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Micromachines Sep 2020In this paper, we report on a novel biocompatible micromechanical bioreactor (actuator and sensor) designed for the in situ manipulation and characterization of live...
In this paper, we report on a novel biocompatible micromechanical bioreactor (actuator and sensor) designed for the in situ manipulation and characterization of live microtissues. The purpose of this study was to develop and validate an application-targeted sterile bioreactor that is accessible, inexpensive, adjustable, and easily fabricated. Our method relies on a simple polydimethylsiloxane (PDMS) molding technique for fabrication and is compatible with commonly-used laboratory equipment and materials. Our unique design includes a flexible thin membrane that allows for the transfer of an external actuation into the PDMS beam-based actuator and sensor placed inside a conventional 35 mm cell culture Petri dish. Through computational analysis followed by experimental testing, we demonstrated its functionality, accuracy, sensitivity, and tunable operating range. Through time-course testing, the actuator delivered strains of over 20% to biodegradable electrospun poly (D, L-lactide-co-glycolide) (PLGA) 85:15 non-aligned nanofibers (~91 µm thick). At the same time, the sensor was able to characterize time-course changes in Young's modulus (down to 10-150 kPa), induced by an application of isopropyl alcohol (IPA). Furthermore, the actuator delivered strains of up to 4% to PDMS monolayers (~30 µm thick), simultaneously characterizing their elastic modulus up to ~2.2 MPa. The platform repeatedly applied dynamic (0.23 Hz) tensile stimuli to live Human Dermal Fibroblast (HDF) cells for 12 hours (h) and recorded the cellular reorientation towards two angle regimes, with averages of -58.85° and +56.02°. The device biocompatibility with live cells was demonstrated for one week, with no signs of cytotoxicity. We can conclude that our PDMS bioreactor is advantageous for low-cost tissue/cell culture micromanipulation studies involving mechanical actuation and characterization. Our device eliminates the need for an expensive experimental setup for cell micromanipulation, increasing the ease of live-cell manipulation studies by providing an affordable way of conducting high-throughput experiments without the need to open the Petri dish, reducing manual handling, cross-contamination, supplies, and costs. The device design, material, and methods allow the user to define the operational range based on their targeted samples/application.
PubMed: 32993158
DOI: 10.3390/mi11100892 -
Journal of Cellular Biochemistry Nov 2019Petri dish cultured cells have for long provided scientists an aperture to understanding cell's behavior both in normal and disease states as well as in vitro and in... (Review)
Review
Petri dish cultured cells have for long provided scientists an aperture to understanding cell's behavior both in normal and disease states as well as in vitro and in vivo. But recent advances have brought to light how the architecture and composite nature of the immediate environment within which the cell is proliferated can profoundly influence its phenotypic features and functions, thus making obvious, limitations of the conventional two-dimensional cell culture despite it cost effectiveness. Fortunately, the transition to three-dimensional (3D) cell culture has occurred concurrently with expanded knowledge of nanoscience and materials, thereby lending significant impetus for innovative research. This review is focused on the application of nanoparticles in 3D stem cell breeding, recent trends and developments in medical sciences for improved drug delivery, and treatment approaches to some human diseases. We also reviewed prevailing challenges and concerns of nanotoxicity as it continues to impede and delay clinical applications as well the ongoing concerted and multidisciplinary efforts to overcome them.
Topics: Cell Culture Techniques; Cells, Cultured; Drug Delivery Systems; Humans; Nanomedicine; Nanoparticles; Nanostructures; Stem Cells
PubMed: 31364198
DOI: 10.1002/jcb.29133 -
Lab on a Chip Jul 2022Counting viable bacterial cells and functional bacteriophage is fundamental to microbiology underpinning research, surveillance, biopharmaceuticals and diagnostics....
