Small and Stable Sulfobetaine Zwitterionic Quantum Dots for Functional Live-Cell Imaging

Abstract

We have developed a novel surface coating for semiconductor quantum dots (QDs) based on a heterobifunctional ligand that overcomes most of the previous limits of these fluorescent probes in bioimaging applications. Here we show that QDs capped with bidentate zwitterionic dihydrolipoic acid-sulfobetaine (DHLA-SB) ligands are a favorable alternative to polyethylene glycol-coated nanoparticles since they combine small sizes, low nonspecific adsorption, preserved optical properties, and excellent stability over time and a wide range of pH and salinity. Additionally, these QDs can easily be functionalized with biomolecules such as streptavidin (SA) and biotin. We applied streptavidin-functionalized DHLA-SB QDs to track the intracellular recycling of cannabinoid receptor 1 (CB1R) in live cells. These QDs selectively recognized the pool of receptors at the cell surface via SA-biotin interactions with negligible nonspecific adsorption. The QDs retained their optical properties, allowing the internalization of CB1R into endosomes to be followed. Moreover, the cellular activity was apparently unaffected by the probe.

Switchable Materials Containing Polyzwitterion Moieties

“…The formation of micelles, as shown in Figure 3b, improves the protection of the protein against denaturation, shields the negative charge of the protein with polyzwitterionic hairy structure and provides an overall positive surface charge to effect an efficient cellular uptake to tumor cell enhancement; penetration to the tumor cell is also due to the EPR effect. Transformation to the fully zwitterionic state poly (19) by UV irradiation at 365 nm significantly accelerated the release of BSA Figure 3b [62].…”

“…Surface properties such as wettability, biocompatibility, roughness, and adhesiveness can be controlled. Such materials can be further used as self-cleaning materials [16], in drug delivery systems [17][18][19][20][21], for designing controlled permeation membranes [22], in separation [23], etc.…”

Effects of Cannabinoid and Trpv1 in Formalin-induced Orofacial Pain

“…Cannabinoid receptors are largely classified into CB1 receptors 1 . They are found primarily in the central nervous system, and CB2 receptors 2 , which are observed in immune-derived cells. And it has been reported that they are anatomically distributed in the spinal dorsal horn that is involved in the conduction and control of pain.…”

Biocompatibility of quantum dots (CdSe/ZnS ) in human amniotic membrane-derived mesenchymal stem cells in vitro

“…Each of these labeling methods has its own disadvantages, such as low intensity, short labeling time and complicated procedures. Quantum Dots (QDs) are semiconductor nanocrystalloid particles which have a nano-scale character combined with a bright and stable emission spectrum, and can be used to label cells from different sources [5][6][7][8] . We recently received nanoparticle quantum dots from Lanzhou University that are composed of CdSe/ZnS, enabling their detection with a fluorescence microscope 9,10 .…”