Pulmonary delivery of nano-particles for lung cancer diagnosis and therapy: Recent advances and future prospects.

Although our understanding of lung cancer has significantly improved in the past decade, it is still a disease with a high incidence and mortality rate. The key reason is that the efficacy of the therapeutic drugs is limited, mainly due to insufficient doses of drugs delivered to the lungs. To achieve precise lung cancer diagnosis and treatment, nano-particles (NPs) pulmonary delivery techniques have attracted much attention and facilitate the exploration of the potential of those in inhalable NPs targeting tumor lesions. Since the therapeutic research focusing on pulmonary delivery NPs has rapidly developed and evolved substantially, this review will mainly discuss the current developments of pulmonary delivery NPs for precision lung cancer diagnosis and therapy. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Respiratory Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Value of faecal exfoliated cells in colorectal tumour screening using SDC2 methylation test.

BACKGROUND: This study aimed to evaluate the diagnostic value of a non-invasive methylation gene test in clinical colorectal tumour screening. METHOD: The quantitative methylation-specific PCR technique was used to detect faecal methylated syndecan-2 (mSDC2) in patients who received the screening of colorectal cancer (CRC).To evaluate the positive predictive value (PPV) of mSDC2 in patients with colorectal cancer, advanced adenoma (AA), and colorectal tumor (CRN) in risk factor stratification. RESULTS: The PPV of CRC, CRC + AA and CRN in male patients were 28.03%, 43.55% and 56.24%, respectively, which were higher than female patients. The positive detection rate of mSDC2 and the PPV of CRC gradually increased with age; The PPV in patients aged over 80 years was up to 78.05%, which was more significant than in younger patients with CRC. The PPV of CRC, AA and CRN were 37.10%, 11.80% and 63.37%, respectively. mSDC2 has a high detection rate of 85-100% in AA with intramucosal carcinoma alone or in combination with severe atypical hyperplasia or villous adenoma. CONCLUSION: The mSDC2 test has a higher PPV in patients with colorectal cancer and colorectal adenoma (AD), especially in high-risk groups over 50 years of age, and may help in the early diagnosis of colorectal tumours in the future.

Glycerol-weighted chemical exchange saturation transfer nanoprobes allow 19F/1H dual-modality magnetic resonance imaging-guided cancer radiotherapy.

Recently, radiotherapy (RT) has entered a new realm of precision cancer therapy with the introduction of magnetic resonance (MR) imaging guided radiotherapy systems into the clinic. Nonetheless, identifying an optimized radiotherapy time window (ORTW) is still critical for the best therapeutic efficacy of RT. Here we describe pH and O2 dual-sensitive, perfluorooctylbromide (PFOB)-based and glycerol-weighted chemical exchange saturation transfer (CEST) nano-molecular imaging probes (Gly-PFOBs) with dual fluorine and hydrogen proton based CEST MR imaging properties (19F/1H-CEST). Oxygenated Gly-PFOBs ameliorate tumor hypoxia and improve O2-dependent radiotherapy. Moreover, the pH and O2 dual-sensitive properties of Gly-PFOBs could be quantitatively, spatially, and temporally monitored by 19F/1H-CEST imaging to optimize ORTW. In this study, we describe the CEST signal characteristics exhibited by the glycerol components of Gly-PFOBs. The pH and O2 dual-sensitive Gly-PFOBs with19F/1H-CEST MR dual-modality imaging properties, with superior therapeutic efficacy and biosafety, are employed for sensitive imaging-guided lung cancer RT, illustrating the potential of multi-functional imaging to noninvasively monitor and enhance RT-integrated effectiveness.

Controlled Release of Hydrogen-Carrying Perfluorocarbons for Ischemia Myocardium-Targeting 19 F MRI-Guided Reperfusion Injury Therapy.

