Rapid Detection of Uropathogens Using an Integrated Multiplex Digital Nucleic Acid Detection Assay Powered by a Digital-to-Droplet Microfluidic Device.

The digital nucleic acid detection assay features the capability of absolute quantitation without the need for calibration, thereby facilitating the rapid identification of pathogens. Although several integrated digital nucleic acid detection techniques have been developed, there are still constraints in terms of automation and analysis throughput. To tackle these challenges, this study presents a digital-to-droplet microfluidic device comprising a digital microfluidics (DMF) module at the bottom and a droplet microfluidics module at the top. Following sample introduction, the extraction of nucleic acid and the dispensation of nucleic acid elution for mixing with the multiple amplification reagents are carried out in the DMF module. Subsequently, the reaction droplets are transported to the sample inlet of the droplet microfluidic module via a liquid outlet, and then droplet generation in four parallel units within the droplet microfluidics module is actuated by negative pressure generated by a syringe vacuum. The digital-to-droplet microfluidic device was employed to execute an integrated multiplex digital droplet nucleic acid detection assay (imDDNA) incorporating loop-mediated isothermal amplification (LAMP). This assay was specifically designed to enable simultaneous detection of four uropathogens, namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterococcus faecalis. The entire process of the imDDNA is completed within 75 min, with a detection range spanning 5 orders of magnitude (9.43 × 10-2.86 × 104 copies µL-1). The imDDNA was employed for the detection of batched clinical specimens, showing a consistency of 91.1% when compared with that of the conventional method. The imDDNA exhibits simplicity in operation and accuracy in quantification, thus offering potential advantages in achieving rapid pathogen detection.

TMEM184B promotes proliferation, migration and invasion, and inhibits apoptosis in hypopharyngeal squamous cell carcinoma.

Several members of the transmembrane protein family are associated with the biological processes of human malignancies; however, the expression pattern and biological function of one family member, TMEM184B, in hypopharyngeal squamous cell carcinoma (HPSCC) are not fully understood. The expression between HPSCC tumours and adjacent normal tissues was determined by the Immunohistochemistry (IHC). A bioinformatics analysis was performed to verify the expression pattern of TMEM184B in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Furthermore, in vitro assays on cell proliferation, invasion, migration and in vivo experiments on tumour growth and apoptosis of TMEM184B in HPSCC were performed. We found that the HPSCC tissues had a significantly higher expression of TMEM184B than the adjacent normal tissues. Bioinformatics analysis confirmed the different expression of TMEM184B expression in HPSCC. Furthermore, in vitro and in vivo experiments demonstrated that TMEM184B promotes HPSCC cell growth, cell invasion and migration in FaDu cells, whereas flow cytometry assay showed that TMEM184B inhibited cell apoptosis. Our study revealed for the first time that TMEM184B might serve an oncogenic function in HPSCC and could be a potential diagnostic biomarker and therapeutic target for HPSCC.

Structure and properties of gelatin edible film modified using oxidized poly(2-hydroxyethyl acrylate) with multiple aldehyde groups.

BACKGROUND: Pure gelatin film usually exhibits characteristics of being brittle and hydrophilic, which limit its wide use in food packing fields. In this study gelatin/oxidized poly(2-hydroxyethylacrylate) (G/OP) composite films were prepared using casting techniques, the aim of this research was to investigate the effects of OP on the structures and properties of the G/OP composite films. RESULTS: The Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy results indicated that the G/OP films retained their original secondary structure and random coiled conformation. However, the surface and cross-sectional morphologies of the G/OP films were rougher than those of pure gelatin films, cracks and agglomerates appeared with increasing OP dosage. The remarkable transparency of the G/OP film at 280 nm indicated excellent ultraviolet (UV) light barrier properties of the film, which inhibited UV-light-induced food oxidation. Moreover, the addition of OP decreased the water content and water solubility and considerably increased the water contact angle of pure gelatin films from 78.8° to 116.2° (a maximum increase of 37.5°). This suggested that OP modification improved the hydrophobicity of gelatin films. Furthermore, the inclusion of OP significantly promoted the flexibility of gelatin films, thereby improving their brittleness. CONCLUSIONS: The UV light barrier properties, hydrophobicity, and flexibility of gelatin films were improved via OP modification, thus the produced G/OP composite films have the potential to be used in food packaging. © 2022 Society of Chemical Industry.

