Yi Wan Institute of oceanology, CAS

Sulfate-reducing bacteria E. coli Staphylococcus Aureus Ebola virusBacillus Cereus Although the majority of bacteria are useful or beneficial, a few bacteria can cause infectious diseases. Usually a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals.

Robert Hooke (1635 –1703) Microscope Cell Theory Bacteria In 1665 Hooke published microorganism, a book showing observations made with microscopes, and some original work in biology.

Transistors Virus Proteins Electrode 1 mm 1  m 10  m 100  m 100 nm 10 nm 1 nm Bacteria Atoms Pollen Cells Mirror; 16  Chemistry Physics Next Gen 45nm Mites Blood Cells

 MPN method  enzyme-linked immunosorbent assay  polymerase chain reaction  fluorescence Rapid and simple methods for bacteria detection are key to food safety, prevention of environmental pollution, and human health. Electrochemical biosensor

Leland C. Clark Jr. (1918–2005) GO electrode Clark is considered the "Father of Biosensors", and the modern-day glucose sensor used daily by millions of diabetics is based on his research.

Electrochemical work station Electrochemical cell counter working electrode Fuctional film reference insulator electrode material The impedimetric sensor has been applied to measure changes at electrode interfaces for recognition of biological or chemical targets.

Accurate to identfy bacteria –Specific – different bacteria –Sensitive - detect low number Needs: rapid, cheap, and “low tech”

Owing to its unique advantages, an impedimetric sensor has been applied in a wider range of applications in biological studies, such as in the detection and kinetics study of protein or bacteria cells

An impedimetric immunosensor was fabricated for simple and non-labeled detection of sulfate-reducing bacteria (SRB) by immobilizing using an agglutination assay.

The diameter of the Nyquist diagram that is equal to the charge-transfer resistance (R ct ) increased with increasing bacteria concentration Our lectin-based impedance biosensor can offer a direct, sensitive, and rapid label-less monitoring of the bacterial populations. This technique is a promising alternative to the traditional method for monitoring microbial populations.

A sensitive and selective immunosensor for the nonlabeled detection of bacteria is constructed using a self-polymerised polydopamine film as the immobilisation platform.

The growth of bioinspired polydopamine was monitored via QCM methods to track the variation of the mussel-inspired film. We selected pH= 8.5 to produce mild conditions, which are advantageous for the fabrication of biosensors and immobilisation of other biomolecules.

EIS has been used to monitor the number of bacterial cells on modified electrodes. When bacterial cells were adhered onto the mussel-inspired film, the modified electrode showed increased charge-transfer resistance

A facile, sensitive and reliable impedimetric immunosensor doped with reduced graphene sheets (RGSs) and combined with a controllable electrodeposition technique was developed for the selective detection of marine pathogenic sulphate-reducing bacteria

This technique offers high sensitivity and spatial information with a high resolution.

1. Low-cost, simple, and quick impedimetric immunosensors combined with self assembled monolayer platform, controllable electrodisposition platform, and polydopamine platform were fabricated for SRB detection. 2. Our lectin-and antibody-based impedance biosensor can perform direct and sensitive monitoring of the SRB bacterial populations 3. This technique is a promising alternative to the traditional method of bacteria detection

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