Silver colloids as plasmonic substrates for direct label-free surface-enhanced Raman scattering analysis of DNA

Ultrasensitive direct SERS analysis offers a powerful analytical tool for the structural characterization and classification of nucleic acids. However, acquisition of reliable spectral fingerprints of such complex biomolecules poses important challenges. In recent years, many efforts have been devoted to overcome these limitations, mainly implementing silver colloids as plasmonic substrates. However, a reliable cross-comparison of results reported in the recent literature is extremely hard to achieve, mostly due to the broad set of different surface properties of the plasmonic nanoparticles. Herein, we perform a thorough investigation of the role played by the metal/liquid interface composition of silver colloids in the direct label-free SERS analysis of DNA. Target molecules of increasing complexity, from short homopolymeric strands to long genomic duplexes, were used as probes. We demonstrate how apparently subtle changes in the colloidal surface chemistry can dramatically modify the affinity and the final SERS spectral profile of DNA. This has significant implications for the future design of new analytical strategies for the detection of DNA using SERS without labels

Extraordinarily transparent compact metallic metamaterials

The design of achromatic optical components requires materials with high transparency and low dispersion. We show that although metals are highly opaque, densely packed arrays of metallic nanoparticles can be more transparent to infrared radiation than dielectrics such as germanium, even when the arrays are over 75% metal by volume. Such arrays form effective dielectrics that are virtually dispersion-free over ultra-broadband ranges of wavelengths from microns up to millimeters or more. Furthermore, the local refractive indices may be tuned by altering the size, shape, and spacing of the nanoparticles, allowing the design of gradient-index lenses that guide and focus light on the microscale. The electric field is also strongly concentrated in the gaps between the metallic nanoparticles, and the simultaneous focusing and squeezing of the electric field produces strong ‘doubly-enhanced’ hotspots which could boost measurements made using infrared spectroscopy and other non-linear processes over a broad range of frequencies

Spontaneous and stimulated electron–photon interactions in nanoscale plasmonic near fields

The interplay between free electrons, light, and matter offers unique prospects for space, time, and energy resolved optical material characterization, structured light generation, and quantum information processing. Here, we study the nanoscale features of spontaneous and stimulated electron–photon interactions mediated by localized surface plasmon resonances at the tips of a gold nanostar using electron energy-loss spectroscopy (EELS), cathodoluminescence spectroscopy (CL), and photon-induced near-field electron microscopy (PINEM). Supported by numerical electromagnetic boundary-element method (BEM) calculations, we show that the different coupling mechanisms probed by EELS, CL, and PINEM feature the same spatial dependence on the electric field distribution of the tip modes. However, the electron–photon interaction strength is found to vary with the incident electron velocity, as determined by the spatial Fourier transform of the electric near-field component parallel to the electron trajectory. For the tightly confined plasmonic tip resonances, our calculations suggest an optimum coupling velocity at electron energies as low as a few keV. Our results are discussed in the context of more complex geometries supporting multiple modes with spatial and spectral overlap. We provide fundamental insights into spontaneous and stimulated electron-light-matter interactions with key implications for research on (quantum) coherent optical phenomena at the nanoscale

Tunable anisotropy in inverse opals and emerging optical properties

Using self-assembly, nanoscale materials can be fabricated from the bottom up. Opals and inverse opals are examples of self-assembled nanomaterials made from crystallizing colloidal particles. As self-assembly requires a high level of control, it is challenging to use building blocks with anisotropic geometry to form complex opals, which limits the realizable structures. Typically, spherical colloids are employed as building blocks, leading to symmetric, isotropic superstructures. However, a significantly richer palette of directionally dependent properties are expected if less symmetric, anisotropic structures can be created, especially originating from the assembly of regular, spherical particles. Here we show a simple method to introduce anisotropy into inverse opals by subjecting them to a post-assembly thermal treatment that results in directional shrinkage of the silica matrix caused by condensation of partially hydrated sol-gel silica structures. In this way, we can tailor the shape of the pores, and the anisotropy of the final inverse opal preserves the order and uniformity of the self-assembled structure, while completely avoiding the need to synthesize complex oval-shaped particles and crystallize them into such target geometries. Detailed X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy studies clearly identify increasing degrees of sol-gel condensation in confinement as a mechanism for the structure change. A computer simulation of structure changes resulting from the condensation-induced shrinkage further confirmed this mechanism. As an example of property changes induced by the introduction of anisotropy, we characterized the optical spectra of the anisotropic inverse opals and found that the optical properties can be controlled in a precise way using calcination temperature

