Tag Archives: Bing Li

Cellulose-based wound sutures

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Caption: Advancing Surgical Sutures: The Promise of Cellulose-Based Materials. Credit: CAS Key Laboratory of Biobased Materials, Qingdao New Energy Shandong Laboratory, System Integration Engineering Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China

A January 22, 2025 Journal of Bioresources and Bioproducts news release on EurekAlert announces a review of cellulose-based (including nanocellulose) wound sutures,

A recent review published in the Journal of Bioresources and Bioproducts examines the state of cellulose-based sutures, focusing on materials, fabrication methods, and application performance. The study underscores the potential of these sutures as eco-friendly alternatives to traditional synthetic sutures, with significant advancements in biocompatibility and biodegradability.

Surgical sutures are critical in wound closure and healing, with traditional materials like cotton and synthetic polymers dominating the market. However, the rise of sustainable and biocompatible materials has led researchers to explore cellulose-based sutures as a viable alternative. A comprehensive review published in the Journal of Bioresources and Bioproducts provides an in-depth look at the current state of cellulose-based sutures, their fabrication methods, and potential applications.

Cellulose, the most abundant natural polymer on Earth, offers several advantages for surgical sutures, including non-toxicity, biocompatibility, and mechanical strength. The review covers various types of cellulose-based sutures, including natural cellulose, nanocellulose, and regenerated cellulose. Each type offers unique properties, with nanocellulose showing particular promise due to its high strength and flexibility. For instance, cellulose nanofibrils (CNF) have been used to create sutures with tensile strengths comparable to traditional materials, while maintaining excellent biocompatibility.

The review also highlights innovative fabrication methods such as wet spinning and interfacial polyelectrolyte complexation (IPC) spinning. Wet spinning is a traditional method used to create strong and flexible fibers, while IPC spinning allows for the creation of composite fibers with enhanced properties. These methods enable the production of sutures with tailored mechanical properties, biodegradability, and antibacterial characteristics.

One of the key challenges identified in the review is the need for consistent quality and improved biocompatibility in cellulose-based sutures. While natural cellulose fibers like cotton have been used historically, their quality can vary, leading to inconsistent performance. In contrast, nanocellulose and oxidized regenerated cellulose (ORC) offer more uniform properties and can be engineered for specific applications. For example, ORC sutures have demonstrated significant biodegradability, losing over 50% of their strength within 14 days, making them suitable for absorbable sutures.

The review also emphasizes the importance of multifunctional sutures that integrate antibacterial properties and growth factors to enhance wound healing. For instance, CNF/chitosan composite sutures have shown excellent antibacterial activity against common pathogens like Escherichia coli and Staphylococcus aureus, while maintaining high cell viability in vitro and in vivo.

Looking ahead, the review suggests that cellulose-based sutures could become the next generation of high-end medical sutures, driven by advancements in materials science and a growing focus on sustainability. Future research should focus on optimizing fabrication processes, enhancing mechanical properties, and conducting clinical trials to validate their performance.

Here’s a link to and a citation for the paper,

Cellulose-based suture: State of art, challenge, and future outlook by Meiyan Wu, Lei Ding, Xiaoying Bai, Yuxiang Cao, Mehdi Rahmaninia, Bing Li, Bin Li. Journal of Bioresources and Bioproducts Available online 15 December 2024 In Press, Corrected Proof DOI: https://doi.org/10.1016/j.jobab.2024.11.006

This paper is open access.

Not the same old gold: there’s a brand new phase

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A Dec. 7, 2015 news item on ScienceDaily announces a new phase for gold has been identified,

A new and stable phase of gold with different physical and optical properties from those of conventional gold has been synthesized by Agency for Science, Technology and Research (A*STAR) researchers [1], Singapore, and promises to be useful for a wide range of applications, including plasmonics and catalysis.

Many materials exist in a variety of crystal structures, known as phases or polymorphs. These different phases have the same chemical composition but different physical structures, which give rise to different properties. For example, two well-known polymorphs of carbon, graphite and diamond, arranged differently, have radically different physical properties, despite being the same element.

Gold has been used for many purposes throughout history, including jewelry, electronics and catalysis. Until now it has always been produced in one phase ― a face-centered cubic structure in which atoms are located at the corners and the center of each face of the constituent cubes.

Now, Lin Wu and colleagues at the Institute of the A*STAR Institute of High Performance Computing have modeled the optical and plasmonic properties of nanoscale ribbons of a new phase of gold — the 4H hexagonal phase (…) — produced and characterized by collaborators at other institutes in Singapore, China and the USA. The team synthesized nanoribbons of the new phase by simply heating the gold (III) chloride hydrate (HAuCl4) with a mixture of three organic solvents and then centrifuging and washing the product. This gave a high yield of about 60 per cent.

Here’s an image supplied by the researchers,

The atomic structure of the new phase of gold synthesized by A*STAR researchers. Reproduced from Ref. 1 and licensed under CC BY 4.0 © 2015 Z. Fan et al.

The atomic structure of the new phase of gold synthesized by A*STAR researchers. Reproduced from Ref. 1 and licensed under CC BY 4.0 © 2015 Z. Fan et al.

A Dec. 2, 2015 A*STAR news release, which originated the news item, provides more details,

The researchers also produced 4H hexagonal phases of the precious metals silver, platinum and palladium by growing them on top of the gold 4H hexagonal phase.

