Brain-targeted delivery of obidoxime, using aptamer-modified liposomes, for detoxification of organophosphorus compounds.

Effective intracerebral delivery acetylcholinesterase (AChE) reactivator is key for the acute organophosphorus (OPs) poison treatment. However, the blood-brain barrier (BBB) restricts the transport of these drugs from blood into the brain. Herein, we developed transferrin receptor (TfR) aptamer-functionalized liposomes (Apt-LP) that could deliver AChE reactivator (obidoxime) across the BBB to act against paraoxon (POX) poisoning. The aptamer had strong affinity for TfR and was modified with 3'-inverted deoxythymidine (dT) to improve serum stability. The uptake of Apt-LP by bEnd.3 cells was significantly higher than that of non-targeting liposomes. The ability of Apt-LP to penetrate intact BBB was confirmed in in vitro BBB mice model and in vivo biodistribution studies. Treatment of POX-poisoned mice with Apt-LP-LuH-6 reactivated 18% of the brain AChE activity and prevented brain damage to some extent. Taken together, these results showed that Apt-LP may be used as a promising brain-targeted drug delivery system against OPs toxicity.

Fabrication of pioneering 3D sakura-shaped metal-organic coordination polymers Cu@L-Glu phenomenal for signal amplification in highly sensitive detection of zearalenone.

Low molecular weight pollutants from foods have aroused global attention due to their toxicity after long-time exposure. There is an increased demand for appropriate methods to detect these pollutants in foods. In this study, a brand-new type of nano metal-organic coordination polymers (MOCPs) nanocarriers (3D sakura-shaped copper (II) ions@L-glutamic acid (L-Glu)) has been first synthesized. We herein demonstrate a facile chelated method that allows the combination of copper (II) ions and L-Glu. A series of controlled experiments have revealed that the reaction time and the ratio of reactants played the crucial roles in affecting the morphology of the final product. 3D sakura-shaped Cu@L-Glu combined with palladium-platinum nanoparticle (Pd-PtNPs) to obtain Cu@L-Glu/Pd-PtNPs acting as the signal tag, which applied in electrochemical aptasensor for ultrasensitive detection of zearalenone (ZEN). A glassy carbon electrode was first modified with spherical Au-PANI-Au nanohybrids to enhance the conductivity and immobilize more amino modified ZEN aptamer. Cu@L-Glu/Pd-PtNPs were labeled with Complementary DNA (partial matching with ZEN aptamer) to form bioconjugates for signal amplification. After the hybridization reaction of ZEN aptamer and the bioconjugates, a significant electrochemical signal from the catalysis of H2O2 by Cu@L-Glu/Pd-PtNPs can be observed. ZEN competed with bioconjugates for binding to ZEN aptamer, resulting in decreased the electrochemical signal. Chronoamperometry was applied to record the final electrochemical signals. Under optimal conditions, the electrochemical aptasensor exhibited desirable sensitive detection of ZEN with a wide linearity ranging from 1 fg/mL to 100 ng/mL and a relatively low detection limit of 0.45 fg/mL (S/N = 3). Furthermore, the proposed electrochemical aptasensor shows excellent selectivity to the ZEN in the presence of possible interfering substances, and has potential application for ZEN detection in food samples.

Target triggered cleavage effect of DNAzyme: Relying on Pd-Pt alloys functionalized Fe-MOFs for amplified detection of Pb2.

