Study on the intracellular fate of Tat peptide-conjugated quantum dots by spectroscopic investigation

Beauty is skin deep: a surface monolayer perspective on nanoparticle interactions with cells and bio-macromolecules

Surface recognition of biosystems is a critical component in the development of novel biosensors and delivery vehicles, and for the therapeutic regulation of biological processes. Monolayer-protected nanoparticles present a highly versatile scaffold for selective interaction with bio-macromolecules and cells. Through the engineering of the monolayer surface, nanoparticles can be tailored for surface recognition of biomolecules and cells. This review highlights recent progress in nanoparticle-bio-macromolecule/cellular interactions, emphasizing the effect of the surface monolayer structure on the interactions with proteins, DNA, and cell surfaces. The extension of these tailored interactions to hybrid nanomaterials, biosensing platforms, and delivery vehicles is also discussed.

Enhancement of intracellular delivery of anti-cancer drugs by the Tat peptide

The arginine-rich cationic Tat peptides have been reported to enhance the intracellular delivery of macromolecules, including DNA, RNA, and proteins. In this work an arginine cationic peptide derived from the HIV-1 Tat protein was conjugated with noncovalent bonds to sulfonated aluminum phthalocyanine (AlPcS, a photosensitizer for the light-activated photodynamic cancer therapy), doxorubicin (DOX, a chemotherapeutic agent), or quantum dots (QDs, often used as carriers for the delivery of anticancer drugs). The fluorescence of intracellular conjugates of AlPcS-Tat, DOX-Tat, and QDs-Tat was studied by means of confocal laser scanning microscopy in the human nasopharyngeal carcinoma KB cells and cervical carcinoma Hela cells in vitro. The Tat peptide with noncovalent links can enhance at least a twofold of intracellular delivery of AlPcS, DOX, and QDs via an endocytotic pathway in the two tumor cell lines. This finding may suggest that the Tat peptide-mediated intracellular delivery of anticancer drugs may have the potential for improving efficacy of cancer therapy.

Spatially selective assembly of quantum dot light emitters in an LED using engineered peptides

Semiconductor nanocrystal quantum dots are utilized in numerous applications in nano- and biotechnology. In device applications, where several different material components are involved, quantum dots typically need to be assembled at explicit locations for enhanced functionality. Conventional approaches cannot meet these requirements where assembly of nanocrystals is usually material-nonspecific, thereby limiting the control of their spatial distribution. Here we demonstrate directed self-assembly of quantum dot emitters at material-specific locations in a color-conversion LED containing several material components including a metal, a dielectric, and a semiconductor. We achieve a spatially selective immobilization of quantum dot emitters by using the unique material selectivity characteristics provided by the engineered solid-binding peptides as smart linkers. Peptide-decorated quantum dots exhibited several orders of magnitude higher photoluminescence compared to the control groups, thus, potentially opening up novel ways to advance these photonic platforms in applications ranging from chemical to biodetection.