The cubic phase looks identical when viewed front on, from one side or from above. In contrast, the new 4H hexagonal phase lacks this cubic symmetry and hence varies more with direction — a property known as anisotropy. This lower symmetry gives it more directionally varying optical properties, which may make it useful for plasmonic applications. “Our finding is not only is of fundamental interest, but it also provides a new avenue for unconventional applications of plasmonic devices,” says Wu.

The team is keen to explore the potential of their new phase. “In the future, we hope to leverage the unconventional anisotropic properties of the new gold phase and design new devices with excellent performances not achievable with conventional face-centered-cubic gold,” says Wu. The synthesis method also gives rise to the potential for new strategies for controlling the crystalline phase of nanomaterials made from the noble metals.

Here’s a link to and a citation for the paper,

Stabilization of 4H hexagonal phase in gold nanoribbons by Zhanxi Fan, Michel Bosman, Xiao Huang, Ding Huang, Yi Yu, Khuong P. Ong, Yuriy A. Akimov, Lin Wu, Bing Li, Jumiati Wu, Ying Huang, Qing Liu, Ching Eng Png, Chee Lip Gan, Peidong Yang & Hua Zhang. Nature Communications 6, Article number: 7684 doi:10.1038/ncomms8684 Published 28 July 2015

This is an open access paper.

Micro-supercapacitor, leaves, and Korea’s Institute for Basic Sciences

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South Korea’s research on creating micro-supercapacitors (MSC) was first published online in February 2015 but it seems the researchers decided to promote the work after its print publication in May 2015.

A July 2, 2015 news item on Nanotechnology Now makes the announcement,

There was a time during the early development of portable electronics when the biggest hurdle to overcome was making the device small enough to be considered portable.  After the invention of the microprocessor in the early 1970s, miniature, portable electronics have become commonplace and ever since the next challenge has been finding an equally small and reliable power source.  Chemical batteries store a lot of energy but require a long period of time for that energy to charge and discharge plus have a limited lifespan.  Capacitors charge quickly but cannot store enough charge to work for long enough to be practical.  One possible solution is something called a solid-state micro-supercapacitor (MSC).  Supercapacitors are armed with the power of a battery and can also sustain that power for a prolonged period time.  Researchers have attempted to create MSCs in the past using various hybrids of metals and polymers but none were suitable for practical use.  In more recent trials using graphene and carbon nanotubes to make MSCs, the results were similarly lackluster.

An international team of researchers led by Young Hee Lee, including scientists from the Center for Integrated Nanostructure Physics at the Institute for Basic Science (IBS) and Department of Energy Science at Sungkyunkwan University in South Korea, has devised a new technique for creating an MSC that doesn’t have the shortcomings of previous attempts but instead delivers high electrochemical performance.

A June 29, 2015 South Korea Institute for Basic Science (IBS) press release by Daniel Kopperud, which originated the news item, reveals this research is bioinspired,

When designing something new and complex, sometimes the best inspiration is one already found in nature.  The team modeled their MSC film structure on natural vein-textured leaves in order to take advantage of the natural transport pathways which enable efficient ion diffusion parallel to the graphene planes found within them.

To create this final, efficient shape, the team layered a graphene-hybrid film with copper hydroxide nanowires.  After many alternating layers they achieved the desired thickness, and added an acid solution to dissolve the nanowires so that a thin film with nano-impressions was all that remained.

To fabricate the MSCs the film was applied to a plastic layer with thin, ~5μm long parallel gold strips placed on top.  Everything not covered by the gold strips was chemically etched away so that only the gold strips on top of a layer of film were left.  Gold contact pads perpendicular to the gold strips were added and a conductive gel filled in the remaining spaces and was allowed to solidify.  Once peeled from the plastic layer, the finished MSCs resemble clear tape with gold electrical leads on opposite sides.

The team produced stunning test results. In addition to its superior energy density, the film is highly flexible and actually increases capacitance after initial use.  The volumetric energy density was 10 times higher than currently available commercial supercapacitors and also far superior to any other recent research.  The MSCs are displaying electrical properties about five orders of magnitude higher than similar lithium batteries and are comparable to existing, larger supercapacitors.  According to Lee, “To our knowledge, the volumetric energy density and the maximum volumetric power density in our work are the highest values among all carbon-based solid-state MSCs reported to date.”

In the future, consumers will likely power their devices with MSCs instead of batteries.  Applications for light, reliable energy storage combined with a long lifespan and fast charge/discharge time.  The team’s MSCs could be embedded into an electronic circuit chip as power sources for practical applications such as implantable medical devices, active radio frequency identification tags, and micro robots.  If engineers utilize the material’s incredible flexibility, these MSCs could be utilized in portable, stretchable, and even wearable electronic devices.

Here’s a link to and a citation for the paper,

Leaf Vein-Inspired Nanochanneled Graphene Film for Highly Efficient Micro-Supercapacitors by Jian Chang, Subash Adhikari, Tae Hoon Lee, Bing Li, Fei Yao, Duy Tho Pham, Viet Thong Le, and Young Hee Lee. Advanced Energy Materials, Volume 5, Issue 9, May 6, 2015 First published online Feb. 20, 2015 DOI: 10.1002/aenm.201500003

This paper is behind a paywall.