石墨烯量子点的制备及其生物应用

doi:10.15541/jim20150424

摘要/Abstract

摘要：

石墨烯量子点(GQDs)作为石墨烯材料的衍生物, 在兼顾了石墨烯优良特性的同时, 又依靠量子限域效应和边界效应而具备了光致发光(PL)等石墨烯所不具备的性质, 而且在细胞毒性、生物相容性等方面也有更好的表现。近年来, GQDs的制备方法日趋多样化, 通常将其分为Top-down和Bottom-up两种方法。随着GQDs在生物医学领域应用的不断深化, 对其形貌和尺寸控制也提出了更高的要求, 因此本文对Bottom-up法等一些有希望精确控制GQDs形貌和尺寸的方法进行了重点介绍, 并对各种方法的优缺点进行了对比。目前GQDs的生物应用主要包括生物成像、生物传感器、药物输运和抗菌剂等, 本文对其各种应用分别进行了介绍, 并结合各种应用对GQDs的要求给出了制备方法的建议。文章最后还指出了GQDs研究中存在的问题及发展方向。

关键词: 石墨烯量子点, 形貌尺寸控制, 制备方法, 生物应用, 综述

Abstract:

As the derivatives of graphene, graphene quantum dots (GQDs) have the excellent properties of graphene, and photoluminescence (PL) properties that ordinary graphene does not possess, which is attributed to quantum confinement effect and boundary effect. Moreover, GQDs perform well in terms of cytotoxicity and biocompatibility. Recently, the synthetic method of GQDs is increasingly diverse, which is usually divided into two main groups: top-down and bottom-up. With increasing application of GQDs in biomedical field, higher requirements on their morphology and size control are put forward. In this paper, we focus on the synthetic methods that are promising to control morphology and size of GQDs. Advantages and disadvantages of these methods are listed and analyzed comparatively. The biological applications of GQDs, including biological imaging, biological sensors, drug delivery and antibacterial agents, etc. are introduced. Suggestions on the choice of synthetic method for preparation of GQDs are given based on the requirements of diverse applications. The remained problems and the development directions in the research of GQDs are put forward.

Key words: graphene quantum dots, morphology and size control, synthetic methods, biological applications, review

中图分类号:

O613

孙晓丹, 刘中群, 颜昊. 石墨烯量子点的制备及其生物应用[J]. 无机材料学报, 2016, 31(4): 337-344.

SUN Xiao-Dan, LIU Zhong-Qun, YAN Hao. Preparation and Biological Application of Graphene Quantum Dots[J]. Journal of Inorganic Materials, 2016, 31(4): 337-344.

图/表 7

图1 水热法切割产生GQDs的机理示意图[11]

Fig. 1 Mechanism for the hydrothermal cutting of oxidized GSs into GQDs: a mixed epoxy chain composed of epoxy and carbonyl pair groups (left) is converted into a complete cut (right) under the hydrothermal treatment[11]

图2 绿色荧光GQDs和蓝色荧光GQDs制备流程图[15]

Fig. 2 Schematic representation of the preparation route for gGQDs and bGQDs[15]

图3 电化学方法制备GQDs溶液反应示意图[18]

Fig. 3 Schematic illustration of the generation process of GQDs solution[18]

图4 柠檬酸碳化形成GQDs和GO的示意图[26]

Fig. 4 Diagram for the synthesis of GQDs and GO[26] The black dots in the GO represent oxygen atoms

图5 C60开笼法制备GQDs示意图[23]

Fig. 5 Preparation mechanisms of GQDs using C60[23] (a) C60 molecules adsorb on the terrace, and these decompose to produce carbon clusters. (b) Temperature-dependent growth of GQDs with different equilibrium shape from the aggregation of the surface diffused carbon clusters. (c, d) Corresponding STM images for the well-dispersed triangular and hexagonal equilibrium shaped GQDs produced from C60-derived carbon clusters

表1 各方法优缺点比较

Table 1 Advantages and disadvantages of the methods for preparation of GQDs

Methods		Advantages	Disadvantages	Ref
Top-down	Hydrothermal synthesis; solvothermal synthesis; acidic oxidation; electrochemical exfoliation	Large output; simple operation.	Irregularly size and shape; lots of oxygen-containing functional groups left on the GQDs surface; strong reductants are needed; numerous defects.	[11-19]
	Oxidation cutting of CF	Simple operation; large output; relatively cheap raw materials.	Too many oxygen-containing functional groups; low quantum yield(QY).	[21]
	Ultrasonic exfoliation	Simple operation; no reduction process; fewer surface defects and more stable electronic properties.	Depending on the quality of carbon fiber; special equipments are needed.	[22]
	Electron beam lithography	Precise control on both size and shape of resultant GQDs	Complex operation; expensive equipments; extremely low output.	[23]
Bottom-up	Solution chemical approaches	Well-defined monodispersed structures; easy control of both size and shape; high purity.	Low-output; difficulty to prevent aggregation.	[21], [24-26]
	Carbonization of organic molecules	Well-defined monodispersed structures; high QY; simple operation	Low-output.	[24], [27-28]
	Cage-opening of C60	Well-defined monodispersed structures; precise control on both size and shape; high QY.	Strict reaction conditions; very high heating temperature; expensive raw materials; low-output.	[24]

图6 体内荧光成像和光动力治疗[35]

Fig. 6 In vivo imaging and PDT[35] (a) Bright-field image and (b) red-fluorescence image after subcutaneous injection of GQDs in different areas and (c) time-dependent tumour growth curves after different treatments (PDT: GQDs+light irradiation; C1: GQDs only; C2: light irradiation only)

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