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• A cost-effective and eco-friendly polyDOPA@paper was prepared for DNA extraction. • The adsorption capacity of polyDOPA@paper for DNA was 20.7 μg cm−2. • An automated extraction system was designed to ensure results consistency. • The DNA extraction platform averts the need for specialized training of operators. • The platform combined with qPCR realized the detection of E. coli in milk samples. The success of polymerase chain reaction (PCR) depends on the quality of deoxyribonucleic acid (DNA) templates. This study developed a cost-effective and eco-friendly DNA extraction system utilizing poly(3,4-dihydroxyphenylalanine)-modified cellulose paper (polyDOPA@paper). PolyDOPA@paper was prepared by oxidatively self-polymerizing DOPA under weak alkaline conditions and utilizing the adhesive property of polyDOPA on different materials. Compared to the uncoated cellulose paper, polyDOPA coating significantly enhances DNA adsorption owing to its abundant amino, carboxyl, and hydroxyl moieties. The DNA extraction mechanism using polyDOPA@paper was discussed. The maximum adsorption capacity of polyDOPA@paper for DNA was 20.7 μg cm−2. Moreover, an automated extraction system was designed and fabricated using 3D printing technology. The device simplifies the operation and ensures the reproducibility and consistency of the results. More importantly, it eliminates the need for specialized training of operators. The feasibility of the polyDOPA@paper-based automated extraction system was evaluated by quantitatively detecting Escherichia coli in spiked milk samples via a real-time PCR. The detection limit was 102 cfu mL−1. The results suggest that the system would have significant potential in detecting pathogens. [ABSTRACT FROM AUTHOR]

The study investigates four paper-based materials designed for short-time wrapping of meat products by determining morpho-structure, capillary-hydroscopic, barrier and antibacterial properties, wettability and migration into food simulants. The paper-based materials are coded as RO, SP, IT and SLO. RO and SLO samples exhibit the best barrier properties against water vapors. The low solubility and contact angles of RO, IT and SLO in A simulant (distilled water) make them suitable for aqueous food storage. The extremely high solubility of SP and SLO in simulant B (acetic acid) shows that wax and hydrophobized starch, respectively are carried by the acidic media, thus these agents are unlikely to coat the paper designed to package acidic food. SLO inhibits E. coli, Salmonella enterica, Lysteria monocytogenes, Pseudomonas aeruginosa and fluorescens. Polyethylene coated on RO and IT surface and wax impregnated on SP have a lower antimicrobial activity in comparison with hydrophobized starch coated on SLO. [ABSTRACT FROM AUTHOR]

Habitat spatial structure has a profound influence on bacterial life, yet there currently are no low‐cost equipment‐free laboratory techniques to reproduce the intricate structure of natural bacterial habitats. Here, we demonstrate the use of paper scaffolds to create landscapes spatially structured at the scales relevant to bacterial ecology. In paper scaffolds, planktonic bacteria migrate through liquid‐filled pores, while the paper's cellulose fibres serve as anchor points for sessile colonies (biofilms). Using this novel approach, we explore bacterial colonisation dynamics in different landscape topographies and characterise the community composition of Escherichia coli strains undergoing centimetre‐scale range expansions in habitats structured at the micrometre scale. The bacteria‐in‐paper platform enables quantitative assessment of bacterial community dynamics in complex environments using everyday materials. [ABSTRACT FROM AUTHOR]

