Xu Wang

Cubosomes, a product of nanobioengineering, are self-structured lipid nanoparticles that act like drug-loaded theranostic probes. Here, we describe a simple method for the preparation of combinatorial drug-loaded cubosomes with, proof-of-principle, therapeutic effect against cancer cells, along with diagnostic capabilities. Anticancer drugs cisplatin and paclitaxel were loaded in the cubosomes in combination. The cubosomes were coated with a layer of poly-Ɛ-lysine, which helped avoid the initial burst release of drug and allowed for a slow and sustained release for better efficacy. Cubosomes were imaged by transmission electron microscope, and their dispersion analyzed in vitro by differential scanning calorimetric and X-ray diffractogram studies. The microscopic images depicted spherical polyangular structures, which are easily distinguishable. The analyses revealed that the drug is uniformly dispersed all through the cubosomes. Further characterization was carried out by zeta-potential measurement, in vitro release, and entrapment efficiency studies. The in vitro studies established that the coating of cubosomes successfully reduced the burst release of drugs initially and confirmed a slow, sustained release over increased time. Comparative cytotoxicity of coated, uncoated, and blank cubosomes was evaluated, using human hepatoma HepG2 cell line, and the formulations were found to be entirely nontoxic, similar to the blank ones. The therapeutic efficiency of the cubosomes against HeLa cells was confirmed by the impedance measurement and fluorescent imaging. Furthermore, the reduction in impedance in cells treated with coated combinatorial cubosomes proved the impairment of HeLa cells, as confirmed by fluorescence microscopy.

In the past two decades, layer-by-layer (LbL) assembly has been proven to be a convenient and versatile method to fabricate functional films. However, using traditional dipping LbL assembly to fabricate micrometer-thick films is time consuming. Compared with ultrathin films, micrometer-thick films prepared by LbL assembly possess enhanced mechanical stability, and allow deposition of a significantly increased amount of materials and the integration of multiple functions. These merits of thick films produced by LbL assembly can result in new functions and allow the functions of ultrathin films fabricated by LbL assembly to be optimized. In this tutorial review, the methods for rapid fabrication of thick polymeric films involving LbL assembly are reviewed. The functions of such films that are relevant to their micrometer thickness are discussed.

The influence of the TiO2 particle size on the enhanced Raman spectroscopy properties was systematically investigated on the nanometer-size scale. We report on the enhanced Raman spectrum of 4-mercaptobenzoic acid adsorbed on TiO2 nanoparticles. The results presented in this study highlight the major findings that the intensities of both the molecular lines and the phonon modes of TiO2 are strongly size-dependent. The TiO2 crystallite size estimated using the Scherrer equation varied from 6.8 to 14.2 nm; as a function of crystal size, a large increase in intensity is observed, with a maximum near 10.9 nm and a subsequent decline at larger sizes. Moreover, we have investigated quantum confinement effects between TiO2 and the adsorbed molecules and attribute this to a charge-transfer resonance, which is responsible for the Raman enhancement.

Heal thyself! Exponentially grown layer-by-layer-assembled polyelectrolyte multilayer coatings, which are mechanically robust under ambient conditions, can autonomically repair cuts several tens of micrometers deep and wide when they are simply immersed in water or when water is sprayed on the coatings. The self-healing ability originates from the high flowability of these coatings in water.