Tuning Ternary Zn1–xCdxTe Quantum Dot Composition: Engineering Electronic States for Light-Activated Superoxide Generation as a Therapeutic against Multidrug-Resistant Bacteria

Photoactivated antibiotics to treat intracellular infection of bacteria

Antibiotic resistance combined with pathogen internalization leads to debilitating infections. Here we test novel superoxide producing, stimuli-activated quantum dots (QDs), to treat an intracellular infection of Salmonella enterica serovar Typhimurium in an osteoblast precursor cell line. These QDs are precisely tuned to reduce dissolved oxygen to superoxide and kill bacteria upon stimulation (e.g., light). We show QDs provide tunable clearance at various multiplicities of infection and limited host cell toxicity by modulating their concentration and stimuli intensity, proving the efficacy of superoxide producing QDs for intracellular infection treatment and establishing a framework for further testing in different infection models.

68Ga CdTe/CdS fluorescent quantum dots for detection of tumors: investigation on the effect of nanoparticle size on stability and in vivo pharmacokinetics

Background

Quantum dots (QDs)-based theranostics offer exciting new approaches to diagnose and therapy of cancer. To take advantage of the unique properties of these fluorescent QDs for different biomedical applications, their structures, size and/or surface chemistry need to be optimized, allowing their stability and functionalities to be tailored for different biomedical applications.

Methodology

Cadmium telluride/Cadmium sulfide QDs (CdTe/CdS QDs) were synthesized and their structure, size, photostability and functionalities as a bioprobe for detection of Fibrosarcoma tumors were studied and compared with Cadmium telluride (CdTe) QDs. Hence, CdTe/CdS QDs were labeled with 68Ga radionuclide for fast in vivo biological nuclear imaging. Using gamma paper chromatography (γ-PC), the physicochemical properties of the prepared labeled QDs were assessed. In vivo biodistribution and positron emission tomography (PET) imaging of the 68Ga@ CdTe/CdS QDs nanocrystals were investigated in Sprague Dawley® rats bearing Fibrosarcoma tumor.

Results

CdS shell on the surface of CdTe core increases the size and photostability against high energy radiations; therefore, CdTe/CdS QDs show prolonged fluorescence as compared to CdTe QDs.

Conclusion

Excellent accumulation in tumor was observed for core/shell quantum dots, but this study showed that small changes in the size of the QDs (+1 nm), after adding the CdS shell around CdTe core, greatly change their biodistribution (especially the liver uptake).