Lifeboat Foundation

Editor’s note: This story is being highlighted in ASU Now’s year in review. Read more top stories from 2018 here.

In a major advancement in nanomedicine, Arizona State University scientists, in collaboration with researchers from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences, have successfully programmed nanorobots to shrink tumors by cutting off their blood supply.

“We have developed the first fully autonomous, DNA robotic system for a very precise drug design and targeted cancer therapy,” said Hao Yan, director of the ASU Biodesign Institute’s Center for Molecular Design and Biomimetics and the Milton Glick Professor in the School of Molecular Sciences.

Presynapses locally recycle synaptic vesicles to efficiently communicate information. During use and recycling, proteins on the surface of synaptic vesicles break down and become less efficient. In order to maintain efficient presynaptic function and accommodate protein breakdown, new proteins are regularly produced in the soma and trafficked to presynaptic locations where they replace older protein-carrying vesicles. Maintaining a balance of new proteins and older proteins is thus essential for presynaptic maintenance and plasticity. While protein production and turnover have been extensively studied, it is still unclear how older synaptic vesicles are trafficked back to the soma for recycling in order to maintain balance. In the present study, we use a combination of fluorescence microscopy, hippocampal cell cultures, and computational analyses to determine the mechanisms that mediate older synaptic vesicle trafficking back to the soma. We show that synaptic vesicles, which have recently undergone exocytosis, can differentially utilize either the microtubule or the actin cytoskeleton networks. We show that axonally trafficked vesicles traveling with higher speeds utilize the microtubule network and are less likely to be captured by presynapses, while slower vesicles utilize the actin network and are more likely to be captured by presynapses. We also show that retrograde-driven vesicles are less likely to be captured by a neighboring presynapse than anterograde-driven vesicles. We show that the loss of synaptic vesicle with bound molecular motor myosin V is the mechanism that differentiates whether vesicles will utilize the microtubule or actin networks. Finally, we present a theoretical framework of how our experimentally observed retrograde vesicle trafficking bias maintains the balance with previously observed rates of new vesicle trafficking from the soma.

Cytoskeleton-based trafficking mechanics have long been explored because of their essential role in neuronal function and maintenance (Westrum et al., 1983; Okada et al., 1995; Sorra et al., 2006; Perlson and Holzbaur, 2007; Tao-Cheng, 2007; Hirokawa et al., 2009; Staras and Branco, 2010; Tang et al., 2013; Wu et al., 2013; Maeder et al., 2014; Guedes-Dias et al., 2019; Gramlich et al., 2021; Watson et al., 2023). Protein trafficking via cytoskeleton transport is essential for synaptogenesis (Perlson and Holzbaur, 2007; Santos et al., 2009; Klassen et al., 2010; Wu et al., 2013; Guedes-Dias et al., 2019; Guedes-Dias and Holzbaur, 2019; Kurshan and Shen, 2019; Watson et al., 2023) and to replace older proteins with newer proteins for efficient function (Cohen et al., 2013; Dörrbaum et al., 2018, 2020; Heo et al., 2018; Truckenbrodt et al., 2018; Jähne et al., 2021; Watson et al., 2023).

Down syndrome (DS) is one of the most prevalent genetic disorders in humans. The use of new approaches in genetic engineering and nanotechnology methods in combination with natural cellular phenomenon can modify the disease in affected people. We consider two CRISPR/Cas9 systems to cut a specific region from short arm of the chromosome 21 (Chr21) and replace it with a novel designed DNA construct, containing the essential genes in chromatin remodeling for inactivating of an extra Chr21. This requires mimicking of the natural cellular pattern for inactivation of the extra X chromosome in females. By means of controlled dosage of an appropriate Nano-carrier (a surface engineered Poly D, L-lactide-co-glycolide (PLGA) for integrating the relevant construct in Trisomy21 brain cell culture media and then in DS mouse model, we would be able to evaluate the modification and the reduction of the active extra Chr21 and in turn reduce substantial adverse effects of the disease, like intellectual disabilities. The hypothesis and study seek new insights in Down syndrome modification.

