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1.
Biomacromolecules ; 25(7): 4139-4155, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38924768

RESUMO

Extracellular vesicles (EVs) derived from bone progenitor cells are advantageous as cell-free and non-immunogenic cargo delivery vehicles. In this study, EVs are isolated from MC3T3-E1 cells before (GM-EVs) and after mineralization for 7 and 14 days (DM-EVs). It was observed that DM-EVs accelerate the process of differentiation in recipient cells more prominently. The small RNA sequencing of EVs revealed that miR-204-5p, miR-221-3p, and miR-148a-3p are among the highly upregulated miRNAs that have an inhibitory effect on the function of mRNAs, Sox11, Timp3, and Ccna2 in host cells, which is probably responsible for enhancing the activity of osteoblastic genes. To enhance the bioavailability of EVs, they are encapsulated in a chitosan-collagen composite hydrogel that serves as a bioresorbable extracellular matrix (ECM). The EVs-integrated scaffold (DM-EVs + Scaffold) enhances bone regeneration in critical-sized calvarial bone defects in rats within 8 weeks of implantation by providing the ECM cues. The shelf life of DM-EVs + Scaffold indicates that the bioactivity of EVs and their cargo in the polymer matrix remains intact for up to 30 days. Integrating mineralized cell-derived EVs into an ECM represents a bioresorbable matrix with a cell-free method for promoting new bone formation through the miRNA-mRNA regulatory axis.


Assuntos
Regeneração Óssea , Matriz Extracelular , Vesículas Extracelulares , MicroRNAs , Osteoblastos , RNA Mensageiro , Regeneração Óssea/efeitos dos fármacos , Animais , MicroRNAs/genética , Osteoblastos/metabolismo , Vesículas Extracelulares/química , Vesículas Extracelulares/metabolismo , Ratos , Camundongos , Matriz Extracelular/metabolismo , RNA Mensageiro/genética , Diferenciação Celular , Alicerces Teciduais/química , Osteogênese/efeitos dos fármacos , Polissacarídeos/química , Ratos Sprague-Dawley , Masculino
2.
ACS Omega ; 9(16): 17891-17902, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38680357

RESUMO

Matrix elasticity helps to direct bone cell differentiation, impact healing processes, and modify extracellular matrix deposition, all of which are required for tissue growth and maintenance. In this work, we evaluated the role of inorganic nanocrystals or mineral inducers such as nanohydroxyapatite, alkaline phosphatase, and nanoclay also known as montmorillonite deposited on vinyl-based hydrogels in generating matrices with different stiffness and their role in cell differentiation. Poly-2-(dimethylamino)ethyl methacrylate (PD) and poly-2-hydroxypropylmethacrylamide (PH) are the two types of vinyl polymers chosen for preparing hydrogels via thermal cross-linking. The hydrogels exhibited porosity, which decreased with an increase in stiffness. Each of the compositions is non-cytotoxic and maintains the viability of pre-osteoblasts (MC3T3-E1) and human bone marrow mesenchymal stem cells (hBMSCs). The PD hydrogels in the presence of ALP showed the highest mineralization ability confirmed through the alizarin assay and a better structural environment for their use as scaffolds for tissue engineering. The study reveals that understanding such interactions can generate hydrogels that can serve as efficient 3D models to study biomineralization.

3.
ACS Biomater Sci Eng ; 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39150495

RESUMO

Osteosarcoma (OS) is a rare malignant tumor that affects soft tissue and has high rates of lung metastasis and mortality. The primary treatments for OS include preoperative chemotherapy, surgical resection of the lesion, and postoperative chemotherapy. However, OS chemotherapy presents critical challenges related to treatment toxicity and multiple drug resistance. To address these challenges, nanotechnology has developed nanosystems that release drugs directly to OS cells, reducing the drug's toxicity. Extracellular vesicles (EVs) are nanosized lipid-bilayer bound vesicles that act as cell-derived vehicles and drug delivery systems for several cancers. This study aims to utilize EVs for OS management by co-delivering Hdac1 siRNA and zoledronic acid (zol). The EVs' surface is modified with folic acid (FA) and their targeting ability is compared to that of native EVs. The results showed that the EVs' targeting ability depends on the parent cell source, and FA conjugation further enhanced it. Furthermore, EVs were used as the carrier for co-loading drug (zol) and small RNA (Hdac-1). This approach of using surface engineered EVs as carriers for cargo loading and delivery can be a promising strategy for osteosarcoma management.

