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Microneedles: Current Trends and Applications
Published in Tuhin S. Santra, Microfluidics and Bio-MEMS, 2020
Hima Manoj, Pallavi Gupta, Loganathan Mohan, Moeto Nagai, Syrpailyne Wankhar, Tuhin S. Santra
Prausnitz and coworkers developed a layer-by-layer deposition technique for polyelectrolytes to coat stainless-steel microneedles with bovine pancreatic ribonuclease A. The protein release took place by the hydrolytic degradation of the coating layer after microneedle insertion up to a depth of 500 μm in porcine cadaver skin [155]. Recently, conserved human melanoma antigen– reinforced, polyelectrolyte multilayer (PEM)-assembled microneedles were developed. These can act as a platform for assembling cancer vaccine components on microneedle arrays for intradermal delivery from these substrates [156]. Later, Martin et al. assessed a low-temperature vacuum-forming method that demonstrates the fabrication of microneedles from a dehydrated sugar mixture of trehalose anhydrous, trehalose dihydrate, sucrose, and maltose [71]. Rats were used as the model for assessing the feasibility of dextran microneedle preparation by a polypropylene thread. The study shows that the recombinant human growth hormone (rhGH) levels in rat plasma shoot to the peak after 1 h of microneedle administration. The rhGH levels were found to be equivalent to that after intravenously injected rhGH solution [157].
Advances in Preparations and Applications of Polymeric Microsphers
Published in Kunio Esumi, Polymer Interfaces and Emulsions, 2020
The first example is the refolding of protein using thiol-carrying microspheres, as studied by Fujimoto et al. [114]. They found that the microsphere could be used as a template to obtain the functional three-dimensional structures from denatured (not aggregated) polypeptide chains. They used the microsphere composed of a PST core and a poly(glycidyl methacrylate) (PGMA) surface layer, on which thiol groups were immobilized by coupling dithiothreitol with epoxy groups. Scrambled ribonuclease A (RNaseA) carrying incorrect disulfide pairings was chosen as a model protein for refolding. They found that the refolding was accelerated by the microspheres with thiol groups, although renaturation was not observed in the presence of unmodified microspheres without thiol group. Possibly, thiol groups on microspheres surface can preferentially attack disulfide bonds in the scrambled RNaseA. This attack can trigger protein refolding through thiol–disulfide exchange reactions at the microsphere–protein interface. Furthermore, they found that the scrambled RNaseA was bound on modified microspheres having refolding activity, whereas the native RNaseA was hardly adsorbed onto them. The extent of renaturation increased with incubation time, whereas the scrambled RNaseA adsorption showed a slight increase. This suggests that adsorption of misfolded protein and desorption of the refolded protein simultaneously proceed in this system.
Applications of Environmental Biotechnology to Bioremediation
Published in Donald L. Wise, Debra J. Trantolo, Remediation of Hazardous Waste Contaminated Soils, 2018
John Sanseverino, James T. Fleming, Armin Heitzer, Bruce M. Applegate, Gary S. Sayler
Another RNA detection method that is very sensitive and allows for quantitation of mRNA is the ribonuclease protection assay (RPA). This procedure involves solution hybridization of the total extracted RNA of a sample with an in vitro synthesized RNA probe that is complementary to the target RNA molecule, conventionally referred to as an anti-sense RNA probe. After hybridization, the RNA–RNA hybrid is subjected to ribonuclease digestion, which specifically degrades any single-stranded RNA that is not identically complementary and thus hybridized to the anti-sense probe. After ribonuclease treatment the protected double-stranded RNA fragment is electrophoresed on a gel and may be quantified by comparison to protected fragments created by hybridizing known amounts of in vitro synthesized sense-strand RNA with the anti-sense probe. This is accomplished relatively easily if the RNA transcription vector described previously has two different RNA polymerase promoters on either side of the inserted sequence; an anti-sense transcript used for the labeled probe may be generated from one promoter, and the sense transcript generated from the other promoter is used to make the standard curve. The RPA procedure has a reported sensitivity to 0.1 pg of mRNA,36 permits direct absolute quantification, and is suitable for the screening of multiple samples.
Enhanced anticancer potency by thermo/pH-responsive PCL-based magnetic nanoparticles
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Samad Hosseini Sadr, Soodabeh Davaran, Effat Alizadeh, Roya Salehi, Ali Ramazani
The effect of DOX-MTX-loaded composite on cell cycle progression was implemented by flow cytometry analysis. In brief, about 1 × 105 MCF-7 cells were transferred in six well plates. Next day, the MCF-7 cells were treated with free DOX-MTX or DOX@MTX loaded Fe3O4@PCL grafted-poly (HEMA-co-MAA-co-NIPAAm-co-TMSPM) nanocomposites for a time period of 48 h. Subsequently, the cells were harvested and fixed with ice cold ethanol in refrigerator for 48 h. Afterward, the RNA molecules were removed with Ribonuclease A (Sinaclon). Finally, the cells were stained with Propidium Iodide (Sigma) in dark place. The DNA content was measured using Flowcytometry system (Beckton Dikinson).