miR-1246-overexpressing exosomes improve UVB-induced photoaging by activating autophagy via suppressing GSK3ß.

Stem cell paracrine has shown potential application in skin wound repair and photoaging treatment. Our previous study demonstrated that miR-1246-overexpressing Exosomes (OE-EXs) isolated from adipose-derived stem cells (ADSCs) showed superior photo-protecting effects on UVB-induced photoaging than that of the vector, however, the underlying mechanism was unclear. The simultaneous bioinformatics analysis indicated that miR-1246 showed potential binding sites with GSK3ß which acted as a negative regulator for autophagy. This study was aimed to explore whether OE-EXs ameliorate skin photoaging by activating autophagy via targeting GSK3ß. The results demonstrated that OE-EXs significantly decreased GSK3ß expression, enhanced autophagy flux and autophagy-related proteins like LC3II, while suppressed p62 expression. Meanwhile, OE-EXs markedly reversed the levels of intracellular ROS, MMP-1, procollagen type I and DNA damage in human skin fibroblasts caused by UVB irradiation, but the ameliorating effects were significantly inhibited when 3-Methyladenine (3-MA) was introduced to block the autophagy pathway. Further, OE-EXs could reverse UVB-induced wrinkles, epidermal hyperplasia, and collagen fibers reduction in Kunming mice, nevertheless, the therapeutical effects of OE-EXs were attenuated when it was combinative treated with 3-MA. In conclusion, OE-EXs could cure UVB induced skin photoaging by activating autophagy via targeting GSK3ß.

Study on prenatal diagnosis and pregnancy outcome analysis of fetuses with cardiac rhabdomyoma.

OBJECTIVE: To investigate the prenatal imaging characteristics, genetic characteristics and pregnancy outcome of fetuses with cardiac rhabdomyoma. STUDY DESIGN: The prenatal ultrasound, cranial MRI imaging information and genetic test results of 35 fetuses prenatally diagnosed with cardiac rhabdomyoma were collected and retrospectively analyzed, and the pregnancy outcome was followed up. RESULT: Cardiac rhabdomyomas mainly occurred in left ventricular wall and ventricular septum; cranial MRI imaging was found abnormal in 38.1% (8/21) of the fetuses; genetic test was found abnormal in 58.82% (10/17) of the fetuses; the fetus was born in 12 cases and the pregnancy was terminated in 23 cases. CONCLUSION: TRIO whole exome sequencing (TrioWES) is recommended as the genetic test regime for cardiac rhabdomyoma. The comprehensive evaluation of prognosis of fetuses needs to consider the genetic results and whether the brain is involved; the prognosis of fetuses with simple cardiac rhabdomyoma is good.

[Clinical phenotype and genetic analysis of a fetus with Glutaracidemia type II C].

OBJECTIVE: To explore the clinical phenotype and genetic variants of a fetus with Glutaracidemia type II C (GA II C). METHODS: Clinical data of a 32-year-old pregnant woman and her fetus with GA II C diagnosed at the Third Affiliated Hospital of Zhengzhou University in December 2021 due to the enlargement and enhanced echo of the kidneys and oligohydramnios fluid at 17 weeks were analyzed retrospectively. Amniotic fluid sample of the fetus and peripheral blood samples of the couple were collected for whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. Copy number variation (CNV) was detected by using low-coverage whole genome sequencing (CNV-seq). RESULTS: At 18 weeks' gestation, ultrasound revealed that the fetus had enlargement and enhanced echo of the kidneys along with no echo of renal parenchymal tubular fissure and oligohydramnios. MRI at 22 weeks' gestation confirmed that both kidneys were enlarged with uniformly increased abnormal T2 signal and decreased DWI signal. The volume of both lungs was small, with slightly higher T2 signal. No CNV was detected in the fetus. WES revealed that the fetus has harbored compound heterozygous variants of the ETFDH gene, namely c.1285+1G＞A and c.343_344delTC, which were inherited from its father and mother, respectively. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were classified as pathogenic (PVS1+PM2_Supporting+PS3_Supporting; PVS1+PM2_Supporting+PM3). CONCLUSION: The c.1285+1G＞A and c.343_344delTC compound heterozygous variants of the ETFDH gene probably underlay the disease in this fetus. Type II C glutaric acidemia may manifest as bilateral kidney enlargement with enhanced echo and oligohydramnios. Discovery of the c.343_344delTC has enriched the spectrum of ETFDH gene variants.