4.
Chem Soc Rev ; 41(21): 7147-94, 2012 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-22885409

RESUMO

The last decade has witnessed enormous research focused on cationic polymers. Cationic polymers are the subject of intense research as non-viral gene delivery systems, due to their flexible properties, facile synthesis, robustness and proven gene delivery efficiency. Here, we review the most recent scientific advances in cationic polymers and their derivatives not only for gene delivery purposes but also for various alternative therapeutic applications. An overview of the synthesis and preparation of cationic polymers is provided along with their inherent bioactive and intrinsic therapeutic potential. In addition, cationic polymer based biomedical materials are covered. Major progress in the fields of drug and gene delivery as well as tissue engineering applications is summarized in the present review.


Assuntos
Materiais Biocompatíveis/química , Portadores de Fármacos/química , Polímeros/química , Animais , Materiais Biocompatíveis/farmacologia , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Portadores de Fármacos/farmacologia , Técnicas de Transferência de Genes , Humanos , Polímeros/farmacologia , Engenharia Tecidual
5.
Macromol Biosci ; 23(11): e2300211, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37384621

RESUMO

Osteosarcoma (OS) is a malignant tumor, fatal for pediatric patients who do not respond to chemotherapy, alternative therapies and drugs can provide better outcomes. Zoledronic acid (Zol) belonging to the class of bisphosphonates (BPs) has a direct antitumor ability to prevent Ras GTPases modification and stimulate apoptosis. Despite advances in maintaining balance in skeletal events and direct anticancer properties, Zol causes cytotoxicity to normal healthy pre-osteoblast cells, hampering mineralization and differentiation. The study reports the preparation and evaluation of a nanoformulation that can diminish the existing drawbacks of native Zol. The cytotoxic effect is evaluated on bone cancer cells and healthy bone cells with three different cell lines namely, K7M2 (mouse OS cell line), SaOS2 (human OS cell line), and MC3T3E1 (healthy cell counterpart). It is observed that Zol nanoformulation is uptaken more (95%) in K7M2 whereas in MC3T3E1, the percent population internalizing nanoparticles (NPs) is 45%. Zol has a sustained release of 15% after 96 h from the NP which leads to a rescuing effect on the normal pre-osteoblast cells. In conclusion, it can be stated that Zol nanoformulation can be used as a good platform for a sustained release system with minimum side effects to normal bone cells.


Assuntos
Antineoplásicos , Neoplasias Ósseas , Osteossarcoma , Camundongos , Animais , Humanos , Criança , Ácido Zoledrônico/farmacologia , Ácido Zoledrônico/uso terapêutico , Preparações de Ação Retardada/farmacologia , Imidazóis/farmacologia , Proliferação de Células , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Difosfonatos/farmacologia , Difosfonatos/uso terapêutico , Osteossarcoma/metabolismo , Osteoblastos , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral
6.
Adv Healthc Mater ; 12(32): e2301959, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37712303

RESUMO

Glycoproteins are gaining prominence as multifunctional biomaterials. The study reports development of glycoprotein mucin as biomaterial promoting bone regeneration. Mucin 1 deletion has resulted in stiffer femoral bones with scarce presence of osteoblasts in trabecular linings and its role has been established in determining bone mass and mineralization. Limited information about its structure limits its processability, exploration as biomaterial, which is discussed in this study. The role of mucin in ECM (extracellular cellular matrix) formation validated by RNA sequencing analysis of human bone marrow derived mesenchymal stem cells is reported. The structure and stability of mucins is dependent on the presence of glycans in its structure. A thermosensitive hydrogel acquired from thermosensitive Poly (N-isopropyl acrylamide)-(PNIPAM) modified mucin and collagen is developed. The hydrogel demonstrates porous structure and mechanical strength. Newly formed bone tissue is observed at 8 weeks post-implantation in the hydrogel treated groups. The formation of blood vessels, nerves, and bone is observed with upregulation of angiopoietin (ANG), neurofilament heavy chain (NF-H), and osteoadherin (OSAD) or osteocalcin (OCN) respectively in rat calvarial defects. The outcome demonstrates that the thermosensitive injectable hydrogel accelerates repair and healing in calvarial bone defects making it a promising biodegradable biomaterial capable of regenerating bone by promoting angiogenesis and innervation.


