Abstract
In this article, we demonstrated a handheld smartphone fluorescence microscope (HSFM) that integrates dual-functional polymer lenses with a smartphone. The HSFM consists of a smartphone, a field-portable illumination source, and a dual-functional polymer lens that performs both optical imaging and filtering. Therefore, compared with the existing smartphone fluorescence microscope, the HSFM does not need any additional optical filters. Although fluorescence imaging has traditionally played an indispensable role in biomedical and clinical applications due to its high specificity and sensitivity for detecting cells, proteins, DNAs/RNAs, etc., the bulky elements of conventional fluorescence microscopes make them inconvenient for use in point-of-care diagnosis. The HSFM demonstrated in this article solves this problem by providing a multifunctional, miniature, small-form-factor fluorescence module. This multifunctional fluorescence module can be seamlessly attached to any smartphone camera for both bright-field and fluorescence imaging at cellular-scale resolutions without the use of additional bulky lenses/filters; in fact, the HSFM achieves magnification and light filtration using a single lens. Cell and tissue observation, cell counting, plasmid transfection evaluation, and superoxide production analysis were performed using this device. Notably, this lens system has the unique capability of functioning with numerous smartphones, irrespective of the smartphone model and the camera technology housed within each device. As such, this HSFM has the potential to pave the way for real-time point-of-care diagnosis and opens up countless possibilities for personalized medicine.
Highlights
Fluorescence microscopy is ubiquitous in applications ranging from biological research[1,2,3,4,5] and healthcare[6,7] to environmental monitoring[8,9] and food sanitation[10,11]
If the lens does not protrude accessibly from the rear of the phone, the two-droplet lens can first be formed on a glass disk that is coated with a thin PDMS film and transferred onto the camera housing; the camera lens has a thin layer of PDMS deposited on it so that we can properly secure the lens
In addition to optical magnification, the lens dyed with coloured solvents contributes another attractive feature, i.e., light filtering
Summary
Fluorescence microscopy is ubiquitous in applications ranging from biological research[1,2,3,4,5] and healthcare[6,7] to environmental monitoring[8,9] and food sanitation[10,11]. In the fields of biomedical study and clinical applications, fluorescence imaging allows the detection and tracking of cells, proteins, and other molecules of interest in a specimen with high sensitivity and precision[12,13,14,15,16,17,18]. Dai et al Light: Science & Applications (2019)8:75 Based on these unique features, several smartphonebased microscopes have been demonstrated and are attracting increasing interest[26,27,28,29,30,31,32]. Throughout these research efforts, the key elements for a smartphone-based fluorescence microscope, such as light-emitting diodes (LED) for illumination, external lenses for optical imaging and proper magnification, and fluorescence emission filters for routing light, have been developed. If the propagation of the excitation light is not against the detection path, inexpensive plastic colour filters are acceptable for creating dark-field backgrounds[33]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
