Superior Properties and Biomedical Applications of Microorganism-Derived Fluorescent Quantum Dots

Abstract

Quantum dots (QDs) are fluorescent nanocrystals with superb photo-physical properties. Applications of QDs have been exponentially increased during the past decade. They can be employed in several disciplines, including biological, optical, biomedical, engineering, and energy applications. This review highlights the structural composition and distinctive features of QDs, such as resistance to photo-bleaching, wide range of excitations, and size-dependent light emission features. Physical and chemical preparation of QDs have prominent downsides, including high costs, regeneration of hazardous byproducts, and use of external noxious chemicals for capping and stabilization purposes. To eliminate the demerits of these methods, an emphasis on the latest progress of microbial synthesis of QDs by bacteria, yeast, and fungi is introduced. Some of the biomedical applications of QDs are overviewed as well, such as tumor and microRNA detection, drug delivery, photodynamic therapy, and microbial labeling. Challenges facing the microbial fabrication of QDs are discussed with the future prospects to fully maximize the yield of QDs by elucidating the key enzymes intermediating the nucleation and growth of QDs. Exploration of the distribution and mode of action of QDs is required to promote their biomedical applications.

Biogenic Sulfur-Based Chalcogenide Nanocrystals: Methods of Fabrication, Mechanistic Aspects, and Bio-Applications

“…First, the NP recovery through cell lysis is commonly carried out; this destroying procedure prevents the use of the cells for another NP production cycle. The recovered NPs are then purified using several techniques, such as centrifugation, freeze-thawing, and ion exchange columns [15].…”

“…Specifically, metal ions interact with the sulfide groups of peptides to form coated metal-sulfide crystals [105,[108][109][110]. Additionally, the above-mentioned microbes should be further explored due to their easy cultivation at ambient temperature, atmospheric pressure, mild pH, and relatively fast growth that may last from a few hours to a few days [15].…”

“…Among the biogenic S-NPs described here, QDs constitute the predominant class used for specific bio-applications. Besides being applied in optoelectronic devices, sensing, and photocatalysis [223][224][225][226][227], these NPs are gaining interest in the biomedical field [15,29,38].…”

“…To be applied in the biomedical field, NPs must fulfill some strict requirements [15,218]. Water solubility, or hydrophilicity, is essential since these materials will evolve and interact within aqueous systems in the body (animal or human) and disperse to target tissues.…”

Antifungal Nano-Therapy in Veterinary Medicine: Current Status and Future Prospects

“…However, the conjugation of QDs with biological materials (AS enzymes, antibodies and DNA) caused markers imaged by a fluorescence signal [131,132]. In addition, QDs are more photostable than traditional chemical dyes which makes them to be appropriate for use in bioimaging [133,134].…”