A team of researchers at Oregon State University has created a new type of hyperthermic magnetic nanoparticle that can facilitate targeted cancer therapy. These new particles, known as core-shell particles, promise important advancements in providing access to tumours located deep in the body, allowing clinicians to heal tumours more effectively.
Traditional solutions aimed at destroying cancer cells, like chemotherapy and radiotherapy, have been faced with the problem of leaving neighbouring healthy tissue unscathed. It’s even more difficult with tumours lying in deep-seated organs and tissues, where invasive techniques have traditionally been used to access and eliminate such tumours. Previous generations of hyperthermic nanoparticles have not been particularly successful in destroying deeper tumours, as the necessary heating intensity requires a large dose of nanoparticles to be injected directly into the tissue. The new particles developed can reach temperatures up to 50 degrees Celsius, enhancing the heating potential of the magnets.
Made of a core and outer shell devised from different materials, the new nanoparticles are called core-shell particles. They have a core made of magnetite (ferrous ferric oxide, or Fe3O4) and a maghemite (γ-Fe2O3) shell. Formed by a thermal decomposition reaction, the new nanoparticles have an increased shell thickness, corresponding to ultrahigh heating capacity in an alternating magnetic field (AMF). The researchers note in a paper published in Small Methods that the core-shell particle exhibits a high heating efficiency, making it suitable for relatively inaccessible tumours.
Previous iterations of nanoparticles used for heating cancers have been known to only heat up to 44 degrees Celsius. While this is effective enough for killing cancers in situations where the researcher can inject the particles directly into affected tissue, it presents problems when the nanoparticles are used for less accessible tumours. With such tumours, the nanoparticles must travel through venous routes to reach their target tissues. With the increased heating potential of the core-shell nanoparticles, systemic delivery of nanoparticles – injecting them into the bloodstream – is more feasible. Researchers have already demonstrated that nanoparticles are effective for relatively accessible tumours, so the new particles would be a step further for nanoparticle therapy.
Applications for the New Nanoparticles in Cancer Management
The new core-shell nanoparticles developed by researchers at Oregon State University represent another stage in the development of minimally-invasive anticancer therapies. With the ability to destroy cancer cells with increasing specificity and intensity, nanoparticles will potentially advance cancer therapy. While clinical trials have yet to be explored in the new field of hyperthermic nanoparticle therapy, they’re set to be carried out soon, allowing clinicians to perform cancer management more effectively.
In 2015, researchers at the Institute of Atomic and Molecular Sciences at the Academia Sinica in Taiwan created the first biosafe gold nanoparticles that could provide localized heat when excited by an external energy source. Fluorescent nanodiamonds (FNDs) were used as thermometers in these particles, enabling the researchers to monitor how the nanoparticles heated up in the presence of an external energy source. Inherently biocompatible and non-toxic, fluorescent nanodiamonds conjugated with gold nanoparticles promise an efficient nanoheater for multiple applications. With up to a 10 K (10 degrees Celsius) rise in temperature possible with this technology, FNDs combined with gold nanoparticles were determined to be an effective tool for localized hyperthermia treatment.
One of the issues that the fluorescent nanodiamonds solved was the control of heat generation. Nanoparticles can be a great way to provide heat at a subcellular level. Still, predicting the amount or distribution of the heat generated can be difficult. If nanoparticles are thermally active in healthy tissue, they could lead to impairments in cell function and severe injuries to the patient. The Academia Sinica researchers provided an elegant solution to this issue, by implanting diamond nanocrystal thermometers into the gold nanorods. In response to an increase in temperature, these fluorescent nanodiamonds glow, allowing scientists to monitor the area receiving heating from the energized nanoparticles.
It wasn’t long before molecular biologists caught the significance of this discovery. As ecancer.org, a leading website for scientists and researchers in cancer, noted, “Precise targeting biological molecules, such as cancer cells, is a challenge due to their sheer size.” In an article commenting on the biocompatibility of the gold-diamond nanotechnology combo, eCancer.org postulated that “Gold nanoparticles can act as switchable nanoheaters for therapies based on delivering intense and precise heat to cancerous cells, using a laser as the energy source.”
Increased temperatures can permanently alter the molecular structures of cellular macromolecules in a process known as denaturation. Biomolecules such as proteins and DNA mediate cellular function and behaviour, and a change in their structures can result in losing their function. Factors such as heat and altered pH can change the structures of these biomolecules, leading to the alteration of functions and homeostasis. Cancer cells grow and proliferate without end, leading to the impairment of the normal function of neighbouring cells. With cancer cells, the targeted application of heat can halt cellular processes mechanisms such as denaturation, effectively taking them out of the bodily equation.
In the years since nanoparticles were developed, researchers have done pioneering work to make nanoparticle therapy safe and practicable for cancer management. For example, in 2018, a team of researchers at the University at Buffalo developed a zinc ferrite nanoparticle that could target tumours. As Hao Zeng, the team leader, beamed, “The treatment will only heat up the region where the nanoparticles are without affecting healthy tissues that are further away.”
A team at the University of London also showed that nanoparticles offer use in other anticancer mechanisms besides heat treatment. MedGadget reported that the nanoparticles could carry chemotherapy drugs to tumours in the body, limiting exposure to healthy tissues. With a polymer coating preventing the particles from releasing their drug payload until internalized in cancer cell lysosomes, targeted destruction of cancer cells through a two-pronged approach may be achievable. With the “potential to reduce the side effects of therapy” with synergistic efficacy, nanoparticles offer excellent promise for new therapies for managing cancers.
That’s a wrap on 2022, and what a terrific year it has been! We at SiGMA Group are incredibly grateful to all the delegates, collaborators, sponsors and of course, the core team itself whose hard work and support is crucial to hosting the landmark quality events everyone has come to associate with the name SiGMA.
That being said, the world keeps on turning, and so shall the wheels of this event-hosting machine that was kickstarted in 2014. Coming right up is SiGMA Group’s premier event in Africa, with Nairobi 2023 set for next January. Visit our webpage for more information!