Measurement of immunotargeted plasmonic nanoparticles' cellular binding: a key factor in optimizing diagnostic efficacy

Plasmonic labeling of subcellular compartments in cancer cells: multiplexing with fine-tuned gold and silver nanoshells

Fine-tuned gold and silver nanoshells were produced via an entirely reformulated synthesis. The new method yielded ultramonodisperse samples, with polydispersity indexes (PI) as low as 0.02 and narrow extinction bands suited for multiplex analysis. A library of nanoshell samples with localized surface plasmon resonances (LSPR) spanning across the visible range was synthesized. Hyperspectral analysis revealed that the average scattering spectrum of 100 nanoshells matched closely to the spectrum of a single nanoshell, indicating an unprecedented low level of nanoparticle-to-nanoparticle variation for this type of system. A cell labeling experiment, targeting different subcellular compartments in MCF-7 human breast cancer cells, demonstrated that these monodisperse nanoparticles can be used as a multiplex platform for single cell analysis at the intracellular and extracellular level. Antibody-coated gold nanoshells targeted the plasma membrane, while silver nanoshells coated with a nuclear localization signal (NLS) targeted the nuclear membrane. A fluorescence counterstaining experiment, as well as single cell hyperspectral microscopy showed the excellent selectivity and specificity of each type of nanoparticle for its designed subcellular compartment. A time-lapse photodegradation experiment confirmed the enhanced stability of the nanoshells over fluorescent labeling and their capabilities for long-term live cell imaging.

Evaluation of Cytotoxic Effects of Different Concentrations of Porous Hollow Au Nanoparticles (PHAuNPs) on Cells

Nanoparticles (NPs) have been introduced as a suitable alternative in manyin vivobioapplications. The risks of utilizing nanoparticles continue to be an ongoing research. Furthermore, the various chemicals used in their synthesis influence the cytotoxic effects of nanoparticles. We have investigated the cytotoxicity of Porous Hollow Au Nanoparticles (PHAuNPs) on cancer cell lines PC-3, PC-3ML, and MDA-MB-231 and the normal cell line PNT1A. Cell proliferation for the different cells in the presence of different concentrations of the PHAuNPs was assessed after 24 hours and 72 hours of incubation using MTT assay. The study also included the cytotoxic evaluation of pegylated PHAuNPs. Identical cell seeding densities, particle concentrations, and incubation times were employed for these two types of Au nanoparticles. Our results indicated that (1) impact on cell proliferation was concentration dependent and was different for the different cell types without cellular necrosis and (b) cellular proliferation might be impacted more based on the cell line.

Gold nanoparticles in biomedical applications: recent advances and perspectives

Gold nanoparticles (GNPs) with controlled geometrical, optical, and surface chemical properties are the subject of intensive studies and applications in biology and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensorics, immunoassays and clinical chemistry, photothermolysis of cancer cells and tumors, targeted delivery of drugs and antigens, and optical bioimaging of cells and tissues with state-of-the-art nanophotonic detection systems. This critical review is focused on the application of GNP conjugates to biomedical diagnostics and analytics, photothermal and photodynamic therapies, and delivery of target molecules. Distinct from other published reviews, we present a summary of the immunological properties of GNPs. For each of the above topics, the basic principles, recent advances, and current challenges are discussed (508 references).

Translational nanomedicine: status assessment and opportunities

Nano-enabled technologies hold great promise for medicine and health. The rapid progress by the physical sciences/engineering communities in synthesizing nanostructures and characterizing their properties must be rapidly exploited in medicine and health toward reducing mortality rate, morbidity an illness imposes on a patient, disease prevalence, and general societal burden. A National Science Foundation-funded workshop, "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience," was held 16-19 March 2008 at the University of Southern California. Based on that workshop and literature review, this article briefly explores scientific, economic, and societal drivers for nanomedicine initiatives; examines the science, engineering, and medical research needs; succinctly reviews the US federal investment directly germane to medicine and health, with brief mention of the European Union (EU) effort; and presents recommendations to accelerate the translation of nano-enabled technologies from laboratory discovery into clinical practice.

FROM THE CLINICAL EDITOR

An excellent review paper based on the NSF funded workshop "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience" (16-19 March 2008) and extensive literature search, this paper briefly explores the current state and future perspectives of nanomedicine.