Encapsulation of Zanthoxylum bungeanum essential oil to enhance flavor stability and inhibit lipid oxidation of Chinese-style sausage.

BACKGROUND: Zanthoxylum bungeanum essential oil (ZBEO) is a popular seasoning, commonly used in the food industry. It contains many easily degraded and highly volatile bioactive substances. Control of the stability of the bioactive substances in ZBEO is therefore very important in the food industry. RESULTS: In this study, microencapsulation was applied to improve ZBEO stability. The key parameters for microcapsule preparation were optimized by the Box-Behnken design method, and the optimum conditions were as follows: ratio of core to wall, 1:8; ratio of hydroxypropyl-α-cyclodextrin (HPCD) to soy protein isolate (SPI), 4; total solids content, 12%; and homogenization speed, 12 000 rpm. Antioxidant experiments have indicated that tea polyphenols (TPPs) effectively inhibited hydroxy-α-sanshool degradation in ZBEO microcapsules. Application of ZBEO microcapsules in Chinese-style sausage effectively inhibited lipid oxidation in sausages and protected hydroxy-α-sanshool and typical volatiles from volatilization and degradation during sausage storage. CONCLUSION: The results suggested that ZBEO microencapsulation is an effective strategy for improving the stability of its bioactive components and flavor ingredients during food processing. © 2022 Society of Chemical Industry.

Effect of cooking methods on the edible, nutritive qualities and volatile flavor compounds of rabbit meat.

BACKGROUND: Rabbit meat is a good edible meat source with high nutritional values. Cooking has a significant impact on the edible properties, nutritional qualities and flavor characteristics of meat. Studying the effect of cooking methods on rabbit meat qualities could encourage more understanding and acceptance of rabbit meat by consumers, and could also provide some reference for rabbit meat processing. Therefore, the effects of boiling, sous-vide cooking, steaming, microwaving, roasting, frying and pressure cooking on the edible, nutritive and volatile qualities of rabbit meat were investigated. RESULTS: The sous-vide cooked rabbit meat sample showed higher moisture content, water-holding capacity and lower cooking losses than other samples, but the results of roasted rabbit meat sample were the opposite, and scanning electron microscopy observations also verified the results. There was no significant difference in 2-thiobarbituric acid reactive substance (TBARS) value in the cooked samples except for roasting. Microwaving, roasting and frying exhibited stronger antioxidant activity than the other cooked samples after in vitro digestion. A total of 38 volatiles were identified in the cooked meat samples, and the samples were well divided into four groups by principal component analysis, and 13 volatiles were considered discriminatory variables for the cooked rabbit meat. CONCLUSION: The physicochemical characteristics of cooked meat differed significantly between the processing methods. Roasted meat showed lower TBARS value and stronger antioxidant activity after simulated digestion compared to the other meats. However, pressure cooked meat detected the most volatile components while roasting the least. © 2022 Society of Chemical Industry.

Microgel Single-Cell Culture Arrays on a Microfluidic Chip for Selective Expansion and Recovery of Colorectal Cancer Stem Cells.

Cancer stem cells (CSCs) are rare and lack definite biomarkers, necessitating new methods for a robust expansion. Here, we developed a microfluidic single-cell culture (SCC) approach for expanding and recovering colorectal CSCs from both cell lines and tumor tissues. By incorporating alginate hydrogels with droplet microfluidics, a high-density microgel array can be formed on a microfluidic chip that allows for single-cell encapsulation and nonadhesive culture. The SCC approach takes advantage of the self-renewal property of stem cells, as only the CSCs can survive in the SCC and form tumorspheres. Consecutive imaging confirmed the formation of single-cell-derived tumorspheres, mainly from a population of small-sized cells. Through on-chip decapsulation of the alginate microgel, ∼6000 live cells can be recovered in a single run, which is sufficient for most biological assays. The recovered cells were verified to have the genetic and phenotypic characteristics of CSCs. Furthermore, multiple CSC-specific targets were identified by comparing the transcriptomics of the CSCs with the primary cancer cells. To summarize, the microgel SCC array offers a label-free approach to obtain sufficient quantities of CSCs and thus is potentially useful for understanding cancer biology and developing personalized CSC-targeting therapies.

