Source: UNIVERSITY OF MISSOURI submitted to
SEPARATION AND DETECTION OF CHEMICAL AND BIOLOGICAL CONTAMINANTS IN FRESH PRODUCE BY A SERS-BASED SENSING PLATFORM
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
1015418
Grant No.
2018-67017-27880
Project No.
MO00060024
Proposal No.
2017-08050
Multistate No.
(N/A)
Program Code
A1331
Project Start Date
Mar 1, 2018
Project End Date
Mar 25, 2022
Grant Year
2018
Project Director
Lin, M.
Recipient Organization
UNIVERSITY OF MISSOURI
(N/A)
COLUMBIA,MO 65211
Performing Department
Office of Sponsored Programs
Non Technical Summary
Fresh produce has been increasingly associated with chemical and biological contaminants such as pesticides and foodborne pathogens. Early and rapid detection of contaminants in produce is an important step in ensuring food safety. However, separation and simultaneous detection of both chemical and biological contaminants present a significant analytical challenge. The overall objectives are to develop and validate novel separation and extraction methods for the efficient capture of foodborne contaminants from fresh produce and develop a surface-enhanced Raman spectroscopy (SERS) platform for rapid detection of contaminants in samples. Having suitable and sensitive techniques is critical for rapid detection of contaminants in fresh produce products. The results from this project are important to maintain the safety and sustainability of agriculture and food systems.
Animal Health Component
0%
Research Effort Categories
Basic
70%
Applied
30%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
71114992000100%
Goals / Objectives
The overall objectives of this multi-disciplinary project are to develop and validate novel separation and extraction methods for the efficient capture of foodborne contaminants from fresh produce and develop a surface-enhanced Raman spectroscopy (SERS) platform for rapid detection and quantification of both chemical and biological contaminants in samples. Two approaches for isolation and separation of chemical and biological contaminants will be developed: a rapid and direct "wipe-and-extract" method based on hybrid nanocellulose films coupled with SERS for screening samples; and a novel separation/detection method using plasmofluidic devices integrated with micro electrophoresis, which will be coupled with SERS for confirmatory analysis of samples. This novel methodology can be used for simultaneous isolation and detection of both chemical and biological contaminants in fresh produce and hasn't been reported before. Specific objectives of this project are to: (1) synthesize hybrid nanocellulose films impregnated with gold or silver nanoparticles; (2) evaluate a rapid and direct method based on "wipe-and-test" process using the hybrid nanocellulose films for rapid extraction of the analyte molecules coupled with SERS analysis; (3) fabricate plasmofluidic devices integrated with micro electrophoresis to extract, isolate, and separate analytes (pesticides, bacterial cells, etc) from complex matrices; (4) evaluate a novel and integrated separation/detection method using plasmofluidic devices coupled with SERS for detection and quantification of analyte molecules; (5) establish a protocol for rapid detection of chemical and biological contaminants in real fresh produce samples (fruits and vegetables).
Project Methods
The methods used in this project include: (1) synthesize hybrid nanocellulose films impregnated with gold or silver nanoparticles; (2) evaluate a rapid and direct method based on "wipe-and-test" process using the hybrid nanocellulose films for rapid extraction of the analyte molecules coupled with SERS analysis; (3) fabricate plasmofluidic devices integrated with micro electrophoresis to extract, isolate, and separate analytes (pesticides, bacterial cells, etc) from complex matrices; (4) evaluate a novel and integrated separation/detection method using plasmofluidic devices coupled with SERS for detection and quantification of analyte molecules; (5) establish a protocol for rapid detection of chemical and biological contaminants in real fresh produce samples (fruits and vegetables).

