Quantum dots in biomedical applications

Wagner, Angela M.; Knipe, Jennifer M.; Orive, Gorka; Peppas, Nicholas A.

doi:10.1016/j.actbio.2019.05.022

Cited by 371 publications

(193 citation statements)

References 197 publications

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“…It can be noticed that the nanomaterial behavior is not fully uniform. Samples Dot-1-R and Dot-2-R do not exhibit any pH dependence, whereas, in the case of Dot-3-R and Dot-4-R nanodots, the PL intensity decreases at lower pH values and slight luminescence quenching is observed, which is a desirable in some cases [23][24][25][26]. One of the most interesting phenomena in the case of fluorescence dyes and nanomaterials is solvatochromism, which is an important feature in terms of biological applications [3].…”

Section: Spectroscopic Properties Studymentioning

confidence: 95%

“…Thus, it can be assumed that the right choice of the carbonizing agent enables the preparation of nanodots with desired properties using the hydrothermal method, which is known to be challenging. The average size below 10 nm suggests that quantum dots should be characterized by good fluorescence and an ability to penetrate cell membranes [24][25][26]. Figure 5 presents the optical properties of the prepared samples investigated by UV-VIS spectroscopy.…”

Section: Morphology Studymentioning

confidence: 99%

“…The worst QY (4.9%) was for Dot-4-R. All samples were additionally investigated over their photostability after seven and 30 days. High photo-stability is a desired feature, especially in long-term visualization and biochemical process investigation applications [3,[24][25][26]. The results given in Table 2 show that all samples have excellent stability after 30 days, and the decrease in QY is barely noticeable and may be caused by an auto-passivation process or slight degradation.…”

Section: Spectroscopic Properties Studymentioning

confidence: 99%

“…A promising tool are quantum dots (QDs) which can be described as objects of the size below 10 nm with unique properties [1][2][3][4]. Since their development, they have been successfully used in optoelectronics [1], food packaging [5], metals detection [6][7][8], bioimaging [9][10][11][12][13][14], photocatalysis [15,16], sensing [17][18][19][20][21][22][23], cell labelling [24], or fluorescent inks and others [25,26]. The first-generation quantum dots are semiconductors of crystalline structure [3].…”

Section: Introductionmentioning

confidence: 99%

“…), meat, grains, nuts, or vegetable by-products, which makes them a low-cost material [30,31]. Currently, these nanomaterials are widely applied in drug delivery, gene delivery, biosensing, bioimaging, cell labelling, and many other fields, including optoelectronics, photovoltaics, and photocatalysis [24][25][26]. There are two main methods for carbon quantum dot obtainment, namely, bottom-up and top-down, which differ in terms of the carbon source [30,31].…”

mentioning

confidence: 99%

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Carbon quantum dots (CQDs) are nanoobjects of a size below 10 nm. Due to their favorable features, such as tunable luminescence, unique optical properties, water solubility, and lack of cytotoxicity, they are willingly applied in biomedicine. They can be obtained via bottom-up and top-down methods. However, to increase their quantum yield they must undergo post-processing. The aim of the following research was to obtain a new type of CQDs modified with a rhodamine b derivative to enhance their fluorescence performance without biocompability deterioration. For their preparation glucose was used as a precursor and four different carbonizing agents which affected semi-and final products luminescence properties. The ready nanomaterials were investigated over their chemical structure by FTIR and NMR, whereas morphology was investigated by the TEM method. Their optical properties were determined by UV-VIS spectroscopy. Fluorescence behavior, photo-and pH-stability, as well as solvatochromism showed their applicability in various biomedical applications due to the controlled properties. The samples exhibited excellent antioxidant activity and lack of cytotoxicity on L929 mouse fibroblasts. The results showed that proposed strategy enables preparation of the superior nanomaterials with outstanding luminescence properties such as quantum yield up to 17% which can be successfully applied in cell labelling, bioimaging, and theranostics.Molecules 2020, 25, 736 2 of 18 can release cadmium ions leading to cell death. Importantly, it occurred that quantum dots may undergo certain modifications resulting in the change of their surface or chemical structure [27,28]. Finally, their preparation is expensive. Therefore, there was a need for a novel type of quantum dots which would be suitable for biomedical applications. In 2004, a new type of carbon-based materials was accidentally obtained during nanotube purification [29]. Until then, numerous types of carbon quantum dots (CQDs) have been obtained with various possible applications due to their very attractive properties, such as luminesce, good water solubility, high photostability, resistance to photobleaching or photoblinking, possibility, chemical inertness and, finally, lack of toxicity and biocompability [1][2][3]. Furthermore, CQDs' region of photoluminescence is very broad, starting in the ultraviolet and ending in the near-infrared. Although, until now, the luminescence behavior of carbon nanodots is still not fully clear, it is believed that crucial role plays two factors, namely, that the quantum size is below 10 nm and surface defects which may act as excitation energy traps. Interestingly, CQDs can successfully act as both electron donors and acceptors [2][3][4].CQDs can be prepared from various resources, such as peels (mango, orange, banana, pineapple, onion, seaweed etc.), meat, grains, nuts, or vegetable by-products, which makes them a low-cost material [30,31]. Currently, these nanomaterials are widely applied in drug delivery, gene delivery, biosensing, bioimag...

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