dispenser, such as drafts and clogging of the nozzle.

An electrochemical enzyme-linked immobilized DNA-hybridization assay for the detection of Cryptosporidium parvum in water has been developed. The target molecule was a 121-nucleotide sequence from the C. parvum heat shock protein 70 (hsp70 mRNA from U71181 gene). This analyte offers the possibility of distinguishing dead from live oocysts. The assay involves covalent attachment of a primary DNA probe via its 5'-amine-terminus to self-assembled monolayers of mercaptoundecanoic acid to a gold surface. The primary DNA probe was used to capture the target (sequence 1039-1082 of U71181 gene for the mRNA), by hybridization to a 20-base complementary sequence on the target (at sequence 1063-1082). A secondary DNA probe labeled with alkaline phosphatase (AP) was then hybridized to base sequence 1039-1062 on the target, p-Aminophenol, which is enzymatically generated by the immobilized AP from p-aminophenyl phosphate (PAPP), is detected using electrochemistry. The peak current of cyclic voltammograms from a PAPP solution, in which gold-coated silicon wafer modified with the complete assembly of the assay components was incubated, is linear with concentration of the target (5-50 [micro]g/mL, where [P.sub.1] and [P.sub.2]-AP concentrations are 50 [micro]g/mL). A detection limit of 2 [micro]g/mL (or 146 nM) of the DNA target was obtained. Cross-reactivity tests showed high selectivity for heat-shocked C. parvum. No signal was obtained for either the synthetic DNA for hsp70 of Campylobacter lari, Escherichia coli, Giardia lamblia, Salmonella typhimurium, and Listeria monocytogenes or for the products of heat-shocked whole organisms of E. coli, G. lamblia, Staphylococcus aureus, and Cryptosporidium muris.

A self-contained, microelectrochemical immunoassay on the smallest volumes reported to date (1 [micro]L for the antigen, 1 [micro]L for the secondary antibody-enzyme conjugate, and 200 nL for the electrochemically detected species) has been developed using mouse IgG as a model system in a sandwich-type enzyme-linked immunosorbant assay, which takes less than 30 min to both complete the assembly of immunoassay components onto the antibody-modified surface and detect enzymatically generated species (excluding time for electrochemical cleaning of electrodes). These studies demonstrate the advantage of the close proximity of electrodes to modified surfaces and their application in the analysis of small volumes. Using a 50 [micro]m diameter x 8 [micro]m deep cavity with individually addressable electrodes on a microfabricated chip, the primary antibody was selectively and covalently attached at a gold, recessed microdisk (RMD) at the bottom of the microcavity to the free end of SAMs of either 11-mercaptoundecanoic acid or 11-mercapto-1-undecanol using 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride. Nonspecific adsorption to the surrounding material, polyimide, of the microcavity device was eliminated. Electrochemical desorption was used to confine the immunoassay activity at the RMD. Enzymatic conversion of the substrate p-aminophenyl phosphate to p-aminophenol is detectable in less than 30 s using cyclic voltammetry at a gold, tubular nanoband electrode, which is on the wall of the microcavity and immediately adjacent to the modified RMD. A third electrode, also within the region of the microcavity, served as the pseudoreference/auxiliary electrode. Calibration curves obtained for 1-[micro]L solutions of 5-100 ng/mL of IgG and for 200 nL-solutions of 5 [micro]M to 4 mM of PA[P.sub.R] gave detection limits of 4.4 nM (6.4 ng/mL) or 880 fmol (129 pg) for PA[P.sub.R] and 56 fM (9 pg/ mL) or 56 zmol (9 fg) for IgG. It is expected that the device may be suitable for analysis with volumes down to tens of picoliters.