Molecular dynamics simulation of humic substances

© 2014, Orsi. Humic substances (HS) are complex mixtures of natural organic material which are found almost everywhere in the environment, and particularly in soils, sediments, and natural water. HS play key roles in many processes of paramount importance, such as plant growth, carbon storage, and the fate of contaminants in the environment. While most of the research on HS has been traditionally carried out by conventional experimental approaches, over the past 20 years complementary investigations have emerged from the application of computer modeling and simulation techniques. This paper reviews the literature regarding computational studies of HS, with a specific focus on molecular dynamics simulations. Significant achievements, outstanding issues, and future prospects are summarized and discussed

Silicon particles as trojan horses for potential cancer therapy

[EN] Background: Porous silicon particles (PSiPs) have been used extensively as drug delivery systems, loaded with chemical species for disease treatment. It is well known from silicon producers that silicon is characterized by a low reduction potential, which in the case of PSiPs promotes explosive oxidation reactions with energy yields exceeding that of trinitrotoluene (TNT). The functionalization of the silica layer with sugars prevents its solubilization, while further functionalization with an appropriate antibody enables increased bioaccumulation inside selected cells. Results: We present here an immunotherapy approach for potential cancer treatment. Our platform comprises the use of engineered silicon particles conjugated with a selective antibody. The conceptual advantage of our system is that after reaction, the particles are degraded into soluble and excretable biocomponents. Conclusions: In our study, we demonstrate in particular, specific targeting and destruction of cancer cells in vitro. The fact that the LD50 value of PSiPs-HER-2 for tumor cells was 15-fold lower than the LD50 value for control cells demonstrates very high in vitro specificity. This is the first important step on a long road towards the design and development of novel chemotherapeutic agents against cancer in general, and breast cancer in particular.The authors acknowledge financial support from the following projects FIS2009-07812, MAT2012-35040, PROMETEO/2010/043, CTQ2011-23167, CrossSERS, FP7 MC-IEF 329131, and HSFP (project RGP0052/2012) and Medcom Tech SA. Xiang Yu acknowledges support by the Chinese government (CSC, Nr. 2010691036).Fenollosa Esteve, R.; Garcia-Rico, E.; Alvarez, S.; Alvarez, R.; Yu, X.; Rodriguez, I.; Carregal-Romero, S.... (2014). Silicon particles as trojan horses for potential cancer therapy. Journal of Nanobiotechnology. 12:1-10. https://doi.org/10.1186/s12951-014-0035-7S11012Prasad PN: Introduction to Nanomedicine and Nanobioengineering. Wiley, New York, 2012.Randall CL, Leong TG, Bassik N, Gracias DH: 3D lithographically fabricated nanoliter containers for drug delivery. Adv Drug Del Rev. 2007, 59: 1547-1561. 10.1016/j.addr.2007.08.024.Reibetanz U, Chen MHA, Mutukumaraswamy S, Liaw ZY, Oh BHL, Venkatraman S, Donath E, Neu BR: Colloidal DNA carriers for direct localization in cell compartments by pH sensoring. Biogeosciences. 