Biomedicine

Summary

Biomedicine (also referred to as Western medicine, mainstream medicine or conventional medicine) is a branch of medical science that applies biological and physiological principles to clinical practice. Biomedicine stresses standardized, evidence-based treatment validated through biological research, with treatment administered via formally trained doctors, nurses, and other such licensed practitioners. Biomedicine also can relate to many other categories in health and biological related fields. It has been the dominant system of medicine in the Western world for more than a century. It includes many biomedical disciplines and areas of specialty that typically contain the "bio-" prefix such as molecular biology, biochemistry, biotechnology, cell biology, embryology, nanobiotechnology, biological engineering, laboratory medical biology, cytogenetics, genetics, gene therapy, bioinformatics, biostatistics, systems biology, neuroscience, microbiology, virology, immunology, parasitology,

Official source

https://en.wikipedia.org/wiki/Biomedicine

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (11)

Related publications

Related people

Related units

Related concepts (18)

Related concepts

Related courses (11)

Related courses

Related lectures (5)

Related lectures

Hydrophilic nanocarriers, formed by electrostatic interaction between their oppositely charged components, are recognized as nanomaterials with an enormous potential as vectors in biomedical and pharmaceutical applications. However, comprehensive information about their fate in various biological environments is still lacking. In general, due to their size, nanoparticles are able to enter and transport molecules into cells via pathways forbidden for bigger structures of even identical chemical nature. Research under defined conditions aiming at a better understanding of nanoparticle-cell interactions is crucial for the development of safe and successful nanocarriers for biomedical and pharmaceutical applications. Nanogels produced by electrostatic interaction of two types of the polysaccharide chitosan and pentasodium triphosphate were the subject of the research of this thesis. Additional surface coating with sodium alginate conferred to the nanogels a negatively charged surface enabling sufficient stability under physiological and in vivo relevant conditions. Of particular interest was the comparison of the two chitosan types, the first one obtained from usual animal sources while the second one became newly available from fungal sources. Prerequisite for the comparison in terms of nanogel formation, stability, interaction with cells and potential applications was the detailed analysis and characterization of the chitosan samples. The identification of almost identical degree of deacetylation, very similar molar mass distribution and solution behavior, but a somewhat higher molar mass of the animal chitosan as the only difference, allowed for a direct comparison. The animal and fungal derived chitosan samples yielded similar nanogels in relation to formation, size distributions and zeta potential. The nanogels were spherical with a hydrodynamic diameter in the range of 450 nm and a zeta potential of approx. -65 mV. The physical characteristics of the nanogels were clearly influenced by the ionic strength and temperature of the suspension. High deformability of the nanogel network was demonstrated by filtration through pores much narrower than the gel diameter. Temperature cycles in the range of 4°C to 37°C proved reversibility of size and zeta potential. The nanogels were stable in both simulated in vivo environment and in conditioned cell culture media. Exposure of seven human cancerous and non-cancerous cell lines to the nanogels, to identify the influence on the cell metabolic activity, revealed cell-type, nanogel dosage and exposure time dependence. However, nanogels prepared from animal and fungal chitosan showed similar behavior in vitro in all cell lines tested. The results obtained so far confirm fungal derived chitosan as an alternative to the animal derived chitosan. Nanogels carrying model protein antigen cargoes were taken up by porcine monocyte-derived dendritic cells, and kinetic analysis using an auto-quenched protein revealed a time-dependent endocytic processing of the nanogel cargo. These in vitro analyses were elaborated with an in vivo murine immunization experiment. Nanogels carrying ovalbumin (OVA) induced a dose-dependent antibody response over 6 weeks post-vaccination. An effective memory response was induced in nanogel-OVA immunized mice following a 0.1 µg OVA boost injection. Nanogels were also prepared carrying recombinant vaccine antigen against Neospora caninum. These induced a protective immune response following both intranasal and intraperitoneal vaccination in mice challenged with the tachyzoite form of the parasite. Overall, the results obtained in the framework of this research extend the knowledge on chitosan-based nanogels intended as nanocarriers for biomedical/pharmaceutical applications and contribute to further development of effective nanogel-based delivery systems.

EPFL2011

'Green' Cr(III)-based electrodeposition of stainless steel-like FeCrNi: synthesis, mechanisms, material properties of films and micro-nanocomponents for bio-medical applications