Long Non-coding RNA H19-Overexpressing Exosomes Ameliorate UVB-Induced Photoaging by Upregulating SIRT1 Via Sponging miR-138.

UVB-induced photoaging is characterized by wrinkle formation, slackness and senile plaques, affecting the health and beauty of human being. Our previous study revealed that exosomes derived from adipose-derived stem cells (ADSCs) could efficiently alleviate UVB-induced photodamage. However, the functional ingredients in exosomes were undefined. LncRNA H19, one of the well-researched lncRNAs in exosomes, exhibits multiple physiological effects. This study aims to demonstrate the photo-protective role of lncRNA H19 on skin photoaging in UVB-irradiated human skin fibroblasts cells (HSFs) and Kunming mice. LncRNA H19-overexpressing exosomes (H19-Exo) were isolated from the supernatant of ADSCs infected with lncRNA H19-loaded lentivirus. The results showed that H19-Exo significantly inhibited MMPs production, DNA damage and ROS generation while enhancing procollagen type I synthesis in UVB-irradiated HSFs. Meanwhile, H19-Exo markedly reversed epidermal thickening and collagen degradation in UVB-irradiated mice. Furthermore, luciferase reporter assays indicated that lncRNA H19 acted as a sponge for miR-138 expression, and SIRT1 was targeted by miR-138. Evidence from both in vitro and in vivo studies also revealed that H19-Exo could enhance SIRT1 expression by knocking down miR-138. In conclusion, lncRNA H19 served as a therapeutic candidate in treating UVB-induced skin photoaging by upregulation of SIRT1 via miR-138.

[Analysis of clinical phenotypes and genetic variants in two children with sporadic cleidocranial dysplasia].

OBJECTIVE: To explore the clinical phenotypes and genetic diagnosis of 2 sporadic cases for cleidocranial dysplasia. METHODS: The clinical data of two cases of CCD admitted to the Third Affiliated Hospital of Zhengzhou University on December 16, 2021 and December 9, 2021 were analyzed retrospectively, and the whole exome sequencing (WES), chromosome microarray analysis and copy number variation sequencing were performed. RESULTS: The main ultrasonographic findings of the fetus had included poorly calcified skull bones, budging of parieto-occipital area, compression and deformation of skull, and loss of nasal bone. The infant's clinical phenotypes included delayed closure of anterior fontanelle, recurrent respiratory tract infection, growth retardation, and clavicular hypoplasia. By WES analysis, the fetus was found to harbor a heterozygous c.911_914delinsTTT variant of the RUNX2 gene, whilst the infant was found to harbor a heterozygous c.1008delT variant of the RUNX2 gene. Both variants were verified by Sanger sequencing to have occurred de novo. CONCLUSION: For sporadic cases featuring cleidocranial dysplasia, prenatal ultrasonography is particularly important. Hypoplastic clavicle, skull calcification and nasal bone absence are the main features. Diagnosis should also be suspected for infants featuring growth retardation, recurrent respiratory tract infections and clavicular dysplasia. The identification of the c.911_914delinsTTT and c.1008delT variants of the RUNX2 gene has facilitated genetic counseling and prenatal diagnosis, and also expanded the mutational spectrum of the RUNX2 gene.

miR-221/222 Promote Endothelial Differentiation of Adipose-Derived Stem Cells by Regulation of PTEN/PI3K/AKT/mTOR Pathway.

Adipose-derived stem cells (ADSCs) are a type of adult mesenchymal stem cell that show a repair effect on ischemic tissues owing to their capacity for endothelial differentiation. MicroRNA-221/222 (miR-221/222) has been extensively studied in endothelial cells (ECs). However, the mechanism that regulates ADSCs differentiation into ECs remains unknown. In this study, we investigated the effects of miR-221/222-overexpression/silence in ADSCs on endothelial differentiation by constructing lentiviral vectors. Differentiation capacity was assessed by measuring the expression of endothelial markers (CD31, CD34, and CD144). In addition, low-density lipoprotein (LDL) uptake and tube-like formation were performed for evaluation of functional characterization. The PTEN/PI3K/AKT/mTOR signaling pathway was investigated using western blotting to clarify the action mechanism of this gene. The revascularization of miR-221/222-transfeted ADSCs was further verified in a rat hind limb ischemia model. The results confirmed that transfection with miR-221/222 promoted the expression of endothelial markers, LDL uptake, and tube-like formation. As expected, the PI3K/AKT signaling pathway was effectively activated when ADSCs showed high expression of miR-221/222 during endothelial differentiation. Furthermore, injection of miR-221/222 transfected ADSCs significantly improved rat hindlimb ischemia, as evidenced by increased blood flow and structural integrity and reduce inflammatory infiltration. The results of this study suggest that miR-221/222 is essential for endothelial differentiation of ADSCs and provides a novel strategy for modulating vascular formation and ischemic tissue regeneration.

