Quantum Dots in Biomedical Research

Fontes, Adriana; Lira, Rafael B.; Seabra, Maria Aparecida Barreto Lopes; Silva, Thiago Gomes da; Neto, Antônio Gomes de Castro; Santos, Beate S.

doi:10.5772/50214

Cited by 18 publications

(26 citation statements)

References 60 publications

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“…As a consequence of the quantum confinement, the nanocrystals will present energy level discretization and bandgap energy (Eg) inversely proportional to their size, as shown in Figure 1a. 13 Thus, the quantum confinement influences directly the QDs optical properties, providing size tunability of the emission band, exemplified by the naked-eye fluorescence of different sized CdTe QDs shown in Figure 1b. 1,2,13 The QDs emission wavelength is also inversely proportional to the value of Eg: the higher Eg the lower the emission wavelength.…”

Section: Introductionmentioning

confidence: 99%

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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Quantum dots (QDs) are semiconductor nanocrystals, which present unique photophysical properties, enabling their application as new fluorescent platforms for biomedical sciences. Colloidal QDs are end-capped with organic or inorganic compounds, not only to prevent their agglomeration but also to provide reaction sites for the attachment of targeting (bio)molecules, nanoparticles or other interfaces, for specific biological purposes. The (bio)conjugation can involve non-covalent or covalent interactions, which can be accomplished through different strategies. The final assembly needs to maintain its chemical and optical stability and biochemical functionality. Although a relative good comprehension of the experimental procedures has been established, the bioconjugation process is still a challenge. The present manuscript aims to review the main (bio)conjugation strategies successfully applied to QDs, describing the steps necessary to prepare stable targeting fluorescent nanoplatforms, as well as some usual methods used to evaluate and optimize this process.

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Section: Introductionmentioning

confidence: 99%

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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“…Most of these nanoparticles are biocompatible with proteins and antibodies, preserve a photostable emission during prolonged excitation, and show a tuneable range of excitation, a narrow emission spectrum and high fluorescence performance [30][31][32][33]; furthermore, they present a large surface area that enables the controlled conjugation of biomolecules [34]. All these characteristics are desirable for the labelling and monitoring of proteins in vitro and in vivo [35][36][37][38]. Considering their optical attributes, QD may also constitute a suitable option for imaging diagnoses of diseases [39].…”

Section: Introductionmentioning

confidence: 99%

Quantum Dot Labelling of Tepary Bean (Phaseolus acutifolius) Lectins by Microfluidics

et al. 2020

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Lectins are bioactive proteins with the ability to recognize cell membrane carbohydrates in a specific way. Diverse plant lectins have shown diagnostic and therapeutic potential against cancer, and their cytotoxicity against transformed cells is mediated through the induction of apoptosis. Previous works have determined the cytotoxic activity of a Tepary bean (Phaseolus acutifolius) lectin fraction (TBLF) and its anti-tumorigenic effect on colon cancer. In this work, lectins from the TBLF were additionally purified by ionic-exchange chromatography. Two peaks with agglutination activity were obtained: one of them was named TBL-IE2 and showed a single protein band in two-dimensional electrophoresis; this one was thus selected for coupling to quantum dot (QD) nanoparticles by microfluidics (TBL-IE2-QD). The microfluidic method led to low sample usage, and resulted in homogeneous complexes, whose visualization was achieved using multiphoton and transmission electron microscopy. The average particle size (380 nm) and the average zeta potential (−18.51 mV) were determined. The cytotoxicity of the TBL-IE2 and TBL-IE2-QD was assayed on HT-29 colon cancer cells, showing no differences between them (p ≤ 0.05), where the LC50 values were 1.0 × 10−3 and 1.7 × 10−3 mg/mL, respectively. The microfluidic technique allowed control of the coupling between the QD and the protein, substantially improving the labelling process, providing a rapid and efficient method that enabled the traceability of lectins. Future studies will focus on the potential use of the QD-labelled lectin to recognize tumor tissues.

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“…9 Thus ZnS core doped with manganese and capped with a suitable molecule QDs have paved the pathway to using biologically active materials in nanotechnology research. 10 Various routes have been investigated to synthesize small sized, homogeneous QDs but among all existing methods, aqueous synthesis of the particles involving low temperature and greener methodologies has various advantages over the conventional ones. 10 The recent advances in the synthetic chemistry of ZnS QDs involving surfactants or capping agents for controlling the growth is expected to lead to the existence of newly generated advanced nanomaterials with highly improved quality.…”

Section: Introductionmentioning

confidence: 99%

“…10 Various routes have been investigated to synthesize small sized, homogeneous QDs but among all existing methods, aqueous synthesis of the particles involving low temperature and greener methodologies has various advantages over the conventional ones. 10 The recent advances in the synthetic chemistry of ZnS QDs involving surfactants or capping agents for controlling the growth is expected to lead to the existence of newly generated advanced nanomaterials with highly improved quality. 11 Developing new capping agents that can reduce the toxic effects, improve the optical properties and also control the growth of quantum dots is a highly challenging task.…”

Section: Introductionmentioning

confidence: 99%

“…15 Also sensing of metal ions becomes difficult if thiol group is blocked upon attaching the capping agent to the core metal of the host crystal lattice. There are various capping agents that have been explored, like mercaptophenylboronic, 16 thioglycerol, L-cysteine, 10 MPA (mercaptopropionic acid), MPTS (mercapto propyl trimethoxysilane), 13 N-acetyl L-cysteine, glutathione, 17 thioglycolic acid, cysteamine, etc. QDs based bioconjugates are also developed for detection at high sensitivity.…”

Section: Introductionmentioning

confidence: 99%

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