Everything about microspheres and research utilizing precision spherical particles.
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Cospheric Microspheres Experts
The articles on this site are written by microsphere experts from Cospheric LLC – the leading global supplier and manufacturer of precision spherical particles.
When presenting information we look at a wide variety of sources, putting a big emphasis on any peer-reviewed technical articles that are getting published in reputable journals. Our goal is to present you with a well-rounded and informed view on the microsphere market, technologies, and applications.
As always, our technical support staff is available via email to answer any questions, offer product recommendations, provide quotes, or address custom manufacturing inquiries. We have over 2000 microsphere products in stock. If you are not finding what you are looking for on Cospheric website, let us know! We most likely will be able to recommend an alternative product to meet your needs.
Microspheres are well known in the coatings industry for their use as low-surface-area fillers that offer benefits in viscosity and density control, solids content, application and flow characteristics.
Cospheric LLC, a Santa Barbara-based microtechnology company, recently launched a line of opaque polyethylene microspheres that act as a superior opacifying agent and provide maximum hiding power with just one monolayer of microspheres as small as 40 microns in diameter. Microspheres are manufactured in any color imaginable and even in combinations of two differently colored hemispheres.
Spray drying has been used in the production of fine powders from emulsions for many years, but it is not a process in which most people associate the production of microspheres.? This journal article shows how the authors were able to produce highly spherical microspheres in the 2-10um range by controlling the levels of Chitosan and crosslinking agents used.
The key items I found of interest in this article were:
The quality of the microspheres that were produced, as seen the the attached SEM micrograph.
How the process variables did not affect the zeta potential of the microspheres produced (Table 4 below), and how the size can be varied by varying the concentrations of Chitosan or the Molecular weight (MW).
Fluorescent microspheres are round spherical particles that emit bright colors when illuminated by UV light. Ability to emit intense color under UV (black light) illumination provides contrast and visibility of microspheres relative to background materials.
During some research on PLGA microspheres we found this interesting article published in European Cells and Materials Vol 7 Suppl 2. 2004 (pages 11-12).?? They were able to achieve a significant change in the zeta potential of their microspheres just by increasing the dosage of Chitosan.?? The authors conclusions and a graph of their data follow.
Discussion and Conclusions by the authors:
The increase in zeta potential from ?70.8 mV (chitosan-free PLGA particles) to +20.5 mV with increasing chitosan concentrations in the W2-phase used for particle preparation strongly suggests that the polycationic chitosan was firmly adsorbed to the particle surface. This finding was confirmed by X-ray photoelectron spectroscopy (data not shown). The coupling of biotin via a NHS-PEGlinker showed that the amino groups of? chitosan represent suitable sites for covalent bioconjugation of different ligands. The process allows the production of particles with a mean diameter between 1 and 10 um, a useful size range for the phagocytosis by? phagocytes like dendritic cells or macrophages.
One of the microsphere topics that seems to be growing these days is biodegradability.? For those of you who are unfamiliar with the topic an excellent introductory article can be found in: Advance Drug Delivery Reviews 52 (2001) 5-16, called “Biodegradable microspheres for vitreoretinal drug delivery.”? The article does a good job describing the advantages of the various polymers available, such as poly(lactic acid) [PLA], poly(glycolic acid) [PGA], and its copolymer poly(lactic-coglycolic) acid [PLGA].
The article also recommends the prefered sterlization method for drug delivery (the authors recommend irradiation).
Exfoliating beads have a long history in cosmetics, but we are unaware of previous studies on the effect of their regular use. A clinical study with 10 subjects shows that regular exfoliation leads to a reduction in the cell turnover time of the stratum corneum (SC) by about 15% (significant at the 95% level)
There is a lot of confusion and uncertainty in the academic community as well as the industry on exactly what is a microsphere. Below is the definition of “microsphere” that we use, because it is clear and straight-forward:
Microsphere is a term used for a small solid spherical particle, with diameter in the micrometer range (typically 1 micron to 1000 micron (1mm)).
What a Microsphere is Not:
A microsphere is not the same as a microcapsule, because microcapsules typically consist of a flexible (deformable) shell encapsulating a fluid, which might be liquid or gas. Microspheres always have a solid shell. Even if the microsphere is technically hollow (containing gas inside), its shape is not significantly flexible or deformable.
A microsphere is not the same as a microparticle, because microparticle is a general term that refers only to the size of the granular material and does not provide information on the shape. Microspheres are always round and spherical. There are no sharp edges, oblong shapes, or debris.
A microsphere is not the same as a nanopshere, because nanospheres have diameters on the nanoscale (typically between 1 nanometer and 1000 nanometers (1 micron)). Nano-diameters present a complete different characteristics, behaviors, and functionalities.
Microspheres are manufactured from various natural and synthetic materials. Glass microspheres, polymer microspheres, and ceramic microspheres are commercially available. Solid and hollow microspheres vary a lot in density and, therefore, are used for different applications. Hollow microspheres are typically used as additives to lower the density of a material. Solid microspheres have numerous applications depending on what material they are constructed of and what size they are.
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