Fabrication of Ordered Sub-Micron Topographies on Large-Area Poly(Urethane Urea) by Two-Stage Replication Molding

2004 ◽  
Vol 820 ◽  
Author(s):  
Keith R. Milner ◽  
Mallory Balmer ◽  
Henry J. Donahue ◽  
Alan J. Snyder ◽  
Christopher A. Siedlecki
Keyword(s):  
Cell Adhesion ◽  
Surface Chemistry ◽  
Cell Behavior ◽  
Material Surface ◽  
Biological Cell ◽  
Large Area ◽  
Molding Process ◽  
Two Stage ◽  
Cell Material Interactions

AbstractIt has been established that material surface topography can have a significant effect on biological cell adhesion, in the absence of changes in surface chemistry. Such investigations were typically performed using surface features with size on the order of microns, comparable to the dimensions of the cells. It has been demonstrated that sub-micron sized topographies that cannot be created via contact lithography also influence cell behavior. The ability to affect cell adhesion is a prime consideration in the development of novel biomaterials. This study reports a two-stage replication molding process for fabricating ordered sub-micron sized features over a large area of biomedical polyether(urethane urea). Such a technique has great applicability in the area of long-term implantable materials as a method for influencing cell-material interactions.

scholarly journals Mammalian Cell Behavior on Hydrophobic Substrates: Influence of Surface Properties

2019 ◽  
Vol 3 (2) ◽  
pp. 48 ◽  
Author(s):  
Michele Ferrari ◽  
Francesca Cirisano ◽  
M. Carmen Morán
Keyword(s):  
Cell Adhesion ◽  
Surface Chemistry ◽  
Cell Viability ◽  
Surface Charge ◽  
Surface Properties ◽  
Mammalian Cell ◽  
Cell Biology ◽  
Biomedical Applications ◽  
Cell Behavior ◽  
Water Repellent

The influence of different surface properties holding to a modification of the substrate towards hydrophobic or superhydrophobic behavior was reviewed in this paper. Cell adhesion, their communication, and proliferation can be strongly manipulated, acting on interfacial relationship involving stiffness, surface charge, surface chemistry, roughness, or wettability. All these features can play mutual roles in determining the final properties of biomedical applications ranging from fabrics to cell biology devices. The focus of this work is the mammalian cell viability in contact with moderate to highly water repellent coatings or materials and also in combination with hydrophilic areas for more specific application. Few case studies illustrate a range of examples in which these surface properties and design can be fruitfully matched to the specific aim.

scholarly journals NANOPATTERNED INTERFACES FOR CONTROLLING CELL BEHAVIOR

Nano LIFE ◽  
2010 ◽  
Vol 01 (01n02) ◽  
pp. 63-77 ◽  
Author(s):  
KEVIN CHUNG ◽  
JESSICA A. DeQUACH ◽  
KAREN L. CHRISTMAN
Keyword(s):  
Gene Expression ◽  
Cell Adhesion ◽  
Surface Chemistry ◽  
Semiconductor Industry ◽  
Cell Behavior ◽  
Adhesion Receptors ◽  
Cell Responses ◽  
Nanoscale Fabrication

Many studies have demonstrated that microscale changes to surface chemistry and topography affect cell adhesion, proliferation, differentiation, and gene expression. More recently, studies have begun to examine cell behavior interactions with structures on the nanoscale since in vivo, cells recognize and adhere to cell adhesion receptors that are spatially organized on this scale. These studies have been enabled through various fabrication methods, many of which were initially developed for the semiconductor industry. This review explores cell responses to a variety of controlled topographical and biochemical cues using an assortment of nanoscale fabrication methods in order to elucidate which pattern dimensions are beneficial for controlling cell adhesion and differentiation.

scholarly journals Long-term outcomes of two-stage, immediate and delayed breast reconstruction with polyurethane-covered versus textured implants: protocol of a prospective, multicentre randomised controlled trial (TIPI trial)

BMJ Open ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. e044219
Author(s):  
J X Harmeling ◽  
Kevin Peter Cinca ◽  
Eleni-Rosalina Andrinopoulou ◽  
Eveline M L Corten ◽  
M A Mureau
Keyword(s):  
Randomised Controlled Trial ◽  
Breast Reconstruction ◽  
Controlled Trial ◽  
Capsular Contracture ◽  
Tissue Expander ◽  
Complication Rates ◽  
Two Stage ◽  
Randomised Controlled

