Controlling the Luminescence of Carboxyl-Functionalized CdSe/ZnS Core–Shell Quantum Dots in Solution by Binding with Gold Nanorods

Plasmonic nanostructures offer promising routes toward artificial control of the photoluminescence properties of various emitters. Here, we investigated the photoluminescence of carboxyl-functionalized CdSe/ZnS core–shell quantum dots (c-QDs) localized near gold nanorods (AuNRs) as a function of c-QDs–AuNRs distance using the cetyltrimethylammonium bromide (CTAB) surfactant and Bovine Serum Albumin (BSA) protein layers over coating metal surface as spacer. The direct binding of negatively charged c-QDs to positively charged CTAB (3–4 nm thickness) caused close contact with the metal, resulting in an efficient metal-induced energy transfer (quenching). We found that quenching is modulated by the degree of spectral overlap between the photoluminescence band of c-QDs (620 nm) and longitudinal localized surface plasmon resonance (LSPR) of AuNRs (637 and 733 nm). Deposition of BSA layer over CTAB coated-AuNRs and subsequent decoration with c-QDs yielded an increase in photoluminescence signal when exciting in resonance with the transverse LSPR of AuNRs. On the basis of experimental studies using steady-state and time-resolved fluorescence measurements as well as finite-difference time-domain calculations, we report over 70% quenching efficiency for all investigated AuNRs along with a 4.6-fold in photoluminescence enhancement relative to free c-QDs (39-fold enhancement relative to c-QDs loaded AuNRs) after BSA deposition

Copolymerization of recombinant <i>Phascolopsis</i> <i>gouldii</i> hemerythrin with human serum albumin for use in blood substitutes

<p>Hemerythrin is an oxygen-carrying protein found in marine invertebrates and may be a promising alternative to hemoglobin for use in blood substitutes, primarily due to its negligible peroxidative toxicity. Previous studies have shown that glutaraldehyde-induced copolymerization of hemoglobin with bovine serum albumin increases the half-life of the active <i>oxy</i> form of hemoglobin (i.e. decreases the auto-oxidation rate). Here, we describe a protocol for glutaraldehyde copolymerization of Hr with human serum albumin and the dioxygen-binding properties of the co-polymerized products. The copolymerization with HSA results in alteration of hemerythrin’s dioxygen-binding properties in directions that may be favorable for use in blood substitutes.</p

Antibody Conjugated, Raman Tagged Hollow Gold–Silver Nanospheres for Specific Targeting and Multimodal Dark-Field/SERS/Two Photon-FLIM Imaging of CD19(+) B Lymphoblasts

In this Research Article, we propose a new class of contrast agents for the detection and multimodal imaging of CD19­(+) cancer lymphoblasts. The agents are based on NIR responsive hollow gold–silver nanospheres conjugated with antiCD19 monoclonal antibodies and marked with Nile Blue (NB) SERS active molecules (HNS-NB-PEG-antiCD19). Proof of concept experiments on specificity of the complex for the investigated cells was achieved by transmission electron microscopy (TEM). The microspectroscopic investigations via dark field (DF), surface-enhanced Raman spectroscopy (SERS), and two-photon excited fluorescence lifetime imaging microscopy (TPE-FLIM) corroborate with TEM and demonstrate successful and preferential internalization of the antibody-nanocomplex. The combination of the microspectroscopic techniques enables contrast and sensitivity that competes with more invasive and time demanding cell imaging modalities, while depth sectioning images provide real time localization of the nanoparticles in the whole cytoplasm at the entire depth of the cells. Our findings prove that HNS-NB-PEG-antiCD19 represent a promising type of new contrast agents with great possibility of being detected by multiple, non invasive, rapid and accessible microspectroscopic techniques and real applicability for specific targeting of CD19­(+) cancer cells. Such versatile nanocomplexes combine in one single platform the detection and imaging of cancer lymphoblasts by DF, SERS, and TPE-FLIM microspectroscopy

Additional file 5: Figure S1. of Dental follicle stem cells in bone regeneration on titanium implants