A fully automated microfluidic PCR-array system for rapid detection of multiple respiratory tract infection pathogens.

Rapid and accurate identification of respiratory tract infection pathogens is of utmost importance for clinical diagnosis and treatment, as well as prevention of pathogen transmission. To meet this demand, a microfluidic chip-based PCR-array system, Onestart, was developed. The Onestart system uses a microfluidic chip packaged with all the reagents required, and the waste liquid is also collected and stored on the chip. This ready-to-use system can complete the detection of 21 pathogens in a fully integrated manner, with sample lysis, nucleic acid extraction/purification, and real-time PCR sequentially implemented on the same chip. The entire analysis process is completed within 1.5 h, and the system automatically generates a test report. The lower limit-of-detection (LOD) of the Onestart assay was determined to be 1.0 × 103 copies·mL-1. The inter-batch variation of cycle threshold (Ct) values ranged from 0.08% to 0.69%, and the intra-batch variation ranged from 0.9% to 2.66%. Analytical results of the reference sample mix showed a 100% specificity of the Onestart assay. The analysis of batched clinical samples showed consistency of the Onestart assay with real-time PCR. With its ability to provide rapid, sensitive, and specific detection of respiratory tract infection pathogens, application of the Onestart system will facilitate timely clinical management of respiratory tract infections and effective prevention of pathogen transmission. Onestart, a ready-to-use system, can detect 21 pathogens in a fully integrated manner on a microchip within 1.5 h.

A novel surgical approach for hypopharyngeal carcinoma resection via the paraglottic space.

BACKGROUND: Conservative surgery has proven advantageous in controlling hypopharyngeal squamous cell carcinoma (HSCC) and preserving speech and swallowing function in carefully selected patients, typically with early T-stages diseases. A variety of modified surgical procedures or techniques have been proposed. METHODS: In this study, we present a novel surgical approach for hypopharyngeal carcinoma resection utilizing the paraglottic space. RESULTS: The paraglottic space approach can help expose neoplasms under direct vision and save mucosa during surgery while sufficiently preserving laryngeal function, thus benefiting postoperative swallowing and reducing complications. A large cohort of 426 patients with HSCC underwent surgical treatment at our institution using this approach, demonstrating an overall survival (OS) rate of 52.3% and low incidences of postoperative complications. CONCLUSIONS: This surgical approach can be applied in patients with the lesions that do not involve the paraglottic space.

Complex wall materials of polysaccharide and protein effectively protected numb-taste substance degradation of Zanthoxylum bungeanum.

BACKGROUND: Hydroxyl-sanshools are mainly responsible for the numb taste and biological activities of Zanthoxylum bungeanum, but they show low water solubility, high volatility and easy degradation, which limit their application in the catering and food industries. Thus microcapsules of Z. bungeanum essential oil (ZBEO) were prepared to prevent numb-taste substance attenuation. RESULTS: The complex effects of hydroxypropyl-ß-cyclodextrin (HPCD) with other materials, such as konjac glucomannan octenyl succinate (KGOS), octenyl succinic anhydride-modified starch (OSAS), soy protein isolate (SPI) and gum arabic (GA), on the protection of the main numb-taste substance of ZBEO were investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that ZBEO was successfully encapsulated in the complex wall materials. X-ray diffraction indicated that the loaded essential oil did not affect the crystalline form of the wall material. The stability of the numb-taste substance α-sanshool in the microcapsules prepared with the complex microcapsule wall materials was higher than that in single-wall microcapsules. Storage stability evaluation indicated that microcapsules prepared with a combination of HPCD and SPI showed the greatest effect in maintaining the stability of the main numb-taste substance α-sanshool in ZBEO at room temperature, low pH and in high-salt conditions. CONCLUSION: Complex wall materials of polysaccharide and protein could effectively protect the numb-taste substance degradation of Z. bungeanum during processing and storage. © 2021 Society of Chemical Industry.

