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Articles 1 - 7 of 7

Full-Text Articles in Engineering

Materials For Diabetes Therapeutics, Kaitlin M. Bratlie, Roger L. York, Michael A. Invernale, Robert Langer, Daniel G. Anderson Jan 2012

Materials For Diabetes Therapeutics, Kaitlin M. Bratlie, Roger L. York, Michael A. Invernale, Robert Langer, Daniel G. Anderson

Kaitlin M. Bratlie

This review is focused on the materials and methods used to fabricate closedloop systems for type 1 diabetes therapy. Herein, we give a brief overview of current methods used for patient care and discuss two types of possible treatments and the materials used for these therapies-(i) artificial pancreases, comprised of insulin producing cells embedded in a polymeric biomaterial, and (ii) totally synthetic pancreases formulated by integrating continuous glucose monitors with controlled insulin release through degradable polymers and glucose-responsive polymer systems. Both the artificial and the completely synthetic pancreas have two major design requirements: the device must be both biocompatible and …


Spatiotemporal Effects Of A Controlled-Release Anti-Inflammatory Drug On The Cellular Dynamics Of Host Response, Tram T. Dang, Kaitlin M. Bratlie, Said R. Bogatyrev, Xiao Chen, Robert Langer, Daniel G. Anderson Jan 2011

Spatiotemporal Effects Of A Controlled-Release Anti-Inflammatory Drug On The Cellular Dynamics Of Host Response, Tram T. Dang, Kaitlin M. Bratlie, Said R. Bogatyrev, Xiao Chen, Robert Langer, Daniel G. Anderson

Kaitlin M. Bratlie

In general, biomaterials induce a non-specific host response when implanted in the body. This reaction has the potential to interfere with the function of the implanted materials. One method for controlling the host response is through local, controlled-release of anti-inflammatory agents. Herein, we investigate the spatial and temporal effects of an anti-inflammatory drug on the cellular dynamics of the innate immune response to subcutaneously implanted poly(lactic-co-glycolic) microparticles. Noninvasive fluorescence imaging was used to investigate the influence of dexamethasone drug loading and release kinetics on the local and systemic inhibition of inflammatory cellular activities. Temporal monitoring of host response showed that …


Dead Zones In Porous Catalysts: Concentration Profiles And Efficiency Factors, Roger L. York, Kaitlin M. Bratlie, Lloyd R. Hile, Larry K. Jang Jan 2011

Dead Zones In Porous Catalysts: Concentration Profiles And Efficiency Factors, Roger L. York, Kaitlin M. Bratlie, Lloyd R. Hile, Larry K. Jang

Kaitlin M. Bratlie

This paper examines the conditions under which a dead zone, or a portion of the catalyst devoid of reactant, can form in a porous catalyst in which simultaneous reaction and diffusion are occurring. The condition that allows for the existence of a dead zone is defined by a critical Thiele modulus. When the Thiele modulus - the ratio of chemical reaction to diffusion - is greater than the critical Thiele modulus, a dead zone exists. This dead zone can be mathematically defined by a change of boundary conditions. We examine nth order reactions in isothermal infinite slabs, infinite cylinders, and …


Development Of Cationic Polymer Coatings To Regulate Foreign-Body Responses, Minglin Ma, Wendy F. Liu, Paulina S. Hill, Kaitlin M. Bratlie, Daniel J. Siegwart, Justin Chin, Miri Park, Joao Guerreiro, Daniel G. Anderson Jan 2011

Development Of Cationic Polymer Coatings To Regulate Foreign-Body Responses, Minglin Ma, Wendy F. Liu, Paulina S. Hill, Kaitlin M. Bratlie, Daniel J. Siegwart, Justin Chin, Miri Park, Joao Guerreiro, Daniel G. Anderson

Kaitlin M. Bratlie

A library of cationic polymers, poly(beta-amino alcohols) with a great chemical diversity are synthesized using combinatorial polymerization. These polymers, when immobilized on a surface, drastically affect the behavior of monocyte/macrophage cells in vitro and early inflammatory reactions in vivo. Certain polymers are found capable of mitigating the foreign-body responses.


Real-Time In Vivo Detection Of Biomaterial-Induced Reactive Oxygen Species, Minglin Ma, Wendy F. Liu, Kaitlin M. Bratlie, Tram Dang, Robert Langer, Daniel G. Anderson Jan 2011

Real-Time In Vivo Detection Of Biomaterial-Induced Reactive Oxygen Species, Minglin Ma, Wendy F. Liu, Kaitlin M. Bratlie, Tram Dang, Robert Langer, Daniel G. Anderson

Kaitlin M. Bratlie

The non-specific host response to implanted biomaterials is often a key challenge of medical device design. To evaluate biocompatibility, measuring the release of reactive oxygen species (ROS) produced by inflammatory cells in response to biomaterial surfaces is a well-established method. However, the detection of ROS in response to materials implanted in vivo has not yet been demonstrated. Here, we develop a bioluminescence whole animal imaging approach to observe ROS released in response to subcutaneously-implanted materials in live animals. We compared the real-time generation of ROS in response to two representative materials, polystyrene and alginate, over the course of 28 days. …


Microfabrication Of Homogenous, Asymmetric Cell-Laden Hydrogel Capsules, Qiaobing Xu, Tram T. Dang, Kaitlin M. Bratlie, Ivy Chen, Robert Langer, Daniel G. Anderson Jan 2009

Microfabrication Of Homogenous, Asymmetric Cell-Laden Hydrogel Capsules, Qiaobing Xu, Tram T. Dang, Kaitlin M. Bratlie, Ivy Chen, Robert Langer, Daniel G. Anderson

Kaitlin M. Bratlie

Cell encapsulation has been broadly investigated as a technology to provide immunoprotection for transplanted endocrine cells. Here we develop a new fabrication method that allows for rapid, homogenous microencapsulation of insulin-secreting cells with varying microscale geometries and asymmetrically modified surfaces. Micromolding systems were developed using polypropylene mesh, and the material/surface properties associated with efficient encapsulation were identified. Cells encapsulated using these methods maintain desirable viability and preserve their ability to proliferate and secrete insulin in a glucose-responsive manner. This new cell encapsulation approach enables a practical route to an inexpensive and convenient process for the generation of cell-laden microcapsules without …


A Reactive Oxide Overlayer On Rhodium Nanoparticles During Co Oxidation And Its Size Dependence Studied By In Situ Ambient-Pressure X-Ray Photoelectron Spectroscopy, Michael E. Grass, Hendrik Bluhm, Yawen Zhang, Derek Butcher, Jeong Y. Park, Yimin Li, Kaitlin M. Bratlie, Tianfu Zhang, Gabor A. Somorjai Jan 2008

A Reactive Oxide Overlayer On Rhodium Nanoparticles During Co Oxidation And Its Size Dependence Studied By In Situ Ambient-Pressure X-Ray Photoelectron Spectroscopy, Michael E. Grass, Hendrik Bluhm, Yawen Zhang, Derek Butcher, Jeong Y. Park, Yimin Li, Kaitlin M. Bratlie, Tianfu Zhang, Gabor A. Somorjai

Kaitlin M. Bratlie

The smaller, the better: In situ synchrotron ambient pressure X-ray photoelectron spectroscopy allows examination of the oxidation state of the surface of the rhodium nanoparticles (NPs) during CO oxidation in an O2 atmosphere. 2 nm NPs oxidize to a larger extent than 7 nm NPs during reaction at 150-200°C, which correlates with a fivefold increase in turnover frequency for the smaller nanoparticles.