Progress 03/01/18 to 03/25/22

Outputs
Target Audience:Audiences were food scientists, students, professionals from academia, the food industry, and government agencies.? Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training for four doctoral students and four master's students. How have the results been disseminated to communities of interest?The results of this project have been disseminated in peer-reviewed journals with high impact factors and at the professional conferences, including IFT, ACS, IAFP conference. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This project successfullydevelopednanocomposites based on nanofibrillar cellulose (NFC) coated with gold-silver (core-shell) nanoparticles (Au@Ag NPs) as novelsurface-enhanced Raman spectroscopy (SERS)substrates. Characteristic peaks were clearly observable in all SERS spectra even at a low concentration of 10 µg/L of pesticides. Limit of detection values of 71 and 46 µg/L were obtained for thiram and paraquat.We also developed SERS method coupled with cellulose nanofiber (CNF)-based wipers that were fabricated on quartz papers coated with a mixture of silver nanoparticle (AgNP) and gold nanostar (AuNS). A "drop-wipe-test" protocol was developed for rapid detection of pesticide residues in vegetables by SERS. Tremendously enhanced Raman scattering signals were obtained from the quartz/CNF/mixture (AgNP+AuNS) substrate, which was much higher than the paper/mixture (AgNP+AuNS) substrate. This method was used to detect ferbam on kale leaves within a few minutes and the detection limit was 50mg/kg based on the PLS models (R2= 0.89).The enhancement factor of the SERS substrate was calculated to be ~104with satisfactory reproducibility.Satisfactory SERS performance could be achieved within 1-month storage period. These results demonstrate that this CNF-based SERS/wiper method is a practical approach for rapid detection of chemical contaminants in fresh produce. We also successfully developedSERS optofluidic sensors coupled with immunoprobes to simultaneously separate and detect multiple dangerous foodborne pathogens,Escherichia coliO157:H7,Salmonella Enteritidis,andSalmonella TyphimuriumDT104 in lettuce and packed salad. The method consists of three steps of (i) enrichment to ensure that even a single cell can be detected in the food sample, (ii) selective separation and labelling of target bacteria by their specific antibody-bearing SERS-nanotags and (iii) detection of tagged bacterial cells using SERS within a hydrodynamic flow-focusing SERS optofluidic device, where even low counts of bacterial cells were detectable in the very thin-film-like sample stream. SERS-nanotags consisted of different Raman reporter molecules, representing each species, i.e., the detection of Raman reporter confirms the presence of the target pathogen. The anti-E. coliantibody used in this study functions against all strains ofE. coliO157:H7 and the anti-Salmonellaantibody used in this work acts on bothS. Enteritidis,andS. TyphimuriumDT104. Bacterial counts of 1000, 100, and 10 CFU/mL were successfully detected after only 15 min enrichment. Our method showed a very low detection limit value of 10 CFU/mL for the bacterial mixture in both lettuce and packed salad, proving the efficiency and high sensitivity of our method to detect multiple pathogens in the food samples. The total analysis time, including sample preparation for simultaneous detection of multiple bacteria, was estimated to be 2 h, which is remarkably less than the days required in conventional methods. Hence, our proposed protocol is considered a promising rapid and efficient approach for routinepathogenscreeningof food samples. In addition, theSERS-based microfluidic immunosensor was developed to separate and detect E. coliO157:H7in romaine lettuce. SERS-nanoprobes, containing gold nanoparticles and specific antibodies againstE. coliO157:H7, were used to selectively anchor onto theE. coliO157:H7 cells and separate them from lettuce samples. Separated cells within a hydrodynamic flow-focusing microfluidic device were then detected using the Raman spectroscopewith an excitation laser of 785 nm at∼35 mW. Bacterial concentrations of 100, 10, 1, and 0.5 CFU/mL were successfully detected after less than 60 min of enrichment. The limit of detection ofE. coliO157:H7 in romaine lettuce was found to be 0.5 CFU/mL, verifying the sensitivity of our protocol for detection of pathogens in food samples. High linearity (R2> 0.93) in the calibration curves forE. coliO157:H7 was observed after 30 min of enrichment. The method reduced the analysis time for single-cell detection to only 1 h, which is significantly shorter than the days required in conventional methods. Combining the hydrodynamic flow-focusing microfluidic device with SERS-nanoprobes provides a reliable, selective, and sensitive approach for the detectionof various pathogens in complex food samples. We also developed an in-field analytical technique for food samples by integrating filtration into a SERS microchip. This microchip embedded a filter membrane in the chip inlet to eliminate interfering particulates and enrich target analytes. The design and geometry of the channel were optimized by finite elemental method (FEM) to tailor the fluctuations of flow velocity (within 0-24 μL/s) and facilitate efficient mixing of the filtrate with nanoparticles in two steps. Four pesticides (thiabendazole, thiram, endosulfan, and malathion) were successfully detected either individually or as a mixture in strawberries using this sensor. Strong Raman signals were obtained for the four studied pesticidesand their major peaks were clearly observable even at a low concentration of 5 µg/kg. Limit of detections of four pesticides in strawberry extract were in the range of 44 - 88 μg/kg, showing good sensitivityof the sensor to the target analytes. High selectivity of the sensor was also proved by successful detection of each individual pesticide as a mixture in strawberry matrices. High recoveries (90-122%) were achieved for the four pesticides in strawberry extract. This sensor is the first filter-based SERS microchip for identification and quantification of multiple target analytes in complex food samples. In summary,this project successfully developed and validated novel separation and extraction methods for the efficient capture of foodborne contaminants from fresh produce and develop SERS platforms for rapid detection of contaminants in samples.Objectives have been achievedto synthesize hybrid nanocellulose films impregnated with metal nanoparticles, evaluated a rapid and direct method based on "wipe-and-test" method using the nanocellulose films for rapid extraction of the analyte molecules coupled with SERS analysis, synthesized plasmofluidic devices integrated with micro electrophoresis for separation and isolation of analytes from complex matrices, and coupled them with SERS for detection and quantification of the analyte molecules, and established protocols for rapid detection of chemical and biological contaminants in real fresh produce samples. More manuscripts are in preparation and more high-quality publications are expected in the next one or two years.

