Euisuk Chung

Mr. Euisuk Chung


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 August 2023 in Nanomaterials
Verified
Journal Article
Open access
PDF file
AZAndrew Zhao
Andrew Zhao
YZYiying I. Zhu
Yiying I. Zhu
ECEuisuk Chung
Euisuk Chung
JLJeehyun Lee
Jeehyun Lee
SMSamuel Morais
Samuel Morais
SEStanislav Emelianov
Stanislav Emelianov
Perfluorocarbon nanodroplets (PFCnDs) are sub-micrometer emulsions composed of a surfactant-encased perfluorocarbon (PFC) liquid and can be formulated to transiently vaporize through optical stimulation. However, the factors governing repeated optical droplet vaporization (ODV) have not been investigated. In this study, we employ high-frame-rate ultrasound (US) to characterize the ODV thresholds of various formulations and imaging parameters and identify those that exhibit low vaporization thresholds and repeatable vaporization. We observe a phenomenon termed “preconditioning”, where initial laser pulses generate reduced US contrast that appears linked with an increase in nanodroplet size. Variation in laser pulse repetition frequency is found not to change the vaporization threshold, suggesting that “preconditioning” is not related to residual heat. Surfactants (bovine serum albumin, lipids, and zonyl) impact the vaporization threshold and imaging lifetime, with lipid shells demonstrating the best performance with relatively low thresholds (21.6 ± 3.7 mJ/cm2) and long lifetimes (t1/2 = 104 ± 21.5 pulses at 75 mJ/cm2). Physiological stiffness does not affect the ODV threshold and may enhance nanodroplet stability. Furthermore, PFC critical temperatures are found to correlate with vaporization thresholds. These observations enhance our understanding of ODV behavior and pave the way for improved nanodroplet performance in biomedical applications.