The Safety Evaluation Of Graphene Quantum Dots For Hematopoietic System And Nervous System

Graphene quantum dots is composed of carbon atoms in the latest member of the family of grapheme, as a new type of quantum dots in biologicalnanomaterials,the quantum confinement effect and side effect could induce their self-fluorescence; By using the different chemical reactivity of oxygen reactive group, they could doing covalent reactions with different chemical groups and functional molecules which has the specific chemical and biological properties. Different synthesis methods or different particle size could generate different chemical properties. Surface functionalization modification of graphene quantum dots could reach to ultra high drug loading capacity, targeted delivery and the controlled release of drugs.Nanometer materials have become an indispensable hot topic in the 21 st century, Bring infinite interest and convenience as well as huge potential safety hazard. With different characteristics of nanomaterial effection, the influence of hematopoietic function and all kinds of hematopoietic cells are also different. Because of its small size make it can free access to most of biological tissue, achieving the treatment of lesion location at the same time also can damage cells. Nanomaterials could be transfered to the brain by a neural pathways or nerve endings. The nanomaterials in the nervous system may induce a variety of oxidative stress, inflammation, etc., cause a series of tissue damage.The central nervous system is responsible for sending, receiving, and interpreting information from all parts of the body which ensured the coordination of activities of the body organs and the unity and coordination between the body and the environment. The hematopoietic system is responsible for the continuous production of highly specialized mature circulating blood cells. Due to its high metabolic and proliferative rate, and because the functions performed by blood cells are vital to an organism, this system is highly susceptible to direct and indirect poisonous and harmful substances, and some drugs-induced injury. The effect of GQDs solution on the nervous system and hematopoietic system has important clinical significance for its wide application in the field of biological medicine.In this experiment subject through experiments in vivo and in vitro of rats, evaluated the influence of GQDs on hematopoietic function and the nervous system of rat in vivo and in vitro, in order to provide experimental reference for the clinical application of GQDs.Methods 1. GQDs solution configured to the drug concentration then processed with pasteurized.2. Experimental animal groups and methods: 2.1 In vivo 30 healthy male SD(Sprague wrote- Dawley) rats were divided into 3 groups at random(n = 10),Control group(normal saline)、Low dosage group(5mg/kg/d GQDs)、High dosage group(10mg/kg/d GQDs);breeding in three cages. Recorded each experimental rats weight after adaptive feeding in 7 days, injection GQDs into the tail vein. control group injected saline volume, continuous dosing 5 days, interval of 2 days to rest.28 days in total. and recorded the activity and behavior of experimental animals. Completed the open field test and Morris water maze test;the blood routine examination, functiong of liver and kidney in the serum were examined, the cell cycle and apoptosis of BMCs were deteced by the flow cytometry,the morphological change of brain and hippocampus of rats were observed by HE staining. 2.2 In vitro Took the humerus and femur tissue of SD male rats, cultured BMCs in vitro, pointed in GQDs with three groups:Control group with purified water; Low concentration group with 250ug/ml GQDs; High concentration with 500ug/ml GQDs solution in 48 h or 72 h. The effects of GQDs on BMCs was investigated by measurement of GM-CSF using Elisa and detection cell proliferation using OD value.Results:1. In the 10 mg/kg/d of the GQDs dose range, 1.1 experimental rat red blood cell and hemoglobin concentration increased significantly(p<0.05),the concentration of triglyceride and high density lipoprotein were decreased 1.2 DNA synthesis period was prolonged(p<0.01)in the cycle of BMCs, there was no significant difference in apoptosis 1.3 riglycerides and high-density protein concentrations decreased significantly(p<0.01). 2. BMCs were promoted proliferation clearly after using GQDs in different concentrations for 72h(p<0.05) 3. The content of GM-CSF on the BMCs supernatant was increased clearly after using GQDs(p<0.01)for 72 h. 4. The experimental rats weight continued to grow after the injection GQDs into the tail vein for 28 days.,compared with the control group, no obvious difference was found between the experimental groups, mental activities and behavior without exception. 5. The results of OFT and Morris showed that, compared with the control group, there was no significant difference in horizontal movement, vertical movement and space exploration in different groups. 6. Observed the HE staining slice under the light microscopy, organizational structure was neat and various shapes. there is no abnormal compared with the control groupConclusion: 1. GQDs has a protective role for hematopoietic system of SD male rats, and its mechanism may be related to stimulate hematopoietic cell regulation factor GM-CSF. 2. GQDs has no significant effect on the growth and development of SD male rats, nerve behavior and the damage for brain tissue, which showed that its non-toxic side effects on the nervous system. 3. GQDs has good biological safety in hematopoietic system and nervous system, which can be used as a biological materials widely in medical field.