Synthesis Of Silver Nanoclusters-based Nanocomposites And Investigation Of Biosensing Performances

In this work,silver nanoclusters?AgNCs@Apt?were firstly synthesized using aptamer strands as templates.Then,carbon-based nanomaterials and zirconium-based metal–organic framework,such as 3D reduced graphene oxide?3D-rGO?,graphene quantum dot?GQD?,and Zr-MOF?UiO-66?,were chosen as supporting material to prepare a series of AgNCs-based nanocomposites(AgNCs@Apt@3D-rGO,AgNCs@Apt@GQD,and AgNCs@Apt _CEA@UiO-66).The as-obtained AgNCs-based nanocomposites were employed as the sensitive layers of electrochemical biosensors to detect tumor markers,and also applied for targeted drug delivery.?1?AgNCs@Apt,AgNCs@Apt@3D-rGO and AgNCs@Apt@GQD nanocomposites were prepared by room temperature stirring and used as the sensitive layers to fabricate electrochemical aptasensors for detection of platelet-derived growth factor-BB.The developed AgNCs@Apt@3D-rGO-based aptasensor exhibited the highest sensitivity for PDGF-BB detection among the three kinds of fabricated aptasensors,with an extremely low detection limit?LOD?of 0.82 pg·mL^-1.In addition,the AgNCs@Apt@3D-rGO-based aptasensor showed high selectivity,regenerability,and applicability in real serum sample.?2?AgNCs@Apt_CEA@UiO-66 nanocomposites were also synthesized by room temperature stirring and used as the sensitive layers to fabricate both electrochemical and surface plasmon resonance spectroscopy?SPR?aptasensors for detection of trace carcinoembryonic antigen.The proposed electrochemical aptasensor exhibited high sensitivity with a LOD of 4.93 pg·m L^-1,and the developed SPR biosensor exhibited a slightly high LOD of 0.3 ng·mL^-1.The aptasensor also displayed high selectivity,good reproducibility,stability,acceptable regenerability,and applicability in real serum sample.?3?Furthermore,AgNCs@Apt _AS1411@UiO-66@DOX was synthesized using AS1411aptamer strands as template and encapsulating doxorubicin?DOX?by one-step method.The as-prepared nanocomposite targetedly delivered DOX to the nucleus of tumor cells,and therefore exhibited excellent selective growth inhibition for tumor cells.Our work enriched the research method of preparation of AgNCs@Apt-based nanocomposites and construction of aptasensors,and also proceeded a preliminary exploration in targeted drug delivery.This work broadens the way of thinking to apply the AgNCs@Apt-based nanocomposites in biomedical and clinical diagnosis.