Quantum dots (QDs) is a promising candidate for biomedical imaging. However, the bio-toxicity of traditional quantum dots obstructed their further application seriously. In this work, a simple solution growth method was utilized to synthesize ZnO QDs. However, their self-assemble feature makes them unstable in aqueous solution. Furthermore, (3-Aminopropyl) triethoxysilane was selected as a capping agent to stabilize ZnO QDs and then ZnO@SiO2 nanoparticles were obtained. They dispersed excellently in water and exhibited favorable fluorescence properties owing to the protection of silane. The biocompatability of ZnO@SiO2 nanoparticles was verified by MTT assy. The cell affinity studies demonstrated that ZnO@SiO2 nanoparticles could be uptaken by cells efficiently. Therefore, the as-prepared ZnO@SiO2 nanoparticles is a promising candidate for applications in cell imaging.
In this study, we have prepared tumor-targeted hydrophilic UCNPs by coating folate-modified amphiphilic SOC polymer on the surface of OA-UNCPs through hydrophobic interaction. The produced FASOC-UCNPs have excellent optical properties and good dispersibility in aqueous solution. TEM image and FTIR spectra confirm the successful surface modification of OA-UCNPs and folate-conjugation on the UCNPs. Folate-conjugated UCNPs possess active-targeting ability mediated by FR, compared with passive-targeted SOC-UCNP taken up by tumors via the EPR effect. Singlet oxygen production in cancer cells induced by FASOC-UCNP-ZnPc demonstrates the great potential of the nanocomplex as a novel PDT agent based on UCNPs.
KEYWORDS: Nanoparticles, Luminescence, Upconversion, Near infrared, System on a chip, Cancer, Optical properties, FT-IR spectroscopy, Tissue optics, Ytterbium
Upconversion nanoparticles (UCNPs) as a new kind of biological luminescence materials have many advantages comparing with organic fluorescence probes and semi-conductive quantum dots, such as sharp fluorescence
emission, long emission lifetimes, high optical and chemical stability and low toxicity, especially low auto-fluorescence
background and deep tissue penetration under near-infrared (NIR) light excitation for bioimaging. Herein, we
demonstrate a facile approach to transfer UCNPs from hydrophobic to hydrophilic and the use of these UCNPs for cell imaging. Oleic acid-capped UCNPs based on NaYF4 were synthesized and modified with amphiphilic chitosan derivative through hydrophobic interaction. The as-prepared chitosan coated UCNPs with an average diameter of 35 nm were mono-dispersed in aqueous solution and possess good optical properties upon NIR light excitation. Cell viability
assays indicated the low cytotoxicity and good biocompatibility of chitosan-coated UCNPs. Cell imaging results
demonstrated that chitosan-coated UCNPs had great potential for bioimaing and biolabeling. Our work suggests a feasible method to modify OA-UCNPs with amphiphilic polymer and the promise of chitosan-based UCNPs for
bioimaging application.
CdHgTe/SiO2 nanoparticles were prepared by SiO2 capping on the surface of CdHgTe quantum dots
(QDs). The characteristics, such as optical spectra, size and optical stability were investigated. The size
of CdHgTe/SiO2 nanoparticles could be larger than 100 nm after CdHgTe QDs capped with SiO2.
CdHgTe/SiO2 nanoparticles acted as a novel fluorescence probe have a maximum fluorescence
emission of 790 nm and a full width at half-maximum (FWHM) of 50-70 nm. The in vivo fluorescence
imaging of CdHgTe/SiO2 nanoparticles in mouse model indicated the nanoparticles could be passively
targeting to lung and liver. CdHgTe/SiO2 nanoparticles offer new perspectives for size dependent
bio-dstribution studies in living body.
Signal transducer and activator of transcription (STAT) 5b is an important protein in JAK-STAT signal pathway and is
responsible for the metastasis and proliferation of tumor cells. The determination of the STAT5b expression provides a
way to study the mechanism of tumor progress. In this study, gold nanoparticles with different diameters were
conjugated to the fluorescein modified STAT5b specific DNA sequence to form the beacon. The procedures for the
beacon with better fluorescence properties were optimized. The fluorescence quenching and the recovery properties after
hybridizing with mRNA of STAT5b were intensively investigated. Results indicate the gold nanoparticle based beacon
is an effective probe for the determination of STAT5b protein expression in JAK-STAT signal pathway and has great
potential in the study of drug screening and discovery.
KEYWORDS: Tumors, Near infrared, In vivo imaging, Tissues, Nanoparticles, Luminescence, System on a chip, Cancer, Magnetic resonance imaging, Imaging systems
The development of more selective delivery systems for cancer diagnosis and chemotherapy is one of the most
important goals of current anticancer research. The purpose of this study is to construct and evaluate the folate-decorated,
self-assembled nanoparticles as candidates to deliver near infrared fluorescent dyes into tumors and to investigate the
mechanisms underlying the tumor targeting with folate-decorated, self-assembled nanoparticles. Folate-decorated
N-succinyl-N'-octyl chitosan (folate-SOC) were synthesized. The chemical modification chitosan could self-assemble
into stable micelles in aqueous medium. Micelle size determined by size analysis was around 140 nm in a
phosphate-buffered saline (PBS, PH 7.4). Folate-SOC could maintain their structure for up to 15 days in PBS. Near
infrared dye ICG-Der-01 as a mode drug was loaded in the micelles, and the entrapment efficiency (EE) and drug
loading (DL) were investigated. The targeted behavior of folate-SOC was evaluated by near-infrared fluorescence
imaging in vivo on different groups of denuded mice, with A549 or Bel-7402 tumors. The optical imaging results
indicated that folated-decorated SOC showed an excellent tumor specificity in Bel-7402 tumor-bearing mice, and weak
tumor specificity in A549 tumor bearing mice. We believe that this work can provide insight for the engineering of
nanoparticles and be extended to cancer therapy and diagnosis so as to deliver multiple therapeutic agents and imaging
probes at high local concentrations.
Nanoparticles have a promising application prospect in biomedical field. The study of their dynamic characteristics
including in vivo distribution and clearance has the most important significance on their biological application. In this
paper, bio-distribution and clearance of solid and colloid nanoparticles with different size in mouse model was
intensively studied in vivo by using near infrared optical imaging technique. Here, nanohydrogels were synthesized by
precipitation polymerization method and the size of the nanohydrogel could be arbitrarily manipulated according to
different surfactant concentration. Near infrared fluorescence dye were entrapped into their inner core for in vivo studies.
Meanwhile, the size of CdHgTe/SiO2 solid nanoparticles could be controlled by the thickness of SiO2 coated on the
surface of CdHgTe. The results from the near infrared imaging showed that nanohydrogels with different size have the
similar tissue distribution but CdHgTe/SiO2 nanoparticles in different size have a size-dependent organ specification.
These results provided an important reference for the design of targeted drug delivery systems and their biomedical
applications.
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