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1.
Adv Healthc Mater ; 3(1): 59-68, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23868871

RESUMO

Stable pH is an established biomarker of health, relevant to all tissues of the body, including the heart. Clinical monitoring of pH in a practical manner, with high spatiotemporal resolution, is particularly difficult in organs such as the heart due to its soft mechanics, curvilinear geometry, heterogeneous surfaces, and continuous, complex rhythmic motion. The results presented here illustrate that advanced strategies in materials assembly and electrochemical growth can yield interconnected arrays of miniaturized IrOx pH sensors encapsulated in thin, low-modulus elastomers to yield conformal monitoring systems capable of noninvasive measurements on the surface of the beating heart. A thirty channel custom data acquisition system enables spatiotemporal pH mapping with a single potentiostat. In vitro testing reveals super-Nernstian sensitivity with excellent uniformity (69.9 ± 2.2 mV/pH), linear response to temperature (-1.6 mV °C(-1) ), and minimal influence of extracellular ions (<3.5 mV). Device examples include sensor arrays on balloon catheters and on skin-like stretchable membranes. Real-time measurement of pH on the surfaces of explanted rabbit hearts and a donated human heart during protocols of ischemia-reperfusion illustrate some of the capabilities. Envisioned applications range from devices for biological research, to surgical tools and long-term implants.


Assuntos
Eletrônica , Miocárdio/metabolismo , Animais , Cateterismo Cardíaco , Desenho de Equipamento , Humanos , Concentração de Íons de Hidrogênio , Íons/química , Íons/metabolismo , Isquemia/metabolismo , Isquemia/patologia , Microeletrodos , Miocárdio/química , Próteses e Implantes , Coelhos , Reperfusão , Temperatura
2.
Proc Natl Acad Sci U S A ; 109(49): 19910-5, 2012 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-23150574

RESUMO

Curved surfaces, complex geometries, and time-dynamic deformations of the heart create challenges in establishing intimate, nonconstraining interfaces between cardiac structures and medical devices or surgical tools, particularly over large areas. We constructed large area designs for diagnostic and therapeutic stretchable sensor and actuator webs that conformally wrap the epicardium, establishing robust contact without sutures, mechanical fixtures, tapes, or surgical adhesives. These multifunctional web devices exploit open, mesh layouts and mount on thin, bio-resorbable sheets of silk to facilitate handling in a way that yields, after dissolution, exceptionally low mechanical moduli and thicknesses. In vivo studies in rabbit and pig animal models demonstrate the effectiveness of these device webs for measuring and spatially mapping temperature, electrophysiological signals, strain, and physical contact in sheet and balloon-based systems that also have the potential to deliver energy to perform localized tissue ablation.


Assuntos
Materiais Biocompatíveis , Eletrônica Médica/instrumentação , Técnicas Eletrofisiológicas Cardíacas/instrumentação , Coração/fisiologia , Pericárdio/anatomia & histologia , Próteses e Implantes , Animais , Cateteres , Eletrônica Médica/métodos , Desenho de Equipamento/métodos , Coração/anatomia & histologia , Teste de Materiais , Nanotecnologia/métodos , Coelhos , Semicondutores , Seda , Temperatura
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