Publications

  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Asgari, S., Dhital, R., Ali Aghvami, S., Mustapha, A., Zhang, Y., Lin, M. 2022. Separation and detection of E. coli O157:H7 using a SERS-based microfluidic immunosensor. Microchimica Acta. 189, 111.
  • Type: Journal Articles Status: Submitted Year Published: 2022 Citation: Asgari, S., Dhital, R., Mustapha, M., Lin, M. 2022. Multiplex detection of foodborne pathogens using a SERS optofluidic sensor coupled with immunoassay. International Journal of Food Microbiology. Submitted.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Asgari, S., Wu, G., Ali Aghvami, S., Zhang, Y., Lin, M. 2021. Optimisation using the finite element method of a filter-based microfluidic SERS sensor for detection of multiple pesticides in strawberry. Food Addit. Contam. Part A. 38(4), 646-658.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Sun L., Yu, Z., Alsammarraie, F.K., Lin, M.-H., Kong, F., Huang, M., Lin, M. 2021. Development of cellulose nanofiber-based substrates for rapid detection of ferbam in kale by surface-enhanced Raman spectroscopy. Food Chem. 347, 129023.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Lin, M.-H., Sun, L., Kong, F., Lin, M. 2021. Rapid detection of paraquat residues in green tea using surface-enhanced Raman spectroscopy (SERS) coupled with gold nanostars. Food Control. 130, 108280.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Zhang, C.; Li, D.; Xie, Y.; Stalla, D.; Hua, P.; Nguyen, D. T.; Xin, M.; Lin, J. 2021. Machine learning assisted rediscovery of methane storage and separation in porous carbon from material literature. Fuel, 290, 120080.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Asgari, S., Sun L., Lin, J., Wu, G., Zhang, Y., Lin, M. 2020. Nanofibrillar cellulose/Au@Ag nanoparticle nanocomposite as an efficient SERS substrate. Microchimica Acta. 187, 390.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Yu, Z., Wang, W., Sun, L., Kong, F., Lin, M., Mustapha, M. 2020. Preparation of cellulose nanofibril/titanium dioxide nanoparticle nanocomposites as fillers for PVA-based packaging and investigation into their intestinal toxicity. International Journal of Biological Macromolecules. 156, 1174-1182.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wang, W., Yu, Z., Alsammarraie, F.K., Kong, F., Lin, M., Mustapha, A. 2020. Properties and antimicrobial activity of polyvinyl alcohol-modified bacterial nanocellulose packaging films incorporated with silver nanoparticle. Food Hydrocolloids. 100, 105411.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Y. Xie, C. Zhang, X. Hu, C. Zhang, S. P. Kelley, J. L. Atwood, J. Lin. 2020. Machine learning assisted synthesis of metal-organic nanocapsules. Journal of the American Chemical Society, 142 (3), 1475-1481.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Asgari, S., Saberi, A.H., McClements, D.J., Lin, M. 2019. Microemulsions as nanoreactors for synthesis of biopolymer nanoparticles. Trends in Food Science & Technology, 86, 118-130.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Sun, L., Yu, Z., Lin, M. 2019. Synthesis of polyhedral gold nanostars as surface-enhanced Raman spectroscopy substrates for measurement of thiram in peach juice. Analyst, 144, 4820-4825.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Yu, Z., Dhital, R., Wang, W., Sun, L., Zeng, W., Mustapha, A., Lin, M. 2019. Development of multifunctional nanocomposites containing cellulose nanofibrils and soy proteins as food packaging material. Food Packaging and Shelf Life, 21, 100366.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Asgari, S., Lin, M. Separation and detection of chemical and biological contaminants in fresh produce by plasmofluidic device. The 37th Annual Research & Creative Activities Forum (RCAF), University of Missouri, Graduate Professional Council (GPC), November 13 - 14, 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Alsammarraie, F., Lin, M., Mustapha, A. Rapid determination of thiabendazole in juice by SERS coupled with novel gold nano-substrates. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Sun, L., Yu, Z., Lin, M. Synthesis of polyhedral gold nanostars as surface-enhanced Raman spectroscopy (SERS) Substrates for Rapid Detection of Thiram in Peach Juice. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Deng, H., Xu, X., Zhang, C., Su, J.-W., Huang, G., Lin, J. 2020. Deterministic self-morphing of soft-stiff hybridized polymeric films for acoustic metamaterials. ACS Applied Materials & Interfaces 12, 13378-13385.


Progress 03/01/21 to 02/28/22

Outputs
Target Audience:Audiences were food scientists, students, professionals from academia, the food industry, and government agencies.? Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training for two doctoral students and two Master's students. How have the results been disseminated to communities of interest?The results of this project have been disseminated in peer-reviewed journals andat the professional conferences, includingIFT conference. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we willdevelop a SERS optofluidic sensor coupled with an immunoassay to simultaneously detect multiple dangerous foodborne pathogens,E. coliO157:H7,Salmonella Enteritidis,andSalmonella TyphimuriumDT104 in a flow-focusing hydrodynamic microfluidic chip. The detection will be performed in the two commonly implicated vehicles for these pathogens: lettuce and a packed salad. In this protocol, a complex of multiple specific SERS-nanotags will be used to simultaneously probe and detect multiple targets in the same sample. Hypothetically, adding an enrichment step prior to the detection and using flow-focusing hydrodynamic microfluidic chip results in a very low LOD value for both bacteria. The new method will be used for the detection of multiple foodborne pathogens using SERS optofluidic sensor coupled with immunoassay using a flow-focusing hydrodynamic microfluidic chip.

