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Process Affinity Chromatography
Published in Juan A. Asenjo, Separation Processes in Biotechnology, 2020
Turning now to the synthetic macroporous beaded matrices, some deserve particular mention. Fractogel TSK (Merck, West Germany), which is identical to Toyopearl (Toyo Soda, Japan), is a hydrophilic vinyl polymer with free hydroxyl groups and is available in different porosities. Trisacryl GF2000LS (IBF, France) is obtained by copolymerization of a new monomer, N-acryloyl-2-amino-2-hydroxymethyl-1, 3-propane-diol, and a bifunctinal monomer. The functional groups that constitute this gel are nonionic, hydrophilic (three hydroxymethyls and one secondary amine), and compatible with biological molecules (Fig. 4). Separon H1000 is made by copolymerization of hydroxyalkyl methacrylate and alkylene dimethacrylate. This process yields heavily cross-linked microparticles, which by aggregation give rise to macroporous beads. All the supports above are macroporous, stable in a wide pH range as well as in most organic solvents and deforming agents, and are autoclavable. To conclude the synthetic supports, we should mention Eupergit C and the high-performance version, Eupergit C30N (Röhm Pharma, FRG). The primary structure of this polymer consists of methacrylamide, N-methylenebis-methacrylamide, glycidyl methacrylate, and/or allyl glycidyl ether. The oxirane groups present are useful for direct ligand immobilization. Although this support is macroporous and has excellent chemical and physical stability, it is possible that it may give some nonspecific adsorption even after hydrolysis of its reactive groups (Krämer, 1981; Clonis, 1987b).
Recent Developments in Transdermal Drug Delivery Systems Based on an Electrospun Nanofibrous Scaffold
Published in Mangala Joshi, Nanotechnology in Textiles, 2020
Metallic nanoparticles have been incorporated into electrospun fiber scaffolds to inhibit bacterial growth. Thomas et al. loaded silver nanoparticles (Ag NPs) into a PCL electrospun fibrous mat and studied its antimicrobial activity against Staphylococcus haemolyticus and Staphylococcus epidermidis [26]. Dashdorj et al. also showed antimicrobial activity of Ag NP-loaded zein (a protein from corn) electrospun nanofibers against E. coli and S. aureus [27]. Similarly, GhavamiNejad et al. prepared poly(dopamine methacrylamide co methyl methacrylate) (MADO) electrospun nanofibers loaded with Ag NPs and evaluated the antimicrobial efficacy of the scaffold against S. aureus, E. coli, and P. aeruginosa [28]. They observed that almost 13% of Ag was released within day 1 but the release was slower for the next 6 days. In vivo efficacy of the Ag NP–MADO scaffold was examined on a rat wound healing model for 15 days and significantly higher wound healing (92%) was observed while comparing with both controls (51%) and native MADO fiber mats (65%). Woo et al. designed a bilayered scaffold for wound healing application where the upper layer consists of chitosan electrospun nanofibers loaded with TiO2 and the lower one comprises an extracellular matrix derived from human adipose cells [29]. The bilayered scaffold not only showed antimicrobial activity against S. aureus and E. coli but also reduced bacterial penetration into the wound bed.
Silica Nanoparticles for Drug Delivery
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Lu and co-workers took octadecyl-functionalized hollow MSN and applied a coating of the amphiphilic block copolymer of [7-(didodecylamino(coumarin-4-yl] methyl methacrylate with hydroxyethylacrylate and N-(3-aminopropyl) methacrylamide hydrochloride. The polymer was functionalized with folic acid, which targeted folate receptor expressing cancer cells, and served a dual purpose: tracking the particles via the coumarin moiety fluorescence and removable capping of the hollow MSN mesopores which prevented premature drug leakage. Upon excitation by a femtosecond NIR light laser, the polymer degrades via a two-photon absorption process also arising from the coumarin moiety. Doxorubicin was loaded into the hollow core and negligible release was observed in the dark. Upon exposure to NIR light, ~60% of the loaded DOX was released into PBS at 37°C and, in experiments with KB cells, cell viability decreased dramatically when incubated with DOX-loaded hollow MSN and exposed to NIR light. This is more notable when the high cell viability of non-DOX-loaded hollow MSN irradiated with NIR light and DOX-loaded hollow MSN in the dark. It was also observed that the folic acid functionalized particles were internalized into folic acid receptor expressing KB cells vs. almost no endocytosis into A549 cells [104].
