Ping Yuan

A hydrothermal route to multicolor luminescent carbon dots from adenosine disodium triphosphate for bioimaging

In this work, phosphor and nitrogen co-doped carbon dots (N-P-doped CDs) were developed for bioimaging. The as-synthesized N-P-doped CDs emit a bright blue coloured fluorescence after exposure to a 365nm UV-lamp illumination. It is also demonstrated that the fluorescence of CDs is resistant to the interference of metal ions, saline solution, and high ionic strength environments. The bright fluorescence nature of the N-P-doped CDs has proven them to be excellent probes for cellular imaging. And this guess is further confirmed by using a laser scanning confocal microscope (LSCM). The viability study was carried out by MTT assay, suggesting the high biocompatibility of N-P-doped CDs. The results demonstrated that N-P-doped CDs may be considered as a safe material for bio-imaging and drug delivery in cancer cells.

pH-Sensitive N-doped carbon dots–heparin and doxorubicin drug delivery system: preparation and anticancer research

In this study, doxorubicin (DOX) hydrochloride as a model drug, N-doped carbon dots as a drug carrier, and heparin as an auxiliary medicine were selected to design and prepare a multi-functional drug delivery system with pH-triggered drug release. The CDs were anchored onto heparin via chemical bonds and DOX was then loaded on CDs–Hep by taking advantage of the electrostatic interactions between DOX and CDs–Hep. The structures of all the intermediates and final products were characterized and confirmed by 1H NMR and FT-IR spectroscopies. The CDs–Hep/DOX drug delivery system exhibited good stability. However, in acidic buffer, Hep and DOX release rate was accelerated and it was pH-responsive. In vitro and in vivo studies confirmed the high biocompatibility and low-toxicity of the CDs. An MTT assay showed that inhibition rate of CDs–Hep/DOX for HeLa, MCF-7 and A549 cells was close to that of DOX, indicating that the prepared drug system has a higher toxicity for tumor cells and can achieve an effective therapeutic effect. This systemic evaluation suggests that the introduction of Hep improves blood compatibility. In addition, the internalization of CDs–Hep/DOX by A549 cells was further confirmed using laser scanning confocal microscopy. As a result, a therapy was achieved due to the incorporation of Hep and DOX.

Carboxylated graphene oxide functionalized with β-cyclodextrin—Engineering of a novel nanohybrid drug carrier

In this paper, we selected biocompatible carboxylated graphene oxide (GeneO-COOH) as a base material. The nanohybrid drug carriers composed of GeneO-COOH and cyclodextrin (β-CD), have been successfully synthesized through esterification and self-assembly technique. The nanohybrid drug carriers of GeneO-COO-β-CD were characterized by X-ray diffraction (XRD), fourier infrared spectroscopy (FTIR), thermogravimetric analysis (TG), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and solubility experiments. Results indicated that the nanohybrid was obtained with GeneO-COOH forming the core and a large number of β-CD molecules forming the shell with a special structure. In the nanohybrid, the westerification between GeneO-COOH and β-CD led to the formation of covalent bonds, while adjacent β-CD molecules engineer an outer shell composed of 100 β-CD molecules (ca. 800nm of thickness) in the form of a layer-by-layer self-assembly due to hydrogen-bonding interaction. The obtained novel nanohybrid drug carriers of GeneO-COO-β-CD possessed good dispersibility in water media and the solutions were found to remain stable for 12 months，providing a possibility for further applications in biology, medicine, agriculture and other fields.

Anticoagulant Polyurethane Substrates Modified with Poly(2-methacryloyloxyethyl phosphorylcholine) via SI-RATRP

A novel catalyst system of Reverse Atom Transfer Radical Polymerization (RATRP) to prepare Polyurethane (PU) films modified by poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) was studied in this article. In this system, PU film was pretreated by LaCl3/CA ethanol solution to obtain a hydrated surface allowing more initiators to be immobilized on it. Moreover, complexes composed of silane coupling agent 3-chloropropyltrimethoxysilane (CPTM), chlorhexidine acetate (CA) and lanthanum(III) worked as ligands of copper ions as a whole during RATRP process. PU films before and after modification were characterized by X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA) to confirm that pMPC chains were successfully grafted from the substrates. Results of Plasma recalcification time assay, platelet adhesion test indicated excellent blood compatibility. Furthermore, the antibacterial activity of the material have been improved which proved by adhesion test of E.coil.

Study on montmorillonite–chlorhexidine acetate–terbinafine hydrochloride intercalation composites as drug release systems

This paper focuses on the intercalation of chlorhexidine acetate (CA) and terbinafine hydrochloride (TBH) into montmorillonite as sustained release drug carriers. The intercalation compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The basal spacing of montmorillonite increased from 1.23 to 2.97 nm. It was confirmed that CA and TBH molecules were well-stabilized in the interlayer space of clay via mono-, double or triplicate layer stacking. The adsorption amounts and molecular structures of CA and TBH appeared to depend on the cation exchange capacity of MMT, which in turn, tailored the drug release patterns. In vitro release tests of MMT–CA–TBH in 0.9 wt% NaCl solution at 37 °C show a biphasic and sustained profile of CA and TBH ion release. After release, dissolution–diffusion kinetic models were fitted. The mechanism of MMT–CA–TBH release is probably due to surface diffusion and bulk diffusion via ionic exchange of MMT ions on or in the MMT with ions in the NaCl solution. The in vitro release experiments revealed that CA and TBH were released from MMT steadily, depending on the cooperation between the drugs themselves and the electrostatic interactions between the drugs and MMT. It was found that the cross-linking ratio increased due to a decrease in the free volume available for diffusion.

N-Doped CDs–GP nanospheres as a drug delivery nanocarrier system with carbon dots and a fluorescent tracer

In this study, a carbon dots-genipin covalent conjugate (CDs–GP) was synthesized, characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and fluorescence spectroscopy (FL). These carbon dots displayed three dimensional spherical structures with uniform diameters, blue fluorescence (excitation/emission maxima at 355/455 nm), and high water dispersion with a zeta potential of +17.1 mV. Moreover, the CDs–GP conjugate showed excellent biocompatibility with HeLa and A549 cells. Furthermore, the blood compatibility of CDs–GP was evaluated by hemolysis, and hemolysis rates were less than 5%. We deem that combining the outstanding properties of GP with CDs could further promote the development of CDs in biological applications, achieving multifunctional CDs with targeting, in vivo imaging and therapeutic-delivery capabilities. Our in vitro results demonstrated the high uptake of the CDs–GP by cells. Significantly, the prepared CDs–GP exhibited strong optical absorbance under 635 nm laser irradiation, thus the present research demonstrated that the prepared CDs–GP could be employed as a near infrared (NIR)-absorbing agent as well as a non-toxic drug carrier, realizing the synergistic treatment of photothermal therapy (PTT) and drug delivery. The release of heparin (Hep) could be selectively stimulated by NIR-light and low pH, enabling intracellular drug accumulation and thereby enhancing the efficiency. Overall, all these data suggest that the CDs–GP conjugate has a potential application as a drug delivery system and PTT agent.