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Microbial surface attachment negatively impacts a wide range of devices from water purification membranes to biomedical implants. Mimics of antimicrobial peptides (AMPs) constituted from poly(N-substituted glycine) "peptoids" are of great interest as they resist proteolysis and can inhibit a wide spectrum of microbes. We investigate how terminal modification of a peptoid AMP-mimic and its surface immobilization affect antimicrobial activity. We also demonstrate a convenient surface modification strategy for enabling alkyne-azide "click" coupling on amino-functionalized surfaces. Our results verified that the N- and C-terminal peptoid structures are not required for antimicrobial activity. Moreover, our peptoid immobilization density and choice of PEG tether resulted in a "volumetric" spatial separation between AMPs that, compared to past studies, enabled the highest AMP surface activity relative to bacterial attachment. Our analysis suggests the importance of spatial flexibility for membrane activity and that AMP separation may be a controlling parameter for optimizing surface anti-biofouling.

We propose a smartphone‐based optical sectioning (SOS) microscope based on the HiLo technique, with a single smartphone replacing a high‐cost illumination source and a camera sensor. We built our SOS with off‐the‐shelf optical, mechanical cage systems with 3D‐printed adapters to seamlessly integrate the smartphone with the SOS main body. The liquid light guide can be integrated with the adapter, guiding the smartphone's LED light to the digital mirror device (DMD) with neglectable loss. We used an electrically tuneable lens (ETL) instead of a mechanical translation stage to realise low‐cost axial scanning. The ETL was conjugated to the objective lens's back pupil plane (BPP) to construct a telecentric design by a 4f configuration to maintain the lateral magnification for different axial positions. SOS has a 571.5 µm telecentric scanning range and an 11.7 µm axial resolution. The broadband smartphone LED torch can effectively excite fluorescent polystyrene (PS) beads. We successfully used SOS for high‐contrast fluorescent PS beads imaging with different wavelengths and optical sectioning imaging of multilayer fluorescent PS beads. To our knowledge, the proposed SOS is the first smartphone‐based HiLo optical sectioning microscopy (£1965), which can save around £7035 compared with a traditional HiLo system (£9000). It is a powerful tool for biomedical research in resource‐limited areas. LAY DESCRIPTION: We have developed a new type of microscope called the Smartphone‐based Optical Sectioning (SOS) microscope, which uses a common smartphone to replace expensive traditional components. This innovative microscope is constructed from readily available parts along with 3D‐printed adapters, making it easy to assemble. The smartphone's LED light is directed precisely with minimal loss to illuminate samples, and instead of using bulky mechanical parts, we employ an adjustable lens to focus on different depths within a sample. This design allows us to maintain clear, consistent magnifications across various depths. Our SOS microscope offers a significant cost advantage, costing just under ₣2,000, compared to the ₣9,000 price tag of conventional microscopes with similar capabilities. This makes it especially valuable for conducting high‐quality biomedical research in places where resources and access to expensive equipment are limited. The microscope can produce high‐contrast images of fluorescent samples, showing details down to the cellular level. This breakthrough could greatly enhance research opportunities in many parts of the world. [ABSTRACT FROM AUTHOR]

Far-ultraviolet C light, with a wavelength of 200–230 nm, has demonstrated broad-spectrum germicidal efficacy. However, due to increased interest in its use as an alternative antimicrobial, further knowledge about its fundamental bactericidal efficacy is required. This study had two objectives. Firstly, it investigated experimentally the Far-UVC dose–response of common bacteria suspended at various cell densities in transparent buffer, ensuring no influence from photosensitive suspending media. Increasing doses of Far-UVC were delivered to Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in PBS at 101, 102, 103, 105 and 107 CFU·mL−1, with surviving colony-forming units enumerated (n ≥ 3). Secondly, through a systematised literature review, this work sought to explore the impact of genus/species, Gram type, cell form, cell density and irradiance on dose–response. The screening of 483 publications was performed with 25 included in the study. Data for 30 species were collated, analysed and compared with the experimental results. Overall, Gram-positive species showed greater resilience to Far-UVC than Gram-negative; some inter-species and inter-genera differences in resilience were identified; endospores were more resilient than vegetative cells; the results suggested that inactivation efficiency may decrease as cell density increases; and no significant correlation was identified between irradiance and bactericidal dose effect. In conclusion, this study has shown Far-UVC light to be an effective decontamination tool against a vast range of bacterial vegetative cells and endospores. [ABSTRACT FROM AUTHOR]

Violet–blue light of 405 nm in the visible spectrum at a dose of 270 J/cm2 alone has been shown to be an effective microbicidal tool for inactivating several bacteria, HIV-1, and Trypanosoma cruzi in ex vivo plasma and platelets. Unlike chemical- and ultraviolet (UV)-based pathogen inactivation methods for plasma and platelet safety, 405 nm light is shown to be less toxic to host cells at light doses that are microbicidal. In this report, we evaluated the parasiticidal activity of a 405 nm light treatment on platelets spiked with the Leishmania donovani parasite. Following the light treatment, parasite viability was observed to be near zero in both low- and high-titer-spiked platelets relative to controls. Furthermore, to test the residual infectivity after inactivation in vivo, the light-treated low-titer L. donovani-spiked platelets were evaluated in an immunodeficient Rag2−/− mouse model and monitored for 9 weeks. The parasiticidal efficacy of 405 nm light was evident from the lack of a presence of parasites in the mice spleens. Parasiticidal activity was confirmed to be mediated through 405 nm light-induced reactive oxygen species (ROS), as quantitatively measured by a 2′,7′-Dichlorodihydrofluorescein diacetate (H2DCFDA)-based assay. Overall, these results confirm the complete inactivation of L. donovani spiked in ex vivo platelets by 405 nm light treatment and exemplify the utility of the Rag2−/− mouse infection model for the preclinical validation of the parasiticidal efficacy of 405 nm light and this light-based technology as a potential PRT for ex vivo platelets. [ABSTRACT FROM AUTHOR]

Science educators are often among the first to use emerging technologies in the classroom and laboratory. For the technologically savvy science teacher, the handheld computer is a terrific tool. A handheld computer is a portable electronic device that helps organize (via calendars, contact lists, to-do lists) and integrate electronic data (documents, spreadsheets, media, e-mail, companion software) into the mobile lifestyle of busy professionals and many students. Handheld devices have long had the potential for applications in the classroom, but recent advances and affordability in wireless technologies have enhanced their applicability in schools and created opportunities for educators to improve on process and management efficiencies. This article discusses the useful applications of handheld computers in the classroom: (1) streamlining attendance and grading; (2) assessing student work during laboratory exercises; (3) managing cooperative learning; (4) minimizing data synchronization operations; and (5) freeing up time. (Contains 1 figure and 3 resources.)