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Abstract Serum albumin has a wide range of applications in biochemical experiments and pharmaceutical field. We found that a cyanine dye, dimethylindole red (Dir), could selectively interact with bovine serum albumin (BSA). Dir exhibited very weak red fluorescence, while the fluorescence intensity at 630 nm was enhanced up to 130-fold upon noncovalently interacting with 30 µM BSA. Besides, Dir showed a highly selective response to BSA over human serum albumin (HSA). For the detection of BSA, a limit of detection as low as 23 nM was obtained. Then biocompatible Dir-BSA nanoparticles were prepared by the desolvation technique. The Dir-BSA nanoparticles possess excellent fluorescence properties with a quantum yield of 32%. Furthermore, folic acid as a targeting group was conjugated to Dir-BSA nanoparticles and these nanoparticles were characterized by TEM and laser particle analyzer, etc. Folic acid-modified Dir-BSA nanoparticles were successfully used for tumor cell-targeted imaging. Graphical abstract fx1 Highlights • Dir could selectively interact with BSA compared with HSA. • The fluorescence of Dir is increased up to 130-fold upon binding to BSA. • Dir-BSA nanoparticles possess a fluorescence quantum yield of ca. 32%. • The folate modified Dir-BSA NPs could be used for targeted tumor cell imaging. [ABSTRACT FROM AUTHOR]

Abstract Long-term live cell tracking is desirable and necessary to understand the dynamics and complexity of biological interactions in stem cells and cancer cells. Conventional live cells fluorescence trackers are generally non-degradable and are showing increased toxicity concerns during the long-term application. Previously we developed biodegradable fluorescent poly(citrate)-based hybrid elastomers for bone regeneration applications. Here, we fabricated the photoluminescent poly(citrate-siloxane) nanoparticles (PCSNPs) through an oil/water emulsion method and demonstrated their long-term live stem cells/cancer cells imaging applications. PCSNPs showed a uniform size distribution (mean diameter 120 nm) and highly stable dispersability (above 30 days) in various physiological medium, as well as excellent fluorescent properties and photostability. PCSNPs possess excellent cellular biocompatibility, which could be efficiently internalized by cells and selectively image the cell lysosome with a high photostability. Compared with commercial Cell Tracker™ Green and Cell Tracker™ Red, the adipose-derived mesenchymal stem cells or human hepatoma cells were stably labeled by PCSNPs for over 14 days as they grew and developed (7 passages). Additionally, PCSNPs efficiently tracked cells up to 7 days in vivo through a non-invasively way compared with 1 day of commercial tracker. This study demonstrates an important strategy to design biodegradable multifunctional delivery platforms for biomedical applications such as long-term bioimaging. Graphical abstract Unlabelled Image Highlights • Biodegradable PCS nanoparticles were fabricated through a facile emulsion technology. • PCSNPs showed a monodispersed size (120 nm) and highly stable dispersability. • PCSNPs exhibited excellent fluorescent properties and photostability. • PCSNPs possess excellent cellular biocompatibility and long term cell tracking. [ABSTRACT FROM AUTHOR]

A bioorthogonal Raman reporter-embedded Au-core and polydopamine-shell nanoprobe was initially designed and synthesized for live cell surface-enhanced Raman scattering (SERS) imaging in Raman-silent region. The firstly synthetic bioorthogonal Raman reporter (E)-2- ((4-(phenylethynyl) benzylidene)amino)ethanethiol (PBAT) provided intense Raman signal at 2220cm-1 in Raman-silent region. And its synthetic method was environmentally benign, high yield and easy in operation. In addition, the hydrophobicity of PBAT led to slightly aggregation of gold nanoparticles, which enhance the SERS intensity of the nanoprobe through hot spots. Furthermore, owing to the remarkable biocompatibility of polydopamine (PDA), the SERS nanoprobe can be smoothly internalized into cancer cells to realize SERS imaging in Raman-silent region. Finally, the SERS mapping results confirmed that nanoprobe exhibited strong SERS signal intensity, excellent stability in complex biological environment and low toxicity inside live cancer cells. Therefore, the reporter-embedded core-shell nanoprobe has enormous potential of applications in biomedical diagnostics in the near future. Graphical abstractHighlights· One-step synthetic method of thiol and alkynyl contained bioorthogonal SERS reporter is environmentally benign, high yield and easy in operation. · Au@PBAT@PDA nanoparticles exhibit strong SERS signal intensity, excellent stability in complex biological environment. · Au@PBAT@PDA nanoparticles show good imaging results for live cancer cell SERS imaging in Raman-silent region. · The rich functional groups (i.e., catechol and amine) on PDA surface provide a broad platform for further modification in biomedical application. · A Raman-silent region nanoprobe was synthesized for live cell SERS imaging. [ABSTRACT FROM AUTHOR]

Abstract: We report fluorescence behavior in non-functionalized carbon nanoparticles (NCNP) prepared from lamp soot and their application in imaging of normal and cancer cells. Structural characterization of these particles by Raman spectroscopy showed characteristic peaks located at 1350 and 1590cm−1 corresponding to the diamond-like (D) and graphite-like (G) bands of the carbon allotropes respectively with the characteristic ratio I D /I G =2.24. X-ray diffraction study confirmed the presence of amorphous as well as graphitized carbon in these nanostructures with minimum grain size ≈2nm. A typical luminescence lifetime measured by time resolved fluorescence spectroscopy was obtained 3.54ns. The photoluminescence behavior of these particles was excitation dependent and gave off blue, green and red fluorescence under UV, blue and green excitation, respectively. Cellular uptake of these NCNP yielded excellent results for cell imaging of human embryonic kidney, lung carcinoma and breast adenocarcinoma cells. Cell imaging was further correlated with cytotoxicity in the above mentioned cell lines and also in leukemia cell lines. Dose dependant cytotoxicity was observed after 24h up to 48h of incubation of nanoparticles. Fluorescence microscopy of nanoparticle-cell interaction clearly indicated aggregation of the particles. [Copyright &y& Elsevier]

