Colloidal Gold

Colloidal gold is a colloidal suspension of gold nanoparticles in a fluid, typically water. Due to their physical, optical, electronic, and chemical characteristics, colloidal gold nanoparticles of different sizes and shapes can be used in various areas such as diagnostics, biomedicine, material technology, environmental technology, electronics, energy, and forensic science. In the healthcare and medical diagnostic sector alone, colloidal gold has many promising applications in genomics, biosensors, immunoassays, bio imaging, and various detection systems. Historically, colloidal gold has a centuries-long history of use.

As one of the first metals discovered, gold has a long history of use. The first data on colloidal gold can be found in the works of Chinese, Arab and Indian scientists who obtained colloidal gold in the V-IV centuries BC. Colloidal gold, which has many different uses, has also been used for medical purposes. For alchemists in the Middle Ages, colloidal gold was a material of interest and research. Historically, colloidal gold has been used to treat several mental illnesses, including syphilis, leprosy, plague, epilepsy, and diarrhea. The only surviving book on colloidal gold was published in 1618 by the philosopher and medical doctor Francisco Antonii. The book contains advice on extracting colloidal gold and its use in medicine. The centuries-long use of gold nanoparticles in biological studies was realized when British researchers Faulk and Taylor described a method of antibody conjugation with colloidal gold for direct electron microscopy imaging of salmonella surface antigens. This use has gone down in history as the immunochemistry revolution.

Colloidal gold is also among the most widely used and favored markers for detecting antibodies and antigens in lateral flow assays and electron microscopy. On the one hand, its spherical shape and uniformity in size and density make colloidal gold easily detectable with electron microscopy. On the other hand, lateral flow testing that combines antigen-antibody immune response with colloidal gold labeling technology offers a simple, convenient, and affordable method that allows for the qualitative or qualitative detection of antigens and antibodies in no more than 5 to 10 minutes. As mentioned before, colloidal gold is labeled in lateral flow tests. If the sample used in the test contains the compound to be tested or immunologically close analogs as it passes through the absorbent portion, a reaction with specific antibodies labeled with colloidal gold occurs with the formation of an antigen-antibody complex. The colloidal preparation participates in a competitive binding response with the antigen immobilized in the test region. If the concentration of the desired compound in the sample is higher than the threshold level, the stained band corresponding to complex formation is not observed. If it is lower, the antigen immobilized in the test region of the strip reacts with antibodies on the colloidal gold surface and forms the marker band.

Although labeling is possible through different metals, the unique molecular-recognition properties and biocompatibility of colloidal gold offer significant advantages over other conventional markers; first, its particular physical and chemical properties enable the attachment of multiple protein molecules to a single particle of colloidal gold. Moreover, its superior biocompatibility allows conjugate gold to label various traditional biological probes, including antibodies, lectins, superantigens, glycans, nucleic acids, and receptors.

Colloidal gold is a highly versatile, convenient, and reliable material for producing and developing efficient diagnostic and therapeutic tools. We have high-quality colloidal gold nanoparticles of various sizes, dispersion, and shapes to meet the diverse needs of our customers. In addition, our well-developed quality control system guarantees uniformity and safety of use to ensure the production of assays with industry-leading levels of consistency and accuracy. With adequate shelf life, our products also prevent wastage and delays in manufacturing.

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Colloidal Gold

Colloidal gold is also among the most widely used and favored markers for detecting antibodies and antigens in lateral flow assays and electron microscopy.

Conjugation Kits

A reporting system is needed to detect or measure the presence of a biological marker. For example, the first virologic tests allowed viral antigens to bind to visible targets such as erythrocytes.

Uncut Sheet

Lateral flow tests are paper-based rapid diagnostic tests for qualitatively detecting the presence, absence, or concentration of analytes of interest in specimens.