We designed an amplified detection strategy for the sensitive determination of lead ions (Pb2+) based on a target-triggered nuclear acid cleavage of Pb2+-specific DNAzyme as a selectivity interface combined with Pd-Pt alloys modified Fe-MOFs (Fe-MOFs/PdPt NPs) hybrids acting as the signal tag. Streptavidin modified reduced graphene oxide-tetraethylene pentamine-gold nanoparticles (rGO-TEPA-Au) served as a sensor platform for immobilizing more DNAzyme. In the presence of Pb2+, the substrate DNA strand can be specifically cleaved at the ribonucleotide site by DNAzyme to produce a new single-DNA on the interface. Then, the hairpin DNA with hybrid strand matched by its complement to the single-DNA was employed to modify the Fe-MOFs/PdPt NPs bioconjugates for signal amplification. Fe-MOFs/PdPt NPs catalyze hydrogen peroxide (H2O2) to produce the electrochemical signal which was recorded by chronoamperometry. Benefiting from the Pb2+-dependent DNAzyme, the proposed method can selectively detect Pb2+ in the presence of other metal ions. The newly designed biosensor exhibited a good linear relationship ranging from 0.005 to 1000nmolL-1 with a low detection limit of 2pM (S/N = 3) for Pb2+. This Pb2+-dependent DNAzyme based ultrasensitive biosensor showed high sensitivity and selectivity, providing potential application for Pb2+ detection in naturally contaminated sewage and spiked drinking water samples.

An impedimetric biosensor for the diagnosis of renal cell carcinoma based on the interaction between 3-aminophenyl boronic acid and sialic acid.

Renal cell carcinoma (RCC) often expresses a high density of sialic acid-rich glycoproteins which helps these late-stage cancer cells to enter the blood stream or urine. Blood diagnosis is a complex and time-consuming process. In this study, we developed a facile and non-invasive electrochemical cytosensor for early detection of RCC in urine samples based on specific recognition by 3-aminophenyl boronic acid (APBA). Polypyrrole (PPy) and bovine serum albumin (BSA)-incorporated Ag submicron particles (Ag@BSA) were co-deposited on a gold electrode (GE) to take advantages of the excellent properties of these biomaterials, including good biocompatibility, low cytotoxicity and excellent electro-conductivity. To further increase the biosensor's sensitivity, APBA molecules were integrated to recognize sialic acid (SA) on the cell surface. Under optimal conditions, the impedimetric cytosensor exhibited a good linear relationship with the logarithm of the cell concentration from 17 to 1.7×106 cellsmL-1, and the low detection limit was 6 cellsmL-1 (S/N=3). Therefore, the electrochemical impedimetric biosensor offers a potential approach to bedside rapid detection of RCC in clinical applications.

A switched catalysis qualified sealers capped one-step synthesis biocompatibility bimetallic scaffold film for Neu5Acα(2-6)Gal ß MP Glycoside specific detection.

In this work, a novel label-free biosensor was designed for the sensitive and selective determination of Neu5Acα(2-6)Gal ß MP Glycoside using AuPt-PPy(polypyrrole) conductive nanocomposite film as the sensor platform. The introduced AuPt-PPy nanocomposite provided a large surface area for the immobilization of Sambucus nigra agglutinis (SNA) through a coupling agent for specifically recognizing analytes and exhibited high electrocatalytic activity toward the reduction of hydrogen peroxide (H2O2) as an analytical signal. Subsequently, to block the non-specific sites of the modified electrode, GOx was employed instead of the usual sealers. Most importantly, in the presence of glucose, these localized GOx further enhanced the electrochemical signal, which was achieved by the efficient catalysis of glucose. This study is the first that demonstrates the specific detection of Neu5Acα(2-6)Gal ß MP Glycoside using AuPt-PPy as the electrocatalytic. Under optimal conditions, the electrochemical biosensor exhibited a wide linear range of 0.01 pgmL(-1)-800 ngmL(-1) with a low detection limit of 0.003 pgmL(-1) (S/N=3), due to the affinity between SNA and Neu5Acα(2-6)Gal ß MP Glycoside. Therefore, the co-catalysis signal amplification approach has considerable potential in clinical applications and is suitable for the quantification of other biomarkers.

A novel DNA biosensor integrated with Polypyrrole/streptavidin and Au-PAMAM-CP bionanocomposite probes to detect the rs4839469 locus of the vangl1 gene for dysontogenesis prediction.