Combination of mutagenesis and adaptive evolution to engineer salt-tolerant and aroma-producing yeast for soy sauce fermentation.

BACKGROUND: The moromi fermentation of high-salt liquid-state fermentation (HLF) soy sauce is usually performed in high-brine solution (17-20%, w/w), which decreases the metabolic activity of aroma-producing yeast. To enhance the soy sauce flavors, increasing the salt tolerance of aroma-producing yeasts is very important for HLF soy sauce fermentation. RESULTS: In the present study, atmospheric and room-temperature plasma (ARTP) was first used to mutate the aroma-producing yeast Wickerhamomyces anomalus, and the salt tolerant strains were obtained by selection of synthetic medium with a sodium chloride concentration of 18% (w/w). Furthermore, adaptive laboratory evolution (ALE) was used to improve the salt tolerance of the mutant strains. The results obtained indicated that the combination use of ARTP and ALE markedly increased the NaCl tolerance of the yeast by increasing the cellular accumulation of K+ and removal of cytosolic Na+ , in addition to promoting the production of glycerin and strengthening the integrity of the cell membrane and cell wall. In soy sauce fermentation, the engineered strains improved the physicochemical parameters of HLF soy sauce compared to those produced by the wild-type strain, and the engineered strains also increased the alcohol, acid and aldehyde production, and enriched the types of esters in the soy sauce. CONCLUSION: The results of the present study indicated that the combination of ARTP mutagenesis and ALE significantly improved the salt tolerance of the aroma-producing yeast, and also enhanced the production of volatiles of HLF soy sauce. © 2021 Society of Chemical Industry.

Open Surface Droplet Microfluidic Magnetosensor for Microcystin-LR Monitoring in Reservoir.

Establishing rapid, simple, and in situ detection of microcystin-LR (MC-LR) in drinking water sources is of significant importance for human health. To ease the situation that current methods cannot address, an open surface droplet microfluidic magnetosensor was designed and validated to quantify MC-LR in reservoir water, which is capable of (1) MC-LR isolation via MC-LR antibody-conjugated magnetic beads, (2) parallel and multistep analytical procedures in 15-array power-free and reusable active droplet microfluidic chips, (3) immunoassay incubation and fluorescence excitation within a miniaturized multifunctional 3D-printing optosensing accessory, and (4) signal read-out and data analysis by a user-friendly Android app. The proposed smartphone-based fluorimetric magnetosensor exhibited a low limit of detection of 1.2 × 10-5 µg/L in the range of 10-4 µg/L to 100 µg/L. This integrated and high throughput platform was utilized to draw an MC-LR contamination map for six reservoirs distributed in the Pearl River delta, Guangdong Province. It promises to be a simple and successful quantification method for MC-LR field detection, bringing many benefits to rapid on-site screening.

Screening Therapeutic Agents Specific to Breast Cancer Stem Cells Using a Microfluidic Single-Cell Clone-Forming Inhibition Assay.

Screens of cancer stem cells (CSCs)-specific agents present significant challenges to conventional cell assays due to the difficulty in preparing CSCs ready for drug testing. To overcome this limitation, developed is a microfluidic single-cell assay for screening breast cancer stem cell-specific agents. This assay takes advantage of the single-cell clone-forming capability of CSCs, which can be specifically inhibited by CSC-targeting agents. The single-cell assay is performed on a microfluidic chip with an array of 3840 cell-capturing units; the single-cell arrays are easily formed by flowing a cell suspension into the microchip. Achieved is a single cell-capture rate of ≈60% thus allowing more than 2000 single cells to be analyzed in a single test. Over long-term suspension culture, only a minority of cells survive and form tumorspheres. The clone-formation rate of MCF-7, MDA-MB-231, and T47D cells is 1.67%, 5.78%, and 5.24%, respectively. The clone-forming inhibition assay is conducted by exposing the single-cell arrays to a set of anticancer agents. The CSC-targeting agents show complete inhibition of single-cell clone formation while the nontargeting ones show incomplete inhibition effects. The resulting microfluidic single-cell assay with the potential to screen CSC-specific agents with high efficiency provides new tools for individualized tumor therapy.