Impacts
What was accomplished under these goals? During the reporting period, experiments were conducted to develop an in-field analytical technique by integrating filtration into a surface-enhanced Raman spectroscopy (SERS) microchip for measuring food samples. The sensor contains two main channels, between which a filter membrane has been bonded at the inlet site. A filter membrane was embedded in the microchip at the inlet to filter out interfering particulates and enrich target compounds. Food sample is filtered out from the unwanted parts while flowing from the upper to the lower channel. The filtrate is then mixed with nanoparticle colloid solution and analyzed by SERS in the detection zone while moving through the lower channel. The design and geometry of the channel were optimized by finite elemental method (FEM) to tailor the fluctuations of flow velocity (within 0-24 μL/s) and facilitate efficient mixing of the filtrate with nanoparticles in two steps. Selected pesticides were successfully detected either individually or as a mixture in strawberries using this sensor. Strong Raman signals were obtained for the four studied pesticides and their major peaks were observable as low as 5 µg/Kg. The limit of detections of four pesticides in the strawberry extract were in the range of 44 - 88 μg/Kg, indicating a good sensitivity of the sensor to the target analytes. The high selectivity of the sensor was also proved by the successful detection of each pesticide as a mixture in strawberry matrices. High recoveries (90-122%) were achieved for the four pesticides in the strawberry extract. This sensor is the first filter-based SERS microchip for the identification and quantification of multiple target analytes in complex food samples. In addition, we developed a novel SERS method coupled with cellulose nanofiber (CNF)-based SERS wipers that were fabricated on quartz papers coated with a mixture of silver nanoparticle (AgNP) and gold nanostar (AuNS). A "drop-wipe-test" protocol was developed for rapid detection of pesticide residues in vegetables by SERS. Tremendously enhanced Raman scattering signals were obtained from the quartz/CNF/mixture (AgNP+AuNS) substrate, which was much higher than the paper/mixture (AgNP+AuNS) substrate. This method was used to detect ferbam on kale leaves within a few minutes and the detection limit was 50mg/kg based on the PLS models (R2= 0.89).The enhancement factor of the SERS substrate was calculated to be ~104with satisfactory reproducibility.Satisfactory SERS performance could be achieved within 1-month storage period. These results demonstrate that this CNF-based SERS/wiper method is a practical approach for rapid detection of chemical contaminants in fresh produce.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Y. Xie, C. Zhang, X. Hu, C. Zhang, S. P. Kelley, J. L. Atwood, J. Lin. 2020. Machine learning assisted synthesis of metal-organic nanocapsules. Journal of the American Chemical Society, 142 (3), 1475-1481.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Asgari, S., Wu, G., Ali Aghvami, S., Zhang, Y., Lin, M. 2021. Optimisation using the finite element method of a filter-based microfluidic SERS sensor for detection of multiple pesticides in strawberry. Food Addit. Contam. Part A. 38(4), 646-658.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Sun L., Yu, Z., Alsammarraie, F.K., Lin, M.-H., Kong, F., Huang, M., Lin, M. 2021. Development of cellulose nanofiber-based substrates for rapid detection of ferbam in kale by surface-enhanced Raman spectroscopy. Food Chem. 347, 129023.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Zhang, C.; Li, D.; Xie, Y.; Stalla, D.; Hua, P.; Nguyen, D. T.; Xin, M.; Lin, J. 2021. Machine learning assisted rediscovery of methane storage and separation in porous carbon from material literature. Fuel, 290, 120080.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Asgari, S., Sun L., Lin, J., Wu, G., Zhang, Y., Lin, M. 2020. Nanofibrillar cellulose/Au@Ag nanoparticle nanocomposite as an efficient SERS substrate. Microchimica Acta. 187, 390.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Deng, H., Xu, X., Zhang, C., Su, J.-W., Huang, G., Lin, J. 2020. Deterministic self-morphing of soft-stiff hybridized polymeric films for acoustic metamaterials. ACS Applied Materials & Interfaces 12, 13378-13385.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Yu, Z., Wang, W., Sun, L., Kong, F., Lin, M., Mustapha, M. 2020. Preparation of cellulose nanofibril/titanium dioxide nanoparticle nanocomposites as fillers for PVA-based packaging and investigation into their intestinal toxicity. International Journal of Biological Macromolecules. 156, 1174-1182.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wang, W., Yu, Z., Alsammarraie, F.K., Kong, F., Lin, M., Mustapha, A. 2020. Properties and antimicrobial activity of polyvinyl alcohol-modified bacterial nanocellulose packaging films incorporated with silver nanoparticle. Food Hydrocolloids. 100, 105411.


Progress 03/01/20 to 02/28/21

Outputs
Target Audience:Audiences were food scientists, students, professionals from academia, the food industry, and government agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training for two doctoral students and two Master's students. How have the results been disseminated to communities of interest?The results of this project have been disseminated in peer-reviewed journals, at the professional conferences including 37th Annual Research & Creative Activities Forum (RCAF) of Mizzou and IFT conference. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we will continue to work on the preparation of the sample in microfluidic-based analysis protocols. We will develop an in-field analytical technique for food samples by integrating filtration into a SERSmicrochip. Filter-based SERS microchip overcomes the limitation of food microfluidics for sample preparation by embedding a filter membrane in the chip inlet, which eliminates interfering particulates in the sample, so that the target analytes are enriched in the filtrate and results in a more sensitive and selective detection.

