Using carbon nanotubes to deliver genes to hard-to-transfect mammalian primary fibroblast cells

Abstract

The insertion of DNA into primary mammalian cells is an important step towards gene therapy and production of transgenic animals. Recently, carbon nanotubes have been explored as an efficient novel non-viral system for delivering genes to cells due to their unique structure and properties. However, their potential for transfecting primary bovine cells in non-toxic concentrations has not been tested. The purpose of this study was to evaluate the cytotoxicity of carboxylic acid-functionalized multiwalled carbon nanotubes (COOH-MWCNTs) and their use to deliver plasmid DNA encoding the gene of green fluorescent protein to bovine primary fibroblast cells. Flow-cytometry cell viability results have shown the non-toxic nature of COOH-MWCNTs at low concentrations. The frequency shifts in Raman spectroscopy showed that the plasmid DNA connects to the nanomaterial. Fluorescence imaging, flow-cytometry and PCR analysis confirmed that the COOH-MWCNT nanovectors delivered pDNA into primary fibroblast cells successfully. The results show that COOH-MWCNTs can be attractive alternatives for delivery of DNA into hard-to-transfect primary bovine cells.

Tuning the Surface Chemistry of Second-Harmonic-Active Lithium Niobate Nanoprobes Using a Silanol–Alcohol Condensation Reaction

“…This process was repeated two more times to remove unreacted 12-HDA molecules from the NPs. The −COOH groups have two characteristic Raman bands between 1400 and 1700 cm –1 due to symmetric and asymmetric stretching vibrations of the carbonyl groups, respectively. − Two characteristic Raman bands at ∼1480 and ∼1600 cm –1 were observed for the purified NPs modified with 12-HDA, which were absent in both the pristine NPs and the SiO x -coated NPs (Figure ). The presence of these Raman bands indicated that the core–shell NPs were functionalized with 12-HDA. , Coupling these −COOH functional groups to other molecules through an amide bond formation would improve the utility of these NPs but would also provide a means of verifying the anchoring of 12-HDA to the SiO x surfaces through the formation of a silyl ether bond and the availability of the −COOH groups as new reactive sites on the NPs.…”

“…The presence of these Raman bands indicated that the core−shell NPs were functionalized with 12-HDA. 60,62 Coupling these −COOH functional groups to other molecules through an amide bond formation would improve the utility of these NPs but would also provide a means of verifying the anchoring of 12-HDA to the SiO x surfaces through the formation of a silyl ether bond and the availability of the −COOH groups as new reactive sites on the NPs.…”

“…Lithium niobate was selected as the core material in this study due to its utility in SHG-based bioimaging. ,, Lithium niobate, a non-centrosymmetric material, is one of the most widely explored nonlinear optical (NLO) materials due to its excellent SHG response. , SHG is a second-order NLO process in which two incident photons of a fundamental frequency (ω) are converted into a single photon having double the initial frequency (2ω). , Unlike fluorescent probes, the SHG probes have a stable, non-blinking signal that does not saturate with increasing excitation power, and their emission wavelength can be widely tuned by adjusting the excitation wavelength. ,,, The processes associated with the SHG response are on the femtosecond time scale, which is 4 to 5 orders of magnitude faster than the nanosecond response time of typical fluorophores. − These properties enable SHG probes to be used in the study of thick samples, such as deep-tissue imaging. ,− ,, The SHG nanoprobes also enable long-term (e.g., months) monitoring and tracking of biological processes in whole organisms and tissues. ,− ,, Although SHG probes based on LiNbO 3 NPs have several advantages over fluorescent molecules, further development of SHG probes for bioimaging will require methods to tune their surface chemistry. For example, functionalizing the surfaces of these nanoprobes with biologically relevant molecules will be essential to improve their colloidal stability and to enable multimodal tracking and validation of their location within biological systems.…”

Biochar from Andropogon grass (Andropogon gayanus cv. Planaltina) applications in dye removal by adsorption and slow filtration

“…The biomaterial was analyzed using Raman and Infrared vibrational spectroscopic methods to characterize its chemical structure. Figure 1 shows the Raman spectrum of biochar and it is possible to observe two characteristic bands of carbonic material, one at 1272 cm -1 (D band) and the other at 1592 cm -1 (G band) (Cuesta et al, 1994;Sheng, 2007;Munk et al, 2017). Both reveal the presence of sp 2 -type hybridization carbon atoms in benzene or partially hydrogenated condensed benzene rings (Fuertes et al, 2010).…”

“…The effective diameter being defined as the opening of the sieve that allows the accumulated passage of 10% of the analyzed sample. And the uniformity coefficient is the porosity of the sieve that retains 40% of the sample divided by the effective diameter (Bourke et al, 1995;Sheng, 2007;Munk et al, 2017) The test was carried out on a laboratory scale, in a descending filter containing the charcoal produced by the pyrolysis of Andropogon grass as a filtering medium. The experiment was carried out in continuous flow, using the methylene blue solution at a concentration of 20.01 mgL -1 at pH 7.0.…”