Computer modeling of the optical properties and heating of spherical gold and silica-gold nanoparticles for laser combined imaging and photothermal treatment

Recently, several groups of investigators (Anderson, Halas, Zharov, El-Sayed and their co-workers (Pitsillides et al 2003 Biophys. J. 84 4023-31, Zharov et al 2003 Appl. Phys. Lett. 83 4897-9, Zharov et al 2004 Proc. SPIE 5319 291-9, Loo et al 2005 Nano Lett. 5 709-11, Gobin et al 2007 Nano Lett. 7 1929-34, Fu et al 2008 Nanotechnology 19 045103, Huang et al 2006 J. Am. Chem. Soc. 128 2115-20, Jain et al 2006 J. Phys. Chem. B 110 7238-48, Jain et al 2007 Nano Today 2 18-29)) demonstrated, through pioneering results, the great potential of laser thermal therapy of cells and tissues conjugated with gold nanoparticles. It was also proposed to use combined diagnostics and therapy on the basis of nanoparticle selection for achievement of efficient contrast for laser imaging applications, as well as for photothermal therapy. However, the current understanding of the relationship between optical properties (absorption, backscattering) of nanoparticles, the efficiency of nanoparticle heating and the possibility to use them for combined imaging and therapy is limited. Here, we report the results of computer modeling of optical absorption and backscattering properties and laser heating of gold and silica-gold spherical nanoparticles for laser combined imaging and photothermal treatment of cells and tissues conjugated with nanoparticles. The efficiencies of nanoparticle heating and backscattering by nanoparticles, depending upon their radii, structure and optical properties of the metal, were investigated. This paper focuses on the analysis and determination of appropriate ranges of nanoparticle sizes for the purposes of laser combined imaging and photothermal treatment. The possibility to use spherical gold and silica-gold nanoparticles in determined ranges of radii for these purposes for laser wavelengths 532 and 800 nm is investigated.

Silica-gold nanoshells as potential intraoperative molecular probes for HER2-overexpression in ex vivo breast tissue using near-infrared reflectance confocal microscopy

Obtaining negative margins is critical for breast cancer patients undergoing conservation therapy in order to reduce the reemergence of the original cancer. Currently, breast cancer tumor margins are examined in a pathology lab either while the patient is anesthetized or after the surgical procedure has been terminated. These current methods often result in cancer cells present at the surgical resection margin due to inadequate margin assessment at the point of care. Due to such limitations evident in current diagnoses, tools for increasing the accuracy and speed of tumor margin detection directly in the operating room are still needed. We are exploring the potential of using a nano-biophotonics system to facilitate intraoperative tumor margin assessment ex vivo at the cellular level. By combining bioconjugated silica-based gold nanoshells, which scatter light in the near-infrared, with a portable FDA-approved reflectance confocal microscope, we first validate the use of gold nanoshells as effective reflectance-based imaging probes by evaluating the contrast enhancement of three different HER2-overexpressing cell lines. Additionally, we demonstrate the ability to detect HER2-overexpressing cells in human tissue sections within 5 min of incubation time. This work supports the use of targeted silica-based gold nanoshells as potential real-time molecular probes for HER2-overexpression in human tissue.

Enhanced multi-spectral imaging of live breast cancer cells using immunotargeted gold nanoshells and two-photon excitation microscopy

We demonstrate the capability of using immunotargeted gold nanoshells as contrast agents for in vitro two-photon microscopy. The two-photon luminescence properties of different-sized gold nanoshells are first validated using near-infrared excitation at 780 nm. The utility of two-photon microscopy as a tool for imaging live HER2-overexpressing breast cancer cells labeled with anti-HER2-conjugated nanoshells is then explored and imaging results are compared to normal breast cells. Five different imaging channels are simultaneously examined within the emission wavelength range of 451-644 nm. Our results indicate that under near-infrared excitation, superior contrast of SK-BR-3 cancer cells labeled with immunotargeted nanoshells occurs at an emission wavelength ranging from 590 to 644 nm. Luminescence from labeled normal breast cells and autofluorescence from unlabeled cancer and normal cells remain imperceptible under the same conditions.