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Introduction: Acanthamoeba spp . are free-living parasites increasingly implicated in causing Acanthamoeba keratitis (AK). AK is diagnosed by demonstration of parasites in corneal samples by direct microscopy, culture, and nucleic acid amplification. Most commonly, corneal scrapings are sent to the laboratory smeared between two glass slides. These scrapings are suitable for direct microscopy but less suitable for culture and polymerase chain reaction (PCR) which, in turn, are more sensitive for the diagnosis of AK., Aim: The aim of the study was to explore better alternatives for transporting corneal scrapings from the point-of-care eye center to the concerned laboratories., Materials and Methods: The study used small Parafilm (Bemis Company Inc., USA) squares (PSs) of 1 cm each prepared by cutting Parafilm using a surgical blade under sterile conditions. Each of the four different dilutions of Acanthamoeba suspension (15, 30, 60, and 120 cells) was used in this study. Each dilution was added onto the surface of 36 PSs and kept at room temperature for 24-h, 48-h, and 72-h incubation. The PSs for one particular time point and dilution were used for calcofluor white staining, its inoculation onto the surface of nonnutrient agar having a lawn of Escherichia coli , and Acanthamoeba -specific PCR amplification. In addition, two PSs inoculated with 30 cells and incubated for 24 h and 72 h were used for scanning electron microscopy (SEM)., Results and Conclusion: All three diagnostic techniques, i.e. microscopy, culture, and PCR, detected the presence of Acanthamoeba at all the tested concentrations and time points. However, the growth pattern on culture changed directly in proportion to increased incubation periods and increased concentration of inoculum. In addition, the adherence of Acanthamoeba to the Parafilm was confirmed by SEM; these results suggest the use of these PSs as a suitable matrix for the transport of corneal scrapings., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Tropical Parasitology.)

A reliable encapsulation technology with scalability and flexibility is urgently needed for electroluminescence devices. Here, we developed a simple, robust, low-cost, and scalable flexible lamination encapsulation strategy with quantum-dot light-emitting diodes (QLEDs) as the model devices. Multilayered Parafilm combining with calcium oxide buffer was used for the lamination encapsulation. We successfully demonstrated that such a Parafilm Lami encapsulation (PLE) not only allowed excellent protection for QLEDs in air but endowed QLED outstanding waterproof performance. As a result, highly efficient and stable flexible waterproof QLEDs were realized based on this PLE, exhibiting maximum external quantum efficiency of ∼8% and long half-luminescence lifetime of over 1.5 h in water. We believe that there are not any obstacles to extending this encapsulation technology to other flexible flat-panel devices, such as organic/perovskite light-emitting diodes.

Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein, we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied and optimized the effect of the key fabrication parameters, namely pressure, temperature, and pressing time. We discerned the optimal conditions, including a pressure of 3.8 MPa, temperature of 80 °C, and 3 min of pressing time, with the smallest hydrophobic barrier size (821 µm) being governed by laminate mask and parafilm dispersal from pressure and heat. Physical and biochemical properties were evaluated to substantiate the paper functionality for analytical devices. The wicking speed in the fabricated paper strips was slightly lower than that of non-processed paper, resulting from a reduced paper pore size after hot pressing. A colorimetric immunological assay was performed to demonstrate the protein binding capacity of the paper-based device after exposure to pressure and heat from the fabrication. Moreover, mixing in a two-dimensional paper-based device and flowing in a three-dimensional counterpart were thoroughly investigated, demonstrating that the paper devices from this fabrication process are potentially applicable as analytical devices for biomolecule detection. Fast, easy, and inexpensive parafilm hot press fabrication presents an opportunity for researchers to develop paper-based analytical devices in resource-limited environments.

The application of desorption electrospray ionization mass spectrometry (DESI-MS) and dried blood spot (DBS) sampling has been successfully implemented several times. However, the difficulty of combining DBS sampling with DESI-MS is still the carrier material used for the blood samples. In this study, a new, easily obtained, and cost-effective carrier substrate for dried plasma spot (DPS) sampling and DESI-MS analysis and its application in phospholipidomics studies was described. First, the effects of several carrier materials, including cellulose-based materials (31 ET paper and filter paper) and non-cellulose-based materials (PARAFILM and its shape-modified material, PTFE-printed glass slide and polyvinylidene fluoride film), were tested. Second, a method combining DPS sampling with DESI-MS for phospholipidomics analysis was established, and parameters affecting compound signal intensities, such as sample volume and sprayer solvent system, were optimized. In conclusion, the total signal intensity obtained from shape-modified PARAFILM was the strongest. The suitable plasma sample volume deposited on PARAFILM carriers was 5 μl, and acetonitrile (ACN) was recommended as the optimal spray solvent for phospholipid (PL) profiling. Repeatability (87.5% of compounds with CV < 30%) and stability for data acquisition (48 h) were confirmed. Finally, the developed method was applied in phospholipidomics analysis of schistosomiasis, and a distinguished classification between control mice and infected mice was observed by using multivariate pattern recognition analysis, confirming the practical application of this new carrier material for DPS sampling and DESI-MS analysis. Compared with a previously reported method, the rapid metabolomics screening approach based on the implementation of DPS sampling coupled with the DESI-MS instrument developed in this study has increased analyte sensitivity, which may promote its further application in clinical studies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Hu, Shao, Zhou and Lv.)

