Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of ‘gilding the (nanomedicinal) lily’, but that a new ‘Golden Age’ of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).

The golden age: gold nanoparticles for biomedicine

Gold colloids have fascinated scientists for over a century and are now heavily utilized in chemistry, biology, engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chemical functional groups, and, in certain cases, characterized with atomic-level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene-regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to molecule-based systems, but rather for their new physical and chemical properties, which confer substantive advantages in cellular and medical applications.

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Gold nanoparticles for biology and medicine.

Eating five servings of fruits and vegetables per day! This is what is highly recommended and heavily advertised nowadays to the general public to stay fit and healthy! Drinking green tea on a regular basis, eating chocolate from time to time, as well as savoring a couple of glasses of red wine per day have been claimed to increase life expectancy even further! Why? The answer is in fact still under scientific scrutiny, but a particular class of compounds naturally occurring in fruits and vegetables is considered to be crucial for the expression of such human health benefits: the polyphenols! What are these plant products really? What are their physicochemical properties? How do they express their biological activity? Are they really valuable for disease prevention? Can they be used to develop new pharmaceutical drugs? What recent progress has been made toward their preparation by organic synthesis? This Review gives answers from a chemical perspective, summarizes the state of the art, and highlights the most significant advances in the field of polyphenol research.

Plant Polyphenols: Chemical Properties, Biological Activities, and Synthesis

The regulation of engineered nanoparticles requires a widely agreed definition of such particles. Nanoparticles are routinely defined as particles with sizes between about 1 and 100 nm that show properties that are not found in bulk samples of the same material. Here we argue that evidence for novel size-dependent properties alone, rather than particle size, should be the primary criterion in any definition of nanoparticles when making decisions about their regulation for environmental, health and safety reasons. We review the size-dependent properties of a variety of inorganic nanoparticles and find that particles larger than about 30 nm do not in general show properties that would require regulatory scrutiny beyond that required for their bulk counterparts.

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Towards a definition of inorganic nanoparticles from an environmental, health and safety perspective

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Gold nanoparticles functionalized with water-soluble zwitterionic ligands form kinetically stable complexes with hydrophobic drugs and dyes. These drugs and dyes are efficiently released into cells, as demonstrated through fluorescence microscopy and cytotoxicity assays. Significantly, there is little or no cellular uptake of particle, making these low toxicity particles promising for delivery applications.

https://works.bepress.com/vincent_rotello/5/download/

Entrapment of Hydrophobic Drugs in Nanoparticle Monolayers with Efficient Release into Cancer Cells

We extracted, purified and characterized 8 sesquiterpene fractions from Commyphora molmol. In particular, we focused our attention on a mixture of furanodiene-6-one and methoxyfuranoguaia-9-ene-8-one, which showed antibacterial and antifungal activity against standard pathogenic strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, with minimum inhibitory concentrations ranging from 0.18 to 2.8 micrograms/ml. These compounds also had local anaesthetic activity, blocking the inward sodium current of excitable mammalian membranes.

Local anaesthetic, antibacterial and antifungal properties of sesquiterpenes from myrrh.

Analgesic effects of myrrh

Electron spin resonance (ESR), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and scanning tunneling microscopy (STM) have been used in parallel to characterize the deposition on gold surface of a series of nitronyl nitroxide radicals. These compounds have been specifically synthesized with methyl-thio linking groups suitable to interact with the gold surface to form self-assembled monolayers (SAMs), which can be considered relevant in the research for molecular-based spintronics devices, as suggested in recent papers. The degree of the expected ordering on the surface of these SAMs has been tuned by varying the chemical structure of synthesized radicals. ToF-SIMS has been used to support the evidence of the occurrence of the deposition process. STM has shown the different qualities of the obtained SAMs, with the degree of local order increasing as the degree of freedom of the molecules on the surface is decreased. Finally, ESR has confirmed that the deposition process does not affect the paramagnetic characteristics of radicals and that it affords a complete single-layered coverage of the surface. Further, the absence of angular dependence in the spectra indicates that the small regions of local ordering do not give rise to a long-range order and suggests a quite large mobility of the radical on the surface, probably due to the weak interaction with gold provided by the methyl-thio linking group.

Self-assembled organic radicals on Au(111) surfaces: a combined ToF-SIMS, STM, and ESR study.

The Orciatico (ORC) and Montecatini Val di Cecina (MVC) volcanics are composed by plagioclase-free lamproitic assemblages, containing abundant phlogopite, sanidine, clinopyroxene, olivine and apatite, as well as minor ilmenite, magnesio-chromite, K-richterite. A few differentiated samples contain thorite, zircon and perierite. The ORC and MVC rocks are characterized by enrichment in silica (56-59%), incompatible elements and radiogenic Sr as well as high Mg-values (72-76), Ni (150-250 ppm) and Cr (350-450 ppm) abundances. By contrast, they show relatively low Al 2 O 3 (10-12%), CaO (3-4%) and Na 2 O (1-1/5%) contents. Based on the chemical composition of both minerals and rocks, the ORC products were crystallized from mantle-derived magmas, which appear to be more primitive than the MVC volcanics. Moreover, the most primitive ORC magmatic rocks probably did not undergo any differentiative processes during their uprise to the surface from the source region. The MVC parental magma was likely derived from the ORC magma by means of Assimilation+Fractional Crystallization (AFC) processes. After its formation and initial crystallization, the MVC parental magma rose in the form of a crystal mush. The origin of the leucocratic veins and ocelli can be explained by rifting of the lower portion of the MVC crystal mush, and squeezing out of the residual melt that migrated into the early formed cracks. This process was probably triggered by the subsequent emplacement to shallow depths of the MVC crystal mush. The presence of winding leucocratic veins and ocelli in the higher portion of the body is probably due to the lower viscosity of this portion of the crystal mush because of its enrichment in volatiles. The most primitive member of the ultrapotassic magmatic suite in South Tuscany (i.e. ORC) nevertheless have high 87 Sr/ 86 Sr and low 143 Nd/ 144 Nd isotopic ratios as well as very high incompatible elements contents. It is suggested that magma genesis occurred in a mantle source enriched in incompatible elements and radiogenic isotopes. The proposed mantle source composition was depleted in basaltic components some time before the occurrence of the enrichment. The close similarity between the incompatible element abundance pattern of these rocks and that of the most primitive rocks of the Roman Comagmatic Province and Spanish regions, suggests a common origin for the metasomatizing agents that affected the source regions of the Western Mediterranean alkaline magmatic province

Stefano Menichetti

Papers

Entrapment of Hydrophobic Drugs in Nanoparticle Monolayers with Efficient Release into Cancer Cells

Local anaesthetic, antibacterial and antifungal properties of sesquiterpenes from myrrh.

Analgesic effects of myrrh

Self-assembled organic radicals on Au(111) surfaces: a combined ToF-SIMS, STM, and ESR study.

Mineralogy, geochemistry and Sr-isotopes in orendites from South Tuscany, Italy; constraints on their genesis and evolution