Photothermal and photodynamic activity of polymeric nanoparticles based on α-tocopheryl succinate-RAFT block copolymers conjugated to IR-780

The aim of this work was the generation of a multifunctional nanopolymeric system that incorporates IR- 780 dye, a near-infrared (NIR) imaging probe that exhibits photothermal and photodynamic properties; and a derivate of α-tocopheryl succinate (α-TOS), a mitochondria-targeted anticancer compound. IR-780 was conjugated to the hydrophilic segment of copolymer PEG-b-polyMTOS, based on poly(ethylene glycol) (PEG) and a methacrylic derivative of α-TOS (MTOS), to generate IR-NP, selfassembled nanoparticles (NPs) in aqueous media which exhibit a hydrophilic shell and a hydrophobic core. During assembly, the hydrophobic core of IR-NP could encapsulate additional IR-780 to generate derived subspecies carrying different amount of probe (IR-NP-eIR).

Evaluation of photo-inducible properties of IR-NP and IR-NP-eIR were thoroughly assessed in vitro. Developed nanotheranostic particles showed distinct fluorescence and photothermal behavior after excitation by a laser light emitting at 808 nm. Treatment of MDA-MB-453 cells with IR-NP or IR-NP-eIR resulted in an efficient internalization of the IR-780 dye, while subsequent NIR-laser irradiation led to a severe decrease in cell viability. Photocytoxicity conducted by IR-NP, which could not be attributed to the generation of lethal hyperthermia, responded to an increase in the levels of intracellular reactive oxygen species (ROS). Therefore, the fluorescence imaging and inducible phototoxicity capabilities of NPs derived from IR-780-PEG-bpolyMTOS copolymer confer high value to these nanotheranostics tools in clinical cancer research.


Evaluation of dental adhesive systems incorporating an antibacterial monomer eugenyl methacrylate (EgMA) for endodontic restorations

The purpose of this study was to incorporate EgMA, an antibacterial monomer into two commercial dental adhesive systems for their application in endodontic restoration with the aim to disinfect the root canal space before curing and to inhibit bacterial growth on their surfaces after being cured.

Almaroof, A., Niazi, S. A., Rojo, L., Mannocci, F. & Deb, S. Evaluation of dental adhesive systems incorporating an antibacterial monomer eugenyl methacrylate (EgMA) for endodontic restorations. Dent Mater 33, e239–e254 (2017). Cite



Polymeric nanoparticles loaded with dexamethasone or α-tocopheryl succinate to prevent cisplatin-induced ototoxicity

The aim of this work is the development of highly protective agents to be administered locally within the middle ear to avoid cisplatin-induced ototoxicity, which affects to 100% of the clinical patients at ultrahigh concentrations (16 mg/kg). The protective agents are based on polymeric nanoparticles loaded with dexamethasone or α-tocopheryl succinate as anti-inflammarory and anti-apoptotic molecules.

Dexamethasone and α-tocopheryl succinate are poorly soluble in water and present severe side effects when systemic administered during long periods of time. Their incorporation in the hydrophobic core of nanoparticles with the appropriate hydrodynamic properties provides the desired effects in vitro (lower cisplatin-induced toxicity, decreasing of caspase 3/7 activity, and lower IL-1b release) and in vivo (reducing the hearing loss at the local level). The local administration of the nanoparticles by bullostomy provides an adequate dose of drug without systemic interference with the chemotherapeutic effect of cisplatin.