The single nucleotide polymorphism (SNP) of the vangl1 gene is highly correlated with Neural Tube Defects (NTDs), a group of severe congenital malformations. It is hindered by the lack of a quantitative detection method. We first propose the use of a DNA biosensor to detect the missense single nucleotide polymorphism (rs4839469 c.346G>A p.Ala116Thr) of the vangl1 gene in this work. Polypyrrole (PPy) and streptavidin were integrated to modify a gold electrode. We took advantage of the PPy's good biocompatibility and excellent conductivity. To further accelerate the electron transfer process at the electrode surface, polyamidoamine dendrimer-encapsulated gold nanoparticles (Au-PAMAM) were used, because Au-PAMAM possess a large number of amino groups to load capture probes (CP). Using the biotin-streptavidin system, the Au-PAMAM-CP bionanocomposite probe, which can detect the target DNA, was conjugated to the electrode surface. Under optimal conditions, the DNA biosensor exhibited a wide linear range of 0.1-100 nM with a low detection limit of 0.033 nM (S/N=3). The results suggest that this approach has the potential to be used in clinical research.

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses.

BACKGROUND: Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported. METHODS: The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains. RESULTS: Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed. CONCLUSION: Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3-100%. However, the inter-species similarities were relatively low, ranging from 68.7-97.9%. The housekeeping genes rpoB and gyrB1 were demonstrated to be alternative classification markers to the species level based on intra- and inter-species comparisons, whereas based on phylogenetic tree rpoB proved to be reliable phylogenetic marker for the genus Prevotella.

Antimicrobial resistance and prevalence of resistance genes of obligate anaerobes isolated from periodontal abscesses.

BACKGROUND: This study attempts to determine the antimicrobial resistance profiles of obligate anaerobic bacteria that were isolated from a periodontal abscess and to evaluate the prevalence of resistance genes in these bacteria. METHODS: Forty-one periodontal abscess samples were cultivated on selective and non-selective culture media to isolate the oral anaerobes. Their antibiotic susceptibilities to clindamycin, doxycycline, amoxicillin, imipenem, cefradine, cefixime, roxithromycin, and metronidazole were determined using the agar dilution method, and polymerase chain reaction assays were performed to detect the presence of the ermF, tetQ, nim, and cfxA drug resistance genes. RESULTS: A total of 60 different bacterial colonies was isolated and identified. All of the isolates were sensitive to imipenem. Of the strains, 6.7%, 13.3%, 16.7%, and 25% were resistant to doxycycline, metronidazole, cefixime, and amoxicillin, respectively. The resistance rate for both clindamycin and roxithromycin was 31.7%. Approximately 60.7% of the strains had the ermF gene, and 53.3% of the amoxicillin-resistant strains were found to have the cfxA gene. Two nim genes that were found in eight metronidazole-resistant strains were identified as nimB. CONCLUSIONS: In the present study, the Prevotella species are the most frequently isolated obligate anaerobes from periodontal abscesses. The current results show their alarmingly high resistance rate against clindamycin and roxithromycin; thus, the use of these antibiotics is unacceptable for the empirical therapy of periodontal abscesses. A brief prevalence of four resistance genes in the anaerobic bacteria that were isolated was also demonstrated.

Sodium fluoride activates ERK and JNK via induction of oxidative stress to promote apoptosis and impairs ovarian function in rats.

The toxicity of sodium fluoride (NaF) to female fertility is currently recognized; however, the mechanisms are unclear. Previously, we reported a reduction in successful pregnancy rates, ovarian atrophy and dysfunction following exposure to NaF. The purpose of this study was to elucidate the underlying molecular mechanisms. Female Sprague-Dawley rats (10 rats/group) received 100 or 200mg/L NaF in their drinking water for 6 months or were assigned to an untreated control group. Apoptotic indices and oxidative stress indicators in blood and ovarian tissue were analyzed following sacrifice. The results confirmed the NaF-induced ovarian apoptosis, with concomitant activation of oxidative stress. Further investigations in ovarian granular cells showed that exposure to NaF activated extracellular regulated protein kinase (ERK) and c-Jun NH2 kinase (JNK), disrupting the ERK and JNK signaling pathways, while p38 and PI3K remained unchanged. These data demonstrated that oxidative stress may play a key role in NaF-induced ovarian dysfunction by activating the apoptotic ERK and JNK signaling pathways.

