Immobilization of Chitosan on the Plasma-Activated Poly-L-Lactic Acid Film Surface Using Evaporated Acrylic Acid as the Intermediate

2006 ◽  
Vol 49 ◽  
pp. 197-202
Author(s):  
Chih Ling Huang ◽  
Ying Yi Lin ◽  
Jiunn Der Liao
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Acrylic Acid ◽  
Film Surface ◽  
Thermal Cracking ◽  
Fibroblastic Cell ◽  
Chemical Structures ◽  
Plla Film ◽  
Growth Assay

Nerve bridging is to suture a biomaterial-made conduit and to overpass the damaged nerve end to end with microsurgery. Poly L-lactide (PLLA) is an excellent biomaterial that has biocompatible, biodegradable and good mechanical properties; it is thus potential to be engineered as nerve conduits and manufactured as scaffolds for nerve tissue replacement. On the other hand, chitosan provides cell affinity and considerably promotes nerves regeneration. This study is to apply plasma processing for PLLA film modification, graft the plasma-modified film with vaporized acrylic acid (AAc) monomers and then immobilize chitosan by amide bonding on the pAAc-grafted surface. This work using plasma-activation and subsequent evaporation of AAc greatly avoids PLLA thermal cracking and remaining the PLLA film in good mechanical properties. Surface morphologies are evaluated by Nano Focus. Electron Spectroscopy for Chemical Analysis (ESCA) and Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR) are respectively employed for determining elements’ functionalities and chemical structures. Moreover, biological functionalities of the chitosan-immobilized PLLA films are thereafter assessed by antibacterial test and in vitro fibroblastic cell growth assay. The result exhibits that chitosan is immobilized on the modified PLLA films, which is plasma-activated subsequent to the evaporation of AAc. The process does not induce thermal cracking. In vitro fibroblastic cell growth assay on the chitosan-immobilized PLLA films has demonstrated that fibroblast cells on the surface become circular in shape. It decreases cell growth rate and the development of scar tissues, which may thereafter promote the effect of nerve repairing.

scholarly journals Preparation and characterization of electrospun graphene/silk fibroin conductive fibrous scaffolds

RSC Advances ◽  
2017 ◽  
Vol 7 (13) ◽  
pp. 7954-7963 ◽  
Author(s):  
Yi Yang ◽  
Xili Ding ◽  
Tongqiang Zou ◽  
Ge Peng ◽  
Haifeng Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Silk Fibroin ◽  
Electrospinning Technique ◽  
Fibrous Scaffold ◽  
Fibrous Scaffolds

A conductive fibrous scaffold made of silk fibroin and graphene was developed using electrospinning technique. The 3% G/SF scaffolds showed improved electroactivity and mechanical properties. Moreover, they could support the cell growth in vitro.

The Effect of Cellulose Nanofibres on Mechanical Properties and Bioactivity of Natural Polymers

2013 ◽  
Vol 1498 ◽  
pp. 85-89
Author(s):  
Ali Negahi Shirazi ◽  
Ali Fathi ◽  
Fariba Dehghani
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Mechanical Strength ◽  
Polymer Network ◽  
Interpenetrating Polymer Network ◽  
Nano Particles ◽  
Osteosarcoma Cell ◽  
Natural Polymers ◽  
Cellulose Nanofibres

ABSTRACTNatural polymers, used for hydrogel fabrication, are generally bioactive and provide good environment for cell growth and proliferation. However, these polymers have low mechanical strength. Several approaches have been attempted to improve their mechanical properties such as fabrication of interpenetrating polymer network (IPN) and semi-IPN hydrogels, and also addition of a nano sized fibers or nano-particles. The aim of this study was to investigate the feasibility of using naturally derived nano-fillers such as cellulose nanocrystallines to enhance the mechanical properties of hydrogels. Gelatin methacrylate (GelMA) was used as a protein model for preparation of photo-crosslinked hydrogel. The effects of concentrations of photo initiator and cellulose nanocrystallines (CNC) on the characteristics of hydrogels were examined. In vitro studies showed negligible cytotoxic effect of CNC on human osteosarcoma cell growth when using less than 20 mg/ml CNC. Therefore, it is viable to use this nano-filler for biomedical applications. It was found that the compression modulus of gelatin hydrogel was increased 1.5 fold by addition of 10 mg/ml of CNC. These results demonstrate the high potential of using CNC for tissue engineering applications to enhance the mechanical strength of hydrogels.

