Microspheres are small spherical entities formed by dispersing or adsorbing drugs in a polymer matrix. The particle size is typically between 1 μm and 250 μm, and the largest can reach more than 800 μm. Microsphere technology is at the intersection of cutting-edge disciplines such as materials science, polymer technology, medical technology, and microelectronics. Once injected into the body, microspheres are gradually degraded in the body, allowing the drug to be released slowly at a certain rate, maintaining the drug concentration in the blood at the site of the lesion, thereby prolonging the half-life of the drug and achieving long-acting sustained release.
Fluorescent Microspheres for Nucleic Acid Detection
Microspheres encoded with up-converting luminescent materials of different colors can be used to bind different reporter labels, and when bound to single-stranded DNA, the fluorescence intensity will be different. A scientist used a similar method to wrap up-converting luminescent nanoparticles inside polystyrene microspheres, and adjusted the ratio of upconverting nanoparticles (different emission wavelengths) to obtain different fluorescence-encoded microspheres. There is no optical overlap between the upconverting luminescence-encoded microspheres and the dye-labeled reporter molecule, so there is a wide range of wavelengths from labeling dye to fluorescence. Quantum dot-encoded microspheres can also be used to bind target DNA molecules. Using the laminar flow of the microfluidic chip and an external magnetic force, the reporter molecule and the detergent generate three fluid streams through the action of the magnetic force. Using quantum dot-labeled microspheres, the signal appears to be enhanced after the hybridization chain reaction. Therefore, quantum dot-labeled microspheres can be used for multiplex detection of miRNA overexpression in human lung cancer cells.
Fluorescent Microspheres for Protein Detection
Multi-color quantum dot-bound microspheres have been widely proven to be used for the simultaneous detection of multiple antigens, including IgG, tumor markers, and pathogenic markers. Two different antigens can be detected simultaneously using upconverting nanoparticles and magnetic nanoparticle-labeled microspheres. Based on microfluidic technology, AFP (FEMMs fluorescence-encoded magnetic beads) is used to magnetically enrich and separate Fe3O4 nanoparticles (by high-temperature chemical swelling). quantum dots and Fe3O4 nanoparticles are effectively combined with microspheres through polymer chain ends or hydrophobic interactions. This technology is also widely used in the detection of multiple biomarkers.
Fluorescent Microspheres for Bacteria Detection
Traditional bacterial detection (such as microdilution or E-test) takes a long time, so it is necessary to develop a method that can detect multiple bacteria quickly and efficiently. One researcher used polystyrene microspheres to rapidly enumerate Staphylococcus aureus parasitic on human cornea and conjunctiva. Another researcher incubated fluorescent microspheres with vancomycin, combined with the ligase on the bacterial cell wall through hydrogen bonds and effectively identified live or dead bacteria in solution through the diffusion of fluorescent magnetic bead microspheres.
The microsphere material with nanopore structure has a very high specific surface area, so it has extremely strong adsorption performance. When special functional groups are attached to the surface of the microsphere, it can selectively adsorb certain substances. This feature makes the nanosphere material an indispensable material in the separation and purification process of all biological drugs and natural medicines. In addition, gas-phase and liquid chromatography are the most widely used methods for pharmaceutical analysis and detection today, and the core material of chromatography is the microsphere material.
In the field of pharmaceutical preparations, microspheres are also ideal carriers for slow and controlled release of drugs. As mentioned above, when the active ingredients are loaded into hollow or porous microsphere carriers, the drug can be released slowly in the human body to reduce the toxic side effects of the drug and increase the effectiveness of the drug. The porous microspheres composed of magnetic materials can be used as the carrier of the targeted drug delivery system. Under the action of an external magnetic field, the drug can be loaded to a predetermined area, which can make the anticancer drugs on the immunomagnetic microspheres more accessible to cancer cells and improve the effect of killing cancer cells.
As an expert in microsphere preparation, CD Formulation has a research team of pharmaceutical experts, including chemists, biochemists, engineers and highly skilled operators, and is able to provide customized fluorescent microsphere preparation services using membrane emulsification and sedimentation microsphere preparation technologies. The fluorescent microspheres readily available from CD Formulation are Green Fluorescent PLGA Microspheres of various particle sizes ranging from 1 μm, 2 μm, 5 μm, 20 μm to 25 μm, 30 μm, 40 μm, and 50 μm. These particles can be used for imaging and cell tracking in drug discovery.