Fabrication and characterization of antibacterial nanofiber membranes modified with chitosan and imidazolidinyl urea for potential use in biological waste treatments.

An ion exchange nanofiber membrane (AEA-COOH) was developed from polyacrylonitrile (PAN) nanofibers through chemical hydrolysis. It was further modified by grafting chitosan (CS) onto its surface, creating the AEA-COOH-CS membrane. Then, both membranes were covalently immobilized with imidazolidinyl urea (IU), resulting in AEA-COOH-IU and AEA-COOH-CS-IU membranes. This study analyzed their physical properties, antibacterial efficacy (AE), and reusability. Optimal conditions were identified: 50 kDa molecular weight of chitosan, pH 8 for IU modification, and 0.05 % IU concentration. The AEA-COOH-IU membrane achieved 96.15 % AE against Escherichia coli at an initial concentration of 2.0 × 107 CFU/mL, while the AEA-COOH-CS-IU membrane achieved 100 % AE. The AEA-COOH-CS-IU membrane maintained 95.04 % efficacy over 5 cycles, demonstrating superior durability. As a result, the AEA-COOH-CS-IU membrane has high potential for environmental applications such as water purification and wastewater treatment. Its robust antibacterial properties and reusability suggest a significant impact on ensuring cleaner water resources and prospective uses in the biomedical field, including medical device coatings and healthcare applications.

Alginate and chitosan-based polyamide 56 modified nanofiber membrane for highly effective capture of Escherichia coli: Antibacterial and cytotoxicity studies.

In recent years, microbial fermentation has become a sustainable alternative to traditional petrochemical processes for producing biomass nylon 56 (i.e., PA56). This study is centered on creating a highly efficient antibacterial nanofiber membrane using bio-nylon 56 as the main material. The membrane was fabricated via a multi-step process involving sodium alginate, chitosan, and poly(hexamethylene biguanide) (PHMB). The PA56 nanofiber was chemically modified by sequential coupling with alginate (AG) and chitosan (CS), introducing a significant number of functional groups (-COOH and -NH2). This process resulted in the formation of PA56-AG and PA56-AG-CS nanofibers. Further modification with PHMB led to obtaining the PA56-AG-PHMB and PA56-AG-CS-PHMB antibacterial nanofiber membranes. The optimal preparation conditions for these membranes were determined, including the pH and concentration of AG, the molecular weight, pH, and concentration of CS, and the pH and concentration of PHMB. The PA56-based membranes demonstrated nearly 100 % antibacterial efficiency within a short time. However, the PA56-AG-PHMB membrane exhibited faster antibacterial rates and higher efficiency in repeated use compared to the PA56-AG-CS-PHMB membrane. The two-step coupling reaction in the preparation of PA56-AG-CS-PHMB may have reduced its surface accessibility to E. coli cells, resulting in slower bacterial attachment. Furthermore, the PA56-related membranes showed excellent biocompatibility, with a 100 % cell survival rate. Despite some limitations in reusability, biomass nylon PA56 stands out as an environmentally friendly material derived from renewable resources through microbial fermentation. It offers significant sustainability advantages over traditional petroleum-based nylons, as evidenced by the favorable cytotoxicity test results.

Detection of maternal carriers of common α-thalassemia deletions from cell-free DNA.

α-Thalassemia is a common inherited blood disorder manifested mainly by the deletions of α-globin genes. In geographical areas with high carrier frequencies, screening of α-thalassemia carrier state is therefore of vital importance. This study presents a novel method for identifying female carriers of common α-thalassemia deletions using samples routinely taken for non-invasive prenatal tests for screening of fetal chromosomal aneuploidies. A total of 68,885 Vietnamese pregnant women were recruited and α-thalassemia statuses were determined by gap-PCR, revealing 5344 women (7.76%) carried deletions including αα/--SEA (4.066%), αα/-α3.7 (2.934%), αα/-α4.2 (0.656%), and rare genotypes (0.102%). A two-stage model was built to predict these α-thalassemia deletions from targeted sequencing of the HBA gene cluster on maternal cfDNA. Our method achieved F1-scores of 97.14-99.55% for detecting the three common genotypes and 94.74% for detecting rare genotypes (-α3.7/-α4.2, αα/--THAI, -α3.7/--SEA, -α4.2/--SEA). Additionally, the positive predictive values were 100.00% for αα/αα, 99.29% for αα/--SEA, 94.87% for αα/-α3.7, and 96.51% for αα/-α4.2; and the negative predictive values were 97.63%, 99.99%, 99.99%, and 100.00%, respectively. As NIPT is increasingly adopted for pregnant women, utilizing cfDNA from NIPT to detect maternal carriers of common α-thalassemia deletions will be cost-effective and expand the benefits of NIPT.

Influenza A Viruses of Swine (IAV-S) in Vietnam from 2010 to 2015: Multiple Introductions of A(H1N1)pdm09 Viruses into the Pig Population and Diversifying Genetic Constellations of Enzootic IAV-S.

Active surveillance of influenza A viruses of swine (IAV-S) involving 262 farms and 10 slaughterhouses in seven provinces in northern and southern Vietnam from 2010 to 2015 yielded 388 isolates from 32 farms; these viruses were classified into H1N1, H1N2, and H3N2 subtypes. Whole-genome sequencing followed by phylogenetic analysis revealed that the isolates represented 15 genotypes, according to the genetic constellation of the eight segments. All of the H1N1 viruses were entirely A(H1N1)pdm09 viruses, whereas all of the H1N2 and H3N2 viruses were reassortants among 5 distinct ancestral viruses: H1 and H3 triple-reassortant (TR) IAV-S that originated from North American pre-2009 human seasonal H1, human seasonal H3N2, and A(H1N1)pdm09 viruses. Notably, 93% of the reassortant IAV-S retained M genes that were derived from A(H1N1)pdm09, suggesting some advantage in terms of their host adaptation. Bayesian Markov chain Monte Carlo analysis revealed that multiple introductions of A(H1N1)pdm09 and TR IAV-S into the Vietnamese pig population have driven the genetic diversity of currently circulating Vietnamese IAV-S. In addition, our results indicate that a reassortant IAV-S with human-like H3 and N2 genes and an A(H1N1)pdm09 origin M gene likely caused a human case in Ho Chi Minh City in 2010. Our current findings indicate that human-to-pig transmission as well as cocirculation of different IAV-S have contributed to diversifying the gene constellations of IAV-S in Vietnam. IMPORTANCE: This comprehensive genetic characterization of 388 influenza A viruses of swine (IAV-S) isolated through active surveillance of Vietnamese pig farms from 2010 through 2015 provides molecular epidemiological insight into the genetic diversification of IAV-S in Vietnam after the emergence of A(H1N1)pdm09 viruses. Multiple reassortments among A(H1N1)pdm09 viruses and enzootic IAV-S yielded 14 genotypes, 9 of which carried novel gene combinations. The reassortants that carried M genes derived from A(H1N1)pdm09 viruses became predominant, replacing those of the IAV-S that had been endemic in Vietnam since 2011. Notably, one of the novel reassortants likely caused a human case in Vietnam. Given that Vietnam is the second-largest pig-producing country in Asia, continued monitoring of IAV-S is highly important from the viewpoints of both the swine industry and human public health.