Versatile Covalent Postsynthetic Modification of Metal Organic Frameworks via Thermal Condensation for Fluoride Sensing in Waters.

Having access to safe drinking water is one of the 17 sustainable development goals defined by the United Nations (UN). However, many settlements around the globe have limited access to drinkable water due to non-anthropogenic pollution of the water sources. One of those pollutants is fluoride, which can induce major health problems. In this manuscript, we report on a post synthetic functionalization of metal organic frameworks for the sensing of fluoride in water. The proposed thermal condensation methodology allows for a high yield of functionalization using few steps, reducing reagent costs and generating minimal by-products. We identified a Rhodamine B functionalized Al-BDC-NH2 metal organic framework as one particularly suitable for fluoride detection in water.

The Long and Bright Path of a Lanthanide MOF: From Basics towards the Application.

The development of portable, reliable, and low-cost sensors for assessing the quality of natural water sources is of high relevance in developing countries as they can serve as an intermediate solution prior to the building of permanent potable water distribution infrastructure. These sensors should be simple to operate by non-trained operators and easy to manufacture locally. Lanthanide-based metal-organic frameworks (MOFs) offer a trustable platform due to their intense emission in regions of the visible spectra and their high sensitivity to fluorides in water. Cotton was chosen as a substrate due to its high hydrophilicity which, together with the highly porous nature of the MOF, allows for shorter reaction times. The modified cotton was characterized by XRD, SEM as well as XAFS, hence probing the presence of [Tb(BTC)6 (H2 O)] (Tb-BTC) attachment to cotton. Changes in the emission when Tb-BTC modified cotton was exposed to water and aqueous fluoride solutions were monitored as a function of time. Crystalline phase changes were identified that correlated to structural information. Finally, the Tb-BTC modified cotton was used to build a fluoride demonstrator sensor with a linear response of up to 10 mg L-1 and a limit of detection of 0.8 mg L-1 , making it suitable for drinking water analysis under international regulations.

Soybean agglutinin-conjugated silver nanoparticles nanocarriers in the treatment of breast cancer cells.

Silver nanoparticles (AgNPs) induce diverse cell-death mechanisms, similar to those promoted by anticancer chemotherapeutics; however, they have not been tested in vivo because their action is not limited to cancer cells. Therefore, in vivo evaluations of their effectiveness should be developed with targeting systems. Breast cancer shows changes in the sugar expression patterns on cell surfaces, related to cancer progression and metastases; those changes have been identified previously by the specific binding of soybean agglutinin (SBA). Here is proposed the use of SBA to target the AgNP activity in breast cancer. For that, the present work reports the synthesis of AgNPs (3.89 ± 0.90 nm) through the polyol method, the generation of AgNP nanocarriers, and the bioconjugation protocol of the nanocarrier with SBA. The free AgNPs, the AgNP nanocarriers, and the SBA-bioconjugated AgNP nanocarriers were tested for cytotoxicity in breast cancerous (MDA-MB-231and MCF7) and non cancerous (MCF 10A) cells, using the MTT assay. AgNPs demonstrated cytotoxic activity in vitro, the non cancerous cells (MCF 10A) being more sensible than the cancerous cells (MDA-MB-231 and MCF7) showing LD(50) values of 128, 205, and 319 µM Ag, respectively; the nanoencapsulation decreased the cytotoxic effect of AgNPs in non cancerous cells, maintaining or increasing the effect on the cancer-derived cells, whereas the SBA-bioconjugation allowed AgNP cytotoxic activity with a similar behavior to the nanocarriers. Future experiments need to be developed to evaluate the targeting effect of the SBA-bioconjugated AgNP nanocarriers to study their functionality in vivo.

Grafting collagen on poly (lactic acid) by a simple route to produce electrospun scaffolds, and their cell adhesion evaluation.

Increasing bioactivity and mechanical properties of polymers to produce more suitable scaffold for tissue engineering is a recurrent goal in the development of new biomedical materials. In this study, collagen-functionalized poly (lactic acid), PLA, was obtained by means of a simple grafting route, and electrospun scaffolds were produced to grow cells in vitro; their bioactivity was compared with scaffolds made of physical blends of PLA and collagen. Grafting was verified via nuclear magnetic resonance, attenuated total reflection-Fourier transform infrared and X-ray photoelectron spectroscopy. The cell adhesion performance of the scaffolds was studied using macrophages. Elastic modulus (74.7 megapascals) and tensile strength (3.0 megapascals) of the scaffold made from PLA grafted with collagen were substantially higher than the scaffolds made from physical blends of collagen and PLA: 32 and 2.16 megapascals, respectively, implying a more resistant material because of the chemical bond of the polypeptide to PLA. Besides, the fibers had more uniform diameter without defects. Scaffolds made from PLA grafted with collagen presented four-fold increase in cell adhesion than those of PLA blended with collagen. Furthermore, cell spreading within the scaffolds occurred only when collagen-functionalized poly (lactic acid) was used. These results open a new option for the easy tailoring of nanofiber-based scaffolds in three dimensions for tissue engineering.