Hydrogen gas is recently proven to have anti-oxidative and anti-inflammation effects on ischemia-reperfusion injury. However, the efficacy of hydrogen therapy is limited by the efficiency of hydrogen storage, targeted delivery, and controlled release. In this study, H2 -PFOB nanoemulsions (NEs) is developed with high hydrogen loading capacity for targeted ischemic myocardium precision therapy. The hydrogen-carrying capacity of H2 -PFOB NEs is determined by gas chromatography and microelectrode methods. Positive uptake of H2 -PFOB NEs in ischemia-reperfusion myocardium and the influence of hydrogen on 19 F-MR signal are quantitatively visualized using a 9.4T MR imaging system. The biological therapeutic effects of H2 -PFOB NEs are examined on a myocardial ischemia-reperfusion injury mouse model. The results illustrated that the developed H2 -PFOB NEs can efficaciously achieve specific infiltration into ischemic myocardium and exhibit excellent antioxidant and anti-inflammatory properties on myocardial ischemia-reperfusion injury, which can be dynamically visualized by 19 F-MR imaging system. Moreover, hydrogen burst release induced by low-intensity focused ultrasound (LIFU) irradiation further promotes the therapeutic effect of H2 -PFOB NEs with a favorable biosafety profile. In this study, the potential therapeutic effects of H2 -PFOB NEs is fully unfolded, which may hold great potential for future hydrogen-based precision therapeutic applications tailored to ischemia-reperfusion injury.

Group B Streptococcus infection-induced ovarian vein thrombosis identified during cesarean section: A case report and a literature review.

RATIONALE: Ovarian vein thrombosis (OVT) is a rare yet potentially life-threatening condition associated with thromboembolic events. Group B Streptococcus (GBS) is a type of ß-hemolytic Gram-positive bacterium known for asymptomatic colonization in the lower genital and gastrointestinal tracts. Here we reported a 35-year-old multiparous woman with gestational diabetes who suffered from placental abruption, stillbirth, OVT, septic shock, and renal failure due to severe GBS infection. PATIENT CONCERNS: A 35-year-old woman with gestational diabetes presented with acute and sustained lower abdominal cramping, vaginal bleeding, and fever at 35 gestational weeks. DIAGNOSES: Based on preoperative ultrasound and intraoperative findings, the patient was diagnosed with placental abruption, intrauterine fetal demise, and right OVT. GBS was cultured from the amniotic fluid obtained during cesarean section. INTERVENTIONS: The patient underwent a right adnexectomy during a cesarean section and received intravenous antibiotics. Subsequently, an ultrasound-guided uterine curettage was performed due to recurrent fever. OUTCOMES: After a prolonged course of intravenous antibiotics for over a month, the patient recovered and was discharged from the hospital. LESSONS: This case underscores the need for early initiation of anticoagulant protocols in cases of OVT, particularly when GBS infection is identified as a predisposing factor. Further research and awareness are warranted to better understand the relationship between GBS infection and OVT and to optimize management strategies in such cases.

[Etiology and related clinical indicators of liver failure: an analysis of 3-year case data of Wuxi designated hospital for treatment of liver failure].

