Tag: hydrogel

A Novel Hydrogel for Treating Spinal Cord Injury

Photo by Kanasi on Unsplash

Researchers at the Chinese Academy of Sciences have developed an innovative scaffold that regulates the immune microenvironment following a spinal cord injury, thereby reduces secondary injury effects. Their work is reported in Biomaterials.

By modifying a hydrogel with a cationic polymer, polyamidoamine, and  interleukin-10 (IL-10; an anti-inflammatory cytokine), the scaffold could enhance tissue remodelling and promote axonal regeneration.

Spinal cord injuries cause axon damage and neural cell death, leading to dysfunction. A secondary stage of injury follows the primary stage and lasts for several weeks. Infiltration and activation of immune cells triggered by a spinal cord injury creates an inflammatory microenvironment characterised with damage-associated molecular patterns (DAMPs) that exacerbates secondary damage and impairs neurological functional recovery.

With the capabilities of effective scavenging of DAMPs and sustained release of IL-10, such a dual-functional immunoregulatory hydrogel not only reduced pro-inflammatory responses of macrophages and microglia, but also enhanced neurogenic differentiation of neural stem cells.

In a mouse model of spinal cord injury, the scaffold suppressed cytokine production, counteracting the inflammatory microenvironment and regulating immune cell activation, resulting in neural regeneration and axon growth without scar formation.

The dual-functional immunoregulatory scaffold with neuroprotection and neural regeneration effects significantly promoted electrophysiological enhancement and motor function recovery after spinal cord injury.

This study suggests that functional scaffold reconstruction of the immune microenvironment is a promising and effective method for treating severe spinal cord injury.  

Source: Chinese Academy of Sciences

An Oxygen-delivering Hydrogel for Diabetic Foot Ulcers

Photo by Denes Kozma on Unsplash

A quarter of people with diabetes develop foot ulcers, which are slow to heal due to hypoxic conditions in the wound from impaired blood vessels and increased inflammation. These wounds can become chronic, leading to poor quality of life and possibly amputation.

Jianjun Guan, professor of mechanical engineering and materials science at the McKelvey School of Engineering at Washington University in St. Louis, has developed a hydrogel that delivers oxygen to a wound and decreases inflammation, helps to remodel tissue and speeds up healing. The results are published in Science Advances

Prof Guan’s new hydrogel uses microspheres to gradually release oxygen to interact with the cells by means of an enzyme coating that converts the microsphere’s contents into oxygen. In this way, the hydrogel delivers oxygen over two weeks, reducing inflammation and promoting healing.
“The oxygen has two roles: one, to improve skin cell survival under the low-oxygen condition of the diabetic wound; and two, oxygen can stimulate the skin cells to produce growth factors necessary for wound repair,” Prof Guan said.

Source: Washington University in St. Louis

A 3D Printed Hydrogel With Self-healing Capacity

Much research has focused on hydrogels, polymer-based materials containing large amounts of water, but hydrogels with both self-healing and complex construction have proved elusive until now. 

Hydrogels need to fulfil two key criteria if they are to be effective replacements for organic tissue: the ability to form extremely complex shapes, and to self-heal after sustaining damage. Previously, hydrogels created in the laboratory had either the capability of being 3D printed into complex shapes, or had the ability to self-heal. This research realises the first time these two capabilities had been combined into one material.

The development of these materials may now be easier, and cheaper, thanks to the use of 3D printing: the researchers in the MP4MNT (Materials and Processing for Micro and Nanotechnologies) team of the Department of Applied Science and Technology of the Politecnico di Torino, coordinated by Professor Fabrizio Pirri. The researchers detailed their work in the prestigious journal Nature Communications.

In addition, the hydrogel was created using both commercially available materials and printer, thus making the approach proposed extremely flexible and potentially applicable anywhere, throwing open the door for development in the fields of both biomedicine and soft robotics.

The research was carried out in the context of the HYDROPRINT3D doctoral project, funded by the Compagnia di San Paolo, in the frame of “Joint Research Projects with Top Universities” initiative, by the PhD student Matteo Caprioli, under the supervision of the DISAT researcher Ignazio Roppolo, in collaboration with Professor Magdassi’s research group of the Hebrew University of Jerusalem (Israel).
The researchers used the digital pulsed light to create a semi-interpenetrated structure of polymer strands that, when severed, could rejoin in 12 hours at room temperature with no outside intervention. The restored section retains 72% of its initial strength.