2010, 11: 1779-1784.Tasciotti E, Liu X, Bhavane R, Plant K, Leonard AD, Price BK, Cheng MM-C, Decuzzi P, Tour JM, Robertson F, Ferrari M: Mesoporous silicon particles as a multistage delivery system for imaging and therapeutic applications. Nat Nano. 2008, 3: 151-157. 10.1038/nnano.2008.34.Park J-H, Gu L, von Maltzahn G, Ruoslahti E, Bhatia SN, Sailor MJ: Biodegradable luminescent porous silicon nanoparticles for in vivo applications. Nat Mater. 2009, 8: 331-336. 10.1038/nmat2398.Hong C, Lee J, Son M, Hong SS, Lee C: In-vivo cancer cell destruction using porous silicon nanoparticles. Anti-Cancer Drugs. 2011, 22: 971-977. 910.1097/CAD.1090b1013e32834b32859cCanham LT: Device Comprising Resorbable Silicon for Boron Capture Neutron Therapy. UK Patent Nr. 0302283.7. Book Device Comprising Resorbable Silicon for Boron Capture Neutron Therapy. UK Patent Nr. 0302283.7 (Editor ed.^eds.). 2003, UK Patent Nr. 0302283.7, CityXiao L, Gu L, Howell SB, Sailor MJ: Porous silicon nanoparticle photosensitizers for singlet oxygen and their phototoxicity against cancer cells. ACS Nano. 2011, 5: 3651-3659. 10.1021/nn1035262.Gil PR, Parak WJ: Composite nanoparticles take Aim at cancer. ACS Nano. 2008, 2: 2200-2205. 10.1021/nn800716j.Gomella LG: Is interstitial hyperthermia a safe and efficacious adjunct to radiotherapy for localized prostate cancer?. Nat Clin Pract Urol. 2004, 1: 72-73. 10.1038/ncpuro0041.Maier-Hauff K, Ulrich F, Nestler D, Niehoff H, Wust P, Thiesen B, Orawa H, Budach V, Jordan A: Efficacy and safety of intratumoral thermotherapy using magnetic iron-oxide nanoparticles combined with external beam radiotherapy on patients with recurrent glioblastoma multiforme. J Neuro-Oncol. 2011, 103: 317-324. 10.1007/s11060-010-0389-0.Lal S, Clare SE, Halas NJ: Nanoshell-enabled photothermal cancer therapy: Impending clinical impact. Acc Chem Res. 2008, 41: 1842-1851. 10.1021/ar800150g.Lee C, Kim H, Hong C, Kim M, Hong SS, Lee DH, Lee WI: Porous silicon as an agent for cancer thermotherapy based on near-infrared light irradiation. J Mater Chem. 2008, 18: 4790-4795. 10.1039/b808500e.Osminkina LA, Gongalsky MB, Motuzuk AV, Timoshenko VY, Kudryavtsev AA: Silicon nanocrystals as photo- and sono-sensitizers for biomedical applications. Appl Phys B. 2011, 105: 665-668. 10.1007/s00340-011-4562-8.Jain PK, Huang X, El-Sayed IH, El-Sayed MA: Noble metals on the nanoscale: optical and photothermal properties and some applications in imaging, sensing, biology, and medicine. Acc Chem Res. 2008, 41: 1578-1586. 10.1021/ar7002804.Serda RE, Godin B, Blanco E, Chiappini C, Ferrari M: Multi-stage delivery nano-particle systems for therapeutic applications. Biochim Biophys Acta. 1810, 2011: 317-329.Xu R, Huang Y, Mai J, Zhang G, Guo X, Xia X, Koay EJ, Qin G, Erm DR, Li Q, Liu X, Ferrari M, Shen H: Multistage vectored siRNA targeting ataxia-telangiectasia mutated for breast cancer therapy. Small. 2013, 9: 1799-1808. 10.1002/smll.201201510.Park JS, Kinsella JM, Jandial DD, Howell SB, Sailor MJ: Cisplatin-loaded porous Si microparticles capped by electroless deposition of platinum. Small. 2011, 7: 2061-2069. 10.1002/smll.201100438.Xue M, Zhong X, Shaposhnik Z, Qu Y, Tamanoi F, Duan X, Zink JI: pH-operated mechanized porous silicon nanoparticles. J Am Chem Soc. 2011, 133: 8798-8801. 10.1021/ja201252e.Canham LT: Bioactive silicon structure fabrication through nanoetching techniques. Adv Mater. 1995, 7: 1033-1037. 