Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

Magnetic Nanoparticles in MR Imaging and Drug Delivery

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Functional Nucleic Acid Sensors

Biocompatibility, Pharmaceutical and Biomedical Applications L. Harivardhan Reddy,†,‡ Jose ́ L. Arias, Julien Nicolas,† and Patrick Couvreur*,† †Laboratoire de Physico-Chimie, Pharmacotechnie et Biopharmacie, Universite ́ Paris-Sud XI, UMR CNRS 8612, Faculte ́ de Pharmacie, IFR 141, 5 rue Jean-Baptiste Cleḿent, F-92296 Chat̂enay-Malabry, France Departamento de Farmacia y Tecnología Farmaceútica, Facultad de Farmacia, Campus Universitario de Cartuja s/n, Universidad de Granada, 18071 Granada, Spain ‡Pharmaceutical Sciences Department, Sanofi, 13 Quai Jules Guesdes, F-94403 Vitry-sur-Seine, France

Magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications.

The wide variety of core materials available, coupled with tunable surface properties, make nanoparticles an excellent platform for a broad range of biological and biomedical applications. This Review provides an introduction to nanoparticle–biomolecular interactions as well as recent applications of nanoparticles in biological sensing, delivery, and imaging of live cells and tissues.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.200703183

Applications of Nanoparticles in Biology

We have developed uniform core/shell nanoparticles, consisting of a silica layer coating and pigments or magnetite core, using a water-in-oil microemulsion method. The nanoparticles are highly luminescent and photostable with the size ranging from 5 nm to 400 nm. Bioconjugation of these silica nanoparticles adds unique biofunctions with various molecules such as enzymes, antibodies, and DNA molecules. Significant advantages have been shown in using bioconjugated nanoparticles for biosensing and bioimaging, such as cell staining, DNA detection and separation, rapid single bacterium detection, and biotechnological application in DNA protection.

Bionanotechnology based on silica nanoparticles

Monitoring gene expression is at the center of research for a wide variety of medical, biological, and biotechnological applications. Currently no method exists for true multiple gene expression monitoring inside of a single living cell that allows for the gene expression profile of the cell to be directly compared with another single living cell. By microinjecting multiple molecular beacons with different fluorophores inside of single breast carcinoma cells and monitoring with advanced fluorescent microscopy, the expression of multiple genes can be simultaneously monitored inside single living cells. Using ratiometric analysis as a basis for the measurements allows the different gene expression levels to be compared from cell to cell. Not only does this allow differentiation of individual mRNA expression levels between multiple single cells but it also allows for mRNA expression trend analysis at the single cell level.

Simultaneous Monitoring of the Expression of Multiple Genes Inside of Single Breast Carcinoma Cells

Molecular beacons (MBs) are hairpin-shaped oligonucleotides that contain both fluorophore and quencher moieties. They act like switches and are normally in a closed state, when the fluorophore and the quencher are brought together to turn “off” the fluorescence. When prompted to undergo conformational changes that open the hairpin structure, the fluorophore and the quencher are separated, and fluorescence is turned “on.” This Education will outline the principles of MBs and discuss recent bioanalytical applications of these probes for in vitro RNA and DNA monitoring, biosensors and biochips, real-time monitoring of genes and gene expression in living systems, as well as the next generation of MBs for studies on proteins, the MB aptamers. These important applications have shown that MBs hold great potential in genomics and proteomics where real-time molecular recognition with high sensitivity and excellent specificity is critical.

Molecular beacons for bioanalytical applications

This report describes studies on the use of a molecular-beacon aptamer (MBA) as a synthetic high-affinity DNA probe that exhibits fluorescence resonance energy transfer (FRET) in response to a specific protein biomarker, platelet-derived growth factor (PDGF). As a step toward the application of the MBA in a fluorescence-based assay for biological specimens, we examined the influence of certain physical and chemical parameters of incubation that would affect DNA conformation and DNA-backbone modification, and thus improve nuclease resistance. This bioassay is compatible with pH, temperature, and monovalent cation levels typically encountered in biological samples, and phosphorothioate backbone-modified MBA is able to exhibit specific FRET. With minimal sample processing and without assay optimization, the MBA is able to detect as little as 10 ng PDGF per mug of serum proteins from cell-culture media. We also show that different sets of known fluorophore-quencher pairs can be successfully used in the MBA for sensitive detection of the PDGF target. It should, therefore, be possible to develop multiplex bioassays that monitor either quenching or enhancement for the simultaneous detection of several biomarkers by using MBAs created from high-affinity DNA ligands for the desired protein targets. Interestingly, we observed that, with a DNA ligand with multiple binding sites for a standard multimeric protein target, the FRET bioassay could be accomplished by using a mixture of two individually labeled DNAs-one carrying the fluorophore and the other with the matching quencher. This observation has significant implications in the future design of more selective DNA-based FRET bioassays that use more than one ligand for the same protein target.

Investigation of molecular beacon aptamer-based bioassay for platelet-derived growth factor detection.

In the post-genomic and proteomic era, a continued demand still exists for biomolecular recognition probes with high sensitivity and selectivity for use in quantitative studies of genomic and proteomic information. These are particularly important for disease diagnosis as well as drug discovery.1–4 Since they were first reported in 1996,5 molecular beacons (MBs) have become a class of molecules widely used in chemistry, biology, biotechnology, and medical sciences for biomolecular recognition,3,4,6–8 due in part to their functionality and molecular specificity. In the traditional format, MBs act like switches that are normally closed, or ‘‘off’’. Binding induces conformational changes that open the hairpin and as a result the fluorescence is turned ‘‘on’’. More re-

https://journals.sagepub.com/doi/pdf/10.1366/0003702041959406

Timothy J. Drake

Papers

Bionanotechnology based on silica nanoparticles

Simultaneous Monitoring of the Expression of Multiple Genes Inside of Single Breast Carcinoma Cells

Molecular beacons for bioanalytical applications

Investigation of molecular beacon aptamer-based bioassay for platelet-derived growth factor detection.

Molecular Beacon DNA Probes and Their Bioanalytical Applications