Assuntos
Angiogênese , Hidrogéis , Ratos , Humanos , Animais , Hidrogéis/farmacologia , Hidrogéis/química , Regeneração Óssea , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/química , Glicoproteínas/farmacologia , Mucinas
7.
RSC Adv ; 12(53): 34463-34481, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36545618

RESUMO

Rise in global population has increased the food demands and thus the competition among farmers to produce more and more. In the race to obtain higher productivity, farmers have resorted to injudicious farming practices that include the reckless use of nitrogenous fertilizers and intensive cropping on farmlands. Such practices have paved the path for large scale infestations of crops and plants by pests thus affecting the plant productivity and crop vigour. There are several traditional techniques to control pest infestations in plants such as the use of chemical or bio-pesticides, and integrated pest management practices which face several drawbacks. Delivery of gene/nucleic acid in plants through genetic engineering approaches is a more sustainable and effective method of protection against pests. The technology of RNA interference (RNAi) provides a sustainable solution to counter pest control problems faced by other traditional techniques. The RNAi technique involves delivery of dsDNA/dsRNA or other forms of nucleic acids into target organisms thereby bringing about gene silencing. However, RNAi is also limited to its use because of their susceptibility to degradation wherein the use of cationic polymers can provide a tangible solution. Cationic polymers form stable complexes with the nucleic acids known as "polyplexes", which may be attributed to their high positive charge densities thus protecting the exogenous nucleic acids from extracellular degradation. The current paper focuses on the utility of nucleic acids as a sustainable tool for pest control in crops and the use of cationic polymers for the efficient delivery of nucleic acids in pests thus protecting the plant from infestations.

8.
Int J Nanomedicine ; 16: 3509-3540, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34045855

RESUMO

The increasing incidence of bone-related disorders is causing a burden on the clinical scenario. Even though bone is one of the tissues that possess tremendous regenerative potential, certain bone anomalies need therapeutic intervention through appropriate delivery of a drug. Among several nanosystems and biologics that offer the potential to contribute towards bone healing, the exosomes from the class of extracellular vesicles are outstanding. Exosomes are extracellular nanovesicles that, apart from the various advantages, are standing out of the crowd for their ability to conduct cellular communication. The internal cargo of the exosomes is leading to its potential use in therapeutics. Exosomes are being unraveled in terms of the mechanism as well as application in targeting various diseases and tissues. Through this review, we have tried to understand and review all that is already established and the gap areas that still exist in utilizing them as drug delivery vehicles targeting the bone. The review highlights the potential of the exosomes towards their contribution to the drug delivery scenario in the bone microenvironment. A comparison of the pros and cons of exosomes with other prevalent drug delivery systems is also done. A section on the patents that have been generated so far from this field is included.


Assuntos
Osso e Ossos/citologia , Microambiente Celular/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Exossomos/metabolismo , Animais , Exossomos/efeitos dos fármacos , Humanos
9.
RSC Adv ; 11(48): 30329-30342, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35480259

RESUMO

The role of polymers has played a crucial role in developing templates that can promote regeneration as tissue-engineered matrices. The present study aims to develop functional matrices involving the protein mucin. The mucin used in this study is characterised using MALDI-TOF TOF and CD spectroscopy prior to conjugation. Thereupon, a hybrid scaffold comprising of a polysaccharide, chitosan, chemically conjugated to a protein, mucin, and encapsulated with montmorillonite is developed. Grafting of hydroxyethyl methacrylate (HEMA) is done to overcome the issue of mechanical weakness that mucin hydrogels usually undergo. It was observed that the presence of montmorillonite led to the stability of the hydrogels. The conjugations with varied ratios of the polysaccharide and protein were characterized using spectroscopic techniques. The prepared gels showed appreciable material properties in terms of water uptake and porosity. Hydrogels with different ratios of the polysaccharide and protein were evaluated for their biocompatibility. The biological evaluation of the hydrogels was performed with MC3T3E1 and C2C12 cell lines indicating their potential for wider tissue engineering applications.