10.1002/adma.19950071215.Popplewell JF, King SJ, Day JP, Ackrill P, Fifield LK, Cresswell RG, Di Tada ML, Liu K: Kinetics of uptake and elimination of silicic acid by a human subject: a novel application of 32Si and accelerator mass spectrometry. J Inorganic Biochem. 1998, 69: 177-180. 10.1016/S0162-0134(97)10016-2.Shabir Q, Pokale A, Loni A, Johnson DR, Canham LT, Fenollosa R, Tymczenko M, Rodr guez I, Meseguer F, Cros A, Cantarero A: Medically biodegradable hydrogenated amorphous silicon microspheres. Silicon. 2011, 3: 173-176. 10.1007/s12633-011-9097-4.Chen Y, Wan Y, Wang Y, Zhang H, Jiao Z: Anticancer efficacy enhancement and attenuation of side effects of doxorubicin with titanium dioxide nanoparticles. Int J Nanomed. 2011, 6: 2321-2326.Mackowiak SA, Schmidt A, Weiss V, Argyo C, von Schirnding C, Bein T, Bräuchle C: Targeted drug delivery in cancer cells with Red-light photoactivated mesoporous silica nanoparticles. Nano Lett. 2013, 13: 2576-2583. 10.1021/nl400681f.Li Z, Barnes JC, Bosoy A, Stoddart JF, Zink JI: Mesoporous silica nanoparticles in biomedical applications. Chem Soc Rev. 2012, 41: 2590-2605. 10.1039/c1cs15246g.O Mara WC, Herring B, Hunt P: Handbook of Semiconductor Silicon Technology. Noyes Publication, New Jersey, 1990.Mikulec FV, Kirtland JD, Sailor MJ: Explosive nanocrystalline porous silicon and its Use in atomic emission spectroscopy. Adv Mater. 2002, 14: 38-41. 10.1002/1521-4095(20020104)14:13.0.CO;2-Z.Clement D, Diener J, Gross E, Kunzner N, Timoshenko VY, Kovalev D: Highly explosive nanosilicon-based composite materials. Phys Stat Sol A. 2005, 202: 1357-1359. 10.1002/pssa.200461102.Canham LT: Silicon quantum wire array fabrication by electrochemical and chemical dissolution of wafers. Appl Phys Lett. 1990, 57: 1046-1049. 10.1063/1.103561.Canham LT: Properties of Porous Silicon. INSPEC, United Kindom, 1997.Heinrich JL, Curtis CL, Credo GM, Sailor MJ, Kavanagh KL: Luminescent colloidal silicon suspensions from porous silicon. Science. 1992, 255: 66-68. 10.1126/science.255.5040.66.Littau KA, Szajowski PJ, Muller AJ, Kortan AR, Brus LE: A luminescent silicon nanocrystal colloid via a high-temperature aerosol reaction. J Phys Chem. 1993, 97: 1224-1230. 10.1021/j100108a019.Menz WJ, Shekar S, Brownbridge GPE, Mosbach S, Kōrmer R, Peukert W, Kraft M: Synthesis of silicon nanoparticles with a narrow size distribution: a theoretical study. J Aerosol Sci. 2012, 44: 46-61. 10.1016/j.jaerosci.2011.10.005.Swihart MT, Girshick SL: Thermochemistry and kinetics of silicon hydride cluster formation during thermal decomposition of silane. J Phys Chem B. 1998, 103: 64-76. 10.1021/jp983358e.Fenollosa R, Ramiro-Manzano F, Tymczenko M, Meseguer F: Porous silicon microspheres: synthesis, characterization and application to photonic microcavities. J Mater Chem. 2010, 20: 5210-5214. 10.1039/c0jm00079e.Ramiro-Manzano F, Fenollosa R, Xifré-Pérez E, Garín M, Meseguer F: Porous silicon microcavities based photonic barcodes. Adv Mater. 2011, 23: 3022-3025. 10.1002/adma.201100986.Kastl L, Sasse D, Wulf V, Hartmann R, Mircheski J, Ranke C, Carregal-Romero S, Martínez-López JA, Fernández-Chacón R, Parak WJ, Elsasser HP, Rivera-Gil P: Multiple internalization pathways of polyelectrolyte multilayer capsules into mammalian cells. ACS Nano. 2013, 7: 6605-6618. 10.1021/nn306032k.Schweiger C, Hartmann R, Zhang F, Parak W, Kissel T, Rivera_Gil P: Quantification of the internalization patterns of superparamagnetic iron oxide nanoparticles with opposite charge. J Nanobiotech. 