The Biocompatibility of Silk Scaffold for Tissue Engineered Ligaments

2007 ◽  
Vol 342-343 ◽  
pp. 73-76 ◽  
Author(s):  
Young Kwon Seo ◽  
Gung Min Choi ◽  
Soon Yong Kwon ◽  
Hwa Sung Lee ◽  
Yong Soon Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cell Growth ◽  
Mononuclear Cells ◽  
Inflammatory Responses ◽  
Histological Evaluation ◽  
Artificial Ligament ◽  
Silk Scaffold ◽  
Tissue Reactions

The aim of this study was to estimate the mechanical properties and evaluate the biocompatibility of silk and PGA scaffolds as an artificial ligament to an ACL reconstruction. The scaffold for the artificial ligament was braided / knitted silk or PGA thread. The mechanical properties, cell growth, and subcutaneous tissue reactions were determined for both types of scaffolds. The breaking load of the PGA scaffold was double that of the sericin removed silk scaffold (SRSS). However, the initial attachment and growth of human ACL cells on the SRSS was superior to the PGA scaffold. In addition, the immune response was significantly higher on the PGA scaffold after 72 h (p<0.05) compared with the sericin removed silk scaffold by T lymphocyte and mononuclear cells (MNCs) in vitro cultures. In vivo, the ACL scaffold made from silk or PGA were implanted in the subcutaneous layer in rats and harvested 1 week later. A histological evaluation of the scaffolds explants revealed the presence of monocytes in the SRSS, and an absence of giant cells in all cases. An inflammatory tissue reaction was more conspicuous around the silk scaffold containing sericin and even more around the PGA scaffold compared with SRSS. These results support the conclusion that a properly prepared SRSS, aside from providing benefits in terms of biocompatibility both in vitro and in vivo, can provide suitable scaffolds for the support of ACL cell growth. These results suggest that a SRSS for ACL repair can overcome the current limitations with the PGA scaffold. And SRSS is biocompatible, and the in vitro T cell and MNCs culture model showed inflammatory responses that were comparable to those observed in vivo.

794: Valproic Acid Inhibits Prostate Cancer Cell Growth in Vitro and in Vivo

2006 ◽  
Vol 175 (4S) ◽  
pp. 257-257
Author(s):  
Jennifer Sung ◽  
Qinghua Xia ◽  
Wasim Chowdhury ◽  
Shabana Shabbeer ◽  
Michael Carducci ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Valproic Acid ◽  
Cell Growth ◽  
Cancer Cell ◽  
Prostate Cancer Cell ◽  
Cancer Cell Growth

Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications

2003 ◽  
Vol 774 ◽  
Author(s):  
Janice L. McKenzie ◽  
Michael C. Waid ◽  
Riyi Shi ◽  
Thomas J. Webster
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanofibers ◽  
Material Properties ◽  
Carbon Nanofiber ◽  
Scar Tissue ◽  
Tissue Response ◽  
Positive Interactions ◽  
Weight Percentage ◽  
Poly Carbonate

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.

Flavonoids as P-gp Inhibitors: A Systematic Review of SARs

2019 ◽  
Vol 26 (25) ◽  
pp. 4799-4831 ◽  
Author(s):  
Jiahua Cui ◽  
Xiaoyang Liu ◽  
Larry M.C. Chow
Keyword(s):  
Molecular Mechanisms ◽  
Metastatic Cancer ◽  
Drug Candidates ◽  
Chemical Structures ◽  
Transporter Family ◽  
Promising Area ◽  
New Generation ◽  
Nontoxic Inhibitors

P-glycoprotein, also known as ABCB1 in the ABC transporter family, confers the simultaneous resistance of metastatic cancer cells towards various anticancer drugs with different targets and diverse chemical structures. The exploration of safe and specific inhibitors of this pump has always been the pursuit of scientists for the past four decades. Naturally occurring flavonoids as benzopyrone derivatives were recognized as a class of nontoxic inhibitors of P-gp. The recent advent of synthetic flavonoid dimer FD18, as a potent P-gp modulator in reversing multidrug resistance both in vitro and in vivo, specifically targeted the pseudodimeric structure of the drug transporter and represented a new generation of inhibitors with high transporter binding affinity and low toxicity. This review concerned the recent updates on the structure-activity relationships of flavonoids as P-gp inhibitors, the molecular mechanisms of their action and their ability to overcome P-gp-mediated MDR in preclinical studies. It had crucial implications on the discovery of new drug candidates that modulated the efflux of ABC transporters and also provided some clues for the future development in this promising area.

