The Use of Ultrasounds in the Preparation of Chemosensory Microstructures

Abstract

In many fields, the goal is to obtain structures with small dimensions in the order of micro/nanometers. Small-sized systems can have countless applications in various industries such as cosmetology, medicine, and nutrition technology. Many techniques are used to obtain the most miniature possible spheres, such as interference with the composition, use of surfactants, or mechanical interference: rapid mixing, increased pressure, and ultrasound. The use of ultrasound in the development of colloidal systems can be an effective method of reducing the size of particles of dispersed phase and influencing the functions they represent. An important aspect here is the time during which the ultrasound is used. In this work, the influence of ultrasound on the chemosensory properties and size of produced ion-sensitive microspheres was investigated and compared. The chemosensory response of the developed microspheres was studied using spectrophotometry and spectrofluorimetry, while the size of the microsphere optodes was estimated by confocal microscopy.

Toward an Electronic Tongue Based on Surfactant-Stabilized Chemosensory Microparticles with a Dual Detection Mode

“…In agreement with our previous studies, 32,33 AS-ISE and CS-ISE displayed generic anion-and cation selectivities, respectively (Figure 4a,b). The highest anionic responses of AS-ISE were observed at pH 4.5 and were comparable for DA, VMA, and NM.…”

“…The microspheres selective for both anions (A) and cations (C) contained a chromoionophore (CH) as an optical transducer, which can be protonated/deprotonated in the presence of an ion exchanger (R). This change in the protonation degree of the chromoionophore is responsible for the change in the optical properties of the produced microspheres according to eqs and (for AS-MPs and CS-MPs, respectively). ,, The next two types of microspheres were incorporated with the manganese porphyrins, which played the double role of an ionophore and an optical transducer, according to eqs and . CH normalm + normalR normalm + + normalH aq + + normalA aq − ⇆ CHH normalm + + normalR + normalA normalm − CHH normalm + + normalR normalm − + normalC aq + ⇆ CH normalm + normalH aq + + normalC + normalR normalm − MnOEPCl normalm + normalA aq − ⇆ MnOEPA normalm …”

“…Their size depends on many factors such as mixing speed during fabrication, the type and concentration of components, etc., which were confirmed in our previous studies. 32,33 Although STEM allowed for direct imaging of the microparticles, confirming their spherical shape, the STEM sample preparation (solvent evaporation) may affect the observed size of the spheres due to aggregation. To confirm the presence of nano-/microspheres in the undiluted dispersion of the MP optodes, the particle size distribution was analyzed using dynamic light scattering (DLS, Figure 1D).…”

“…31 Their composition can be optimized to achieve the desired properties in terms of the selectivity pattern and particle size. 6,32,33 Moreover, their pH cross-response and limited selectivity toward specific ions, which would be considered disadvantageous in classical sensing, are in fact advantageous in differential sensing. 6 Therefore, in this work, we propose a novel type of electronic tongue based on chemosensory microparticles (MPs) with a lipophilic core stabilized by a nonionic poloxamer surfactant.…”

Chemosensory Optode Array Based on Pluronic-Stabilized Microspheres for Differential Sensing

“…For all experiments except the study of stability in time, freshly prepared optode microsphere suspensions were used. Their size in a range of a few micrometers was confirmed by confocal microscopy (the microscope images were provided in our recent publications [17,18]).…”