Everything about Microspheres
RSS feed
 
  • Fluorescent Microspheres Used for Experiments in Plant Canopies

    Fluorescent Microspheres - Polymer Spheres - 1g/cc

    Fluorescent Microspheres – Polymer Spheres – 1g/cc

    The University of Utah in collaboration with USDA Labs in Corvallis, OR performed five field campaigns in commercial vineyards in Oregon’s Willamette Valley.  Among the methodologies developed over the five-years experiment was the use of fluorescent microsheres as a fungal spore analog.  The microspheres used were inert fluorescing polyethylene micropsheres in four separate colors manufactured by Cospheric.

    The article attached below outlines the technology developed as well as microspheres sampling and meteorological equipment used in the experiments.  The authors of the article conclude that “these techniques have enabled for incredibly detailed research into particle plume dynamics in a vineyard.”

    NMiller_Poster_Methods

     

     

  • Microspheres Used as a Drug Delivery System

    There has been numerous studies done and articles published in scientific publications about the advantages of microspheres as a drug delivery system vs conventional approach to drug delivery.  Design, Development and Future Application of Microspheres by Divya Rawat , U.K> Singh and Faizi Muzaffar,  Kharvel Subharti College of Pharmacy, published in PharmaTutor discusses the types of microspheres that posses the properties needed for various drug delivery systems, their advantages and limitations.  The micropsheres best suitable to be used in biomedical applications, research and lab experiments are polystyrene.  According to the article: “Polystyrene microspheres are typically used in biomedical applications due to their ability to facilitate procedures such as cell sorting and immune precipitation. Proteins and ligands adsorb onto polystyrene readily and permanently, which makes polystyrene microspheres suitable for medical research and biological laboratory experiments. Polyethylene microspheres are commonly used as permanent or temporary filler. Lower melting temperature enables polyethylene microspheres to create porous structures in ceramics and other materials. High sphericity of polyethylene microspheres, as well as availability of colored and fluorescent microspheres, makes them highly desirable for flow visualization and fluid flow analysis, microscopy techniques, health sciences, process troubleshooting and numerous research applications.”

    Another research paper that discusses advantages and disadvantages of microspheres use for drug delivery, as well as techniques to prepare microsheres and principle behind drug delivery system is Microspheres as Drug Carriers for Controlled Drug Delivery: a Review by Nisha Sharma, Neha Purwar and Prakash Chandra Gupta, University Institute of Pharmacy, C.S.J.M. University, Kanpur, India published in International Journal of Pharmaceutical Sciences and Research.  Polymer microspheres were used for the experiment. The authors conclude that “microspheres are better choice of drug delivery system than many other types of drug delivery system. In future by combining various other strategies, microspheres will find the central and significant place in novel drug delivery, particularly in diseased cell sorting, diagnostics, gene & genetic materials, safe, targeted, specific and effective in-vitro delivery and supplements as miniature version of diseased organ and tissues in the body.”

  • Particle Image Velocimetry and Tracer Particle Visibility

    Particle Image Velocimetry (PIV) expresses a vast field with varying techniques and data acquisition methods. However, the main goal is providing an optical method of flow visualization. The exact information obtained depends on which method is used, with new algorithms and approaches being discovered constantly.

    There are generally two ways data is obtained PIV and Particle Tracking Velocimetry (PTV) which can then be broken down into many other methods based on how exactly the data was obtained and the processing done to said data. PIV measures the velocity field of a fluid based on a Eulerian method where stated locations are observed over time to determine the flow. While PTV tracks the movement of singular particles over time, a Lagrangian approach. This provides a plot of the particles movement and by relation information about the fluid flow. They each use the same tracer particles however they look at them in different senses. If logs in a river are representations of our seed particles then PIV looks at the river and sees the logs moving through it determining how the river flows based on this information. While PTV watches the movement of individual logs to obtain similar information. Which leads to the assumption that tracking particles must be easily visualized.

    Visibility being an important aspect of tracer particles is a given but how those particles are visible is where differences can come about. Tracers can be visible if they block light from reaching the visualization mechanism (eye, camera, etc.) essentially being visible as a shadow. This method is known as backlit shadowgraphy where the flow is placed between an illumination source and a camera allowing for the absence of light (shadow) caused by tracer particles to be tracked.

