title: High-throughput and label-free single nanoparticle sizing based on time-resolved on-chip microscopy.
abstract: Sizing individual nanoparticles and dispersions of nanoparticles provides invaluable information in applications such as nanomaterial synthesis, air and water quality monitoring, virology, and medical diagnostics. Several conventional nanoparticle sizing approaches exist; however, there remains a lack of high-throughput approaches that are suitable for low-resource and field settings, i.e., methods that are cost-effective, portable, and can measure widely varying particle sizes and concentrations. Here we fill this gap using an unconventional approach that combines holographic on-chip microscopy with vapor-condensed nanolens self-assembly inside a cost-effective hand-held device. By using this approach and capturing time-resolved in situ images of the particles, we optimize the nanolens formation process, resulting in significant signal enhancement for the label-free detection and sizing of individual deeply subwavelength particles (smaller than λ/10) over a 30 mm(2) sample field-of-view, with an accuracy of ±11 nm. These time-resolved measurements are significantly more reliable than a single measurement at a given time, which was previously used only for nanoparticle detection without sizing. We experimentally demonstrate the sizing of individual nanoparticles as well as viruses, monodisperse samples, and complex polydisperse mixtures, where the sample concentrations can span ∼5 orders-of-magnitude and particle sizes can range from 40 nm to millimeter-scale. We believe that this high-throughput and label-free nanoparticle sizing platform, together with its cost-effective and hand-held interface, will make highly advanced nanoscopic measurements readily accessible to researchers in developing countries and even to citizen-scientists, and might especially be valuable for environmental and biomedical applications as well as for higher education and training programs.
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Euan
authors: E
authors: McLeod
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: T Umut
authors: TU
authors: Dincer
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Muhammed
authors: M
authors: Veli
authors: ‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Yavuz N
authors: YN
authors: Ertas
authors: Chau
authors: C
authors: Nguyen
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Wei
authors: W
authors: Luo
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Alon
authors: A
authors: Greenbaum
authors: ‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.
authors: Alborz
authors: A
authors: Feizi
authors: †Electrical Engineering Department, University of California, Los Angeles, California 90095, United States.|‡Bioengineering Department, University of California, Los Angeles, California 90095, United States.|⊥California NanoSystems Institute, University of California, Los Angeles, California 90095, United States.|∥Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, California 90095, United States.
authors: Aydogan
authors: A
authors: Ozcan
mesh_terms: D003362:Cost-Benefit Analysis; D006696:Holography; D008853:Microscopy / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry; D014835:Volatilization
chemical_list: D011137:Polystyrenes
keywords: field-portable; lensfree microscopy; nanoparticles; particle-sizing