(Re)generation next: Novel strategy to develop scaffolds for joint tissue regeneration

March 30, 2020

Joint diseases, such as knee osteoarthritis, are common in the elderly population and severely impair their quality of life. Conventional treatments like artificial joint replacements offer temporary relief but come with several disadvantages, including limited functionality and the need for replacement. A better solution is to find a way to promote tissue regeneration in joints: interpenetrating polymer network (IPN) hydrogels, when injected into joints, do exactly this--by acting as scaffolds for the growth of new cells and mimicking the cellular environment. However, existing techniques to develop IPNs are tedious: they require the addition of chemicals via multiple steps, which limits their practical application. Thus, there is a need for better techniques that can make the process of tissue regeneration easier.

In a new study published in Chemistry of Materials, scientists from Japan, including Asst Prof Shigehito Osawa and Prof Hidenori Otsuka of Tokyo University of Science, found a new method for developing tissue regeneration scaffolds. Prof Otsuka explains, "Generally, the formation of IPN gels is a cytotoxic, multistep process: it involves constructing a network, followed by the addition of chemical reagents or subjecting them to external stimuli, such as temperature or changes in light irradiation, to form the other network. We wanted to create a novel scaffold using a one-step process, which could overcome the limitations of existing IPNs."

To begin with, the scientists wanted to find self-assembling compounds that could form independent 3D networks without interfering with each other. They began by selecting a peptide called RADA16, which--under physiological conditions--forms a network owing to electrostatic and hydrophobic interactions. Then, they turned to a biopolymer called chitosan (CH) and a compound called polyethylene glycol (PEG), which form networks with each other via chemical reactions. Because the mechanisms of network formation in RADA16 and CH/PEG were drastically different, the scientists speculated that these networks would not interfere with each other. By simply mixing the two compounds, they found that this was indeed true. Prof Otsuka explains, "We mixed the two materials, RADA16 and CH/PEG, and found that they successfully formed heterologous IPNs. Moreover, these IPNs did not interfere with each other, as it turns out that the RADA16 networks form first, followed by the slower assembly of CH/PEG networks."

Next, the researchers wanted to check if the proposed IPN could effectively act as a scaffold to promote the growth of healthy chondrocytes (cells that produce cartilage). The scientists tested the scaffold using human cells and found that cells are embedded uniformly in the hydrogel, effectively generating functional cartilage tissue. In fact, in mice, implanting human chondrocytes within the hydrogel scaffold led to cartilage formation over a period of 8 weeks, even surpassing the performance of conventional tissue scaffolds! The biggest advantage of this technique was that not only did it successfully regenerate cartilage tissue, it was also performed in just one step or "pot," making it much simpler than existing techniques.

These findings could potentially overcome the limitations of tissue regeneration and pave the way for further applications such as drug delivery, diagnosis, and surface modification. Not just this, Prof Otsuka is optimistic that owing to the ease of the technique, it can be produced domestically, which could lead to significant social and economic benefits. Prof Otsuka concludes, "Our research has opened doors to the use of regenerative medicine for autonomous cartilage generation as an alternative to artificial joints, leading to significant improvement in patients' quality of life and benefiting the society overall."
About The Tokyo University of Science

Tokyo University of Science (TUS) is a well-known and respected university, and the largest science-specialized private research university in Japan, with four campuses in central Tokyo and its suburbs and in Hokkaido. Established in 1881, the university has continually contributed to Japan's development in science through inculcating the love for science in researchers, technicians, and educators.

With a mission of "Creating science and technology for the harmonious development of nature, human beings, and society", TUS has undertaken a wide range of research from basic to applied science. TUS has embraced a multidisciplinary approach to research and undertaken intensive study in some of today's most vital fields. TUS is a meritocracy where the best in science is recognized and nurtured. It is the only private university in Japan that has produced a Nobel Prize winner and the only private university in Asia to produce Nobel Prize winners within the natural sciences field.

Website: https://www.tus.ac.jp/en/mediarelations/

About Professor Hidenori Otsuka from Tokyo University of Science

Prof Hidenori Otsuka completed his Ph.D. from the Division of Natural Science Chemistry, Tokyo University of Science (TUS) Graduate School, and currently heads his own laboratory at TUS. With more than 100 research publications to his credit, his research focuses mainly on the basics and applications of physical chemistry, especially colloid and surface chemistry.

Funding information

This research was supported by the Science Research Promotion Fund "S19-707-00" from the Promotion and Mutual Aid Corporation for Private Schools of Japan (PMAC) and the Grant-in-Aid for JSPS Fellows "19J13789" from Japan Society for Promotion of Science (JSPS).

Tokyo University of Science

Related Regenerative Medicine Articles from Brightsurf:

Stem cells: new insights for future regenerative medicine approaches
The study published in Open Biology unravels important data for a better understanding of the process of division in stem cells and for the development of safer ways to use them in medicine.

Engineered developmental signals could illuminate regenerative medicine
For a tiny embryo to develop into an adult organism, its cells must develop in precise patterns and interact with their neighbors in carefully orchestrated ways.

A new discovery in regenerative medicine
An international collaboration involving Monash University and Duke-NUS researchers have made an unexpected world-first stem cell discovery that may lead to new treatments for placenta complications during pregnancy.

New research into stem cell mutations could improve regenerative medicine
Research from the University of Sheffield has given new insight into the cause of mutations in pluripotent stem cells and potential ways of stopping these mutations from occurring.

Keratin scaffolds could advance regenerative medicine and tissue engineering for humans
Researchers at Mossakowski Medical Research Center of the Polish Academy of Science have developed a simple method for preparing 3D keratin scaffold models which can be used to study the regeneration of tissue.

NUS Medicine researchers can reprogramme cells to original state for regenerative medicine
Scientists from NUS Medicine have found a way to induce totipotency in embryonic cells that have already matured into pluripotency.

A new material for regenerative medicine capable to control cell immune response
Scientists of Tomsk Polytechnic University jointly with the University of Montana (USA) proposed a new promising material for regenerative medicine for recovery of damaged tissues and blood vessels.

Optoceutics: A new technique using light for regenerative medicine
Researchers in Italy at IIT-Istituto Italiano di Tecnologia used visible light together with photo-sensitive and biocompatible materials to facilitate the formation of new blood vessels in vitro.

Major stem cell discovery to boost research into development and regenerative medicine
A new approach has enabled researchers to create Expanded Potential Stem Cells (EPSCs) of both pig and human cells.

Spinning-prism microscope helps gather stem cells for regenerative medicine
Pluripotent stem cells are crucial to regenerative medicine, but better screening methods are needed to isolate safe and effective cells for medical use.

Read More: Regenerative Medicine News and Regenerative Medicine Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.