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in food, medical, and other fields; their reproductive toxicity has been reported in numerous studies. However, the relevant toxicity mechanism still requires further exploration. In this paper, the effect of oral exposure to 500 mg/kg TiO2 NPs (anatase and rutile) in adult male SD rats was studied over 3 and 7 days. Results showed that the total sperm count and testosterone level of 7 days of exposure in serum decreased in the experimental group. Testicular tissue lesions, such as disappearance of Leydig cells, disorder of arrangement of spermatogenic cells in the lumen of convoluted seminiferous tubules, and disorder of arrangement of germ cells, were observed. Meanwhile, the expression of steroidogenic acute regulatory (StAR; the key factors of testosterone synthesis), MAPK (ERK1/2), and phosphorylated ERK1/2 in testes of SD rats after exposure to TiO2 NPs for 7 days decreased, while the malondialdehyde content increased and superoxide dismutase activity decreased in serum. The present study showed that TiO2 NPs could cause reproductive toxicity. Notably, anatase is more toxic than rutile. In addition, exposure to 500 mg/kg TiO2 NPs for 7 days inhibited testosterone synthesis in male rat, which may be related to the reactive oxygen species (ROS)-MAPK (ERK1/2)-StAR signal pathway. Warning that the use of TiO2 NPs should be regulated. [ABSTRACT FROM AUTHOR]

The potential toxicity of Zinc oxide nanoparticles (ZnO NPs) to human beings has become a widespread concern. This study explored the reproductive toxicity and the mechanism of toxicity of ZnO NPs in early pregnant mice. The results showed that abnormal weight changes, induced inflammation, reduced level of serum sex hormones, damaged uterus, increased abortion, and abnormal development of fetus. In the uterus, the transcription levels of ZnT‐1, HO‐1, Bax, Bax/Bcl‐2, JNK, and Caspase‐3 were significantly up‐regulated while Bcl‐2, ER‐1 and PR were significantly down‐regulated. The TUNEL‐positive cells increased that were exposed to high levels of ZnO NPs. In summary, those results indicated that Zn from high levels of exposure to ZnO NPs accumulated in the uterus that could have caused the formation of ROS that led to oxidative stress, which might have activated the mitochondrial apoptotic pathway that could have caused the uterine injury which induced the observed reproductive toxicity. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles (NPs) are among the most manufactured nanoparticles in the consumer products, industries, and researches. An increasing body of evidence indicated that ZnO NPs show toxicological effects in vivo. Sex differences in the toxicity of ZnO NPs are not clear, thus the aim of this study was to investigate the effects of ZnO NPs on the female and male reproductive organs (uterus, ovary and testes). ZnO NPs were orally administered to female and male mice at dosages level of 0 and 100 mg/kg body weight. The biological material was sampled 3 days after tube feeding. The results demonstrated that Zinc contents were accumulated in the reproductive organs of treated mice. Furthermore, ZnO NPs administration induced significant decrease in the testes weight, an imbalance of hematological and serum biochemical parameters in male mice. The histopathological examinations showed that structural disorder and the appearance of cell apoptosis and death in the ZnO NPs‐exposed mice. Additionally, the RT‐qPCR data indicated ZnO NPs can activate mitochondrial‐mediated signaling pathway and induce caspase depend damage that ultimately injured the uterus. In the ovary, ZnO NPs induce cell apoptosis in Shh pathway activated ovary cells, and affect the synthesis of steroidogenesis. In the testes, ZnO NPs effectively changed the expression level of genes related to oxidant stress, detox/metabolic process, and apoptosis. It was found that ZnO NPs caused more serious reproductive toxicity in the male mice than female mice. Overall, these findings indicated that ZnO NPs could induce exposure‐related risks to reproductive health, especially in those who are at the occupational level. [ABSTRACT FROM AUTHOR]

