Efficient PFAS Removal by Amine-Functionalized Sorbents: Critical Review of the Current Literature

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of persistent and mobile fluoro-organic chemicals that have been detected in many water supplies, and their recommended safe concentrations in drinking water are as low as 6 ng/L. Current technological advances suggest that amine-containing sorbents can provide alternative solutions to PFAS control in the treatment of municipal water and wastewater at relatively low PFAS concentrations. The objective of this review is to provide critical analysis of the development and application of amine-containing sorbents for PFAS removal. The removal of PFAS by aminated sorbents relies on the combined effects of three main factors: (i) electrostatic interactions with functional groups of the sorbent, (ii) hydrophobic interactions with the sorbent and between PFAS molecules, and (iii) sorbent morphology. The design of next-generation sorbents should take into consideration these three factors and their relative contribution. We also provide an outlook and highlight of the key areas of innovative research needs to develop more efficient sorbents that will enable compliance with the increasingly stringent regulations of PFAS

The synthesis and self-assembly studies of two bioactive BMP-7 short peptides modified rosette nanotubes for bone tissue engineering

Bone fractures are one of the most common bone complications. In more severe cases, bone fixation is accomplished using titanium (Ti) implant materials. Unfortunately, the need for revision surgery often arises due to implant loosening and/or deterioration of the implant/bone interface. Rosette nanotubes (RNTs) are a class of self-assembled organic materials obtained through the self-assembly of a guanine-cytosine hybrid base (G 27C motif). These organic materials have been found to increase osteoblast (bone forming cells) adhesion and hydroxyapatite deposition (bone regeneration) on titanium implants as well as on engineered hydrogels. In order to increase the bioactivity of RNTs to enhance bone cell function on Ti implants, two RNT motifs functionalized with different bioactive deca-peptides (A, B) chosen from the knuckle region of bone morphogenic proteins-7 (BMP-7) were synthesized. Their self-assembly process was investigated in water using UV-Vis and SEM techniques. \ua9 2011 Materials Research Society.Peer reviewed: YesNRC publication: Ye

Towards radiolabeled G 27C module for cellular imaging of bioactive Rosette nanotubes

Rosette nanotubes (RNTs) are obtained through the self-organization of biologically inspired self-complementary guanine-cytosine modules (G 27C motif) under physiological conditions. These architectures can express bioactive molecules on their surface by functionalizing the G 27C motif prior to self-assembly. As a result, RNTs are promising drug delivery vehicles for the treatment of diseases such as cancer and inflammatory disorders. Towards these studies, we have explored the toxicity and immunological response of RNTs and are now focused on understanding their cellular uptake, biological distribution and kinetics in vivo. For these investigations, we need to construct a RNT labeled with a radionuclide that can be followed in vivo by SPECT (single photon emission computed tomography) imaging. In this proceeding, we describe a twin G 27C motif that is functionalized with mercaptoacetyl triglycine (MAG 3). This is a well known ligand which is able to form a stable chelate with the radionuclides 99mTc or 186/188Re. In order to develop the chemistry for this radiolabeling strategy for the RNTs, we demonstrate the chelation of the MAG 3 functionalized twin-G 27C motif with cold rhenium and investigate the self-assembly properties of the complex into RNTs under aqueous conditions. \ua9 2011 Materials Research Society.Peer reviewed: YesNRC publication: Ye

Synthesis of a Tetracyclic G∧C Scaffold for the Assembly of Rosette Nanotubes with 1.7 nm Inner Diameter

The synthesis of a tetracyclic self-complementary molecule 4 for self-assembly into rosette nanotubes is presented. This new heterocycle has a core structure containing two pyrido[2,3-d]pyrimidine molecules fused together and features the Watson−Crick hydrogen bond donor−acceptor arrays of both guanine (G) and cytosine (C). Current methods to synthesize pyrido[2,3-d]pyrimidines require harsh conditions and long reaction times and result usually in low product yields. This is particularly problematic for the direct incorporation of functional groups that cannot withstand these conditions. Here, we present an efficient approach to access the multifunctional pyrido[2,3-d]pyrimidine intermediate 2 under relatively mild conditions using three regioselective SNAr reactions at C2, C4, and C7 on the trichloro compound 1. The electron-withdrawing group and amino functionalities on 2 are then used as a handle to install the third and fourth rings of 4 using a Friedländer-type condensation followed by mixed urea synthesis and cyclization