Microspheres come in many different grades and sizes and are usually solid particles that are composed of polymers, glass and ceramics. All images are courtesy of COSPHERIC
LLC Microspheres are round microparticles that typically range from 1 to 1000 microns in diameter. In the pharmaceutical industry and cosmetics, microspheres are well known for their ability to deliver active ingredients. This process usually involves the microencapsulation dun dun drug or cosmetic active ingredient to protect against the effects of the deterioration of the environment or the release and performance in the final product. The active ingredients are released by dissolution of the capsule walls, mechanical rupture (rubbing, pressure or impact), the merger or the process of digestion. Solid microspheres are widely used as fillers and spacers in a variety dindustries.
microspheres used to manufacture and test medical devices are typically solid particles that are made from durable materials and stable materials such as polymers, glass, and in some cases, ceramics. Different types and grades of microspheres are available and selected based on the specific needs of lapplication.
They are often used as tracers and challenge particles in medical devices. In these situations, it is better using separate microspheres dun sphere diameter greater than 50 microns which are brightly colored (red, blue, black, yellow or green) because they offer a contrast with the background material and visibility naked eye in daylight. Colored microspheres are commonly used in tests of filtration media and systems, evaluations and bottles containing cleaning, mechanical flow tracing and fluid processes of sedimentation and centrifugation, pharmaceutical manufacturing and contamination control.
Fluorescent microspheres are recommended for applications that require particle THE USE emit distinctive colors WHEN IT IS illuminated by UV light and offer additional sensitivity for lobservation through THE USE OF microscopes, lasers and dautres danalyse methods. Examples include microcirculation and biological research, limagerie and flow cytometry. Fluorescent microspheres can be excited and detected by a variety of methods and are useful as experimental particles for acoustical and optical analytical systems.
Other types of microspheres that are relevant for medical devices are optically opaque and opaque to X-rays, as well as charge and magnetic microspheres. Opaque microspheres are desirable for maximum contrast in optical and electronic beams. And magnetic particles are likely responsible Detre manipulated by electromagnetic fields.
monodisperse microspheres are used to undercut microscopes, léquipement light scattering and the measuring devices of other particles. They are ideal for applications in which Spacer uniform bond thickness is a necessity. Spheres standard particle size can be used to develop and test new analytical tools for the characterization of particle size materials.
The microspheres are particles which are often provided in the form of dry powder or in a solution. Higher sphericity and roundness offer spread omnidirectional and easy cleaning. Microspheres can be observed directly on the surface or in the media tested. In addition, due to their grain sized, they can be filtered, collected and recycled at the end of the test process.
Fluorescence occurs lorsquune molecule absorbs light lEnergie form again and immediately release the energy as light. The wavelength dexcitation is the wavelength characteristic which absorbs a molecule, and the wavelength is the wavelength resignation which emits characteristic molecule.
fluorescent microspheres emit bright colors and distinctive WHEN IT IS illuminated by light Wavelength shorter than the wavelength resignation. Emission of intense color contrast and improves visibility compared to reference materials. In addition to the advantages of the classic high quality microspheres such as roundness, smoothness and lethally, fluorescent spheres provide additional sensitivity and detection of analytical methods. Fluorescent microspheres can be detected with an epifluorescence microscope, confocal microscope, fluorimeter, fluorescence spectrophotometer, or activated cell sorter by fluorescence. They can also be detected contacts using a mineral or UV light.
Yellow polyethylene microspheres, measuring 355-425 microns (40x) can stand on documents information package.
fluorescent microspheres are available in a variety dexcitation Wavelength and resignation. These changes allow lengths dondes complex technical experiments in which colored microspheres represent different experimental variables or conditions and can be separated on the basis of their excitation spectra or other, or resignation. For example, using fluorescent microspheres of different diameters sphere provides an additional variable that allows controlled scientific and dingénieurs initial follow the location of the microspheres.
A unique property of fluorescent spheres is their ability to appear transparent and virtually invisible under ordinary light and emit intense color visible WHEN IT IS turned on. This effect allows blind tests and controlled experiments in which the microspheres are invisible until OPERATOR that the procedure was conducted, which eliminates any bias lincertitude operator as to the validity of lexperience. This unique feature of fluorescent microspheres has many applications in the development and testing of medical devices (eg, simulating the spread of infection and viruses, bottle and container cleaning evaluations and troubleshooting of process and control) .