OBJECTIVE: To analyze the characteristics of etiology and clinical indicators of hepatitis B virus (HBV) and non-HBV liver failure, and to evaluate their potential roles in reflecting disease outcomes. METHODS: The clinical data of 369 patients with liver failure admitted to the intensive care unit (ICU) of the Fifth People's Hospital of Wuxi which was the designated hospital for treatment of liver failure from January 2018 to December 2020 were retrospectively analyzed. The classification and comparison of etiology of non-HBV and HBV liver failure patients were performed according to the Guidelines on the Diagnosis and Treatment of Liver Failure (2018 edition). The indicators of liver failure related etiologies, including gender, age, anticoagulant enzyme III (AT III), total bilirubin (TBil), length of ICU stay, hepatic encephalopathy, underlying disease (liver cirrhosis and liver cancer, etc.) and usage of artificial liver were analyzed. According to the 6-month follow-up results after discharge, the differences in the etiological indicators of died and survival patients and the outcome of patients with different types of liver failure were analyzed. RESULTS: A total of 369 patients were enrolled, including 134 (36.3%) with liver failure not caused by HBV and 235 (63.7%) with liver failure caused by HBV. The male with HBV-related liver failure was 4.34 times higher than female (cases: 191 vs. 44), which was higher than non-HBV-related liver failure (1.03 times, cases: 68 vs. 66). The 6-month follow-up showed that the proportion of male with HBV-related liver failure who died and survived was significantly higher than that of female (78.76% vs. 21.24% in died patients, 92.86% vs. 7.14% in survival patients, both P < 0.01). The age of died patients in the non-HBV-related liver failure group was significantly higher than that of the survival patients (years: 58.53±0.15 vs. 54.38±3.01, P < 0.05), and the AT III level was significantly lower than that of the survival patients [(32.20±6.43)% vs. (38.63±2.74)%, P < 0.05]. The length of ICU stay of the died HBV-related liver failure group was significantly shorter than that of the survival patients (days: 23.77±11.74 vs. 35.51±2.85, P < 0.01). The 6-month mortality after discharge of HBV-related liver failure combined with liver cancer was significantly higher than that of non-HBV-related liver failure (12.34% vs. 2.24%, P < 0.01), but there was no significant difference in 6-month mortality after discharge of patients receiving artificial liver and those with hepatic encephalopathy and cirrhosis between different types of liver failure groups. CONCLUSIONS: HBV is the main cause of liver failure. Patients with HBV-related liver failure were younger and had a longer hospitalization period, which was conducive to the recovery of the disease. HBV-related liver failure accompanied with liver cancer is the main factors of death. The AT III has the potential value to reflect the disease outcome.

Identification of a 5-Hydroxymethylation Signature in Circulating Cell-Free DNA for the Noninvasive Detection of Colorectal Cancer.

Background: As a crucial epigenetic modification, DNA 5-hydroxymethylcytosine (5-hmC) plays a key role during colorectal cancer (CRC) carcinogenesis. Nevertheless, the levels of 5-hmC-related genes in the circulating DNA of CRC remain largely unknown. Methods and Results: The GSE81314 dataset from the Gene Expression Omnibus (GEO), which was generated by chemical marking-based low-input shotgun sequencing to detect 5-hmC in circulating cell-free DNA (cfDNA) was used in the present study. The GSE81314 dataset includes data for 8 plasma samples from healthy individuals and 4 plasma samples from CRC patients. The difference in the 5-hmC levels in cfDNA between the CRC group and healthy individuals was analyzed by the differentially expressed genes (DEG) package. Weighted gene coexpression network analysis (WGCNA) was conducted to analyze gene coexpression modules associated with sample characteristics. DEG analysis identified 19 upregulated and 9 downregulated 5-hmC-related genes. WGCNA showed that the pink, purple, and brown modules, which contain 531 genes in total, were significantly correlated with CRC (0.66, 0.61, and -0.59, respectively). We used gene set enrichment analysis (GSEA) software to compare 5-hmC-related genes and pathways between CRC patients and healthy controls. We further performed a protein-protein interaction (PPI) analysis and identified 4 nodes (LCN2, LRG1, S100P, and TACSTD2) that played key roles in the network, and we analyzed the expression of these nodes S100P in the GEPIA database. Consistent with the 5-hmC levels in CRC patient plasma, our external validation results from the GEPIA and UALCAN databases showed that LCN2, LRG1, S100P, and TACSTD2 were highly expressed in CRC tissue compared with controls. The DNA promoter methylation levels of LCN2, LRG1, and S100P were lower in CRC tissue than in normal control tissue. Conclusion: The present findings suggest that abnormality in cell-free DNA hydroxylation in plasma may be associated with CRC. In addition, the 5-hmC levels of LCN2, LRG1, S100P, and TACSTD2 in circulating cfDNA may be used as potential noninvasive markers for CRC.

miR-138-5p Inhibits Vascular Mimicry by Targeting the HIF-1α/VEGFA Pathway in Hepatocellular Carcinoma.

