Thanks to tiny microneedles, eye doctors may soon have a better way to treat diseases such as macular degeneration that affect tissues in the back of the eye. That could be important as the population ages and develops more eye-related illnesses
Excitement around the potential for targeted nanoparticles (NPs) that can be controlled by stimulus outside of the body for cancer therapy has been growing over the past few years. More specifically, there has been considerable attention around near-infrared (NIR) light as an ideal method to stimulate nanoparticles from outside the body. NIR is minimally absorbed by skin and tissue, has the ability to penetrate deep tissue in a non-invasive way and the energy from NIR light can be converted to heat by gold nanomaterials for effective thermal ablation of diseased tissue.
In new research from Brigham and Women’s Hospital (BWH), researchers describe the design and effectiveness of a first-of-its-kind, self assembled, multi-functional, NIR responsive gold nanorods that can deliver a chemotherapy drug specifically targeted to cancer cells and selectively release the drug in response to an external beam of light while creating heat for synergistic thermo-chemo mediated anti-tumour efficacy.
‘The design of this gold nanorod and its self-assembly was inspired by nature and the ability of complimentary strands of DNA to hybridize on their own without imposing complicated chemical processes on them,’ explained Omid Farokhzad, MD, an anesthesiologist, director of the Laboratory of Nanomedicine and Biomaterials at BWH, and senior author of this study. ‘Each functionalized DNA strand individually, and the self assembled components as a system, play a distinct yet integrative role resulting in synergistic targeted and triggered thermo-chemotherapy capable of eradicating tumours in our pre-clinical models.’
One DNA strand is attached to the gold nanorod and the complementary strand is attached to a stealth layer and a homing molecule that keeps the system under the radar of the immune system while targeting it directly to cancer cells. When the DNA strands come together, the targeted gold nanorod is formed and the double stranded DNA serves as the scaffold for binding the chemotherapy drug, doxorubicin, which can be released in response to NIR light that concurrently results in generation of heat by the gold nanorods.
‘This new platform is comprised of three distinct functional components and each plays a role in contributing to the triple punch of triggered thermotherapy, controlled doxorubicin release, and cancer cell targeting,’ explained Zeyu Xiao, PhD, a postdoctoral fellow at BWH and lead author of this study.
To demonstrate the robust capability of this nanorod system, Farokhzad and colleagues used a pre-clinical model to evaluate the in vivo anti-tumour efficacy in two different tumour models and four different groups with different drug regiments, each group varying in weight and tumour size. Researchers administrated an injection of the novel, self-assembled nanoparticle and then 10 minutes post-injection, the tumours were irradiated using NIR light that activated the nanoparticle using the gold nanorod and created heat. The results showed that this platform successfully delivered heat and anti-cancer drugs and synergistically eradicated tumors.
‘Thermal ablation is already commonly used in cancer treatment,’ said Dr. Farokhzad. ‘What is extremely exciting about this platform is that we are able to selectively target cancer cells and then hit the tumour twice: first with a controlled release of a chemotherapy drug and then secondly with triggered induction of heat from the activation of the gold nanorod. And all this can be done non-invasively.’
Brigham and Women’s Hospital
A new study suggests that nicotinamide, more commonly known as vitamin B3, may be able to combat some of the antibiotic-resistance staph infections that are increasingly common around the world, have killed thousands and can pose a significant threat to public health.
The research found that high doses of this vitamin increased by 1,000 times the ability of immune cells to kill staph bacteria. The work was done both in laboratory animals and with human blood.
The findings were by researchers from Cedars-Sinai Medical Center, the Linus Pauling Institute at Oregon State University, UCLA, and other institutions.
The work may offer a new avenue of attack against the growing number of ‘superbugs.’
‘This is potentially very significant, although we still need to do human studies,’ said Adrian Gombart, an associate professor in OSU
From the air, the twists and turns of rivers can easily be seen. In the body, however, tracing the twists and turns of blood vessels is difficult, but important. Vessel ‘bendiness’ can indicate the presence and progression of cancer.
This principle led UNC scientists to a new method of using a high-resolution ultrasound to identify early tumours in pre-clinical studies. The method, based on vessel bendiness or ‘tortuosity,’ potentially offers an inexpensive, non-invasive and fast method to detect cancer that could someday help doctors identify cancers when tumours are less than a centimetre in size.
Paul Dayton, PhD, associate professor of biomedical engineering explains, ‘The correlation between vessel tortuosity and cancer is well-established. What’s new about our finding is that we can visualise these vessels in minutes with a very quick scan, using very inexpensive imaging methods.’ Dr. Dayton is a member of UNC Lineberger Comprehensive Cancer Center.
