Search Results (6)

Atomically precise noble metal nanoclusters protected by ligands are broadly discussed in the literature as a promising new class of materials with many interesting properties. Of those, the most prominent is the characteristic luminescence in the visible and near-infrared light. Within the plethora of conjugates of metal nanoclusters to various protective ligands, protein-enveloped systems present several unique features arising from an interplay of the nanocluster photophysics and the protein chemistry along its macromolecular dynamics. The specific properties of protein–metal nanocluster conjugates underlie various applications of these systems, especially in bioimaging. This review, in contrast to many already published, focuses on protein-protected gold nanoclusters (AuNCs) from the standpoint of the proteinaceous shell which plays a crucial role in the biocompatibility, solubility, and excellent in-solution stability of such nanohybrid complexes. Factors such as the protein’s size, structural rigidity, amino acid composition, electric charge, and the electron donor properties of composite amino acids are discussed. Full article

Photopharmacology is a booming research area requiring a new generation of agents possessing simultaneous functions of photoswitching and pharmacophore. It is important that any practical implementation of photopharmacology ideally requires spatial control of the medicinal treatment zone. Thus, advances in the study of substances meeting all the listed requirements will lead to breakthrough research in the coming years. In this study, CQDs@phosphonate nanohybrids are presented for the first time and combine biocompatible and nontoxic luminescent carbon quantum dots (CQDs) with photoactive phosphonate enabling inhibition of butyrylcholinesterase (BChE), which is a prognostic marker of numerous diseases. The conjunction of these components in hybrids maintains photoswitching and provides enhancement of BChE inhibition. After laser irradiation with a wavelength of 266 nm, CQDs@phosphonate hybrids demonstrate a drastic increase of butyrylcholinesterase inhibition from 38% up to almost 100% and a simultaneous luminescence decrease. All the listed hybrid properties are demonstrated not only for in vitro experiments but also for complex biological samples, i.e., chicken breast. Thus, the most important achievement is the demonstration of hybrids characterized by a remarkable combination of all-in-one properties important for photopharmacology: (i) bioactivity toward butyrylcholinesterase inhibition, (ii) strong change of inhibition degree as a result of laser irradiation, luminescence as an indicator of (iii) bioactivity state, and of (iv) spatial localization on the surface of a sample. Full article

The use of proteins as biomolecular templates to synthesize atomically precise metal nanoclusters has been gaining traction due to their appealing properties such as photoluminescence, good colloidal- and photostability and biocompatibility. The synergistic effect of using a protein scaffold and metal nanoclusters makes it especially attractive for biomedical applications. Unlike other reviews, we focus on proteins in general as the protective ligand for various metal nanoclusters and highlight their applications in the biomedical field. We first introduce the approaches and underlined principles in synthesizing protein-templated metal nanoclusters and summarize some of the typical proteins that have been used thus far. Afterwards, we highlight the key physicochemical properties and the characterization techniques commonly used for the size, structure and optical properties of protein-templated metal nanoclusters. We feature two case studies to illustrate the importance of combining these characterization techniques to elucidate the formation process of protein-templated metal nanoclusters. Lastly, we highlight the promising applications of protein-templated metal nanoclusters in three areas—biosensing, diagnostics and therapeutics. Full article

Nanohybrids, composed of luminescent zinc oxide (ZnO) nanoparticles dispersed in an inert polydimethylsiloxane (PDMS) matrix, exhibit an excellent ability to follow changes in the type and composition of their surrounding atmosphere. These changes are found to affect the UV photoluminescence (PL) emission of the ZnO-PDMS hybrids measured at room temperature. The influence of irradiation parameters, such as excitation intensity and wavelength, on the response of the ZnO-PDMS sensor against ethanol and oxygen, have been systematically investigated in a comparative study performed employing pulsed excitation at 248 and 355 nm. This study represents the first demonstration that the sensing performance of the PL-based ZnO sensors can be optimized by tuning the excitation parameters and it particularly illustrates that maintaining a low pump energy density is crucial for enhancing the sensitivity of the sensor achieving response values approaching 100%. Full article

Mesoporous silica nanoparticles prepared by organic template-driven synthesis have been successfully explored as carriers of the drug-derivate green luminescent complex of terbium (III) with the nonsteroidal anti-inflammatory drug ketoprofen. The terbium (III) complex was synthesized by reacting ketoprofen sodium salt with terbium (III) chloride, which was further adsorbed onto the surface of mesoporous nanoparticles with a mean particle size of 47 ± 4 nm and pore size of 11 nm. The incorporation of the complex into mesoporous silica nanoparticles was tracked by the decrease in the surface area and pore size of the nanoparticles, and successfully demonstrated by substantial changes in the adsorption isotherms and thermal and vibrational spectroscopy results. The cytotoxicity assay and confocal microscopy have shown that the novel luminescent nanohybrid presents high cell viability and the characteristic terbium (III) emission can be assessed through two-photon excitation, which paves the way for bioimaging applications in nanomedicine. Full article

Emphasis using phototheranostics has been placed on the construction of multifunctional nanoplatforms for simultaneous tumor diagnosis and therapy. Herein, we put forth a novel nanosized luminescent material using the incorporation of red emissive carbon dots on gold nanorods through polyethylene glycol as a covalent linkage for dual-modal imaging and photothermal therapy. The novel nanohybrids, not only retain the optical properties of the gold nanorod and carbon dots, but also possess superior imaging performance in both confocal laser scanning microscopy and fluorescence lifetime imaging microscopy. The nanohybrids also exhibit excellent photothermal performance as phototheranostic nanohybrid probes for in vitro assays. This study promises a new multifunctional nanoplatform for cancer diagnostics and therapeutics. Full article