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Detonation nanodiamonds (DNDs) are usually small particles of 4–5 nm, but in aqueous suspension, DNDs form agglomerates in sizes larger than 1 μm. We propose the use of Bead Assisted Sonic Disintegration and a carboxylation procedure, to reduce DNDs aggregates sizes to approximately 100 nm. High cost zirconium beads have been substituted by silica beads synthetized in our laboratory and less-time consuming conditions were standardized. Techniques as Dynamic Light Scattering (DLS), Fourier Transform InfraRed Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS), have been used to characterize the resulting diamond nanoparticles. While the incubation of Red Blood Cells with partially disaggregated DNDs was used to study whether these nanodiamonds impact in a living system. Our results show the absence of a negative effect in cell viability as well as no differences between Raman spectra of hemoglobin (Hb), from control and cell + DNDs conditions.

Using detonation nanodiamonds and fluorescent nitrogen-vacancy center nanodiamonds, linked to gold nanoparticles, we synthesized two hybrid nanostructures (HGDs) that were subsequently conjugated with a fluorophore. An amplification effect induced by the gold nanoparticles increased the emission spectrum of the fluorophore, maximizing the possibilities for imaging applications of these HGDs. The incubation of the nanostructures with HeLa cells produced no alteration of cell viability after 3 h and showed the presence of nanostructures in the cell cytoplasm at 24 h. These observations also indicate the potential biomedical use of the proposed HGDs.

Nanodiamonds (NDs) possess exceptional physical, chemical, and biological properties, which make them suitable for potential biomedical applications. They are biocompatible and their usefulness as effective Raman/fluorescence probes for labeling as well as for drug delivery has been demonstrated. Related to their biocompatibility, the interaction between NDs and red blood cells (RBCs) is of great interest. In this work, the influence of carboxylated NDs (cNDs) in the re-oxygenation capability of both γ-irradiated and stored RBCs was studied. The standard 25 Gy γ dose recommended to prevent transfusion associated graft-versus-host disease was used. A 5-day maximum storage time was used to evaluate the “storage lesion.” The hemoglobin (Hb) oxygenation state was assessed by Raman microspectroscopy and the morphologic changes on cells were tracked by optical imaging. Our results show that irradiated RBCs have a better re-oxygenation capability and morphological recovery when they are in presence of cNDs.

The use of nanodiamonds in studies with living systems generally involves the modification of their surfaces with functional groups. Fluorescent molecules can be attached to these groups, so that one can know the exact position of the particles in each moment of the interaction with the cells. Here we modify the surface of detonation nanodiamonds and nitrogen-vacancy center nanodiamonds using carboxylation and hydroxylation procedures. Subsequent reactions with silicates and cysteine, before addition of fluorescein allow to obtain fluorescent nano-conjugates. We used confocal microscopy to observe the position of nanodiamonds interacting with HeLa cells. At 3 h post-incubation the green fluorescence is localized in extracellular rounded like-vesicles assemblies while at 24 h the conjugates can be observed inside the cells. The measurement of the fluorescence emitted by both conjugates allowed to find an enhanced emission of fluorescein isothiocyanate (FITC) when the nitrogen-vacancy center is present. We propose the existence of a fluorescence enhancement by electron transference process. The procedure described in this work allows the functionalization of nanodiamonds with FITC and other molecules using functional surface groups and small size mediators. Also, as was proved in our work, the nanodiamond-fluorescein conjugates can be used to track nanoparticles position within the cell. Localization studies are particularly important for drug delivery applications of nanodiamonds.

Water radiolysis involves chemical decomposition of the water molecule into free radicals after exposure to ionizing radiation. These free radicals have deleterious effects on normal cell physiology. Carboxylated nanodiamonds (cNDs) appear to modulate the deleterious effects of γ-irradiation on the pathophysiology of red blood cells (RBCs). In the present work, the antioxidant activity of hydrated cNDs (h-cNDs) on limiting oxidative damage (the water radiolysis effect) by γ-irradiation was confirmed. Our results show that h-cNDs have remarkable free radical scavenging ability and preserve the enzymatic activity of catalase after γ-irradiation. The underlying mechanism through which nanodiamonds exhibit antioxidant activity appears to depend on their colloidal stability. This property of detonation synthesized nanodiamonds is improved after carboxylation, which in turn influences changes in the hydrogen bond strength in water. The observed stability of h-cNDs in water and their antioxidant activity correlates with their protective effect on RBCs against γ-irradiation.

Escherichia coli ( E. coli ) that expresses galactose-reactive lectins, like K88 adhesin, causes high mortality among piglets. Carbohydrates that compete for adhesion could serve as an alternative for disease prevention. Porcine serum albumin (PSA) was modified by non-enzymatic glycation with lactose to produce PSA-Lac or PSA-Glc β (1–4) Gal, as confirmed by reduction of available free amino groups, increased molecular mass and by Ricinus communis lectin recognition. E. coli K88 binds to PSA-Lac treatments containing three and four lactoses, respectively. In addition, PSA-Lac partially inhibited K88 strain adherence to mucins. These results suggest that neoglycoconjugates obtained by non-enzymatic glycation of proteins may serve in the prophylaxis of piglets’ diarrhea.

La sangre animal es una excelente fuente de proteínas, que al desecharse causa problemas de contaminación. La proteína mayoritaria del suero porcino es l albúmina (PSA, por sus siglas en inglés), la cual tiene un gran potencial biotecnológico para utilizarse en la industria pecuaria y alimentaria. Estos cambios pueden afectar tanto fas propiedades funcionales de la proteína, como su función biológica. Una manera práctica y sencilla de conjugar a la PSA con oligosacáridos es a través de la reacción química de Maillard. Para ello se evaluaron dos métodos de glicación de PSA con lactosa en fase sólida. El primero, de Boratynski, consistió en glicar a tiempo constante (30 min) y a diferentes temperaturas de reacción (60, 80, 100 y 120 ºC). En el segundo, el de Fenaille, se usó temperatura constante (60 ºC) variando el tiempo de calentamiento (4, 6 y 8 h). Con la conjugación de lactosa; se esperaba establecer interacciones de biorreconocimiento con lectinas y con adhesinas microbianas. Los productos de lactosilación de la PSA (PSA-gluc β(1-4)gal), al cual llamaremos PSA-Lac, se caracterizaron midiendo los cambios de masa (SDSPAGE y espectroscopía de masas), de fluorescencia intrínseca del triptófano, de disponibilidad de grupos aminos y de solubilidad. Así mismo, se determinó el reconocimiento biológico de la PSA-Lac usando a la lectina de Ricinus communis (RCAJ y a la adhesina de Escherichia coli K88+ (E. coli K88+). Esto con el fin de explorar la posibilidad de utilizar los neoglicanos producidos en la prevención de diarreas en cerdos. Los resultados obtenidos con las PSA-Lac sintetizadas a partir del método de Boratynski fueron los siguientes, el grado de glicación fue proporcional a la temperatura utilizada. La espectroscopía de masas indicó la presencia de 38 y 41 lactosas para los tratamientos glicados a 100 y 120 ºC respectivamente. La lectina de Ricinus communis reconoció a todos los neoglicanos de PSA-Lac y la intensidad del reconocimíento fue proporcional a la temperatura de reacción. Únicamente la PSA-Lac obtenida a 100 ºC fue reconocida por la adhesina de E. coli K88+.