Interactions of Nanoparticles and Biosystems: Microenvironment of Nanoparticles and Biomolecules in Nanomedicine.

Nanotechnology is a multidisciplinary science covering matters involving the nanoscale level that is being developed for a great variety of applications. Nanomedicine is one of these attractive and challenging uses focused on the employment of nanomaterials in medical applications such as drug delivery. However, handling these nanometric systems require defining specific parameters to establish the possible advantages and disadvantages in specific applications. This review presents the fundamental factors of nanoparticles and its microenvironment that must be considered to make an appropriate design for medical applications, mainly: (i) Interactions between nanoparticles and their biological environment, (ii) the interaction mechanisms, (iii) and the physicochemical properties of nanoparticles. On the other hand, the repercussions of the control, alter and modify these parameters in the biomedical applications. Additionally, we briefly report the implications of nanoparticles in nanomedicine and precision medicine, and provide perspectives in immunotherapy, which is opening novel applications as immune-oncology.

Enhanced cytotoxic activity of bile acid cisplatin derivatives by conjugation with gold nanoparticles.

This article explores the potential cytotoxic activity of bile-acid cisplatin derivatives like bisursodeoxycholate(ethylenediamine)platinum(II), PtU2, when conjugated with gold nanoparticles, being a promising alternative to cisplatin in the treatment of cancer due to their lower toxicity. For our purpose we analyzed the intracellular delivery ability of these compounds after conjugation with 20-nm gold nanoparticles (PtU2-AuNPs) in the MG63 (osteosarcoma) cell line. Same platinum uptake after incubation with PtU2 and PtU2-AuNPs-derivatives is associated with a higher cytotoxic activity in case of the platinum-gold nanoparticle conjugate, the overall IC50 of PtU2 being reduced more than 10 fold for these new conjugates. When conjugated with gold nanoparticles, this bile-acid derivative is more efficient than the platinum compound alone in terms of their cytotoxic activity.

Procedures for controlling the size, structure and optical properties of CdS quantum dots during synthesis in aqueous solution.

We report an easy approach for the synthesis of CdS Quantum Dots (CdS QDs) with high luminescence and temporal stability through the reaction of Cd(2+) and S(2-) in the presence of mercaptoacetic acid (MAA) as a capping reagent in aqueous medium, under normal pressure and room temperature. The influence of several experimental variables, including temperature, pH, the Cd/S ratio and the Cd/MAA ratio, on the optical properties of the QDs obtained was studied systematically. The experimental results indicate that these variables play an important role in determining the size and state of the surface of the nanoparticles, and hence their luminescent properties and temporal stability. The general aspects of nanocrystal nucleation and growth in the synthesis of nanocrystals were studied. The best conditions for the synthesis of nanoparticles of high quality are also reported. The CdS nanocrystals obtained exhibited a narrow PL band, with reproducible room-temperature quantum yields.

A gas diffusion technique coupled with flow injection systems. Optimization of the process in its application to the fluorimetric determination of ammonium in water samples.

A novel flow injection-gas-diffusion (GD-FI) system has been developed for the on-line analysis of ammonium ion in waters with fluorimetric detection, using an acceptor solution containing the Eosin-Bluish (EB) acid-base indicator. This, together with optimization of the process of gas transfer through the membrane, increases the sensitivity of the method to a considerable extent. Under optimum conditions, it is possible to determine the analyte within the 0.02-1.5 mg l(-1) range, with a limit of detection of 5 microg l(-1) and relative standard deviations (n = 12, [NH (4) (+) ] = 50 microg l(-1) and 0.05 microg l(-1)) of 3.4% and 3.0% respectively. The determination rate was 15 samples per hour.