Since the pioneering work of Ashkin and coworkers, back in 1970, optical manipulation gained an increasing interest among the scientific community. manipulation is used in combination with microfluidic devices. We will distinguish on the optical method COL24A1 implemented and three main categories will be presented and explored: (i) a single highly focused beam used to manipulate the sample, (ii) one or more diverging beams imping on the sample, or (iii) evanescent wave based manipulation. strong class=”kwd-title” Keywords: optical manipulation, microfluidics, optofluidics, optical trap, optical tweezers, optical stretcher 1. Introduction Radiation pressure was first introduced by J. Indocyanine green small molecule kinase inhibitor C. Maxwell in his theory of electromagnetism. It is the easiest and the most intuitive example of an optical force: light incident on a surface gives rise to a force on that surface. Being the intensity of optical forces rather small, from femto- to nano-Newtons, they are only effective on microscopic objects ranging from tens of nanometers to a huge selection of micrometers. A genuine increase in the exploitation of optical makes to control physical items occurred using the invention from the optical tweezers by Ashkin and coworkers [1,2]. An optical tweezer exploits forces exerted with a focused Gaussian laser to capture little items strongly. It can capture items with measurements which range from 5 nm to 100 m [3,4], and may exert makes to 100 pN with good resolutions [5 up,6,7,8,9]. This range is specially interesting in the natural field because it corresponds to organelles and cells measurements, to inter- and intra-cellular procedures hence. The physical concepts behind optical tweezers could be ascribed to different systems whether the items are much smaller sized or much bigger compared to the wavelength of light. In the 1st case, the lamps electrical field induces a power dipole second in the thing that is drawn toward the concentrate by the strength gradients from the electrical field [10]. In the next case, Mie scattering circumstances are satisfied as well as the problem could be resolved by ray optics: bigger items act as lens refracting the rays of light and changing the momentum of photons, Indocyanine green small molecule kinase inhibitor this provides you with rise to recoil that pulls the object on the concentrate [11,12]. The optical force is usually described as the sum of two components: a scattering force, which pushes the particle along the propagation direction of the incident light, and a gradient force that pulls the particle towards the highest intensity region and is due to the spatial intensity gradient. Stable trapping is obtained when the gradient force counterbalances the scattering force. To satisfy this condition, a steep spatial gradient of the beam intensity is needed, Indocyanine green small molecule kinase inhibitor hence optical tweezers are usually realized by exploiting microscope objectives where high numerical apertures allow for focusing the light Indocyanine green small molecule kinase inhibitor as tightly as possible [13]. Optical tweezers (OT) have been used for many diverse applications ranging from chemistry and physics to medicine and biology. In physical sciences, the capability of optical tweezers to manipulate matter in a noninvasive way allowed for studies Indocyanine green small molecule kinase inhibitor in classical statistical mechanics, as, for example, measurements of macromolecular interactions in colloidal systems [14,15]. In medical and biological applications, optical tweezers have been exploited to characterize the forces exerted by molecular motors or, at the single cell level they have been used to study single cell mechanical properties by evaluating membrane elasticity. Moreover, they have been also exploited to probe viscoelastic properties of various samples, from single biopolymers as DNA to aggregated protein fibres [2,16,17]. Optical tweezers have been also exploited in areas, such as in vitro fertilization or in microsurgery to optoporate cells for chromosome and gene modifications [18,19,20]. Optical tweezers have been successfully used in many applications; also with the addition of different functionalities that have been implemented, e.g., sample rotation when beams with complex wavefronts are exploited [21]. Nevertheless, they still suffer from.