213: Chapter 213 Cultivating Centrifuges

When Chen Youhua arrived at the Medical School, Teacher Zhou was outside the Cell Culture Room changing his shoes.

“You're here?” Teacher Zhou didn't even look up. “Come in, the shoe covers are on the left.”

Chen Youhua put on the shoe covers, donned a white lab coat, and followed Teacher Zhou into the Cell Culture Room, which was very clean.

Two graduate students were working; they glanced up when they saw someone enter, then lowered their heads to continue their work.

“I've looked at the proposal you mentioned.” Teacher Zhou walked to the Clean Bench, reached inside, and wiped his hands with an alcohol cotton ball. “An Autologous Cell Membrane Coating is a good idea. But how do you plan to do it?”

Chen Youhua stood beside him and also reached in to wipe his hands. His movements were very practiced, even faster than Teacher Zhou's.

“First, culture the cells. Once enough have grown, lyse them, extract the membranes, and coat them onto the electrodes,” he said. “I'll use Fibroblasts; they're easy to culture and grow quickly.”

Teacher Zhou glanced at him. “Have you cultured cells before?”

“I have. I started in my freshman year. Cancer cells, primary neurons, engineered bacteria—I've cultured them all.”

Teacher Zhou was stunned for a moment, then smiled. “I forgot, you're a biology student. Fine, do it yourself then. You can use this Clean Bench, and there's an empty shelf in the Incubator. The cell lines are in the refrigerator; help yourself.”

Chen Youhua nodded and took out a tube of cryopreserved Fibroblasts from the refrigerator.

A chilly mist of liquid nitrogen billowed out. He placed the cell tube into a water bath at 37 degrees for two minutes.

Then he took it to the Clean Bench, opened it, used a Pipette to transfer the cell suspension into a Culture Flask, added Culture Medium, capped it, and gave it a gentle shake.

Teacher Zhou stood by and watched without saying a word.

He had originally prepared a bellyful of instructions to teach this 'cross-disciplinary' mathematics professor, but now it seemed they weren't needed. Chen Youhua's technique was even more efficient than that of his graduate students.

“Done.” Chen Youhua placed the Culture Flask into the Incubator. “I'll passage them tomorrow. They should grow enough in about a week.”

“A week?” Teacher Zhou thought for a moment. “That's too fast. You want the cell membranes, not just cell quantity. If they grow too fast, they age easily, and the quality of the membranes will decline.”

“Then slower?”

“Slower. Lower the serum concentration and let them grow gradually. They'll be in the best condition in about ten days.”

Chen Youhua nodded and turned the Incubator's temperature down by one degree.

“You're quite familiar with cells,” Teacher Zhou remarked.

“I did experiments for a few years.” Chen Youhua closed the Incubator door. “The prosthetic limb project was in the biological direction.”

“I know. But wasn't that about nerves and materials? You did the hands-on work too?”

“I did everything in the early stages. Later, when I got too busy, I handed it over to Wang Zhe and Li Wei.”

Teacher Zhou glanced at him and said nothing more.

He had originally thought this young mathematics professor had come to him to learn techniques, but now it seemed he was here to find a collaborator.

“Alright,” Teacher Zhou said. “You culture the cells and extract the membranes yourself. I'll keep an eye on things and remind you if there are any issues. You handle the electrodes, and I'll help you adjust the parameters when it's time for the coating.”

“Okay.”

...

For the next week, Chen Youhua's life became very regular.

He arrived at the Medical School at 8:00 AM to check the cells. They were growing well, at a steady pace, and looked to be in good condition.

He changed the Culture Medium once, reducing the serum concentration by half. Teacher Zhou glanced at it while passing by and nodded.

Then he went to the School of Materials to make the electrodes.

He was already very familiar with that ALD machine; once the parameters were set and the button was pressed, all that was left was to wait.

While waiting, he read papers on synaptic plasticity, which gave him a headache.

At noon, Wang Zhe brought him lunch.

“You skipped breakfast again today.” Wang Zhe placed the lunchbox on the table.

“I ate. A piece of bread.”

“Bread doesn't count as breakfast.”