Counting viable bacterial cells and functional bacteriophage is fundamental to microbiology underpinning research, surveillance, biopharmaceuticals and diagnostics. Colony forming unit (CFU) and plaque forming unit (PFU) counting still requires slow and laborious solid culture on agar in Petri dishes or plates. Here, we show that dip-stick microfluidic strips can be used without growth indicator dye for rapid and simple CFU ml and PFU ml measurement. We demonstrate for the first time that fluoropolymer microcapillaries combined with digital imaging allow bacteriophage plaques to be counted rapidly in a dip-and-test format. The microfluidic length scales offer a linear 1-dimensional alternative to a 2D solid agar medium surface, with colonies or plaques clearly visible as "dashes" or "gaps". An inexpensive open source darkfield biosensor system using Raspberry Pi imaging permits label-free detection and counting of colonies or plaques within 4-8 hours in a linear, liquid matrix within ∼200 μm inner diameter microcapillaries. We obtained full quantitative agreement between 1D microfluidic colony counting in dipsticks conventional 2D solid agar Petri dish plates for and , and for T2 phage and phage K, but up to 6 times faster. Time-lapse darkfield imaging permitted detailed kinetic analysis of colony growth in the microcapillaries, providing new insight into microfluidic microbiology and colony growth, not possible with Petri dishes. Surprisingly, whilst colonies appeared earlier, subsequent colony expansion was faster along the microcapillaries for . This may be explained by the microenvironment offered for 1D colony growth within microcapillaries, linked to a mass balance between nutrient (glucose) diffusion and bacterial growth kinetics. Counting individual colonies in liquid medium was not possible for motile strains that spread rapidly along the capillary, however inclusion of soft agar inhibited spreading, making this new simple dip-and-test counting method applicable to both motile and non-motile bacteria. Label-free dipstick colony and plaque counting has potential for many analytical microbial tasks, and the innovation of 1D colony counting has relevance to other microfluidic microbiology.
Topics: Agar; Bacteria; Bacteriophages; Colony Count, Microbial; Escherichia coli; Kinetics; Microfluidics; Staphylococcus aureus
PubMed: 35792607
DOI: 10.1039/d2lc00280a -
Scientific Reports Sep 2022In invasion scenarios, native and introduced species co-occur creating new interactions and modifying existing ones. Many plant-plant and plant-insect interactions are...
In invasion scenarios, native and introduced species co-occur creating new interactions and modifying existing ones. Many plant-plant and plant-insect interactions are mediated by volatile organic compounds (VOCs), however, these have seldom been studied in an invasion context. To fill this knowledge gap, we explored some interactions mediated by VOCs between native and introduced plants and insects in a New Zealand system. We investigated whether a native plant, Leptospermum scoparium (mānuka), changes its volatile profile when grown adjacent to two European introduced plants, Calluna vulgaris (heather) and Cytisus scoparius (Scotch broom), in a semi-field trial using potted plants without above- or below-ground physical contact. We also investigated the influence of plant cues on the host-searching behaviour of two beetles, the native Pyronota festiva (mānuka beetle), and the introduced biocontrol agent Lochmaea suturalis (heather beetle), by offering them their host-plant and non-host volatiles versus clean air, and their combination in a Y-tube olfactometer. As a follow-up, we performed preference/feeding tests in Petri dishes with fresh plant material. Results of the semi-field experiment show a significant reduction in green leaf volatiles, sesquiterpenes and total volatile emissions by mānuka plants neighbouring heather. In the Y-tube assays, the native beetle P. festiva performed poorly in discriminating between host and non-host plants based on plant volatile cues only. However, it performed relatively well in the Petri dish tests, where other cues (i.e., visual, gustatory or tactile) were present. In contrast, the introduced beetle L. suturalis showed high host-specificity in both Y-tube and Petri dish assays. This study illustrates the importance of VOCs in mediating interactions between introduced and native species, suggesting that invasive plants can disrupt native plants' communication and affect the host-searching behaviour of native insects. It also reinforces the relevance of regular host testing on introduced weed biocontrol agents to avoid unwanted host shifts or host-range expansion.
Topics: Animals; Coleoptera; Cytisus; Introduced Species; Plants; Volatile Organic Compounds
PubMed: 36104363
DOI: 10.1038/s41598-022-18479-z -
Proceedings of the ... IEEE/RSJ... Jan 2020This paper proposes a magnetic needle steering controller to manipulate mesoscale magnetic suture needles for executing planned suturing motion. This is an initial step...
