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Photoelectrocatalytic mechanism of PEDOT modified filtration membrane

Shi L, Liu J, Gao B, Sillanpää M

Sci Total Environ, 2022 Mar 20;813:152397.
PMID: 34923007 DOI: 10.1016/j.scitotenv.2021.152397

The generation of free radicals is the key to the photocatalytic efficiency. In this study, the degradation mechanism of photoelectrocatalysis (PEC) membrane could be adequately explained by exploring the generation pathway of different free radicals. The PEC membrane was prepared by gas phase polymerization of poly (3, 4-ethylene dioxythiophene) (PEDOT) on non-woven fabric, industrial filter cloth, ceramic membrane and polyvinylidene fluoride (PVDF) membrane, respectively. Three-dimensional fluorescence test showed that the optimal degradation of mixed or monomer contamination (bovine serum protein, sodium humate, and sodium alginate) was achieved by modified ceramic membrane under PEC condition. As for self-cleaning experiment, the membrane resistance decreased 65.7% when the reaction conditions changed from dark to PEC for 30 min. Combined with the characterization results, PEDOT as photocapacitance extended electron lifetime and promoted free radical generation. This system was mainly dependent on superoxide free radicals (0.01 mmol/L) and singlet oxygen (0.10 mmol/L), which came from energy and electron transfer. Oxygen vacancy could adsorb oxygen to produce superoxide radicals, which was further oxidized to singlet oxygen. In addition, the π-electron conjugated system of PEDOT accelerated the hole transfer and the separation of electrons and holes. Also, this study provided a new view of reactive oxygen species generation mechanism from PEDOT modified membrane.
The activation of peroxymonosulfate by biochar derived from anaerobic and aerobic iron-containing excess sludge

Duan Y, Gao B, Liu J, Sillanpää M

Environ Sci Pollut Res Int, 2023 Mar 31.
PMID: 37000396 DOI: 10.1007/s11356-023-26622-0

The excess sludge from municipal sewage treatment plants is rich in Fe (III) due to chemical dephosphorization. The activation of peroxymonosulfate (PMS) by biochar derived from anaerobic and aerobic iron-containing excess sludge was studied systematically in this research. Fe (III)-containing excess sludge was cultured in an anaerobic environment for conversion of partial Fe (III) to Fe (II), which was further carbonized to prepare biochar labeled AnSx@Fe. Meanwhile, aerobic sludge with different Fe (III) content was directly carbonized to produce biochar labeled AeS@Fe. For biochar (AnS20@Fe-15%) prepared from 15% Fe(III)-containing anaerobic cultured 20 days sludge, the relative contents of Fe (III) and Fe (II) were 21.26% and 78.74%, which were 31.03% and 68.97% for biochar (AeS@Fe-10%) prepared from 10% Fe (III)-containing aerobic sludge. Fe (III) can be reduced to Fe (II) by both anaerobic culture and carbonization. Their removal rates of tetracycline (TC) through 60 min PMS activation were 97% and 98%, with TOC (Total organic carbon) removal of 61.8% and 53.4% respectively. The reactive species including sulfate radical [Formula: see text], hydroxyl radical (·OH) and singlet oxygen (1O2) were produced during PMS activation. After O2-aeration treatment of both AeS@Fe and AnSx@Fe, the relative content of Fe (II) was decreased and group C = O was disappeared, which resulted in reduction of [Formula: see text], ·OH and 1O2. The generation of [Formula: see text] and ·OH was dominated by the Fe (II) activation and the 1O2 generation was originated from graphite type N and C = O. Direct carbonization of aerobic and anaerobic sludge is a feasible method to produce biochar for PMS activation.
Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications

Gao B, Wang L, Han S, Pingguan-Murphy B, Zhang X, Xu F

Crit Rev Biotechnol, 2016 Aug;36(4):619-29.
PMID: 25669871 DOI: 10.3109/07388551.2014.1002381

Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.
Hydrogel-based methods for engineering cellular microenvironment with spatiotemporal gradients

Wang L, Li Y, Huang G, Zhang X, Pingguan-Murphy B, Gao B, et al.

