It is a great honour that Interface Focus will publish a special issue to introduce the progress and achievements of biomaterials research in China. We feel it is a good opportunity to present the progress in Chinese biomaterials research to the international biomaterials community, and to promote the collaboration between international and Chinese biomaterials scientists.
Although in ancient China, gold teeth and wood tools for bone repair have been recorded in literature, studies of contemporary biomaterials did not start until the beginning of the 1970s in China. Since then Chinese biomaterials research has developed rapidly: ‘Recently, Chinese biomaterials science and engineering have stepped into international stage successfully’ (A. F. Von Recum, Forum, SFB, 1997). At present, China has become one of the largest biomaterials research countries in the world .
There are close to 5000 professionals working in more than 300 institutes all over China, including universities, national and local research centres, company technology centres, hospitals, etc., from which the Chinese biomaterial R&D system is formed. These institutes are mainly concentrated in the metropolitan cities in China, such as Beijing, Tianjin, Shanghai, Wuhan, Chengdu, Guangzhou, Shenyang, Xi'an, Chongqing, etc. To date, close to 200 universities and colleges across the country have set up biomaterials programmes and more than 2000 undergraduate students are enrolled on biomaterials programmes in China.
The total funding allocated for the R&D of biomaterials has increased multiple times from 1990 to 2010, which mainly comes from central government, local government, companies and private investment. The Chinese Society for Biomaterials had been formed previously and is a founder of the International Union of Societies for Biomaterials Science and Engineering (IUSBSE). In 2010, there were about 1400 Chinese registered delegates of the National Biomaterials Congress of China. All these reflect the fact that R&D of biomaterials in China is well established.
The statistic results of published theses in 44 international journals on Biomedical Engineering (BME) from 1999 to 2008 show that China only accounted for 4 per cent of the total and is ranked in the seventh place. But the compound growth rate of published theses with a Chinese first author reached 40.5 per cent of the total theses and is ranked at the top. Chinese theses on materials and biomaterials published in the 44 journals are in third place. For 2010, Chinese theses published in three major international biomaterials journals were: 20 per cent of the total in the Journal of Materials Science: Materials in Medicine, 25 per cent in Biomaterials, and in first place in the Journal of Biomedical Material Research: Part A and Part B.
From 2003 to 2007, Chinese scientists have lodged 3431 patents in the field of medical devices, accounting for 3.4 per cent of the global total, ranking fifth out of 15 countries or regions. The compound growth rate of Chinese patents reached 36.1 per cent and is ranked first. The increased number of published Chinese theses and patents shows that the study of biomaterials science and engineering are very active in China.
The progress of Chinese biomaterials research has been further recognized by the international biomaterials community through the hosting of the 2012 9th World Biomaterials Congress in Chengdu, China.
Some major research areas and progress of Chinese biomaterials are summarized below.
2. Tissue-inducing biomaterials
We discovered and demonstrated that bone formation or regeneration could be induced by lifeless biomaterials themselves, other than by the addition of any living cells or growth factors, and proposed the osteoinductive mechanism of biomaterials. Based on this discovery, a new artificial bone material with osteoinduction was developed and obtained State Food and Drug Administration of China (SFDA) approval for access to the Chinese market. After that, an articular cartilage induced by a collagen-based hydrogel was also demonstrated. At present, the studies of tissue-inducing biomaterials have been extended to non-osseous tissue-inducing materials [2–4].
3. Surface and surface modification
These studies have focused on anticoagulation and antibiosis of biomaterials , and surface bioactivation.
3.1. Surface modification for improvement of anticoagulation
A viewpoint was raised that blood coagulation on the surface of biomaterials can be prevented. The key is to maintain the conformation stability of the core proteins in the coagulation system, so that the electrons on the active site of the protein molecular chain could not be transferred to the surface of implanted materials, thus preventing activation of the coagulation system.
According to the viewpoint, two kinds of anticoagulative surfaces have been developed.
3.1.1. Anticoagulative metal surface
The TiO2 film on the Ti surface was modified into a N-semiconductor using an ion immersion implantation technique, thus the electrons in the protein molecular chain could not be transferred onto the Ti surfaces. A comprehensive study showed that the Ti-modified surface has an excellent anticoagulation capability [6,7].
3.1.2. Anticoagulative polymer surface
By grafting amphoteric groups on a polymeric surface, an artificial blood vessel with excellent anticoagulation function was developed and is currently in clinical trial .
3.2. Surface bioactivation
A commercial plasma-sprayed hydroxyapatite coating has been developed and has been applied to artificial joint and dental implants since the end of 1980s in China .
