NIR-II emissive cadmium-free quantum dots for deep-tissue bioimaging and theranostic applications
Year: 2026
Type: article
Abstract: Deep-tissue fluorescence imaging remains a major challenge in cancer diagnostics due to limited tissue penetration, low signal stability, and toxicity concerns associated with conventional fluorophores and cadmium-based quantum dots. Recently, cadmium-free quantum dots exhibiting near-infrared II (NIR-II) emission have emerged as promising nanoprobes for bioimaging and theranostic applications because of their improved biocompatibility, reduced autofluorescence, enhanced photostability, and superior tissue penetration. This review summarizes recent advances in NIR-II emissive cadmium-free quantum dots, including indium phosphide, copper indium sulphide, silver indium sulphide, carbon quantum dots, and hybrid nanostructures. Particular emphasis is placed on synthesis approaches, defect-state engineering, shell passivation, and surface functionalization strategies that improve photoluminescence efficiency and imaging performance. The review further discusses fluorescence imaging, biosensing, multimodal imaging, and image-guided therapeutic applications of these nanomaterials. Biodistribution behavior, toxicity profiles, clearance pathways, and translational challenges are also critically analyzed to evaluate their clinical potential. In addition, emerging developments involving biodegradable quantum dots, NIR-II fluorescence-guided surgery, and multifunctional theranostic systems are highlighted. This review presents a mechanism-oriented and comparative framework linking material engineering, NIR-II optical properties, and biomedical performance of cadmium-free quantum dots for next-generation precision nanomedicine.
Source: Next Bioengineering
Authors: R. Ranjith, G. Roy Richi Renold, B. Suresh
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,250
OpenAlex ID: W7213644395