Noninjection Facile Synthesis of Gram-Scale Highly Luminescent CdSe Multipod Nanocrystals

Nearly all reported approaches for synthesis of high quality CdSe nanocrystals (NCs) involved two steps of preparation of Cd or Se stock solution in advance and then mixing the two reactants via hot-injection in high temperature. In this manuscript, Gram-scale CdSe multipod NCs were facilely synthesized in a noninjection route with the use of CdO and Se powder directly as reactants in paraffin reaction medium containing small amount of oleic acid and trioctylphosphine. The influence of various experimental variables, including reaction temperature, nature and amount of surfactants, Cd-to-Se ratio, and the nature of reactants, on the morphology of the obtained CdSe NCs have been systematically investigated. After deposition of ZnS shell around the CdSe multipod NCs, the PL QY of the obtained CdSe/ZnS can be up to 85%. The reported noninjection preparation approach can satisfy the requirement of industrial production bearing the advantage of low-cost, reproducible, and scalable. Furthermore, this facile noninjection strategy provides a versatile route to large-scale preparation of other semiconductor NCs with multipod or other morphologies

Maximizing the Relaxivity of Gd-Complex by Synergistic Effect of HSA and Carboxylfullerene

Macromolecular magnetic resonance imaging (MRI) contrast agent Gd-DTPA-HSA (DTPA, diethylene triamine pentacetate acid; HSA, human serum albumin) as a model has been successfully conjugated with trimalonic acid modified C₆₀ for contrast enhancement at clinically used magnetic field strength. The Gd-DTPA-HSA-C₆₀ conjugate exhibit maximal relaxivity (<i>r</i>₁ = 86 mM^–1 s^–1 at 0.5 T, 300 K) reported so far, which is much superior to that of the control Gd-DTPA-HSA (<i>r</i>₁ = 38 mM^–1s^–1) under the same condition and comparable to the theoretical maximum (<i>r</i>₁ = 80–120 mM^–1 s^–1, at 20 MHz and 298 K), indicating the synergistic effect of HSA and carboxylfullerene on the increased contrast enhancement. TEM characterization reveals that both Gd-DTPA-HSA-C₆₀ and Gd-DTPA-HSA can penetrate the cells via endocytosis and trans-membrane, respectively, suggesting the potential to sensitively image the events at the cellular and subcellular levels. In addition, the fusion of fullerene with Gd-DTPA-HSA will further endow the resulting complex with photodynamic therapy (PDT) property and thus combine the modalities of therapy (PDT) and diagnostic imaging (MRI) into one entity. More importantly, the payloaded Gd-DTPA may substitute for other more stable Gd-DOTA and HSA as a theranostic package can further work as a drug delivery carrier and effectively control drug release through proteolysis