| 1. |
- Barman, Jharna, et al.
(författare)
-
2 '-N-Guanidino, 4 '-C-ethylene bridged thymidine (GENA-T) modified oligonucleotide exhibits triplex formation with excellent enzymatic stability
- 2015
-
Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:16, s. 12257-12260
-
Tidskriftsartikel (refereegranskat)abstract
- Here we present the synthesis and characterization of a new 2'-N-Guanidino, 4'-C-ethylene bridged thymidine (GENA-T) modified oligonucleotide possessing North-locked sugar conformation. Incorporation of GENA-T nucleotide though did not change the thermal stability of the oligonucleotides toward the complementary RNA; it significantly increased the stability of the parallel triplex at pH 7. The melting temperature of the triplex was increased by +9.5 degrees C as compared to that of the isosequential unmodified sequence. Moreover this modification imparted exceptional nuclease stability to the oligonucleotides for over 33 h. This study clearly demonstrates that GENA-T modified oligonucleotides could improve triplex formation with phenomenal enzymatic stability and could be used for various biomedical applications.
|
|
| 2. |
|
|
| 3. |
- Oommen, Oommen Podiyan, et al.
(författare)
-
Multifunctional Hyaluronic Acid and Chondroitin Sulfate Nanoparticles : Impact of Glycosaminoglycan Presentation on Receptor Mediated Cellular Uptake and Immune Activation
- 2016
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:32, s. 20614-20624
-
Tidskriftsartikel (refereegranskat)abstract
- Hyaluronic acid (HA) and chondroitin sulfate (CS) polymers are extensively used for various biomedical applications, such as for tissue engineering, drug delivery, and gene delivery. Although both these biopolymers are known to target cell surface CD44 receptors, their relative cellular targeting properties and immune activation potential have never been evaluated. In this article, we present the synthesis and characterization of novel self assembled supramolecular HA and CS nanoparticles (NPs). These NPs were developed using fluorescein as a hydrophobic component that induced amphiphilicity in biopolymers and also efficiently stabilized anticancer drug doxorubicin (DOX) promoting a near zero-order drug release. The cellular uptake and cytotoxicity studies of these NPs in different human cancer lines, namely, human colorectal carcinoma cell line HCT116 and human breast cancer cell line MCF-7 demonstrated dose dependent cytotoxicity. Interestingly, both NPs showed CD44 dependent cellular uptake with the CS DOX NP displaying higher dose-dependent cytotoxicity than the HA DOX NP in different mammalian cells tested. Immunological evaluation of these nanocarriers in an ex vivo human whole blood model revealed that unlike unmodified polymers, the HA NP and CS NP surprisingly showed platelet aggregation and thrombin antithrombin complex formation at high concentrations (0.8 mg/mL). We also observed a clear difference in early- and late-stage complement activation (C3a and sC5b-9) with CS and CS NP triggering significant complement activation at high concentrations (0.08-0.8 mg/mL), unlike HA and HA NP. These results offer new insight into designing glycosaminoglycan-based NPs and understanding their hematological responses and targeting ability.
|
|
| 4. |
- Wang, Shujiang, et al.
(författare)
-
Insights into the Mechanism and Catalysis of Oxime Coupling Chemistry at Physiological pH
- 2015
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 21:15, s. 5980-5985
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamic covalent-coupling reaction involving alpha-effect nucleophiles has revolutionized bioconjugation approaches, due to its ease and high efficiency. Key to its success is the discovery of aniline as a nucleophilic catalyst, which made this reaction feasible under physiological conditions. Aniline however, is not so effective for keto substrates. Here, we investigate the mechanism of aniline activation in the oxime reaction with aldehyde and keto substrates. We also present carboxylates as activating agents that can promote the oxime reaction with both aldehyde and keto substrates at physiological pH. This rate enhancement circumvents the influence of alpha-effect by forming H-bonds with the rate-limiting intermediate, which drives the reaction to completion. The combination of aniline and carboxylates had a synergistic effect, resulting in a similar to 14-31-fold increase in reaction rate at pD 7.4 with keto substrates. The biocompatibility and efficiency of carboxylate as an activating agent is demonstrated by performing cell-surface oxime labeling at physiological pH using acetate, which showed promising results that were comparable with aniline.
|
|
| 5. |
- Bermejo, Daniel, 1985-, et al.
(författare)
-
First Aldol-Crosslinked Hyaluronic Acid Hydrogel: Fast and Hydrolytically Stable Gel with Tissue Adhesive Properties
-
Ingår i: Chemical Sciences Journal. - 2150-3494.
-
Tidskriftsartikel (refereegranskat)abstract
- Currently, there are limited approaches to tailor 3D scaffolds crosslinked with a stable covalent C-C bond that does not require any catalysts or initiators. We present here the first hydrogels employing aldol condensation chemistry that exhibit exceptional physicochemical properties. We investigated the aldol-crosslinking chemistry using two types of aldehyde-modified hyaluronic acid (HA) derivatives, namely; an enolizable HA-aldehyde (HA-Eal) and a non-enolizable HA-aldehyde (HA-Nal). Hydrogels formed using HA-Eal demonstrate inferior crosslinking efficiency (due to intramolecular loop formation), when compared with hydrogels formed by mixing HA-Eal and HA-NaI leading to a cross-aldol product. The change in mechanical properties as a result of crosslinking at different pH is determined using rheological measurements and is interpreted in terms of molecular weight between cross-links (Mc). The novel HA cross-aldol hydrogels demonstrate excellent hydrolytic stability and favorable mechanical properties but allow hyaluronidase mediated enzymatic degradation. Interestingly, residual aldehyde functionality within the aldol product leads to adhesion to tissue as demonstrated by bonding two bone tissues. The aldehyde functionality also permits facile post-synthetic modifications with nucleophilic reagents such as Alexa FluorTM 488. Finally, we demonstrate that the novel hydrogel is biocompatible with encapsulated stem cells that show a linear rate of expansion in our 3–6 days of study.
|
|
| 6. |
- Kadekar, Sandeep, et al.
(författare)
-
Synthetic design of asymmetric miRNA with engineered 3′-overhang to improve strand selection
- 2019
-
Ingår i: Molecular Therapy Nucleic Acids. - : Elsevier. - 2162-2531. ; 16, s. 597-604
-
Tidskriftsartikel (refereegranskat)abstract
- We have developed a novel miRNA design that significantly improves strand selection within the RISC complex by engineering the 3′-end by adding extra nucleotides. Addition of seven nucleotides at the 3′-ends of the miR or miR* strand resulted in a thermodynamic asymmetry at either of the two-ends, which resulted in selective RISC recruitment as demonstrated by the stem-loop quantitative PCR experiment. Such selective recruitment was also corroborated at the protein level by Western blot analysis. In order to investigate the functional effect due to selective recruitment, we performed apoptosis and metastasis studies using human colon carcinoma cells (HCT116) and human osteosarcoma cells (MG63). These experiments indicated that the recruitment of miR strand is responsible for inducing apoptosis as well as to inhibit invasiveness of cancer cells. Recruitment of miR* strand, on the other hand, showed opposite effect. To the best of our knowledge, our strand engineering strategy is the first report of improved strand selection of desired miRNA strand by RISC without using any chemical modifications or mismatches. We believe such structural modifications of miR34a could mitigate some of the off-target effects of miRNA therapy and would also allow a better understanding of sequence-specific gene regulation. Such a design could also be adapted to other miRNA to enhance their therapeutic potential.
|
|
| 7. |
- Kisiel, Marta, et al.
(författare)
-
Critical assessment of rhBMP-2 mediated bone induction : An in vitro and in vivo evaluation.
- 2012
-
Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 162:3, s. 646-653
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the influence of formulation and storage conditions on rhBMP-2 bioactivity is extremely important for its clinical application. Reports in the literature show that different research groups employ different parameters such as formulation conditions, storage, doses for in vivo applications etc. that makes it difficult to correlate results from different experiments. We therefore decided to rationalize these anomalies by performing a basic study on such parameters using two commercially available BMPs. Our in vitro experiments suggest that BMPs from different sources have significant differences in their bioactivity. The clinically approved rhBMP-2 (InductOs®; BMP-P) showed superior stability, compared to rhBMP-2 from R&D Systems (BMP-R) at physiological pH (determined by ALP assay). This BMP-P also showed lower binding to polypropylene Eppendorf tube. The BMP-R almost lost its bioactivity within 30min at physiological pH and also shows more adhesion to plastic surfaces. This aggregation behavior was unequivocally ascertained by performing light scattering studies of the two BMPs, which revealed linear aggregation with time for BMP-R unlike BMP-P. The in vitro results were also reflected in the in vivo experiments, in a rat ectopic model with injectable hyaluronic acid (HA) hydrogel as BMP carrier. After 7weeks post-implantation we observed larger bone volume with oriented collagen in the BMP-P group but a smaller bone with disoriented collagen in the BMP-R case. Our results highlight the large difference in activity between seemingly identical substances and also the importance of proper handling of such sensitive proteins.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Podiyan, Oommen, 1977-, et al.
(författare)
-
Smart design of stable hydrazone crosslinked extracellular matrix mimetic hydrogel for tissue engineering application
- 2012
-
Ingår i: Journal of Tissue Engineering and Regenerative Medicine. - : Hindawi Limited. - 1932-6254. ; 6:suppl 1, s. 192-192
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Injectable hydrogels are important biomaterials with enormous applications. They are used for various biomedical applications such as diagnostics, 3D cell culture matrix, drug reservoir, encapsulation of bioactive compounds and growth factors, scaffold for tissue engineering etc. We here present our recent development in our efforts to develop hydrogel scaffolds with enhanced rigidity, stability, swelling characteristics. Hydrazone crosslinked gels are attractive due to its simplicity and versatility which could be formed by mixing appropriate aldehyde and hydrazide functionalized hyaluronan. By fine-tuning the electronic character around the hydrazone linkage, we succeeded in developing extremely stable hydrazone bond and utilized it for developing hyaluronan (HA) based synthetic extracellular matrix (ECM) hydrogel. Among the different hydrazides tested, we identified carbonyldihydrazide (CDH) as the best candidate to deliver stable hydrazone linkage. This stability is presumably due to extensive delocalization of the positive charge across neighboring amino groups of CDH. The hydrolytic stability imparted by this group was found to be several folds under acidic, basic and physiological pH when compared to other hydrazones. This tailored hydrogel with CDH also exhibited superior swelling and mechanical properties and enzymatic stability which makes it ideal for tissue engineering application.
|
|