    Reflective Silver Coated Hollow Glass

    Another approach to assuring particle visibility is using highly reflective spheres that will reflect in the direction of your camera set-up allowing them to appear as dots of high intensity light, of the illumination source used. Lasers are most commonly used as the illumination source for this form of particle visibility. As lasers have high power, high collimation, and a relatively tight emission bandwidth. Recently LED’s are also being used as the illumination source for reflectivity visualization methods as well as backlit shadowgraphy. LED’s may not currently have the power or collimation abilities of lasers but are consistently growing in power. LED’s also have a very limited emission spectrum as well as their ease of use and low cost compared to lasers.

    Fluorescent Tracer Particles

    Finally, some tracer particles can emit their own light which allows them to be an easily distinguishable wavelength from the illumination source which can often flood the visualization area. One of the most common examples of this would be fluorescent spheres. Which when excited by the illumination source will emit a different wavelength of light. This allows the wavelength of light used as your illumination source to be filtered out providing an image with just the light from tracers. Phosphorescent spheres fall into a category similar to fluorescent particles as phosphorescence emits light similarly to fluorescence. However, phosphorescence emits over longer periods of time. Another significant difference of phosphorescent materials is their unique temperature variance which allows for them to be used as a form of temperature sensor.

    With both PIV and PTV having their strengths and weaknesses there is no clear superior method. However, with advances in technology PTV is becoming more feasible and thus may overtake PIV methods due to its ability to provide greater data varieties. Visibility options also have their unique aspects that ensure their necessity in specific cases. Shadowgraphy is gaining traction in areas due to its reduced cost requirement and ease of use. While, fluorescent tracers remain as an ideal option for applications where shadowgraphy can not quite meet the necessary criteria.

  • Fluorescent Glass Microspheres

    Fluorescent Red Coated Soda Lime Glass MicrospheresSolid glass microspheres hemispherically coated with fluorescent coatings,  a fluorescent coating is precisely applied to half of the core sphere,  making the glass spheres appear colorful and fluorescent at daylight and exhibit bright fluorescent response under UV light.  Fluorescent coatings are available in seven standard colors, with three options for glass cores available for customers who require a fluorescent tracer of a specific emission spectra and density.  Fluorescent coatings can also be applied to other microsphere cores on special request, exact size range options vary by material.  For PIV applications that typically use green lasers (530nm) as excitation sources, we recommend utilizing our fluorescent red coating in conjunction with a 570-580nm high pass filter so only the fluorescent particles will be visible during imaging.

    Three standard core densities are:

    Borosilicate Glass Core – Density ~2.2g/cc
    Soda Lime Glass Core – Density ~2.5g/cc
    Barium Titanate Glass Core – Density ~4.5g/cc

    Seven standard fluorescent color coating options on glass with broad spectrum responses:

    Fluorescent Blue Glass (445nm peak emission) at 407nm excitation
    Fluorescent Green Glass (515nm peak emission) at 414nm excitation
    Fluorescent Yellow Glass (525nm peak emission) at 485nm excitation
    Fluorescent Orange-Yellow Glass (594nm peak emission) at 460nm excitation
    Fluorescent Orange Glass (606nm peak emission) at 577nm excitation
    Fluorescent Red Glass (607nm peak emission) at 585nm excitation
    Fluorescent Violet Glass (636nm peak emission) at 584nm excitation

  • Janus (Micro) Particles – From 45um to 1mm+

    Black and White Jansum particles (1mm diameter)Cospheric offers unique capability to manufacture Janus microspheres and micro-particles with partial coatings and dual functionality. Currently half-shell or hemispherical coatings can be applied to any sphere (glass, polymer, ceramic) in sizes 45micron in diameter on up to 1mm and higher. Hemispherical coatings of less than 1 micron with tolerances as low as 0.25 micron have been routinely demonstrated. Color combinations are truly unlimited. White, black, silver, blue, green, red, yellow, brown, purple in both fluorescent and non-fluorescent have been made. Sphericity of greater than 90% and custom particle size ranges are offered.

    Fluorescent Red on Silver Coated Glass 50um

    Fluorescent Red on Silver Coated Glass 50um

    The custom coating capability offers customers the ability to create fluorescent glass micro-spheres of the specific size and emission/excitation needed. As the micro spheres and coating are solvent resistant

    they work ideally as fluorescent tracers or highly visible targets. We can overcoat clear glass or silver coated glass for the effect needed.

    For those needing very large Spheres Cospheric can coat spheres of 1mm and larger.

    Janus microparticles are now available as either dry powder or in a diellectric oil.