The UNC team used a new high-resolution ultrasound method, called ‘acoustic angiography,’ with an intravascular contrast agent that allowed them to acquire images of only the blood vessels. ‘Unlike current clinical ‘grayscale’ ultrasound, this method filters out all tissue signals, so we can see small blood vessels clearly.’ says Dayton.
‘Our results showed a definitive difference between vessels within and surrounding tumours versus those associated with normal healthy vasculature. The limitation that we must now address is that our method works only for tumours at a shallow depth into tissue, such as melanomas or thyroid cancer. Our next studies will focus on this imaging-depth issue as well as evaluating the ability of this technology to determine a tumour
Surgeons at Boston Children’s Hospital have successfully implanted a modified version of a expandable prosthetic heart valve in several children with mitral valve disease. Unlike traditional prosthetic valves that have a fixed diameter, the expandable valve can be enlarged as a child grows, thus potentially avoiding the repeat valve replacement surgeries that are commonly required in a growing child. The new paradigm of expandable mitral valve replacement has potential to revolutionise care for infants and children with complex mitral valve disease.
The surgical team, led by Sitaram M. Emani, MD, and Pedro J. del Nido, MD, of the Department of Cardiac Surgery at Boston Children’s, have summarised their outcomes with two patients.
The care of patients with disease of the mitral valve
The Mount Sinai Medical Center is the first institution in New York State to use in the clinical setting a newly approved imaging technique to detect Alzheimer’s disease (AD) in people who are cognitively impaired. Until now, physicians have been limited in their ability to diagnose AD, guided almost exclusively by a patient’s mental and behavioural symptoms and family history. The innovative technique
A new three-dimensional (3-D) digital mammography technique has the potential to significantly improve the accuracy of breast cancer screening, according to a study.
Two-dimensional (2-D) x-ray mammography, the current primary screening method for early detection of breast cancer in women, is a valuable tool but has some limitations. Surrounding normal tissue can mask lesions, and 2-D views do not provide direct information about the volumetric appearance
Robotic surgery though the mouth is a safe and effective way to remove tumours of the throat and voice box, according to a study by head and neck cancer surgeons at the Ohio State University Comprehensive Cancer Center
Stroboscopic training, performing a physical activity while using eyewear that simulates a strobe-like experience, has been found to increase visual short-term memory retention, and the effects last for 24 hours.
Participants in a Duke University study engaged in physical activities, such as playing catch, while using either specialised eyewear that limits vision to only brief snapshots or while using eyewear with clear lenses that provides uninterrupted vision. Participants from the Duke community, including varsity athletes, completed a computer-based visual memory test before and after the physical activities. The study found that participants who trained with the strobe eyewear gained a boost in visual memory abilities.
Participants completed a memory test that required them to note the identity of eight letters of the alphabet that were briefly displayed on a computer screen. After a variable delay, participants were asked to recall one of the eight letters. On easy-level trials, the recall prompt came immediately after the letters disappeared, but on more difficult trials, the prompt came as late as 2.5 seconds following the display. Because participants did not know which letter they would be asked to recall, they had to retain all of the items in memory.
‘Humans have a memory buffer in their brain that keeps information alive for a certain short-lived period,’ said Greg Appelbaum, assistant professor of psychiatry at Duke and first author of the study. ‘Wearing the strobe eyewear during the physical training seemed to boost the ability to retain information in this buffer.’
The strobe eyewear disrupts vision by only allowing the user to see glimpses of the world. Users must adjust their visual processing in order to perform normally, and this adjustment produces a lingering benefit: once participants removed the strobe eyewear, there was an observed boost in their visual memory retention that was found to still be active 24 hours later.
Earlier work by Appelbaum and the project’s senior researcher, Stephen Mitroff, had shown that stroboscopic training improves visual perception, including the ability to detect subtle motion cues and the processing of briefly presented visual information. Yet the earlier study had not determined how long the benefits might last.
‘Our earlier work on stroboscopic training showed that it can improve perceptual abilities, but we dont know exactly how,’ said Mitroff, associate professor of psychology and neuroscience and member of the Duke Institute for Brain Sciences. ‘This project takes a big step by showing that these improved perceptual abilities are driven, at least in part, by improvements in visual memory.’
‘Improving human cognition is an important goal with so many benefits,’ said Appelbaum, also a member of the Duke Institute for Brain Sciences. ‘Interestingly, our findings demonstrate one way in which visual experience has the capacity to improve cognition.’
Duke University
April 2024
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