We wanted to share with you some of the most popular articles published in Nanoscale Horizons from last year. These articles are some of the most highly cited, most read, or most highly shared articles published in 2018.

Our community have published some fantastic research in Nanoscale Horizons during 2018 and we wanted to make it even easier for you to find the best articles.

Nanoscale Horizons most popular articles, 2018

Here are just a few picks from the collection. We hope you enjoy them.

Reviews

Review on nanoscale Bi-based photocatalysts

Rongan He, Difa Xu, Bei Cheng, Jiaguo Yu and Wingkei Ho

Nanoscale Horiz., 2018, 3, 464-504

Group 6 transition metal dichalcogenide nanomaterials: synthesis, applications and future perspectives

Morasae Samadi, Navid Sarikhani, Mohammad Zirak, Hua Zhang, Hao-Li Zhang and Alireza Z. Moshfegh

Nanoscale Horiz., 2018, 3, 90-204

Communications

Nanoscale membrane architecture of healthy and pathological red blood cells

Andra C. Dumitru, Mégane A. Poncin, Louise Conrard, Yves F. Dufrêne, Donatienne Tyteca and David Alsteens

Nanoscale Horiz., 2018, 3, 293-304

MBene (MnB): a new type of 2D metallic ferromagnet with high Curie temperature

Zhou Jiang, Peng Wang, Xue Jiang and Jijun Zhao

Nanoscale Horiz., 2018, 3, 335-341

A tumor treatment strategy based on biodegradable BSA@ZIF-8 for simultaneously ablating tumors and inhibiting infection

Qiong Wu, Mei Li, Longfei Tan, Jie Yu, Zengzhen Chen, Liuhui Su, Xiangling Ren, Changhui Fu, Jun Ren, Laifeng Li, Feng Cao, Ping Liang, Yu Zhang and Xianwei Meng

Nanoscale Horiz., 2018, 3, 606-615

For more articles, see the full collection here.

Supramolecular polymers are promising architectures for different applications in the materials or biological fields between others. Their inherent dynamicity and versatility give to these materials interesting application-related properties but at the same time make their construction intricate. The control over these assembly processes of supramolecular polymers is still nowadays a big challenge to overcome. Therefore, there is a need of new methods that shed light in the understanding of the supramolecular driven assembly processes in different situations.

In a recent study reported in Nanoscale Horizons, Montenegro et al. conveniently employed water micro-droplets to investigate the assembly of tubular peptidic nanotubes in a confined space. They employed cyclic peptides decorated in one hand with histidine that confer the system a pH-responsive self-assembly and in the other hand with a pyrene moiety that serves as a fluorescent reported of the fibrillation process.

Figure 1. a) Structure and pH-dependent self-assembly of the cyclic peptide (CP1) b) Histidine hydrogen-bonded networks and pyrene  p-stacking driven aggregation of single peptide nanotubes by hierarchical micro-fibrillation. c) Supramolecular polymerization of CP1 in confined spaces [(i) CP1 in water (1–2% w/w); (ii) CP1 (1–2% w/w) in HEPES 30 mM at pH 8; (iii) addition of propanamine] shown in epifluorescence images and confocal microscopy projections of individual droplets. Scale bars from left to right are 20, 5 μm, and 10 μm. Images reproduced with permission of the Royal Society of Chemistry.

The observed deformation of the droplet upon basic pH trigger was produced by the strong directional self-assembly reflecting the strong directionality of the process. These findings with the one-dimension hierarchical assemblies open the possibility to a better comprehension of the physics and mechanism involved in the assembly of tubular networks in confined environments. Moreover, the reported system can already serve as a platform to further study such assembly processes in a biological scenario and eventually be applied for several biomedical purposes like drug delivery.

Article written by Dr. Julián Bergueiro Álvarez (Freie Universität Berlin). His current research is focused on thermoresponsive helical poylmers, polymer-gold nanoparticle supramolecular assemblies, and thermoresponsive nanogels as novel drug delivery nanocarriers. Find out more about his work on his website (http://www.nanominions.com/) and on Twitter (@nanominions).

With rapid advances in nanomedicine, non-toxic, biodegradable targeted nanocarriers that can encapsulate active drugs or biological molecules and can confer controllable release of its payloads at the target sites have emerged as novel theranostic tools for more sensitive and accurate diagnostics and more effective therapies. As such, by our evolving understanding of diseases and the impact of the current nanocarriers, moving towards the development of further enhanced and smart, stimuli responsive polymers is trivial. However, it is not without challenge to design such materials in a reproductive and controlled manner. Therefore, new synthesis methods and protocols that can lead to multi-component nanocarriers of optimal size and shape that are receptive to disease pathology and biochemistry and are fully non-toxic, biodegradable and allow a targeted distribution are highly timely.

