Application Of Amphiphilic Sodium Alginate Carrier Material In Photoelectrochemical Biosensors

Alginates,which are found mainly in marine brown seaweed and soil bacteria,have been widely used in variety of biomedical applications due to their non-toxicity and good biocompatibility.In this paper,hydrophobic alginate sodium?HMA?was used as a smart carrier to conduct a systematic study on the application in vitro cell experiments,the preparation of photoelectrochemical immunosensors and photoelectrochemical DNA biosensors.1.Doxorubicin?DOX?was used as the hydrophobic drug model and HMA as the carrier material to explore the solubilization of HMA.CLSM and SEM were used to characterize the morphology of DOX-HMA micelles.The stability experiment shows that the blank micelles and DOX-HMA micelles have little change in particle size during one week period and are stable under normal physiological conditions.2.DOX-HMA micelles,which can be stable under normal physiological conditions,have a certain pH/enzyme-triggered release behavior.The release ratio in acidic?pH=4.0,6.0?PBS solution is about 20%,while the drug release ratio in DOX-HMA micelles can reach nearly 80%in the presence of?-L-fucosidase?AFU?under acidicmedium.3.The vitro cell experiments indicate that HMA has good biocompatibility and effective cellular internalization.Compared with Hela cells,DOX-HMA micelles have stronger anti-tumor activity against HepG2 cells which have high levels of AFU.DOX-HMA micelles were cultured with cancer cells for different time periods,and it revealed that DOX-HMA micelles could also release slowly and continuously.4.DOX-HMA micelles were assembled on ITO electrodes coated with Eu-TiO₂,and a PEC immunosensor based on DOX-HMA/Eu-TiO₂ for detecting alpha fetoprotein?AFP?antigen was successfully constructed.Due to the presence of DOX-HMA micelles,the photocurrent of Eu-TiO₂ is enhanced and stabilized,and the-COOH on the micelles chain can conduct coupling reaction with AFP antibody.The PEC immunosensor showed the linear range for AFP antigen concentration from 0.5 pg/mL to 100 ng/mL,and the detection limit of 0.41 pg/mL was obtained.5.CdS quantum dots were generated on the ITO electrode by electrodeposition method,and then ZnPc-HMA micelle,which formed by HMA and ZnPc,was assembled on CdS/ITO electrode.It was found that ZnPc-HMA micelle had enhanced and stabilized the photoelectric signal of CdS/ITO electrode.The T-base-rich ssDNA was immobilized on the ZnPc-HMA/CdS/ITO electrode by using the-COOH on the chain of the ZnPc-HMA micelle.In order to realize the detection of Hg²⁺in the solution,we used the reaction between Hg²⁺and base T to form the T-Hg²⁺-T complex.The linear detection range of the immunosensor for Hg²⁺is 10 pm-1.0?M,and the detection limit is 5.7 pM.