SERS and integrative imaging upon internalization of quantum dots into human oral epithelial cells

Imaging and SERS Study of the Au Nanoparticles Interaction with HPV and Carcinogenic Cervical Tissues

In this work, gold NPs were prepared by the Turkevich method, and their interaction with HPV and cancerous cervical tissues were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal and multiphoton microscopy and SERS. The SEM images confirmed the presence and localization of the gold NPs inside of the two kinds of tissues. The light absorption of the gold NPs was at 520 nm. However, it was possible to obtain two-photon imaging (red emission region) of the gold NPs inside of the tissue, exciting the samples at 900 nm, observing the morphology of the tissues. The infrared absorption was probably due to the aggregation of gold NPs inside the tissues. Therefore, through the interaction of gold nanoparticles with the HPV and cancerous cervical tissues, a surface enhanced Raman spectroscopy (SERS) was obtained. As preliminary studies, having an average of 1000 Raman spectra per tissue, SERS signals showed changes between the HPV-infected and the carcinogenic tissues; these spectral signatures occurred mainly in the DNA bands, potentially offering a tool for the rapid screening of cancer.

Glycan Nanobiosensors

This review paper comprehensively summarizes advances made in the design of glycan nanobiosensors using diverse forms of nanomaterials. In particular, the paper covers the application of gold nanoparticles, quantum dots, magnetic nanoparticles, carbon nanoparticles, hybrid types of nanoparticles, proteins as nanoscaffolds and various nanoscale-based approaches to designing such nanoscale probes. The article covers innovative immobilization strategies for the conjugation of glycans on nanoparticles. Summaries of the detection schemes applied, the analytes detected and the key operational characteristics of such nanobiosensors are provided in the form of tables for each particular type of nanomaterial.

Membrane reorganization after photochemical internalization to release transferrin-biofunctionalized polystyrene microparticles

Therapeutic drug carriers can drive their cargo to their target cells. However, an obstacle is usually the entrapment of the drug inside the endolysosomal compartment, which physically impedes its actuation by the impossibility of reaching its molecular site of action. To overcome this hurdle, photochemical internalization (PCI) has been proposed, but the extent of PCI-induced membrane disruption and its capability to allow the release of microparticles is unknown. The aim of the present study was to determine if PCI allows the release of microparticles from the endolysosomal compartment to the cytosol and to analyze at the ultrastructural level the effect of PCI on the membrane surrounding the particles. Confocal microscope allowed us to detect that endolysosomal membranes suffered some disruption after PCI, evidenced by the diffusion of soluble transferrin from the endolysosomes to the cytosol and by a decrease of LAMP1-microparticles co-localization. Transmission electron microscopy (TEM) showed a decrease in the number of well-defined membranes around microparticles after PCI, and scanning TEM combined with energy dispersive x-ray revealed an increase in the width of endolysosomal membranes after treatment. These results suggest that endolysosomal membranes suffered an ultrastructure alteration after PCI, enough to liberate soluble transferrin but not the entire microparticles.

The conformation of bovine serum albumin adsorbed to the surface of single all-dielectric nanoparticles following light-induced heating

Interaction between nanoparticles and biomolecules leads to the formation of biocompatible or bioadverse complexes. Despite the rapid development of nanotechnologies for biology and medicine, relatively little is known about the structure of such complexes. Here, we report on the changes in conformation of a blood protein (bovine serum albumin) adsorbed on the surface of single all-dielectric nanoparticles (silicon and germanium) following light-induced heating to 640 K. This protein is considerably more resistant to heat when adsorbed on the nanoparticle than when in solution or in the solid state. Intriguingly, with germanium nanoparticles this heat resistance is more pronounced than with silicon. These observations will facilitate biocompatible usage of all-dielectric nanoparticles.

Fabrication by Laser Irradiation in a Continuous Flow Jet of Carbon Quantum Dots for Fluorescence Imaging

Fluorescent carbon quantum dots (CQDs) are synthesized by laser irradiation of carbon glassy particles suspended in polyethylene glycol 200 by two methods, a batch and a flow jet configuration. The flow jet configuration is carried out by the simple combination of common laboratory objects to construct a home-made passage reactor of continuous flow. Despite the simplicity of the system, the laser energy is better harvested by the carbon microparticles, improving the fabrication efficiency a 15% and enhancing the fluorescence of CQDs by an order of magnitude in comparison with the conventional batch. The flow jet-synthesized CQDs have a mean size of 3 nm and are used for fluorescent imaging of transparent healthy and cancer epithelial human cells. Complete internalization is observed with a short incubation time of 10 min without using any extra additive or processing of the cell culture. The CQDs are well fixed in the organelles of the cell even after its death; hence, this is a simple manner to keep the cell information for prolonged periods of time. Moreover, the integrated photostability of the CQDs internalized in in vitro cells is measured and it remains almost constant during at least 2 h, revealing their outstanding performance as fluorescent labels.

Selenium-coated nanostructured lipid carriers used for oral delivery of berberine to accomplish a synergic hypoglycemic effect

Diabetes mellitus is an incurable metabolic disorder that seriously threatens human health. At present, there is no effective medication available to defeat it. This work intended to develop selenium-coated nanostructured lipid carriers (SeNLCs) for enhancing the oral bioavailability and the curative effect of berberine, an antidiabetic phytomedicine. Berberine-loaded SeNLCs (BB-SeNLCs) were prepared by hot-melt dispersion/homogenization procedure followed by in situ reduction. BB-SeNLCs were characterized by particle size, morphology, entrapment efficiency (EE) and in vitro release. Pharmacokinetics of berberine solution, berberine-loaded NLCs (BB-NLCs) and BB-SeNLCs were studied in Sprague Dawley rats administered by oral gavage. The prepared BB-SeNLCs were around 160 nm in particle size with an EE of 90%. In addition, BB-SeNLCs exhibited a better sustained release of berberine compared to the plain NLCs. After oral administration, BB-SeNLCs greatly enhanced the oral bioavailability of berberine, which was approximately 6.63 times as much as that of berberine solution. The hypoglycemic effect of BB-SeNLCs was also significantly superior to that of BB-NLCs and berberine solution. It turned out that sustained drug release and good intestinal absorption, plus the synergy of selenium, were basically responsible for enhanced oral bioavailability and hypoglycemic effect. Our findings show that SeNLCs are promising nanocarriers for oral delivery of berberine to strengthen the antidiabetic action.