Novel Phytochemical Constituents and their Potential to Manage Diabetes

2020 ◽  
Vol 26 ◽  
Author(s):  
Shaik Ibrahim Khalivulla ◽  
Arifullah Mohammed ◽  
Kokkanti Mallikarjuna
Keyword(s):  
Natural Products ◽  
Large Population ◽  
World Health ◽  
In Vivo Studies ◽  
Antidiabetic Activity ◽  
Therapeutic Drug ◽  
Pharmacological Activities ◽  
Chemical Structures

Background: Diabetes is a chronic disease affecting a large population worldwide and stands as one of the major global health challenges to be tackled. According to World Health Organization, about 400 million are having diabetes worldwide and it is the seventh leading cause of deaths in 2016. Plant based natural products had been in use from ancient time as ethnomedicine for the treatment of several diseases including diabetes. As a result of that, there are several reports on plant based natural products displaying antidiabetic activity. In the current review, such antidiabetic potential compounds reported from all plant sources along with their chemical structures are collected, presented and discussed. This kind of reports are essential to pool the available information to one source followed by statistical analysis and screening to check the efficacy of all known compounds in a comparative sense. This kind of analysis can give rise to few numbers of potential compounds from hundreds, whom can further be screened through in vitro and in vivo studies, and human trails leading to the drug development. Methods: Phytochemicals along with their potential antidiabetic property were classified according to their basic chemical skeleton. The chemical structures of all the compounds with antidiabetic activities were elucidated in the present review. In addition to this, the distribution and their other remarkable pharmacological activities of each species is also included. Results: The scrutiny of literature led to identification of 44 plants with antidiabetic compounds (70) and other pharmacological activities. For the sake of information, the distribution of each species in the world is given. Many plant derivatives may exert antidiabetic properties by improving or mimicking the insulin production or action. Different classes of compounds including sulfur compounds (1-4), alkaloids (5-11), phenolic compounds (12-17), tannins (18-23), phenylpropanoids (24-27), xanthanoids (28-31), amino acid (32), stilbenoid (33), benzofuran (34), coumarin (35), flavonoids (36-49) and terpenoids (50-70) were found to be active potential compounds for antidiabetic activity. Of the 70 listed compounds, majorly 17 compounds are from triterpenoids, 13 flavonoids and 7 are from alkaloids. Among all the 44 plant species, maximum number (7) of compounds are reported from Lagerstroemia speciosa followed by Momordica charantia (6) and S. oblonga with 5 compounds. Conclusion: This is the first paper to summarize the established chemical structures of phytochemicals that have been successfully screened for antidiabetic potential and their mechanisms of inhibition. The reported compounds could be considered as potential lead molecules for the treatment of type-2 diabetes. Further, molecular and clinical trials are required to select and establish the therapeutic drug candidates.

Polyamines and Related Nitrogen Compounds in the Chemotherapy of Neglected Diseases Caused by Kinetoplastids

2018 ◽  
Vol 18 (5) ◽  
pp. 321-368 ◽  
Author(s):  
Juan A. Bisceglia ◽  
Maria C. Mollo ◽  
Nadia Gruber ◽  
Liliana R. Orelli
Keyword(s):  
Drug Targets ◽  
Redox Homeostasis ◽  
Cost Effective ◽  
Structural Features ◽  
Mammalian Host ◽  
Neglected Diseases ◽  
Nitrogen Compounds ◽  
Chemical Structures

Neglected diseases due to the parasitic protozoa Leishmania and Trypanosoma (kinetoplastids) affect millions of people worldwide, and the lack of suitable treatments has promoted an ongoing drug discovery effort to identify novel nontoxic and cost-effective chemotherapies. Polyamines are ubiquitous small organic molecules that play key roles in kinetoplastid parasites metabolism, redox homeostasis and in the normal progression of cell cycles, which differ from those found in the mammalian host. These features make polyamines attractive in terms of antiparasitic drug development. The present work provides a comprehensive insight on the use of polyamine derivatives and related nitrogen compounds in the chemotherapy of kinetoplastid diseases. The amount of literature on this subject is considerable, and a classification considering drug targets and chemical structures were made. Polyamines, aminoalcohols and basic heterocycles designed to target the relevant parasitic enzyme trypanothione reductase are discussed in the first section, followed by compounds directed to less common targets, like parasite SOD and the aminopurine P2 transporter. Finally, the third section comprises nitrogen compounds structurally derived from antimalaric agents. References on the chemical synthesis of the selected compounds are reported together with their in vivo and/or in vitro IC50 values, and structureactivity relationships within each group are analyzed. Some favourable structural features were identified from the SAR analyses comprising protonable sites, hydrophobic groups and optimum distances between them. The importance of certain pharmacophoric groups or amino acid residues in the bioactivity of polyamine derived compounds is also discussed.

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