Luminescent quantum dots: Synthesis, optical properties, bioimaging and toxicity

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Semiconductor nanocrystals (quantum dots) are highly investigated for their optical properties.
• Applications span optical detectors, LEDs, photovoltaics, displays, biosensing, and bioimaging.
• Various quantum dots, including metal chalcogenides and metal halides, are utilized.

Purpose of the Study:

• To review the synthesis, chemical modifications, optical properties, and bioimaging applications of semiconductor quantum dots.
• To highlight metal chalcogenide and bimetallic chalcogenide quantum dots.
• To discuss the toxicity and pharmacokinetics of quantum dot bioconjugates.

Main Methods:

• Surface modification and bioconjugation of core-only and core-shell quantum dots.
• Synthesis of various quantum dot types including metal chalcogenides, indium compounds, metal nanoparticles, nanoclusters, and carbon nanomaterials.
• Review of existing literature on quantum dot applications and properties.

Main Results:

• Nanobioconjugates form advanced imaging probes with high resolution for cellular and in vivo imaging.
• Diverse quantum dots like metal chalcogenides, indium compounds, metal NPs, nanoclusters, carbon nanomaterials, and silicon QDs are used in biosensing, bioimaging, and phototherapy.
• Heavy metal-based quantum dots are limited to in vitro use due to toxicity, while carbon and silicon quantum dots are progressing towards in vivo applications.

Conclusions:

• Semiconductor quantum dots offer significant potential in bioimaging and theranostics.
• Careful consideration of material composition is crucial to mitigate toxicity for in vivo applications.
• Further research into carbon and silicon-based quantum dots is warranted for clinical translation.