The Ca-P thin film coating by bio-mineralization is being studied for artificial joints, percutaneous devices and porous metal implants with bioactive surfaces .
4. Tissue engineering
Regenerative medicine and tissue engineering are playing leading roles in the progress of biomaterials science and engineering. In China, studies of tissue engineering started at the end of 1990. Now, a batch of tissue engineering products for connective tissues is in clinical trials. Eight industry standards for tissue-engineered products have been issued by SFDA and the tissue-engineered skin has obtained approval from SFDA and is used in clinic [11–16].
5. Molecular biocompatibility
Molecular biocompatibility requires understanding of the biocompatibility of biomaterials at the molecular level, thus directing the design of a biomaterial with an expected biological response [17–19].
At this moment, the studies are focused on understanding the influence of a material's properties (signals) on cell behaviour, especially how materials can generate signals to be transmitted to the cells, and thus to regulate gene expression in cells and pathways of cell differentiation. Preliminarily studies have shown that some mechanical, electrical and geometrical properties, porous structure and surface patterning may affect the expression of genes and regulate cell behaviour.
A mineralized collagen fibril with structures like natural bone has been synthesized in vitro by the scientists from Tsinghua University. The nano-hydroxyapatite grains presented a periodic and oriented arrangement on the collagen fibrils. The study provided important evidence for the studies of the origin of natural bone and bone materials .
At the same time, the size of the Chinese biomaterials industry is increasing rapidly. The compound growth rate of the Chinese biomaterials market reached about 30 per cent between 2008 and 2010. The Chinese biomaterials market is worth US$9.85 billion. It is estimated that the Chinese biomaterials market will reach US$36.5 billion by 2015. The major driving forces to promote this growth are the discussed below.
First, the huge population and the big market, particularly the ageing population, promotes the increasing demand for medical devices in China. The population aged 65+ constitutes 8.3 per cent of total Chinese population and will increase to 32 per cent in 2020.
Second, the implementation of China's healthcare reform designed to improve healthcare access: by 2011, 90 per cent of the rural and urban population is expected to have basic insurance coverage through increased government subsidies. This will increase the demands for medical devices dramatically.
The third driving force is the rapid economic growth. In China, GDP growth has remained at about 9 per cent every year for the past 20 years. Healthcare expenditure also increases with rapid economic growth. The average healthcare expenditures of a middle-income family have increased 60 per cent in urban areas and 91 per cent in rural areas.
All of these factors will be the underlying impetuses to promote the vigorous development of biomaterials in China.
But the R&D level of Chinese biomaterials has to be further enhanced as mentioned above. The number of theses published in 44 BME journals by Chinese scientists was only 4 per cent of the global total, far below the USA (28.6%) and the UK (7%). The average citation per Chinese paper is 7.28, lower than that of American authors (11.45). Between 2003 and 2007, for published worldwide patents, the average number of citations per patent was only 0.07 for Chinese authors, much lower than the global average number of citations of 0.4, and is ranked 14. However, China was listed at fifth in the world for lodging patents and the rate of increase was at 36.1 per cent. China still has a long way to go to improve the level of biomaterials R&D. In particular the industrial scale and technological level have to be expanded and increased. The Chinese industrial scale of biomaterials is pretty small, and only accounts for less than 6 per cent of the worldwide biomaterials market. The technological structure of products is behind that of developed countries. About 80 per cent of the high-tech products rely on import. This situation cannot meet the basic demand to ensure healthcare for the Chinese people. At the same time, the capability of technology transfer is not efficient. Most of R&D achievements remain in laboratories and cannot be transformed to engineered technology or products. Still, there is a long way to go for Chinese biomaterials R&D compared to that of developed countries, regardless of its high speed of development.
In China, biomaterials research receives a great deal of attention and is listed as a priority science and technology area in the National Development Plan, which could change the current situation and meet all the basic demands of Chinese healthcare. A 10 year special development plan for biomaterials is being introduced. Our goals are to improve the quality and expand the production scale for general biomaterial and medical implants, and to enhance the capability of science and technological innovation, which could decrease the dependence on imported high-tech products. We hope the Chinese market of biomaterials and medical implants could at least reach US$36.5 billion by 2015.
We would like to express our appreciation to Prof. William Bonfield, the first editor of Journal of the Royal Society Interface, Prof. Denis Noble, editor of Interface Focus, and the Editorial Office.
One contribution of 11 to a Theme Issue ‘Biomaterials research in China’.
- Received March 16, 2012.
- Accepted March 16, 2012.
- This journal is © 2012 The Royal Society