Delivering drugs to the gut is not easy. Stomach acids dissolve drugs in some areas, hinder absorption in others, and can even alter the drug itself. On top of this, the gastrointestinal tract’s mucus lining prevents drugs from circulating for long periods of time.
A unique solution has now emerged, making use of “bio motors” built from algae. The Department of Nanoengineering and Chemical Engineering at the University of California San Diego (UCSD) has developed an “algal wagon” in pill form, overcoming the hurdles mentioned earlier.
The algae functions as a micromotor, allowing the platform to be maneuvered to where it can be most effective. Coated with cell membranes, they can be slipped past the immune system – so they can do their job effectively. Enclosing these in a pill protects them from stomach acids, and further simplifies the drug-delivery process.
“The algal motors’ ease of surface functionalization, inherent motility, and biocompatibility opens a plethora of possibilities for their usage in the diagnosis of GI tract-related diseases,” says Dr Amit Kumar Singh, Postdoctoral Research Fellow, George Mason University, Virginia, USA.
While micromotors have been used before, their efficacy was limited. They needed some form of fuel to function and could leave a non-biodegradable trail in the GI. Researchers now see the potential in using algae as replacements since they are natural swimmers – and biodegradable to boot.
Katerina Mostovaia, a Nanoengineer Scientist at Erba Mannheim, London says, “algae can perfectly deliver drugs for a long time. They have a stronger barrier and offer uniform distribution of the drug.”
The algae can even be customised to activate at different pH levels, allowing them to better access the diverse layers of the GI tract, notes Dr Singh.
Another bonus of using algae is that they have natural auto-fluorescent pigments. They glow – making it easier for doctors to track their progress through bioimaging. Moreover, they are relatively low cost. Algae are naturally occurring organisms that can be quickly cultivated in large quantities.
Algal motors have demonstrated encouraging outcomes in simulated GI fluids and mouse models during pre-clinical studies, but further research is needed to assess the practicality of algae motors as a drug delivery agent in a dysfunctional GI tract and for human trials. More study is also needed to follow the long-term impact of algal motors and understand the immunological response to them. While the long-term impact of these is yet to be seen, Dr Singh is confident that they could become one of the most promising cutting-edge drug delivery technologies in medical science soon.
Swimming algae drug delivery agents would not just be limited to the gut. Algal motors have already been used to deliver antibiotics to infected lung tissues.
Researchers at UCSD recently developed an antibiotic-laden algal motor to cure pulmonary pneumonia infection. The microrobots successfully eliminated pneumonia infection in mice during the pre-clinical studies. Furthermore, TransAlgae, an Israeli biotech company, has also produced genetically altered algae for oral administration of pharmaceutical drugs, paving the way for next-generation drug delivery systems.