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1.
Adv Wound Care (New Rochelle) ; 13(2): 70-82, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37534840

RESUMO

Objective: Hydrolyzed collagen-based matrices are widely used as wound care dressings. Information on the mechanism of action of such dressings is scanty. The objective of this study was to test the effect of a specific hydrolyzed collagen powder (HCP), which is extensively used for wound care management in the United States. Approach: The effects of HCP on resolution of wound inflammation, perfusion, closure, and breaking strength of the repaired skin were studied in an experimental murine model. Results: In early (day 7) inflammatory phase of wound macrophages, HCP treatment boosted phagocytosis and efferocytosis of wound-site macrophages. In these cells, inducible reactive oxygen species were also higher on day (d) 7. HCP treatment potentiated the expression of anti-inflammatory interleukin (IL)-10 cytokine and proangiogenic vascular endothelial growth factor (VEGF) production. Excisional wounds dressed with HCP showed complete closure on day 21, while the control wounds remained open. HCP treatment also demonstrated improved quality of wound healing as marked by the improved breaking strength of the closed wound tissue/repaired skin. Innovation: These data represent first evidence on the mechanism of action of clinically used HCP. Conclusion: HCP dressing favorably influenced both wound inflammation and vascularization. Improved breaking strength of HCP-treated repaired skin lays the rationale for future studies testing the hypothesis that HCP-treated closed wounds would show fewer recurrences.


Assuntos
Colágeno , Fator A de Crescimento do Endotélio Vascular , Camundongos , Animais , Pós/farmacologia , Colágeno/farmacologia , Cicatrização , Bandagens , Inflamação/metabolismo , Perfusão
2.
iScience ; 26(9): 107533, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37636079

RESUMO

Fetal skin achieves scarless wound repair. Dermal fibroblasts play a central role in extracellular matrix deposition and scarring outcomes. Both fetal and gingival wound repair share minimal scarring outcomes. We tested the hypothesis that compared to adult skin fibroblasts, human fetal skin fibroblast diversity is unique and partly overlaps with gingival skin fibroblasts. Human fetal skin (FS, n = 3), gingiva (HGG, n = 13), and mature skin (MS, n = 13) were compared at single-cell resolution. Dermal fibroblasts, the most abundant cluster, were examined to establish a connectome with other skin cells. Annexin1-FPR1 signaling pathway was dominant in both FS as well as HGG fibroblasts and related myeloid cells while scanty in MS fibroblasts. Myeloid-specific FPR1-ORF delivered in murine wound edge using tissue nanotransfection (TNT) technology significantly enhanced the quality of healing. Pseudotime analyses identified the co-existence of an HGG fibroblast subset with FPR1high myeloid cells of fetal origin indicating common underlying biological processes.

3.
Nat Commun ; 14(1): 1129, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36854749

RESUMO

Tissue injury to skin diminishes miR-200b in dermal fibroblasts. Fibroblasts are widely reported to directly reprogram into endothelial-like cells and we hypothesized that miR-200b inhibition may cause such changes. We transfected human dermal fibroblasts with anti-miR-200b oligonucleotide, then using single cell RNA sequencing, identified emergence of a vasculogenic subset with a distinct fibroblast transcriptome and demonstrated blood vessel forming function in vivo. Anti-miR-200b delivery to murine injury sites likewise enhanced tissue perfusion, wound closure, and vasculogenic fibroblast contribution to perfused vessels in a FLI1 dependent manner. Vasculogenic fibroblast subset emergence was blunted in delayed healing wounds of diabetic animals but, topical tissue nanotransfection of a single anti-miR-200b oligonucleotide was sufficient to restore FLI1 expression, vasculogenic fibroblast emergence, tissue perfusion, and wound healing. Augmenting a physiologic tissue injury adaptive response mechanism that produces a vasculogenic fibroblast state change opens new avenues for therapeutic tissue vascularization of ischemic wounds.


Assuntos
Fibroblastos , Pele , Cicatrização , Animais , Humanos , Camundongos , Antagomirs/farmacologia , Antagomirs/uso terapêutico , Fibroblastos/metabolismo , Fibroblastos/fisiologia , Oligonucleotídeos/farmacologia , Pele/metabolismo , Cicatrização/genética , Cicatrização/fisiologia
4.
Mol Ther ; 31(5): 1402-1417, 2023 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-36380587

RESUMO

Extracellular vesicles (EVs) are nanovesicles released by all eukaryotic cells. This work reports the first nanoscale fluorescent visualization of tumor-originating vesicles bearing an angiogenic microRNA (miR)-126 cargo. In a validated experimental model of lethal murine vascular neoplasm, tumor-originating EV delivered its miR-126 cargo to tumor-associated macrophages (TAMs). Such delivery resulted in an angiogenic (LYVE+) change of state in TAM that supported tumor formation. Study of the trafficking of tumor-originating fluorescently tagged EV revealed colocalization with TAM demonstrating uptake by these cells. Ex vivo treatment of macrophages with tumor-derived EVs led to gain of tumorigenicity in these isolated cells. Single-cell RNA sequencing of macrophages revealed that EV-borne miR-126 characterized the angiogenic change of state. Unique gene expression signatures of specific macrophage clusters responsive to miR-126-enriched tumor-derived EVs were revealed. Topical tissue nanotransfection (TNT) delivery of an oligonucleotide comprising an anti-miR against miR-126 resulted in significant knockdown of miR-126 in the tumor tissue. miR-126 knockdown resulted in complete involution of the tumor and improved survival rate of tumor-affected mice. This work identifies a novel tumorigenic mechanism that relies on tumorigenic state change of TAM caused by tumor-originating EV-borne angiomiR. This disease process can be effectively targeted by topical TNT of superficial tumors.


Assuntos
Vesículas Extracelulares , MicroRNAs , Animais , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Macrófagos/metabolismo , Fagocitose , Vesículas Extracelulares/metabolismo
5.
Front Endocrinol (Lausanne) ; 13: 989844, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36568089

RESUMO

Type 2 diabetes mellitus (T2DM) causes peripheral vascular disease because of which several blood-borne factors, including vital nutrients fail to reach the affected tissue. Tissue epigenome is sensitive to chronic hyperglycemia and is known to cause pathogenesis of micro- and macrovascular complications. These vascular complications of T2DM may perpetuate the onset of organ dysfunction. The burden of diabetes is primarily because of a wide range of complications of which nonhealing diabetic ulcers represent a major component. