I can extract side effects

Kunming, Sanqing Headquarters.

Xue Shen lay in front of the computer, his fingers flying, and the crackling sound of the keyboard resounded throughout the office.

After a long time, he stopped, clicked the mouse in satisfaction, and sent a long email.

"For more than three months, the animal experiment of the artificial blood vessel on pigs has finally been completed, and the experiment report has been uploaded, and the next step is to wait for its clinical application in humans."

"Time flies so fast, a year has passed in the blink of an eye."

He looked at the calendar, it happened to be the last working day of the year, and he couldn't help but let out a long sigh.

"Fortunately, the two major projects this year have been very successful. Mr. Wei should be very satisfied. The promotion and salary increase will probably be put on the agenda."

Xue Shen thought happily, and couldn't help grinning.

Tuk tuk tuk!

Suddenly someone knocked on the door.

Xue Shen quickly restrained his smile, sat upright, and shouted: "Please come in."

A young man with a handsome face came in, and through thick glasses, the eyes of the two met.

Surprise flashed across Xue Shen's eyes, and a smile quickly formed on his face: "Ding Bo, it's you, you are a rare visitor, please sit down."

Ding Mian sat down opposite, and said hello very politely: "Xue Bo, hello, I have known you for a long time, it is a pleasure to meet you."

He didn't waste time, and went straight to the point: "Everyone is engaged in scientific research, so I won't talk about those silly things. I heard that your artificial blood vessel project is progressing well? Have you finished the animal experiments? "

Xue Shen's thoughts changed. He didn't mind if the other party spoke directly, but the progress of the artificial blood vessel project was an internal secret.

So he smiled slightly and said, "That's right, did Mr. Wei tell you? I'm going to apply for a clinical trial next step."

Ding Mian slapped his thigh, overjoyed: "Great, that means this project is a success, it seems that I came here at the right time."

Xue Shen chuckled and said, "You don't seem to have explained your reason for coming."

Ding Mian came over and said excitedly: "You should know about my stem cell laboratory. I had an artificial blood project in my hand before, and it will be on the market at the end of the year. It is almost completed."

"Then I was thinking about what to do for the next project, Mr. Wei gave me a few words, and immediately saw the light of day, and let me suddenly see the light."

"He said that artificial organ transplantation is inseparable from nanotechnology. It just so happens that the artificial blood vessel project in your hand is also an artificial organ. If I have any ideas, I can come and discuss with you. Maybe there will be new gains."

"As soon as I heard about artificial blood vessels, a flash of inspiration flashed in my mind, and the next project will be ready immediately."

Knowing that the other party is an expert in stem cell research and has a successful project in hand, Xue Shen asked immediately, "What new project? Is it related to artificial blood vessels?"

Ding Mian did not answer right away, but instead asked, "How much do you know about tissue engineering?"

Xue Shen shook his head slowly: "I've heard of it, but I haven't majored in this field, because I have a background in physics, which can't be compared with your biology class."

"Then do you know the different stages of development of artificial organs?" Ding Mian continued to ask.

Xue Shen spread his hands and looked at him with a smile without saying a word.

Seeing this, Ding Mian didn't ask any more questions, but continued to talk incessantly.

"You know, in the scientific community, it is still an unattainable goal to fully manufacture the most complex human organs, but great progress has been made in the construction of many special tissues."

"The holy grail in the field of artificial organs is to create solid organs like hearts, kidneys, lungs and livers."

"Then there are hollow, non-tubular structures like bladders, which are at the next level of difficulty."

"Further down, the difficulty is decreasing, which is to create tubular structures, such as blood vessels and trachea."

"As for the simplest organs that humans can make, they are all flat and relatively hard, such as skin and cornea."

Xue Shen nodded: "So what you want to say? We have created artificial blood vessels, which belong to the third level of difficulty."

Ding Mian waved his hand and said: "Actually, the difficulty level is not divided in this way. Solid organs and tubular structures look very close, with only one level between them, but the difficulty between the two is far greater than people imagined. It could be a gap from 0 to 1."

Xue Shen asked with interest: "Then where is the key difficulty between them?"

