This PDF file contains the front matter associated with SPIE Proceedings Volume 8955, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

A fast and easy method for water transfer of iron oxide nanoparticle based on the hydrophobic interaction of oleic acid coated nanoparticles with the amphiphilic PAMAM-C12 dendrimer is described. The process may be conveniently performed in water and yields nanoparticles with good size distribution, diameter modulation and high crystallinity. The nanoparticles have been functionalized with gadolinium ions to obtain T₁/T₂ dual mode contrast agents. Furthermore, the possibility to deliver and release lipophilic drugs was investigated.

DNA-coated gold nanoparticles are one of the most researched nano-bio hybrid systems. Traditionally their synthesis has been a long and tedious process, involving slow salt addition and long incubation steps. This stems from the fact that both DNA and gold particles are negatively charged, therefore efficient interaction is possible only at high salt concentration. However, unmodified particles are susceptible to aggregation at high salt concentrations. Most of the recent modification methods involve the use of surfactants or other small molecules to stabilize the nanoparticles against aggregation, enabling faster modification. Here we present our result on an alternative route to reach fast modification in low salt conditions, namely, reduction of the charge of DNA. We will discuss both the use of natural DNA under acidic pH conditions, and the use of DNA with a cationic, spermine-based “tail” which is commercially available under the name ZNA. Additionally we introduce a characterization method based on ensemble localized surface plasmon resonance measurement (LSPR) which enabled us to extract the kinetics of DNA absorbance without the need for fluorescent tags. Lastly we show that the same ZNA-based modification protocol can be effectively used for silver nanoparticle modification.

The present work reveals the structural and magnetic properties of iron oxide (Fe_xO_y) nanoparticles (NPs) prepared by femtosecond laser ablation. The Fe_xO_y-NPs were produced in solutions consisting of different ratios of water and acetone. Laser ablation in water yields agglomerates and that in acetone yields chain structures whereas that in water/acetone show a mixture of both. We observe significant fabrication dependent properties such as different crystallinities and magnetic behaviors. The structural characterization shows a change from iron (Fe) to a Fe_xO_y state of the NPs which depends on the solution composition. Furthermore, transmission electron microscopy measurements exhibit a broad particle size distribution in all samples but with significant differences in the mean sizes. Using magnetic measurements we show that nanoparticles fabricated in pure acetone have lower coercive fields which come along with a smaller mean particle size and therefore increasing superparamagnetic behavior.

We prepared a set of multi-coordinating and reactive amphiphilic polymer ligands and used them for surface-functionalizing magnetic iron oxide nanoparticles. The amphiphilic oligomers were prepared by coupling (via one step nucleophilic addition) several dopamine anchoring groups, polyethylene glycol moieties and reactive groups onto a poly(isobutylene-alt-maleic anhydride) chain. The availability of several anchoring groups in the same ligand greatly enhances the ligand affinity to the nanoparticle surfaces, via multiplecoordination, while the hydrophilic and reactive groups promote colloidal stability in buffer media and allow subsequent conjugation to target biomolecules. The hydrophilic nanoparticles capped with these polymers maintain compact size and exhibit great long term colloidal stability.

Single nanoparticle imaging is a powerful method to characterize nanoobjects and gain better understanding of their structural and optical properties. In our research we focus on plasmonic nanoparticles and particularly on anisotropic gold nanorods, which present interesting, polarization-dependent optical properties strictly correlated with their surface plasmon resonances. Here we discuss our results on two-photon excited luminescence imaging of a single gold nanorod. We analyze the dependence of the two-photon luminescence of a nanorod on the excitation wavelength, incident laser power and polarization, and contrast them with the data available in the literature.

Colloidal fluorescent semiconductor nanocrystals, named “quantum dots”, possess unique features, such as a tunable peak wavelength (according to their composition and their size) or a large absorption cross-section, that make them very attractive for biomedical imaging. Nevertheless, typical syntheses provide nanoparticles capped with hydrophobic ligands. To be used in long-term bioexperiments, they have thus to be modified to exhibit essentially a high colloidal stability in aqueous conditions, but also a low non-specific adsorption, a small size and functionalization moities. As all of these properties are controlled by the layer of coating ligands, we designed a bidentate monozwitterionic ligand, to first address the need of small-sized and antibiofouling hydrophilic probes. But the corresponding quantum dots revealed to be unstable in highly diluted conditions and difficult to functionalize. To further increase the affinity between the nanoparticles and their surrounding ligands, we synthesized a multidentate polyzwitterionic ligand, issued from the copolymerization of a bidentate monomer and a monozwitterionic one. The nanocrystals passivated by this polymeric ligand showed an exceptional colloidal stability, regardless of the medium conditions (pH, salinity, dilution, and biological environment), and we demonstrated the affinity of the polymer exceeded by three orders of magnitude that of the bidentate ligand. The synthesis of the multidentate polyzwitterionic ligand proved also to be easily tunable and allowed the facile introduction of reacting moieties. Further functionalization of the corresponding quantum dots with biomolecules led to successful specific targeting, which could be confirmed, as an example, through FRET experiments.