Keti Piradashvili et al. recently reported in Nanoscale Horizons an effective and yet simple preparation of such nanocarriers that are stable in blood plasma and are enzymatically degradable. For their preparation, a light-triggered and catalyst-free tetrazole–ene cycloaddition (TET-click) on the bio-degradable natural polymers, human serum albumin (HSA) was achieved.  First, TET was attached to HSA by Steglich amidation; and second; an inter-facial cross-linking reaction of the TET-HSA in a water-in-oil mini-emulsion was used to obtain the stable fluorescent aqueous nanocarriers by irradiation of the mixture with UV light at 254 nm. (Fig.1).

Figure 1. Preparation of protein nanocarriers. (a) Non-fluorescent protein–TET conjugates were cross-linked by dinorbornene in inverse mini-emulsion to obtain self-fluorescent protein nanocarriers; (b) reaction mechanism of the bioorthogonal UV-light induced 1,3 dipolar tetrazole–ene cycloaddition; (c) experimental setup with a peristaltic pump pumping the emulsion through a quartz cuvette with the UV-lamp placed in front; (d) average size of various protein nanocarriers; (e) TEM image of the protein nanocarriers. Image reproduced with permission of the Royal Society of Chemistry.

The synthesized nanocarriers were shown to encapsulate a high drug payload (R848) of more than 90%. Besides, the encapsulated R848 nanocarriers were highly internalized into the derived dendritic cells (BMDCs) and released in a functional manner, as well as being extremely stable. There were no signs of aggregation or degradation, even after ca. 8 months of storage, so no leakage of the R848 occurred.

This approach could be utilized as a platform to design a variety of encapsulation on a vast range of proteins. Further preclinical and clinical testing is needed for the clinical translation of such nanotherapeutics. Nevertheless, the efficient methods reported here could play a pivotal roll along the evolutionary and revolutionary path of nanotherapeutics.

Dr. Orza is a member of the Community Board for Nanoscale Horizons. She is a Senior Research Scientist in the Laboratory of Nanomedicine at Emory Medical School, USA. She completed her Ph.D. on the development of therapeutic nanoparticles in the Department of Chemistry, Liverpool University, UK and Babes Bolyai University, Romania. Her research is focused on developing hybrid-engineered nanomaterials for biomedical applications, such as: tissue engineering and cancer treatment/diagnosis. Creative approaches to the design of such nanomaterials come from chemistry, biotechnology, biology/medicine, and engineering. Additionally, Dr. Orza is a Director and Chief Scientist at IndagoMed. LLC, USA, a company focused on creating performance products through the use of nanotechnology.

The sustainability issues of efficient energy storage and water purification are of vital importance to the long-term future of the planet. Researchers from Zhejiang University have developed a new nanostructured graphene material with a tuneable surface texture which can be used to for enhanced water purification and energy storage applications.

Inspired by the hierarchical structures and microscopic surface textures of the dry-climate plant Callitris endlicheri, the graphene structures use capillary effects to transport and store water in a similar way, but at much smaller length scales. Typically, tuneable surfaces such as these, require chemical surface modifications; but this Nanoscale Horizons article outlines a new method involving plasma-assisted growth of graphene ‘nano-flaps’ covalently bonded to micro-sized vertical grapheme graphene wells (termed ‘Sub-μGW’). The surfaces showed better water purification of metal nanoparticles from water and remarkable electrochemical performance in supercapacitors (2.5x higher specific capacitance of Sub-μGW electrodes). These excellent properties are attributed to enhanced solid-liquid interfacing leading to a super hydrophilic surface by reduction of air bubbles, and better device performance.

In the future, this biomimetic approach could be used to control the wettability of a range of porous microstructured surfaces, and could lead to further breakthroughs in important areas such as energy storage and conversion, water purification, and biomedical devices.

Fig. 1. SEM images of grapheme nanostructures showing the decreasing nanotexture densities from (d) to (f). (g) Schematic of the capillarity driven modification process for the adjustment of the nanotexture density in Sub-mGWs.

Read the article:
Tuneable fluidics within graphene nanogaps for water purification and energy storage
Zheng Bo, Yilei Tian, Zhao Jun Han, Shenghao Wu, Shuo Zhang, Jianhua Yan, Kefa Cena and Kostya Ostrikov
Nanoscale Horizons, 2017, Advance Article, DOI: 10.1039/C6NH00167J

Alexander Cook is a guest web writer for the RSC journal blogs. He is a PhD researcher in the Perrier group at the University of Warwick, focusing on polymer materials and their use in various applications. Follow him on twitter @alexcook222

Confocal images of a single cell under the magnetic micropen before and after turning on the external field

Single cell manipulation can provide insight into cell mechanics and adhesion, and has a crucial role in in vitro fertilization (IVF). Bartusz Grzybowski at Ulsan National Institute of Science and Technology in South Korea and his team’s new technique for this doesn’t need cells to be magnetically tagged beforehand. It also avoids the risks of heat- or stress-induced cell damage that can occur with other methods.

Grzybowski et al.’s method relies on an iron oxide nanoparticle medium in which cells are suspended. Applying an electromagnet to the magnetic medium through a micropen creates field gradients, which direct the cell to move in a certain direction. By varying how the micropen “tweezers” are positioned, cell movement can be manipulated in both 2 and 3 dimensions.