10.
J Pharm Sci ; 110(12): 3757-3772, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34474062

RESUMO

The need for bone repair and insight into new regeneration therapies as well as improvement of existing regeneration routes is constantly increasing as a direct consequence of the rise in the number of trauma victims, musculoskeletal disorders, and increased life expectancy. Bisphosphonates (BPs) have emerged as a class of drugs with proven efficacy against many bone disorders. The most recent ability of this class of drugs is being explored in its anti-cancer ability. However, despite the pharmacological success, there are certain shortcomings that have circumvented this class of the drug. The mediation of biomaterials in delivering bisphosphonates has greatly helped in overcoming some of these shortcomings. This article is focused on reviewing the benefits the bisphosphonates have provided upon getting delivered via the use of biomaterials. Furthermore, the role of bisphosphonates as a potent anticancer agent is also accounted. It is witnessed that employing engineering tools in combination with therapeutics has the potential to provide solutions to bone loss from degenerative, surgical, or traumatic processes, and also aid in accelerating the healing of large bone fractures and problematic non-union fractures. The role of nanotechnology in enhancing the efficacy of the bisphosphonates is also reviewed and innovative approaches are identified.


Assuntos
Materiais Biocompatíveis , Difosfonatos , Cicatrização
11.
Macromol Biosci ; 21(6): e2000381, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33871165

RESUMO

Biomimetic matrices offer a great advantage to understand several biological processes including regeneration. The study involves the development of a hybrid biomimetic scaffold and the uniqueness lies in the use of mucin, as a constituent protein. Through this study, the role of the protein in bone regeneration is deciphered through its development as a 3D model. As a first step towards understanding the protein, the interactions of mucin and collagen are determined by in silico studies considering that collagen is the most abundant protein in the bone microenvironment. Both proteins are reported to be involved in bone biology though the exact role of mucin is a topic of investigation. The in silico studies of collagen-mucin suggest to have a proper affinity toward each other, forming a strong basis for 3D scaffold development. The developed 3D scaffold is a double network system comprising of mucin and collagen and vinyl end functionalized polyethylene glycol. In situ deposition of mineral crystals has been performed enzymatically. Biological evaluation of these mineral deposited scaffolds is done in terms of their bone regeneration potential and a comparison of the two systems with and without mineral deposition is presented.


Assuntos
Osso e Ossos/efeitos dos fármacos , Colágeno/química , Mucinas/química , Polímeros/química , Engenharia Tecidual/métodos , Alicerces Teciduais , Animais , Materiais Biomiméticos , Regeneração Óssea/efeitos dos fármacos , Regeneração Óssea/genética , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Bovinos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Colágeno/genética , Colágeno/metabolismo , Colágeno/farmacologia , Camundongos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Mucinas/genética , Mucinas/metabolismo , Mucinas/farmacologia , Células NIH 3T3 , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Polímeros/metabolismo , Polímeros/farmacologia , Ligação Proteica , Ratos
12.
J Control Release ; 327: 546-570, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-32911013

RESUMO

Targeted therapy approaches have become the core of modern translational science and as an intriguing field, it is the solution of the conventional drug delivery problems that were once unanswered. Traditional methods of delivering drugs and therapeutics faced issues of solubility, sustained release, not enough amount getting through the diseased site, for e.g a tumor. Various formulations of liposomes, polymers, dendrimers, etc have succeeded and made their way for clinical trials trying to enhance the pharmacokinetic and biodistribution of the drug. Many stealth coatings that include hydrophilic polymers (PEG, chitosan, polyacrylamides, etc) can act as a covering around the nanoparticle that can shield the surface from aggregation, opsonization and evade immune system, thus considered in Generally Recognized as Safe (GRAS) category. Several other polymers such as poly-2-oxazoline, polyethylene oxide, PEG-based surfactant (polysorbate-80), and zwitterionic phospholipids have also been tested for their antifouling properties. However, the polymer coating approach requires labor-intensive procedures and conjugation chemistries that often fail in mice model. Besides, due to immunogenicity and allergic reactions evoked by the PEG-coated nanoparticles, there was an urge to find biomimicking materials that can prove better as shielding agents which paved the way for cell membrane coated nanoparticles (CMCNPs) to come into the limelight. CMCNPs consist of a nanoparticle inner core covered by cell membrane that can be implicated in targeted drug delivery approaches, photothermal therapy, diagnosis or imaging making it a powerful theranostic tool. In this review, mode of preparation of CMCNPs, different sources of cell membranes (RBCs, WBCs, platelets, cancer cells, stem cells with some other unconventional sources) and nanoparticle cores that are employed have been thoroughly emphasized. In addition to this, advancements and limitations with respect to this newly emerging field have been focussed.