Tumour vascular mimicry (VM) is the process by which new blood vessels are formed by tumour cells rather than endothelial cells. An increasing number of studies have revealed that the VM process is associated with cancer progression and metastasis. MiR-138-5p has been reported to act as a tumour suppressor in many cancers. However, the role and underlying mechanism of miR-138-5p in hepatocellular carcinoma (HCC) VM remain unclear. In this study, VM density was detected by CD31/periodic acid-Schiff double staining in HCC clinical specimens. We found that miR-138-5p expression correlated strongly and negatively with microvessel density. Additionally, the miR-138-5p mimic or inhibitor decreased or increased, respectively, tube formation capacity in HepG2 and Hep3B cells. Consistent with this finding, miR-138-5p repressed vessel density in vivo. Moreover, miR-138-5p targeted hypoxia-inducible factor 1α (HIF-1α) and regulated the expression of HIF-1α and vascular endothelial growth factor A (VEGFA), which are established classical master regulators for angiogenesis. Consistent with these findings, the HIF-1α inhibitor CAY10585 effectively blocked HCC cell VM and VEGFA expression. In conclusion, miR-138-5p inhibits HepG2 and Hep3B cell VM by blocking the HIF-1α/VEGFA pathway. Therefore, miR-138-5p may serve as a useful therapeutic target for miRNA-based HCC therapy.

Epidemiology, Environmental Risks, Virulence, and Resistance Determinants of Klebsiella pneumoniae From Dairy Cows in Hubei, China.

Klebsiella pneumoniae (K. pneumoniae) is an opportunistic pathogen, which causes serious infections in humans and animals. To investigate the antimicrobial resistance pattern and virulence profile of K. pneumoniae, a total of 887 samples were collected from both the healthy and mastitis cows and the bedding, feed, feces, air, drinking water, spraying water, washing water, and milk cup swabs from five dairy farms in Hubei, China, during 2019 and 2020. K. pneumoniae was isolated and identified using PCR of the khe and 16S rDNA sequencing. A genotypic characterization was performed for K. pneumoniae isolates using wzi typing and multilocus sequence typing (MLST). Antimicrobial resistances were confirmed using broth microdilution against 17 antimicrobial agents and resistance and virulence genes were determined by PCR. The prevalence of K. pneumoniae was 26.94% (239/887) distributed in 101 wzi allele types (199/239, 83.26%) and 100 sequence types (STs) (209/239, 87.45%), including 5 new wzi allele type and 25 new STs. Phylogenetic analysis showed that K. pneumoniae isolated from milk, nipple swab, feed, and feces is classified in the same clone complex. By comparing with the PubMLST database, at least 67 STs have the risk of spreading in different species and regions. Interestingly, 60 STs have been isolated from humans. The isolates were highly sensitive to meropenem and colistin, but resistant to ampicillin (100%), sulfisoxazole (94.56%), cephalothin (47.28%), streptomycin (30.13%), and so on. Noteworthy, multidrug-resistant (MDR) rate was found to be 43.93% in this study. By PCR, 30 of 68 antimicrobial resistance (AMR) genes were identified; the prevalence rate of blaTEM, blaSHV, strA, strB, aadA1, and aac(6')-Ib-cr was more than 50%. Eleven CTX-M-producing K. pneumoniae were found. The detection rate of fimH, mrkD, uge, wabG, entB, iutA, iroN, and ureA was over 85%. This study reinforces the epidemiological importance of K. pneumoniae in food-producing animals in Hubei. The emergence and spread of environmental MDR K. pneumoniae may pose a potential threat to food safety and public health.

[The predictive value of liver failure-related etiology for clinical outcomes].