miR-1246-overexpressing exosomes suppress UVB-induced photoaging via regulation of TGF-ß/Smad and attenuation of MAPK/AP-1 pathway.

Stem cell therapy is widely employed for the treatment of skin diseases, especially in skin rejuvenation. Exosomes derived from stem cells have been demonstrated to possess anti-photoaging effects; however, the precise components within exosomes that are responsible for this effect remain unknown. Previously, miR-1246 was found to be one of the most abundant nucleic acids in adipose-derived stem cells (ADSCs)-derived exosomes. This study examined whether miR-1246 was the major therapeutic agent employed by ADSCs to protect against UVB-induced photoaging. Lentivirus infection was used to obtain miR-1246-overexpressing ADSCs and exosomes. We then determined the anti-photoaging effects of miR-1246-overexpressing exosomes (OE-EX) on both UVB-irradiated human skin fibroblasts (HSFs) and Kunming mice. The results showed that OE-EX could significantly decrease MMP-1 by inhibiting the MAPK/AP-1 signaling pathway. Meanwhile, OE-EX markedly increased procollagen type I secretion by activating the TGF-ß/Smad pathway. OE-EX also exhibited an anti-inflammatory effect by preventing the UVB-induced degradation of IκB-α and NF-κB overexpression. Animal experiments demonstrated that OE-EX could reduce UVB-induced wrinkle formation, epidermis thickening, and the loss of collagen fibers reduction in Kunming mice. The combined results suggested that miR-1246 is the key component within ADSCs-derived exosomes that protects against UVB-induced skin photoaging.

Contemporary Research Progress on the Detection of Polycyclic Aromatic Hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are a class of the most common and widespread contaminants. The accumulation of PAHs has made a certain impact on the environment and is seriously threatening human health. Numerous general analytical methods suitable for PAHs were developed. With the development of economy, the environmental problems of PAHs in modern society are more extensive and prominent, and attract more attention from environmental scientists and analysts. Deeper understanding of the properties of PAHs depends on the advent of detection methods, which can also be more conducive to promoting the protection of the environment. Till now, more sensitive, more high-speed and more high-throughput analytical tools are being invented and have played important roles in the research of PAHs. In this short review article, we focused mainly on the contemporary analytical methods about PAHs. We started with a brief review on the hazards, migration, distribution and traditional analysis methods of PAHs in recent years, including liquid chromatography, gas chromatography, surface enhanced Raman spectroscopy and so on. We also presented the applications of the modern ambient mass spectrometry, especially microwave plasma torch mass spectrometry, in the detection of PAHs, as well as the far out novel results in our lab by using microwave plasma torch (MPT) mass spectrometry; for example, some new insights about Birch reduction, regular hydrogen addition and the robustness of molecular structure. These studies have demonstrated the versatility of MPT MS as a platform in the research of PAHs.

Preparation of ICA-loaded mPEG-ICA nanoparticles and their application in the treatment of LPS-induced H9c2 cell damage.

Hydrophilic polyethylene glycol monomethyl ether (mPEG) was grafted onto Icariin (ICA) by succinic anhydride to form a polyethylene glycol-Icariin (mPEG-ICA) polymer. The structure of the polymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). mPEG-ICA nanoparticles loaded with ICA were prepared by physical embedding of ICA by dialysis. The particle size was determined to be (220 ± 13.7) nm, and the ζ potential was (2.30 ± 1.33) mV by dynamic light scattering (DLS). Under a transmission electron microscope (TEM), the nanoparticles were spherical, and the morphology was regular. In the medium with pH 7.4, the drug release rate of mPEG-ICA nanoparticles reached (52.80 ± 1.70)% within 72 h. At pH 6.8, the cumulative drug release of nanoparticles reached (75.66 ± 0.17)% within 48 h. Treatment of the nanoparticles with LPS-treated H9c2 cells maintained cell viability, reduced LDH release and exerted antiapoptotic effects. Moreover, ICA-loaded mPEG-ICA nanoparticles significantly decreased the mRNA expression of the myocardial inflammatory cytokines TNF-α, IL-1ß and IL-6M. In conclusion, ICA-loaded mPEG-ICA nanoparticles protected against LPS-induced H9c2 cell injury.

