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Lipoproteins for Biomedical Applications: Medical Imaging and Drug Delivery
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Pratap C. Naha, Stephen E. Henrich, David P. Cormode, C. Shad Thaxton
While the above-mentioned synthetic HDL mimetic RNAi delivery agents used an inorganic or hybrid core material, organic core materials such as peptides have also been used as scaffolds. Lin et al. recently reported a peptide-phospholipid-based HDL mimetic nanomaterial which was used to encapsulate and deliver cholesterol-modified siRNA [184]. While the group had previously demonstrated in vitro efficacy for this platform, the report details potent knockdown in vivo of bcl-2 protein in KB tumor-bearing mice and inhibition of tumor growth. In a separate report, one group attempted to alter the natural targeting properties of HDLs for SR-B1 in order to avoid accumulation of siRNA in the liver and adrenal glands. The group used a cyclic RGD peptide-modified apoA-1 to encapsulate cholesterol-modified siRNA. This “re-routed” HDL nanoparticle for siRNA delivery demonstrated knockdown of the Pokemon gene in vivo in tumor-bearing mice, tumor growth inhibition, and extended survival [78]. Additionally, a platform previously highlighted in section 4 of this chapter using a single chain variable fragment antibody-apoA-1 fusion protein targeted against CD20+ mantle cell lymphoma cells has also been used to deliver siRNA [185] in addition to hydrophobic drugs.
Gold Nanorods for Diagnostics and Photothermal Therapy of Cancer
Published in Tuan Vo-Dinh, Nanotechnology in Biology and Medicine, 2017
Xiaohua Huang, Mostafa A. El-Sayed
Using the dark field imaging, cancer cells with different marker expression can be detected using Au NRs linked with different targeting ligands. Figure 28.5d through f shows cellular binding of Au NRs on A549 lung cancer cells linked with a single-chain variable fragment (ScFv) peptide, an amino terminal fragment (ATF) peptide, a cyclic RGD peptide, respectively [31]. The ScFv, ATF, and RGD recognize EGFR, urokinase plasminogen activator receptor (uPAR), and the αvβ3 integrin receptor on cancer cells, respectively. By labeling the cells with these conjugates and examination with dark field imaging, the presence and the expression level of these receptors can be obtained. The results shown in Figure 28.5d through f demonstrate that A549 lung cancer cells are overexpressed with EGFR, uPAR, and αvβ3 integrin receptor. The expression level follows in the order of αvβ3 integrin receptor > uPAR > EGFR.
Multifunctional Gold-Based Composites for Theranostics
Published in Lev Dykman, Nikolai Khlebtsov, Gold Nanoparticles in Biomedical Applications, 2017
For GNR labeling, Huang et al. [165] also employed three types of probing molecules. These included (1) a single-chain variable fragment peptide that recognizes the epidermal growth factor receptor, (2) an amino terminal fragment peptide that recognizes the urokinase plasminogen activator receptor, and (3) a cRGD peptide that recognizes the ανβ3 integrin receptor. An important result from that study was that the general effectiveness of particle delivery to the cells depended weakly on the presence of probing molecules but affected strongly the distribution of the particles in the intercellular space.
Progress on electrochemical sensors for the determination of heavy metal ions from contaminated water
Published in Journal of the Chinese Advanced Materials Society, 2018
Xiangzi Dai, Shuping Wu, Songjun Li
Immunosensors are compact analytical devices based on specific antigen–antibody interactions and in which the immunochemical reactions are either directly or indirectly detected by means of a transducer. In electrochemical immunosensors, the event of immunochemical reactions is converted into an electrical signal such as an electric current, a voltage difference or a resistivity change.[21,74–76] The main principle of electrochemical immunosensor for the quantification of heavy metal ions is the change in the current on electrode surface due to oxidation and reduction of adsorbed metal ions. An ultrasensitive electrochemiluminescent (ECL) competitive immunoassay for mercury (II) was developed based on CdSe QDs, gold nanoparticles (GNPs) and specific monoclonal antibody (mAb) against Hg(II).[77] GNPs as substrate and electron transfer accelerator could load more number of coating antigen and magnify the electrochemical signal. Based on this method, Jing et al. developed a cheap and selective GNPs/Ovalbumin-MNA-CH3 Hg/mAb-QDs immunosensor based on the specific mAb against Hg(II). Competitive immunoassay was applied for the detection of Hg(II), and the ECL assay process is depicted in Figure 5(a). The actual size of the thioglycolic acid (TGA) modified CdSe QDs was about 4.6 nm (Figure 5(b)). The possible ECL mechanism could be expressed by the cyclic voltammetry (CV) of the immunosensor (Figure 5(c)). Furthermore, at the range of 0.01 to 50 ng/mL, the logarithm of the mercury (II) concentration change is linear to the decrease of the ECL intensity, with a much lower than previous methods detection limit of 2.6 pg/mL. The immunosensor also exhibit great selectivity to the mercury (II), the result was manifested in the (Figure 5(c)). This ECL immunoassay which applied GNPs as substrate combined with specific mAb detecting Hg(II), is presented for the first time. In addition, Zhu et al. had specifically generated and selected measured environmental uranium with an antibody-based sensor based on recombinant single-chain variable fragment antibodies (scvF).[78] The obtained scvF was complexed to 2,9-dicarboxyl-1,10-phenanthroline-acid (DCP) using genetic material obtained from the spleen cells of rabbits immunized with UO22+—DCP conjugated to keyhole limpet hemocyanin. Recombinant antibody library and phage-displayed antibodies were obtained by amplifying and cloning immunoglobulin light chain and heavy chain genes into the phagemid pSD3. The limit of detection to UO22+ was 2.2 nM, which is below the United States Environmental Protection Agency (US EPA) action limit of 126 nM. In the real sample, the recovery ranged from 84.9% to 124.5% and average sample recovery was 98.89%.