Introduction: Cancer begins and spreads with the uncontrolled growth of body cells. The simple definition of cancer disease is as follows: the uncontrolled growth of body cells begins with disregarding the normal rules of cell division in the body. Normal cells of the body are constantly producing signals that indicate whether this cell should divide or differentiate into another cell or the life of this cell has ended. But cancer cells do not pay attention to these signals or they themselves produce these signals and are self-sufficient, which causes the uncontrolled growth of those cells and causes cancer [2].
Diagnosis and prevention of cancer is usually diagnosed with genetic tests, and patients are tested and examined based on clinical indicators, pathology or family history that can be verified. Genetic testing can be used as a prediction guide. Early detection of cervical, colon and lung cancer and timely intervention for treatment can improve a significant number of them and reduce the number of deaths [3].
Colon cancer is the third most common cancer worldwide and the fourth leading cause of cancer-related death, and with nearly 1.4 million new cases and 700,000 deaths, the prevalence of colon cancer is projected to increase worldwide. It is an increase that is predicted to reach 2.4 million people by 2035. In terms of geographical distribution, it compares the Human Development Index (HDI) between developed and developing countries. In countries with moderate to high HDI, prevalence and mortality are increasing (Eastern Europe, Asia and South America). Stabilizing or reducing the death rate is only in very advanced countries (United States of America, Australia, New Zealand, etc.).
In the National Cancer Institute, colon cancer is defined as this, cancer is a disease in which the cells of the body divide abnormally without control and can attack the surrounding tissues. These cells can also spread to the affected parts of the body with the help of the blood and lymphatic systems. Colon cancer forms in the tissues of the colon. Rectal cancer and colon cancer are generally grouped together because they have many characteristics in common. There are many types of colon cancer, but about 96% of colon cancer is adenocarcinoma. Some other less common types of colon cancer include: Carcinoid Tumors that start in hormone-producing cells in the intestine. Gastrointestinal stromal tumors that develop in the interstitial cells of Cajal, in addition, sarcomas, which are very rare, can develop in blood vessels, muscles or connective tissues in the walls of the large intestine. Since most cancers are colorectal adenocarcinoma, we classify them into different groups. Adenocarcinoma begins in the epithelial tissues of the colon and intestine. Polyps are the most common precursor lesion of this type of cancer.
Mucus around the intestine can act as precursor lesions of colon cancer.
Countries that have diets high in fat, red meat, and refined grains, and the amount of fiber and fruit consumption in them is low, the probability of colon cancer is higher in that society, and in addition to the diet, their living environment also has a great impact on the amount of colon cancer. He has colon cancer. Even with the progress of colon cancer science, the rate of survival and recovery is slow. Colorectal cancer prevention is a main goal for public health in different societies. The effects of diet on the occurrence of colon cancer are related to the fact that the diet is such that it prevents intestinal inflammation and reduces the risk of colon cancer. Foods that increase inflammation are high-fat foods and red meat. Vegetables have been studied a lot because of their protective effects against colon cancer, and some of their mechanisms include: epigenetic and xenobiotic regulation of metabolism, inhibition of cell proliferation and tumorigenesis, and their antioxidant activity. A high-fat diet (60% fat) is the background of colon cancer [4].
Methods: Required equipments are pH meter, balance, ultrasonic bath, fluorescence microscope.
We use double distilled water to prepare solutions and dilute them.
In order to remove the metal impurities in the carbon nanotubes and make them hydrophilic, we have to place them in a 0.2 M nitric acid solution for 15 hours until the surface of the carbon nanotubes oxidizes.
Graphene oxide (GO) is obtained from graphite powder according to Hammer's method.
For the synthesis of graphene nanocomposite and gold nanoparticles (rGO-AuNP), the method provided by Wang et al. was used.
To measure the M2PK protein in feces, a number of stools from sick people should be collected and tested at different concentrations.
