Researchers have developed self-propelled micromotors which employ a targeted gas therapy to treat rheumatoid arthritis. Subsequently, these micromotors successfully treated rheumatoid arthritis with a hydrogen-based gas therapy when injected into the joints of rats.
Rheumatoid arthritis is a chronic inflammatory-based disease linked to the excess production of a highly reactive molecule produced during the metabolism of oxygen, known as reactive oxygen species (ROS). Once produced, these ROS can then oxidize to cause painfully swollen joints, while degrading cartilage and bone and activating inflammatory cytokines.
Although medications, such as steroids and anti-inflammatory drugs can help slow joint destruction and relieve pain, they are known to have debilitating side effects whilst producing lackluster results. This means, more bio-friendly treatments demonstrating greater efficacy are needed.
Micromotors to treat arthritis in the joints
Now, a study from researchers led by Southern Medical University develops self-propelled micromotors that deliver a highly effective gas therapy to improve rheumatoid arthritis symptoms when injected into the joints of rats. The team states their micromotors show great potential in the treatment of rheumatoid arthritis. The study is published in the journal ACS’ Nano Letters.
Previous studies indicate a growing interest in the emerging field of gas therapies. In particular, this field has shown great promise in the treatment of inflammatory-based diseases such as arthritis and cancer. Namely, the novel field of gas therapies involves commonly occurring gases such as oxygen or hydrogen being used to treat disease. However, challenges remain regarding the concentration and controlled delivery of gas at the site of disease, compounded by the added risk of poisoning.
Specifically, hydrogen gas has been shown to neutralize ROS and decrease inflammatory cytokine levels when given to patients in drinking water. Unfortunately, the gas is poorly soluble in bodily fluids and quickly eliminated when given orally, limiting its therapeutic effects. Accordingly, the development of nanomedicines enabling the targeted and controlled release of hydrogen gas directly inside the affected arthritic joint is highly desired.
The current study develops a biocompatible micromotor that delivers hydrogen gas straight to the joint for precise rheumatoid arthritis management.
Microbots deliver & augment gas therapies
The present clinical trial engineers magnesium-based micromotors in the shape of tiny spheres. The spherical microbots exist on the micrometer scale at one-thousandth of a millimeter, measuring no more than the width of a human hair. They are housed within a magnesium outer shell that reacts with water to produce hydrogen bubbles. Furthermore, these bubbles not only act as a propellant but also provide a controlled-release gas therapy directly to the affected joints. In addition, the microbots are also coated with hyaluronic acid, a joint lubricant, to augment the hydrogen gas therapy.
Results show when the micromotors were trialed in a simulated joint environment they displayed prolonged, sustained release of hydrogen bubbles and could move on their own. To verify these data, the micromotors were then injected into the joints of rats serving as an animal model of rheumatoid arthritis. Data findings gained using ultrasound show the treated rats exhibited less-swollen paws, reduced bone erosion, and lower levels of inflammatory cytokines when compared with untreated rats.
How the gas therapy works on arthritis
The group states hydrogen bubbles generated when the magnesium-based microbots not only function as a propellant but also scavenge ROS and inflammation. They go on to explain that by scavenging ROS and inflammation using active hydrogen, the oxidative stress is relieved and the levels of inflammatory cytokines are reduced. Consequently, this raises therapeutic efficacy in ameliorating joint damage whilst suppressing the overall severity of arthritis in rats.
The team surmises they have engineered self-propelled microbots that can be precisely rendered to treat rheumatoid arthritis within the joint. For the future, the researchers state their micromotors show great promise in the treatment of rheumatoid arthritis and other inflammatory diseases.
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