Portable quantitative phase microscope for material metrology and biological imaging

Quantitative phase microscopy(QPM)has emerged as an important tool for material metrology and biological imaging.For broader adoption in those applications,we have proposed and demonstrated a new portable off-axis QPM method,which works in both transmission and reflection modes to meet different sample measurement requirements.The temporal and spatial sensitivities of our system,as quantified by optical path-length difference values,are 0.65 nm and 1.04 nm,respectively.To demonstrate its applicability for a wide range of applications,we deployed our system for profiling transistor gold electrode samples,observing red blood cell membrane fluctuations,imaging living cells flowing in a microfluidic chip,etc.Our portable QPM system has a low-cost design and involves a simple and robust phase-retrieval algorithm that we envision will allow for broader deployment at different environmental settings,including in resource-limited sites and integration with other metrology or imaging modalities.

Double emulsion-pretreated microwell culture for the in vitro production of multicellular spheroids and their in situ analysis

Multicellular spheroids have served as a promising preclinical model for drug efficacy testing and disease modeling.Many microfluidic tech no logies,in eluding those based on water-oil-water double emulsions,have been introduced for the production of spheroids.However,sustained culture and the in situ characterization of the gen erated spheroids are currently unavailable for the double emulsion-based spheroid model.This study presents a streamlined workflow,termed the double emulsion-pretreated microwell culture(DEPMiC),incorporating the features of(1)effective initiation of uniform-sized multicellular spheroids by the pretreatment of double emulsions produced by microfluidics without the requirement of biomaterial scaffolds;(2)sustained maintenance and culture of the produced spheroids with facile removal of the oil confinement;and(3)in situ characterization of individual spheroids localized in microwells by a built-in analytical station.Characterized by microscopic observations and Raman spectroscopy,the DEPMiC cultivated spheroids accumulated elevated lipid ordering on the apical membran巳similar to that observed in their Matrigel counterparts.Made possible by the proposed tech no logical advancement,this study subsequently examined the drug responses of these in vitro-generated multicellular spheroids.The developed DEPMiC platform is expected to gen erate health benefits in personalized cancer treatment by offering a pre-animal tool to dissect heterogeneity from individual tumor spheroids.

On-demand light-driven release of droplets stabilized via a photoresponsive fluorosurfactant

Water-in-oil droplets have emerged as promising microreactors for high-throughput biochemical analysis due to their features of reduced sample consumption and automated operation.For a typical screening application,droplets are often trapped for continuous monitoring of the reaction over an extended period,followed by the selective retrieval of targeted droplets based on the after-effect of biochemical reactions.While techniques for droplet trapping are well developed,retrieval of targeted droplets mainly demands complicated device fabrication or sophisticated control.Herein,facile and rapid selective droplet release is achieved by utilizing a new class of photoresponsive fluorosurfactant based on plasmonic nanoparticles.The intense photothermal response provided by this novel photoresponsive fluorosurfactant is capable of vaporizing the fluorocarbon oil at the droplet interface under laser illumination,resulting in a bubble releasing a trapped droplet on demand.A fully automated fluorescence-activated droplet release platform has also been developed to demonstrate its potential for droplet-based large-scale screening applications.