Variation in grain-size characteristics of simulated shrubs as a novel sand-barrier in a wind tunnel experiment.

Sand transport is the main manifestation of sand damage in the arid and semiarid regions globally. It is a huge challenge to stabilize mobile sandy and change them into stable productive ecosystems. The establishment of simulated shrubs is one of the most effective measures to solve the above difficulties as a novel sand-barrier. To clarify simulated shrubs' role in the process of ecological restoration. It will be greatly helpful to incorporate the shelter device proposed in the present work into landscape models for aeolian soil transport, to optimize the parameters associated with the sand-barrier characteristics for aeolian soil stabilization at the field scale. A series of wind tunnel experiments were conducted to analyze the variations of soil grain-size of simulated shrubs with different spatial configurations, row spaces, and net wind speeds. Further, the soil grain-size parameters were calculated by the classic method proposed by Folk and Ward to clarify the change of soil particles resulted from the blocking effects. The average grain-size content of simulated shrubs with different spatial configurations, row spaces, and net wind speeds was dominated by medium sand and fine sand, and the total percentage was more than 90%. Moreover, the sand deposition of simulated shrubs with different spatial configurations increased with the improvement of wind speeds. The average sand deposition of spindle-shaped simulated shrubs in 17.5 × 17.5 cm and broom-shaped simulated shrubs in 17.5 × 26.25 cm under different net wind speeds was the least. The effects of row spaces on average grain-size parameters increased with the improvement of net wind speeds. By calculating the correct characteristics of specific shelter devices proposed in the present work, all of these findings suggest that the application of simulated shrubs will be an important component to further extend ecological engineering projects in arid and semiarid regions.

Novel loss-of-function variants in DNAH17 cause multiple morphological abnormalities of the sperm flagella in humans and mice.

Multiple morphological abnormalities of the flagella (MMAF) is a genetically heterogeneous disorder leading to male infertility. Recent studies have revealed that DNAH17 variants are associated with MMAF, yet there is no functional evidence in support of their pathnogenicity. Here, we recruited two consanguineous families of Pakistani and Chinese origins, respectively, diagnosed with MMAF. Whole-exome sequencing identified novel homozygous DNAH17 variants, which led to loss of DNAH17 proteins, in the patients. Transmission electron microscope analyses revealed completely disorganized axonemal structure as the predominant anomaly and increased frequencies of missings of microtubule doublet(s) 4-7 in sperm flagella of patients. Similar to those found in patients, Dnah17-/- mice also displayed MMAF phenotype along with completely disorganized axonemal structures. Clusters of disorganized microtubules and outer dense fibers were observed in developing spermatids, indicating impaired sperm flagellar assembly. Besides, we also noticed many elongating spermatids with a deformed nuclear shape and abnormal step 16 spermatids that failed to spermiate, which subsequently underwent apoptosis in Dnah17-null mice. These findings present direct evidence establishing that DNAH17 is a MMAF-related gene in humans and mice, extend the clinical interpretations of DNAH17 variants, and highlight an essential and complex role of DNAH17 in spermatogenesis.

Comparison of the physical and functional properties of starch/polyvinyl alcohol films containing anthocyanins and/or betacyanins.