OBJECTIVE: To assess the predictors of outcomes for different subtypes of liver failure, and the effectiveness of artificial liver support systems in the treatment of liver failure. METHODS: The clinical data of 112 patients with hepatitis B virus (HBV)- and non-HBV-related liver failure admitted to the intensive care unit (ICU) of the Fifth People's Hospital of Wuxi were collected from January to December 2020. The relevant etiologies of acute, subacute, acute-on-chronic, subacute-on-chronic, chronic subtype liver failure were analyzed. The efficacies of artificial liver support systems in the treatment of various subtypes of liver failure were also compared. The correlation of various indicators was analyzed by Spearman correlation analysis, the risk factors affecting the prognosis of patients with liver failure were analyzed by multivariate Logistic regression equation, and receiver operator characteristic curve (ROC curve) of subjects was plotted to evaluate the predictive value of each risk factor for the prognosis of patients with liver failure. RESULTS: Among the 112 liver failure patients, 63 were caused by hepatitis B and 49 were caused by non-hepatitis B. The liver failure caused by hepatitis B was 6 times higher than for men than for women, which was higher than that of non-HBV liver failure group (1.33 times). Antithrombin III (AT III) and total bilirubin (TBil) levels of subacute liver failure were higher than those of pre-liver failure in the HBV liver failure group [AT III: (59.33±14.57)% vs. (35.66±20.72)%, TBil (µmol/L): 399.21±112.94 vs. 206.08±126.96, both P < 0.05]. The levels of AT III in patients with pre-liver failure and chronic liver failure in the non-HBV liver failure group were significantly higher than those with acute liver failure [(58.33±15.28)%, (44.00±19.10)% vs. (31.33±7.57)%, both P < 0.05], patients with acute liver failure had significantly lower level of TBil than pre-liver failure (µmol/L: 107.83±49.73 vs. 286.20±128.92, P < 0.05), the TBil levels in patients with subacute and acute-on-chronic liver failure were also significantly higher than that in pre-liver failure group (µmol/L: 417.27±118.60, 373.00±187.00 vs. 286.20±128.92, both P < 0.05). Patients with subacute liver failure, subacute-on-chronic liver failure and chronic liver failure in the non-HBV failure group were significantly longer than those in acute liver failure (days: 36.00±8.31, 27.52±11.71, 27.72±22.71 vs. 11.00±1.41, all P < 0.05). There was no statistically significant difference in the case fatality rate of using the artificial liver support system between the HBV failure group and the non-HBV failure group (55.6% vs. 50.0%, P < 0.05), the levels of AT III in the two groups of surviving patients were significantly higher than that of the dead [HBV liver failure group: (36.20±6.26)% vs. (27.33±8.87)%, non-HBV liver failure group: (41.06±4.16)% vs. (28.71±12.35)%, both P < 0.01]. Correlation analysis showed that there was a clear positive correlation between AT III and TBil in the dead patients of HBV liver failure group and the survival and death patients of non-HBV liver failure group (r values were 0.069, 0.341, 0.064, and P values were 0.723, 1.196 and 0.761, respectively); there was a significant inverse correlation between AT III and TBil in the HBV liver failure group (r = -0.105, P = 0.745). Multivariate Logistic regression analysis showed that AT III was an independent risk factor affecting the prognosis of patients with non-HBV liver failure [odd ratio (OR) = 1.023, 95% confidence interval (95%CI) was -0.001 to 0.001, P = 0.007]. TBil was an independent risk factor affecting prognosis of patients with HBV liver failure (OR = 1.005, 95%CI was -0.002 to -7.543, P = 0.033). The analysis of ROC curve showed that AT III had a predictive value for the prognosis of patients with non-HBV liver failure, the area under the ROC curve (AUC) = 0.747, the 95%CI was 0.592-0.902, P = 0.009. When the optimal truncation value was 39.5%, its sensitivity and specificity were 83.33% and 56.25%, respectively. CONCLUSIONS: Artificial liver support system treatment of liver failure was difficult to effectively reduce the mortality of patients with end-stage liver failure. In addition to AT III, TBil also could be used as an indicator to assess liver compensatency and predict prognosis in liver failure patients.

The impacts of COVID-19 pandemic on China's transport sectors based on the CGE model coupled with a decomposition analysis approach.

