Ninglin Zhou

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.

Graphene oxide and adenosine triphosphate as a source for functionalized carbon dots with applications in pH-triggered drug delivery and cell imaging

A folate-functionalized carbon dot-based nanocarrier system has been successfully synthesized for cancer cell targeted drug delivery. We hydrothermally synthesized blue photoluminescent N,P-CDs using adenosine triphosphate and graphene oxide as the starting materials. The particle size of the N,P-CDs was ca. 3.8xa0nm. An anticancer drug, doxorubicin (DOX), was grafted onto the carbon dots via electrostatic interactions, and a more specific anticancer agent (DOX/N,P-CDs) was obtained. The DOX/N,P-CDs were characterized by H-NMR, C-NMR and UV-vis analysis. In addition, the DOX/N,P-CDs showed a pH-dependent release and were easily absorbed by cells. When compared to DOX, DOX/N,P-CDs nanoparticles exhibited the same cytotoxicity towards human cervical cancer cells (HeLa cells) and human pulmonary adenocarcinoma cells (A549 cells). Hemolysis test results indicated that DOX/N,P-CDs were safe for blood-contact applications and were suitable for intravenous administration. Owing to their intrinsic biocompatibility, N,P-CDs can be used for cell imaging and drug delivery with excellent targeting property.

Novel GO-COO-β-CD/CA inclusion: its blood compatibility, antibacterial property and drug delivery

Abstract GO-COO-β-CD/CA inclusion (carboxylated graphene-β-cyclodextrin/chlorhexidine acetate) was fabricated with a graphene-based drug carrier. The reaction time and ratio of carrier to drug were optimized by X-ray diffraction spectra to ensure the complete wrapping of CA. Hemolysis test and recalcification test demonstrated that the inclusion possessed good blood compatibility due to the inherent biocompatibility of β-CD molecules in the carrier. The inclusion displayed excellent inhibition effect on both gram negative bacteria of Escherichia coli and gram positive bacteria of Staphylococcus Aureus, while showing no cytotoxicity. More importantly, the drug efficiency was greatly improved with CA dosage as less as one-third of the pure drug due to the synergistic effect of the drug and carrier. Dynamic simulation implies that the delivery profile of CA from the inclusion is in accordance with the first-order dynamic equation, i.e. ln(1-Mt/M)u2009=u2009−kt.

Preparation of fluorescent N,P-doped carbon dots derived from adenosine 5'-monophosphate for use in multicolor bioimaging of adenocarcinomic human alveolar basal epithelial cells

AbstractCarbon quantum dots doped with nitrogen and phosphorus were prepared from adenosine 5′-monophosphate (AMP) in a single simple synthesis step. The nitrogen and phosphorus doped C-dots (N,P-C-dots) were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy and X-ray powder diffraction. These carbon dots display blue fluorescence, with excitation/emission maxima at 360/430xa0nm, a quantum yield of 26.5% and an average decay time of 4.3xa0ns. Fluorescence is strongest at neutral pH values but quenched at very high and very low pH values. It is also quenched by ferric ions which suggests the usexa0of thexa0N,P-C-dots as fluorescent probes for Fe(III). A hemolysis test inferred favorable blood compatibility. The fluorescence of the doped C-dots is excitation wavelength dependent and also is susceptible to 2-photon excitation. The nanoparticles were applied in the fluorescent multicolor bioimaging of A549 (adenocarcinomic alveolar basal epithelial) cells under different excitation wavelengths, typically at 405, 488 and 543xa0nm. Emission colors ranging from blue to green and red can be adjusted in this way.n Graphical abstractNitrogen and phosphorus doped carbon dots were synthesized and showed excitation wavelength-dependent behavior. They were applied to multi-color fluorescence imaging of adenocarcinomic alveolar basal epithelial cells.

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.

GO-COO-HP-β-CD nanosphere: a complex construction and its drug-loading properties

A novel nanosphere based on carboxylated GO (GO-COOH) and hydroxypropyl-beta-CD (HP-β-CD) was synthesized to construct a complex of GO-COO-HP-β-CD. The complex formation process was studied using spectral characterization and transmission electron microscopy (TEM). X-ray diffraction and energy dispersive spectroscopy patterns show that HP-β-CD molecules either cover or intercalate into GO-COOH interlayers in the complex. Fourier transform infrared spectroscopy results indicate that GO-COOH and HP-β-CD are linked with covalent bonds formed via esterification. When employed as nanohybrid drug carriers for dexamethasone, the inclusion displays good dispersibility validated by dynamic light scattering (DLS). Cytotoxicity assays and hemolysis testing demonstrate that the nanospheres possess good biological compatibility. The loading capacity of dexamethasone is as high as 32.33%, with loading efficiency 64.66%.

Near-infrared light-mediated photodynamic/photothermal therapy nanoplatform by the assembly of Fe 3 O 4 carbon dots with graphitic black phosphorus quantum dots

Background Recently, combined photodynamic therapy (PDT) and photothermal therapy (PTT) has become a desired treatment for cancer. However, the development of economic, high-efficiency, and safe photosensitizers/photothermal agents remains a significant challenge. Methods A novel nanocomposite has been developed via the assembly of iron oxide carbon dot (Fe3O4-CDs) nanoparticles and black phosphorus quantum dots (genipin [GP]-polyglutamic acid [PGA]-Fe3O4-CDs@BPQDs), and this nanocomposite shows a broad light-absorption band and a photodegradable character. Results In vitro and in vivo assays indicated that GP-PGA-Fe3O4-CDs@BPQDs were highly biocompatible and exhibited excellent tumor-inhibition efficacy, due to the synergistic PTT and PDT via a near-infrared laser. Importantly, in vivo tumor magnetic resonance imaging (MRI) results illustrated that GP-PGA-Fe3O4-CDs@BPQDs can be specifically applied for enhanced T2 MRI of tumors. This work presents the first combined application of a PDT and PTT effect deriving from BPQDs and MRI from Fe3O4-CDs, which may promote utilization of black BPQDs in biomedicine. Conclusion As expected, GP-PGA-Fe3O4-CDs@BPQDs displayed a dramatically enhanced ability to destroy tumor cells, due to the synergistic combination of PTT and PDT.

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.