Neuronal differentiation of Df stem cells. Protocol of neuronal differentiation. DF stem cells were seeded in 6 well plates at cell density of 20 × 105 cells/well. When cells reached confluence a two steps protocol was applied: cells were cultivated for 48 h in presence of neuronal differentiation medium 1 consisting of DMEM high glucose/F12-HAM (1:1 ratio), 10 % fetal bovine serum (FBS), 1 % antibiotics,2 mM glutamine, 1 % non-essential aminoacids (NEA), supplemented with 10 ng/ml Epidermal Growth Factor (EGF), 10 ng/ml basic Fibroblast Growth Factor (bFGF), 2 % B27 and 1 % N2 Supplement. Afterwards cells were exposed to the differentiation medium 2 for 3 weeks: DMEM high glucose/F12-HAM, 10 % FBS, 1 % antibiotics, 2 mM glutamine, 1 % NEA, 1 % N2 Supplement, 2 % B27 Supplement, 3 μM all-trans retinoic acid, 0.5 mM 3-isobutyl-1-methyl-xanthine (IBMX) (all reagents were purchased from Sigma Aldrich). At the end of 3 weeks of DF stem cultivation with neuronal differentiation medium, cells were fixed and immunocytochemical stained for neurofilaments and CD 133 expression. As shown in Figure S1, the stained cells expressed positivity only for neurofilaments. Figure S1: Fluorescence image of DF stem cells induced to differentiate into neuronal cells. Cells were stained with anti neurofilaments antibody conjugated with FITC green), anti CD 133 conjugated with Texas red (red) and nuclei were counterstained with DAPI (magnification ×100). (PNG 451 kb

Additional file 2: Figure S2. of Dental follicle stem cells in bone regeneration on titanium implants

FDA (fluorescein diacetate) viability test. DF stem cell adhesion after 1 h as well the proliferation rate during 48 h and 7 days of cultivation on titanium implants surfaces were investigated using FDA assay. Images were captured in fluorescence microscopy at 488 nm with a Zeiss Axiovert microscope. Image acquisition was performed with an AxioCam MRC camera. Figure S2: Fluorescence images captured after FDA staining of DF stemm cells after 1, 48 h and 7 days of cultivation in standard stem cell medium. (Legend: TiCtrl- Ti6Al7Nb alloy porous titanium, TiHA-titanium infiltrated with hydroxyapatite, TiSiO2-titanium infiltrated with silicatitanate) (magnification ×100). (PNG 940 kb

Additional file 6: Figure S6. of Dental follicle stem cells in bone regeneration on titanium implants

The physical chemical characterization of titanium coatings. For proving that by used sol–gel method we obtain these nanocrystalline forms of HA and anatase, after heat treatments at quite low temperatures. Figure S6: XRD pattern of hydroxyapatite sample after 600 oC heat treatment. (PNG 7 kb

Additional file 3: Figure S3. of Dental follicle stem cells in bone regeneration on titanium implants

Alamar Blue viability assay. For testing the viability and proliferation rate of DF stem cells cultivated on titanium implants, cells seeded at a cell density of 1.2 × 105 cells/well in 12-wells plates were stained with Alamar blue solution at different periods of time (24 h, 4 and 12 days). Briefly, 100 μl of Alamar blue solution (Invitrogen) was added in each well containing 900 μl stem cell medium or differentiation medium (OS and OC). Each sample was evaluated in triplicate. After 1 h of incubation in dark at 37 °C, the medium was transferred to another 12-well plates and the absorbance was read using a BioTek Synergy 2 plate reader at 570 nm (Winooski, VT, USA). Statistical analysis was performed using t test and two-way ANOVA, Bonferroni posttest. Results: No important differences were observed between titanium implants in terms of cell viability. Statistical differences were noticed only for the 24 h culture between cell cultured on control titanium implants (Ti ctrl) and implants infiltrated with HA (Ti HA) (Figure S3). Two-way ANOVA statistical analysis revealed differences regarding the time factor (24 h vs. 12 days and 4 vs. 12 days) Figure S3: Graphical aspect of optical density values (absorbance at 570 nm) of Alamar blue staining of DF stem cells cultivated with standard stem cell medium evaluated after 24 h, 4 and 12 days (Legend: TiCtrl- Ti6Al7Nb alloy porous titanium, TiHA-titanium infiltrated with hydroxyapatite, TiSiO2-titanium infiltrated with silicatitanate). (PNG 1002 kb