Type
ArticleAuthors
Wei, QingshanAcuna, Guillermo
Kim, Seungkyeum
Vietz, Carolin
Tseng, Derek
Chae, Jongjae

Shir, Daniel
Luo, Wei
Tinnefeld, Philip
Ozcan, Aydogan

Date
2017-05-12Permanent link to this record
http://hdl.handle.net/10754/625119
Metadata
Show full item recordAbstract
Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses. An important need in smartphone-based microscopy and sensing techniques is to improve the detection sensitivity to enable quantification of extremely low concentrations of target molecules. Here, we demonstrate a general strategy to enhance the detection sensitivity of a smartphone-based fluorescence microscope by using surface-enhanced fluorescence (SEF) created by a thin metal-film. In this plasmonic design, the samples are placed on a silver-coated glass slide with a thin spacer, and excited by a laser-diode from the backside through a glass hemisphere, generating surface plasmon polaritons. We optimized this mobile SEF system by tuning the metal-film thickness, spacer distance, excitation angle and polarization, and achieved ~10-fold enhancement in fluorescence intensity compared to a bare glass substrate, which enabled us to image single fluorescent particles as small as 50 nm in diameter and single quantum-dots. Furthermore, we quantified the detection limit of this platform by using DNA origami-based brightness standards, demonstrating that ~80 fluorophores per diffraction-limited spot can be readily detected by our mobile microscope, which opens up new opportunities for POC diagnostics and sensing applications in resource-limited-settings.Citation
Wei Q, Acuna G, Kim S, Vietz C, Tseng D, et al. (2017) Plasmonics Enhanced Smartphone Fluorescence Microscopy. Scientific Reports 7. Available: http://dx.doi.org/10.1038/s41598-017-02395-8.Sponsors
The Ozcan Research Group at UCLA gratefully acknowledges the support of the Presidential Early Career Award for Scientists and Engineers (PECASE), the Army Research Office (ARO; W911NF-13-1-0419 and W911NF-13-1-0197), the ARO Life Sciences Division, the National Science Foundation (NSF) CBET Division Biophotonics Program, the NSF Emerging Frontiers in Research and Innovation (EFRI) Award, the NSF EAGER Award, NSF INSPIRE Award, NSF Partnerships for Innovation: Building Innovation Capacity (PFI:BIC) Program, Office of Naval Research (ONR), the National Institutes of Health (NIH), the Howard Hughes Medical Institute (HHMI), Vodafone Americas Foundation, the Mary Kay Foundation, Steven & Alexandra Cohen Foundation, and KAUST. This work is based upon research performed in a laboratory renovated by the National Science Foundation under Grant No. 0963183, which is an award funded under the American Recovery and Reinvestment Act of 2009 (ARRA). G.A. acknowlegdes support from Deutsche Forschungsgemeinschaft (DFG, AC 279/3-1). C.V. is greatful for funding of the Studienstiftung des Deutschen Volkes.Publisher
Springer NatureJournal
Scientific ReportsISSN
2045-2322ae974a485f413a2113503eed53cd6c53
10.1038/s41598-017-02395-8