Rapid Detection Methods Of Marine Corrosive Microorganisms Based On Optical Nanomaterials

The detection of corrosive microorganisms is of great significance for studying the microbial corrosion mechanism and timely taking microbial corrosion protection measures.In this work,a phenylboronic acid functionalized silver nanoparticles based colorimetric sensor,a DNAzyme-based fluorescence sensor and a GSH-Au???complex based fluorescence sensor and a three receptors-functionalized carbon dots based fluorescence sensor array have been established for sensitive and rapid detection of marine corrosive microorganisms.Main research work is as follows:?1?A simple,rapid and cost-effective colorimetric bacterial detection strategy based on MPBA-AgNPs has been demonstrated.The as-prepared MPBA-AgNPs would be easily aggregated with the addition of excess MPBA.However,the bacteria cells containing cis-diol groups could absorb MPBA-AgNPs onto their surfaces to keep the MPBA-AgNPs dispersed and anti-aggregated,resulting in the various color changes which could be monitored by the naked eye and UV-vis spectrometer.There was a good linear relationship between the absorbance intensity at 400 nm and SRB concentration from 5.0×10⁶ cfu·mL^-1 to 5.0×10⁷ cfu·mL^-1.And the total detection procedure could be finished within 20 minutes.Though semi-quantitative analysis could be realized by the color change which could be distinguished with the naked eye,smartphone based measuring mean makes it suitable for routine laboratory applications.Moreover,the concept of the MPBA-AgNPs based colorimetric strategy can be expanded to other Gram-negative bacteria including corrosive microorganisms suggesting a universal platform for corrosive microorganisms assay.?2?A novel DNA-templated fluorescent silver nanoclusters based sensing system was developed for pathogenic bacterial detection integrated with DNAzyme as the recognition molecule.In the sensing platform,a MNP-DNAzyme-AChE?MDA?complex was constructed,where magnetic nanoparticles plays the role of a carrier,DNAzyme acts as the recognition molecule and a bridge to linke to the acetylcholinesterase.In the presence of the target bacterial lysate,the MDA-target complex was formed through the reaction between DNAzyme and the target molecules lysed by bacteria.And thereby the DNAzyme substrate could be cleaved into two pieces to release AChE into the solution to catalyze the hydrolysis of ATCh to produce TCh,which could significantly enhance the fluorescence of DNA-AgNCs.The detection method has an ultrasensitive detection limit of 60 cfu·mL^-1 with a broad linear range from 1.0×10² to 1.0×10⁷ cfu·mL^-1,and good specificity to the target bacteria.The total detection procedure could be finished within 2 days.The proposed fluorescence detection method can be expanded to the specific detection of corrosive microorganisms by simply replacing with the DNAzyme specific to the certain corrosive microorganisms.?3?Au???-thiolate complexes exhibit AIE property with the presence of Pb²⁺and its fluorescence could be quenched by S^2-.Herein,for the first time,the S^2-responsive fluorescence turn off phenomenon based on Pb²⁺induced aggregation of AIE-active GSH-Au???complexes was used to develop a fluorescence sensor for detection of SRB,which could generate S^2-through reducing SO₄^2-.The proposed method shows good liner detection ranges and satisfactory selectivity.Given the simplicity and timesaving of the proposed fluorescence platform,we expect it could be used for the rapid detection of SRB in the environmental analysis.?4?A novel fluorescent sensor array was designed for identification of bacteria based on three kinds of facile synthesized CDs functionalized with boronic acid,polymixin and vancomycin.The CDs displayed different binding abilities to bacteria due to the variety of physicochemical nature of different bacteria surfaces.The generated fluorescence pattern allowed for the good discrimination of the six kinds of bacteria.The proposed sensor array also show satisfactory discrimination ability in bacteria mixture and real samples.Thus,our proposed sensor array provides a new strategy for simple,rapid,and effective identification of bacteria including SRB and P.aeruginosa.