New glues
Berkeley engineers have discovered a new chemical strategy that opens the door to high-performance, recyclable adhesives for a wide variety of applications — including a surgical superglue, a pressure-sensitive adhesive and an epoxy-like structural adhesive.
To develop these new adhesives, the researchers looked to polymers derived from alpha-lipoic acid (αLA), a small molecule that aids in cell metabolism. The instability of αLA polymers has long been a barrier to their use in practical settings, but the team was able to stabilize the αLA polymer, then make small modifications to the underlying monomer composition.
“Most commercially available polymer adhesives are tailored for specific, sometimes narrow uses,” said Phillip Messersmith, professor of bioengineering and of materials science and engineering. “But these αLA polymers have shown that they translate well across a range of applications and may be the start of a new industry paradigm, one built around multipurpose adhesives.”
After developing the surgical superglue, the researchers investigated its use in fetal surgery, in which an incision is made in the amniotic sac. The process can cause the sac to rupture, leak fluid or get infected, increasing the risk of pre-term delivery and fetal death. Typically, the incision is sealed by applying the adhesive at the conclusion, with limited success.
Using their surgical superglue, the researchers developed a new “presealing” approach that involves placing the αLA polymer adhesive on the tissue before puncturing with a needle — and is believed to be the first procedure of its kind in a preclinical study. The surgical superglue successfully sealed murine (mouse) amniotic sac ruptures, increasing fetal survival rate from 0% to 100%.
The researchers also created a pressure-sensitive adhesive and an epoxy-like structural adhesive, and they found that both surpassed the performance of conventional adhesives. These new adhesives are also environmentally friendly, in contrast to most on the market, which tend to be petroleum-based.
“These αLA polymer adhesives can be sustainably sourced — as αLA can be biomanufactured,” said researcher Subhajit Pal. “Also, they can be recycled in a closed loop system or left to degrade to non-toxic substances.”
Learn more: New recyclable adhesives can be easily adapted for medical, consumer and industrial applications; Recyclable surgical, consumer, and industrial adhesives of poly(α-lipoic acid) (Science)