Kyle R Fenton

Biomimetic Silica Microspheres in Biosensing

Lipid vesicles spontaneously fuse and assemble into a lipid bilayer on planar or spherical silica surfaces and other substrates. The supported lipid bilayers (SLBs) maintain characteristics of biological membranes, and are thus considered to be biomembrane mimetic systems that are stable because of the underlying substrate. Examples of their shared characteristics with biomembranes include lateral fluidity, barrier formation to ions and molecules, and their ability to incorporate membrane proteins into them. Biomimetic silica microspheres consisting of SLBs on solid or porous silica microspheres have been utilized for different biosensing applications. The advantages of such biomimetic microspheres for biosensing include their increased surface area to volume ratio which improves the detection limits of analytes, and their amenability for miniaturization, multiplexing and high throughput screening. This review presents examples and formats of using such biomimetic solid or porous silica microspheres in biosensing.

Biosensors based on release of compounds upon disruption of lipid bilayers supported on porous microspheres

The authors describe a biosensing concept based on the release of compounds, which are encapsulated within lipid-coated porous silica microspheres, by detergents and toxins that disrupt supported lipid bilayers SLBs on the microspheres. Suspension and microfluidic based methods have been developed to monitor the release of the encapsulated compounds in response to membrane disruption. The authors established that the SLBs on porous microspheres can endure experimental conditions necessary for their incorporation into packed microchannels while maintaining the bilayer integrity and functionality. Model compounds including a nonionic detergent Triton X-100, a membrane active protein (α-hemolysin, and a membrane lytic antimicrobial peptide melittin were successfully utilized to interact with different formulations of SLBs on porous silica microspheres. The results demonstrate the stability of the SLBs on the microspheres for several weeks, and the feasibility of using this system to detect the release of fluorescent dyes as well as other molecular reporters. The latter were detected by their involvement in subsequent biospecific interactions that were detected by fluorescence. This study exemplifies proof of concept for developing new chemical and biochemical sensors and drug delivery systems based on the disruption of lipid membranes coating porous silica microspheres that encapsulate dyes or bioactive compounds.

Advanced inactive materials for improved lithium-ion battery safety.

This report describes advances in lithium-ion battery safety by use of alternative electrolytes and separators. Electrolytes based on hydrofluoro ether solvents and sulfonimide salts were characterized to determine electrochemical performance, thermal stability, and decomposition products. Flammability of these electrolytes was also tested under known cell failure mode conditions. Separators based on high melting temperature polymers and ceramics were developed by fiber spinning, casting, and vapor deposition techniques. Resulting high melt integrity separators show good electrochemical performance and improved thermal stability compared to commercial polyolefin separator materials.

Abuse Tolerance Improvements.

As lithium-ion battery technologies mature, the size and energy of these systems continues to increase (> 50 kWh for EVs); making safety and reliability of these high energy systems increasingly important. While most material advances for lithium-ion chemistries are directed toward improving cell performance (capacity, energy, cycle life, etc.), there are a variety of materials advancements that can be made to improve lithium-ion battery safety. Issues including energetic thermal runaway, electrolyte decomposition and flammability, anode SEI stability, and cell-level abuse tolerance continue to be critical safety concerns. This report highlights work with our collaborators to develop advanced materials to improve lithium-ion battery safety and abuse tolerance and to perform cell-level characterization of new materials.