As one of the most vulnerable sectors exposed to the COVID-19 pandemic, transport sectors have been severely affected. However, the shocks and impact mechanisms of infectious diseases on transport sectors are not fully understood. This paper employs a multi-sectoral computable general equilibrium model of China, CHINAGEM, with highly disaggregated transport sectors to examine the impacts of the COVID-19 pandemic on China's transport sectors and reveal the impact mechanisms of the pandemic shocks with the decomposition analysis approach. This study suggests that, first, multiple shocks of the COVID-19 pandemic to transport sectors are specified, including the supply-side shocks that raised the protective cost and reduced the production efficiency of transport sectors, and the demand-side shocks that reduced the demand of households and production sectors for transportation. Second, the outputs of all transport sectors in China have been severely affected by the COVID-19 pandemic, and passenger transport sectors have larger output decreases than freight transport sectors. While the outputs of freight transport sectors are expected to decline by 1.03-2.85%, the outputs of passenger transport sectors would decline by 3.08-11.44%. Third, with the decomposition analysis, the impacts of various exogenous shocks are quite different, while the changes in the output of different transport sectors are dominated by different exogenous shocks. Lastly, while the supply-side shocks of the pandemic would drive output decline in railway, waterway, and aviation transport sectors, the demand-side shocks would drive so in the road, pipeline, and other transport sectors. Moreover, the COVID-19 pandemic has negative impacts on the output of most non-transport sectors and the macro-economy in China. Three policy implications are recommended to mitigate the damages caused by the COVID-19 pandemic to the transport sectors.

Structure, preparation, modification, and bioactivities of ß-glucan and mannan from yeast cell wall: A review.

In order to solve the antibiotic resistance, the research on antibiotic substitutes has received an extensive attention. Many studies have shown that ß-glucan and mannan from yeast cell wall have the potential to replace antibiotics for the prevention and treatment of animal diseases, thereby reducing the development and spread of antibiotic-resistant bacterial pathogens. ß-Glucan and mannan had a variety of biological functions, including improving the intestinal environment, stimulating innate and acquired immunity, adsorbing mycotoxins, enhancing antioxidant capacity, and so on. The biological activities of ß-glucan and mannan can be improved by chemically modifying its primary structure or reducing molecular weight. In this paper, the structure, preparation, modification, and biological activities of ß-glucan and mannan were reviewed, which provided future perspectives of ß-glucan and mannan.

Countermeasures against economic crisis from COVID-19 pandemic in China: An analysis of effectiveness and trade-offs.

The effectiveness of different countermeasures to economic crisis from the public health emergency is still inadequately understood. We establish an illustrative scenario, specifying the shocks of COVID-19 pandemic and countermeasures applying a general equilibrium model to analyze the effectiveness of countermeasures with a particular focus on trade-offs in the impacts of monetary and fiscal policies. We find that both monetary and fiscal countermeasures could effectively mitigate the economic damages to GDP and employment. However, they would also produce adverse side-effects such as an increase in consumer price by 1.05% and 0.57%, respectively, and a decline in exports by 2.61% and 1.05%, respectively. Monetary policies would exacerbate the damages to external demand by supply-side shocks of the pandemic, but they are more suitable for mitigating demand-side shocks. While fiscal policies would benefit nearly all producing sectors, monetary policies would mainly affect export-oriented manufacturing sectors negatively.

Establishment and Clinical Application of a Method for Detecting T Lymphocyte Subsets by Cellular Immunochip Technology.

OBJECTIVE: To establish and verify the method for detecting the immune phenotype of peripheral blood T lymphocytes by cellular immune chip technology, analyze the immune status, and discuss its clinical diagnostic value of different populations in the Qingyuan area. METHODS: First, a cellular immune chip was used to detect the number of T lymphocyte subsets CD3+, CD4+, CD8+, and CD4/CD8, followed by evaluating the accuracy and precision through a comparison with flow cytometry. After passing the performance verification, a large-scale detection was performed by a cellular immune chip in 8389 cases. Immunochip technology detects the expression of T lymphocyte subsets and analyzes the differences in cellular immune function among people with physical examination, inflammation, and cancer, as well as different cancer types and in genders. RESULTS: The cell immunochip method and flow cytometry method have the same accuracy and precision in detecting specimens, and the former is fast and simple, and is suitable for clinical use; big data analysis is expected to establish a reference range for CD3+, CD4+, and CD8+ T cell counts in Qingyuan. There are statistical differences in CD3+, CD4+, CD8+ T cell counts in physical examination, inflammation and cancer populations; there are also certain differences in CD3+, CD4+, CD8+ T cell counts and CD4/CD8 ratios between different cancer types and different diseases. CONCLUSION: The method of cell immunochip technology to detect T lymphocyte subsets is simple and practical, with accurate results and rapid detection. It can be used for immune function monitoring and treatment prognosis evaluation of people with different diseases, and it is worthy of popularization and application in clinical practice.

