Nanoparticles from conventional cellulose esters: evaluation of preparation methods

Cellulose/Cellulose-Based Nanospheres: Perspectives and Prospective

“…In general, this process results in cellulose-based nanospheres dispersed in water with diameters in the range of 50-300 nm, with spherical shape and relatively narrow size distribution (Table 1). 13,19,24,25,57 Desgouilles indicated that final nanospheres prepared from the solvent evaporation process are formed through a dynamic process involving the possible coalescence between emulsion droplets when the organic solvent diffuses from the inside of the particles. 13 Thus, the diameter of the final nanospheres is determined by the size of firstly formed emulsion droplets and the polymer chain conformation in the solvent.…”

“…13 Studies report that the diameter of nanospheres is independent of molecular weight and chemical structure of cellulose derivatives or the entrapped guest molecules. 13,19,24,57 The most important factors regulating droplet size and distribution are surfactant choice and input energy during emulsion formation.…”

“…19 Decreases in sonication energy favor broader particle size distribution. 28 Hydrophilic drugs benefit from the use of alternative methods such as oil-in-oil (O/O) emulsions, since hydrophilic molecules do not dissolve in either oil phase.…”

“…Figure 1 depicts several examples of nanospherical cellulosic particles made by different processes. [18][19][20][21][22] In general, solid particles, as in Fig. 1a, exhibit appreciable crystallinity and are likely to be impermeable.…”

“…Particles formed by emulsion processes, nanoprecipitation, microfluidics, or selfassembly approaches tend to provide opportunities for incorporation and controlled release of drugs, fragrances, or other small ''guest'' molecules. [19][20][21] The fraction of particle volume occupied by liquids and guest molecules is likely to vary with time and environmental parameters such as temperature, pressure, humidity, pH, etc. For example, the same particle will exhibit diameter changes of 50% or more when data obtained from ''wet' samples by techniques like dynamic light scattering (DLS) are compared with data obtained under ''dry'' conditions, as in transmission electron microscopy (TEM); in terms of volume, the data show an 8-fold change.…”