As well as controlling a single cell, the micropen can be used to pick up several cells together and guide them into regularly shaped clusters. Although it’s a long way off, this could one day be used to make IVF processes more efficient, reducing the number of potential embryos that need to be discarded. It could also be extended to manipulating bacteria and other single-celled organisms to conduct detailed studies on their behaviour.

Read the full article for free, here:
Trapping, manipulation and crystallization of live cells using magnetofluidic tweezers
J. V. I. Timonen, C. Raimondo, D. Pilans, P. P. Pillai and B. A. Grzybowski
Nanoscale Horiz., 2016, Advance Article

Susannah May is a guest web writer for the RSC Journal blogs. She currently works in the Publishing Department of the Royal Society of Chemistry, and has a keen interest in biology and biomedicine, and the frontiers of their intersection with chemistry. She can be found on Twitter using @SusannahCIMay.

Fig. 1 Schematic images of sculptured metal surfaces.

Surface properties are critically important for metal applications, especially when using alloys or composite. A key factor in these properties is the layers of metal oxide that develop on metal surfaces – how these layers form and dissolve has a huge impact on the surface stability. Conventional methods for creating metal surfaces often result in uneven oxide layers, weakening the properties.

Nanosculpturing, on the other hand, allows oxide deposition and dissolution to be controlled so that they can be evenly spread. This gives the surfaces the same properties across their whole area, making them very stable. Adelung’s group used a careful balancing act between direct and indirect dissolution, which gave them the benefits of both.

The nanoscale sculptured surfaces were also remarkably corrosion-resistant, and could be made hydrophobic or hydrophilic by alternately dehydrating or hydrating the oxide layer. With its property-boosting effects and wide scope, nanoscale sculpturing could soon be used for an array of metal applications.

Read the full article here:
Making metal surfaces strong, resistant, and multifunctional by nanoscale-sculpturing
M. Baytekin-Gerngross, M. D. Gerngross, J. Carstensen and R. Adelung
Nanoscale Horiz., 2016, Advance Article

Susannah May is a guest web writer for the RSC Journal blogs. She currently works in the Publishing Department of the Royal Society of Chemistry, and has a keen interest in biology and biomedicine, and the frontiers of their intersection with chemistry. She can be found on Twitter using @SusannahCIMay.

Time-gated luminescence image of injured mouse brains. Dashed white circles indicate region of penetrating brain injury. Targeted and nontargeted nanoparticles are compared. Inset: Bright field image (in gray scale) under ambient light.

A novel siRNA delivery system that could pave the way for genetic treatment of cancer, neurogenerative diseases or even HIV has been described in a new HOT article published in Nanoscale Horizons.

Over the last few years siRNA (small interfering RNA) has gained increasing attention as a new way to treat genetic diseases or viruses by silencing the genes responsible – the RNA fragments prevent the proteins that cause the illness from ever being expressed in the first place, making it the ultimate preventative therapy. However, current efforts have been hampered by the difficulty of delivering the delicate siRNA to the brain in one piece, before it’s degraded or attacked by the body’s immune defences.

This new system, developed by Michael Sailor’s team at the University of California, San Diego, uses porous silica nanoparticles as a protective carrier of the siRNA – the siRNA is hidden inside the pores of the nanoparticles where it’s protected from the body’s immune responses and harsh cell environments. A graphene oxide shell around the nanoparticles ensures that the siRNA stays safely inside them until they reach the brain. They will then release the still-intact siRNA,  where it prevents sections of DNA from producing damaging proteins.  The nanoparticles, which are fluorescent and easily tracked on their journey through the body, can be targeted to specific brain cells by attaching certain peptides; when the researchers attached rabies virus glycoprotein to the nanoparticles,  their uptake by neuronal cells doubled. The system successfully silenced genes in cell cultures – even in the presence of RNA-degrading nucleases – and, promisingly, proved capable of delivering siRNA to the brains of live mice who had suffered brain injuries. Significantly more of the siRNA-carrying nanoparticles accumulated around damaged tissues than the healthy brain tissues, and released large quantities of siRNA once they got there.

Although it’s early days, the system shows great promise for genetic therapies using siRNA. By using siRNAs to silence the genes responsible for out-of-control replication of cells, it could one day be used in the prevention of cancer – and siRNAs targeted to viral proteins could even be used to successfully treat HIV.

Read the full article here:

Porous silicon–graphene oxide core–shell nanoparticles for targeted delivery of siRNA to the injured brain
Jinmyoung Joo, Ester J. Kwon, Jinyoung Kang, Matthew Skalak, Emily J. Anglin, Aman P. Mann, Erkki Ruoslahti, Sangeeta N. Bhatia and Michael J. Sailor
Nanoscale Horiz., 2016, Advance Article, DOI: 10.1039/C6NH00082G

Susannah May is a guest web writer for the RSC Journal blogs. She currently works in the Publishing Department of the Royal Society of Chemistry, and has a keen interest in biology and biomedicine, and the frontiers of their intersection with chemistry. She can be found on Twitter using @SusannahCIMay.