Progress on the Antimicrobial Activity Research of Clove Oil and Eugenol in the Food Antisepsis Field.

As potential and valuable antiseptics in the food industry, clove oil and its main effective composition eugenol show beneficial advantages on antibacterial and antifungal activity, aromaticity, and safety. Researches find that both clove oil and eugenol express significantly inhibitory effects on numerous kinds of food source microorganisms, and the mechanisms are associated with reducing the migratory and adhesion and inhibiting the synthesis of biofilm and various virulence factors of these microorganisms. Clove oil and eugenol are generally regarded as safe in vivo experiments. However, they may express certain cytotoxicity on fibroblasts and other cells in vitro. Studies on the quality and additive standard of clove oil and eugenol should be strengthened to promote the antiseptic effects of them in the food antiseptic field.

Ultrasonically synthesized organic liquid-filled chitosan microcapsules: part 2: characterization using AFM (atomic force microscopy) and combined AFM-confocal laser scanning fluorescence microscopy.

Atomic Force Microscopy (AFM) is used to measure the stiffness and Young's modulus of individual microcapsules that have a chitosan cross-linked shell encapsulating tetradecane. The oil filled microcapsules were prepared using a one pot synthesis via ultrasonic emulsification of tetradecane and crosslinking of the chitosan shell in aqueous solutions of acetic acid. The concentration of acetic acid in aqueous solutions of chitosan was varied from 0.2% to 25% v/v. The effect of acetic acid concentration and size of the individual microcapsules on the strength was probed. The deformations and forces required to rupture the microcapsules were also measured. Three dimensional deformations of microcapsules under large applied loads were obtained by the combination of Laser Scanning Confocal Microscopy (LSCM) with Atomic Force Microscopy (AFM). The stiffness, and hence the modulus, of the microcapsules was found to decrease with an increase in size with the average stiffness ranging from 82 to 111 mN m-1 and average Young's modulus ranging from 0.4 to 6.5 MPa. The forces required to rupture the microcapsules varied from 150 to 250 nN with deformations of the microcapsules up to 62 to 110% relative to their radius, respectively. Three dimensional images obtained using laser scanning confocal microscopy showed that the microcapsules retained their structure and shape after being subjected to large deformations and subsequent removal of the loads. Based on the above observations, the oil filled chitosan crosslinked microcapsules are an ideal choice for use in the food and pharmaceutical industries as they would be able to withstand the process conditions encountered.

Ultrasonically synthesized organic liquid-filled chitosan microcapsules: part 1: tuning physical & functional properties.

This study reports the synthesis of tetradecane-filled chitosan microcapsules in acetic acid aqueous solutions using high intensity ultrasound at 20 kHz. The size, size distribution, and stability of microcapsules were tuned by varying the concentration of acetic acid from 0.2% to 25% v/v. After long-time storage at room temperature (more than 3 months), the microcapsules maintained their shell-core structure where the volume of the microcapsules at 0.2% acetic acid concentration increased by 8.3% due to leaking and coalescence. Microcapsules were consistently spherical and had a smooth shell surface, however, their shell thickness varied with acetic acid concentration. The relaxation behavior of individual microcapsules to an applied constant stress was measured by atomic force microscopy (AFM) to probe the shell strength and extent of crosslinking. The effect of acetic acid on the relative viscosity of chitosan aqueous solutions played a major role in microcapsule size control at low acid concentrations. With constant addition of acetic acid, amino groups in chitosan chains were acetylated partially under ultrasonic irradiation. This reduced the amphiphilicity of the shell material and therefore influenced the size, size distribution, stability and mechanical strength of the microcapsules. Apart from the acetylation effect, the counter-ion effect and the formation of covalent bond crosslinks also made contributions to the formation of stable chitosan microcapsules.