The field of nanotechnology is currently undergoing explosive development on many fronts. The technology is expected to generate innovations and play a critical role in cancer therapeutics. Among other nanoparticle (NP) systems, there has been tremendous progress made in the use of spherical gold NPs (GNPs) in cancer therapeutics. In treating cancer, radiation therapy and chemotherapy remain the most widely used treatment options. These nanostructures further provide strategies for improving loading, targeting, and controlling the release of drugs to minimize the side effects of highly toxic anticancer drugs used in chemotherapy. Our recent results show enhancement of cell death during radiation therapy when GNPs are targeted to nucleus. In addition, we have seen enhanced therapeutic effects when GNPs are used as anticancer drug carriers. Hence, gold nanostructures provide a versatile platform to integrate many therapeutic options leading to effective combinational therapy in the fight against cancer. A multifunctional platform based on gold nanostructures with targeting ligands, therapeutic molecules, and imaging contrast agents will hold the possibility of promising directions in cancer research.

Pseudomonas aeruginosa bacterium is a deadly pathogen, leading to respiratory failure in cystic fibrosis and nosocomial pneumonia, and responsible for high mortality rates in these diseases. P. aeruginosa has inherent as well as acquired resistance to many drug classes. In this paper, we investigate the effectiveness of two classes; aminoglycoside (tobramycin) and fluoroquinolone (ciprofloxacin) administered alone, as well as conjugated to iron oxide (magnetite) nanoparticles. P. aeruginosa possesses the ability to quickly alter its genetics to impart resistance to the presence of new, unrecognized treatments. As a response to this impending public health threat, we have synthesized and characterized magnetite nanoparticles capped with biodegradable short-chain carboxylic acid derivatives conjugated to common antibiotic drugs. The functionalized nanoparticles may carry the drug past the mucus and biofilm layers to target the bacterial colonies via magnetic gradient-guided transport. Additionally, the magnetic ferrofluid may be used under application of an oscillating magnetic field to raise the local temperature, causing biofilm disruption, slowed growth, and mechanical disruption. These abilities of the ferrofluid would also treat multi-drug resistant strains, which appear to be increasing in many nosocomial as well as acquired opportunistic infections. In this in vitro model, we show that the iron oxide alone can also inhibit bacterial growth and biofilm formation.

We describe the design and synthesis of two metal-coordinating zwitterion ligands to promote the transfer of hydrophobic QDs to buffer media over broad range of conditions. The ligands are prepared by appending either one or two lipoic acid anchoring groups onto a zwitterion, LA-TEG200-ZW and bis(LA)- ZW. Combining these ligands with a photochemical reduction of the lipoic acid group in the presence of UV irradiation, provides an easy to implement method to transfer luminescent QDs to buffer media, while preserving their optical and spectroscopic properties intact. The resulting zwitterion-QDs have very thin capping shell, which allows their self-assembly with full size proteins via metal-to-histidine coordination. These conjugates have great potential for use in various bio-motivated applications.

In this paper we present our recent studies on understanding how gold nanoparticles with defined characteristics in terms of size, shape, charge and function a) influence the formation of tight junctions between MDCK-II cells and b) interact with the cellular barrier of MDCK-II cells. We focused our work to seven types of gold nanoparticles, which are promising for biological applications or often employed as reference particles in biological experiments.

Hybrid nanostructures consisting of silver nanowires and photosynthetic complexes were assembled and investigated by means of fluorescence microscopy and spectroscopy, both in continuous-wave and time-resolved modes. Coupling emitters with varied spectral characteristics to plasmonic excitations in silver nanowires resulted in strong increase of fluorescence intensity and shortening of the decay times. In most cases, the emission observed at the ends of the nanowires is higher than for emitters placed along them. Overall, the results of these experiments indicate that silver nanowires are quite unique metallic nanostructures that can be used for enhancing optical properties, guiding plasmons over relatively large distances, as well as affecting the energy transfer between organic molecules.

