Electrospinning combined with 3D printing: from imagination to reality

In recent years, news reports about 3D printing have often been seen: hospitals use 3D printing to customize organ models that fit the patient's size, and a creative team creates thin, paper-like LED lights... General Electric Company has pointed out that 50 3D printing technology will be able to successfully print an aero engine during the year. 3D printing technology has been recognized as one of the core technologies of the third industrial revolution.

3D printing is a kind of rapid prototyping technology. It is a rapid prototyping technology that constructs objects by layer-by-layer printing based on digital model files and using adhesive properties such as engineering plastics or metal powders. This technology simplifies product manufacturing processes, shortens product development cycles, improves efficiency and reduces costs. It can be widely used in medical, cultural, defense, aerospace, automotive and metal manufacturing industries. It is considered to be a major technology in the manufacturing field in the past 20 years. Results.

According to the principle of printing technology and the materials used, 3D printing technology can be divided into laser cladding molding technology (LCF), fused deposition rapid prototyping (FDM), selective laser sintering (SLS), stereo curing technology (SLA). ), three-dimensional printing molding (3DP) and the like. However, the wire scales that these traditional 3D printing technologies can print can only be up to the millimeter level, and the surface of the printed products is still rough, which does not achieve the best effect. In addition, some biological products are subjected to high-temperature sintering by 3D printing. Or fused deposition leads to a decrease in biological activity, which limits its application, so researchers are turning their attention to deeper applications and technologies. So the electrospinning technology we are familiar with has begun to enter people's imagination.

In the electrospinning industry, 3D printing has also received more and more attention. Researchers have begun to think about how to combine the equally important electrospinning with 3D printing to change the dimensional defects of 3D printing. Electrospinning expands from a simple two-dimensional structure of film, wire, and tape to a three-dimensional structure. Thus, 3D printing combined with electrospinning slowly begins to emerge from the imagination of the researchers, and into reality, some technologies are beginning to be applied.

3D bio-printing technology is one of the most advanced and most concerned areas in current 3D printing technology. Due to its individual characteristics, 3D printing can be widely used in biomedical applications, including cell printing, tissue engineering scaffolds and implants, and dentistry. Although bio 3D printing technology has advantages over other traditional processes in the manufacture of biodegradable three-dimensional structures, several mature 3D printing processes such as SLS, SLA and 3DP often use high temperature sintering and spray bonding. The auxiliary forming means such as the agent can cause the biological activity of the material to be destroyed, which greatly limits the application of these methods in the fields of tissue engineering, biomedicine and the like. To this end, bio-incremental extrusion forming technology and electrospinning technology based on the principle of 3D printing have been proposed and received extensive attention from scholars at home and abroad.

3D printed cartilage

Professor Dietmar W. Hutmacher of the Queensland University of Technology in Australia published "Reinforcement of hydrogels using three-dimensionally printed microfibres" in Nature Communications, detailing how to use biocompatible materials to more effectively repair human tissue, especially It is articular cartilage. Because cartilage requires both mechanical strength and flexibility, the researchers tested a new hydrogel and microfiber scaffold synthetic material to meet this requirement. Researchers have used a new 3D printing technology, melt electrospinning writing, which is a process in which a charged polymer melt is formed into a jet in an electrostatic field to produce a polymer super A method of processing fine fibers that helps provide space for cell growth while also contributing to the mechanical rigidity required of the cells. The resulting printed structure not only achieves natural healing, but also promotes the growth of new tissues. This 3D printing technology based on the principle of electrospinning opens the door for biomedical researchers.

