Xingcai Zhang

Drug-loaded polyelectrolyte microcapsules for sustained targeting of cancer cells ☆

In this review we will overview novel nanotechnological nanocarrier systems for cancer therapy focusing on recent development in polyelectrolyte capsules for targeted delivery of antineoplastic drugs against cancer cells. Biodegradable polyelectrolyte microcapsules (PMCs) are supramolecular assemblies of particular interest for therapeutic purposes, as they can be enzymatically degraded into viable cells, under physiological conditions. Incorporation of small bioactive molecules into nano-to-microscale delivery systems may increase drugs bioavailability and therapeutic efficacy at single cell level giving desirable targeted therapy. Layer-by-layer (LbL) self-assembled PMCs are efficient microcarriers that maximize drugs exposure enhancing antitumor activity of neoplastic drug in cancer cells. They can be envisaged as novel multifunctional carriers for resistant or relapsed patients or for reducing dose escalation in clinical settings.

Sonication-assisted synthesis of polyelectrolyte-coated curcumin nanoparticles.

A new method of nanoparticle formulation for poorly water-soluble materials was demonstrated for curcumin. The drug was dissolved in organic solvent that is miscible with water (ethanol), and drug nucleation was initiated by gradual worsening of the solution by the addition of an aqueous polyelectrolyte assisted by ultrasonication. Curcumin crystals of 60-100 nm size were obtained depending on the component concentrations, sonication power, and initial solvent. Layer-by-layer shell assembly with biocompatible polyelectrolytes was used to provide a particle coating with a high surface potential and the stabilization of drug nanocolloids. Polyelectrolyte layer-by-layer encapsulation allowed sustained drug release from nanoparticles over the range of 10-20 h.

Converting Poorly Soluble Materials into Stable Aqueous Nanocolloids

Aqueous nanocolloids of poorly soluble materials were produced via sonicated layer-by-layer (LbL) encapsulation with polycation / polyanion shells. Synergy of simultaneous breaking powder particles with ultrasonication and coating them with polycations allowed for the production of 150-200 nm diameter polyelectrolyte coated nanoparticles with sufficient surface electrical potential for colloidal stability. This technique increases water dispersibility of low soluble materials ranging from anticancer drugs to anticorrosion agents, dyes and inorganic salts.

Top-down and bottom-up approaches in production of aqueous nanocolloids of low solubility drug paclitaxel

Nano-encapsulation of a poorly soluble anticancer drug was demonstrated with a sonication assisted layer-by-layer polyelectrolyte coating (SLbL). We changed the strategy of LbL-encapsulation from making microcapsules with many layers in the walls for encasing highly soluble materials to using a very thin polycation/polyanion coating on low solubility nanoparticles to provide them with good colloidal stability. SLbL encapsulation of paclitaxel resulted in stable 100-200 nm diameter colloids with a high electrical surface ξ-potential (of -45 mV) and drug content in the nanoparticles of 90 wt%. In the top-down approach, nanocolloids were prepared by rupturing a powder of paclitaxel using ultrasonication and simultaneous sequential adsorption of oppositely charged biocompatible polyelectrolytes. In the bottom-up approach paclitaxel was dissolved in organic solvent (ethanol or acetone), and drug nucleation was initiated by the addition of aqueous polyelectrolyte assisted by ultrasonication. Paclitaxel release rates from such nanocapsules were controlled by assembling multilayer shells with variable thicknesses and were in the range of 10-20 h.

Lapatinib/Paclitaxel polyelectrolyte nanocapsules for overcoming multidrug resistance in ovarian cancer.

The sonication-assisted layer-by-layer (SLBL) technology was developed to combine necessary factors for an efficient drug-delivery system: (i) control of nanocolloid size within 100 - 300 nm, (ii) high drug content (70% wt), (iii) shell biocompatibility and biodegradability, (iv) sustained controlled release, and (v) multidrug-loaded system. Stable nanocolloids of Paclitaxel (PTX) and lapatinib were prepared by the SLBL method. In a multidrug-resistant (MDR) ovarian cancer cell line, OVCAR-3, lapatinib/PTX nanocolloids mediated an enhanced cell growth inhibition in comparison with the PTX-only treatment. A series of in vitro cell assays were used to test the efficacy of these formulations. The small size and functional versatility of these nanoparticles, combined with their ability to incorporate various drugs, indicates that lapatinib/PTX nanocolloids may have in vivo therapeutic applications.