Anthocyanins and betacyanins are two different types of natural pigments. In this study, active and intelligent packaging were prepared by adding anthocyanins or betacyanins or anthocyanins/betacyanins mixture (in the weight ratios of 3:1, 1:1 and 1:3) into starch/polyvinyl alcohol (PVA) films. The physical and functional properties of developed films were compared. Results showed anthocyanins were more pH-sensitive than betacyanins. However, betacyanins were more beneficial to improve the compactness of the films and had stronger hydrogen bonding interactions with film matrix as compared with anthocyanins. The addition of anthocyanins and/or betacyanins slightly decreased the crystallinity of the films but significantly increased the ultraviolet-visible light barrier, water vapor barrier, antioxidant, antimicrobial, and ammonia-sensitive properties of the films. Moreover, the barrier, antioxidant and antimicrobial properties of the films increased with the increase of betacyanins proportion. Amongst different films, the film containing anthocyanins/betacyanins mixture in the weight ratio of 1:3 presented obvious color changes when the film was utilized to monitor the freshness of pork. Our results suggested betacyanins was more beneficial to enhance the barrier, antioxidant and antimicrobial properties of starch/PVA films. Starch/PVA films simultaneously added with anthocyanins and betacyanins were more suitable to monitor the freshness of pork.

Effects of nitrogen fertilizer on structure and physicochemical properties of 'super' rice starch.

Nitrogen fertilizer is an essential nutrient for rice (Oryza sativa L.), especially, for newly bred 'super' rice cultivars with great yield potential. The effects of nitrogen fertilizer (0, 100, 200, 300, 400 kg N ha-1) on the physicochemical properties of two high yielding 'super' rice Yongyou 2640 and Lianjing 7 were investigated in this study. The application of nitrogen fertilizer affects the structure of rice starch, thus changing its functional properties, which ultimately leads to a change in the quality of both rice cultivars. There were dose effects of nitrogen fertilizer on grain quality. Grain quality was improved under moderate nitrogen inputs (100 & 200 kg N ha-1), but deteriorated at excessive nitrogen levels (300 & 400 kg N ha-1). With moderate N application, starch granule size increased and the surface of starch granule became smoother; there were higher proportion of short branch-chain of amylopectin and lower proportion of long branch-chain of amylopectin with low relative crystallinity, lower degree of order of structure and higher content of amorphous structure at the outer region of the starch granules; peak viscosity, hot viscosity, breakdown value were increased while setback and pasting temperature were decreased; gelatinization temperature, gelatinization enthalpy, retrogradation enthalpy, retrogradation percentage, hardness were decreased while viscosity were increased. At excessive nitrogen inputs, the grain quality was deteriorated and the opposite results of structure and physicochemical properties of rice starch were observed. These results indicate that nitrogen fertilizer significantly affected the structure and physicochemical properties of rice starch, and appropriate fertilization would improve rice grain quality.

A DNAH17 missense variant causes flagella destabilization and asthenozoospermia.

Asthenozoospermia is a common cause of male infertility, but its etiology remains incompletely understood. We recruited three Pakistani infertile brothers, born to first-cousin parents, displaying idiopathic asthenozoospermia but no ciliary-related symptoms. Whole-exome sequencing identified a missense variant (c.G5408A, p.C1803Y) in DNAH17, a functionally uncharacterized gene, recessively cosegregating with asthenozoospermia in the family. DNAH17, specifically expressed in testes, was localized to sperm flagella, and the mutation did not alter its localization. However, spermatozoa of all three patients showed higher frequencies of microtubule doublet(s) 4-7 missing at principal piece and end piece than in controls. Mice carrying a homozygous mutation (Dnah17M/M) equivalent to that in patients recapitulated the defects in patients' sperm tails. Further examinations revealed that the doublets 4-7 were destabilized largely due to the storage of sperm in epididymis. Altogether, we first report that a homozygous DNAH17 missense variant specifically induces doublets 4-7 destabilization and consequently causes asthenozoospermia, providing a novel marker for genetic counseling and diagnosis of male infertility.

Preparation of pH-sensitive and antioxidant packaging films based on κ-carrageenan and mulberry polyphenolic extract.

In this study, antioxidant and pH-sensitive κ-carrageenan based films were developed by incorporating different amounts of mulberry polyphenolic extract (MPE). Due to abundant anthocyanin content, MPE showed pH-sensitive property with solution color changed from red to purple and final gray when pH value increased from 2 to 13. When MPE was incorporated into κ-carrageenan film, the composite films presented blue color. Notably, the incorporation of 2 and 4 wt% of MPE could significantly increase the thickness, tensile strength, thermal stability, antioxidant activity and pH-sensitive property of κ-carrageenan film. However, the moisture content, water vapor permeability, UV-vis light transmittance and elongation at break were greatly reduced when 2 and 4 wt% of MPE were incorporated. In addition, κ-carrageenan-MPE films exhibited heterogeneous and rougher surfaces as compared with κ-carrageenan film. The existence of intermolecular interactions between MPE and κ-carrageenan matrix was confirmed by infrared spectroscopy and X-ray diffraction. When applied to monitor the freshness of milk, κ-carrageenan-MPE films showed evident color changes as milk deteriorated after storage at 40 °C for 8 h. Our results suggested that κ-carrageenan-MPE films could be used as novel active and intelligent food packaging materials.