Impacts
What was accomplished under these goals? During the reporting period, experiments were carried out to investigate the pesticide residues in fresh produce by developing a novel swab method that utilized nanocellulose-based substrates for surface-enhanced Raman spectroscopy (SERS) applications. Cellulose nanofiber (CNF)-based SERS wipers were fabricated on quartz papers coated with a mixture of silver nanoparticle (AgNP) and gold nanostar (AuNS). A "drop-wipe-test" protocol was developed for rapid detection of pesticide residues in vegetables by SERS. A Raman-active reporter, 4-aminothiophenol, was used to evaluate the performance and sensitivity of the wiper/SERS method. Chloroauric acid and sodium citrate solution were used to synthesize AuNS.NaBH4solution and AgNO3were used to synthesize AgNP solution that was tested by UV spectroscopy. CationicCNF was synthesized using (2,3-epoxypropl) trimethylammonium chloride (EPTMAC).The CNF/mixture (AgNP+AuNS) wiper was prepared. An aliquot (1 mL) of the modified CNF was washed three times to remove chemical residues at 10,000 rpm for 10 min. After washing, the solution was concentrated two times prior to the next synthesis. A volume of 300mL of AgNP and AuNS with a ratio of 2:1 was mixed as the nanoparticle solution (the mixture). Then, the modified CNF and nanoparticle solution with a ratio of 1:1 was mixed well. A volume of 4mL of CNF/mixture was dropped on a 1 cm´1 cm quartz paper, followed by heat drying at 55oC. TEM images were acquired by characterizing AgNP, AuNS, CNF, and the mixture using a JEOL electron microscope operated at an accelerating voltage of 120 kV. The synthesized wiper was stored in a vacuum-sealed bag. Different concentrations of ferbam in acetone solutions were prepared. Kale leaves were thoroughly cleaned before the experiment to ensure that there were no other residues on the leaves. Leaves without the treatment of pesticide were used as the control samples. Kale leaves (2 cm´2 cm) were soaked in different concentrations of ferbam solution for 12 h. The samples were then air-dried at room temperature. An aliquot (10mL) of acetone was dropped on the leaf surface. Then, an as-prepared wiper was used to swab it and dried on a heat plate at 40oC. A DXR2 Raman spectroscopy with a 785-nm laser source was used in this experiment. Each wiper sample was measured at different 10 locations and averaged spectra were obtained. The results show that the intensity of SERS scattering signals obtained from the quartz/CNF/mixture (AgNP+AuNS) substrate was much higher than the paper/mixture (AgNP+AuNS) substrate. A stability test was conducted under vacuum packaging, demonstrating that satisfactory SERS performance could be achieved within 1-month storage period. This method was used to detect ferbam on kale leaves and the detection limit was 50mg/kg. The testing process for a sample can be finished within a few minutes. These results demonstrate that this CNF-based SERS/wiper method is a practical approach for rapid detection of chemical contaminants in fresh produce. In addition, experiments were carried out to develop an in-field analytical technique for food samples by integrating filtration into a SERS microchip. Filter-based SERS microchip overcomes the limitation of food microfluidics for sample preparation by embedding a filter membrane in the chip inlet, which eliminates interfering particulates in the sample, so that the target analytes are enriched in the filtrate and results in a more sensitive and selective detection. The design and geometry of the channel were also optimized by finite elemental method to tailor the fluctuations of flow velocity (within a range of 0-24 μL/s), facilitate efficient mixing of the filtrate with SERS-active nanoparticles in two steps, and to maintain detection in a more stable condition. Four pesticides (thiabendazole, thiram, endosulfan, and malathion) were successfully detected either individually or as a mixture in strawberries using this sensor. Strong Raman signals were obtained for the four studied pesticides and their major peaks were clearly observable even at a low concentration of 5µg/L. Limit of detections of thiabendazole, thiram, endosulfan and malathion in strawberry extract were 43-87 μg/L, respectively, validating remarkable sensitivity of the sensor to the target analytes. High selectivity of the sensor was also proved by successful detection of each individual pesticide as a mixture in strawberry matrices. High recoveries were achieved for the four pesticides in strawberry extract. Our proposed sensor offers a flexible identification and quantification approach for multiple target analytes in complex food samples and is promising for commercialization.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Asgari, S., Sun L., Lin, J., Wu, G., Zhang, Y., Lin, M. 2020. Nanofibrillar cellulose/Au@Ag nanoparticle nanocomposite as an efficient SERS substrate. Microchimica Acta. 187, 390.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Deng, H., Xu, X., Zhang, C., Su, J.-W., Huang, G., Lin, J. 2020. Deterministic self-morphing of soft-stiff hybridized polymeric films for acoustic metamaterials. ACS Applied Materials & Interfaces 12, 13378-13385.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Yu, Z., Wang, W., Sun, L., Kong, F., Lin, M., Mustapha, M. 2020. Preparation of cellulose nanofibril/titanium dioxide nanoparticle nanocomposites as fillers for PVA-based packaging and investigation into their intestinal toxicity. International Journal of Biological Macromolecules. 156, 1174-1182.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wang, W., Yu, Z., Alsammarraie, F.K., Kong, F., Lin, M., Mustapha, A. 2020. Properties and antimicrobial activity of polyvinyl alcohol-modified bacterial nanocellulose packaging films incorporated with silver nanoparticle. Food Hydrocolloids. 100, 105411.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Y. Xie, C. Zhang, X. Hu, C. Zhang, S. P. Kelley, J. L. Atwood, J. Lin. 2020. Machine learning assisted synthesis of metal-organic nanocapsules. Journal of the American Chemical Society, 142 (3), 1475-1481.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Asgari, S., Saberi, A.H., McClements, D.J., Lin, M. 2019. Microemulsions as nanoreactors for synthesis of biopolymer nanoparticles. Trends in Food Science & Technology, 86, 118-130.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Sun, L., Yu, Z., Lin, M. 2019. Synthesis of polyhedral gold nanostars as surface-enhanced Raman spectroscopy substrates for measurement of thiram in peach juice. Analyst, 144, 4820-4825.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Yu, Z., Dhital, R., Wang, W., Sun, L., Zeng, W., Mustapha, A., Lin, M. 2019. Development of multifunctional nanocomposites containing cellulose nanofibrils and soy proteins as food packaging material. Food Packaging and Shelf Life, 21, 100366.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Yu, Z., Wang, W., Kong, F., Lin, M., Mustapha, A. 2019. Cellulose nanofibril/silver nanoparticle composite as an active food packaging system and its toxicity to human colon cells. International Journal of Biological Macromolecules. 129, 887-894.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Yu, Z., Wang, W., Dhital, R., Kong, F., Mustapha, M., Lin, M. 2019. Antimicrobial effect and toxicity of cellulose nanofibril/silver nanoparticle nanocomposite prepared by an ultraviolet irradiation method. Colloids Surf. B. 180, 212-220.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Asgari, S., Lin, M. Separation and Detection of Chemical and Biological Contaminants in Fresh Produce by Plasmofluidic Device. 37th Annual Research & Creative Activities Forum (RCAF), Health Sciences, Medicine, and Veterinary Medicine category, University of Missouri, Graduate Professional Council (GPC), November 13 - 14, 2020.