More than a decade into the development of gold nanoparticles for cancer therapies, with multiple clinical trials underway, ongoing pre-clinical research continues towards better understanding in vivo interactions with the goal of treatment optimization through improved best practices. In an effort to collect information for healthcare providers, enabling informed decisions in a relevant time frame, instrumentation for real-time plasma concentration (multi-wavelength pulse photometry) and protocols for rapid elemental analysis (energy dispersive X-Ray fluorescence) of biopsied tumor tissue have been developed in a murine model. An initial analysis, designed to demonstrate the robust nature and utility of the techniques, revealed that area under the bioavailability curve (AUC) alone does not currently inform tumor accumulation with a high degree of accuracy (R²=0.32), This finding suggests that the control of additional experimental and physiological variables may yield more predictable tumor accumulation. Subject core temperature are blood pressure were monitored, but did not demonstrate clear trends. An effort to modulate AUC has produced an adjuvant therapy which is employed to enhance circulation parameters, including the AUC, of nanorods and gold nanoshells. Preliminary studies demonstrated a greater than 300% increase in average AUC through the use of a reticuloendothelial blockade agent versus control groups. Given a better understanding of the relative importance of the physiological factors which impact rates of tumor accumulation, a proposed set of experimental best practices is presented.

Quantum dots (QDs) with the highest possible photoluminescence quantum yields are necessary for modern nanotechnology applications to biosensing and optoelectronics. To date, core-shell QDs are the best. We suggest and demonstrate a novel approach to enhancement of charge-carrier confinement in the core of CdSe QDs by creating a ZnS/CdS/ZnS shell with staggered potential barrier. The CdS interlayer breaks the ZnS-shell structure continuity, which allows combining the benefits of a single ZnS-monolayer inner shell, creating the highest possible confinement potential, with a sufficient overall shell thickness and suitability for common surface modification techniques. This approach allows the preparation of CdSe-ZnS/CdS/ZnS QDs with photoluminescence quantum yields approaching 100% and small photoluminescence peak width.

Gold plasmonic nanoparticles are receiving attention for a variety of types of NIR optical biomedical imaging including photoacoustic imaging. Herein we present a novel method to assemble equilibrium gold nanoclusters from 5 nm primary gold nanospheres, which exhibit high near-infrared (NIR) absorbance and subsequently fully dissociate back to primary particles, which has the potential to enable renal clearance. The nanoparticle assembly is manipulated via controlling colloidal interactions, specifically electrostatic repulsion and depletion attraction. The charge on the primary ~5 nm gold nanospheres is tailored via place exchange reactions with a variety of biocompatible ligands such as citrate, lysine and cysteine. The primary particles form clusters upon addition of a biodegradable polymer, PLA(1k)-b- PEG(10k)-b-PLA(1k), followed by controlled solvent evaporation. The cluster size may be tuned from 20-40 nm in diameter by manipulating the gold and polymer concentrations along with the solvent evaporation extent. Salt is also added to increase the NIR absorbance and reduce the nanocluster size by reducing polymer adsorption. The adsorption of the polymer onto the Au surfaces effectively quenches the nanoclusters. High NIR absorption facilitates photoacoustic imaging, even for the small cluster sizes. In response to acidic cellular pH environments, the polymer degrades and the clusters dissociate back to primary particle on the order of 5 nm, which are small enough for renal clearance.

Semiconductor quantum dots (QDs) continue to emerge as a highly advantageous platform for bioanalysis. Their unique physical and optical properties are especially well suited for Förster resonance energy transfer (FRET)-based bioprobes. Concentric FRET configurations are a recent development in this area of research and are best described as QD bioconjugates where multiple energy transfer pathways have been assembled around the central QD. Concentric FRET configurations permit multiplexed bioanalysis using one type of QD vector, but require more sophisticated analyses than conventional FRET pairs. In this paper, we describe the design and characterization of a new concentric FRET configuration that assembles both a fluorescent dye, Alexa Fluor 555 or Alexa Fluor 647, and a dark quencher, QSY9, at different ratios around a central CdSeS/ZnS QD. It was found that the magnitudes of the total photoluminescence (PL) intensity and either the A555/QD or A647/QD PL ratio can be related to the number of QSY9 and A555 or A647 per QD. The trends in these parameters with changes in the number of each dye molecule per QD have both similarities and differences between configurations with A555 and A647. In each case, a system of equations can be defined to permit calculation of the number of each dye molecule per QD from PL measurements. Both of these dark quencher-based concentric FRET configurations are therefore good candidates for quantitative, multiplexed bioanalysis.

