1. Introduction

• SF9Insect cells are an important eukaryotic cell line derived from the ovarian tissue of armyworm pupae in grasslands. Their cultivation principle is to simulate the physiological environment inside insects (suitable temperature, nutrition, and gas exchange) to support cell proliferation and serve as hosts for rod-shaped viruses, thereby achieving high-level expression of recombinant proteins.

Common configurations:

• temperature27℃

• Speed:120-140 rpm(Suspension culture)

2、 Plan Details

• Typical scenario:

SF9The main application of cells is to interact with rod-shaped virus expression systems, such asBac-to-BacThe combination of systems is an important tool for high-level expression of complex recombinant proteins, virus like particles, and vaccine antigens in biopharmaceuticals and basic research.

• Configuration parameters and principles:

temperatureSF9The cultivation temperature of cells must be strictly controlled within26-28Between ℃, usually set as27℃. This is because cells derived from insects have a much lower optimal growth temperature than mammalian cells. Temperature is a key factor affecting cell growth and protein expression. Once the cultivation temperature exceeds30At ℃, it will lead to cellular heat stress, growth arrest, and even large-scale death, causing irreversible damage. Therefore, temperature calibration and continuous monitoring of the incubator are crucial

Speed:When conducting suspension culture, the rotational speed is usually set at120to140 rpmWithin the scope. This rotational speed ensures that cells are evenly suspended in the culture medium, avoiding settling, while providing sufficient gas exchange (oxygen transfer) for cell growth. Low rotational speed can lead to cell aggregation and hypoxia; If it is too high, it will generate excessive shear force, causing mechanical damage to cells. In addition, to ensure gas exchange efficiency, the cultivation volume generally does not exceed the total capacity of the shaking flask2/5.

• Precautions and operating points:

conductSF9During cell culture, the following steps require special attention:

1. Temperature sensitivity:SF9Cells are extremely sensitive to temperature. The cultivation temperature must not be higher than30℃, otherwise it will cause irreversible damage to cells. Even during operations such as recovery and brief detachment from the culture environment, they should be completed as soon as possible to avoid prolonged exposure to room temperature or higher temperatures.

2. Avoid mechanical damage:SF9Cells are highly sensitive to mechanical forces such as blowing and bubbles. All operations, such as resuspension and passage blowing, must be performed gently, avoiding the generation of too many bubbles as much as possible to maintain high cell vitality.

3. Observation of cell morphology:Observing some black particles inside the cells during the cultivation process is a normal phenomenon, which is due to the secretion vesicles and organelles of the cells themselves. After a period of adherent culture, some cells may extend longer antennae, which is not a sign of contamination or poor condition. If there is an increase in extracellular debris, it can be removed by low-speed centrifugation and fluid exchange.

4. Recovery and Cryopreservation:After recovery, it is recommended to24Replace the fresh culture medium once every hour to remove harmful substances released by dead cells. It is recommended to use a programmed cooling box during cryopreservation and regularly revive and check the activity of the stored cells to ensure the quality of the seed cell bank.

3、 Source of Literature

1. O'Reilly, D. R., Miller, L. K., & Luckow, V. A. (1992). Baculovirus Expression Vectors: A Laboratory Manual. W.H. Freeman and Company

   Explanation: This book is a classic manual in the field of baculovirus expression systems, providing detailed explanations includingSF9The basic biology, cultivation methods, transfection, and infection experimental procedures of insect cell lines.

2. Luckow, V. A., & Summers, M. D. (1988). Trends in the development of baculovirus expression vectors. *Bio/Technology, 6*(1), 47-55.

   Explanation: This highly influential review article systematically reviews the development history of baculovirus vectors and clarifies thatSF9The key role of cell lines in system optimization.