Publications de Ahmet Bekdemir

Calcium-triggered fusion of lipid membranes is enabled by amphiphilic nanoparticles

Francesco Stellacci, Zekiye Pelin Güven, Ye Yang, Ahmet Bekdemir

Lipid membrane fusion is an essential process for a number of critical biological functions. The overall process is thermodynamically favorable but faces multiple kinetic barriers along the way. Inspired by nature's engineered proteins such as SNAP recepto ...

National Academy of Sciences2020

Reproducibility warning: The curious case of polyethylene glycol 6000 and spheroid cell culture

Francesco Stellacci, Quy Ong Khac, Zhi Luo, Ahmet Bekdemir

Reproducibility of results is essential for a well-designed and conducted experiment. Several reasons may originate failure in reproducing data, such as selective reporting, low statistical power, or poor analysis. In this study, we used PEG6000 samples fr ...

2020

On the effect of ligand shell heterogeneity on nanoparticle/protein binding thermodynamics

Francesco Stellacci, Ahmet Bekdemir, Suiyang Liao

Nonspecific protein adhesion to nanoparticle (NP) has been proven to have important implications in nanomedicine. However, there are only a few examples of careful studies relating protein binding thermodynamics to NP physicochemical features. In particula ...

2019

Amphiphilic nanoparticle delivery enhances the anticancer efficacy of a TLR7 ligand via local immune activation

Francesco Stellacci, Marie Mueller, Ye Yang, Ahmet Bekdemir

Although immunotherapy shows great promise for the long-term control of cancer, many tumors still fail to respond to treatment. To improve the outcome, the delivery of immunostimulants to the lymph nodes draining the tumor, where the antitumor immune respo ...

ELSEVIER SCI LTD2019

Targeting small molecule drugs to T cells with antibody-directed cell-penetrating gold nanoparticles

Francesco Stellacci, Ye Yang, Ahmet Bekdemir

We sought to develop a nanoparticle vehicle that could efficiently deliver small molecule drugs to target lymphocyte populations. The synthesized amphiphilic organic ligand-protected gold nanoparticles (amph-NPs) were capable of sequestering large payloads ...

2019

Modular soft robotic microdevices for dexterous biomanipulation

Lucio Feo Pancaldi-Giubbini, Francesco Stellacci, Ahmet Bekdemir, Mahmut Selman Sakar, Raquel Filipa Penacho Parreira, Ece Özelçi, Berna Ayse Özkale Edelmann, Murat Kaynak

We present a methodology for building biologically inspired, soft microelectromechanical systems (MEMS) devices. Our strategy combines several advanced techniques including programmable colloidal self-assembly, light-harvesting with plasmonic nanotransduce ...

2019

Broad-spectrum non-toxic antiviral nanoparticles with a virucidal inhibition mechanism

Francesco Stellacci, Paulo Henrique Jacob Silva, Marie Mueller, Ahmet Bekdemir, Samuel Thomas Jones, Emma-Rose Janecek, Valeria Cagno

Viral infections kill millions yearly. Available antiviral drugs are virus-specific and active against a limited panel of human pathogens. There are broad-spectrum substances that prevent the first step of virus–cell interaction by mimicking heparan sulfat ...

2018

Investigation of nanoparticle-protein interactions with novel methods

Ahmet Bekdemir

Advancements in novel nanomaterials present promising avenue for therapeutics and diagnosis in nanomedicine. Importantly, in these applications, nanoparticles (NPs) are almost instantly coated with a complex layer of proteins in biological environment, ter ...

EPFL2018

Structure-Property Relationships of Amphiphilic Nanoparticles That Penetrate or Fuse Lipid Membranes

Davide Demurtas, Francesco Stellacci, Randy Patrick Carney, Paulo Henrique Jacob Silva, Zekiye Pelin Güven, Ye Yang, Ahmet Bekdemir

2018

High-throughput quantitation of inorganic nanoparticle biodistribution at the single-cell level using mass cytometry

Francesco Stellacci, Ye Yang, Ahmet Bekdemir, Li Tang

Inorganic nanoparticles (NPs) are studied as drug carriers, radiosensitizers and imaging agents, and characterizing nanoparticle biodistribution is essential for evaluating their efficacy and safety. Tracking NPs at the single-cell level with current techn ...

Nature Publishing Group2017

Nanoparticles comprising a metal core surrounded by a monolayer for lymph node targeting

Francesco Stellacci, Ye Yang, Ahmet Bekdemir

Amphiphilic gold nanoparticles (amph-NPs), composed of gold cores surrounded by an amphiphilic mixed organic ligand shell, are capable of embedding within and traversing lipid membranes. Active agent is bound thereto for use in vaccine and other adjuvant t ...

2017

Gold Nanostar-Coated Polystyrene Beads as Multifunctional Nanoprobes for SERS Bioimaging

Francesco Stellacci, Ahmet Bekdemir

Hybrid colloidal nanocomposites comprising polystyrene beads and plasmonic gold nanostars are reported as multifunctional optical nanoprobes. Such self-assembled structures are excellent Raman enhancers for bioapplications as they feature plasmon modes in ...

American Chemical Society2016

A centrifugation-based physicochemical characterization method for the interaction between proteins and nanoparticles

Francesco Stellacci, Ahmet Bekdemir

Nanomedicine requires in-depth knowledge of nanoparticle-protein interactions. These interactions are studied with methods limited to large or fluorescently labelled nanoparticles as they rely on scattering or fluorescence-correlation signals. Here, we hav ...

Nature Publishing Group2016

A Multilaboratory Comparison of Calibration Accuracy and the Performance of External References in Analytical Ultracentrifugation

Jutta Christine Wandrey, Helmut Coelfen, Ahmet Bekdemir

Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this ...

Public Library of Science2015

Influence of the glycocalyx and plasma membrane composition on amphiphilic gold nanoparticle association with erythrocytes

Francesco Stellacci, Randy Patrick Carney, Paulo Henrique Jacob Silva, Ye Yang, Ahmet Bekdemir

Erythrocytes are attractive as potential cell-based drug carriers because of their abundance and long life-span in vivo. Existing methods for loading drug cargos into erythrocytes include hypotonic treatments, electroporation, and covalent attachment onto ...

Royal Society of Chemistry2015