Quantum dots (QDs) are of high interest in the biomedical field. The most widely used and commercially available CdSe/ZnS QDs have a highly toxic Cd component. High-efficiency luminescent Cd-free Mn-doped ZnSe/ZnS QDs are a reasonable alternative to CdSe/ZnS QDs; however the actual cytotoxicity of ZnSe:Mn/ZnS QDs is relatively unknown. In this study, we apply the ApoTox-Glo^TM Triplex assay to test for cell cytotoxicity, viability, and induced apoptosis, by treating macrophage cells with different concentrations of peptide-coated ZnSe:Mn/ZnS QDs at four different incubation times: 6, 12, 24, and 48 hours. At the concentrations used, which varied between 0.03 μM to 0.25 μM, the macrophage cells showed very little cytotoxic effect. However, cell viability began to decrease with increasing QD concentration beginning with the 12 hour incubation time, with fairly consistent results for 24 and 48 hour incubation times as well. Also, the macrophage cells expressed a measurable degree of induced apoptosis, which scaled with concentration. While cytotoxicity did not seem to be an issue with macrophage cells treated with the peptide-coated Mn-doped ZnSe/ZnS QDs, the drop in cell viability and the increase in induced apoptosis suggest an antiproliferation effect within the macrophage cell culture.

The need to detect cancer at its early stages, as well as, to deliver chemotherapy to targeted site motivates many researchers to build theranostic platforms which combine diagnostic and therapy. Among imaging modalities, ultrasonography and Magnetic Resonance Imaging (MRI) are widely available, non invasive and complement each other. Both techniques often require the use of contrast agents. We have developed nanocapsules of perfluorooctyl bromide as dual contrast agent for both imaging modalities. The soft, amorphous polymer shell provides echogenicity, while the high-density perfluorinated liquid core allows detection by ¹⁹F MRI. We have used a shell of poly(lactide-co-glycolide) (PLGA) since this polymer is biodegradable, biocompatible and can be loaded with drugs. These capsules were shown to be efficient in vitro as contrast agents for both ¹⁹F MRI and ultrasonography. In addition, for in vivo applications a poly(ethyleneglycol) (PEG) coating promotes stability and prolonged circulation. Being stealth, nanocapsule can accumulate passively into implanted tumors by the EPR effect. We will present nanocapsule formulation and characterization, and will show promising in vivo results obtained for both ultrasonography and ¹⁹F MRI.

Recently, we have demonstrated the magnetic field-enriched surface-enhanced resonance Raman spectroscopy (SERRS) of β-hematin by using nanoparticles with iron oxide core and silver shell (Fe₃O₄@Ag) for the potential application in the early malaria diagnosis. In this study, we investigate the dependence of the magnetic field-enriched SERRS performance of β-hematin on the different core and shell sizes of the Fe₃O₄@Ag nanoparticles. We note that the core and shell parameters are critical in the realization of the optimal magnetic field-enrich SERRS β-hematin signal. These results are consistent with our simulations that will guide the optimization of the magnetic SERRS performance for the potential early diagnosis in the malaria disease.

Research on magnetic nanocrystals attracts wide-spread interest because of their challenging fundamental properties, but it is also driven by problems of practical importance to the society, ranging from electronics (e.g. magnetic recording) to biomedicine. In that respect, iron oxides are model functional materials as they adopt a variety of oxidation states and coordinations that facilitate their use. We show that a promising way to engineer further their technological potential in diagnosis and therapy is the assembly of primary nanocrystals into larger colloidal entities, possibly with increased structural complexity. In this context, elevated-temperature nanochemistry (c.f. based on a polyol approach) permitted us to develop size-tunable, low-cytotoxicity iron-oxide nanoclusters, entailing iso-oriented nanocrystals, with enhanced magnetization. Experimental (magnetometry, electron microscopy, Mössbauer and NMR spectroscopies) results supported by Monte Carlo simulations are reviewed to show that such assemblies of surface-functionalized iron oxide nanocrystals have a strong potential for innovation. The clusters’ optimized magnetic anisotropy (including microscopic surface spin disorder) and weak ferrimagnetism at room temperature, while they do not undermine colloidal stability, endow them a profound advantage as efficient MRI contrast agents and hyperthermic mediators with important biomedical potential.