The most fluorescent microspheres are internal hard dyed (natural) polymer beads using methods property dincorporer the fluorescent dye in the polymer matrix. This method produces vivid colors and fluorescent minimizes photobleaching, and prevents dyes sinfiltrer surrounding media. The spectral properties of fluorochromes are dependent on their concentration and physical environment. Lexcitation resignation and exact maxima may vary depending on the size and composition of the microspheres. There are several types of fluorescent polymer microspheres on the market that are produced from dune variety of raw materials, which makes it suitable for a variety of applications.
The density of fluorescent microspheres can be adjusted to match the specific gravity or Leau dautres desired media. Particles that are heavier than the media in which they are dispersed settle to the bottom of the container over time. Particles that are lighter than the media will float to the surface and saccumulent on the surface. Corresponding to the density of the microspheres in the solution of the base creates a stable suspension of particles, which ensures uniform distribution and prevent their settling or collect at the top of the container. This adaptation is achieved by selecting a base polymer in the vicinity of the desired density and the use of additives which are incorporated property in the polymer matrix during the manufacturing process. This process corresponds to the density of the microspheres or Leau dautres media and the desired results in particles floating neutral and an optimal suspension of particles in solution.
fluorescent microspheres are often used in fluorescence microscopy and photography, as well as research of biomedical technology and biomedical diagnostics. They are often used to lair Leau and pearl testing and diagnostic applications. Unique applications of fluorescent spheres are constantly being discovered.
Colored microspheres
microspheres used as tracers and challenge particles in medical devices need not be fluorescent. As previously stated, brightly colored microspheres can provide a contrast with the background material and visibility to the naked eye in daylight.
solid polyethylene microspheres are smooth, highly spherical particles which are insoluble in water and most solvents. It can be made in any color and nimporte withstand temperatures up to 100 ° C. These spheres can be produced with densities of 0.96 to 1.3 g / cc. Polyethylene solid microspheres incorporating pigments and additives to the polymer matrix interior to obtain colored particles which are displayed on the surface of a material or dune solution.
The advantage of THE USE solid microspheres instead of color pigments or dyes is that the microspheres are much more robust and controlled particle, and easy to handle and clean. The pigment particles are very small, difficult to disperse, and can be dangerous. In general, the pigment particle size less than 1 micron are used to increase the strength of color. However, powders of pigment particles in the submicron size range is difficult to work with because they tend to sagglomérer and, therefore, do not disperse well in solution. In addition, powders of less than 5 microns in size are considered respirable by lOccupational Safety and Health Administration, as they are small enough to penetrate into the nose, upper respiratory tract and lungs, which is dangerous to the health of workers are regularly exposed to dust. Because the microspheres are typically 5 microns or more, they are easier to handle and does not create respiratory hazards.
The microspheres are often supplied as free-flowing powder and dry to ensure a simple formulation, the application controlled and easy cleaning. Colored microspheres can be displayed to the naked eye, measured and filtered, scratched, or recycled at the end of the process. For example, if Leau rinse Examination is in progress, the microspheres can be collected on membrane filters for visual or microscopic Inspectorate.
Opaque microspheres
In general, when light strikes an interface between two substances, some of the light is reflected, absorbed and scattered, and the rest is transmitted. An opaque substance transmits little or no light and therefore reflects, scatters, or absorbs much. Lopacité microspheres can be quantified in many ways, including viewing spheres under a microscope with a backlight or measuring the reflectance spheres monolayers on white and black background.
Opaque microspheres allow light to pass through, which means that the monolayer of beads opaque not transmitting light, hiding under maximum material and color. Opaque microspheres are desirable for maximum contrast in optical and electronic beams. They are also beneficial for applications where uniform color and opacity of the color beneath is desired. Polymer microspheres can be seen as transparent and invisible LOEIL partially translucent or opaque which provides maximum hiding power.
polyethylene microspheres change fluorescent color under UV light.