Identification of a novel torque teno mini virus in cerebrospinal fluid from a child with encephalitis.

Anelloviruses are single-strand circular DNA viruses and ubiquitous within the human population. Although there is no direct evidence, many studies have suggested the anelloviruses may be associated with a variety of diseases. In this study, a novel torque teno mini virus (TTMV) was detected in a child with unexplained encephalitis. The detected virus had a circular genome of 2943 nt in length and 3 open reading frames. It shared 45.4% - 35.9% nucleotide identities with known TTMV species and < 35% with the other species of anellovirus, which suggested it might belong to a new species within the genus Betatorquevirus. Phylogenetic analysis based on the amino acid sequences of ORF1 showed that this virus represented a distinct branch within the diversity of anellovirus. Whether this novel anellovirus strain is associated with encephalitis requires further study.

Sonochemical and sustainable synthesis of graphene-gold (G-Au) nanocomposites for enzymeless and selective electrochemical detection of nitric oxide.

In this study, a sonochemical approach was utilised for the development of graphene-gold (G-Au) nanocomposite. Through the sonochemical method, simultaneous exfoliation of graphite and the reduction of gold chloride occurs to produce highly crystalline G-Au nanocomposite. The in situ growth of gold nanoparticles (AuNPs) took place on the surface of exfoliated few-layer graphene sheets. The G-Au nanocomposite was characterised by UV-vis, XRD, FTIR, TEM, XPS and Raman spectroscopy techniques. This G-Au nanocomposite was used to modify glassy carbon electrode (GCE) to fabricate an electrochemical sensor for the selective detection of nitric oxide (NO), a critical cancer biomarker. G-Au modified GCE exhibited an enhanced electrocatalytic response towards the oxidation of NO as compared to other control electrodes. The electrochemical detection of NO was investigated by linear sweep voltammetry analysis, utilising the G-Au modified GCE in a linear range of 10-5000µM which exhibited a limit of detection of 0.04µM (S/N=3). Furthermore, this enzyme-free G-Au/GCE exhibited an excellent selectivity towards NO in the presence of interferences. The synergistic effect of graphene and AuNPs, which facilitated exceptional electron-transfer processes between the electrolyte and the GCE thereby improving the sensing performance of the fabricated G-Au modified electrode with stable and reproducible responses. This G-Au nanocomposite introduces a new electrode material in the sensitive and selective detection of NO, a prominent biomarker of cancer.

Ultrasonic synthesis of stable oil filled microcapsules using thiolated chitosan and their characterization by AFM and numerical simulations.

An experimental protocol has been developed for synthesizing stable core-shell microcapsules using a biopolymer, chitosan, lacking cross-linkable thiol functional groups. In the first step, thiol moieties were introduced into the backbone of chitosan using dl-N-acetylhomocysteine thiolactone (AHT). In the second step, AHT-modified chitosan shelled microcapsules, encapsulating an oil core, were successfully prepared using high intensity 20 kHz ultrasound. The size of chitosan and AHT modified chitosan microcapsules was found to be in the range of 1-15 µm. The thickness of the microcapsule shell increased with an increase in thiol content. The mechanical properties of microcapsules were evaluated by subjecting the microcapsules to compressive forces by colloidal probe AFM. The stiffness and the Young's modulus of the shell of microcapsules were determined by analyzing the force versus indentation data using Reissner's theory for indentation of thin elastic shells. The stiffness of AHT modified chitosan microcapsules was found to be higher than unmodified chitosan microcapsules. The viability of microcapsules to be embedded into processed food, pharmaceutical and cosmetic products was tested via numerical simulations. The confined capsule in the micro-channel was subjected to linear shear and uniform flows. We used finite element numerical simulations to determine the deformation of microcapsules in flow as a function of shear rate and thickness of the shell. The deformation of capsule was found to be linear with an increase in the shear rate. The deformation decreased with an increase in the thickness of the shell. Based on the simulations, we predict that the microcapsules would survive processing conditions and shear rates used in industrial applications.