Comparative review and the recent progress in detection technologies of meat product adulteration.

Meat adulteration, mainly for the purpose of economic pursuit, is widespread and leads to serious public health risks, religious violations, and moral loss. Rapid, effective, accurate, and reliable detection technologies are keys to effectively supervising meat adulteration. Considering the importance and rapid advances in meat adulteration detection technologies, a comprehensive review to summarize the recent progress in this area and to suggest directions for future progress is beneficial. In this review, destructive meat adulteration technologies based on DNA, protein, and metabolite analyses and nondestructive technologies based on spectroscopy were comparatively analyzed. The advantages and disadvantages, application situations of these technologies were discussed. In the future, determining suitable indicators or markers is particularly important for destructive methods. To improve sensitivity and save time, new interdisciplinary technologies, such as biochips and biosensors, are promising for application in the future. For nondestructive techniques, convenient and effective chemometric models are crucial, and the development of portable devices based on these technologies for onsite monitoring is a future trend. Moreover, omics technologies, especially proteomics, are important methods in laboratory detection because they enable multispecies detection and unknown target screening by using mass spectrometry databases.

[Bladder outlet obstruction index alone is not reliable for the diagnosis of benign prostate hyperplasia].

OBJECTIVE: To evaluate the clinical application value of the bladder outlet obstruction index (BOOI) in the diagnosis of BPH. METHODS: We retrospectively analyzed the urodynamic parameters and BOOI of 199 cases of BPH diagnosed from July 2016 to September 2018, which were divided into a BOO (n = 119), a suspected BOO (n = 39) and a non-BOO group (n = 41) based on the BOOI. We obtained the prostate volume (PV), IPSS, IPSS-voiding symptom score (IPSS-VS), quality of life score (QOL), maximum urinary flow rate (Qmax) and postvoid residual urine volume (PVR) from the patients, compared them among the three groups and analyzed their correlation to BOOI using Pearson's linear correlation analysis. RESULTS: No statistically significant differences were observed in age (P = 0.195), PSA (P = 0.380), IPSS (P = 0.380), IPSS-VS (P = 0.380), QOL (P = 0.380), Qmax (P = 0.380) and PVR (P = 0.912) among the three groups of patients, but PV was remarkably larger in the BOO than in the suspected BOO and non-BOO groups (ï¼»58.8 ± 30.0ï¼½ vs ï¼»49.8 ± 33.9ï¼½ and ï¼»45.5 ± 26.0ï¼½ ml, P = 0.031). Pearson's linear correlation analysis showed that BOOI was not correlated significantly to IPSS (r = －0.020, P = 0.778), IPSS-VS (r= －0.013, P = 0.853), QOL (r = －0.107, P = 0.132), Qmax (r = －0.130, P = 0.066) or PVR (r = －0.056, P = 0.433), nor obviously to PV (|r| = 0.178<0.4) though with P = 0.012. CONCLUSIONS: BOOI is not significantly correlated to PV, IPSS, IPSS-VS, QOL, Qmax or PVR, and therefore BOO cannot be diagnosed exclusively with BOOI.

Directly mining a fungal thermostable α-amylase from Chinese Nong-flavor liquor starter.