Assuntos
Biomimética , Nanopartículas , Animais , Membrana Celular , Sistemas de Liberação de Medicamentos , Camundongos , Polietilenoglicóis , Distribuição Tecidual
13.
Front Physiol ; 9: 316, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29670535

RESUMO

Lepidoptera comprise some of the most devastating herbivorous pest insects worldwide. One of the most promising novel pest control strategies is exploiting the RNA interference (RNAi) mechanism to target essential genes for knockdown and incite toxic effects in the target species without harming other organisms in the ecosystem. However, many insects are refractory to oral RNAi, often due to rapid degradation of ingested dsRNA in their digestive system. This is the case for many lepidopteran insects, including the beet armyworm Spodoptera exigua, which is characterized by a very alkaline gut environment (pH > 9.0) and a strong intestinal nucleolytic activity. In this research, guanidine-containing polymers were developed to protect dsRNA against nucleolytic degradation, specifically in high pH environments. First, their ability to protect dsRNA against nucleolytic degradation in gut juice of the beet armyworm S. exigua was investigated ex vivo. Polymers with high guanidine content provided a strong protection against nucleolytic degradation at pH 11, protecting the dsRNA for up to 30 h. Next, cellular uptake of the dsRNA and the polyplexes in lepidopteran CF203 midgut cells was investigated by confocal microscopy, showing that the polymer also enhanced cellular uptake of the dsRNA. Finally, in vivo feeding RNAi bioassays demonstrated that using these guanidine-containing polymer nanoparticles led to an increased RNAi efficiency in S. exigua. Targeting the essential gene chitin synthase B, we observed that the mortality increased to 53% in the polymer-protected dsRNA treatment compared to only 16% with the naked dsRNA and found that polymer-protected dsRNA completely halted the development of the caterpillars. These results show that using guanylated polymers as a formulation strategy can prevent degradation of dsRNA in the alkaline and strongly nucleolytic gut of lepidopteran insects. Furthermore, the polymer also enhances cellular uptake in lepidopteran midgut cells. This new delivery strategy could be of great use in further fundamental research in lepidopterans, using RNAi as a research tool, and could lead to future applications for RNAi-based pest control of lepidopteran insects.

14.
Carbohydr Polym ; 191: 127-135, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29661300

RESUMO

Tissue engineering (TE) approaches often employ polymer-based scaffolds to provide support with a view to the improved regeneration of damaged tissues. The aim of this research was to develop a surface modification method for introducing chitosan as an antibacterial agent in both electrospun membranes and 3D printed poly-ε-caprolactone (PCL) scaffolds. The scaffolds were functionalized by grafting methacrylic acid N-hydroxysuccinimide ester (NHSMA) onto the surface after Ar-plasma/air activation. Subsequently, the newly-introduced NHS groups were used to couple with chitosan of various molecular weights (Mw). High Mw chitosan exhibited a better coverage of the surface as indicated by the higher N% detected by X-ray photoelectron spectroscopy (XPS) and the observations with either scanning electron microscopy (SEM)(for fibers) or Coomassie blue staining (for 3D-printed scaffolds). A lactate dehydrogenase assay (LDH) using L929 fibroblasts demonstrated the cell-adhesion and cell-viability capacity of the modified samples. The antibacterial properties against S. aureus ATCC 6538 and S. epidermidis ET13 revealed a slower bacterial growth rate on the surface of the chitosan modified scaffolds, regardless the chitosan Mw.