2012, 10: 28-10.1186/1477-3155-10-28.Sanles-Sobrido M, Exner W, Rodr guez-Lorenzo L, Rodríguez-Gonzílez B, Correa-Duarte MA, Álvarez-Puebla RA, Liz-Marzán LM: Design of SERS-encoded, submicron, hollow particles through confined growth of encapsulated metal nanoparticles. J Am Chem Soc. 2009, 131: 2699-2705. 10.1021/ja8088444.Slamon D, Eiermann W, Robert N, Pienkowski T, Martin M, Press M, Mackey J, Glaspy J, Chan A, Pawlicki M, Pinter T, Valero V, Liu MC, Sauter G, von Minckwitz G, Visco F, Bee V, Buyse M, Bendahmane B, Tabah-Fisch I, Lindsay MA, Riva A, Crown J: Adjuvant trastuzumab in HER2-positive breast cancer. N Engl J Med. 2011, 365: 1273-1283. 10.1056/NEJMoa0910383.Agus DB, Gordon MS, Taylor C, Natale RB, Karlan B, Mendelson DS, Press MF, Allison DE, Sliwkowski MX, Lieberman G, Kelsey SM, Fyfe G: Phase I clinical study of pertuzumab, a novel HER dimerization inhibitor, in patients with advanced cancer. J Clin Oncol. 2005, 23: 2534-2543. 10.1200/JCO.2005.03.184.Colombo M, Mazzucchelli S, Montenegro JM, Galbiati E, Corsi F, Parak WJ, Prosperi D: Protein oriented ligation on nanoparticles exploiting O6-alkylguanine-DNA transferase (SNAP) genetically encoded fusion. Small. 2012, 8: 1492-1497. 10.1002/smll.201102284.Franklin MC, Carey KD, Vajdos FF, Leahy DJ, de Vos AM, Sliwkowski MX: Insights into ErbB signaling from the structure of the ErbB2-pertuzumab complex. Cancer Cell. 2004, 5: 317-328. 10.1016/S1535-6108(04)00083-2.Paris L, Cecchetti S, Spadaro F, Abalsamo L, Lugini L, Pisanu ME, Lorio E, Natali PG, Ramoni C, Podo F: Inhibition of phosphatidylcholine-specific phospholipase C downregulates HER2 overexpression on plasma membrane of breast cancer cells. Breast Cancer Res. 2010, 12: R27-10.1186/bcr2575.Fenollosa R, Meseguer F, Tymczenko M: Silicon colloids: from microcavities to photonic sponges. Adv Mater. 2008, 20: 95-98. 10.1002/adma.200701589.Jasinski JM, Gates SM: Silicon chemical vapor deposition one step at a time: fundamental studies of silicon hydride chemistry. Acc Chem Res. 1991, 24: 9-15. 10.1021/ar00001a002.Xiao Q, Liu Y, Qiu Y, Zhou G, Mao C, Li Z, Yao Z-J, Jiang S: Potent antitumor mimetics of annonaceous acetogenins embedded with an aromatic moiety in the left hydrocarbon chain part. J Med Chem. 2010, 54: 525-533. 10.1021/jm101053k.Allman SA, Jensen HH, Vijayakrishnan B, Garnett JA, Leon E, Liu Y, Anthony DC, Sibson NR, Feizi T, Matthews S, Davis BG: Potent fluoro-oligosaccharide probes of adhesion in toxoplasmosis. ChemBioChem. 2009, 10: 2522-2529. 10.1002/cbic.200900425.Chambers DJ, Evans GR, Fairbanks AJ: Elimination reactions of glycosyl selenoxides. Tetrahedron. 2004, 60: 8411-8419. 10.1016/j.tet.2004.07.005.Tomabechi Y, Suzuki R, Haneda K, Inazu T: Chemo-enzymatic synthesis of glycosylated insulin using a GlcNAc tag. Bioorg Med Chem. 2010, 18: 1259-1264. 10.1016/j.bmc.2009.12.031.Pastoriza-Santos I, Gomez D, Perez-Juste J, Liz-Marzan LM, Mulvaney P: Optical properties of metal nanoparticle coated silica spheres: a simple effective medium approach. Phys Chem Chem Phys. 2004, 6: 5056-5060. 10.1039/b405157b

Optical Nanoantennas for Multiband Surface-Enhanced Infrared and Raman Spectroscopy

n/

Diverse Applications of Nanomedicine

The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic. \ua9 2017 American Chemical Society