Bio-based antibacterial seed treatments to improve soil and plant health.

The only current treatments for bacterial diseases are copper compounds and antibiotics, both of which have resistance issues. This project demonstrated the proof of concept that bacteriophages can be incorporated into seed treatment polymers, coated on seed and stored for long periods of time without losing activity

Measuring Markers of Liver Function Using a Micropatterned Paper Device Designed for Blood from a Fingerstick

This paper describes a paper-based microfluidic device that measures two enzymatic markers of liver function (alkaline phosphatase, ALP, and aspartate aminotransferase, AST) and total serum protein. A device consists of four components: (i) a top plastic sheet, (ii) a filter membrane, (iii) a patterned paper chip containing the reagents necessary for analysis, and (iv) a bottom plastic sheet. The device performs both the sample preparation (separating blood plasma from erythrocytes) and the assays; it also enables both qualitative and quantitative analysis of data. The data obtained from the paper-microfluidic devices show standard deviations in calibration runs and “spiked” standards that are acceptable for routine clinical use. This device illustrates a type of test useable for a range of assays in resource-poor settings.Chemistry and Chemical Biolog

A Simple Two-Dimensional Model System to Study Electrostatic-Self-Assembly

This paper surveys the variables controlling the lattice structure and charge in macroscopic Coulombic crystals made from electrically charged, millimeter-sized polymer objects (spheres, cubes, and cylinders). Mechanical agitation of these objects inside planar, bounded containers caused them to charge electrically through contact electrification, and to self-assemble. The processes of electrification and self-assembly, and the characteristics of the assemblies, depended on the type of motion used for agitation, on the type of materials used for the objects and the dish, on the size and shape of the objects and the dish, and on the number of objects. Each of the three different materials in the system (of the dish and of the two types of spheres) influenced the electrification. Three classes of structures formed by self-assembly, depending on the experimental conditions: two-dimensional lattices, one-dimensional chains, and zero-dimensional ‘rosettes’. The lattices were characterized by their structure (disordered, square, rhombic, or hexagonal) and by the electrical charges of individual objects; the whole lattices were approximately electrically neutral. The lattices observed in this study were qualitatively different from ionic crystals; the charge of objects had practically continuous values which changed during agitation and self-assembly, and depended on experimental conditions which included the lattice structure itself. The relationship between charge and structure led to the coexistence of regions with different lattice structures within the same assembly, and to transformations between different lattice structures during agitation.Chemistry and Chemical Biolog

Rethinking the Design of Low-Cost Point-of-Care Diagnostic Devices

Reducing the global diseases burden requires effective diagnosis and treatment. In the developing world, accurate diagnosis can be the most expensive and time-consuming aspect of health care. Healthcare cost can, however, be reduced by use of affordable rapid diagnostic tests (RDTs). In the developed world, low-cost RDTs are being developed in many research laboratories; however, they are not being equally adopted in the developing countries. This disconnect points to a gap in the design philosophy, where parameterization of design variables ignores the most critical component of the system, the point-of-use stakeholders (e.g., doctors, nurses and patients). Herein, we demonstrated that a general focus on reducing cost (i.e., “low-cost”), rather than efficiency and reliability is misguided by the assumption that poverty reduces the value individuals place on their well-being. A case study of clinicians in Kenya showed that “zero-cost” is a low-weight parameter for point-of-use stakeholders, while reliability and standardization are crucial. We therefore argue that a user-driven, value-addition systems-engineering approach is needed for the design of RDTs to enhance adoption and translation into the field

Simple and fast detection of E. coli in agricultural water sources and runoff

Investigators conducted experiments on the viability of new, quicker tests for the presence of E.Coli in water supplies. their preliminary data suggested that bacteriophages (viruses infecting bacteria) offer potential for detection of bacteria if the right medium can be found for testing.</p

Bio-based antibacterial seed treatments to improve soil and plant health.

