Recent reports highlighting the role of particle geometry have suggested that anisotropy can affect the rate and the pathway of particle uptake by cells. Therefore, we investigate the internalization by cells of porous calcium carbonate particles with different shapes and anisotropies. We report here on a new method of the synthesis of polyelectrolyte coated calcium carbonate particles whose geometry was controlled by varying the mixing speed and time, pH value of the reaction solution, and ratio of the interacting salts used for particle formation. Uptake of spherical, cuboidal, ellipsoidal (with two different sizes) polyelectrolyte coated calcium carbonate particles was studied in cervical carcinoma cells. Quantitative data were obtained from the analysis of confocal laser scanning microscopy images. Our results indicate that the number of internalized calcium carbonate particles depends on the aspect ratio of the particle, whereby elongated particles (higher aspect ratio) are internalized with a higher frequency than more spherical particles (lower aspect ratio). The total volume of internalized particles scales with the volume of the individual particles, in case equal amount of particles were added per cell.

Recent studies have revealed that a variety of shaped particles can interact with cells in a different way. Elongated particles can be effectively and quickly internalized intercellularly compared with other configurations. Herein we present the potential of fabrication of anisotropic polyelectrolyte multilayer capsules formed by coating spherical, ellipsoid-like and square calcium carbonate (CaCO₃) particles. By varying the intermixing speed, time, pH value and ratio of initial ingredients during precipitation such CaCO₃ templates are produced. Particles loaded with FITC–dextran and coated with polyelectrolytes could maintain the templated shape after core removal. Quantitative data are derived from analysis of confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) measurements.

Surface-enhanced Raman scattering (SERS) has emerged as an excellent analyticaltool for the effective detection and fingerprint identification of variouschemicals. Recently, significant progress has been made in the fabrication of SERS-active substrates using simple, inexpensive, and affordable methods. The full potentialof universal SERS diagnostics will likely be realized with the development of approaches and devices capable of effectively detecting analytes on varioussurfaces as well as in multicomponent media. In addition, the combination of implantable or wearable SERS-active substrates and remote portable devices enables real-time diagnostics that ideally fit the concept of personalized medicine. In this paper, we summarize recent achievements in fabricating flexible SERSsubstrates made of cellulose paper, polymer membranes, and textile fibrousfilms. Emphasis is placed on the in-situ extraction and detectionof various chemicals in real-world surfaces and complex media using flexible nanofibrous SERS platforms. The potential SERS applications and future perspectivesin on-site diagnostics are also discussed. Open image in new window