The Effect Of Biofilm Culture Conditions On The Fluorescence Properties Of Biofilm Based Carbonized Polymer Dots

Carbon dots are the generic name for several carbon nanomaterials,usually defined as small carbon nanoparticles with dimensions less than 10 nm.Compared with other carbon nanomaterials,carbon dots have special luminescence characteristics,that is the luminescence is excitation-dependent.Since carbon dots do not contain heavy metal elements,they do not have the high toxicity of inorganic semiconductor quantum dots.Therefore,it has potential applications in bioimaging,ion detection,biosensing and photocatalysis.At the same time,as an environmentally friendly fluorescent nanomaterial,the green method for synthesizing fluorescent polymerized carbon dots is also one of the main contents of carbon dots research.The advantages of synthesizing such polymerized carbon dots are that their materials are cheap and renewable,suitable for large-scale preparation,reduce the contact with chemical substances,and have little environmental impact.In this study,a green method for synthesizing fluorescent carbon dots was established.Using natural water biofilm and Chlorella as the only material,biofilm based polymerized carbon dots were prepared by hydrothermal method.The Chlorella based polymerized carbon dots prepared by this method can achieve ideal size and uniformity.It also can be dispersed in aqueous solvent well,and a bright blue fluorescence of solution can be observed.In the optical excitation experiment,the maximum fluorescence emission of 420 nm under the excitation of 330 nm light.And the biofilm based polymerized carbon dots have similar properties,the maximum fluorescence emission of 420 nm under the excitation of 310 nm light.The synthesizing method can be used for the preparation of carbonized polymer dots from natural biofilm materials in different environment conditions,and the prepared products have stable properties.The obtained fluorescent carbon dots can be used for detecting trace amounts of vitamin B12 in water,and quantitative analysis of vitamin B12 can be performed by measuring the fluorescence intensity of the sample at 310 nm.The method possesses high sensitivity in the concentration range of 9×10^-3-2.67?M,and the lower detection limit(LOD)is about 9.00 n M.