Exploring the potential and safety of quantum dots in allergy diagnostics

Abstract

Biomedical investigations in nanotherapeutics and nanomedicine have recently intensified in pursuit of new therapies with improved efficacy. Quantum dots (QDs) are promising nanomaterials that possess a wide array of advantageous properties, including electronic properties, optical properties, and engineered biocompatibility under physiological conditions. Due to these characteristics, QDs are mainly used for biomedical labeling and theranostic (therapeutic-diagnostic) agents. QDs can be functionalized with ligands to facilitate their interaction with the immune system, specific IgE, and effector cell receptors. However, undesirable side effects such as hypersensitivity and toxicity may occur, requiring further assessment. This review systematically summarizes the potential uses of QDs in the allergy field. An overview of the definition and development of QDs is provided, along with the applications of QDs in allergy studies, including the detection of allergen-specific IgE (sIgE), food allergens, and sIgE in cellular tests. The potential treatment of allergies with QDs is also described, highlighting the toxicity and biocompatibility of these nanodevices. Finally, we discuss the current findings on the immunotoxicity of QDs. Several favorable points regarding the use of QDs for allergy diagnosis and treatment are noted.

Keywords: Biosensors; Chemistry; Nanosensors.

Fig. 1. Pathogenesis of allergies and asthma: immune response mechanisms.

Allergic reactions can be triggered by imbalances between pro-inflammatory Th2 cells and anti-inflammatory Th1 cells, resulting in an overactive immune response. B cells produce IgE antibodies that recognize and bind to allergens (e.g., drugs, foods), activating basophils, eosinophils, and mast cells. These cells release inflammatory mediators, such as histamine and leukotrienes, that cause symptoms such as itching, swelling, and difficulty breathing. The combination of these immune responses can lead to the development of asthma, a chronic respiratory condition characterized by airway inflammation and narrowing

Fig. 2. Top trending applications of QDs in biomedicine.

The figure illustrates the multifaceted utility of quantum dots (QDs) in the field of biomedicine, showcasing several demonstrated applications in theranostic sciences. QDs have emerged as versatile tools with significant implications for drug delivery, biosensing, cancer immunotherapy, and gene therapy. These nanoparticles, with their unique properties, enable precise tracking and delivery of therapeutic agents, facilitate sensitive biosensing, and hold promise for innovative approaches in cancer immunotherapy and gene-based interventions

Fig. 3. The 3-D chemical structure of representative examples of group II–VI and III–V semiconductors with higher atomic masses that can act as QDs.

The SEM micrographs show the morphologies of GaN, CdSe, and CdTe. ZnS quantum dots are mainly available in the blend phase (a) and the wurtzite (b) phase

Fig. 4. Functionalization of QD surfaces with diverse molecules.

The surface can be decorated with a wide range of molecules, such as hydrophilic, hydrophobic, and amphiphilic molecules (typical coating molecules are displayed), which can then be further connected to drugs, proteins, antibodies, and other compounds

Fig. 5. The disturbance in the immune response caused by a QD.

APCs and QDs can interact, reflecting the QDs’ effects on the innate immune system by detecting surface markers and cytokines. QDs interfere with the maturation of DCs by regulating their differentiation into activator DCs or tolerogenic DCs. Furthermore, subgroups of T cells and cytokines may be detected because of the immune response induced by QDs. The image was illustrated using BioRender.com. TLR Toll-like receptor, QD quantum dot, TNFα tumor necrosis factor, TCR T-cell receptor, MHC major histocompatibility complex, TGFβ transforming growth factor β