“It counts.”

Wang Zhe sighed and sat beside him, watching him eat.

Today he had brought braised pork from the cafeteria; it was a bit salty, but Chen Youhua ate with gusto.

“How are the cells growing?” Wang Zhe asked.

“Okay. They'll be ready in another three or four days.”

“And the electrodes?”

“I made three batches; two failed. The third batch is okay. I'm going to test its performance this afternoon.”

“Do you want me to come help?” he asked.

“No need.” Chen Youhua put down the lunchbox. “The prosthetic project is enough to keep you busy. Is the expansion of cooperation with the military settled?”

“Pretty much. The first roster has been finalized, and surgeries will start next month.”

“That's good.”

Wang Zhe stood up and patted his shoulder. “Let me know if you need anything.”

“Okay.”

...

Ten days later, the cells had grown enough.

Chen Youhua stood before the Clean Bench, aspirated the medium from the Culture Flask, and washed it twice with PBS. His movements were very light and steady.

Teacher Zhou stood nearby watching, silent.

“Add Trypsin?” Chen Youhua asked.

“Add it. One milliliter. Digest for three minutes.”

After adding the Trypsin, Chen Youhua placed the Culture Flask back into the Incubator.

He took it out three minutes later and glanced at it under the microscope. The cells had already detached from the bottom of the flask, floating in the liquid as round spheres.

“Alright. Add Culture Medium to terminate the digestion.”

After adding the medium, he aspirated the cell suspension into a Centrifuge Tube.

“Lysis next?” he asked.

“Yeah. Aspirate the supernatant, then add the Lysis Buffer. Leave it on ice for thirty minutes.”

Chen Youhua did as instructed. After the Lysis Buffer was added, the liquid became turbid. He looked at the tube, then at Teacher Zhou.

“Wait,” Teacher Zhou said.

Thirty minutes later, he placed the tube into the Ultracentrifuge.

Ten thousand RPM, thirty minutes, four degrees. As the machine spun up, it made a loud noise, and the floor vibrated.

“Have you extracted cell membranes before?” Teacher Zhou asked.

“No. I've extracted proteins and DNA, but never membranes.”

“That's different. Proteins and DNA are molecules, while membranes are structures. You have to be careful when extracting them; if you're too violent, you'll shatter the membranes.”

“Won't the Lysis Buffer shatter them?”

“It will. But the Lysis Buffer breaks the cell membrane into fragments, not molecules. What you want are the fragments, not the molecules.”

Chen Youhua nodded.

Thirty minutes later, he took out the tube. At the bottom was a thin layer of precipitate, almost invisible.

“Is this the cell membrane?” he asked.

“Yes. Now resuspend it in buffer, and it's ready to use.”

Chen Youhua used a Pipette to pick up the pellet and added it to a small tube of buffer.

The liquid became slightly cloudy, like watered-down milk.

“Where are the electrodes?” Teacher Zhou asked.

“At the School of Materials. I'll go get them this afternoon.”

“Fine. Come over this afternoon, and I'll help you coat them.”

In the afternoon, Chen Youhua returned to the Medical School with the electrodes.

The electrodes were finished, featuring sixteen contacts, each thinner than a strand of hair.

He had spent two weeks and wasted over a dozen batches; this was the only usable set.

Teacher Zhou examined the electrodes under the microscope and nodded.

“The contacts are fine. Now put them into the cell membrane suspension.”

Chen Youhua used tweezers to pick up the electrodes and carefully placed them into the small tube containing the cell membranes.

“How long should I leave them?”

“Thirty minutes. Let the membrane fragments adsorb naturally.”

Thirty minutes later, Teacher Zhou took out the electrodes and placed them under the microscope. The surface of the contacts had a thin layer of something that shimmered with a faint glow under the light.

“It's coated,” Teacher Zhou said. “Now, let's test the immune response.”

He placed the electrodes into a Petri dish containing a type of immune cell: Macrophages.

The task of these cells was to engulf anything 'foreign'.

“Wait twenty-four hours,” Teacher Zhou said. “Come back tomorrow to see.”