Progress 03/01/19 to 02/29/20

Outputs
Target Audience:Audiences were food scientists, students, professionals from academia, the food industry, and government agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training for three doctoral students and two Master's students. How have the results been disseminated to communities of interest?The results of this project have been disseminated in peer-reviewed journals, at the professional conferences including IFT conference in 2019. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we will continue to develop and validate separation and extraction methods for efficient capture of foodborne contaminants from fresh produce and develop a SERS platform for rapid detection and quantification of both chemical and biological contaminants in samples. We will develop hybrid nanocellulose films coupled with SERS for screening samples; and a novel separation/detection method using plasmofluidic devices integrated with micro electrophoresis. However, some methods will cause a problem known as memory effect that is the attachment of analytes and NPs on the microfluidic inner wall, which may interfere with the detection procedure. To solve this issue, possible solutions will be evaluated, such as: (1) prepare a strong washing solution to wash off the stuck analytes and NPs from the inner wall in a specific time interval; (2) use mineral oil to cover the inner wall to avoid the direct attachment of NPs to the wall.

Impacts
What was accomplished under these goals? During the reporting period, experiments were carried out to develop efficient SERS substrate and practical microfluidic platform for the sensor. In the beginning of the project, we fabricated a novel SERS substrate, Au@Ag core-shell nanoparticles (Au@Ag NPs) that have a gold core and silver coating. In this study, a new approach was taken to modify this SERS substrate to have more efficient, reproducible, and uniform SERS substrate based on a nanocomposite using nanoparticles (NPs). Specific objectives were to:(1)fabricate a stable, efficient SERS substrate based on nanofibrillar cellulose/Au@Ag NPs (NFC/Au@Ag NP) nanocomposite; (2)apply this SERS substrate for detection of multiple pesticides in lettuce as a model for fresh produce; (3) design and fabricate microfluidic device as an efficient sensor platform. The preparation of Au@Ag NPs was based on a seed-growth procedure. The as prepared NPs were used for the fabrication of SERS nanocomposite. Various combinations of different concentrations of NFC suspension and Au@Ag NPs were used to synthesize and identify the optimum SERS substrate. Nanocomposites were prepared by mixing of NFC suspension and concentrated Au@Ag NP solution with a ratio of 1:1. The mixing time effect was also investigated at 5-min intervals over 30-min mixing. Subsequently, an aliquot of 2 µL of the mixture was dropped on a slide and air-dried at room temperature. The as-prepared nanocomposite was used as the SERS substrate. A Raman reporter, 4-mercaptobenzoic acid (4-MBA), was used to test SERS performance of the nanocomposite. Based on the preliminary tests, the combination of the most concentrated Au@Ag NP solution with 3% NFC solution showed the best SERS performance, so this composite was chosen and used for SERS analysis. SEM and TEM images of NFC/Au@Ag NP nanocompositeclearly show that fibers are entirely covered by individual NPs. Many clustered NPs are also observable on different spots of nanofibers, especially at the junctions, making these regions as potential hotspots. To evaluate SERS performance for detection of pesticides, SERS spectra of different concentrations of thiram and paraquat on NFC/Au@Ag NP nanocomposite were measured and the acquired average SERS spectra were statistically analyzed. NFC/Au@Ag NP nanocomposite showed high SERS performance for detection of these two pesticides with relatively high Raman intensity of ~35000 (for thiram) and ~30000 (for paraquat) and very low limit of detection values of 71 µg/L for thiram and 46 µg/L for paraquat in lettuce samples. Simultaneous detection of thiram and paraquat in lettuce was successfully performed by NFC/Au@Ag NP nanocomposite. All Raman peaks were clear and sharp enough to present fingerprint-like spectra for each pesticide in complex lettuce extract. For the microfluidic platform, new designs were prepared using AutoCad software for fabrication of the photomask. The photomasks were used for fabrication of PDMS microfluidic devices through photolithography process. The new designs have the following characteristics: width of 40 µm, depth of 80 µm, and the length of ~15 mm. All