3D printing absorbable blood vessel stent

"Physical chemistry chemical physics" (Phys.Chem.Chem.Phys., 2015, 17, 2996) was published by Professor Su A. Park of the Korea Institute of Machinery and Materials "Characterization and preparation of bio-tubular scaffolds for fabricating artificial vascular grafts by In the article "electrospins and a 3D printing system", it is mentioned in the literature that artificial blood vessels composed of natural polymer nanofibers are transplanted into the human body to promote the recovery of damaged blood vessels. However, biocompatible materials such as chitosan, which are electrospun nanofibers, lack good mechanical properties. Therefore, the design and manufacture of the researchers are divided into two steps. The first step is to prepare chitosan and PCL blend nanofiber scaffolds by electrospinning, and then the PCL chain is coated by 3D rapid prototyping technology to finally prepare artificial blood vessels. The artificial blood vessel manufactured by this method has excellent mechanical properties, and the method can be used for blood vessel reconstruction.

The Shanghai University Rapid Manufacturing Engineering Center has also made breakthroughs in biological 3D printing. Liu Yuanyuan of Shanghai University published a paper entitled "Composite bioabsorbable vascular stents via 3D bio-printing and electrospinning for treating stenotic vessels" in the June 2015 issue of Journal of Southeast University. A novel vascular stent was designed for the treatment of vascular stenosis. . Aiming at the shortcomings of equipment and technology for the preparation of bioabsorbable vascular stents, a new method for the preparation of composite bioabsorbable vascular stents by bio 3D printing and electrospinning was proposed. Firstly, the inner layer of the stent was prepared by 3D printing with PPDO material; then the mixed solution of chitosan and PVA was prepared, and the outer layer of the stent was prepared by electrospinning. The mechanical properties test showed that the stent prepared by combining 3D printing and electrospinning was better than only the stent. Ordinary bracket. The cell test on the scaffold showed that the cells had good adhesion and proliferation on the scaffold. The proposed composite forming process and method provided a good idea for the subsequent construction of the controllable drug-loaded scaffold.

3D printing clothing

At present, clothes printed with 3D printing technology are generally harder in texture and cannot be used for close-fitting clothing. Conventional electrospinning generally uses a high-voltage power supply. The distance between the Taylor cone and the receiving platform is large, and becomes a mass after spinning, making it difficult to control the orderly stacking. The team from San Francisco in the United States made the molding platform into a hanger shape and launched the world's first 3D electric looms, Electromoloom, which can automatically produce polyester fiber blended clothing. The principle of this 3D printer is similar to electrospinning. The CAD software is used to design the template. After the designed template is placed in the printing warehouse, the mixed liquid liquid solution is molded by the template under the guidance of the electromagnetic field. It is called "electrospinning". The printer then uniformly coats the blended nanofibers into a seamless fabric.

3D printed building

Professor Kim of Seoul National University in South Korea published an article entitled "Toward Nanoscale Three-Dimensional Printing: Nanowalls Built of Electrospun Nanofibers" in "Langmuir". They showcased independent nanowalls and other nanoscale 3D objects that can be constructed in 3D printing. A new method for electrostatically depositing polymer nanofibers in a precise and repetitive manner to create a specified object is presented.

Electrospinning is a relatively simple method of making polymer nanotubes. Nanoscale fiber flow is very confusing, and it is very difficult to control a single fiber. In their recent research work, it was found that the use of a thin metal electrode wire allows the nanoscale fiber flow to be relatively ordered. Using this line, the above polymer nanotubes can be stacked to form a wall structure. Studies have shown that the electrostatic interaction between the fiber and the metal wire can be used to balance the tension inside the polymer fiber, and the length of one nanowall can be controlled by controlling the translation of the base. The research team said that this novel 3D printing technology can be used in the development of biological stents, nanofilters, nanoelectrodes and the like.

Electrospinning has played a huge role in the field of tissue engineering scaffolding and energy storage. However, in the construction of various shapes, rapid prototyping technology is still needed. Therefore, the addition of 3D printing technology will undoubtedly enrich the application space of electrospinning. Come here, today's 3D printing technology can not get a big breakthrough in the size refinement problem, only on the millimeter scale, electrospinning technology solves the problem of wire size.