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How do semiconductor nanoparticles create different colour labels in medical bioassays?

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The powers of 10 — nanotechnology Examples from biological and mechanical realms illustrate various “orders of magnitude” (powers of 10), from 10⁻² meter down to 10⁻⁷ meter.

In medical bioassays, semiconductor nanoparticles—often referred to as quantum dots—create different colour labels because they emit light at specific wavelengths that are determined by the size of the individual particles.12

By utilizing these size-dependent optical properties, researchers can tag different-size particles to specific biological receptors. This allows for a wider variety of distinct colour labels than can be achieved using traditional fluorescent dye molecules. Furthermore, these nanoparticles offer improved performance over dyes, as they avoid the degradation in fluorescence that typically occurs with repeated excitation.2

In more advanced applications, these particles can be encapsulated in latex beads, allowing their resulting wavelengths to be read similarly to a barcode. This method potentially enables an enormous number of distinct labels for complex bioassays, facilitating more precise diagnostic analysis.2