Biomedical subjects

S Lazare

Publications and source records attributed to S Lazare.

4 recordsLinked to original sources

PubMed2006

Effect of laser modified surface microtopochemistry on endothelial cell growth.

The introduction of microelectronics technology in the area of biological sciences has brought forth previously unforeseeable applications such as DNA or protein biochips, miniaturized, multiparametric biosensors for high performance multianalyte assays, DNA sequencing, biocomputers, and substrates for controlled cell growth (i.e. tissue engineering). We developed and investigated a new method using "cold" excimer laser beam technology combined with microlithographical techniques to create surfaces with well defined 3D microdomains in order to delineate critical microscopic surface features governing cell-material interactions. Microfabricated surfaces with microgrooves 30-3 microm deep, 10 - 1 microm wide spaced 30 microm apart were obtained with micron resolution, by "microsculpturing" polymer model surfaces using a computer controlled laser KrF excimer beam coupled with a microlithographic projection technique. The laser beam after exiting a mask was focused onto the polymer target surface via an optical setup allowing for a 10-fold reduction of the mask pattern. Various 3D micropatterned features were obtained at the micron level. Reproducible submicron features could also be obtained using this method. Subsequently, model human umbilical endothelial cells (HUVEC) were cultured on the laser microfabricated surfaces in order to study the effects of specific microscopic surface features on cell deposition and orientation. Cell deposition patterns were found to be microstructure dependant, and showed cell orientation dependency for features in the cell range dimension, a behaviour significantly different from that of a previously studied cell model (osteoprogenitor cell). This model may be a promising in so far as it is very rapid (a time frame less than a second per square centimeter of micropatterned surface) and provides further insights into the effects of surface microtopography on cell response with possible applications in the field of biosensors, biomedical and/or pharmaceutical engineering sciences.

Cell Culture Techniques↗

PubMed2005

Grafted self-assembled monolayers derived from naturally occurring phenolic lipids.

Self-assembled monolayers grafted onto silicon surfaces were obtained from the hydrosilylation products by trialcoxysilanes of naturally occurring phenolic lipid allyl ethers. The as-obtained materials were characterized by various physical and physicochemical methods. Thus, contact angles of water drops showed that they possess very high hydrophobicity. Their excellent regularity was corroborated by AFM microscopy. The frequencies of the stretching CH2 infrared modes indicate the presence of alkyl chains mainly in the trans/trans conformation. Additionally, optical ellipsometry and quartz microbalance measurements enabled us to estimate the thickness of the films. The results, as a whole, are in good agreement with the formation of densely packed monolayers.

Adsorption↗

PubMed2002

Laser microfabricated model surfaces for controlled cell growth.

The relatively recent applications of microelectronics technology into the biological sciences arena has drastically revolutionized the field. New foreseeable applications include miniaturized, multiparametric biosensors for high performance multianalyte assays or DNA sequencing, biocomputers, and substrates for controlled cell growth (i.e. tissue engineering). The objectives of this work were to investigate a new method combining microphotolithographical techniques with laser excimer beam technology to create surfaces with well defined 3-D microdomains in order to delineate critical microscopic surface features governing material-cell interaction. Another obvious application of this study pertains to the fabrication of cell-based biosensors. Microfabricated surfaces were obtained with micron resolution, by "microsculpturing" polymer model surfaces using a laser excimer KrF beam coupled with a microlithographic projection technique. The laser beam after exiting a mask was focused onto the polymer target surface via an optical setup allowing for a 10-fold reduction of the mask pattern. Various 3-D micropatterned features were obtained at the micron level. Reproducible submicron features could also be obtained using this method. Subsequently, model osteoblast-like cells were plated onto the laser microfabricated surfaces in order to study the effects of particular surface microtopography on preferential cell deposition and orientation. Preferential cell deposition was observed on surfaces presenting "smooth" microtopographical transitions. This system may provide an interesting model for further insights into correlations between 3-D surface microtopography and cell response with new applications in the field biosensor, biomaterial and pharmaceutical engineering sciences (e.g. new cell based biosensors, controlled synthesis of immobilized cell derived active ingredients).

Biocompatible Materials↗

PubMed1979

Quality assurance strategies in U.S. and Canadian psychiatry.

Quality Assurance Strategies in Psychiatry and Medicine in general have developed rapidly and have been applied widely in the last few years, particularly in the United States. This paper reviews some of those developments both from a methodological and a socio-political point of view. The relevance to the Canadian scene is evaluated, and it is concluded that, although quality assurance is now accepted as an obligation of the health profession, some of the strategies being widely applied in the United States are of questionable value in themselves, and some, particularly cost control techniques, would seem to be irrelevant to the Canadian health field which already has a variety of checks and balances in its universal health insurance system. Though cost control and quality control logically overlap, at times they are allowed to merge and cause conceptual confusion. Finally, as systems are developed in Canada, it is suggested that a means of self-assessment be built in so that the validity and reliability are not in doubt.

Accreditation↗