Aptamer synthesis is the first step towards the production of our biosensor. First, we need to determine the sequence of our aptamer. Our aptamer structure..Aptamer sequence. It is used to detect colon cancer cells. We have to add parts to the beginning and end of the aptam, at the end of three primes we add amino-C6 and at the end of five primes we add fluorescein isothiocyanate (FITC). FITC is used to detect the connection between cells and aptamer using flow cytometer and fluorescence microscope.
Aptamers are used for detection by chemically binding to our target cell or tissue.
Four steps are used to create a link:
1) Creation of thiol group with 11-MUA coating on the electrode.
2) Activation of the COOH group in 11-MUA with ethyl (dimethylaminopropyl) carbodiamide (EDC) / N-hydroxysuccinimide (NHS).
3) binding with NH2 at the apex end of the aptamer.
4) coating with bovine serum albumin (BSA) to prevent non-specific binding.
Before starting the diagnosis, we clean the electrode through the following four steps.
1) In order to bind thiol groups on the surface of the electrode, we place the electrode in ethanol/H2O solution at a ratio of 1/3 (V/V) for 18 hours. After 18 hours, we dry the solution with nitrogen gas.
2) N-hydroxysuccinimide (NHS) and N-ethyl-N-(3-diethylaminopropyl) carbodiimide (EDC) are used. EDC is used as a cross-linker to form the amide bond, and NHS is used to activate the carboxyl group attached to EDC. We immerse the gold electrode in phosphate buffer containing salt (PBS) for 1 hour. This buffer, adjusted to pH 4.7, contains 2 mM EDC and 5 mM NHS.
3) After that, we immerse the electrode in Tris-HCl buffer for 2 hours. This buffer is adjusted to pH 7.6 and the ionic strength I is set to 0.14 and contains 0.4 μM of aptamer.
4) To prevent non-specific binding, we immerse the electrodes in distilled water containing 1% BSA for half an hour. We also put it in Tris-HCl buffer for 10 minutes to remove unlimited BSA.
We use several different cells to verify the performance of the apta sensor to find out the level of aptamer working properly.
Flow cytometry and fluorescence microscopy are used to evaluate the binding between aptamer and cells. For this purpose, we use FITC as a functional fluorescein molecule with an isothiocyanate reactive group (N = C = S), with the peak wavelength of the excitation and emission spectrum from 495 to 519 nm. After determining the desired range of detectable current, we determine the positive and negative control of these tests
All electrochemical measurements are performed at 25 °C in PBS containing K3 [Fe(CN)6] at a concentration of 1 mM]. PBS adjusted to pH 4.7 was used as electrolyte. In this measurement method, cyclic voltammetry (CV) is used as an electrochemical method.
The connection of colon cancer cells to aptamer using fluorescence microscope and using microscopic images has already been diagnosed.
Flow cytometry is the best method to confirm binding between target cells and aptamer. Using negative and positive control cells, we distinguish. By comparing the control chart, we distinguish between positive and negative.
We examine different concentrations of 12, 25, 50, 100, 1000, 17000 cells per milliliter to find the best concentration for cancer detection [1].
Results: According to the research done by different people and scientists, different methods have been identified to diagnose colon cancer. Each of these methods has its own characteristics. But some methods cause late diagnosis and other treatment methods are not working and the cancer has progressed a lot. But this method of tests done by different people has shown that it has the ability to identify in the first stages, which helps both the treatment of the person and the doctors to choose the right treatment and to treat the person in a shorter time. advance
Conclusion: According to the studies, this method has the ability to identify a person's disease in the first stages, which helps both the treatment of the person and the doctors to choose the right treatment and to advance the treatment of the person in a shorter time. Due to its accurate sensors and specific identifiers, this method can correctly diagnose the disease and reduce the additional costs of the person and make it a much better result of the treatment. Of course, this method required more and more detailed laboratory research.
Keywords: Cancer - large intestine - nanoparticles - colon cancer