Effects of sodium fluoride on reproductive function in female rats.

The aim of this study was to investigate the effects of sodium fluoride (NaF) on female reproductive function and examine the morphology of the ovaries and uteri of rats exposed to NaF. Eighty female Sprague-Dawley (SD) rats were divided randomly into four groups of 20: one control group and three NaF treated groups. The three NaF treated groups received 100, 150, and 200 ppm, respectively, of NaF for 6 months via their drinking water, while the control group (GC) received distilled water. The levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), progesterone (P) and estradiol (E2) were measured using an enzyme-linked immunosorbent assay. Pathomorphological evaluation of the uteri and ovaries was conducted after staining with hematoxylin-eosin and immunohistochemistry. The rate of successful pregnancy in the NaF-treated groups declined in a dose-dependent manner. The concentration of reproductive hormones was significantly lower in the three NaF-treated groups, and the endometrium was damaged. The maturation of follicles was inhibited. In addition, the total number of follicles of all types was significantly lower in the NaF-treated groups. These results suggest that female reproductive function is inhibited by NaF and that exposure to NaF causes ovarian and uterine structural damage. NaF may thus significantly reduce the fertility of female rats.

The toxicity mechanism of sodium fluoride on fertility in female rats.

Recognition of the harmful effects of sodium fluoride (NaF) on human reproduction is increasing, especially as it relates to female reproduction. However, the mechanism by which NaF interferes with female reproduction is unclear. The aims of the present study were to investigate the effects of fluoride exposure on female fertility and to elucidate the mechanisms underlying these effects. Female Sprague-Dawley rats were divided into three groups: one control group and two NaF-treated groups (100 and 200 mg/L in the drinking water for 12 weeks). Several parameters were evaluated, including: (i) fluoride concentrations; (ii) estrogen (E2) and progesterone (P) concentrations; (iii) estrogen receptor alpha protein (ERα); (iv) progesterone receptor (PgR) protein; (v) follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) protein. The results indicated that administration of NaF lead to significant decreases in E2 and P levels in the serum and in the expression of FSHR protein. In addition, fluoride exposure significantly increased Erα and PgR protein expression levels and LHR protein expression. These results suggest that the reproductive hormone reduction and the abnormalities of related receptor proteins expression are important factors underlying the decreased fertility observed in female rats that have been exposed to NaF.

[Distribution of anaerobes in periodontal abscess and its resistance to antibiotics].

OBJECTIVE: To isolate and culture the predominant anaerobes from the periodontal abscesses, and to test the antibiotic susceptibility and drug resistant genes of the strains. METHODS: The isolated strains were identified by both API20A biochemical method and polymerase chain reaction (PCR) method. The antibiotic susceptibility test was performed by agar dilution method. The resistant genes of the drug-resistant strains obtained were screened by PCR. RESULTS: The anaerobes were detected in 48% (28/58) of the samples and Prevotella melaninogenica (Pm) was mostly identified in 43% (12/28). API20A biochemical method had 82% (23/28) agreement with the 16SrRNA method in identification rate. Anaerobes were resistant to metronidazole, clindamycin and cefmetazole. The erythromycin-resistant methylase genes F (ermF) gene was detected in three of eight clindamycin resistant strains. None of them was found coded on bacterial plasmids. However, no metronidazole resistant gene was detected on drug resistant strains. CONCLUSIONS: Pm was the predominant species dectected in the periodontal abscess of the patients. The antibiotic agents should be used based on the genotypes and general condition of the patients.