15.
J Colloid Interface Sci ; 520: 64-69, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29529462

RESUMO

HYPOTHESIS: The complete removal of remaining polymer debris after stripping of optical fiber cables is essential for high precision connection between two fibers. It can be anticipated that electrospun porous membranes as cleaning wipes are able to trap and retain polymer debris within their pores. Impregnation of an oil-in-water emulsion as cleaning agent lowers the interfacial tension between debris and the optical fiber thereby enabling the straightforward removal of polymer debris from the optical fiber. EXPERIMENTS: Electrospun membranes of poly(ethylene terephthalate) (PET) and cellulose acetate (CA) were obtained with fiber diameters of 0.430 µm and 2 µm respectively. The oil-in-water emulsion was formulated with 10 wt% medium chain triglyceride (MCT) and 10 wt% Tween 80 surfactant in an aqueous phosphate buffer solution. FINDINGS: In a scoring range from 0 to 5 for which the score 0 indicated superior cleaning and the score 5 referred to the least efficient cleaning, the electrospun fiber mats (without emulsion) scored within the range of 2-4 while emulsion impregnated electrospun fiber mats revealed the best score of 0. A drastic improvement was thus clearly evident from the obtained results when the cleaning emulsion was applied. The materials developed herein thus represent a new class of soft cleaning agents for optical fibers.

16.
Carbohydr Polym ; 182: 254-264, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29279122

RESUMO

Polyelectrolyte complexes (PEC) of chitosan and ulvan were fabricated to study alkaline phosphatase (ALP) mediated formation of apatitic minerals. Scaffolds of the PEC were subjected to ALP and successful mineral formation was studied using SEM, Raman and XRD techniques. Investigation of the morphology via SEM shows globular structures of the deposited minerals, which promoted cell attachment, proliferation and extracellular matrix formation. The PEC and their successful calcium phosphate based mineralization offers a greener route of scaffold fabrication towards developing resorbable materials for tissue engineering.


Assuntos
Fosfatase Alcalina/metabolismo , Materiais Biocompatíveis/metabolismo , Quitosana/metabolismo , Polissacarídeos/metabolismo , Células 3T3 , Fosfatase Alcalina/química , Animais , Materiais Biocompatíveis/química , Configuração de Carboidratos , Adesão Celular , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Quitosana/química , Eletrólitos/química , Eletrólitos/metabolismo , Camundongos , Polissacarídeos/química
17.
J Tissue Eng Regen Med ; 11(5): 1500-1513, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-26076675

RESUMO

Porous biodegradable scaffolds represent promising candidates for tissue-engineering applications because of their capability to be preseeded with cells. We report an uncrosslinked chitosan scaffold designed with the aim of inducing and supporting enzyme-mediated formation of apatite minerals in the absence of osteogenic growth factors. To realize this, natural enzyme alkaline phosphatase (ALP) was incorporated into uncrosslinked chitosan scaffolds. The uncrosslinked chitosan makes available amine and alcohol functionalities to enhance the biomineralization process. The physicochemical findings revealed homogeneous mineralization, with the phase structure of the formed minerals resembling that of apatite at low mineral concentrations, and similar to dicalcium phosphate dihydrate (DCPD) with increasing ALP content. The MC3T3 cell activity clearly showed that the mineralization of the chitosan scaffolds was effective in improving cellular adhesion, proliferation and colonization. Copyright © 2015 John Wiley & Sons, Ltd.


Assuntos
Fosfatase Alcalina/metabolismo , Calcificação Fisiológica , Quitosana/química , Engenharia Tecidual , Alicerces Teciduais/química , Animais , Adesão Celular , Linhagem Celular , Proliferação de Células , Camundongos
18.
Carbohydr Polym ; 141: 28-40, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-26876993

RESUMO

Chitosan is a non-toxic, biocompatible, biodegradable natural cationic polymer known for its low imunogenicity, antimicrobial, antioxidant effects and wound-healing activity. To improve its therapeutic potential, new chitosan-sulfonamide derivatives have been designed to develop new wound dressing biomaterials. The structural, morphological and physico-chemical properties of synthesized chitosan derivatives were analyzed by FT-IR, (1)H NMR spectroscopy, scanning electron microscopy, swelling ability and porosity. Antimicrobial, in vivo testing and biodegradation behavior have been also performed. The chitosan derivative membranes showed improved swelling and biodegradation rate, which are important characteristics required for the wound healing process. The antimicrobial assay evidenced that chitosan-based sulfadiazine, sulfadimethoxine and sulfamethoxazole derivatives were the most active. The MTT assay showed that some of chitosan derivatives are nontoxic. Furthermore, the in vivo study on burn wound model induced in Wistar rats demonstrated an improved healing effect and enhanced epithelialization of chitosan-sulfonamide derivatives compared to neat chitosan. The obtained results strongly recommend the use of some of the newly developed chitosan derivatives as antimicrobial wound dressing biomaterials.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Bandagens , Quitosana/análogos & derivados , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/química , Antifúngicos/química , Porosidade , Ratos , Ratos Wistar , Molhabilidade
19.
J Tissue Eng Regen Med ; 10(11): 938-954, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-24616374