Formulation and characterization of gelatin methacrylamide-hydroxypropyl methacrylate based bioink for bioprinting applications
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Nithusha Kallingal, Rashmi Ramakrishnan, Kalliyana Krishnan V
The traditional cross-linking methods such as UV induced cross-linking are reported to cause cell damage and significant degradation of biomaterials, while redox polymerization is considered a effective cross-linking method due to its less toxic nature. The common cross-linking methods include photopolymerization, thermal application, UV rays, gamma (γ)-irradiation, ionic bonding, hydrophobic interactions, hydrogen bonding, self cross-linking, etc. Polymerization of acrylamide, acrylonitrile, methacrylamide and methyl methacrylate can be done using persulfates with different reducing agents. Persulfate redox polymerization systems are one of the most frequently employed initiators in aqueous (emulsion) polymerization of water-soluble monomers. The main advantages of using redox initiators are their lower activation energy of the reaction, which result in free-radical formation at a wide range of temperatures, i.e. the initiation reaction occurs relatively at lower temperatures (0–50 °C) and even lower. Redox polymerization allows hydrogels to get faster gelation time at a very low temperature, which help the gels to retain their shape without swelling or deswelling in water. Redox polymerization has wide industrial importance and possess excellent stability, low toxicity, and tunable gelation time [21,22].
Recent advance in functionalized mesoporous silica nanoparticles with stimuli-responsive polymer brush for controlled drug delivery
Published in Soft Materials, 2022
A similar concept was also applied to the development and use of hollow mesoporous silica (HmSiO2) particle-based multifunctional superparamagnetic nanocarriers for delivery of DOX for cancer treatment. The HmSiO2 was modified with a thermo-responsive polymer of poly(N-isopropylacrylamide) (PNIPAM) and methacrylamide (MAm) and after that embedded with iron oxide Fe3O4. This HmSiO2-F-P(NIPAM-MAm)-DOX system showed a pH and temperature-dependent response for DOX release. The encapsulation efficiency of HmSiO2-F-P(NIPAM-MAm) nanocarriers was found to be ~95%, and their encapsulation capacity was found to be ~6.8%. The DOX release profile from the nanocarrier was observed at temperature 37°C and 40°C in buffer of pH 7.4 (to mimic blood plasma pH), respectively. It was found that ~18% of the loaded DOX was released at temperature below LCST (37°C) after 1 h, while ~40% of the drug was released at temperature above LCST (40°C). The results also indicated that DOX release was faster at temperatures above the LCST (40°C) than at temperatures below the LCST. This was due to the fact that P(NIPAM-MAm) brush became hydrophobic and thus shrinks at temperatures below LCST, which leads to the closing of pores on HmSiO2 nanoparticles. In contrast, the thermoresponsive P(NIPAM-MAm) extended and became swollen at temperature above LCST, allowing the MSNs’ pores to open. Cytotoxicity studies of showed that HmSiO2-F-P(NIPAM-MAm)-DOX had a good anticancer activity against Hela cells.[39]
Boron-incorporating hemagglutinating virus of Japan envelope (HVJ-E) nanomaterial in boron neutron capture therapy
Published in Science and Technology of Advanced Materials, 2019
Shuichiro Yoneoka, Yasuhiro Nakagawa, Koichiro Uto, Kazuma Sakura, Takehiko Tsukahara, Mitsuhiro Ebara
The boronated copolymer is composed of poly(2-methacryloyloxyethyl phosphorylcholine) (MPC) with methacrylamide benzoxaborole (MAAmBO), termed as poly[MPC-co-MAAmBO]. As shown in our conceptual illustration (Figure 1), since benzoxaborole (BO) is capable of binding to monosaccharides such as galactose in neutral buffer solution with pH above 7.6 because of the formation of ionized B(OH)2– groups of BO, the poly[MPC-co-MAAmBO] should be modified onto HVJ-E surfaces [37–42]. The synthesized poly[MPC-co-MAAmBO] was characterized by 1H and 11B nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), dynamic light scattering (DLS), and atomic force microscope (AFM) measurements.