TiO2–Graphene Quantum Dots Nanocomposites for Photocatalysis in Energy and Biomedical Applications

The focus of current research in material science has shifted from “less efficient” single-component nanomaterials to the superior-performance, next-generation, multifunctional nanocomposites. TiO2 is a widely used benchmark photocatalyst with unique physicochemical properties. However, the large bandgap and massive recombination of photogenerated charge carriers limit its overall photocatalytic efficiency. When TiO2 nanoparticles are modified with graphene quantum dots (GQDs), some significant improvements can be achieved in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron-hole (e−-h+) recombination. Accordingly, TiO2-GQDs nanocomposites exhibit promising multifunctionalities in a wide range of fields including, but not limited to, energy, biomedical aids, electronics, and flexible wearable sensors. This review presents some important aspects of TiO2-GQDs nanocomposites as photocatalysts in energy and biomedical applications. These include: (1) structural formulations and synthesis methods of TiO2-GQDs nanocomposites; (2) discourse about the mechanism behind the overall higher photoactivities of these nanocomposites; (3) various characterization techniques which can be used to judge the photocatalytic performance of these nanocomposites, and (4) the application of these nanocomposites in biomedical and energy conversion devices. Although some objectives have been achieved, new challenges still exist and hinder the widespread application of these nanocomposites. These challenges are briefly discussed in the Future Scope section of this review.

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Photoinitiated Polymerization of Hydrogels by Graphene Quantum Dots

Nanomaterials ◽

10.3390/nano11092169 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2169

Author(s):

Yuna Kim ◽

Jaekwang Song ◽

Seong Chae Park ◽

Minchul Ahn ◽

Myung Jin Park ◽

...

Keyword(s):

Quantum Dots ◽

Mechanical Strength ◽

Biomedical Applications ◽

Contact Lenses ◽

Graphene Quantum Dots ◽

Research Fields ◽

Wide Range ◽

Stimulus Responsive ◽

Dual Functions ◽

Initiation Of Polymerization

As a smart stimulus-responsive material, hydrogel has been investigated extensively in many research fields. However, its mechanical brittleness and low strength have mattered, and conventional photoinitiators used during the polymerization steps exhibit high toxicity, which limits the use of hydrogels in the field of biomedical applications. Here, we address the dual functions of graphene quantum dots (GQDs), one to trigger the synthesis of hydrogel as photoinitiators and the other to improve the mechanical strength of the as-synthesized hydrogel. GQDs embedded in the network effectively generated radicals when exposed to sunlight, leading to the initiation of polymerization, and also played a significant role in improving the mechanical strength of the crosslinked chains. Thus, we expect that the resulting hydrogel incorporated with GQDs would enable a wide range of applications that require biocompatibility as well as higher mechanical strength, including novel hydrogel contact lenses and bioscaffolds for tissue engineering.

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Recent Developments in Carbon Quantum Dots: Properties, Fabrication Techniques, and Bio-Applications

Processes ◽

10.3390/pr9020388 ◽

2021 ◽

Vol 9 (2) ◽

pp. 388

Author(s):

Rehan M. El-Shabasy ◽

Mohamed Farouk Elsadek ◽

Badreldin Mohamed Ahmed ◽

Mohamed Fawzy Farahat ◽

Khaled N. Mosleh ◽

...

Keyword(s):

Quantum Dots ◽

Green Synthesis ◽

Graphene Quantum Dots ◽

Carbon Sources ◽

Carbon Quantum Dots ◽

Synthesis Methods ◽

Wide Range ◽

Recent Developments ◽

Potential Applications ◽

Harsh Conditions

Carbon dots have gained tremendous interest attributable to their unique features. Two approaches are involved in the fabrication of quantum dots (Top-down and Bottom-up). Most of the synthesis methods are usually multistep, required harsh conditions, and costly carbon sources that may have a toxic effect, therefore green synthesis is more preferable. Herein, the current review presents the green synthesis of carbon quantum dots (CQDs) and graphene quantum dots (GQDs) that having a wide range of potential applications in bio-sensing, cellular imaging, and drug delivery. However, some drawbacks and limitations are still unclear. Other biomedical and biotechnological applications are also highlighted.

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Influence of Graphene Quantum Dots Surface Charge on their Uptake and Clearance in Melanoma Cells

Nanoscale Advances ◽

10.1039/d0na00935k ◽

2021 ◽

Author(s):

Lakshmi Narashimhan Ramana ◽

Le N.M. Dinh ◽

Vipul Agarwal

Keyword(s):

Quantum Dots ◽

Surface Charge ◽

Biomedical Applications ◽

Graphene Quantum Dots ◽

Melanoma Cells ◽

Rapid Clearance

Graphene quantum dots (GQDs) continue to draw interest in biomedical applications. However, their efficacy gets compromised due to their rapid clearance from body. On one side, rapid clearance is desired...

