Quantum dot-Insect Neuropeptide Conjugates for Fluorescence Imaging, Transfection, and Nucleus Targeting of Living Cells

Abstract

We identified an insect neuropeptide, namely, allatostatin 1 from Drosophila melanogaster, that transfects living NIH 3T3 and A431 human epidermoid carcinoma cells and transports quantum dots (QDs) inside the cytoplasm and even the nucleus of the cells. QD-conjugated biomolecules are valuable resources for visualizing the structures and functions of biological systems both in vivo and in vitro. Here, we selected allatostatin 1, Ala-Pro-Ser-Gly-Ala-Gln-Arg-Leu-Tyr-Gly-Phe-Gly-Leu-NH2, conjugated to streptavidin-coated CdSe-ZnS QDs. This was followed by investigating the transfection of live mammalian cells with QD-allatostatin conjugates, the transport of QDs by allatostatin inside the nucleus, and the proliferation of cells in the presence of allatostatin. Also, on the basis of dose-dependent proliferation of cells in the presence of allatostatin we identified that allatostatin is not cytotoxic when applied at nanomolar levels. Considering the sequence similarity between the receptors of allatostatin in D. melanogaster and somatostatin/galanin in mammalian cells, we expected interactions and localization of allatostatin to somatostatin/galanin receptors on the membranes of 3T3 and A431 cells. However, with QD conjugation we identified that the peptide was delivered inside the cells and localized mainly to the cytoplasm, microtubules, and nucleus. These results indicate that allatostatin is a promising candidate for high-efficiency cell transfection and nucleus-specific cell labeling. Also, the transport property of allatostatin is promising with respect to label/drug/gene delivery and high contrast imaging of live cells and cell organelles. Another promising application of allatostatin is that the transport of QDs inside the nucleus would lift the limit of general photodynamic therapy to nucleus-specific photodynamic therapy, which is expected to be more efficient than photosensitization at the cell membrane or in the cytoplasm as a result of the short lifetime of singlet oxygen.

Peptides for Specific Intracellular Delivery and Targeting of Nanoparticles: Implications for Developing nanoparticle-mediated Drug Delivery

“…Size-tunable fluorescence emission from UV to near infrared; sensitivity to charge and excellent photosensitizers [35,36,[69][70]85,89,110,115,[122][123] Oxides Iron oxide Magnetic properties for MRI Magnetic contrast properties [71][72]75,83,[91][92][93]98] Polymers Poly(lactic-co-glycolic acid), poly(amido amine) and dendrimers Biocompatibility, biodegradability and controlled release…”

“…Ast 1 (APSGAQRLYGFGL) was identified as a member of a family of 13 neuropeptides that are widely distributed in insects and crustaceans whose receptors are highly homologous to somatostatin and galanin receptors [121]. In 2007, Biju et al identified the peptide's ability to mediate the rapid uptake of commercial streptavidinconjugated QDs after its assembly onto the QD via an avidin-biotin interaction linkage [122]. In NIH 3T3 and A431 cells the QDs were endocytosed and localized primarily within the endosomal compartment upon initial uptake.…”

Biogenic silver nanoparticles from Trichodesma indicum aqueous leaf extract against Mythimna separata and evaluation of its larvicidal efficacy

“…Th erefore, metal nanoparticles could be an improved option for insecticides. It has been reported that nanomaterials possess insecticidal properties (Simonian et al 2005;Biju 2007;Rai et al 2012;Chakravarthy et al 2012). Furthermore, metal nanoparticles are essential components of new biosensors and self--assembled nanodevices (Levy et al 2006;Hsing et al 2007;Bhattacharyya et al 2010).…”

Nanobiodevices for Genome Analysis, Proteome Analysis, and Biomedical Applications

“…7,8,1518,25 The screening of efficiency of siRNA is realized by measuring the FRET signal between QDs-labeled siRNA and Cy5-labeled mRNA as shown in Figure 11. We designed and synthesized several sequences of siRNA, of which sequences are complementary to the sequences of BCR-ABL fusion gene.…”