Context: Acanthamoeba is increasingly implicated in causing keratitis in patients wearing contact lens or ocular trauma and has a poor prognosis. Establishment of an animal model is critical to study the disease pathology, pathogenesis and to evaluate anti-amoebic drugs. Some studies have used contact lenses to establish Acanthamoeba keratitis (AK) in a mouse model, which is expensive and not very successful as lenses get dislodged., Objective: To assess the feasibility of using parafilm (Bemis Company Inc., USA) as an alternative to contact lens for the establishment of AK in the mouse model., Methods: Thirty-six Balb/c mice in three groups of six mice each for two strains of Acanthamoeba were used to induce AK. Three experimental approaches used were; i) Acanthamoeba impregnated contact lens, ii) Acanthamoeba impregnated parafilm and iii) scratching followed by inoculation of Acanthamoeba suspension. In all three models, tarsorrhaphy was performed. Infection was evaluated by clinical examination and also through microscopic examination of corneal scrapings and corneal sections., Results: AK model was successfully established with parafilm whereas only one mouse developed AK with the use of contact lens and none with scratching and Acanthamoeba inoculation., Conclusion: The use of parafilm is convenient, reliable and cheaper and can be considered an alternative to contact lenses to induce AK in a mouse model., Competing Interests: Declaration of competing interest None., (Copyright © 2021 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.)

Hypothesis: Evaporation of surfactant droplets on leaves is complicated due to the complex physical and chemical properties of the leaf surfaces. However, for certain leaf surfaces for which the evaporation process appears to follow the standard constant-contact-radius or constant-contact-angle modes, it should be possible to mimic the droplet evaporation with both a well-chosen synthetic surface and a relatively simple mathematical model., Experiments: Surfactant droplet evaporation experiments were performed on two commercial crop species, wheat and capsicum, along with two synthetic surfaces, up to a 90° incline. The time-dependence of the droplets' contact angles, height, volume and contact radius was measured throughout the evaporation experiments. Mathematical models were developed to simulate the experiments., Findings: With one clear exception, for all combinations of surfaces, surfactant concentrations and angles, the experiments appear to follow the standard evaporation modes and are well described by the mathematical models (modified Popov and Young-Laplace-Popov). The exception is wheat with a high surfactant concentration, for which droplet evaporation appears nonstandard and deviates from the diffusion limited models, perhaps due to additional mechanisms such as the adsorption of surfactant, stomatal density or an elongated shape in the direction of the grooves in the wheat surface., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Parafilm M ® is a moisture-resistant thermoplastic commonly used to seal Nematode Growth Media (NGM) agar plates on which the nematode Caenorhabditis elegans is cultured. This practice reduces media dehydration and microbial contamination. However, the effects on C. elegans individuals of placing this barrier between the external environment and the interior of the NGM plate are currently unknown. Our research aims to determine if this common practice engenders developmental changes, such as growth, that could subsequently and unintentionally alter experimental data. We compared the larval growth over 48 h of animals cultured on Parafilm-wrapped and unwrapped control NGM plates., Results: Wrapping culture plates with Parafilm significantly accelerated and increased larval growth, with a 0.87 μm/h increase in growth rate (~ 6%) and a 37.90 μm increase in the change in growth (Δgrowth; ~ 5%) over 48 h. Therefore, C. elegans investigators should be aware that wrapping their experimental cultures with Parafilm may result in statistically detectable changes in worm growth and possibly other developmental processes.

We report a versatile strategy to exploit parafilm waste as a carbon precursor for fabrication of freestanding, hollow few-layer graphene fiber mesh (HFGM) structures without use of any gaseous carriers/promoters via an annealing route. The freestanding HFGMs possess good mechanical flexibility, tailorable transparency, and high electrical conductivity, consequently qualifying them as promising electrochemical electrodes. Because of the hollow spaces, electrolyte ions can easily access into and contact with interior surfaces of the graphene fibers, accordingly increasing electrode/electrolyte interfacial area. As expected, solid-state supercapacitors based on the HFGMs exhibit a considerable enhancement in specific capacitance (20-30 fold) as compared to those employing chemical vapor deposition compact graphene films. Moreover, the parafilm waste is found to be beneficial for one-step fabrication of nanocarbon/few-layer graphene composite meshes with superior electrochemical performance, outstanding superhydrophobic property, good self-cleaning ability, and great promise for oil spill cleanup.

Herein, we evaluated the use of paper towel, waxed paper, and Parafilm M ® (Heathrow Scientific, Vernon Hills, IL, USA) as alternative substrates for screen-printed sensor manufacturing. Morphological study was performed to evaluate the adhesion of the ink on these uncommon substrates, as well as the morphology of the working electrode. The electrochemical characterization was carried out using ferricyanide/ferrocyanide as redox couple. To enhance the electrochemical properties of the developed sensors, the nanomaterial carbon black was used as nanomodifier. The modification by drop casting of the working electrode surface, using a stable dispersion of carbon black, allows to obtain a sensor with improved electrochemical behavior in terms of peak-to-peak separation, current intensity, and the resistance of charge transfer. The results achieved confirm the possibility of printing the electrode on several cost-effective paper-based materials and the improvement of the electrochemical behavior by using carbon black as sustainable nanomaterial., Competing Interests: The authors declare no conflict of interest.

Proteins and other biomolecules such as lipids are significant players in the central nervous system and are implicated in various neurological disorders. Their identification, quantification, and distribution are thus important not only in understanding the disease but also in developing treatments. A combined workflow allowing the localized microextraction of discrete regions identified by a matrix-assisted laser desorption/ionization mass spectrometry (MSI) imaging experiment for proteomics analysis by liquid chromatography/tandem mass spectrometry (LC MS/MS) is described in this chapter. MSI was initially used to map lipid distributions allowing for the identification of regions of interest (ROIs) that are then subjected to microextraction in a consecutive tissue section. Mounting of consecutive tissue on parafilm allows microdissection of the ROIs, where proteins can then be recovered for processing and LC MS/MS analysis. The PAM method provides a fast and cheap means to perform further downstream analysis after an MSI experiment.