A facile approach to synthesize carbon quantum dots with pH-dependent properties

Lei, Chih-Wei; Hsieh, Meng-Lin; Liu, Wei‐Ren

doi:10.1016/j.dyepig.2019.05.014

Cited by 35 publications

(20 citation statements)

References 52 publications

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“…The absorption band at 2908 cm −1 is related to the C-H stretching vibration, which is similar to the result of Saikia [62]. The peaks at 1417, 1087, and 830 cm −1 are associated with the stretching vibration of nonconjugated C=O [63], the stretching vibration of C-O [61], and the asymmetric aromatic ring skeleton vibration of C-O-C [30], respectively. The vibration frequency of the peaks at 2908, 1417, and 1087 cm −1 distributes sparsely due to the electron transition, which leads to the weaker absorption bands.…”

Section: Optical Performance Of the Prepared Pva-based Filmssupporting

confidence: 71%

Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots Fluorescent Films

Zhang

Pan

et al. 2019

Materials

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In this study, the low-cost processing residue of Radiata pine (Pinus radiata D. Don) was used as the lone carbon source for synthesis of CQDs (Carbon quantum dots) with a QY (The quantum yield of the CQDs) of 1.60%. The CQDs were obtained by the hydrothermal method, and +a PVA-based biofilm was prepared by the fluidized drying method. The effects of CQDs and CNF (cellulose nanofibers) content on the morphology, optical, mechanical, water-resistance, and wettability properties of the PVA/CQDs and PVA/CNF/CQDs films are discussed. The results revealed that, when the excitation wavelength was increased from 340 to 390 nm, the emission peak became slightly red-shifted, which was induced by the condensation between CQDs and PVA. The PVA composite films showed an increase in fluorescence intensity with the addition of the CNF and CQDs to polymers. The chemical structure of prepared films was determined by the FTIR spectroscopy, and no new chemical bonds were formed. In addition, the UV transmittance was inversely proportional to the change of CQDs content, which indicated that CQDs improved the UV barrier properties of the films. Furthermore, embedding CQDs Nano-materials and CNF into the PVA matrix improved the mechanical behavior of the Nano-composite. Tensile modulus and strength at break increased significantly with increasing the concentration of CQDs Nano-materials inside the Nano-composite, which was due to the increased in the density of crosslinking behavior. With the increase of CQDs content (>1 mL), the water absorption and surface contact angle of the prepared films decreased gradually, and the water-resistance and surface wettability of the films were improved. Therefore, PVA/CNF/CQDs bio-nanocomposite films could be used to prepare anti-counterfeiting, high-transparency, and ultraviolet-resistant composites, which have potential applications in ecological packaging materials. IntroductionPolyvinyl alcohol (PVA) is a kind of semi-crystalline polymer with a linear structure and strong hydrogen bonds intermolecular. It has been widely used in papermaking [1], textiles [2], coatings [3], adhesives [4], packaging [5], and biomedicine [6] because of its toughness [7], adhesiveness [8], biocompatibility [9], swelling behavior [10], lack of toxicity [11], and sufficient thermal stability; it is also odorless and tasteless. However, PVA is highly hydrophilic and water-soluble [12], and its light transmittance is not suitable for light-barrier packaging [13]. In order to expand the application of PVA, much attention has been paid to fabricating functional PVA composites. The existence of hydrogen-bonding groups in PVA structure and the ability to form hydrogen bonds makes PVA suitable for mixing with other materials to improve its functional properties [14,15]. In previous studies, the prepared silica in situ enhanced PVA/chitosan biodegradation films [16], PVA/tea polyphenol composite films [17], PVA reinforced with cellulose nanocrystals or cellulose nanofibers (CNF) [18], and CNF/PVA-borax hybrid foams [19] had...

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Section: Optical Performance Of the Prepared Pva-based Filmssupporting

confidence: 71%

Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots Fluorescent Films

Zhang

Pan

et al. 2019

Materials

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“…A small number of investigations have focused on the UV‐visible light absorption, reporting contradictory results: some suggested significant pH dependence on the absorption while others observing virtually no pH dependence . Our data suggest a consistent blueshift of the absorption maximum with increasing pH (Figure S8), similar to recently reported results . The calculated bandgap energy values increase, correspondingly, with increasing pH (Figure S8).…”

Section: Resultssupporting

confidence: 85%

Linear versus Branched Peptide with Same Amino Acid Sequence for Legumain‐Targeting in Macrophages: Targeting Efficiency and Bioimaging Potential

et al. 2020

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The relative legumain‐targeting efficiency of a Y‐shaped peptide and a linear peptide with the same amino acid sequence was investigated using in vitro experiments and computer simulations. Flow cytometry and fluorescence microscopy of cell types with varying levels of legumain expression (RAW 264.7, 4T1, MCF 10 A, MCF 7 and MDA MB 231) revealed that the linear peptide has a higher legumain binding efficiency in legumain‐active cells compared to the Y‐shaped peptide. Peptide‐protein docking simulations showed that the more stable linear peptide binds at the active site of legumain, whereas the Y‐shaped peptide binds at a different site. The Y‐shaped peptide has its asparaginyl binding site (‐Asn‐) coiled into an α‐helix form, and this reduces access to legumain binding. The linear peptide conjugated to fluorescent carbon dots (CDs) displayed enhanced binding efficiency towards legumain. The peptide‐CDs conjugate nanoparticles are stable under pH, temperature, and medium composition conditions similar to that may be expected in tumor environments, suggesting their high potential as a bioimaging agent.

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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: 96%

“…The parameter is almost twice lower for water, acetone, and ACN, and a very small shift of the peak maximum is noticeable. Thus, it can be concluded that the nanomaterials may be applied in various applications and media of various hydrophility, which is important in the field of diagnostics, and from this point of view is a desirable feature [17][18][19][20][21][22][23]. Our previous research showed that the bottom-up CQD synthesis routes with in situ doping enables the preparation of nanodots with the maximal QY up to 13%, which may be insufficient in some applications [44].…”

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%

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Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

et al. 2020

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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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A facile approach to synthesize carbon quantum dots with pH-dependent properties

Cited by 35 publications

References 52 publications

Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots Fluorescent Films

Preparation and Performance of Radiata-Pine-Derived Polyvinyl Alcohol/Carbon Quantum Dots Fluorescent Films

Linear versus Branched Peptide with Same Amino Acid Sequence for Legumain‐Targeting in Macrophages: Targeting Efficiency and Bioimaging Potential

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

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