The only current treatments for bacterial diseases are copper compounds and antibiotics, both of which have resistance issues. This project demonstrated the proof of concept that bacteriophages can be incorporated into seed treatment polymers, coated on seed and stored for long periods of time without losing activity.</p

The use of biological seed coatings based on bacteriophages and polymers against Clavibacter michiganensis subsp. nebraskensis in maize seeds

Biological control of bacteria with bacteriophages is a viable alternative to antibiotics. To be successful, biological control bacteriophages must be stable when exposed to the environment. Stabilization can be achieved through incorporation of bacteriophages into polymers and stabilizers that will be coated onto the seed. For this study, bacteriophages against Clavibacter michiganensis subsp. nebraskensis (Cmn), the causal agent of Goss’s wilt, were incorporated into polyvinyl polymers with alcohol, ether and pyrrolidone functional groups and coated onto maize (Zea mays L.) seeds. The objectives of this study were to evaluate polymers and stabilizers that can protect Clavibacter michiganensis subsp. nebraskensis (CN8) bacteriophages against dehydration during storage. Bacteriophages stability when coated on seed depended on the glass transition temperature (Tg), functional groups of the polymer, and the presence of stabilizers such as sugars and proteins. Polyvinyl alcohol (PVOH) provided the greatest stability for CN8 bacteriophages on seed when coatings did not contain a stabilizer. A possible reason for the greater stability of this coating is having a glass transition temperature (Tg) very close to ambient temperature. PVOH combined with whey protein isolate (WPI) maintained CN8 bacteriophage activity in storage for four months at 26 °C and seven months at 10 °C. This coating also significantly reduced bacterial loads in seedlings grown from contaminated seeds, without affecting seed germination. Bacteriophage-polymer coatings which are stable during drying and storage, and are compatible with biological systems, not only provide an alternative to traditional antibiotics in agriculture, but also provide options for food, environmental and medical applications.This article is published as Kimmelshue, C., Goggi, A.S. & Cademartiri, R. The use of biological seed coatings based on bacteriophages and polymers against Clavibacter michiganensis subsp. nebraskensis in maize seeds. Sci Rep 9, 17950 (2019) doi: 10.1038/s41598-019-54068-3.</p

Rethinking the Design of Low-Cost Point-of-Care Diagnostic Devices

Reducing the global diseases burden requires effective diagnosis and treatment. In the developing world, accurate diagnosis can be the most expensive and time-consuming aspect of health care. Healthcare cost can, however, be reduced by use of affordable rapid diagnostic tests (RDTs). In the developed world, low-cost RDTs are being developed in many research laboratories; however, they are not being equally adopted in the developing countries. This disconnect points to a gap in the design philosophy, where parameterization of design variables ignores the most critical component of the system, the point-of-use stakeholders (e.g., doctors, nurses and patients). Herein, we demonstrated that a general focus on reducing cost (i.e., “low-cost”), rather than efficiency and reliability is misguided by the assumption that poverty reduces the value individuals place on their well-being. A case study of clinicians in Kenya showed that “zero-cost” is a low-weight parameter for point-of-use stakeholders, while reliability and standardization are crucial. We therefore argue that a user-driven, value-addition systems-engineering approach is needed for the design of RDTs to enhance adoption and translation into the field.This article is published as F. W. Kimani, S. M. Mwangi, B. J. Kwasa, A. M. Kusow, B. K. Ngugi, J. Chen, X. Liu, R. Cademartiri, and M. M. Thuo “Rethinking the Design of Low-Cost Point-Of-Care Diagnostic Devices” Micromachines 2017, 8(11), 317; DOI: 10.3390/mi8110317. Posted with permission.</p

Charging of Multiple Interacting Particles by Contact Electrification

Many processes involve the movement of a disordered collection of small particles (e.g., powders, grain, dust, and granular foods). These particles move chaotically, interact randomly among themselves, and gain electrical charge by contact electrification. Understanding the mechanisms of contact electrification of multiple interacting particles has been challenging, in part due to the complex movement and interactions of the particles. To examine the processes contributing to contact electrification at the level of single particles, a system was constructed in which an array of millimeter-sized polymeric beads of different materials were agitated on a dish. The dish was filled almost completely with beads, such that beads did not exchange positions. At the same time, during agitation, there was sufficient space for collisions with neighboring beads. The charge of the beads was measured individually after agitation. Results of systematic variations in the organization and composition of the interacting beads showed that three mechanisms determined the steady-state charge of the beads: (i) contact electrification (charging of beads of different materials), (ii) contact de-electrification (discharging of beads of the same charge polarity to the atmosphere), and (iii) a long-range influence across beads not in contact with one another (occurring, plausibly, by diffusion of charge from a bead with a higher charge to a bead with a lower charge of the same polarity)