IntroductionTwo-stage implant-based breast reconstruction is the most commonly performed postmastectomy reconstructive technique. During the first stage, a tissue expander creates a sufficiently large pocket for the definite breast implant placed in the second stage. Capsular contracture is a common long-term complication associated with implant-based breast reconstruction, causing functional complaints and often requiring reoperation. The exact aetiology is still unknown, but a relationship between the outer surface of the implant and the probability of developing capsular contracture has been suggested. The purpose of this study is to determine whether polyurethane-covered implants result in a different capsular contracture rate than textured implants.Methods and analysisThe Textured Implants versus Polyurethane-covered Implants (TIPI) trial is a multicentre randomised controlled trial with a 1:1 allocation rate and a follow-up of 10 years. A total of 321 breasts of female adults undergoing a two-stage breast reconstruction will be enrolled. The primary outcome is capsular contracture at 10-year follow-up which is graded with the modified Baker classification. It is analysed with survival analysis using a frailty model for clustered interval-censored data, with both an intention-to-treat and per-protocol approach. Secondary outcomes are other complication rates, surgical revision rate, patient satisfaction and quality of life and user-friendliness. Outcomes are measured 2 weeks, 6 months, 1, 2, 3, 5 and 10 years postoperatively. Interim analysis is performed when 1-year, 3-year and 5-year follow-up is completed.Ethics and disseminationThe trial has been reviewed and approved by the Medical Research Ethics Committee of the Erasmus MC, University Medical Centre Rotterdam (MEC-2018-126) and locally by each participating centre. Written informed consent will be obtained from each study participant. The results will be disseminated by publication in peer-reviewed journals.Trial registrationNTR7265.

scholarly journals Functionalized Poly(ethylene glycol)-Based Bioassay Surface Chemistry That Facilitates Bio-Immobilization and Inhibits Nonspecific Protein, Bacterial, and Mammalian Cell Adhesion

2007 ◽  
Vol 19 (18) ◽  
pp. 4405-4414 ◽  
Author(s):  
Gregory M. Harbers ◽  
Kazunori Emoto ◽  
Charles Greef ◽  
Steven W. Metzger ◽  
Heather N. Woodward ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Ethylene Glycol ◽  
Surface Chemistry ◽  
Mammalian Cell ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

Surface Cleaning Challenges for Organic Light Emitting Diodes

2021 ◽  
Vol 314 ◽  
pp. 3-8
Author(s):  
Noel Giebink
Keyword(s):  
Light Emitting Diodes ◽  
Surface Cleaning ◽  
Organic Light Emitting Diodes ◽  
Large Area ◽  
Light Emitting ◽  
Organic Light ◽  
Organic Optoelectronic Devices ◽  
Soft Thin Film ◽  
Organic Optoelectronic

Organic optoelectronic devices such as light-emitting diodes and solar cells present unique challenges for surface cleaning and preparation because of their large area and the ‘soft’, thin film nature of the materials involved. This paper gives an introduction to this class of semiconductor devices and covers a recent example of how surface cleaning impacts the long-term reliability of organic light-emitting diodes being commercialized for solid-state lighting.

scholarly journals A two-stage surface treatment for the long-term stability of hydrophilic SU-8

2015 ◽  
Vol 47 (13) ◽  
pp. 1174-1179 ◽  
Author(s):  
Angela Sobiesierski ◽  
Robert Thomas ◽  
Philip Buckle ◽  
David Barrow ◽  
Peter M. Smowton
Keyword(s):  
Surface Treatment ◽  
Two Stage ◽  
Term Stability ◽  
Long Term Stability

Shareholder activism impact on efficiency in Brazil

2019 ◽  
Vol 19 (1) ◽  
pp. 141-157 ◽  
Author(s):  
Paula Guimaraes ◽  
Ricardo P.C. Leal ◽  
Peter Wanke ◽  
Matthew Morey
Keyword(s):  
Shareholder Activism ◽  
Efficiency Score ◽  
Data Envelopment ◽  
Truncated Regression ◽  
Two Stage ◽  
Content Type ◽  
Financial Characteristics ◽  
Long Term Impact ◽  
A Company

Purpose This paper aims to investigate the long-term impact of shareholder activism on Brazilian listed companies. Design/methodology/approach This study uses a sample of 194 companies in 2010, 2012 and 2014 and a two-stage data envelopment analysis to generate an efficiency score based on corporate governance, ownership structure and financial characteristics of companies. In the second stage, the study applies a bootstrap truncated regression to identify whether there is a relationship between the efficiency scores and a company-level activism index. Findings The results show a negative correlation between the efficiency scores and the activism index, suggesting that activist shareholders tend to target less efficient companies. A time analysis over the period 2010-2014 does not offer evidence of impacts of activism on changes of the efficiency scores. Practical implications Activist shareholders target less efficient companies. Shareholder activism increased after regulation that facilitated shareholder voting and required greater company transparency was introduced. Originality/value The two-stage nature of the procedure used in the analysis ascertains that this result is not spurious, assuring data separability between productive resources and contextual variables. This study contributes to the scarce literature on activism in emerging markets.

Sign in / Sign up

Export Citation Format

Share Document