Gold nanorods are promising metals in several biomedical applications such as bioimaging, thermal therapy, and drug delivery. Gold nanorods have strong absorption bands in near-infrared (NIR) light region and show photothermal effects. Since NIR light can penetrate deeply into tissues, their unique optical, chemical, and biological properties have attracted considerable clinical interest. Gold nanorods are expected to act not only as on-demand thermal converters for photothermal therapy but also as mediators of a controlled drug-release system responding to light irradiation. In this review, we discuss current progress using gold nanorods as bioimaging platform, phototherapeutic agents, and drug delivery vehicles.

No abstract

The phase content of a low-density polyethylene was studied by analysis of the CH2 rocking vibrations in non-oriented films prepared from the press (P-films) or from solution (S-films). Spectral simulations of the transmission spectra give the mass fractions of the orthorhombic phase αortho and of two noncrystalline phases (monoclinic-like and amorphous). The values of αortho (IR) are compared to αortho (i) where (i) stands for the X-ray diffraction, density, and DSC techniques. New results are obtained concerning the orthorhombic order and the change of phase content with aging. A two-phase analysis is justified for non-aged films containing a small amount of the monoclinic-like phase. The values of αortho (IR) are larger than αortho (i), the difference ranging between 0.12 and 0.43. The difference is a measure of the short-range order. αortho (IR) can reach 0.73 for the S-films. The stability of the short-range order phase is investigated. The sample is also analyzed using the trace of slow calorimetry. The difference between αortho by DSC and by slow calorimetry is a measure of strainable order. During aging, the variation in the phase content is large for the noncrystalline phases (in content and frequency) and small for the orthorhombic. The increase of the monoclinic-like phase during aging suggests that it is a precursor of the more stable orthorhombic organization. The quantification of two noncrystalline phases on fresh and aged films clarifies some ambiguity found in the literature about the monoclinic-like phase and the localization of bands in the rocking region for sample characterization. Analysis of other regions of the spectrum is needed to confirm the present results. Key words: low-density PE, phase content, FTIR, network phase, slow calorimetry.

Among the several types of nanoparticles in existence, anisotropic gold-based nanoparticles demonstrate special advantages because of their unique properties. Gold nanoparticles can be prepared and modified with a wide range of functional materials including polymers, surfactants, ligands, dendrimers, drugs, DNA, RNA, proteins, peptides, and oligonucleotides. Hence, they are a promising vehicle for bioimaging, drug delivery, and other therapies. This review mainly addresses the properties, preparation, and applications of anisotropic gold nanoparticles in biomedical applications and targeted drug delivery.

No abstract

Gold nanoparticles have been becoming attractive metals in biomedical applications. The unique optical, chemical, and biological properties of gold nanoparticles have supported them for clinical interest in several applications including drug and gene delivery. Gold nanorods have strong absorption bands in the near-infrared region, in which light penetrates deeply into tissues. Hence, gold nanorods are expected to act not only as on-demand thermal converters for photothermal therapy but also as controllers of a drug-release system responding to irradiation by near-infrared light. These attributes can be promoted to provide an effective and selective platform for a targeted intracellular release of some substance. Here we review recent advances in the use of gold nanorods in drug and gene delivery systems.

No abstract

Transdermal protein delivery is a powerful and attractive method for protein therapy and dermal vaccination compared with other administrations. However, this delivery method is restricted by the low permeability of the stratum corneum (SC), a hydrophobic barrier that restricts the entry of hydrophilic molecules such as proteins. In this study, we developed an improved gel patch system carrying ovalbumin and ovalbumin epitope peptide, and then compared their permeability into the skin. First, the gel patch was placed on mouse skin to allow contact with the polymer coated gold nanorods and then irradiated by a continuous-wave laser. Thermal ablation of the SC improved the permeability and translocation of ovalbumin and the peptide. Fluorescence images showed the translocation was enhanced when the skin was treated with the FITC-modified ovalbumin epitope peptide. However, induction of anti-OVA IgG production after treatment with the FITC-modified ovalbumin epitope peptide was lower than that with FITC-OVA.