합성생물학

Synthetic biology combines biology and engineering to create or redesign biological entities, organisms, or pathways. The primary objective is to use biology as a tool to create new molecules and organisms, similar to how an electrical engineer builds functional circuits from individual components. Researchers aim to create programmable microorganisms from scratch using individual cell components to solve real-world problems.

Transfection is the process of inserting genetic material such as DNA or RNA into mammalian cells. When the same technique is performed on bacterial cells, it is called transformation. Both methods use positively charged carrier molecules or liposomes to deliver genetic material across the negatively charged cell membrane via endocytosis.

Electroporation uses an electrode to create tiny pores in the cell membrane, allowing DNA to pass through. Cells and RNA are loaded into a pipette electrode tip with electrolytic buffer in a glass cuvette. A pulsed voltage of approximately 1500 volts is applied to open the membrane temporarily. After electroporation, cells are mixed with culture media and either used or stored for further experimentation.

The heat shock method begins with chemically competent cells thawed on ice and mixed with cold plasmid DNA. The mixture is incubated on ice for 30 minutes, then placed in a 42-degree Celsius water bath for 30 seconds. Cells are immediately returned to ice, fresh media is added, and the mixture is incubated at 37 degrees Celsius for one hour to allow recovery. Cells are then cultured on antibiotic-containing agar plates overnight to identify successful transformants.

DNA sequencing allows researchers to identify specific gene functions in organisms with desirable traits. Once identified, the exact DNA sequence can be synthesized in large amounts and used to genetically modify cells through transfection or transformation. This capability enables scientists to isolate and replicate beneficial genetic information, making it possible to engineer custom organisms for specific applications.

Synthetic biology has diverse applications including environmental cleanup, where genetically engineered bacteria break down oil residues and specific pollutants at lower costs than traditional labor-intensive methods. In medicine, synthetically constructed organisms can be engineered to diagnose and treat diseases like cancer by responding to cancer cell signatures and targeting infected cells for treatment. These engineered systems support upstream and downstream bioprocess engineering for scaled production.

During transfection, DNA is complexed with positively charged carrier molecules or condensed within positively charged liposomes or polymer particles such as polyethyleneimine. The positively charged complex attaches to the negatively charged cell membrane and enters via endocytosis, a process using membrane-bound vesicles called endosomes. Once inside, genetic material leaves the endosome and enters the nucleus where cellular machinery produces mRNA and protein.