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Organic dots (O-dots) for theranostic applications: preparation and surface engineering

RSC Advances ◽

10.1039/d0ra08041a ◽

2021 ◽

Vol 11 (4) ◽

pp. 2253-2291

Author(s):

Amin Shiralizadeh Dezfuli ◽

Elmira Kohan ◽

Sepand Tehrani Fateh ◽

Neda Alimirzaei ◽

Hamidreza Arzaghi ◽

...

Keyword(s):

Quantum Dots ◽

Photodynamic Therapy ◽

Photothermal Therapy ◽

Biomedical Applications ◽

Surface Engineering ◽

Graphene Quantum Dots ◽

Carbon Quantum Dots ◽

Cargo Delivery ◽

Bio Imaging ◽

Theranostic Applications

Organic dots is a term used to represent materials including graphene quantum dots and carbon quantum dots because they rely on the presence of other atoms (O, H, and N) for their photoluminescence or fluorescence properties. Cargo delivery, bio-imaging, photodynamic therapy and photothermal therapy are major biomedical applications of organic dots.

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Microplasma Band Structure Engineering in Graphene Quantum Dots for Sensitive and Wide-Range pH Sensing

ACS Applied Materials & Interfaces ◽

10.1021/acsami.1c18440 ◽

2021 ◽

Author(s):

Darwin Kurniawan ◽

Bai Amutha Anjali ◽

Owen Setiawan ◽

Kostya Ken Ostrikov ◽

Yongchul G. Chung ◽

...

Keyword(s):

Quantum Dots ◽

Band Structure ◽

Graphene Quantum Dots ◽

Ph Sensing ◽

Wide Range ◽

Structure Engineering

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Ball-Milling Graphite Used for Synthesis of Biocompatible Blue Luminescent Graphene Quantum Dots

Advance Research in Textile Engineering ◽

10.26420/advrestexteng.2021.1064 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Zhou J ◽

◽

Dong Y ◽

Ma Y ◽

Zhang T ◽

...

Keyword(s):

Quantum Dots ◽

Ball Milling ◽

Graphene Quantum Dots ◽

Raw Material ◽

Hydroxyl Groups ◽

High Quality ◽

Widespread Application ◽

Force Microscopy ◽

Atomic Force ◽

Transmission Electron

Graphene Quantum Dots (GQDs) have been prepared by oxidationhydrothermal reaction, using ball-milling graphite as the starting materials. The prepared GQDs are endowed with excellent luminescence properties, with the optimum emission of 320nm. Blue photoluminescent emitted from the GQDs under ultraviolet light. The GQDs are ~3nm in width and 0.5~2 nm in thickness, revealed by high-resolution transmission electron microscopy and atomic force microscopy. In addition, Fourier transform infrared spectrum evidences the existence of carbonyl and hydroxyl groups, meaning GQDs can be dispersed in water easily and used in cellar imaging, and blue area inside L929 cells were clearly observed under the fluorescence microscope. Both low price of raw material and simple prepared method contribute to the high quality GQDs widespread application in future.

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Carbon Based Nanodots in Early Diagnosis of Cancer

Frontiers in Chemistry ◽

10.3389/fchem.2021.669169 ◽

2021 ◽

Vol 9 ◽

Author(s):

Gurpal Singh ◽

Harinder Kaur ◽

Akanksha Sharma ◽

Joga Singh ◽

Hema Kumari Alajangi ◽

...

Keyword(s):

Quantum Dots ◽

Early Stage ◽

Imaging Techniques ◽

Graphene Quantum Dots ◽

Carbon Quantum Dots ◽

Diagnostic Methods ◽

Early Diagnosis Of Cancer ◽

Successful Treatment Outcome ◽

Wide Range ◽

Carbon Based

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

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Recent Advances in the Cancer Bioimaging with Graphene Quantum Dots

Current Medicinal Chemistry ◽

10.2174/0929867324666170223154145 ◽

2018 ◽

Vol 25 (25) ◽

pp. 2876-2893 ◽

Cited By ~ 15

Author(s):

Keheng Li ◽

Xinna Zhao ◽

Gang Wei ◽

Zhiqiang Su

Keyword(s):

Quantum Dots ◽

Biomedical Applications ◽

Cell Imaging ◽

Graphene Quantum Dots ◽

Biological Properties ◽

Live Cells ◽

Physical Chemical ◽

Specific Cancer ◽

Good Biocompatibility ◽

Low Cytotoxicity

Fluorescent graphene quantum dots (GQDs) have attracted increasing interest in cancer bioimaging due to their stable photoluminescence (PL), high stability, low cytotoxicity, and good biocompatibility. In this review, we present the synthesis and chemical modification of GQDs firstly, and then introduce their unique physical, chemical, and biological properties like the absorption, PL, and cytotoxicity of GQDs. Finally and most importantly, the recent applications of GQDs in cancer bioimaging are demonstrated in detail, in which we focus on the biofunctionalization of GQDs for specific cancer cell imaging and real-time molecular imaging in live cells. We expect this work would provide valuable guides on the synthesis and modification of GQDs with adjustable properties for various biomedical applications in the future.

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