Printing of “organic electronics” using 3D technology

Microscale organic electronics that may be utilised in bioelectronics through the usage of multiphoton 3D printers

Mohammad Reza Abidian, an associate professor of Biomedical Engineering at the University of Houston Cullen College of Engineering, sees the potential for the use of multiphoton 3-D printers in flexible electronics and bioelectronics when he considers the future of the production of micro-scale organic electronics.

The most recent study that came out of his research group investigates the potential applications of such technology. In the journal Advanced Materials, an article titled “Multiphoton Lithography of Organic Semiconductor Devices for 3D Printing of Flexible Electronic Circuits, Biosensors, and Bioelectronics” was recently published online.

The 3D printing of electronics has become a promising technology over the past few years due to their potential uses in new fields such as nanoelectronics and nanophotonics. These domains are only beginning to emerge as areas of study. In the realm of 3D microfabrication technologies, multiphoton lithography, also known as MPL, is regarded as the most advanced microfabrication method due to its true 3D fabrication capability, excellent level of spatial and temporal control, and the versatility of photosensitive materials, the majority of which are composed of acrylate-based polymers or monomers or epoxy-based photoresists.

Abidian stated that they have “developed a novel photosensitive resin doped with an organic semiconductor material (OS) in this article” in order to “fabricate highly conductive 3D microstructures with high-quality structural features using the MPL technique.”

They demonstrated that the manufacturing process could be carried out on glass in addition to flexible polymer substrates (dimethylsilosane). They found that loading the resin with as little as 0.5 weight percent OS significantly enhanced the electrical conductivity of printed organic semiconductor composite polymer by more than 10 orders of magnitude.

According to Abidian, “the great electrical conductivity may be due to the presence of OS in the cross-linked polymer chains. This presence of OS provides both ionic and electronic conduction routes along the polymer chains, which results in the outstanding electrical conductivity.”

His team fabricated a variety of microelectronic devices in order to demonstrate the potential electronic applications that could be based on the OS composite resin. These microelectronic devices include a micro-printed circuit board, which is comprised of a variety of electrical elements, as well as an array of microcapacitors.

The bioprinting of organic semiconductor microdevices in three dimensions using MPL has the potential to be used in a variety of biomedical applications, such as tissue engineering, bioelectronics, and biosensors. The team led by Abidian was successful in incorporating bioactive molecules into the OS composite microstructures. These molecules included laminin and glucose oxidase (OSCMs). Primary mouse endothelial cells were cultivated on OS composite microstructures with the purpose of determining whether or not the bioactivity of laminin had been preserved throughout the entirety of the MPL process. Cells that had been seeded onto laminin-incorporated OSCMs showed signs of adhesion to the substrate, increased proliferation, and improved survival.

“We also tested the biocompatibility of the OS composite structures by cultivating lymphocytes, specifically splenic T-cells and B-cells, on the fabricated surfaces and contrasting them with control surfaces. This allowed us to determine whether or not the OS composite structures were suitable for human use. After seven days of growth, OS composite polymers did not promote cell death, showing nearly the same level of cell viability as the control surfaces, which was around 94% “Abidian remarked. “In addition to this, research was done to investigate the possible effects of OS composite polymers on cell activation. After seven days of culture, there was no discernible difference in the expression of activation markers on the lymphocytes between OS composite structures and control surfaces. This was the case even though there was a large amount of overlap between the two groups.”

In conclusion, Abidian suggested a maskless process for fabricating bioelectronics and biosensors that was based on MPL. They created a glucose biosensor that was analogous to brain electrodes designed in the Michigan approach. Through the use of the MPL technique, the enzyme glucose oxidase, which is responsible for the particular identification of glucose, was encapsulated inside of the solidified OS composite microelectrodes. When compared to glucose biosensors that came before it, this biosensor presented a glucose sensing platform that was extremely sensitive and had about ten times the sensitivity of other glucose biosensors. In addition to that, this biosensor demonstrated a high level of repeatability and great specificity.

“We anticipate that the presented MPL-compatible OS composite resins will pave the path towards production of soft, bioactive, and conductive microstructures for various applications in the emerging fields of flexible bioelectronics, biosensors, nanoelectronics, organ-on-chips, and immune cell therapies,” according to the authors of the study. Abidian said

Former graduate students Omid Dadras-Toussi and Milad Khorrami, as well as postdoctoral researcher Anto Sam Crosslee Louis Sam Titus, contributed to the writing of the work as co-authors. Abidian lauded the efforts of his students in conducting this study and mentioned that Dadras-Toussi will soon be beginning a new position at Medtronic, an S&P 100 firm that generates $30 billion in sales each year. Abidian emphasised that Dadras-Toussi would be starting this month.

Co-authors also include Sheereen Majd, who is an associate professor of Biomedical Engineering, and Chandra Mohan, who is the Hugh Roy and Lillie Cranz Cullen Endowed Professor of Biomedical Engineering at the University of Hawaii Cullen College of Engineering. According to Abidian, his colleagues were important contributors to the research.

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