Electrochemical (Bio)sensing of Clinical Markers Using Quantum Dots

Abstract

Quantum dots (QDs) are a kind of semiconductor nanoparticles with great potential in (bio)sensing for medical diagnosis due not only to their optical properties but also to their applicability in the development of electrochemical (bio)sensors. In this article, the use of metallic and graphene QDs for electrochemical signal amplification, either as signal tags or as electrode surface modifiers to detect clinical markers is reviewed and critically discussed. The advantages and disadvantages arising from the use of these nanoparticles in this context will be outlined together with the still required work to fulfil the characteristics needed to attain suitable electrochemical (bio)sensors with real application in clinical field.

Carbon Dots and Graphene Quantum Dots in Electrochemical Biosensing

“…These nanoparticles (NPs) can be obtained as single-layer, double-layer, and multi-layer materials, and they possess interesting properties to be used in the development of electrochemical biosensors, such as robust chemical inertness, excellent photostability, high biocompatibility, and low toxicity [7].…”

“…GQDs are recognized as good electron transporters and acceptors and show peroxidase-like properties [44,45,46,47,48], exhibiting electrochemical catalytic properties toward H 2 O 2 decomposition and allowing its sensitive detection [25,27,45], even in living cells after covalent assembly on Au [6,24]. Moreover, GQDs may in the future replace graphene, GO, or rGO as an immobilized template given that GQDs can overcome some of the disadvantages associated to the non-conducting nature of graphene oxide, and the lack of functional groups for biomolecule attachment in pure graphene [7,9,40]. It is important to remark that functionalization requires the creation of –COOH or –NH 2 groups on the graphene forms to support biomolecules’ attachment, but it may also affect their electrochemical properties [40].…”

“…Since the geometric surface area is a very important parameter in electrochemistry, modification of different substrates with GQDs can increase the rate of electrochemical reaction [6]. GQDs usually contain functional groups, such as carboxyl, hydroxyl, carbonyl, or epoxide, at their edges and basal plane that can act as reaction sites [7]. Regarding CDs, they are quasi-spherical nanoparticles less than 10 nm in diameter that exhibit good solubility in various solvents, desirable biocompatibility, and nontoxicity.…”

Red Light-Emitting Diodes with All-Inorganic CsPbI3/TOPO Composite Nanowires Color Conversion Films

“…Numerous types of quantum dots (QDs), including CdSe QDs [1], carbon QDs [2], InP QDs [3], CuInS 2 QDs [4], CdTe QDs [5], and perovskite QDs [6,7], were widely studied to be involved in the main mechanism that underlies the observed phenomenon. QDs have been utilized in the field of light-emitting diodes (LEDs) [8,9], solar cells [10,11], photodetectors [12,13], and biomarkers [14,15] and have been adopted to construct sensors to detect biologically interesting molecules [16]. In particular, a perovskite material was the most popular potential materials in recent years, and enormous progress and applications have been made in this direction [17][18][19][20][21][22][23].…”

Electrochemical Detection and Characterization of Nanoparticles with Printed Devices

“…The literature available for printed electrodes at that time was scarce, so most of the references dealt with conventional electrodes and a wider range of techniques. More recent reviews discussing electrochemical detection of some types of nanoparticles are available, but authors focused mainly on the application such as biosensing strategies or multiplexing analysis [39,43,44,45,46]. It is also worth to mention a general review on several analytical techniques for the detection and characterization of nanoparticles [9].…”