Keywords: Down syndrome, CRISPR/Cas9, Designed DNA construct, Poly D L-lactide-co-glycolide (PLGA), Nano-carrier, Chromosome 21 inactivation.

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Adopting electrostatic assembly processes where the nanoparticles attach themselves to an oppositely charged surface is a possible way out of this dilemma. Once a monolayer is formed, the nanoparticles self-limit further assembly by repelling other similarly charged nanoparticles away from the surface. Unfortunately, this process can be very time-consuming.

While artificial methods struggle with these drawbacks, underwater adhesion processes found in nature have evolved into unique strategies to overcome this problem. In this regard, a team of researchers from Gwangju Institute of Science and Technology, led by Ph.D. student Doeun Kim (first author) and Assistant Professor Hyeon-Ho Jeong (corresponding author), developed a “mussel-inspired” one-shot nanoparticle assembly technique that transports materials from water in microscopic volumes to 2-in. wafers in 10 seconds, while enabling 2D mono-layered assembly with excellent surface coverage of around 40%. Their work was published in Advanced Materials on April 18, 2024, and highlighted as a frontispiece.

“Our key approach to overcome the existing challenge came from observing how mussels reach the target surface against water. We saw that mussels simultaneously radiate amino acids to dissociate water molecules on the surface, enabling swift attachment of the chemical adhesive on the target surface. We realized that an analogous situation where we introduce excess protons to remove hydroxyl groups from the target surface, thus increasing the electrostatic attraction force between the nanoparticles and the surface and accelerating the assembly process,” said Ms. Kim when asked about the motivation behind the unique nature-inspired approach.

Unlock the potential of nanotechnology. Explore breakthroughs and challenges in energy, biomedicine, and more in our executive summary.

Carbon nanotubes (CNTs) are nanometer-scale structures with immense potential to improve different materials, but inconsistencies in their chemical and electrical properties, purity, cost, and concerns over possible toxicity present ongoing challenges. CNTs are a one-dimensional carbon allotrope made of an sp2 hybridized carbon lattice in a cylindrical shape. Single-walled CNTs are a simple tube, while multi-walled CNTs are nested concentrically or wrapped like a scroll (Figure 1).

These nanoscale materials feature a high Young’s modulus and tensile strength and can have either metallic or semiconducting electrical properties. Controlling their atomic arrangement (chirality) affects their conductivity, and because of this, researchers have been trying to understand how synthesis parameters can be used to generate CNTs with predictable electrical properties. The development of various chemical vapor deposition (CVD)-based recipes within the last 20 years to synthesize CNTs has improved this situation.

As we’ve seen in our analysis of the CAS Content Collection™, the world’s largest human-curated collection of published scientific information, the increase in patent activity indicates a high amount of interest in commercial applications for CNTs (Figure 2).

Discover the emerging landscape of single walled carbon nanotubes, the new applications and approaches across industries, and what future opportunities they offer.

Tumors that move to the brain are difficult to treat because of the brain-blood barrier that separates the brain from the rest of the body.

Sylvester Comprehensive Cancer Center researchers have developed a nanoparticle that could one day be used to treat brain metastases.

Carbon nanotubes are one of the most elastically strong materials out there.

When I was a kid, I used to take allowance money and occasionally buy rubber-band-powered balsa wood airplanes at a local store. Maybe you’ve seen these. You wind up the rubber band, which stretches the elastomer and stores energy in the elastic strain of the polymer, as in Hooke’s Law (though I suspect the rubber band goes well beyond the linear regime when it’s really wound up, because of the higher order twisting that happens). Rhett Alain wrote about how well you can store energy like this. It turns out that the stored energy per mass of the rubber band can get pretty substantial.

Carbon nanotubes are one of the most elastically strong materials out there. A bit over a decade ago, a group at Michigan State did a serious theoretical analysis of how much energy you could store in a twisted yarn made from single-walled carbon nanotubes. They found that the specific energy storage could get as large as several MJ/kg, as much as four times what you get with lithium ion batteries!

Continue reading “Wind-up nanotechnology” »