Effective particle analysis in biological heterogeneous liquids (as serum, plasma, urine, and cell lysate) is foreclosed to traditional analytical approaches relying on light scattering methods as DLS, SLS, NTA and Obscuration due to the presence of the biological components in target real solution. The capability of Classizer™ ONE and SPES patented method of discriminating single particle basing on their optical properties is of capital importance with heterogeneous biological systems. In particular, the advantage is rampant and unique when particles have to be counted and analysed directly in the biological target media to tailor the effectiveness of drug delivery product formulation or to study eco-/cito-toxicity effects of particle on ecosystems and human health.

Analysis in heterogeneous liquids

Analysis can be done at every steps of the particle formulation, even without purification or filtration

Particle discrimination

Particles are easily and in-line discriminated from the biological components and secondary populations

Immediately

Particle out of specifics as aggregation and aging in target bioliquids are detected to improve formulation

Monitored

The particles in bioliquids as plasma and cell lysate are monitored and their numerical concentration is quantified

Example of application: Study of drug carriers based on PLGA particles in human plasma
The emulsion of PLGA is a typical drug delivery model with clinical relevance due to the PLGA biocompatibility and the possibility to finely tune particle size and drug payloads. Classizer™ ONE is exploited to characterize polydisperse poly(lactic-coglycolic acid) (PLGA) particles synthesized by Oil-in-Water (OW) solvent evaporation emulsion technique, with and without PEG as surfactant, incubated in human plasma for 48h. Different particle agind due to the presence of surfactant is observed and particle behaviour in target liquids can be tailored.

(in figure) (TOP) (top) EOS CLOUDS for a heterogeneous sample of human plasma mixed with an emulsion of PLGA particles after 24h incubation at 37°C. PLGA population changed its optical properties and shifted to a location corresponding to lower refractive index. Red line represents expected size trend for PLGA particles at 0h as a reference. (down) EOS CLOUDS for a heterogeneous sample of human plasma mixed with an emulsion of PLGA stabilized with PEG particles after 24h incubation at 37°C. Data are compatible with results at 0h, resulting in no significant change in optical properties of particles thanks to PEG stabilization. Red line represents expected size trend for PLGA particles.

AppCases_Bioliquids_PS001

Example of application: Identification of NanoPlastic particles in unfiltered cell lysate
As a newly emerging pollutant, nanoplastics are easily to be ingested by organisms, and cause severe damage to biological functions because of their small size, high specific surface area and strong biological penetration. There are increasing reports of numerous airborne microplastics, including polystyrene, being detected in atmospheric samples, which implies a potential risk to the human respiratory system. A simple but effective feasibility study of the capability of SPES to detect the uptake of polystyrene particles in V79 cell studying the particles in the culture supernatant and in the cell lysate is reported.

(in figure) EOS CLOUDS for the heterogeneous samples of supernatants and cell lysates of polystyrene particles and cell V79. a) supernatant of cell culture V79 with PS 0.5µm spheres; b) supernatant of cell culture V79 with PS 1.0µm spheres; c) supernatant of cell culture V79 with a mix of PS 0.5µm and PS 1.0µm spheres; d) cell lysate of culture V79 with PS 0.5µm spheres; e) cell lysate of culture V79 with PS 0.5µm spheres; f) cell lysate of culture V79 with a mix of PS 0.5µm and PS 1.0µm spheres. Note. PS 0.5µm particles in cell lysate show different optical properties respect to PS 0.5µm particles in supernatant or in pure liquids as water (red cross indicates expected position). This effect suggests an interaction with the biological matter which modify the behavior and stability of the particles. On the contrary, the PS 1.0µm particles show no changes and are located where expected.

AppCases_Bioliquids_PS002