In general, high levels dopacité becomes more difficult to achieve because of microscopic particles is proportional to opacity The thickness of the material. Because the chemistry of glass, it is difficult to create opaque glass spheres. More color glass microspheres were made by the fixation of the dyes on the surface of the particle and not realize dopacité significant. Ceramic microspheres microspheres can be opaque, but in a lot Nont generally the same level dopacité (some are more opaque than others). The method of manufacture of microspheres can lincorporation polyethylene dyes and opacifiers interior of the solid sphere, which guarantees that the spheres are manufactured by the same color and lopacité.
optical opacity, as described above, is defined as the degree to something which reduces the passage of light. It should not be confused with a radiopacity, which is the phenomenon of not permitting the passage of electromagnetic radiation dun, otherwise known as lopacité, X-ray or for other forms of radiation. Certain medical applications require the development dappareils radiopaque microspheres, which may be obtained by incorporating magnetic elements and metal in the structure of the microsphere. This process allows microspheres to be easily detectable by radiography and demonstrates superior contrast and reflectivity in optical, ultrasound, detection methods and lélectron beam.
monodisperse microspheres
As mentioned earlier, monodisperse microspheres have applications in microscopes, equipment for light scattering, functionalities and other measuring devices particles. Certified particle size microspheres are traceable to standard yardstick through lInstitut National Standards and Technology (NIST). This function allows laboratories to demonstrate the traceability of their methods danalyse as required by ISO 9000, ISO 10012, ANSI / NCSL Z540, GMP / GLP and other standards and regulations. Spheres standard particle size can be used to develop and test new analytical tools for the characterization of particle materials. It is very difficult to visualize 3D objects with analytical instruments. Because the instruments can usually focus on a single surface, 3-D objects often produce images of distorted shapes. Use of the spheres, which have the same dimensions lorsquils are viewed from any angle, instead of particles of irregular shape, minimizes these effects.
indictment, magnetic and metallic microspheres
to create positive or negative charges, proprietary additives are incorporated into each microsphere during the manufacturing process. This charge is permanent, it does not dissipate over time and can not be grounded. The microsphere everything is loaded and respond to electric fields. Dark colored or black or magnetic microspheres may be antistatic, and a black coating on a magnetic portion of the microsphere can be used to create functionalized hemispheres. For example, magnetic half-shells can be manipulated to turn microspheres with an electromagnetic field.
An interesting and unique feature of half-shell magnetic microspheres is their ability to sorienter in response to electromagnetic fields and show a visual response to lobservateur. This response is obtained by bipolar bicolor spheres with dipole precisely aligned with the two hemispheres of different colors. Due to the dipole, the sphere rotates in an electromagnetic field to daligner lhémisphère more positive stimuli negatively charged and vice versa. As spheres align themselves, the viewer observes the color dun hemisphere, while the other hemisphere will be hidden from view to provide a good indication of the presence of visible field. In an alternating electromagnetic field, these microspheres can run hundreds of times per second.
This functionality is achieved with a top exclusive and patented process which allows extremely precise coating on one hemisphere without affecting Lautre. Each coating is custom formulated for color, load and resistance to solvents, and magnetic properties, and surface electrical needs of the customer. Hemispherical coatings less than 1 um with tolerances as low as 0.25 um have been systematically demonstrated. The color combinations are almost endless, white, black, silver, blue, green, red, yellow, brown and purple, and transparent microspheres have been made. Sphericity greater than 90%, grain size classes are available for customization.
functionalized microspheres bicolor
(half-shell magnetic).
spheres were originally developed for very high tolerance electronic paper reflective digital screens in which functionalized microspheres were used to create an image that appears lobservateur. For a high resolution for daffichage applications, it is essential that all spheres only responds to the electromagnetic field in the same manner and at the same time and that he saligne precisely with the other spheres. It is also essential that he has not degraded ny color on the screen.
lorientation bicolor microspheres for application in medical devices requires further exploration but it is a promising area for future development. This technology could be used as a visible marker of the presence of a field in an electromagnetic medical device, as well as tracer particles or carrier handled with an electromagnetic field.
For skin based medical devices loaded microspheres can be used to develop products that are attracted or repelled by the skin. Human skin has an electrostatic charge very positive. Because like charges repel and opposite charges sattirent, the product manager can be manipulated to be more attracted to the skin if the product is designed to remain on the skin for a long time. It can also be manipulated to be less attracted to the skin if the product should remain for a short time, which makes the product easy for the user to delete.
