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Multimodality probes for cardiovascular imaging
Published in Yi-Hwa Liu, Albert J. Sinusas, Hybrid Imaging in Cardiovascular Medicine, 2017
James T. Thackeray, Frank M. Bengel
A final category of multimodality imaging probe platforms are small molecules, which minimize the connection between different functional imaging agents but often involve complex synthesis procedures. The advantage of this approach is the minimal size of the generated probe, which typically allows for renal clearance and reduced toxicity. Perhaps the simplest approach is the direct radioiodination of fluorophores, providing nuclear imaging functionality to a fluorescence probe (Pandey et al. 2005). Alternatively, Gd has been effectively coupled to rhodamine, fluorescein, coumarin, and spiropyran via DOTA (Mishra et al. 2006; Mizukami et al. 2009; Tu and Louie 2007) and to Oregon Green via DTPA (Dirksen et al. 2004). These probes generally provide excessive fluorescence signal for microscopy due to the ratio of Gd-chelate to fluorescence probe and the necessary dose for effective MR contrast enhancement. Conversely, conjugation of DOTA to cypate has allowed multimodality imaging with 64Cu, 177Lu, or 111In with optical imaging without excessive cypate signal due to the comparable sensitivities of the modalities (Edwards et al. 2008).
The effect of initiator encapsulation on methyl methacrylate polymerization by isothermal differential scanning calorimetry
Published in Journal of Microencapsulation, 2020
Seok Min Lee, Mi Rae Kim, Hee Jung Park, Kang Ho Cheon, Kee Yoon Lee
Credico (2013) used spiropyran, a photochromic dye that changed colour in response to UV, as a core material. Therefore, when a defect occurred in the microcapsule, the dye was exposed to the outside so that the colour was changed by UV and a defect could be visually observed. At this time, polyurea shell was prepared by reacting TDI-based prepolymer and benzophenone-based amine to absorb UV (Credico et al. 2013). The method of encapsulating pigments had been documented (Arunkumar et al. 2005, Oliveira et al. 2005, Credico et al. 2013). Weiss (2015) prepared a microcapsule containing 1-butyl-3-methylimidazolium hexafluorophosphate (BMIm[PF6]) as a core material and polyurea as a shell material, thus avoiding the high viscosity problem of the green solvent ionic liquid (Weiss et al. 2015). Zhou (2017) had also encapsulated a phase change material, a high energy storage density material, as a core material having a polyurea shell to solve the problem of volume expansion (Zhou et al. 2017).
Stimuli-responsive drug delivery systems for head and neck cancer therapy
Published in Drug Delivery, 2021
Jingou Liang, Bina Yang, Xuedong Zhou, Qi Han, Jing Zou, Lei Cheng
Light-stimuli released systems have also been demonstrated in recent DDSs researches. Copolymers with light sensitive and degradable groups could serve as carriers, loaded with various antitumor agents especially chemotherapy drugs. Xing et al. (2015) reported doxorubicin loading spiropyran-containing upconversion nanoparticles. The spiropyran amphiphilic group could be shift to a hydrophilic one with NIR exposure and detach from the copolymer carriers, leading to drug release. The DDS demonstrated active targeting to KB cells and NIR-triggered drug release.
Current progress of miRNA-derivative nucleotide drugs: modifications, delivery systems, applications
Published in Expert Opinion on Drug Delivery, 2022
Charles Asakiya, Liye Zhu, Jieyu Yuhan, Longjiao Zhu, Kunlun Huang, Wentao Xu
Nucleic acid self-assembled nanocarriers can be modified with photosensitizers to trigger the release of drugs and genes under the influence of light. Under this, delivery systems’ stability or structure are distorted under a specific wavelength of external light to cause its cargo release. Visible light irradiation, NIR light, and ultraviolet (UV) are the commonly used light-responsive mode for delivery systems; however, NIR irradiation’s ideal deep tissue penetration makes it more preferable[72]. In 2016, Xiao et al. developed a multi-functional supramolecular hydrogel to control the release of liver-specific miR-122 mimics precisely to HepG2 cells in response to light. They employed a photo-isomerization merocyanine (MC) due to its super-strong ability to foster self-assembling, form spiropyran (SP) when they undergo photo-isomerization, MC-peptide to respond to light, and form hydrogels. Galactose (Gal)-conjugated to SP converted to MC-galactose (Gal) hydrogel. Heating the aqueous solution containing galactose conjugated SP converts SPI-Gal to MCI-Gal, and the MC-Gal gel carrier released miR-122 mimics from the hydrogel when subjected to visible light irradiation[73]. The release efficiency was higher upon mild light irradiation than the buffer, which resulted in a significantly decreased level of the luciferase gene. Meantime, hollow-AuNPs through NIR stimulation response co-delivered both miRNA inhibitor (miR-21i) a chemotherapy drugs Dox for synergistic efficiency[74]. Light-responsive plasmonic gold nanocarrier (AuNR) modified ssDNA complementary to DNA-conjugated miR-302a, and miR-155 (miR-dsDNA-AuNR) triggered the escape of the cargos from a laser stimulus AuNR by the breaking of thiol-gold bonds (Figure 5(b))[75]. The even distribution of miR-155 depicts its successful release due to the cleavage of the disulfide bond causing the disassembly of the delivery system.