Enrico Bertero

The electrodeposition (ED) of stainless steel (SS) -like FeCrNi alloys for miniaturised devices is appealing for bio-medicine as it would allow combining excellent material properties (e.g. corrosion resistance, hardness, bio-compatibility) at low-cost. However, conventional baths often contain hazardous Cr(VI). Alloys ED from environmentally friendly Cr(III) electrolytes is crucial for facilitating the transition towards sustainable and ecological production. Still, this process was not comprehensively studied. ED from Cr(III)-based aqueous electrolytes leads to impurities incorporated in films, hydrogen evolution reaction (HER) and side-effects. The role of both electrolyte composition, containing organic additives (e.g. glycine), and deposition parameters on material properties was not clear. Moreover, passing from films to micro-nanocomponents (M-NEMS) via ED was not properly investigated when dealing with more complex Cr(III)-based alloys. The aim of this thesis has been to study the ED of FeCrNi coatings and M-NEMS using a 'green' Cr(III)-glycine electrolyte, understanding better the relations between ED mechanisms, deposition parameters and material properties, as well as their variation due to miniaturisation. Novel information was attained for all-aqueous electrolytes by investigating: films microstructure evolution (amorphous-nanocrystalline) in correlation to their composition and elemental 3D distribution, influence of Cr(III)-glycine in terms of coatings at%, together with a thorough analysis on metals speciation/complexation in the baths. These results allowed to propose various Cr(III)-based ED mechanisms. The material properties of the as-deposited films were evaluated in dependence of morphology and composition variations, then compared to the standard metallurgical ones. FeCrNi electrodeposits showed good passivation and bio-compatibility comparable to AISI SS, and tuneable soft-magnetism. However, tribological tests revealed that the material was hard but brittle. The main issues were correlated to HER leading to low deposition efficiency, material brittleness and porosity. To overcome these issues, a mixed-solvent electrolyte composed of ethylene glycol (EG) has been investigated and compared to the all-aqueous one, showing similar Cr(III)-glycine complexation, but higher deposition efficiency (decrease in HER). EG-based electrolyte was found to be an effective solution for obtaining FeCrNi M-NEMS via template assisted ED. Nanotubes (NTs) and nanowires (NWs) have been achieved via ED into AAO templates: high currents resulted in NTs, whereas low ones in compact NWs. Micro-pillars have been created via ED into UV-LIGA moulds, combining EG-based electrolyte and a CV-like deposition, avoiding moulds delamination caused by HER and under-deposition. A comparison of the material properties was pursued for FeCrNi electrodeposits as-deposited (amorphous) and annealed (nanocrystalline) for both studied electrolytes. This investigation correlated electrolyte type, material composition/microstructure/morphology, vs. other material properties i.e. corrosion resistance, bio-compatibility, magnetic and mechanical properties. In conclusion, this research studied in depth Cr(III)-based ED, achieving improvements and giving useful guidelines for applying this process for creating SS-like coatings and M-NEMS for advanced bio-medical applications.

EPFL2020

Mechanochemically Responsive Surfaces and Soft Tissue Adhesive Interfaces Generated via Controlled Radical Polymerization

Nariye Cavusoglu Ataman

Thin coatings applied to surfaces dramatically improve the properties of materials. Thus, they have found application in a broad variety of areas including biomedicine, nanotechnology, bioelectronics and optics, amongst others. Polymer brushes prepared via surface-initiated controlled radical polymerization (SI-CRP) techniques represent a versatile class of thin polymer coatings that provide manifold opportunities to engineer surface and interface properties. Densely grafted polymer brushes prepared via SI-CRP possess several attractive material properties such as low friction coefficients and the ability to prevent biofouling, which are related to the stretched conformation of the surface tethered polymer chains. Those distinctive characteristics of polymer brushes make them highly appealing to engineer the properties of functional interfaces. A first aim of this Thesis is to investigate the mechanochemistry of hydrophilic polymer brushes prepared via surface-initiated atom transfer radical polymerization (SI-ATRP) from silica substrates. The second aim of the Thesis is to explore poly(2-hydroxyethyl methacrylate) (PHEMA) based polymer brushes as soft-tissue adhesives in wet tissue environment. This Thesis is divided into four chapters, which are briefly summarized below. Chapter 1 provides a summary of recent literature that has reported detachment or degrafting of densely grafted hydrophilic polymer brushes from substrates upon exposure to aqueous media. The collective results from these reports suggest that swelling-induced stretching of hydrophilic polymer brushes lead to mechanochemical activation of the bonds near the brush-substrate interface and subsequently facilitates hydrolytic chain cleavage. Chapter 2 aims to shed light on the influence of two fundamental structural polymer brush parameters on the degrafting of surface-tethered, densely grafted polymer chains, viz. (i) the chemical composition of the ATRP initiator that is used to grow the polymer brushes and (ii) the effect of surface curvature. To this end, a series of poly(poly(ethylene glycol) methacrylate) (PPEGMA) and poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMEMA) brushes were grafted from both flat silica substrates as well as silica nanoparticles. Subsequently, the degrafting of the surface-tethered polymer chains was investigated in cell culture medium and phosphate buffered saline (PBS) using various techniques. The aim of the final two Chapters of this Thesis is less on exploring the chain conformation of polymer chains grafted by SI-CRP, but more to use the ability of SI-CRP to prepare thin polymer films that present a high surface concentration of functional groups to mediate soft tissue adhesion. Chapter 3 describes the preparation of photo-active poly(2-hydroxyethyl methacrylate) (PHEMA) brushes as soft tissue bioadhesives. Tissue adhesion in this Chapter is induced as UV-irradiation of PHEMA brushes converts the initially bio-inert side chain hydroxyl groups of these brushes into (putatively) aldehyde groups, which can react with amine groups present in the tissue. The prepared PHEMA brush coated substrates are biocompatible, which avoids fibrous capsule formation and presents functionalities that can be transformed, on-demand, from a non-reactive, non-adhesive state to a reactive, adhesive state in wet tissue environment. While the photoactivation of the PHEMA side chain functional groups is very efficient, it is not very well defined from a chemistry point of view. Chapter 4 therefore, explores an alternative photoactivation chemistry, which is based on the use of the diazirine motif. These diazirine motifs were incorporated in poly(2-hydroxyethyl methacrylate-co-poly(ethylene glycol) methyl ether methacrylate) (P(HEMA-co-PEGMEMA)) copolymer brushes via post-polymerization modification. These diazirine modified brushes are attractive as they may not only be activated by UV-light but also by electrochemical means.

EPFL2016