1.Luminescent Nanocellulose Platform: From Controlled Graft Block Copolymerization to Biomarker Sensing.
Navarro JR1, Wennmalm S2, Godfrey J1, Breitholtz M3, Edlund U1. Biomacromolecules. 2016 Mar 14;17(3):1101-9. doi: 10.1021/acs.biomac.5b01716. Epub 2016 Jan 29.
A strategy is devised for the conversion of cellulose nanofibrils (CNF) into fluorescently labeled probes involving the synthesis of CNF-based macroinitiators that initiate radical polymerization of methyl acrylate and acrylic acid N-hydroxysuccinimide ester producing a graft block copolymer modified CNF. Finally, a luminescent probe (Lucifer yellow derivative) was labeled onto the modified CNF through an amidation reaction. The surface modification steps were verified with solid-state (13)C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy. Fluorescence correlation spectroscopy (FCS) confirmed the successful labeling of the CNF; the CNF have a hydrodynamic radius of about 700 nm with an average number of dye molecules per fibril of at least 6600. The modified CNF was also imaged with confocal laser scanning microscopy. Luminescent CNF proved to be viable biomarkers and allow for fluorescence-based optical detection of CNF uptake and distribution in organisms such as crustaceans.
2.Fabrication of homobifunctional crosslinker stabilized collagen for biomedical application.
Lakra R1, Kiran MS, Sai KP. Biomed Mater. 2015 Nov 27;10(6):065015. doi: 10.1088/1748-6041/10/6/065015.
Collagen biopolymer has found widespread application in the field of tissue engineering owing to its excellent tissue compatibility and negligible immunogenicity. Mechanical strength and enzymatic degradation of the collagen necessitates the physical and chemical strength enhancement. One such attempt deals with the understanding of crosslinking behaviour of EGS (ethylene glycol-bis (succinic acid N-hydroxysuccinimide ester)) with collagen to improve the physico-chemical properties. The incorporation of a crosslinker during fibril formation enhanced the thermal and mechanical stability of collagen. EGS crosslinked collagen films exhibited higher denaturation temperature (T d) and the residue left after thermogravimetric analysis was about 16 ± 5.2%. Mechanical properties determined by uniaxial tensile tests showed a threefold increase in tensile strength and Young's modulus at higher concentration (100 μM). Water uptake capacity reduced up to a moderate extent upon crosslinking which is essential for the transport of nutrients to the cells.
3.A functionalized, injectable hydrogel for localized drug delivery with tunable thermosensitivity: synthesis and characterization of physical and toxicological properties.
Elias PZ1, Liu GW1, Wei H1, Jensen MC2, Horner PJ3, Pun SH4. J Control Release. 2015 Jun 28;208:76-84. doi: 10.1016/j.jconrel.2015.03.003. Epub 2015 Mar 4.
Thermosensitive injectable hydrogels have been used for the delivery of pharmacological and cellular therapies in a variety of soft tissue applications. A promising class of synthetic, injectable hydrogels based upon oligo(ethylene glycol) methacrylate (OEGMA) monomers has been previously reported, but these polymers lack reactive groups for covalent attachment of therapeutic molecules. In this work, thermosensitive, amine-reactive and amine-functionalized polymers were developed by incorporation of methacrylic acid N-hydroxysuccinimide ester or 2-aminoethyl methacrylate into OEGMA-based polymers. A model therapeutic peptide, bivalirudin, was conjugated to the amine-reactive hydrogel to investigate effects on the polymer thermosensitivity and gelation properties. The ability to tune the thermosensitivity of the polymer in order to compensate for peptide hydrophilicity and maintain gelation capability below physiological temperature was demonstrated.
4.Comparison of impedimetric detection of DNA hybridization on the various biosensors based on modified glassy carbon electrodes with PANHS and nanomaterials of RGO and MWCNTs.
Benvidi A1, Tezerjani MD2, Jahanbani S2, Mazloum Ardakani M2, Moshtaghioun SM3. Talanta. 2016 Jan 15;147:621-7. doi: 10.1016/j.talanta.2015.10.043. Epub 2015 Oct 17.
In this research, we have developed lable free DNA biosensors based on modified glassy carbon electrodes (GCE) with reduced graphene oxide (RGO) and carbon nanotubes (MWCNTs) for detection of DNA sequences. This paper compares the detection of BRCA1 5382insC mutation using independent glassy carbon electrodes (GCE) modified with RGO and MWCNTs. A probe (BRCA1 5382insC mutation detection (ssDNA)) was then immobilized on the modified electrodes for a specific time. The immobilization of the probe and its hybridization with the target DNA (Complementary DNA) were performed under optimum conditions using different electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The proposed biosensors were used for determination of complementary DNA sequences. The non-modified DNA biosensor (1-pyrenebutyric acid-N- hydroxysuccinimide ester (PANHS)/GCE), revealed a linear relationship between ∆Rct and logarithm of the complementary target DNA concentration ranging from 1.
