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Silica-based nanoparticles for applications in photodynamic therapy (PDT) have emerged as a promising field for the treatment of cancer. In this review, based on the pathway the photosensitizer is entrapped inside the silica matrix, the different methods for the synthesis of silica-based nanoparticles are described from the pioneering works to the latest achievements which concern multifunctional nanoplatforms, up-converting nanoparticles, two-photon PDT, vectorization and in vivo applications.

IntroductionTumor cells can effectively be killed by heat, e.g. by using magnetic hyperthermia. The main challenge in the field, however, is the generation of therapeutic temperatures selectively in the whole tumor region. We aimed to improve magnetic hyperthermia of breast cancer by using innovative nanoparticles which display a high heating potential and are functionalized with a cell internalization and a chemotherapeutic agent to increase cell death.MethodsThe superparamagnetic iron oxide nanoparticles (MF66) were electrostatically functionalized with either Nucant multivalent pseudopeptide (N6L; MF66-N6L), doxorubicin (DOX; MF66-DOX) or both (MF66-N6LDOX). Their cytotoxic potential was assessed in a breast adenocarcinoma cell line MDA-MB-231. Therapeutic efficacy was analyzed on subcutaneous MDA-MB-231 tumor bearing female athymic nude mice.ResultsAll nanoparticle variants showed an excellent heating potential around 500 W/g Fe in the alternating magnetic field (AMF, conditions: H = 15.4 kA/m, f = 435 kHz). We could show a gradual inter- and intracellular release of the ligands, and nanoparticle uptake in cells was increased by the N6L functionalization. MF66-DOX and MF66-N6LDOX in combination with hyperthermia were more cytotoxic to breast cancer cells than the respective free ligands. We observed a substantial tumor growth inhibition (to 40% of the initial tumor volume, complete tumor regression in many cases) after intratumoral injection of the nanoparticles in vivo. The proliferative activity of the remaining tumor tissue was distinctly reduced.ConclusionThe therapeutic effects of breast cancer magnetic hyperthermia could be strongly enhanced by the combination of MF66 functionalized with N6L and DOX and magnetic hyperthermia. Our approach combines two ways of tumor cell killing (magnetic hyperthermia and chemotherapy) and represents a straightforward strategy for translation into the clinical practice when injecting nanoparticles intratumorally.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-015-0576-1) contains supplementary material, which is available to authorized users.

Functionalisation of MSN with mannose for PDT applications dramatically improved the efficiency of PDT on breast cancer cells.

Iron oxide nanoparticles (IONPs) occupy a privileged position among magnetic nanomaterials with potential applications in medicine and biology. They have been widely used in preclinical experiments for imaging contrast enhancement, magnetic resonance, immunoassays, cell tracking, tissue repair, magnetic hyperthermia and drug delivery. Despite these promising results, their successful translation into a clinical setting is strongly dependent upon their physicochemical properties, toxicity and functionalization possibilities. Currently, IONPs-based medical applications are limited to the use of non-functionalized IONPs smaller than 100 nm, with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. However, the main entry of IONPs into the scene of medical application will surely arise from their functionalization possibilities that will provide them with the capacity to target specific cells within the body, and hence to play a role in the development of specific therapies. In this review, we offer an overview of their basic physicochemical design parameters, giving an account of the progress made in their functionalization and current clinical applications. We place special emphasis on past and present clinical trials.

In the present work, we report on the synthesis of cellulose cotton fibers bearing different types of photosensitizers with the aim to prepare new efficient polymeric materials for antimicrobial applications. Anionic, neutral, and cationic amino porphyrins have been covalently grafted on cotton fabric, without previous chemical modification of the cellulosic support, using a 1,3,5-triazine derivative as the linker. The obtained porphyrin-grafted cotton fabrics were characterized by infrared (ATR-FTIR), diffuse reflectance UV-vis (DRUV) spectroscopies, and thermogravimetric analysis (TGA) to confirm the triazine linkage. Antimicrobial activity of porphyrin-cellulose materials was tested under visible light irradiation against Staphylococcus aureus and Escherichia coli . The results showed excellent activity on the Gram-positive bacterium, showing structure-activity relationship, although no photodamage of the Gram-negative microorganism was recorded. A mechanism of bacterial inactivation by photosensitive surfaces is proposed.

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