To develop electrochemical sensors based on hybrid nanostructures of carbonaceous (rGO), metal nanoparticles (i.e, AunPs) and/or conducting polymers (i.e., PEDOT) for tracing pharmaceutical residues in water (i.e., paracetamol, diclofenac).

We have demonstrated the electrochemical preparation of highly stable and uniform rGO-PEDOT:PSS/AuNPs film with high electron transfer rate for further application in detection of acetaminophene. The electrochemical reduction of graphene oxide suspension containing hydrophilic PEDOT:PSS results in a highly uniform and compact matrix which is firmly adhered to electrode surface. Gold nanoparticles were then decorated distinctly at high density on top of that matrix to provide electrocatalytic centers. The results on morphological characterization have demonstrated the uniformity of developed hybrid structures. It was found that the electron transfer rate was much enhanced (apparent transfer rate constant kapp was increased by 2640 times) on highly uniform AuNPs/rGO-PEDOT:PSS hybrid film. The as-prepared hybrid film was employed as transducing platform for electrochemical detection of acetaminophene at low concentrations (1-9 µM) and the detection limit was found to be as low as 532 nM.

The Czech partner conducted the first steps towards synthesis of positively coated silver nanoparticles (using a thiocholine iodine as a modifying agent), which is an important prerequisite for close nanoparticle-diclofenac interaction and therefore sensitive SERS response. Additionally, the Czech partner proved the workability of chosen experimental conditions for the separation of diclofenac from spiked tap water via capillary electrophoresis (CE) with UV detection. Currently, the device, which would allow coupling of CE with SERS, is being designed.

The exchange research activities between research group on Biosensors at USTH and research group on Analytical Chemistry at IAC have been implemented within framework of this research project. The fund has supported two Bachelor students (01 in Czech and 01 in Vietnam) during their trainings.

A facile method to prepare hybrid nanostructure based on carbonaceous materials, metal nanoparticles, and conducting polymers in aqueous conditions using electrochemical approachs. A novel electrochemical sensor based on rGO-PEDOT:PSS/AuNPs for dection of acetaminophene with detection limit of 532 nM.

- Publications:
[1] Vu Cam Nhung, Dau Thi Ngoc Nga, Pham Do Chung, Nguyen Thi Thanh Ngan, Vu Cam Tu, Vu Thi Thu, Facile preparation of uniform and stable AuNPs/rGO-PEDOT: PSS hybrid film for electrochemical detection of pharmaceutical residue in water, Journal of Nanoparticles Research, 24, Article number 34 (2021).
- Training result: 01 Bachelor student (Decision included)

We acknowledge your supports for our exchange scientific activities with our partners at Czech Academy of Science.
In 2022-2023, we will continue our collaboration on the following issues:
-    Loratadine electrochemical sensors
-    SERS sensors based on silver nanoparticles
-    Coupling CE microchip with as-developed sensors.