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Study shows that similarly charged particles can sometimes attract, rather than repel

‘Opposites charges attract; like charges repel’ is a fundamental principle of basic physics. But a new study from Oxford University, published in Nature Nanotechnology (“A charge-dependent long-ranged force drives tailored assembly of matter in solution”), has demonstrated that similarly charged particles in solution can, in fact, attract each other over long distances. Just as surprisingly, the team found that the effect is different for positively and negatively charged particles, depending on the solvent.

The study found that negatively charged silica microparticles suspended in water attracted each other to form hexagonally arranged clusters. (Image: Zhang Kang)

Besides overturning long-held beliefs, these results have immediate implications for a range of processes that involve interparticle and intermolecular interactions across various length-scales, including self-assembly, crystallisation, and phase separation.

Researchers demonstrate 3D nanoscale optical disk memory with petabit capacity

The most popular words of 2023 were recently released, with AI Large Language Model (LLM) unquestionably topping the list. As a front-runner, ChatGPT also emerged as one of the international buzzwords of the year. These disruptive innovations in AI owe much to big data, which has played a pivotal role. Yet, AI has simultaneously presented new opportunities and challenges to the development of big data.

High-capacity data storage is indispensable in today’s digital economy. However, major storage devices like and semiconductor flash devices face limitations in terms of cost-effectiveness, durability, and longevity.

Optical data storage offers a promising green solution for cost-effective and long-term data storage. Nonetheless, optical data storage encounters a fundamental limitation in the spacing of adjacent recorded features, owing to the optical diffraction limit. This physical constraint not only impedes the further development of direct laser writing machines but also affects and storage technology.

Scientists create dancing nanoparticles to explore quantum limitations

Enhancing quantum features compensates for environmental losses, amplifying particle interactions, achieving entanglement at higher scales.

One of the oldest topics of contemporary science is where to draw the line between classical and quantum physics.


Abstract

The ability to engineer cavity-mediated interactions has emerged as a powerful tool for the generation of non-local correlations and the investigation of non-equilibrium phenomena in many-body systems. Levitated optomechanical systems have recently entered the multi-particle regime, with promise for using arrays of massive strongly coupled oscillators for exploring complex interacting systems and sensing. Here, by combining advances in multi-particle optical levitation and cavity-based quantum control, we demonstrate, for the first time, programmable cavity-mediated interactions between nanoparticles in a vacuum. The interaction is mediated by photons scattered by spatially separated particles in a cavity, resulting in strong coupling (Gzz/Ωz = 0.238 ± 0.005) that does not decay with distance within the cavity mode volume. We investigate the scaling of the interaction strength with cavity detuning and inter-particle separation and demonstrate the tunability of interactions between different mechanical modes. Our work paves the way towards exploring many-body effects in nanoparticle arrays with programmable cavity-mediated interactions, generating entanglement of motion, and using interacting particle arrays for optomechanical sensing.

Fabrication of mechanochromic gallium nanostructures by capillary interactions

A process that leverages capillary interactions between oligomers in an elastomeric polydimethylsiloxane substrate and deposited Ga enables the formation of Ga nanodroplets with nanoscale gaps in a single step. Gap-plasmon resonances excited within the nanogaps give rise to structural colours that can be tuned by changing the oligomer content in the substrate or by mechanical stretching.

In vivo biomolecule corona and the transformation of a foe into an ally for nanomedicine

Nanoparticles (NPs) administered in the human body will undergo rapid surface modification upon contact with biological fluids driven by their interfacial interaction with a diverse range of biomolecules. Such spontaneous self-assembly and adsorption of proteins and other biomolecules onto the NP surface constitute what is commonly known as the protein or biomolecule corona. This surface biotransformation of the NPs modulates their biological interactions and impact on physiological systems and can influence their overall pharmacological profile. Here, we comment on how the initially considered ‘nuisance’ of the in vivo corona formation can now be considered a nanoparticle engineering tool for biomedical use, such as in endogenous tissue targeting, personalized biomarker discovery and immunomodulation.

Scientists make nanoparticles dance to unravel quantum limits

The question of where the boundary between classical and quantum physics lies is one of the longest-standing pursuits of modern scientific research, and in new research published today, scientists demonstrate a novel platform that could help us find an answer.

The laws of quantum physics govern the behavior of particles at miniscule scales, leading to phenomena such as , where the properties of entangled particles become inextricably linked in ways that cannot be explained by classical physics.

Research in quantum physics helps us to fill gaps in our knowledge of physics and can give us a more complete picture of reality, but the tiny scales at which operate can make them difficult to observe and study.

AI could find out when cancer cells will resist chemotherapy

In a new study, scientists have been able to leverage a machine learning algorithm to tackle one of the biggest challenges facing cancer researchers — predicting when cancer will resist chemotherapy.


But in what could be a game-changer, scientists at the University of California San Diego School of Medicine revealed today in a study that a high-tech machine learning tool might just figure out when cancer is going to give the cold shoulder to chemotherapy.

Teaming up against cancer

When cells divide, even the cancer ones, they rely on complex molecular machinery that helps them copy their DNA. Chemotherapy drugs usually put a stop to this DNA-copying mechanism, especially in fast-growing tumor cells.

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