Crit Rev Biotechnol, 2016 Jun;36(3):553-65.
PMID: 25641330 DOI: 10.3109/07388551.2014.993588

Natural cellular microenvironment consists of spatiotemporal gradients of multiple physical (e.g. extracellular matrix stiffness, porosity and stress/strain) and chemical cues (e.g. morphogens), which play important roles in regulating cell behaviors including spreading, proliferation, migration, differentiation and apoptosis, especially for pathological processes such as tumor formation and progression. Therefore, it is essential to engineer cellular gradient microenvironment incorporating various gradients for the fabrication of normal and pathological tissue models in vitro. In this article, we firstly review the development of engineering cellular physical and chemical gradients with cytocompatible hydrogels in both two-dimension and three-dimension formats. We then present current advances in the application of engineered gradient microenvironments for the fabrication of disease models in vitro. Finally, concluding remarks and future perspectives for engineering cellular gradients are given.
Fulltext Functional expression of a novel α-amylase from Antarctic psychrotolerant fungus for baking industry and its magnetic immobilization

He L, Mao Y, Zhang L, Wang H, Alias SA, Gao B, et al.

BMC Biotechnol, 2017 02 28;17(1):22.
PMID: 28245836 DOI: 10.1186/s12896-017-0343-8

BACKGROUND: α-Amylase plays a pivotal role in a broad range of industrial processes. To meet increasing demands of biocatalytic tasks, considerable efforts have been made to isolate enzymes produced by extremophiles. However, the relevant data of α-amylases from cold-adapted fungi are still insufficient. In addition, bread quality presents a particular interest due to its high consummation. Thus developing amylases to improve textural properties could combine health benefits with good sensory properties. Furthermore, iron oxide nanoparticles provide an economical and convenient method for separation of biomacromolecules. In order to maximize the catalytic efficiency of α-amylase and support further applications, a comprehensive characterization of magnetic immobilization of α-amylase is crucial and needed.
RESULTS: A novel α-amylase (AmyA1) containing an open reading frame of 1482 bp was cloned from Antarctic psychrotolerant fungus G. pannorum and then expressed in the newly constructed Aspergillus oryzae system. The purified recombinant AmyA1 was approximate 52 kDa. AmyA1 was optimally active at pH 5.0 and 40 °C, and retained over 20% of maximal activity at 0-20 °C. The K m and V max values toward soluble starch were 2.51 mg/mL and 8.24 × 10-2 mg/(mL min) respectively, with specific activity of 12.8 × 103 U/mg. AmyA1 presented broad substrate specificity, and the main hydrolysis products were glucose, maltose, and maltotetraose. The influence of AmyA1 on the quality of bread was further investigated. The application study shows a 26% increase in specific volume, 14.5% increase in cohesiveness and 14.1% decrease in gumminess in comparison with the control. AmyA1 was immobilized on magnetic nanoparticles and characterized. The immobilized enzyme showed improved thermostability and enhanced pH tolerance under neutral conditions. Also, magnetically immobilized AmyA1 can be easily recovered and reused for maximum utilization.
CONCLUSIONS: A novel α-amylase (AmyA1) from Antarctic psychrotolerant fungus was cloned, heterologous expression in Aspergillus oryzae, and characterized. The detailed report of the enzymatic properties of AmyA1 gives new insights into fungal cold-adapted amylase. Application study showed potential value of AmyA1 in the food and starch fields. In addition, AmyA1 was immobilized on magnetic nanoparticles and characterized. The improved stability and longer service life of AmyA1 could potentially benefit industrial applications.
Engineering ellipsoidal cap-like hydrogel particles as building blocks or sacrificial templates for three-dimensional cell culture

Zhang W, Huang G, Ng K, Ji Y, Gao B, Huang L, et al.

Biomater Sci, 2018 Mar 07.
PMID: 29511758 DOI: 10.1039/c7bm01186e

Hydrogel particles that can be engineered to compartmentally culture cells in a three-dimensional (3D) and high-throughput manner have attracted increasing interest in the biomedical area. However, the ability to generate hydrogel particles with specially designed structures and their potential biomedical applications need to be further explored. This work introduces a method for fabricating hydrogel particles in an ellipsoidal cap-like shape (i.e., ellipsoidal cap-like hydrogel particles) by employing an open-pore anodic aluminum oxide membrane. Hydrogel particles of different sizes are fabricated. The ability to produce ellipsoidal cap-like magnetic hydrogel particles with controlled distribution of magnetic nanoparticles is demonstrated. Encapsulated cells show high viability, indicating the potential for using these hydrogel particles as structure- and remote-controllable building blocks for tissue engineering application. Moreover, the hydrogel particles are also used as sacrificial templates for fabricating ellipsoidal cap-like concave wells, which are further applied for producing size controllable cell aggregates. The results are beneficial for the development of hydrogel particles and their applications in 3D cell culture.
Practice of dialysis access interventional nephrology procedures in the Asia-Pacific region: Getting lay of the land

Jasuja S, Gallieni M, Jha V, Vachharajani T, Bhalla AK, Tan J, et al.

