The recent breakthrough in the field of Robotics, spearheaded by the Max Planck Institute for Intelligent Systems (MPI-IS) and Max Planck Institute for Solid State Research (MPI-FKF), Stuttgart, Germany, has revealed the potential to use light as a fuel source to assist microbots movement in real-body conditions. The primary function of these microbots or ‘microswimmers’ is to provide intelligent drug delivery specifically sensitive to cancer cells.
About Microswimmers
Microbots are composed of the two-dimensional compound poly (heptazine imide) carbon nitride commonly known as PHI carbon nitride. Their size ranges from 1-10 micrometre, which is minutely smaller than one-millionth of a metre. These bots have the capability to self-propel when energised by light, attributing their other name ‘microswimmers’.
Movement Mechanism of Microswimmers
PHI carbon nitride microparticles that make up these microbots are photocatalytic, meaning they react under light exposure. As light illuminates half of these nearly spherical particles, it triggers a light-driven process called photocatalysis only on the brightened hemisphere. The ions move from the bright side to the dark side, allowing micro-swimmers to aim towards the light source. This reaction paired with the particle’s electric field facilitates the swimming of these microbots.
Barriers to Microbot Movement
A challenge to microbot movement lies in the presence of dissolved salts in body fluids and blood. The natural reaction of these salts is to bind or recombine with movement ions, stopping them in their tracks. Consequently, this hinders chemically propelled swimmers from operating in salt solutions. For instance, when common salt (NaCl) is dissolved in water, it segregates into sodium (Na+) and chloride (Cl-) ions, which neutralise the ions created by the photocatalytic reaction, thus impeding self-propulsion.
The Research’s Contribution
The researchers discovered that the ions in the salty solution are capable of passing through the pores of PHI carbon nitride, minimising or eliminating resistance from the salt ions. Furthermore, the voids and pores on these microparticles serve as cargo bays that can absorb large amounts of drugs. Previous microswimmers intended for drug delivery relied on artificial capsules, which posed complexities and high costs in their creation. In contrast, the particles used in this research are cost-effective, organic, and sponge-like by design, directly binding to drugs or other substances, making them more practical for large-scale applications. Notably, they can carry more drugs amounting to 185% of their own mass, surpassing other materials previously used.
Significance of the discovery
Microswimmers bring a new perspective in medicinal drug application, potentially allowing targeted drug delivery within the human body. They can also assist in introducing specific substances into lakes or oceans. These swimmers could be used to aid endangered natural environments by treating specific animal species or exterminating harmful organisms.
Nanotechnology’s role in the health sector
Nanotechnology plays a significant role in the health sector, particularly in targeted drug delivery and gene therapy. It involves the study and application of structures sized between 1 nm ( nanometer) and 100 nm. Gene therapy, a method utilizing genes to treat or prevent diseases, illustrates the innovative use of nanotechnology in medicine. This approach allows doctors to introduce a gene into the patient’s cells, an effective alternative to drugs or surgery.