BACKGROUND: Chinese Nong-flavor (NF) liquor is continuously and stably produced by solid-state fermentation technology for 1000 years, resulting in enrichment of special microbial community and enzymes system in its starter. Based on traditional culture-dependent methods, these functional enzymes are hardly obtained. According to our previous metatranscriptomic analysis, which identifies plenty of thermostable carbohydrate-active enzymes in NF liquor starter, the aim of this study is to provide a direct and efficient way to mine these thermostable enzymes. RESULTS: In present study, an alpha-amylase (NFAmy13A) gene, which showed the highest expression level of enzymes in starch degradation at high temperature stage (62 °C), was directly obtained by functional metatranscriptomics from Chinese Nong-flavor liquor starter and expressed in Pichia pastoris. NFAmy13A had a typical signal peptide and shared the highest sequence identity of 64% with α-amylase from Aspergillus niger. The recombinant enzyme of NFAmy13A showed an optimal pH at 5.0-5.5 and optimal temperature at 60 °C. NFAmy13A was activated and stabilized by Ca2+, and its half-lives at 60 and 70 °C were improved significantly from 1.5 and 0.4 h to 16 and 0.7 h, respectively, in the presence of 10 mM CaCl2. Meanwhile, Hg2+, Co2+ and SDS largely inhibited its activity. NFAmy13A showed the maximum activity on amylopectin, followed by various starches, amylose, glycogen, and pullulan, and its specificity activity on amylopectin was 200.4 U/mg. Moreover, this α-amylase efficiently hydrolyzed starches (from corn, wheat, and potato) at high concentrations up to 15 mg/ml. CONCLUSIONS: This study provides a direct way to mine active enzymes from man-made environment of NF liquor starter, by which a fungal thermostable α-amylase (NFAmy13A) is successfully obtained. The good characteristics of NFAmy13A in degrading starch at high temperature are consistent with its pivotal role in solid-state fermentation of NF liquor brewing. This work would stimulate mining more enzymes from NF liquor starter and studying their potentially synergistic roles in NF liquor brewing, thus paving the way toward the optimization of liquor production and improvement of liquor quality in future.

Konjac glucomannan octenyl succinate (KGOS) as an emulsifier for lipophilic bioactive nutrient encapsulation.

BACKGROUND: Konjac glucomannan octenyl succinate (KGOS) has excellent emulsification properties and can potentially be used in the food industry as an emulsifier, stabilizer and microcapsule wall material. In the present study, the in vitro digestion properties and emulsification capability and stability of KGOS were studied to evaluate the transport and encapsulation characteristics of KGOS with insoluble bioactive nutrients. RESULTS: Confocal scanning laser microscopy (CSLM) suggested that oil droplets could be encapsulated by KGOS into regular spheres. In vitro digestion properties showed that KGOS is effective for colon-targeted transport. ß-Carotene was selected as a representative lipophilic bioactive compound to evaluate the emulsification characteristics of KGOS. The loading capacity of the 0.4 mg mL-1 KGOS solution for ß-carotene was 3.26%, and transmission electron microscopy suggested that the self-aggregate particles of KGOS/ß-carotene (KGOSC) were more uniform than KGOS. With a composition of 0.03% ß-carotene, 0.3% KGOS and 10% medium-chain triglycerides, the emulsification yield of the KGOSC nanoemulsion was more than 95%. After 30 days of storage, the particle size and polydispersity index of the KGOSC nanoemulsion were less than 5 nm and 0.5, respectively, and the sensitivity of KGOSC nanoemulsions to storage conditions decreased in the order temperature, oxygen and light. CONCLUSION: The results of this study suggested that KGOS is a good potential emulsifier and stabilizer for lipophilic bioactive nutrient encapsulation. © 2018 Society of Chemical Industry.

Upregulation of the long noncoding RNA UCA1 affects the proliferation, invasion, and survival of hypopharyngeal carcinoma.

BACKGROUND: Several long noncoding RNAs (lncRNAs) are involved in oncogenesis. METHODS AND RESULTS: Our microarray analysis showed that numerous lncRNAs are dysregulated in hypopharyngeal squamous cell carcinoma (HSCC) tumor tissues as compared with normal tissues. Among those lncRNAs, urothelial carcinoma-associated 1 (UCA1) has been found to have an oncogenic role in HSCC. We confirmed the upregulation of UCA1 in HSCC by assessing its expression levels in a cohort of 53 patient tumors and paired non-tumor samples. In addition, we found that high UCA1 expression was significantly associated with advanced T category, late clinical stage, greater lymphatic invasion, and worse prognosis. Furthermore, in vitro experiments demonstrated that UCA1 functioned as an oncogene by promoting the proliferation and invasion and preventing the apoptosis of HSCC cells. CONCLUSIONS: Taken together, our findings for the first time identify the role of UCA1 as a tumor promoter and a pro-metastatic factor in HSCC, demonstrating that UCA1 is a potential prognostic biomarker and therapeutic target in HSCC.