In this work, we aimed to evaluate the adverse effects and the mechanism of intestinal barrier caused by titanium dioxide nanoparticles (TiO2 NPs). Here, the effects of two different dosages (300 and 1200 mg/kg) of TiO2 NPs on female mice (n = 5) were investigated. After 28‐day oral exposure, the results of Ti content were significantly increased in the ileum in comparison with the control. The histopathological structure index of the ileum was significantly changed after TiO2 NPs exposure; villi height and crypt depth were decreased and increased, respectively. Meanwhile, TiO2 NPs treatment also significantly altered the transcription levels of genes. First, the GATA‐3 and STAT‐4 were upregulation and downregulation, respectively. Second, gene expressions of the Zonula Occludens‐1, claudin (CLDN)‐12, occludin, and myosin light chain kinase were significantly upregulated, while the CLDN‐3 was decreased. Finally, the caspase‐3, caspase‐9, and caspase‐12 were upregulated. The results of TUNEL staining indicated apoptosis in the ileum. In general, TiO2 NPs treatment significantly changed the intestine physical barrier in a dose‐dependent manner. The toxicity of TiO2 NPs could be through the imbalance in the Th1/Th2. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have recently attracted considerable attention in the biomedical fields because of their unique and excellent optical properties. However, information on their health effects, particularly in the reproductive system, is limited. The present study focuses on the effects of intravenous injection of CdSe/ZnS QDs on the reproductive system and embryo development at various stages of pregnancy in mice. The CdSe/ZnS QDs intravenously injected in mice during pregnancy accumulated in the maternal liver, uterus and placenta. This accumulation affected the growth and development of the embryo during the early and middle stages of pregnancy. Moreover, genotoxicity to the placenta after exposure to CdSe/ZnS QDs was demonstrated by the increased expression levels of genes related to oxidative stress and apoptosis and the reduced expression levels of genes related to the nutrient and waste transportation. Alterations in the gene expression levels have hindered the transport of metabolites across the placenta, which in turn affected the ability of the fetus to obtain nutrients. [ABSTRACT FROM AUTHOR]

Circulating tumour cells (CTCs) draw significant attention as a promising biomarker for cancer prognosis, status monitoring, and metastasis diagnosis. However, the concentration of CTCs in peripheral blood is usually extremely low, thereby requiring enrichment followed by isolation of CTCs prior to detection. An immunomagnetic separation is a promising tool for CTCs enrichment. In this study, a cost‐effective magnetic separation method, based on streptavidin–biotin complexation, was developed and the effects of magnetic beads' size in CTCs capture were compared. Magnetic nanobeads which were 25 nm in diameter lead to highest capture efficiency (82.2%) compared with 150 nm magnetic beads and 1 µm microbeads. Based on the streptavidin–biotin system, 25 nm magnetic nanobeads could capture model CTCs over 80% efficiency even at concentrations as low as ∼25 cells/mL that may represent the actual level of CTCs in peripheral blood of cancer patients. Furthermore, the isolated cells remained robust and healthy showing insignificant changes in morphology and behaviour when cultured for 24 h immediately after capture and isolation. The magnetic nanobeads based on streptavidin–biotin complexation showed promise for the easy and efficient capture and isolation of healthy CTCs for further diagnosis and analysis. [ABSTRACT FROM AUTHOR]

Circulating tumour cells (CTCs) draw significant attention as a promising biomarker for cancer prognosis, status monitoring, and metastasis diagnosis. However, the concentration of CTCs in peripheral blood is usually extremely low, thereby requiring enrichment followed by isolation of CTCs prior to detection. An immunomagnetic separation is a promising tool for CTCs enrichment. In this study, a cost-effective magnetic separation method, based on streptavidin-Cbiotin complexation, was developed and the effects of magnetic beads' size in CTCs capture were compared. Magnetic nanobeads which were 25 nm in diameter lead to highest capture efficiency (82.2%) compared with 150 nm magnetic beads and 1 μm microbeads. Based on the streptavidin-Cbiotin system, 25 nm magnetic nanobeads could capture model CTCs over 80% efficiency even at concentrations as low as ¡«25 cells/mL that may represent the actual level of CTCs in peripheral blood of cancer patients. Furthermore, the isolated cells remained robust and healthy showing insignificant changes in morphology and behaviour when cultured for 24 h immediately after capture and isolation. The magnetic nanobeads based on streptavidin-Cbiotin complexation showed promise for the easy and efficient capture and isolation of healthy CTCs for further diagnosis and analysis. [ABSTRACT FROM AUTHOR]

