Materials and Design Approaches for a Fully Bioresorbable, Electrically Conductive and Mechanically Compliant Cardiac Patch Technology.

Myocardial infarction (MI) is one of the leading causes of death and disability. Recently developed cardiac patches provide mechanical support and additional conductive paths to promote electrical signal propagation in the MI area to synchronize cardiac excitation and contraction. Cardiac patches based on conductive polymers offer attractive features; however, the modest levels of elasticity and high impedance interfaces limit their mechanical and electrical performance. These structures also operate as permanent implants, even in cases where their utility is limited to the healing period of tissue damaged by the MI. The work presented here introduces a highly conductive cardiac patch that combines bioresorbable metals and polymers together in a hybrid material structure configured in a thin serpentine geometry that yields elastic mechanical properties. Finite element analysis guides optimized choices of layouts in these systems. Regular and synchronous contraction of human induced pluripotent stem cell-derived cardiomyocytes on the cardiac patch and ex vivo studies offer insights into the essential properties and the bio-interface. These results provide additional options in the design of cardiac patches to treat MI and other cardiac disorders.

Bioresorbable Metals for Biomedical Applications: From Mechanical Components to Electronic Devices.

Bioresorbable metals and metal alloys are of growing interest for myriad uses in temporary biomedical implants. Examples range from structural elements as stents, screws, and scaffolds to electronic components as sensors, electrical stimulators, and programmable fluidics. The associated physical forms span mechanically machined bulk parts to lithographically patterned conductive traces, across a diversity of metals and alloys based on magnesium, zinc, iron, tungsten, and others. The result is a rich set of opportunities in healthcare materials science and engineering. This review article summarizes recent advances in this area, starting with an historical perspective followed by a discussion of materials options, considerations in biocompatibility, and device applications. Highlights are in system level bioresorbable electronic platforms that support functions as diagnostics and therapeutics in the context of specific, temporary clinical needs. A concluding section highlights challenges and emerging research directions.

Control of Skin Potential by Triboelectrification with Ferroelectric Polymers.

Negatively polarized ferroelectric polymer ß-P(VDF-TrFE) shows higher positive triboelectric properties than skin, which could lead to new medical applications. Kelvin force microscope measurements and triboelectric nanogenerator characterizations are performed to demonstrate this new property. In addition, how many negative charges are exchanged by contact electrification between the negatively polarized ß-P(VDF-TrFE) and the skin is estimated.