Ding Mian's face became serious, and he said in a deep voice, "This involves the knowledge of tissue engineering."

"Maybe most people hear this name and think it is a management or engineering term, but it is indeed a biological term."

"The tissue here refers to multi-layered human tissues, such as nanoscale proteins, micron-scale cells, millimeter-scale blood vessels, and centimeter-scale viscera, which eventually grow into the entire body."

"Tissue engineering refers to the analysis of tissue structure and reconstruction of human tissue through physical and chemical means."

"In human tissue, cells are arranged in a very complex way, forming more or less symmetrical three-dimensional structures."

"In most cases, they are embedded in a complex network of active nanostructural 'cables,' a scaffolding of proteins that we call the extracellular matrix."

"The extracellular matrix provides an environment with structural, physical, mechanical, and biochemical properties that supports cell growth and interactions within tissues."

"The extracellular matrix is ​​a living gel, secreted by cells, that contains a large number of fibrous proteins and sugars, including collagen, elastin, hyaluronic acid, and proteoglycans."

"When we are injured, the extracellular matrix is ​​destroyed. When the cells move to the trauma site, the information of the extracellular matrix is ​​lost, so the cells will create scar tissue to fill in the gaps. The scar tissue will be harder. And it's inconsistent with other structures."

"It was realized a long time ago that to grow human tissue, you have to recreate the environment originally provided by the extracellular matrix by generating artificial scaffolds on which to seed cells."

"This artificial scaffold has to have the right structure for cells to attach to, survive, evolve and divide."

"It must also be biocompatible and be able to transmit physical and chemical signals to direct cell differentiation."

"For example, the skeleton of the human body is a special scaffold woven of collagen and other fibrous proteins, where mineral calcium phosphate salts can be deposited to form a strong bone."

"Bone fuses proteins and minerals at the nanometer scale to achieve its special mechanical properties. It is both strong and elastic, able to resist damage and cracks caused by enemies or accidents, and to be well prepared for growth and regeneration. Prepare."

"That's the secret of being able to rebuild and heal after a fracture."

"As a result, artificial bone graft materials have been developed, as well as artificial skin and so on."

"These cases represent the emergence of a new discipline, tissue engineering."

"The ability to manipulate pluripotent stem cells to differentiate into any desired tissue is the ultimate goal pursued by this field."

"However, human beings are still unable to do this, so they can only settle for the next best thing, but it is also very difficult to use artificial scaffolds to construct fully functional tissues."

"There are two main difficulties."

When Ding Mian said this, he coughed twice, picked up the tea brought by the secretary, and took a big gulp.

Xue Shen was engrossed in listening, and urged repeatedly: "What's next? Continue."

"One of the main problems is that the diffusion of nutrients and oxygen in artificial structures is very difficult to achieve."

"This means that it is feasible to construct functional small cell structures of a few microns, and in fact we have also developed such miniature human tissue structures, called organoids."

"But trying to make them bigger and still active is difficult because oxygen and essential nutrients can't reach the cellular level."

"Transportation in real tissue is enabled by a very complex interplay of biological and physical mechanisms, including angiogenesis, which can continuously deliver oxygen and nutrients to cells in a very dense environment."

"Delivering nutrients to cells and removing waste products is only possible when the distance between cells and capillaries is less than 200 microns."

"So, the generation of blood vessels in artificial organs has always been a thorny biological and engineering problem."

"Another difficulty lies in finding the right source of cells to provide a sufficient number of cells to eventually generate large tissues of medical significance."

"Currently, most of the artificial organ transplants have a donor, and most of them are dead people, because this type does not require strict matching."

"Scientists take the donor's organ, remove the donor cells on it, leave a tissue scaffold, and then implant the recipient's cells, so that a transplant can be completed."

"After a long time, the donor's scaffold will degrade in the body, and new cells and blood vessels will grow out to completely form a new organ."

Xue Shen couldn't help but interjected, "It's like artificial blood vessels."

Ding Mian nodded, and concluded: "Yes, so now the difficulty of artificial organs is very clear."

"First of all, we can't grow a whole solid organ from scratch using stem cells, whether it's a heart, or a kidney, or a liver."