Genetic analysis of the relation between IL2RA/IL2RB and rheumatoid arthritis risk.

BACKGROUND: The biological mechanisms driving disease chronicity in rheumatoid arthritis (RA) are largely unidentified. Therefore, we aimed to determine genetic risk factors for RA. METHODS: In this case-control study, which includes samples from 499 patients and 507 healthy controls, six single-nucleotide polymorphisms (SNPs) in interleukin-2 receptor subunit alpha (IL2RA) and IL2RB were selected. Genotyping was performed using the Agena MassARRAY platform, and the statistical analyses were performed using the chi-squared and Fisher's exact tests, genetic model analysis, and haplotype analysis. RESULT: In the allele model, using the chi-squared test, the result showed that rs791588 in IL2RA was associated with a decreased RA risk (odds ratios [OR] = 0.74, 95% confidence intervals [CI] = 0.62-0.89, p = 0.0014) after adjusting for age and gender. In the genetic model, logistic regression analyses revealed that rs791588 was associated with a decreased risk of RA under the codominant model, dominant model, recessive model, and log-additive model. Stratification analysis revealed that two SNPs (rs791588 and rs2281089) were significantly associated with a reduced RA risk in an allele and genetic model after stratification by gender or age (p < 0.05). In addition, the haplotypes "Crs12569923 Grs791588 " and "Crs12569923 Trs791588 " of IL2RA was associated with an increased risk of RA adjusted by age and gender (OR = 1.35, 95% CI: 1.12-1.64, p = 0.0016; OR = 1.24, 95% CI: 1.03-1.48, p = 0.021). CONCLUSION: This finding indicates that the inherited altered genetic constitution at IL2RA may predispose to a less destructive course of RA.

A novel electrochemical mast cell-based paper biosensor for the rapid detection of milk allergen casein.

Developing low-cost, portable and simple analysis tools is of vital importance for food safety point-of-care testing. Therefore, herein, a new low-cost, simple to fabricate, disposable, electrochemical mast cell-based paper sensor is proposed and developed to sensitively determine the major milk allergen casein. Then, a graphene (GN)/carbon nanofiber (CN)/ Gelatin methacryloyl (GelMA) composite material with high conductivity and good biocompatibility was modified on the cell-based paper sensor to improve the electrical conductivity and provide a sensing recognition interface for the immobilization of rat basophilic leukemia (RBL-2H3) mast cells. The cyclic voltammetry and differential pulse voltammetry measurement of the mast cells in the paper sensor revealed an irreversible anodic peak, whose peak current is proportional to the number of cells in the range from 1 × 102 to 1 × 108 cells/mL. For the milk allergen detection tests, mast cells exposed to the casein caused a significant reduction in the current signal, displaying an inverse dose-dependent relationship. The developed cell sensor exhibited a range of linearity between 1 × 10-7 and 1 × 10-6 g/mL of casein with a detection limit of 3.2 × 10-8 g/mL and a great reproducibility and selectivity. The electrochemical responses obtained using the cell-based paper sensor were well consistent with the conventional detection assay, with good stability and reproducibility. Therefore, a simple and novel electrochemical method for food allergens detection was developed, demonstrating its potential application in the food safety determination and evaluation.

A novel and simple cell-based electrochemical biosensor for evaluating the antioxidant capacity of Lactobacillus plantarum strains isolated from Chinese dry-cured ham.

