“School of Nano-Sciences”

Back to Papers Home
Back to Papers of School of Nano-Sciences

Paper   IPM / Nano-Sciences / 16918
School of Nano Science
  Title:   Speckle tweezers for manipulation of high and low refractive index micro-particles and nano-particle loaded vesicles
1.  Ramin Jamali
2.  Farzaneh Nazari
3.  Azadeh Ghaffari
4.  Sabareesh Velu
5.  Ali Reza Moradi
  Status:   Published
  Vol.:  2021
  Year:  2021
  Supported by:  IPM
Several fundamental research and applications in biomedicine and microfluidics often require controlled manipulation of suspended micro- and nanoscale particles. Speckle tweezers (ST) by incorporating randomly distributed light fields have been used to control microparticles with refractive indices higher than their medium and to perform manipulation tasks such as guiding and sorting. Indeed, compared to periodic potentials, ST represents a wider possibility to be operated for such tasks. Here, we extend the usefulness of ST into micro-particles of low index with respect to the surrounding. Repelling of such particles by high intensity regions into lower intensity regions makes them to be locally confined, and the confinement can be tuned by changing the average grain intensity and size of the speckle patterns. Experiments on polystyrenes and liposomes validate the procedure. Moreover, we show that ST can also manipulate the nanoparticle (NP)-loaded liposomes. Interestingly, the different interactions of NP-loaded and empty liposomes with ST enable collective manipulation of their mixture using the same speckle pattern, which may be explained by inclusion of the photophoretic forces on NPs. Our results on the different behaviors between empty and non-empty vesicles may open a new window on controlling collective transportation of drugmicro-containers alongwith itswide applications in soft matter.

Download TeX format
back to top
scroll left or right