This paper proposes a magnetic needle steering controller to manipulate mesoscale magnetic suture needles for executing planned suturing motion. This is an initial step towards our research objective: enabling autonomous control of magnetic suture needles for suturing tasks in minimally invasive surgery. To demonstrate the feasibility of accurate motion control, we employ a cardinally-arranged four-coil electromagnetic system setup and control magnetic suture needles in a 2-dimensional environment, i.e., a Petri dish filled with viscous liquid. Different from only using magnetic field gradients to control small magnetic agents under high damping conditions, the dynamics of a magnetic suture needle are investigated and encoded in the controller. Based on mathematical formulations of magnetic force and torque applied on the needle, we develop a kinematically constrained dynamic model that controls the needle to rotate and only translate along its central axis for mimicking the behavior of surgical sutures. A current controller of the electromagnetic system combining with closed-loop control schemes is designed for commanding the magnetic suture needles to achieve desired linear and angular velocities. To evaluate control performance of magnetic suture needles, we conduct experiments including needle rotation control, needle position control by using discretized trajectories, and velocity control by using a time-varying circular trajectory. The experiment results demonstrate our proposed needle steering controller can perform accurate motion control of mesoscale magnetic suture needles.
PubMed: 34457374
DOI: 10.1109/iros45743.2020.9341425 -
Pharmaceutics Mar 2022Orodispersible films (ODFs) have been widely used in paediatric, geriatric and dysphagic patients due to ease of administration and precise and flexible dose...
Orodispersible films (ODFs) have been widely used in paediatric, geriatric and dysphagic patients due to ease of administration and precise and flexible dose adjustments. ODF fabrication has seen significant advancements with the move towards more technologically advanced production methods. The acceptability of ODFs is dependent upon film composition and process of formation, which affects disintegration, taste, texture and mouthfeel. There is currently a lack of testing to accurately assess ODFs for these important acceptability sensory perceptions. This study produced four ODFs formed of polyvinyl alcohol and sodium carboxymethylcellulose using 3D printing. These were assessed using three in vitro methods: Petri dish and oral cavity model (OCM) methods for disintegration and bio-tribology for disintegration and oral perception. Increasing polymer molecular weight (MW) exponentially increased disintegration time in the Petri dish and OCM methods. Higher MW films adhered to the OCM upper palate. Bio-tribology analysis showed that films of higher MW disintegrated quickest and had lower coefficient of friction, perhaps demonstrating good oral perception but also stickiness, with higher viscosity. These techniques, part of a toolbox, may enable formulators to design, test and reformulate ODFs that both disintegrate rapidly and may be better perceived when consumed, improving overall treatment acceptability.
PubMed: 35456566
DOI: 10.3390/pharmaceutics14040732 -
Journal of Agricultural and Food... Dec 2020Based on the structures of isoxaflutole (IFT) and -isobutyl--(4-chloro-benzyl)-4-chloro-2-pentenamide, a series of -benzyl-5-cyclopropyl-isoxazole-4-carboxamides was...
Based on the structures of isoxaflutole (IFT) and -isobutyl--(4-chloro-benzyl)-4-chloro-2-pentenamide, a series of -benzyl-5-cyclopropyl-isoxazole-4-carboxamides was designed by connecting their pharmacophores (, a multitarget drug design strategy). A total of 27 -benzyl-5-cyclopropyl-isoxazole-4-carboxamides were prepared from 5-cyclopropylisoxazole-4-carboxylic acid and substituted benzylamines, and their structures were confirmed by NMR and MS. Laboratory bioassays indicated that showed 100% inhibition against and at a concentration of 10 mg/L, better than the positive control butachlor (50% inhibition for both weeds). A strong growth inhibition was observed, but a typical bleaching phenomenon of IFT could not be observed in the Petri dish assay. displayed excellent postemergence herbicidal activity against and at a rate of 150 g/ha, and bleaching symptoms were observed in the leaves of treated weeds. The bleaching effect of treated by could be reversed by adding homogentisate. Enzymatic bioassays indicated that could not inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD) activity, but , an isoxazole ring-opening product of , could inhibit HPPD activity with an EC value of 1.05 μM, similar to that of mesotrione (with an EC value of 1.35 μM). Detailed discussion about observed herbicidal symptoms is provided in the Results and Discussion section. This investigation provided a proof-of-concept foundation that a multitarget drug design strategy could be applied in agrochemical research.
Topics: Drug Design; Echinochloa; Herbicides; Isoxazoles; Molecular Structure; Plant Weeds; Structure-Activity Relationship
PubMed: 33301336
DOI: 10.1021/acs.jafc.0c03582 -
Zootaxa Sep 2022The life history of Erotylina jaspidea (Erichson, 1847) (Coleoptera, Erotyloidea, Erotylidae, Erotylini) is described. A female specimen was found in an Atlantic Forest...
