• Physique/Physique/Biophysique
  
• Sciences du Vivant/Ingénierie biomédicale/Biomatériaux
  
• Physique/Matière Condensée/Science des matériaux
  
• Sciences de l'ingénieur/Microélectronique
  
• Sciences du Vivant/Biochimie, Biologie Moléculaire/Biologie moléculaire
  
• Sciences du Vivant/Médecine humaine et pathologie/Rhumatologie et système ostéo-articulaire
  
• Physique/Matière Condensée/Autre
  

Cost-effective health care technologies for detection of disease biomarkers at ultralow concentrations can significantly improve the quality of life in resource-constrained countries. However, current techniques require expensive instruments, complex conjugation protocols and tedious laboratory procedures that may not be affordable for the major part of the world population. Here, we propose to sidestep the problem by establishing a simple, relatively inexpensive sensing method employing a photonic substrate, a material affinity peptide, and a smart phone CCD detector to achieve detection of clinically relevant proteins in serum at concentrations much lower than standard enzyme-linked immunosorbent assay (ELISA). Easy to process porous silicon (PSi) micro-cavities were employed as substrates that provide a three-dimensionality, large surface area, and convenient light enhancement properties for molecular detection. Anti-histone H2B antibodies and biomarkers of severe illnesses are detected in whole serum at concentrations as low as 10 fg mL−1 by using the proposed PSi-ELISA protocol. Due to its easy use, cost effectiveness and high sensitivity, the proposed method has potential large- scale applications in ultrasensitive sensing of different other clinically relevant molecules for early stage diagnostics.

Casein micelle (CM), porous colloidal phosphoprotein-mineral complex, naturally present in milk to deliver minerals, also has several features, which could ensure its use as nanocarrier for bioactives. CM structure being not steady according to the physico-chemical conditions, its stability can be improved by intra-micellar cross-linking using transglutaminase (TGase) inducing a strengthened structure called casein nanogel. The aim of this research was to investigate the morphology and nanomechanics of casein nanogel particles cross-linked by TGase (TG-CM) using atomic force microscopy (AFM) in native-like liquid environment (lactose-free simulated milk ultrafiltrate, SMUF). Prior to AFM, TG-CM were captured by anti-phospho-Ser/Thr/Tyr monoclonal antibodies covalently bound to a gold-coated slide via carbodiimide chemistry. Surface topography and size properties evaluation revealed an increase in size of TG-CM compared to native CM, TG-CM being characterized by a mean width of 264 ± 7 nm and a mean height of 111 ± 5 nm. TG-CM displayed a relatively high contact angle (62°) indicating a limited flattening of these particles after adsorption on the substrate. The TG-CM elasticity was then evaluated applying low indentation forces on single TG-CM. The TGase treatment led to a significant modification of CM nanomechanics attributed to intramolecular rearrangements within the micellar structure. The elasticity distribution of TG-CM revealed three elasticity peaks centered at 219±14kPa, 536±14kPa and 711 ± 11 kPa. The lower elasticity peak is related to the native CM nanomechanical signature and the two stiffer peaks were attributed to the substantial changes in the TG-CM structure.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that a ects the motorsystem leading to generalized paralysis and death of patients. The understanding of early pathogenic mechanisms will help to de ne early diagnostics criteria that will eventually provide basis for e cient therapeutics. Early symptoms of ALS usually include muscle weakness or sti ness. Therefore, mechanical response of di erentiated myotubes from primary cultures of mice, expressing the ALS- causing SOD1G93A mutation, was examined by atomic force microscopy. Simultaneous acquisition of topography and cell elasticity of ALS myotubes was performed by force mapping method, compared with healthy myotubes and supplemented with immuno uorescence and qRT-PCR studies. Wildtype myotubes reveal a signi cant di erence in elasticity between a narrow and a wide population, consistent with maturation occurring with higher actin expression relative to myosin together with larger myotube width. However, this is not true for SOD1G93A expressing myotubes, where a signi cant shift of thin population towards higher elastic modulus values was observed. We provide evidence that SOD1 mutant induces structural changes that occurs very early in muscle development and well before symptomatic stage of the disease. These ndings could signi cantly contribute to the understanding of the role of skeletal muscle in ALS pathogenesis.

Luminescent nanodiamonds (ND) are attractive tools for nanoscale biologic cellular imaging allowing both photoluminescence (PL) and magnetic resonance imaging [1]. Recent technological developments enable to fabricate bright NDs with high content of nitrogen-vacancy centres [2] that are anticipated to serve as a cell probes. In this work we present novel method of NDs detection in cellular environment. We demonstrate simultaneous visualization of NDs and of the non- labeled nucleus of living cells based on Raman and PL detection as a new tool for the localization of internalized nanoparticles.To this end, NDs of size ranging from ultra-small particles ~ 5 nm to 60 nm were used, prepared from Ib synthetic diamond. Cells used for this experiment were from mammalian breast cancer (MCF7). We report on accomplishing to successfully internalize ND particles in MCF7 cells. We show that ND internalization can be monitored by Raman imaging method using K-mean cluster analysis. Whilst standard Raman imaging methods of NDs make use of the sp3 diamond Raman signal, which limits their use to 100 nm size particles or bigger [3], here we employ Raman imaging in a novel way to detect small near-IR cellular probe. Changes of cells stiffness were detected by force measurement in atomic force microscopy after incubating cells with NDs, suggesting cell membrane hardening upon ND uptake.[1] L. Moore, M. Nesladek et al., Nanoscale (2014)[2] J. Havlik, M. Gulka, M. Nesladek et al., Nanoscale (2013) [3] C.-Y. Cheng et al., Applied Physics Letter (2007)

We are interested in the early stage diagnosis of H2B, a clinically important autoantigen in various severe illnesses (can-cers, systemic lupus, rheumatoid arthritis). Accordingly, we have developed a porous-silicon (PSi) based enzyme-linked immunosorbent assay (ELISA) for sensitive detection of H2B antibodies, where H2B antigen were bound to a Si binding 12mer peptide [1] that act as an efficient linker to the surface. The proposed method is a simple, inexpensive sensing meth-od employing a PSi photonic substrate, a material affinity peptide, and a smart phone CCD detector to achieve a 100-fold (~ 10 fg/ml) increase in sensitivity compared to the standard ELISA (0.01 -0.1 ng/ml).