the designs contain a detection zone that is used for exposing the laser and collection of scattered lights by a SERS detector. The designs have some minor differences to evaluate their functionality and effectiveness as a SERS platform. As the first protocol, a mixture of nanoparticles and pesticide solution was injected into the microfluidic device and then exposed the detection zone in microfluidic device by the laser and collected the scattered lights by the SERS detector. Then nest step was focused on the detection of paraquat using the microfluidic-SERS sensor. First, an appropriate ratio was evaluated for mixing of nanoparticle solution with the paraquat solution. Among different ratios tested, 1:1 v/v was found as the best mixing ratio. The mixture was freshly prepared prior to the detection procedure. The inlet of the prepared microfluidic device was connected to a syringe pump to inject the sample in the channel. The nanoparticle-paraquat mixture was injected through the channel with a flow rate of 2 µL/min. A 785-nm laser was used to expose the detection zone and the SERS spectra were collected at a defined time interval. To distinguish the peaks of paraquat from PDMS peaks, methods were conducted to: (1) use a chemical to make NPs clustered to have more SERS hotspots; (2) change the channel design to accumulate NPs more efficiently in the detection zone or to slow them down to have longer exposure time; (3) have an extra stable platform to make NPs and analytes to accumulate at the detection zone for efficient detection.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Sun, L., Yu, Z., Lin, M.* 2019. Synthesis of polyhedral gold nanostars as surface-enhanced Raman spectroscopy substrates for measurement of thiram in peach juice. Analyst, 144, 4820-4825.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Asgari, S., Saberi, A.H., McClements, D.J., Lin, M.* 2019. Microemulsions as nanoreactors for synthesis of biopolymer nanoparticles. Trends in Food Science & Technology, 86, 118-130.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Alsammarraie, F., Lin, M., Mustapha, A. Rapid Determination of Thiabendazole in Juice by SERS coupled with Novel Gold Nano-substrates. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Yu, Z., Lin, M., Mustapha, A. Synthesis of Cellulose Nanofibril/Titanium Dioxide Nanoparticle Composites and Investigation Into Their Toxicity. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Yu, Z., Lin, M., Mustapha, A. Antimicrobial Effect and Toxicity of Cellulose Nanofibril/Silver Nanoparticle Nanocomposite Prepared by the Ultraviolet Irradiation Method. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Sun, L., Yu, Z., Lin, M. Synthesis of Polyhedral Gold Nanostars as Surface-enhanced Raman Spectroscopy (SERS) Substrates for Rapid Detection of Thiram in Peach Juice. 2019 IFT Annual Meeting. June 2-5, New Orleans, LA.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Yu, Z., Dhital, R., Wang, W., Sun, L., Zeng, W., Mustapha, A.*, Lin, M.* 2019. Development of multifunctional nanocomposites containing cellulose nanofibrils and soy proteins as food packaging material. Food Packaging and Shelf Life, 21, 100366.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2019 Citation: Yu, Z., Wang, W., Sun, L., Kong, F., Lin, M., Mustapha, M.* 2019. Preparation of cellulose nanofibril/titanium dioxide nanoparticle nanocomposites as fillers for PVA-based packaging and investigation into their intestinal toxicity. International Journal of Biological Macromolecules. In press.


Progress 03/01/18 to 02/28/19

Outputs
Target Audience:Audiences were food scientists, students, professionals from academia, the food industry, and government agencies. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training for two doctoral students and two Master's students. How have the results been disseminated to communities of interest?The results of this project will be disseminated in peer-reviewed journals, at the professional conferences including IFTconferencein 2019. What do you plan to do during the next reporting period to accomplish the goals?We will continue to study develop and validate separation and extraction methods for the efficient capture of foodborne contaminants from fresh produce and develop a SERS platform for rapid detection and quantification of both chemical and biological contaminants in samples. We will develop a rapid and direct "wipe-and-extract" method based on hybrid nanocellulose films coupled with SERS for screening samples; and a novel separation/detection method using plasmofluidic devices integrated with micro electrophoresis.