Nephrology (Carlton), 2023 Dec;28(12):672-681.
PMID: 37697492 DOI: 10.1111/nep.14236

AIM: This cross-sectional survey aimed to determine the prevalence of Interventional Nephrology (IN) practice amongst nephrologists in the Asia-Pacific Region (APR), specifically related to dialysis access (DA).
METHODS: The Association of VA and intervenTionAl Renal physicians (AVATAR) Foundation from India conducted a multinational online survey amongst nephrologists from the Asia-Pacific to determine the practice of IN in the planning, creation, and management of dialysis access. The treatment modalities, manpower and equipment availability, monthly cost of treatment, specifics of dialysis access interventions, and challenges in the training and practice of IN by nephrologists were included in the survey.
RESULTS: Twenty-one countries from the APR participated in the survey. Nephrologists from 18 (85.7%) countries reported performing at least one of the basic dialysis access-related IN procedures, primarily the placement of non-tunnelled central catheters (n-TCC; 71.5%). Only 10 countries (47.6%) reported having an average of <4% of nephrologists performing any of the advanced IN access procedures, the most common being the placement of a peritoneal dialysis (PD) catheter (20%). Lack of formal training (57.14%), time (42.8%), incentive (38%), institutional support (38%), medico-legal protection (28.6%), and prohibitive cost (23.8%) were the main challenges to practice IN. The primary obstacles to implementing the IN training were a lack of funding and skilled personnel.
CONCLUSION: The practice of dialysis access-related IN in APR is inadequate, mostly due to a lack of training, backup support, and economic constraints, whereas training in access-related IN is constrained by a lack of a skilled workforce and finances.
Cross-Cancer Genome-Wide Association Study of Endometrial Cancer and Epithelial Ovarian Cancer Identifies Genetic Risk Regions Associated with Risk of Both Cancers

Glubb DM, Thompson DJ, Aben KKH, Alsulimani A, Amant F, Annibali D, et al.

Cancer Epidemiol Biomarkers Prev, 2021 Jan;30(1):217-228.
PMID: 33144283 DOI: 10.1158/1055-9965.EPI-20-0739

BACKGROUND: Accumulating evidence suggests a relationship between endometrial cancer and ovarian cancer. Independent genome-wide association studies (GWAS) for endometrial cancer and ovarian cancer have identified 16 and 27 risk regions, respectively, four of which overlap between the two cancers. We aimed to identify joint endometrial and ovarian cancer risk loci by performing a meta-analysis of GWAS summary statistics from these two cancers.
METHODS: Using LDScore regression, we explored the genetic correlation between endometrial cancer and ovarian cancer. To identify loci associated with the risk of both cancers, we implemented a pipeline of statistical genetic analyses (i.e., inverse-variance meta-analysis, colocalization, and M-values) and performed analyses stratified by subtype. Candidate target genes were then prioritized using functional genomic data.
RESULTS: Genetic correlation analysis revealed significant genetic correlation between the two cancers (rG = 0.43, P = 2.66 × 10-5). We found seven loci associated with risk for both cancers (P Bonferroni < 2.4 × 10-9). In addition, four novel subgenome-wide regions at 7p22.2, 7q22.1, 9p12, and 11q13.3 were identified (P < 5 × 10-7). Promoter-associated HiChIP chromatin loops from immortalized endometrium and ovarian cell lines and expression quantitative trait loci data highlighted candidate target genes for further investigation.
CONCLUSIONS: Using cross-cancer GWAS meta-analysis, we have identified several joint endometrial and ovarian cancer risk loci and candidate target genes for future functional analysis.
IMPACT: Our research highlights the shared genetic relationship between endometrial cancer and ovarian cancer. Further studies in larger sample sets are required to confirm our findings.