“[For] many years, in the MP4MNT group, a research unit coordinated by Dr Annalisa Chiappone and I, specifically devoted to development of new materials that can be processed using 3D printing activated by light,” said Ignazio Roppolo, Researcher, DISAT. “3D printing is able to offer a synergistic effect between the design of the object and the intrinsic properties of materials, making [it] possible to obtain manufactured items with unique features.

“From our perspective, we need to take advantage of this synergy to best develop the capabilities of 3D printing, so that this can truly become an element of our everyday life. And this research falls right in line with this philosophy.”

This research represents a first step towards the development of highly complex devices, which can exploit both the complex geometries and the intrinsic self-healing properties in various application fields. Once biocompatibility studies have been refined, it will be possible to use these structures both for cellular mechanism research and for regenerative medicine applications.

Source: News-Medical.Net

Journal reference: Caprioli, M., et al. (2021) 3D-printed self-healing hydrogels via Digital Light Processing. Nature Communications. doi.org/10.1038/s41467-021-22802-z.

New Adhesive Hydrogel For Soft Tissue Repair

Scientists have developed an injectable gel that serves as a biodegradable adhesive for various kinds of soft tissue injury.

Soft tissue tears are a common injury, and it is difficult for surgeons to secure the tissue back together, since stitches often do more harm than good. According to Dominique Pioletti, the head of the Laboratory of Biomechanical Orthopedics at EPFL’s School of Engineering, such surgeries often don’t produce the best results because the tissue doesn’t properly heal. 

Tears in tissue such as cartilage and the cornea, often fail to heal properly, and tissue repair strategies may be suboptimal. For example, loose pieces of cartilage are often excised for symptomatic relief, but the remaining cartilage in articulating joints is placed under greater burden and generates faster.

A long-standing goal for researchers around the world has been the development of an adhesive for soft tissue that can withstand the natural stresses and strains within the human body. Now, Pioletti’s group has come up with a novel family of injectable biomaterials that can adhere to various forms of soft tissue. Their gel-based bioadhesives, can be used in a variety of injury-treatment applications.
Like other hydrogels, this one has a high water content, 85%, and also has two key advantages: It is injectable anywhere in the human body, and it has high intrinsic adhesion without additional surface treatment. “What makes our hydrogel different is that it changes consistency while providing high adhesion to soft tissues,” said Peyman Karami, a postdoc at Pioletti’s lab who has developed the gel during his PhD. “It’s injected in a liquid form, but then sets when a light source is applied, enabling it to adhere to surrounding tissue.”

The hydrogel has an innovative design that allows its mechanical and adhesive properties to be tailored, making it an extremely versatile soft tissue glue that can be used throughout the human body.

To obtain these versatile properties in their hydrogel, the scientists took the base polymer and modified it with the compounds that play an important role in tissue adhesion. The first is known as Dopa and is derived from mussels. “Dopa is what lets mussels attach firmly to any kind of surface—organic or otherwise,” said Pioletti. The second is an amino acid that our bodies make naturally.

“The advantage of our hydrogel compounds is that, unlike some medical adhesives, they don’t interfere with the body’s chemical reactions, meaning our hydrogel is fully biocompatible,” said Karami.

The new hydrogel also possesses unique energy-dissipation characteristics that improve its adhesive capability. Karami added: “We had to achieve an adhesion mechanism for injectable hydrogels, through the resulting synergy between interfacial chemistry and hydrogel mechanical properties. The hydrogel is capable of dissipating the mechanical energy produced when the hydrogel deforms, so that it protects the interactions at the interface between the hydrogel and surrounding tissue.”

A further advantage of this hydrogel is that it can release drugs or cells to encourage tissue repair, which is especially beneficial for cartilage and other tissues that don’t regenerate on their own.

“Our in vitro tests showed that the hydrogel binds to many different kinds of tissue, including cartilage, meniscus, heart, liver, lung, kidney and cornea,” said Pioletti. “We’ve made a sort of universal hydrogel.”

The scientists have received a grant to research possible orthopedic applications of the gel, and hope to be able to release their innovation onto the market within the next five years.

Source: Medical Xpress

Journal information: An intrinsically‐adhesive family of injectable and photo‐curable hydrogels with functional physicochemical performance for regenerative medicine, Macromolecular Rapid Communications, DOI :10.100 2/marc.202000660