Anti-CD19 Gold Nanostars as New Therapeutic Vectors for the Treatment of Acute Lymphoblastic Leukemia

Extended Abstract Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in children, and the second most common in adolescents. This disease is characterised by a wide palette of genetic causes, which create many possible protein expression profiles, allowing for a targeted treatment for each patient The objective of our work is to specifically target ALL cells using antibody-tagged nanoparticles and to demonstrate improved cell uptake, feature that will be later harnessed for further treatment options. Our scope is to perform a series of cellular tests, where cells are incubated with targeted and non-targeted nanoparticles, and to monitor the outcome of the experiment. Targeted nanoparticles are more likely to get in direct contact to the cell surface by specific antibody-antigen interactions, thus increasing the internalisation probability. Using methods such as dark-field microscopy imaging, confocal Raman imaging, and transmission electron microscopy, we monitor the presence and localisation of our nanoparticle complexes at the cellular level. Also, by employing cell toxicity, viability and proliferation assays we assess the therapeutic effect of the conjugated particles onto ALL cells. In this study, we prepared star-shaped gold nanoparticles by a seed-mediated chemical synthesis, we biocompatilised the particles with PEG polymer and conjugated the particles with anti-CD19 antibody specifically selected for ALL cell targetin

New insight into the aptamer conformation and aptamer/protein interaction by surface-enhanced Raman scattering and multivariate statistical analysis

International audienceWe study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced. We demonstrate that the aptamer orientation and thus its flexibility rely strongly on the presence of a spacer of 15 thymines and on the experimental conditions with the aptamer lying on the surface in air and standing in the buffer. We reveal for the first time that the interaction with MnSOD induces a large loss of flexibility and freezes the aptamer structure in a single conformation

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