Martin-Saldana, S. et al. Otoprotective properties of 6 alpha-methylprednisolone-loaded nanoparticles against cisplatin: In vitro and in vivo correlation. Nanomed.-Nanotechnol. Biol. Med. 12, 965–976 (2016). Cite

Host tissue response by the expression of collagen to cyanoacrylate adhesives used in implant fixation for abdominal hernia repair

The less traumatic use of surgical adhesives rather than sutures for mesh fixation in hernia repair has started to gain popularity because they induce less host tissue damage and provoke less postoperative pain. This study examines the host tissue response to a new cyanoacrylate (CA) adhesive (n-octyl, OCA). Partial defects (3 × 5 cm) created in the rabbit anterior abdominal wall were repaired by mesh fixation using OCA, Glubran2®(n-butyl-CA), Ifabond®(n-hexyl-CA) or sutures. Samples were obtained at 14/90 days for morphology, collagens qRT-PCR/immunofluorescence and biomechanical studies. All meshes were successfully fixed. Seroma was detected mainly in the Glubran group at 14 days. Meshes fixed using all methods showed good host tissue incorporation. No signs of degradation of any of the adhesives were observed. At 14 days, collagen 1 and 3 mRNA expression levels were greater in the suture and OCA groups, and lower in Ifabond, with levels varying significantly in the latter group with respect to the others. By 90 days, expression levels had fallen in all groups, except for collagen 3 mRNA in Ifabond. Collagen I and III protein expression was marked in the suture and OCA groups at 90 days, but lower in Ifabond at both time points. Tensile strengths were similar across groups. Our findings indicate the similar behavior of the adhesives to sutures in terms of good tissue incorporation of the meshes and optimal repair zone strength. The lower seroma rate and similar collagenization to controls induced by OCA suggests its improved behavior over the other two glues.

Pascual, G., Rodríguez, M., Pérez-Köhler, B. et al. J Mater Sci: Mater Med (2017) 28: 58. doi:10.1007/s10856-017-5869-8

Bioassay of cyanoacrylate tissue adhesives used for intraperitoneal mesh fixation

This study examines the intraperitoneal behavior of two cyanoacrylate tissue adhesives: Ifabond® and a new, non-marketed octyl cyanoacrylate adhesive (OCA) used for the intraperitoneal fixation of a laminar expanded polytetrafluoroethylene (ePTFE) mesh.

Bellón JM, Fernández-Gutiérrez M, Rodríguez M, Sotomayor S, Pérez-Köhler B, Kuhnhardt A, Pascual G, San Román J. 2017. Bioassay of cyanoacrylate tissue adhesives used for intraperitoneal mesh fixation. J Biomed Mater Res Part B 2017:105B:312–319

Strontium folate loaded biohybrid scaffolds seeded with dental pulp stem cells induce in vivo bone regeneration in critical sized defects

Strontium folate (SrFO) is a recently developed bone promoting agent with interest in medical and pharmaceutical fields due to its improved features in comparison to current strontium based therapies for osteoporosis and other bone diseases. In this work SrFO derivative was synthesized and loaded into biohybrid scaffolds obtained through lyophilisation of semi-interpenetrating networks of chitosan polyethylene glycol dimethacrylate and beta tri-calcium phosphate (βTCP) fabricated using free radical polymerization. The scaffolds were seeded with pluripotent stem cells obtained from human dental pulp and their potential to regenerate bone tissues were assessed using a critical sized defect model of calvaria in rats and compared with those obtained without SrFO. The results obtained both in vitro and in vivo demonstrated excellent cyto-compatibility with resorption of scaffolds in 4–6 weeks and a total regeneration of the defect, with a more rapid and dense bone formation in the group with SrFO. Thus, the use of stem cells sourced from human dental pulp in combination with SrFO are very promising systems for their application in compromised osseous tissue regeneration.

Julio San Román del Barrio received the condition of Doctor Honoris Causa in Chemistry at the University of La Habana

p1500308Julio San Román del Barrio, received the condition of Doctor Honoris Causa in Chemistry at the University of La Habana (UH).

Proposed by the Center for Biomaterials (Biomat) on its 25th anniversary, UH gave the title to the academic, for his contributions to the development of this area, especially in the field of polymeric materials with pharmacological applications in surgery or engineering tissue, and scientific and academic contribution in the country.

The ceremony was attended by Miguel Jorge Llivina Lavigne, representative of the Regional Office of Culture for Latin America and the Caribbean of the United Nations Educational, Scientific and Cultural Organization (UNESCO), and Mayda Goite Pierre, rector of the University of Havana.

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