Impacts
What was accomplished under these goals? During the reporting period, experiments were carried out todevelop surface-enhanced Raman spectroscopy (SERS) method coupled with polyhedral gold nanostars (AuNS) to detect pesticide residues in fresh produce and juice products. AuNS are multi-branched three-dimensional metal nanostructures with roughened surface structures that can induce surface plasmons. A facile synthesis of AuNS was achieved using a two-step method. A Raman reporter molecule (4-aminothiophenol) was used to evaluate the performance of the SERS method and fingerprint-like Raman spectra were obtained. The sensitivity of SERS could reach a level of 10mg/kg. SERS coupled with AuNS was used to detect thiram residues in peach juice and the detection limit was 50mg/kg, which is 100 times more sensitive than using normal gold nanoparticles. These results demonstrate that AuNS are excellent substrates for SERS measurement, which has great potential for rapid detection of chemical contaminants in food products. The surface of the AuNS is rougher than nanoparticles, enabling them to adsorb more pesticide molecules on the surface. The nanocellulose membranes were immersed in different AuNS or nanoparticle solutions in a comparison study. The next step of the experiment is to enhance the surface adsorption capacity of the membrane by changing the surface charge of the solution, increase the Raman signals, and prepare a nanocellulose platform for "wipe-and-test" studies. Another study is to develop hybrid Au@Ag nanoparticles as SERS substrates for detection of commonly used pesticides in fresh produce. Briefly, gold nanoparticles were made by the reduction of gold (III) chloride hydrate using trisodium citrate. A volume of 100 mL of 0.02% (w/w) HAuCl4was reduced by 1500 μL of 1% (w/w) trisodium citrate solution at boiling temperature under vigorous magnetic stirring. The as-prepared gold nanoparticles were used as seed particles. Then, 600 μL of AgNO3solution (0.5% w/w) was added to the boiling gold nanoparticle solution. A volume of 1 mL of sodium citrate solution (1% w/w) was then used as the reducing agent. The Au@Ag hybrid nanoparticles synthesized by this method were 20 nm in diameter with a 2-3 nm silver as an outer coating layer. These nanoparticles showed a negative charge of -43 mV and were stable for 10 days. Successful synthesis of the hybrid nanoparticles was determined by measuring a probe molecule, 4-mercaptobenzoic acid (4-MBA). Different pesticides were tested using these nanoparticles and thiram and phorate showed the highest intensities. Satisfactory results were obtained for different concentrations of thiram solutions (0.01, 0.05, 0.1, 0.5, 1, 5, 10, and 50 ppm). To detect the pesticide in tomatoes, different methods were employed to extract the pesticide from the tomato peel. Organic tomatoes were thoroughly washed and soaked for 30 min in distilled water. Given designated pesticide concentration on tomato, the mass of pesticide (microgram) spiked on 1 cm2of tomato skin was obtained. Then, pesticide solutions were dropped on a piece of ~4 cm2fruit skin freshly peeled from a tomato. The skin of the samples were then air-dried, cut into small pieces, and placed in conical tubes containing 4 mL of mixed solvent (acetone/ H2O 1:1, v/v). After vigorous vortexing for 1 min, the mixture was sonicated using an ultrasonic bath for 5 min. Finally, the supernatant was filtered using a filter paper Whatman #1 and used for SERS detection. "Fingerprint-like" Raman spectra were obtained from various samples, which will be analyzed at the next step. The microfluidic deviceswereprepared based on a multi-step procedure. First, the silicon wafer was conditioned through three steps:washing with distilled water while undergoing sonication for 5 min; washing with isopropyl alcohol (IPA) while undergoing sonication for 5 min; washing with acetone while undergoing sonication for 5 min. The silicon wafer was dried by nitrogen gas. After preparation of the silicon wafer, SU-8 was coated on a silicon wafer using a spincoater.Atthis step, the spin speed was varied to obtain SU-8 films with different thicknessesto optimize the structures ofmicrofluidic devices. SU-8 covered silicon wafer was undergone soft baking at 95oC for 5 min. Thepatterns of themicrofluidic deviceweredetermined by photomasks. The exposure time is an important factor to be optimized. The optimum exposure time was found to be80 seconds. After exposure, the wafer was immediately submerged in SU-8 developer solution. Another important parameter that requires optimization is the developing time. The optimum value for developing time was found to be 9 minand 40 seconds. Meanwhile, the thickness of the SU-8 coverage was also evaluated using an Optical Photometer to have a uniform thickness on the surface of silicon wafer. The pattern on SU-8 coat was thentransferred topolydimethylsiloxane (PDMS)by molding it in the PDMS precursor.SEM imagesindicated successful molding, showing a thickness of 8-10µmofPDMS patternsthat wereequivalent to the SU-8patterns. The rest of the experiment was to put tubes in the inlets and outlets and form the real channels based on the design. The patternswere designed with different widthsand lengthsto choose the best channel that matches our purpose.

Publications

  • Type: Journal Articles Status: Submitted Year Published: 2018 Citation: Asgari, S., Saberi, A.H., McClements, D.J., Lin, M.* Microemulsions as nanoreactors for synthesis of biopolymer nanoparticles. Trends in Food Science & Technology. Submitted.
  • Type: Journal Articles Status: Submitted Year Published: 2018 Citation: Su, J.-W., Gao, W., Trinh, K., Kenderes, S.M., Tekin Pulatsu, E., Zhang, C., Whittington, A., Lin, M., Lin, J.* 2018. 4D Printing of Polyurethane Paint Based Composites. International Journal of Smart and Nano Materials. Submitted.