A review of thermal impact of surface acoustic waves on microlitre droplets in medical applications

Mubbashar Mehmood, Umar F. Khan, Ali O. M. Maka, Javed Akhter*, Tariq Nawaz Chaudhary, Faisal Masood, Sameer Ahmad Hasan, Yeaw Chu Lee

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

2 Citations (Scopus)
44 Downloads (Pure)


The surface acoustic waves (SAW) propagate inside the microdroplets resulting in kinetic and thermal impacts. The kinetic drives fluid particles inside the droplet while thermal impact increases the liquid’s temperature. This paper provides a comprehensive review of the research investigations related to internal kinetics and heating inside the microdroplet caused by the acoustic waves. The main factors that affect the kinetics and convection heat transfer are the piezoelectric materials, shape of the interdigital transducer (IDT) and mode of acoustic waves. Internal streaming (kinetic) leads to particle mixing, particle manipulation, cell sorting, cell patterning, cell separation, measuring the concentration of immunoglobulin and so forth. The effect of changing the mode of waves and the shape of IDT on the relevant applications are presented. Internal convection heat transfer is important where heating of the liquid is essential for many applications such as monitoring blood coagulation in the human plasma and an acoustic tweezer for particle trapping. Experimental methods developed by researchers to realise uniform temperature with constant heating and cooling cycles are also discussed. Such methods are widely used in the polymerase chain reaction (PCR) to detect COVID-19 infection. The heating of the droplet can be efficiently controlled by changing the input power and by varying the duty factor.

Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalAdvances in Mechanical Engineering
Issue number8
Publication statusPublished - 1 Aug 2022


  • acoustothermal
  • droplet microfluidics
  • piezoelectric material
  • polymerase chain reaction (PCR)
  • Surface acoustic wave (SAW)
  • temperature control

ASJC Scopus subject areas

  • Mechanical Engineering


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