Abstract: Synthesis of a highly dispersed hydrophilic CdS nanocrystals and their use as fluorescence labeling for live cell imaging is reported here. By carefully manipulating the surface of CdS nanocrystals, the dispersions of CdS–MAA–PEI–FA nanocrystals with high photostability is prepared. The receptor-mediated delivery of folic acid conjugated quantum dots into folate-receptor-positive cell lines such as CBRH7919 liver cancer cells was demonstrated by confocal microscopy. In the future, the further modified CdS nanoparticles can be used for the tissue imaging in vivo studies. [Copyright &y& Elsevier]

Abstract: We report a class of polysaccharide-based hybrid nanogels that can integrate the functional building blocks for optical pH-sensing, cancer cell imaging, and controlled drug release into a single nanoparticle system, which can offer broad opportunities for combined diagnosis and therapy. The hybrid nanogels were prepared by in-situ immobilization of CdSe quantum dots (QDs) in the interior of the pH and temperature dual responsive hydroxypropylcellulose-poly(acrylic acid) (HPC-PAA) semi-interpenetrating polymer networks. The–OH groups of the HPC chains are designed to sequester the precursor Cd2+ ions into the nanogels as well as stabilize the in-situ formed CdSe QDs. The pH-sensitive PAA network chains are designed to induce a pH-responsive volume phase transition of the hybrid nanogels. The developed HPC-PAA-CdSe hybrid nanogels combine a strong trap emission at 741nm for sensing physicochemical environment in a pH dependent manner and a visible excitonic emission at 592nm for mouse melanoma B16F10 cell imaging. The hybrid nanogels also provide excellent stability as a drug carrier, which cannot only provide a high drug loading capacity for a model anticancer drug temozolomide, but also offer a pH-triggered sustained-release of the drug molecules in the gel network. [Copyright &y& Elsevier]

Hybrid Core-Shell Nanostructures: Integrating Biofunctionalized Polysaccharide-Drug Conjugates with Fluorescent Semiconductor Nanocrystals against Cancer. • New biofunctional quantum dot/polysaccharide/folate nanoconjugates were produced. • Cu-In-S/ZnS-CMC core-shell hybrid conjugates produced by facile green aqueous process. • ZCIS-CMC conjugates acted as non-toxic optical nanoprobes for bioimaging cancer cells. • Cu-In-S/ZnS-CMC nanocolloids biofunctionalized by folate targeted breast cancer cells. • ZAIS-CMC-FA/DOX acted as targeted-drug delivery nanocarriers for killing cancer cells. Although the field of oncology nanomedicine has shown indisputable progress in recent years, cancer remains one of the most lethal diseases, where the early diagnosis plays a pivotal role in the patient's prognosis and therapy. Herein, we report for the first time, the synthesis of biocompatible nanostructures composed of Cu-In-S and Cu-In-S/ZnS nanoparticles functionalized with carboxymethylcellulose biopolymer produced by a green aqueous process. These inorganic-organic colloidal nanohybrids developed supramolecular architectures stabilized by chemical functional groups of the polysaccharide shell with the fluorescent semiconductor nanocrystal core, which were extensively characterized by several morphological and spectroscopical techniques. Moreover, these nanoconjugates were covalently bonded with folic acid via amide bonds and electrostatically conjugated with the anticancer drug, producing functionalized supramolecular nanostructures. They demonstrated nanotheranostics properties for bioimaging and drug delivery vectorization effective for killing breast cancer cells in vitro. These hybrids offer a new nanoplatform using fluorescent polysaccharide-drug conjugates for cancer theranostics applications. [ABSTRACT FROM AUTHOR]

• This review provides the application of exosomes as potential candidate in drug delivery, imaging and gene therapy. • We present an overview on the structure of exosomes, isolation, loading drug or molecules. • In this paper, we discuss many of the current challenges, future development and their interaction into clinical practice. Exosomes are biological nanoparticles (30−150 nm) secreted in the extracellular area from all of cells, that mediate intercellular message. Exosomes act as the carriers for numerous proteins, DNAs, RNAs and cell-signaling molecules. Therefore, exosomes secreted by the tumor cells are useful for diagnostic purposes because of their persistent presence in the blood and their provision of genetic cargo similar to those in tumor. Due to the risks of aggressive activity and ambiguity of biological activity in other tissues, the use of exosomes in drug delivery and imaging has been limited. However, their high loading, stability and longer circulation time, excellent targeting, high cell penetration performance, and optimal biodegradability have made them potential agents in targeted cancer treatment. Therefore, in addition to examining methods for isolating and loading exosomes, this paper discusses the applications of exosomes in biological measurement, imaging, and therapeutic activities. Also, this review describes the challenges of using exosomes compared to conventional methods and shows that it is very useful to use them due to less aggressive activities. Finally, this review attempts to provide an appropriate incentive by showing the performance of exosomes in cancer therapy through targeted drug delivery, gene therapy, imaging and diagnosis. [ABSTRACT FROM AUTHOR]