"So, we can only make an artificial scaffold, which can be biomaterials, polymer materials, metal materials, or even organs from dead people or animals."

"Next, we plant the cells we need, which can be nerve cells, cardiomyocytes, retinal cells, and any other cells."

"Then we're stuck here because we can't make this organ as big as a real organ without a lot of cells."

"This point may be solved by pluripotent stem cell differentiation technology in the future. In short, I am still confident."

"Then if this difficulty is solved, we can culture a large number of cells, all of which come from the same receptor, so there is no immune response, and the conditions are perfect."

"Next, we encountered a fatal difficulty, that is, artificial organs have no blood supply. All the cells are clustered together and grow comfortably in a network of extracellular matrix, but without nutrients and oxygen arriving, they quickly will die."

"There is no solution for this yet. Some relatively simple small organs can be connected to human arms or thighs, and use the human body's own growth ability to grow blood vessels and nerves to solve this problem."

"But for large organs, there is still no solution."

Xue Shen said thoughtfully: "When you say that, I understand that it is indeed very difficult."

He laughed immediately: "Now that we know where the difficulties are, at least we have a goal to work on, don't we? As long as we keep working hard in the direction, we will solve these difficulties sooner or later."

"Papa papa!" Ding Mian clapped his hands and praised loudly: "That's right, your attitude is exactly the spirit of my generation of scientific researchers. I knew at a glance that I didn't find the wrong person this time."

He rubbed his forehead and said a little embarrassedly: "By the way, I don't seem to have had time to say that my new project is the artificial bladder project."

"Artificial bladder?" Xue Shen was taken aback, and then became excited: "So this is what you said at the beginning. This is a hollow non-tubular structure, and it is very difficult. Are you sure?"

Ding Mian nodded, shook his head again, and said, "It's hard to say, I only have a rough idea."

"Let's hear it?" Xue Shen stretched out his hand again.

Ding Mian adjusted his glasses and talked eloquently.

"There have been clinical cases of artificial bladder cultivation and transplantation in foreign countries, but it has not yet been popularized. There is no precedent in China. For patients who need to remove the bladder, the common surgical plan is to intercept a section of large intestine and then transform it into a bladder. Then sew the ureter back on."

"There are many clinical limitations. Some patients' intestines are not healthy and cannot be intercepted. Another long-term use will also cause some problems."

"The artificial bladder transplantation technology can perfectly solve the patient's troubles. It does not require autologous material, and there is no restriction on the patient's physical condition."

"This new bladder is imitated from a real bladder. It is composed of three layers of material. The outer layer is muscle, the inner layer is bladder epithelium, and the middle is the tissue protein collagen that plays a connecting role. It needs a certain degree of elasticity. The whole structure looks It looks very much like a baked layer cake."

"I told you just now that the acquisition and cultivation of cells is not difficult, as long as some live cell samples are taken from the patient's bladder, and the muscle cells and bladder epithelial cells are cultured separately."

"After the cells are cultured, they will be placed on a bladder-shaped biodegradable bioscaffold. After the entire new bladder is cultivated, it will be transplanted into the patient's body."

"Since the bladder is a very small mass and hollow when it contracts, it does not need many cells, so it is a relatively easy choice."

"If all goes well, the artificial bladder can work like a normal bladder in the patient's body within a month at most. After a few months, the biodegradable scaffold will be decomposed, and blood vessels and nerves will grow on the artificial bladder to connect with the surrounding tissue. stand up."

"During the whole process, the techniques of transplantation and cell culture are very mature, and I can do it."

"The only difficulty lies in the biological stent, but after the success of the artificial blood vessel research, it was also solved."

"I have seen the performance parameters of artificial blood vessels. The elastin protein used in it is very suitable for artificial bladders, which can provide several times higher elasticity than normal bladders, so they can better control urination and significantly improve patients' symptoms of urinary incontinence."

"The biomaterial just needed a few tweaks to make it a perfect fit for the artificial bladder project."

"What do you think?" Ding Mian stretched out his hand excitedly, and said expectantly, "Do you want to do it together?"

Xue Shen suddenly smiled, held the other's hand tightly, and said firmly.

"No problem, Ding Bo, this time it's up to you to lead the flight."