Gold nanorods (GNRs) are optimal contrast agents for near-infrared (NIR) laser-induced photothermal ablation of cancer. Selective targeting of cancer cells can be pursued by attaching specific molecules on the particles surface or by the use of cellular vectors loaded with GNRs. We performed and tested various targeting approaches by means of GNRs functionalization with (i) antibodies against Cancer-Antigen-125 (CA-125), (ii) inhibitors of the carbonic anhydrase 9 (CA9) and (iii) by the use of macrophages as cellular vectors. GNRs with a NIR absorption band at 810 nm were synthesized and PEGylated. For GNRs functionalization the targets of choice were CA-125, the most widely used biomarker for ovarian cancer, and CA9, overexpressed by hypoxic cells which are often located within the tumor mass. In the case of cellular vectors, to be used as Trojan horses naturally able to reach tumor areas, the surface of PEG-GNRs was modified to achieve unspecific interactions with macrophage membranes. In all cases the cellular uptake was evaluated by silver staining and cell viability was assessed by MTT test. Then tests of laser-induced GNRs-mediated hyperthermia were performed in various cell cultures illuminating with an 810 nm diode laser (CW, 0,5-4 W/cm² power density, 1-10 min exposure time) and cell death was evaluated. Each targeting strategy we tested may be used alone or in combination, to maximize the tumor loading and therefore the efficiency of the laser treatment. Moreover, a multiple approach could help when the tumor variability interferes with the targeting directed to a single marker.

Traditional in vitro diagnostics requires specialized laboratories and costly instrumentation, both for the amplification of nucleic acid targets (usually achieved by PCR) and for the assay readout, often based on fluorescence. We are developing hybrid nanomaterials-based sensors for the rapid and low-cost diagnosis of various disease biomarkers, for applications in portable platforms for diagnostics at the point-of-care. To this aim, we exploited the size and distancedependent optical properties of gold nanoparticles (AuNPs) to achieve colorimetric detection. Moreover, in order to avoid the complexity of thermal cycles associated to traditional PCR, the design of our systems includes signal amplification schemes, achieved by the use of enzymes (nucleases, helicase) or DNAzymes. Focused on instrument-free and sensitive detection, we carefully combined the intrinsic sensitivity by multivalency of functionalized AuNPs with isothermal and non-stringent enzyme-aided reaction conditions, controlled AuNPs aggregates, universal reporters and magnetic microparticles, the latter used both as a substrate and as a means for the colorimetric detection. We obtained simple and robust assays for the sensitive (pM range or better) naked-eye detection of cancer or infectious diseases (HPV, HCV) biomarkers, requiring no instrumentation except for a simple heating plate. Finally, we are also developing non-medical applications of these bio-nanosensors, such as in the development of on-field rapid tests for the detection of pollutants and other food and water contaminants.

The combination of laser light and composite nanovesicles enables unique opportunities for precise delivery to, and ondemand release of molecular compounds within, single cells at high spatiotemporal resolution. Here, we demonstrate precise delivery and intracellular release of molecules from gold-coated liposomes via near infrared (NIR) light. The plasmon resonant gold shell provides a light-sensitive trigger for on-demand content release from thermosensitive liposomes. Two demonstrations of intracellular delivery and release from gold-coated liposomes are presented here. The first example uses microinjection to preload gold-coated liposomes into a single cell, followed by exposure to onresonant NIR laser light to trigger release of a fluorescent nuclear dye intracellularly. In the second delivery and release demonstration, gold-coated liposomes encapsulating inositol trisphosphate (IP3), a ubiquitous secondary messenger in cell signaling cascades, passively accumulate within cells via endocytosis. Exposure to on-resonant NIR laser wavelength of light induces rapid release of IP3 from the intracellular liposomes and subsequent activation of Ca²⁺ signaling at a single cell, monitored by changes in fluorescence intensity of a Ca ²⁺-sensitive dye.

