Nanotechnology approaches to self-organized bio-molecular devices

Abstract In this paper we briefly describe new strategies to exploit self-assembled solid-state biomolecular materials as active elements of electronic devices. Two basically different approaches are proposed: a top-down approach, where biomolecular semiconductors consisting of DNA basis are self-organized and interconnected by planar metallic nanopatterns, and a bottom-up approach, where single or ordered matalloproteins are immobilized in a nanocircuit realizing a hybrid covalently bound biologic–inorganic system. The transport characteristics of different devices such as diodes, photodetectors and metal–semiconductor–metal structures will be described

Liquid biopsy in gastrointestinal stromal tumors: a novel approach

The role of molecular analysis in the management of gastrointestinal stromal tumors (GIST) remains indisputable. To date, tumor tissue extracted from specimens obtained by surgical or biopsy procedures has been the only source of the tumor DNA required for the molecular and genomic assessment of cancer. However, tumor tissue sampling has several clinical limitations: for example, the invasiveness of these procedures precludes repeated sampling. Thus, it is possible to obtain only a static molecular picture of the disease, a picture that lacks the inter- and intra-metastatic molecular heterogeneity that characterizes most GIST. In contrast, circulating tumor DNA obtained from a patient's bloodstream, known as liquid biopsy, can theoretically overcome the limitations of tissue biopsies and provide the same molecular and genomic information. GIST are recognized as a paradigm of molecular biology among solid tumors. Although few but promising data on liquid biopsy in GIST have been accumulated to date, these tumors may provide the optimal field for application of this challenging approac

Molecular determination of epidermal growth factor receptor in normal and neoplastic colorectal mucosa

The epidermal growth factor receptor (EGFr) is considered a major target for treatment of colorectal cancer (CRC). We found a mean EGFr content significantly lower but more activated in colonic neoplastic tissue than in paired normal mucosa. Phosphorylated (pY1068) EGFr detection in CRC may be a better tool than EGFr detection to select patients for targeted therapies

A protein-based three terminal electronic device.

: Because of their natural functional characteristics, involving inter- and intramolecular electron transfer, metalloproteins are good candidates for biomolecular nanoelectronics. In particular, blue copper proteins, such as azurin, can bind gold via a disulfide site present on its surface and they have a natural electron transfer activity that can be exploited for the realization of molecular switches whose conduction state can be controlled by tuning their redox state through an external voltage source. We report on the implementation of a prototype of protein transistor operating in air and in the solid state, based on this class of proteins. The three terminal devices exhibit various functions depending on the relative source-drain and gate-drain voltages bias, opening a way to the implementation of a new generation of logic architectures

Self-chemisorption of azurin on functionalized oxide surfaces for the implementation of biomolecular devices

Abstract In this work, we investigate the formation of redox protein Azurin (Az) monolayers on functionalized oxygen exposing surfaces. These metallo-proteins mediate electron transfer in the denitrifying chain of Pseudomonas bacteria and exhibit self-assembly properties, therefore they are good candidates for bio-electronic applications. Azurin monolayers are self-assembled onto silane functionalized surfaces and characterized by atomic force microscopy (AFM). We show also that a biomolecular field effect transistor (FET) in the solid state can be implemented by interconnecting an Azurin monolayer immobilized on SiO 2 with two gold nanoelectrodes. Transport experiments, carried out at room temperature and ambient pressure, show FET behavior with conduction modulated by the gate potential

Conformation of microcontact-printed proteins by atomic force microscopy molecular sizing.

We investigated the structural changes occurring in proteins patterned via microcontact printing. This was done by molecular sizing using atomic force microscopy to observe the structure of printed individual metalloprotein molecules in the unlabeled and untreated states. We observed that the size of the printed proteins were more than 2-fold smaller than the native shape, which indicates that some deformations take place upon the contact-assisted adsorption on silanized silicon dioxide. This can be attributed to simultaneously occurring effects, and particularly to the sandwiching between surfaces of very different hydrophilic/hydrophobic properties during contact lithography

Generic perturbations of linear integrable Hamiltonian systems

In this paper, we investigate perturbations of linear integrable Hamiltonian systems, with the aim of establishing results in the spirit of the KAM theorem (preservation of invariant tori), the Nekhoroshev theorem (stability of the action variables for a finite but long interval of time) and Arnold diffusion (instability of the action variables). Whether the frequency of the integrable system is resonant or not, it is known that the KAM theorem does not hold true for all perturbations; when the frequency is resonant, it is the Nekhoroshev theorem which does not hold true for all perturbations. Our first result deals with the resonant case: we prove a result of instability for a generic perturbation, which implies that the KAM and the Nekhoroshev theorem do not hold true even for a generic perturbation. The case where the frequency is non-resonant is more subtle. Our second result shows that for a generic perturbation, the KAM theorem holds true. Concerning the Nekhrosohev theorem, it is known that one has stability over an exponentially long interval of time, and that this cannot be improved for all perturbations. Our third result shows that for a generic perturbation, one has stability for a doubly exponentially long interval of time. The only question left unanswered is whether one has instability for a generic perturbation (necessarily after this very long interval of time)

Multiparametric Whole Blood Dissection: A one-shot comprehensive picture of the human hematopoietic system

Human hematopoiesis is a complex and dynamic system where morphologically and functionally diverse mature cell types are generated and maintained throughout life by bone marrow (BM) Hematopoietic Stem/Progenitor Cells (HSPC). Congenital and acquired hematopoietic disorders are often diagnosed through the detection of aberrant frequency or composition of hematopoietic cell populations. We here describe a novel protocol, called “Whole Blood Dissection” (WBD), capable of analyzing in a single test‐tube, hematopoietic progenitors and all major mature cell lineages composing either BM or peripheral blood (PB) through a multiparametric flow‐cytometry analysis. WBD allows unambiguously identifying in the same tube up to 23 different blood cell types including HSPC subtypes and all the major myeloid and lymphoid lineage compartments at different stages of maturation, through a combination of 17 surface and 1 viability cell markers. We assessed the efficacy of WBD by analyzing BM and PB samples from adult (n = 8) and pediatric (n = 9) healthy donors highlighting age‐related shift in cell composition. We also tested the capability of WBD on detecting aberrant hematopoietic cell composition in clinical samples of patients with primary immunodeficiency or leukemia unveiling expected and novel hematopoietic unbalances. Overall, WBD allows unambiguously identifying >99% of the cell subpopulations composing a blood sample in a reproducible, standardized, cost‐, and time‐efficient manner. This tool has a wide range of potential pre‐clinical and clinical applications going from the characterization of hematopoietic disorders to the monitoring of hematopoietic reconstitution in patients after transplant or gene therapy

Personalized Medicine in Gastrointestinal Stromal Tumor (GIST): Clinical Implications of the Somatic and Germline DNA Analysis

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. They are characterized by gain of function mutations in KIT or PDGFRA tyrosine kinase receptors, with their consequent constitutive activation. The gold standard therapy is imatinib that offers a good and stable response for approximately 18-36 months. However, resistance is very common and it is vital to identify new biomarkers. Up until now, there have been two main approaches with focus to characterize novel targets. On the one hand, the focus is on the tumor genome, as the final clinical outcome depends mainly from the cancer specific mutations/alterations patterns. However, the germline DNA is important as well, and it is inconceivable to think the patients response to the drug is not related to it. Therefore the aim of this review is to outline the state of the art of the personalized medicine in GIST taking into account both the tumor DNA (somatic) and the patient DNA (germline)

Therapeutic Drug Monitoring of Imatinib in Gist Patients

n/