Switching between metabolically active and dormant states provides bacteria with protection from environmental stresses and allows rapid growth under favorable conditions. This rapid growth can be detrimental to the environment, e.g., pathogens in recreational lakes, or to industrial processes, e.g., fermentation, making it useful to quickly determine when the ratio of dormant to metabolically active bacteria changes. While a rapid increase in metabolically active bacteria can cause complications, a high number of dormant bacteria can also be problematic, since they can be more virulent and antibiotic-resistant. To determine the metabolic state of Escherichia coli and Salmonella Typhimurium, we developed two paper-based colorimetric assays. The color changes were based on oxidoreductases reducing tetrazolium salts to formazans, and alkaline phosphatases cleaving phosphates from nitrophenyl phosphate salt. Specifically, we added iodophenyl-nitrophenyl-phenyl tetrazolium salt (INT) and methylphenazinium methyl sulfate to metabolically active bacteria on paper and INT and para-nitrophenyl phosphate salt to dormant bacteria on paper. The color changed in less than 60 min and was generally visible at 10 CFU and quantifiable at 10 CFU. The color changes occurred in both bacteria, since oxidoreductases and alkaline phosphatases are common bacterial enzymes. On one hand, this feature makes the assays suitable to a wide range of applications, on the other, it requires specific capture, if only one type of bacterium is of interest. We captured Salmonella or E. coli with immobilized P22 or T4 bacteriophages on the paper, before detecting them at levels of 10 or 10 CFU, respectively. Determining the ratio of the metabolic state of bacteria or a specific bacterium at low cost and in a short time, makes this methodology useful in environmental, industrial and health care settings. [ABSTRACT FROM AUTHOR]

The capacity of Ag nanoparticles to destroy various micro‐organisms makes it one of the most powerful antimicrobial agents, an attractive feature against antibiotic resistant bacteria. Here, a simple method to develop coating of colloidal silver on paper using a biological method is presented. The coated paper was studied by scanning electron microscopy, X‐ray diffraction technique and atomic absorption spectroscopy. The antibacterial activity of the coated paper against Escherichia coli and Staphylococcus aureus was measured by agar diffusion method. This study shows the potential use of the coated paper as a food antimicrobial packing material for longer shelf life. [ABSTRACT FROM AUTHOR]

In this work, paper was rendered antimicrobial via applying antimicrobialmodified starch as a coating material onto the paper's surface. The antimicrobial starch was prepared by covalently bonding guanidine polymers using a coupling reaction. Two different coating layers were applied onto the paper's surface. The first coating layer contained clay mixed with a latex binder (clay 100 g/latex 20 g). The antimicrobial starches, which possessed different grafting ratios of the antimicrobial agent (30 wt.% and 50 wt.%), were applied as the second coating layer on the paper. The results showed that the coating thickness was approximately constant at 4 µm. In the presence of 0.5 to 1.0 wt.% antimicrobial starch on cellulose fibers, the growth inhibition of bacteria was almost 100%. Additionally, the resulting coated paper exhibited high antimicrobial activities against E. coli. Furthermore, the results showed that the coated papers prevented fungal growth. [ABSTRACT FROM AUTHOR]

• Waste paper was used to obtain nanocrystalline cellulose (CNC). • The obtained CNC was compared with CNC from cotton linter. • The biocidal activity of CNC added with Ag nanoparticles was assessed. • The growth of Aspergillus niger on Whatman paper is inhibited by CNC/Ag coating. • The mechanical properties of Whatman paper improve by the CNC coatings. Waste paper is an environmentally friendly source of cellulosic material. Here we propose a new treatment based on nanocrystalline cellulose (CNC) for paper preservation and consolidation. Suspensions of CNC were prepared by sulfuric acid hydrolysis using waste paper as cellulose source (CNC WP) and compared with CNC from cotton linter (CNC CL). Both CNCs were obtained with good yield, showing high crystallinity index and comparable morphology, as demonstrated by DLS-ELS, XRD, FTIR, Raman and TEM analyses. CNCs were mixed with silver nanoparticles (CNC/Ag) and their biocidal activity was tested against Escherichia coli and Bacillus subtilis , measuring the minimum inhibitory concentration. CNCs were exploited as treatments for biocidal activity and consolidation on Whatman paper. The presence of silver nanoparticles doesn't affect aesthetic appearance of the original paper and prevents the growth of Aspergillus niger fungus. Mechanical tests demonstrated that the coatings by CNC based products improve stretch and toughness of the paper support. [ABSTRACT FROM AUTHOR]