Quantum dots allow the generation of charge carriers upon illumination. When these particles are attached to an electrode a photocurrent can be generated. This allows their use as a light-switchable layer on the surface. The QDs can not only exchange electronics with the electrode, but can also interact with donor or acceptor compounds in solution providing access to the construction of signal chains starting from an analytic molecule. The magnitude and the direction of the photocurrent depend on several factors such as electrode polarization, solution pH and composition. These defined dependencies have been evaluated with respect to the combination of QD-electrodes with enzyme reactions for sensorial purpose. CdSe/ZnS-QD-modified electrodes can be used to follow enzymatic reactions in solution based on the oxygen sensitivity. In order to develop a photoelectrochemical biosensor, e.g. glucose oxidase is immobilized on the CdSe/ZnS-electrode. One immobilization strategy applies the layer-by-layer-technique of GOD and a polyelectrolyte. Photocurrent measurements of such a sensor show a clear concentration dependent behavior. The principle of combing QD oxidase. The sensitivity of quantum dot electrodes can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be demonstrated that direct electron transfer from excited quantum dots can be achieved with the redox protein cytochrome c. This allows the detection of the protein, but also interaction partners such as a enzymes or superoxide.

The main goal of this study was to investigate the sensitivity of microorganisms to combined action of blue light and iron oxide nanoparticles. Two strains of Staphylococcus aureus – methicillin-sensitive and meticillin-resistant were used. As a blue light source LED with spectral maximum at 405 nm was taken. The light exposure was ranged from 5 to 30 min. The Fe₂O₃ (diameter ∼27 nm), Fe3O4 nanoparticles (diameter ∼19 nm), and composite Fe₂O₃/TiO₂ nanoparticles (diameter ∼100 nm) were synthesized. It was shown that irradiation by blue light caused from 20% to 88% decrease in the number of microorganisms treated with nanoparticles. Morphological changes in bacterial cells after phototreatment were analyzed using scanning electron microscope.

Photoirradiation effect of gold nanospheres in conjucation with green light and rods in conjugation with red light corresponds to their absorption wavelength range found to be appreciable. In this present work concentration of nanomaterial and light dose were optimized. Gold nanospheres were synthesized by reduction technique using Sodium Borohydrate as reducing agent and Trisodium Citrate as capping agent. Au nanorods having 680-900nm absorption were synthesized using reduction techniques with CTAB and BDAC polymers. From UV-Vis absorption and Transmission Electron Microscopy the size of nanoparticles were confirmed. 30nm Gold nanospheres and green light source of 530nm wavelength with power 30mW were applied to Vero and Hela cell lines shows higher toxicity for Hela cells. Nanorods were applied and irradiated with 680nm wavelength light source with light intensity 45mW. Post irradiation effect for 24hrs, 48hrs confirms cell proliferation in normal rate in viable cells. The morphological changes in irradiated spot leads to apoptotoic cell death was confirmed with microscopic imaging. The LD50 value was also calculated.

Templating semiconductor nanoparticles’ growth on the surface of biological self-assembled molecules is a promising avenue over the limitations that top-down techniques may impose on device fabrication. We report on two-dimensional ordered structures of preformed TOPO (trioctylphosphine oxide) capped CdSe@ZnS core-shell quantum dots (Qdots) on self-assembled peptide fibrils. An amphiphilic peptide was employed both as ligand-exchange element (via its cysteine residues) and as a structural scaffold for the ordering of Qdots at the water-chloroform interface. We discuss the topological arrangement of the Qdots as imposed by the peptide fibril film and the impact of the assembly on the materials’ photoluminescent properties, which display signatures of long-range electronic energy transfer.

We describe the design and optimization of an amphiphilic diblock copolymer and its use to provide surface functionalization of colloidal semiconductor nanoparticles (quantum dots, QDs). This polymer coating promotes hydrophilicity of the nanocrystals while providing numerous functional groups ideally suited for biofunctionalization of the QDs using copper-catalyzed azide alkyne Husigen 1,3-cyloaddition (i.e., cupper catalyzed “click” reaction). Copper ions are known to quench the fluorescence of QDs in solution. Thus effective shielding of the nanocrystal surface is essential to apply copper-catalyzed reactions to luminescent QDs without drastically quenching their emission. We have applied a strategy based on micellar encapsulation within poly(isoprene-block- ethylene oxide) diblock-copolymers (PI-b-PEO), where three critical factors promote and control the effectiveness of the shielding of copper ion penetration: 1) The excess of PI-b-PEO, 2) the size of PI-b-PEO and 3) insertion of an additional PS-shell grown via seeded emulsion polymerization (EP) reaction. Due to the amphiphilic character of the block-copolymer, this approach provides a shielding layer surrounding the particles, preventing metal ions from reaching the QD surfaces and maintaining high photoluminescence. The effective shielding allowed the use of copper-catalyzed azide-alkyne 1,3-cycloaddition (CuAAC) to hydrophilic and highly fluorescent QDs, opening up great possibilities for the bio functionalization of QDs.