An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

Advancement and challenges in sample preparation for atomic force microscopy and infrared microscopy for wood-based materials

Wood-based materials such as composites or laminates play an important role in today's furniture industry, especially in manufacturing high-quality kitchen and dining room furniture. One important aspect after fabrication is the investigation of these materials to derive quality metrics such as surface stain and scuff resistance. Current sample preparation methods are mostly straightforward and rely on cutting and grinding the materials under test, including sensitive wood substrates. To investigate cross-sections and different layer topologies, characterisation techniques such as atomic force microscopy (AFM) and infrared (IR) microscopy are of potential interest. However, a huge limitation is that current sample preparation methods lead to smeared coatings on the sample cross-sections and high surface roughness. Hence, these methods are not applicable for the sample preparation in measuring AFM and IR microscopy. Therefore, new preparation techniques need to be developed accordingly. This article presents a new approach towards coated wood-based sample preparation including embedding processes to use those samples for AFM and IR microscopy technologies. The proposed method has been evaluated by obtaining AFM, IR and microscopy measurements of more than four different wood-based samples such as (i) raw paper, (ii) impregnated paper, (iii) melamine-coated chipboards and (iv) medium-density fibreboards. The investigation results showed a significant improvement in sample preparation, as well as clear chemical and physical characterisation over whole sample construction, including coating layers, for wood-based materials.

Imaging Techniques for Detecting Prokaryotic Viruses in Environmental Samples

Viruses are the most abundant biological entities on Earth with an estimate of 1031 viral particles across all ecosystems. Prokaryotic viruses-bacteriophages and archaeal viruses-influence global biogeochemical cycles by shaping microbial communities through predation, through the effect of horizontal gene transfer on the host genome evolution, and through manipulating the host cellular metabolism. Imaging techniques have played an important role in understanding the biology and lifestyle of prokaryotic viruses. Specifically, structure-resolving microscopy methods, for example, transmission electron microscopy, are commonly used for understanding viral morphology, ultrastructure, and host interaction. These methods have been applied mostly to cultivated phage-host pairs. However, recent advances in environmental genomics have demonstrated that the majority of viruses remain uncultivated, and thus microscopically uncharacterized. Although light- and structure-resolving microscopy of viruses from environmental samples is possible, quite often the link between the visualization and the genomic information of uncultivated prokaryotic viruses is missing. In this minireview, we summarize the current state of the art of imaging techniques available for characterizing viruses in environmental samples and discuss potential links between viral imaging and environmental genomics for shedding light on the morphology of uncultivated viruses and their lifestyles in Earth's ecosystems.

Nanoemulsion-based delivery approaches for nutraceuticals: fabrication, application, characterization, biological fate, potential toxicity and future trends

In the modern food industry, people are paying more and more attention to the use of edible nanoemulsions to encapsulate, protect and deliver lipophilic functional ingredients, such as volatile additives, polyphenols, aromas, pigments, proteins, vitamins, oil-soluble flavors, preservatives, etc., which are the current global needs. Nanoemulsions are constructed with droplets of nano range size and they offer many potential advantages over conventional emulsions including the delivery of both hydrophilic and hydrophobic compounds, higher stability, better antibacterial properties, good taste experience, higher affinity, longer shelf-life and improvement of the bioavailability of components. Moreover, they are highly capable of improving the wettability and/or solubility of poorly water-soluble compounds, which may result in better pharmacokinetic and pharmacodynamic properties of nutraceutical compounds. On the other hand, oral nanoemulsions also have certain risks, such as their ability to change the biological fate of biologically active ingredients in the gastrointestinal tract and the potential toxicity of certain ingredients used in their production. This review article summarizes the manufacturing, application, characterization, biological fate, potential toxicity, and future challenges and trends of nanoemulsions, and focuses on nanoemulsion-based nutraceutical delivery approaches suitable for the food industry.