Orthogonal Screening of Anticancer Drugs Using an Open-Access Microfluidic Tissue Array System.

Screening for potential drug combinations presents significant challenges to the current microfluidic cell culture systems, due to the requirement of flexibility in liquid handling. To overcome this limitation, we present here an open-access microfluidic tissue array system specifically designed for drug combination screening. The microfluidic chip features a key structure in which a nanoporous membrane is sandwiched by a cell culture chamber array layer and a corresponding media reservoir array layer. The microfluidic approach takes advantage of the characteristics of the nanoporous membrane: on one side, this membrane permits the flow of air but not liquid, thus acting as a flow-stop valve to enable automatic cell distribution; on the other side, it allows diffusion-based media exchange and thus mimics the endothelial layer. In synergy with a liquid-transferring platform, the open-access microfluidic system enables complex multistep operations involving long-term cell culture, medium exchange, multistep drug treatment, and cell-viability testing. By using the microfluidic protocol, a 10 × 10 tissue array was constructed in 90 s, followed by schedule-dependent drug testing. Morphological and immunohistochemical assays indicated that the resultant tumor tissue was faithful to that in vivo. Drug-testing assays showed that the incorporation of the nanoporous membrane further decreased killing efficacy of the anticancer agents, indicating its function as an endothelial layer. Robustness of the microfluidic system was demonstrated by implementing a three-factor, three-level orthogonal screening of anticancer drug combinations, with which 67% of the testing (9 vs. 27) was saved. Experimental results demonstrated that the microfluidic tissue system presented herein is flexible and easy-to-use, thus providing an ideal tool for performing complex multistep cell assays with high efficiencies.

Simultaneous Identification and Antimicrobial Susceptibility Testing of Multiple Uropathogens on a Microfluidic Chip with Paper-Supported Cell Culture Arrays.

A microfluidic chip was developed for one-step identification and antimicrobial susceptibility testing (AST) of multiple uropathogens. The polydimethylsiloxane (PDMS) microchip used had features of cell culture chamber arrays connected through a sample introduction channel. At the bottom of each chamber, a paper substrate preloaded with chromogenic media and antimicrobial agents was embedded. By integrating a hydrophobic membrane valve on the microchip, the urine sample can be equally distributed into and confined in individual chambers. The identification and AST assays on multiple uropathogens were performed by combining the spatial resolution of the cell culture arrays and the color resolution from the chromogenic reaction. The composite microbial testing assay was based on dynamic changes in color in a serial of chambers. The bacterial antimicrobial susceptibility was determined by the lowest concentration of an antimicrobial agent that is capable of inhibiting the chromogenic reaction. Using three common uropathogenic bacteria as test models, the developed microfluidic approach was demonstrated to be able to complete the multiple colorimetric assays in 15 h. The accuracy of the microchip method, in comparison with that of the conventional approach, showed a coincidence of 94.1%. Our data suggest this microfluidic approach will be a promising tool for simple and fast uropathogen testing in resource-limited settings.

Enhancement of Pork Jerky Using Co-cultures of Lactobacillus bulgaricus and Angel Yeast.

Strains of Lactobacillus bulgaricus and Angel Yeast were combined to ferment raw pork and make pork jerky. After fermentation, the jerky was dried and then tested for sensory evaluation, pH and free amino acid content. The results showed that the optimal conditions for fermentation using L. bulgaricus and Angel Yeast were: a pH of 6.5, a 1:1 (v/v) ratio of L. bulgaricus to Angel Yeast, a fermentation time of 42 h and temperature of 25 °C. The results showed that the pork jerky fermented with the combined strains was not very sour which was close to the pH of 7.0 and had a higher free amino acid content which was more than 68.3 mg/100 g compared with the pork jerky fermented by either L. bulgaricus or Angel Yeast alone. Overall, the results demonstrate that fermentation of raw pork with combined strains of L. bulgaricus and Angel Yeast improves the quality and flavor of pork jerky.