Various surface modifications of iron oxide magnetic nanoparticles (IOMNs) can improve their stability and long‐term retention time in vivo, expanding applications of biomedical fields. However, whether the long‐term retention of IOMNs coated with different surface modifications has toxic effects remains poorly understood. Here, the toxicity of IOMNs modified with polyethylene glycol (PEG), bovine serum albumin (BSA), and carboxyl group (COOH), forming PEG–IOMNs, BSA–IOMNs, and COOH–IOMNs, respectively, were evaluated in the rats. The high accumulation of PEG–IOMNs and COOH–IOMNs both in the liver and lung, and the high accumulation BSA–IOMNs in blood after 24 day recovery were observed by elemental content analysis. Except individual neutrophils in the local portal area, PEG–IOMNs can also induce cytoplasmic vacuolisation in partial liver cells by histopathological examination. Furthermore, the results of RT‐qPCR showed that PEG–IOMNs, BSA–IOMNs, and COOH–IOMNs can change the transcript levels of most genes related to iron homeostasis, mitochondria apoptosis, inflammatory response, but <2‐fold alteration. COOH–IOMNs seemed to induce normal cell apoptosis more easily than BSA–IOMNs and PEG–IOMNs. In conclusion, BSA–IOMNs had longer‐term retention time in blood. IOMNs coated with PEG and BSA can still induce side effects on the liver. [ABSTRACT FROM AUTHOR]

Various surface modifications of iron oxide magnetic nanoparticles (IOMNs) can improve their stability and long-term retention time in vivo, expanding applications of biomedical fields. However, whether the long-term retention of IOMNs coated with different surface modifications has toxic effects remains poorly understood. Here, the toxicity of IOMNs modified with polyethylene glycol (PEG), bovine serum albumin (BSA), and carboxyl group (COOH), forming PEG-IOMNs, BSA-IOMNs, and COOH-IOMNs, respectively, were evaluated in the rats. The high accumulation of PEG-IOMNs and COOH-IOMNs both in the liver and lung, and the high accumulation BSA-IOMNs in blood after 24 day recovery were observed by elemental content analysis. Except individual neutrophils in the local portal area, PEG-IOMNs can also induce cytoplasmic vacuolisation in partial liver cells by histopathological examination. Furthermore, the results of RT-qPCR showed that PEG-IOMNs, BSA-IOMNs, and COOH-IOMNs can change the transcript levels of most genes related to iron homeostasis, mitochondria apoptosis, inflammatory response, but <2-fold alteration. COOH-IOMNs seemed to induce normal cell apoptosis more easily than BSA- IOMNs and PEG-IOMNs. In conclusion, BSA-IOMNs had longer-term retention time in blood. IOMNs coated with PEG and BSA can still induce side effects on the liver. [ABSTRACT FROM AUTHOR]

Ultra-fine-ZnO showed low toxicity in complex water matrix containing multiple components such as PBS buffer and the toxic mechanism of ultra-fine-ZnO has not been clearly elucidated. In present study, enhanced antibacterial activity of 200 nm diameter ultra-fine-ZnO in PBS buffer against Bacillus cereus and Escherichia coli were observed in the presence of several organic acids in comparison with ultra-fine-ZnO in PBS buffer alone. These findings indicated that the toxic effects of the ultra-fine-ZnO was dependent on the concentration of released Zn 2+ which was affected by organic acids. The production of reactive oxygen species (ROS) did not responsible to the toxic mechanism of ultra-fine-ZnO which was tested using the antioxidant N -Acetylcysteine (NAC). Indeed, ultra-fine-ZnO induced bacteria cell membrane leakages and cell morphology damages that eventually led to cell death, which were confirmed using propidium monoazide (PMA) in combination with PCR and scanning electron microscopy (SEM). All data gathered herein suggested that released Zn 2+ played a major role in the microbial toxicity of ultra-fine-ZnO. [ABSTRACT FROM AUTHOR]