RESUMO

Mineralization of hydrogels, desirable for bone regeneration applications, may be achieved enzymatically by incorporation of alkaline phosphatase (ALP). ALP-loaded gellan gum (GG) hydrogels were mineralized by incubation in mineralization media containing calcium and/or magnesium glycerophosphate (CaGP, MgGP). Mineralization media with CaGP:MgGP concentrations 0.1:0, 0.075:0.025, 0.05:0.05, 0.025:0.075 and 0:0.1 (all values mol/dm3 , denoted A, B, C, D and E, respectively) were compared. Mineral formation was confirmed by IR and Raman, SEM, ICP-OES, XRD, TEM, SAED, TGA and increases in the the mass fraction of the hydrogel not consisting of water. Ca was incorporated into mineral to a greater extent than Mg in samples mineralized in media A-D. Mg content and amorphicity of mineral formed increased in the order A < B < C < D. Mineral formed in media A and B was calcium-deficient hydroxyapatite (CDHA). Mineral formed in medium C was a combination of CDHA and an amorphous phase. Mineral formed in medium D was an amorphous phase. Mineral formed in medium E was a combination of crystalline and amorphous MgP. Young's moduli and storage moduli decreased in dependence of mineralization medium in the order A > B > C > D, but were significantly higher for samples mineralized in medium E. The attachment and vitality of osteoblastic MC3T3-E1 cells were higher on samples mineralized in media B-E (containing Mg) than in those mineralized in medium A (not containing Mg). All samples underwent degradation and supported the adhesion of RAW 264.7 monocytic cells, and samples mineralized in media A and B supported osteoclast-like cell formation. Copyright © 2014 John Wiley & Sons, Ltd.


Assuntos
Calcificação Fisiológica , Fosfatos de Cálcio/química , Hidrogéis/química , Compostos de Magnésio/química , Osteoblastos/metabolismo , Fosfatos/química , Polissacarídeos Bacterianos/química , Engenharia Tecidual , Animais , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Masculino , Camundongos , Osteoblastos/citologia , Células RAW 264.7
20.
Eur J Pharm Sci ; 77: 122-34, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26079402

RESUMO

New xanthine derivatives as antidiabetic agents were synthesized and new chitosan formulations have been developed in order to improve their biological and pharmacokinetic profile. Their physicochemical properties in terms of particle size, morphology, swelling degree, crystalline state, the loading efficiency as well as in vitro release and biodegradation rate were evaluated. According to the results the optimized formulations have a high drug loading efficiency (more than 70%), small particle size, a good release profile in the simulated biological fluids (the percentage of cumulative release being more than 55%) and improved biodegradation rate in reference with chitosan microparticles. The presence of xanthine derivatives (6, 7) in chitosan microparticles was demonstrated by means of FTIR analysis. The X-ray diffraction (XRD) proved that xanthine derivatives present a crystalline state. The biological evaluation assays confirmed the antioxidant and antidiabetic effects of the xanthine derivatives (6, 7) and their chitosan formulations (CS-6, CS-7). Xanthine derivative 6 showed a high antiradical scavenging effect (DPPH remaining=41.78%). It also reduced the glucose blood level with 59.30% and recorded level of glycosylated hemoglobin was 4.53%. The effect of its chitosan formulation (CS-6) on the level of blood glucose (114.5mg/dl) was even more intense than the one recorded by pioglitazone (148.5mg/dl) when used as standard antidiabetic drug. These results demonstrated the potential application of xanthine derivative 6 and its chitosan formulation (CS-6) in the treatment of the diabetes mellitus syndrome.


Assuntos
Quitosana/química , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/química , Xantinas/química , Animais , Portadores de Fármacos , Avaliação Pré-Clínica de Medicamentos , Hipoglicemiantes/uso terapêutico , Espectroscopia de Ressonância Magnética , Camundongos , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Xantinas/uso terapêutico
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