The life history of Erotylina jaspidea (Erichson, 1847) (Coleoptera, Erotyloidea, Erotylidae, Erotylini) is described. A female specimen was found in an Atlantic Forest remnant in Northeast Brazil. After oviposition, individuals were reared in Petri dish and terrarium, feeding on basidiomes of Lentinus substrictus (Bolton) Zmitr. Kovalenko, Favolus tenuiculus P. Beauv (Polyporaceae) and an unidentified resupinate fungus. Growth and feeding behaviors were regularly observed. We provide information on the observed life history stages, together with morphological descriptions, and photographs of eggs, larvae, pupae and adults. We compared our description of the teneral E. jaspidea to species of similar color pattern. Furthermore, we discuss hypotheses about larval defensive behavior and total instar durations in E. jaspidea and other Erotylinae representatives. The present work is the first to provide a description for the life history of a species of the genus Erotylina.
Topics: Animals; Coleoptera; Female; Forests; Larva; Oviposition; Pupa
PubMed: 36095671
DOI: 10.11646/zootaxa.5182.5.6 -
Environmental Science & Technology Aug 2023Microorganisms colonizing the surfaces of microplastics form a plastisphere in the environment, which captures miscellaneous substances. The plastisphere, owning to its... (Review)
Review
Microorganisms colonizing the surfaces of microplastics form a plastisphere in the environment, which captures miscellaneous substances. The plastisphere, owning to its inherently complex nature, may serve as a "Petri dish" for the development and dissemination of antibiotic resistance genes (ARGs), adding a layer of complexity in tackling the global challenge of both microplastics and ARGs. Increasing studies have drawn insights into the extent to which the proliferation of ARGs occurred in the presence of micro/nanoplastics, thereby increasing antimicrobial resistance (AMR). However, a comprehensive review is still lacking in consideration of the current increasingly scattered research focus and results. This review focuses on the spread of ARGs mediated by microplastics, especially on the challenges and perspectives on determining the contribution of microplastics to AMR. The plastisphere accumulates biotic and abiotic materials on the persistent surfaces, which, in turn, offers a preferred environment for gene exchange within and across the boundary of the plastisphere. Microplastics breaking down to smaller sizes, such as nanoscale, can possibly promote the horizontal gene transfer of ARGs as environmental stressors by inducing the overgeneration of reactive oxygen species. Additionally, we also discussed methods, especially quantitatively comparing ARG profiles among different environmental samples in this emerging field and the challenges that multidimensional parameters are in great necessity to systematically determine the antimicrobial dissemination risk in the plastisphere. Finally, based on the biological sequencing data, we offered a framework to assess the AMR risks of micro/nanoplastics and biocolonizable microparticles that leverage multidimensional AMR-associated messages, including the ARGs' abundance, mobility, and potential acquisition by pathogens.
Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Microplastics; Plastics; Gene Transfer, Horizontal
PubMed: 37578142
DOI: 10.1021/acs.est.3c01128 -
Gels (Basel, Switzerland) May 2023Macroscopic spatial patterns were formed in calcium alginate gels when a drop of a calcium nitrate solution was placed on the center of a sodium alginate solution on a...
Macroscopic spatial patterns were formed in calcium alginate gels when a drop of a calcium nitrate solution was placed on the center of a sodium alginate solution on a petri dish. These patterns have been classified into two groups. One is multi-concentric rings consisting of alternating cloudy and transparent areas observed around the center of petri dishes. The other is streaks extending to the edge of the petri dish, which are formed to surround the concentric bands between the concentric bands and the petri dish edge. We have attempted to understand the origins of the pattern formations using the properties of phase separation and gelation. The distance between two adjacent concentric rings was roughly proportional to the distance from where the calcium nitrate solution was dropped. The proportional factor increased exponentially for the inverse of the absolute temperature of the preparation. The also depended on the concentration of alginate. The pattern characteristics in the concentric pattern agreed with those in the Liesegang pattern. The paths of radial streaks were disturbed at high temperatures. The length of these streaks shortened with increasing alginate concentration. The characteristics of the streaks were similar to those of crack patterns resulting from inhomogeneous shrinkage during drying.
PubMed: 37367115
DOI: 10.3390/gels9060444