The analysis of antioxidants in foodstuffs has become an active area of research, leading to the recent development of numerous methods for assessing antioxidant capacity. Here we described the fabrication and validation of a novel and simple cell-based electrochemical biosensor for this purpose. The biosensor is used to assess the antioxidant capacity of cell-free extracts from Lactobacillus plantarum strains isolated from Chinese dry-cured ham. The biosensor relies on the determination of cellular reactive oxygen species (ROS) (the flux of H2O2 released from RAW 264.7 macrophage cells) to indirectly assess changes in intracellular oxidative stress level as influenced by L. plantarum strains. A one-step acidified manganese dioxide (a-MnO2) modified gold electrode (GE) was used to immobilize RAW 264.7 macrophage cells, which were then encapsulated in a 3D cell culture system consisting of alginate/ graphene oxide (NaAlg/GO). The biosensor exhibited a rapid and sensitive response for the detection of H2O2 released from RAW264.7 cells. The detection limit was 0.02µM with a linear response from 0.05µM to 0.85µM and the biosensor was shown to have good stability and outstanding repeatability. This technique was then used for evaluating the antioxidant ability of extracts from L. plantarum NJAU-01. According to the electrochemical investigations and assays of SEM, TEM, and ROS, these cell-free extracts effectively reduced the oxidative stress levels in RAW264.7 cells under external stimulation. Extracts from L. plantarum strains at a dose of 1010CFU/mL showed the highest antioxidant activities with a relative antioxidant capacity (RAC) rate of 88.94%. Hence, this work provides a simple and efficient electrochemical biosensing platform based on RAW264.7 cells for fast, sensitive and quantitative assessment of antioxidant capacity of L. plantarum strains. The method demonstrates its potential for rapid screening for evaluating antioxidant properties of samples.

A novel screen-printed mast cell-based electrochemical sensor for detecting spoilage bacterial quorum signaling molecules (N-acyl-homoserine-lactones) in freshwater fish.

A novel screen-printed cell-based electrochemical sensor was developed to assess bacterial quorum signaling molecules, N-acylhomoserine lactones (AHLs). Screen-printed carbon electrode (SPCE), which possesses excellent properties such as low-cost, disposable and energy-efficient, was modified with multi-walled carbon nanotubes (MWNTs) to improve electrochemical signals and enhance the sensitivity. Rat basophilic leukemia (RBL-2H3) mast cells encapsulated in alginate/graphene oxide (NaAgl/GO) hydrogel were immobilized on the MWNTs/SPCE to serve as recognition element. Electrochemical impedance spectroscopy (EIS) was employed to record the cell impedance signal as-influenced by Pseudomonas aeruginosa quorum-sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC12-HSL). Experimental results show that 3OC12-HSL caused a significant decrease in cell viability in a dose dependent manner. The EIS value decreased with concentrations of 3OC12-HSL in the range of 0.1-1µM, and the detection limit for 3OC12-HSL was calculated to be 0.094µM. These results were confirmed via cell viability, SEM, TEM analysis. Next, the sensor was successfully applied to monitoring the production of AHLs by spoilage bacteria in three different freshwater fish juice samples which efficiently proved the practicability of this cell based method. Therefore, the proposed cell sensor may serve as an innovative and effective approach to the measurement of quorum signaling molecule and thus provides a new avenue for real-time monitoring the spoilage bacteria in freshwater fish production.

Preliminary study on an innovative, simple mast cell-based electrochemical method for detecting foodborne pathogenic bacterial quorum signaling molecules (N-acyl-homoserine-lactones).

This paper reports the a novel and simple mast cell-based electrochemical method for detecting of bacterial quorum signaling molecules, N-acylhomoserine lactones (AHLs), which can be utilized to preliminarily evaluate the toxicity of food-borne pathogenic bacteria. Rat basophilic leukemia (RBL-2H3) mast cells encapsulated in alginate/graphene oxide hydrogel were immobilized on a gold electrode, while mast cells as recognition elements were cultured in a 3D cell culture system. Electrochemical impedance spectroscopy (EIS) was utilized to record the cell impedance signal as-influenced by Pseudomonas aeruginosa quorum-sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC12-HSL). The results indicated that cellular activities such as cell viability, apoptosis, intracellular calcium, and degranulation were markedly influenced by the AHLs. Importantly, the exposure of 3OC12-HSL to mast cells induced a marked decrease in the electrochemical impedance signal in a dose-dependent manner. The detection limit for 3OC12-HSL was 0.034µM with a linear range of 0.1-1µM. These results were confirmed via conventional cell assay and transmission electron microscope (TEM) analysis. Altogether, the proposed method appears to be an innovative and effective approach to the quantitative measurement of Gram-negative bacterial quorum signaling molecules; to this effect, it also may serve as a primary evaluation of the cytotoxicity of food-borne pathogens.