Gold nanoparticle coated silicon nitride chips for intracellular surface-enhanced raman spectroscopy

Using surface-enhanced Raman spectroscopy on gold-nanoparticle-decorated silicon nitride chips, we monitor the release of dextran-rhodamin molecules from capsules inside living cells. This demonstrates the feasibility of using photonic chips for intracellular sensing at visible wavelengths

Polycaprolactone-based, porous CaCO3 and Ag nanoparticle modified scaffolds as a SERS platform with molecule-specific adsorption

Surface-enhanced Raman scattering (SERS) is a high-performance technique allowing detection of extremely low concentrations of analytes. For such applications, fibrous polymeric matrices decorated with plasmonic metal nanostructures can be used as flexible SERS substrates for analysis of analytes in many application. In this study, a three-dimensional SERS substrate consisting of a CaCO3-mineralized electrospun (ES) polycaprolactone (PCL) fibrous matrix decorated with silver (Ag) nanoparticles is developed. Such modification of the fibrous substrate allows achieving a significant increase of the SERS signal amplification. Functionalization of fibers by porous CaCO3 (vaterite) and Ag nanoparticles provides an effective approach of selective adsorption of biomolecules and their precise detection by SERS. This new SERS substrate represents a promising biosensor platform with selectivity to low and high molecular weight molecules

Release from polyelectrolyte multilayer capsules in solution and on polymeric surfaces

Release from polyelectrolyte multilayer microcapsules represents one of the most important steps enabling practical use of the microcapsules. A number of biological and non-biological applications are envisaged by proper encapsulation of molecules of interest and their release performance. Since the invention of the microcapsules at the Max-Planck Institute of Colloids and Interfaces in 1998 the work towards microcapsule assistant release has undergone tremendous progress. Almost simultaneously with development of release approaches an extensive base of applications has been advanced. In this progress report the release from the capsules in a solution and those immobilized on the surface of polymeric films is addressed

Biocompatible chitosan nanofibers functionalized with silver nanoparticles for SERS based detection

Electrospun chitosan nanofibrous substrates are functionalized with silver nanoparticles by reduction of silver from Tollens reagent using glucose. Filling factor is estimated through developed protocol by using analysis of scanning electron microscopy images. Obtained nanocomposite silver-chitosan plasmonic films display reliable surface enhanced Raman scattering signal of rhodamine B with the concentration 10(-5) M adsorbed onto the surface of functionalized substrates

Gold nanoparticle coated silicon nitride chips for intracellular surface-enhanced Raman spectroscopy

Using surface-enhanced Raman spectroscopy on gold-nanoparticle-decorated silicon nitride chips, we monitor the release of dextran-rhodamin molecules from capsules inside living cells. This demonstrates the feasibility of using photonic chips for intracellular sensing at visible wavelengths

Containers for drug delivery based on vaterite particles

Calcium carbonate is an important inorganic biomaterial thanks to its chemical stability, bioactivity, and biocompatibility. These properties have recently made it an interesting candidate for drug delivery systems. Calcium carbonate exists in three anhydrous polymorphic modifications: vaterite, aragonite, and calcite. Under normal conditions, vaterite is an unstable phase, while calcite and aragonite are stable. The transition between these phases can be exploited as a payload release mechanism. Vaterite polycrystalline particles have further favorable properties like high porosity, large surface area, and negative zeta potential. In our work we present a novel technique for the synthesis and characterization of CaCO3 containers. Porous polycrystalline particles were fabricated with controllable average sizes from 400 nm up to 10 microns. For demonstration a wide range of particles applications drug system as the enzyme alkaline phosphatase (ALP) and low molecular weight Fluorescent anticancer photosensitizer –“ sulfonated aluminum phthalocyanines” was encapsulated to study payload release dynamics. ALP is a popular model protein as it is easily detectable spectrophotometrically. Furthermore, it is responsible for mineralization of bone tissue in vivo. Hence, ALP-loaded vaterite could be applied for bone regeneration. In addition, ALP has been applied as an anti-inflammation drug to combat certain diseases. Several levels of control on these release dynamics could be identified: 1) The immersion medium: capsules immersed in water, showed a delayed burst release of the dye, coinciding with the crystal phase transition from vaterite to calcite. In ethanol this phase transition was inhibited, consequently only a slow desorption of the encapsulated dye was found. 2) Surface modification: Covering microcontainers with additional layers of biocompatible polyelectrolyte increases the payload release time. 3) pH value: A change of the pH from neutral to acid conditions will instead lead to a destruction of the vaterite matrix leading to an immediate release. Moreover, we report on studies of vaterite containers in cell culture assays, evaluating their cytotoxicity, their influence on cell viability, and the particles’ uptake efficiency. The prove of principle to use such particles with encapsulated photosensitizer for photodynamic therapy were demonstrated. These flexible control mechanisms and the perfect biocompatibility have proven the system’s potential for future pharmaceutical applications like drug delivery or bone reconstruction material. We would like to thank the Russian Federation (grant number 14.Z50.31.0004 to support scientific research projects implemented under the supervision of leading scientists at Russian institutions and Russian institutions of higher education), and RFBR research project №15-29-01172. BP acknowledges support of FWO (Fonds Wetenschappelijk Onderzoek

Hybrid functional materials for tissue engineering : synthesis, in vivo drug release and SERS effect

The research presents the designing new hybrid biocompatible materials aimed to bone tissue engineering with enhanced osteoconductivity and functionality. The scaffolds consisted of electrospun polymeric matrix, modified with porous calcium carbonate (vaterite) coatings, were developed and studied. The subcutaneous implantation tests in vivo with white rats demonstrated the high degree of biocompatibility of vaterite-mineralized scaffolds. Moreover, the performed in vivo release of bioactive molecules, immobilized in mineral coating of scaffold, allowed to control the regeneration process in tissues in the implantation area. Also, the decoration of mineralized scaffold with silver nanoparticles exhibited the capability of exploiting these materials as effective substrates with providing surface enhanced Raman scattering (SERS) for precise detection of low concentrations of analyte. In this way, developed scaffolds can be promising materials with enhanced functionality of tissue regeneration, in vivo drug release and detection for designing novel smart devices for biomedicine