Fabrication, mechanical properties, and biocompatibility of reduced graphene oxide-reinforced nanofiber mats

Fibrous functional scaffolds that could mimic the natural growth environment of cells and govern cell-specific behaviors are crucial for meeting the requirements of tissue engineering. Graphene-based materials, which is an important one of them have captured tremendous interests of researchers. However, few research about graphene nanofibers with excellent electrical and mechanical properties have been fabricated and found to have real applications. In this study, we reported a novel PAN-reduced graphene oxide reinforced composite nanofiber mats (rGO–NFMs), which were fabricated by the electrospinning process combined with chemical reduction. SEM, FTIR and XRD revealed that rGO–NFMs were successfully produced. These rGO–NFMs displayed superior mechanical properties (tensile strain and tensile stress are 18.5% and 1.38 MPa, respectively). The cell proliferation and morphology of adipose-derived stem cells (ADSCs as model cells) cultured on the rGO–NFMs were tested with a 7 days culture period. Cellular test results showed that rGO–NFMs exhibited excellent biocompatibility, cells on the nanofibers formed stable cell–fiber constructs, and the rate of cell proliferation was similar to that of tissue culture plates (TCPs) and PAN nanofibers mats (PAN–NFMs). This study demonstrated that rGO–NFMs may be a good choice for application in tissue engineering, particularly cell culture scaffolds for electrical stimulation.

Carbon nanotube/polyurethane films with high transparency, low sheet resistance and strong adhesion for antistatic application

Antistatic technology has been applied in all aspects of modern life, including the manufacture of electronic products, aerospace systems, daily necessities and so on. The main purpose of this study is to obtain, using the Mayer rod-coating method, a flexible antistatic film with high transmittance, low sheet resistance and strong adhesion. With the help of the dispersant, single-walled carbon nanotubes (SWCNTs) were dispersed in water to form an homogeneous dispersion. The SWCNT dispersion was coated onto a poly(ethylene terephthalate) (PET) film with use of a rod to produce a uniform film. The antistatic films obtained had special characteristics, such as high transparency, low sheet resistance and excellent resistance to water and heat. Sheet resistance varied between 102–105 Ω sq−1 by controlling the content of water-based polyurethane (WPU), changing the thickness of the films and the post-treatment. The best film had a sheet resistance of 423 Ω sq−1 with 82.7% transmittance. In particular, the addition of the WPU binder greatly improved the adhesion between the CNTs and the PET film. Scanning electron microscopy, energy dispersive X-ray spectroscopy and Scotch™ tape method were conducted to determine the microstructure, cleanliness, and adhesion of the film, respectively.

Functional nanonetwork-structured polymers with inbuilt poly(acrylic acid) linings for enhanced adsorption

Functional nanonetwork-structured polymers with inbuilt poly(acrylic acid) linings were successfully synthesized by combining surface-initiated atom transfer radical polymerization (SI-ATRP) and hypercrosslinking chemistry, and demonstrated superior adsorption performances toward basic dyes and heavy metal ions.

Smart multifunctional polyurethane microcapsules for the quick release of anticancer drugs in BGC 823 and HeLa tumor cells

Smart multifunctional drug delivery systems (DDSs) based on cytophilic fluorescent polyurethane copolymer microcapsules with high tumor cell internalization, triggered release, quick cancer cell death and real time fluorescent monitoring abilities is developed as a facile and versatile approach for precision cancer therapy.

Composite nanomaterial thin film-based biosensors

This paper reports a new class of biosensors based on composite nanomaterial thin film. The composite nanomaterial film is synthesized using a simple vacuum filtration method. Using composite nanomaterial film, we can not only simplify the positioning and integration fabrication process of nanoscale materials into a functional device, but also enhance the sensing surface area significantly, which might open an opportunity to fabricate devices for ultrasensitive biosensing in a cost-effective way. Systematic measurements find that the composite film, containing carbon nanotubes (CNTs) and SnO2 nanoparticles, shows the similar field effect as that of single CNTs or nanowires (NWs) and its resistance changes upon binding to biomolecules during a bioassay process.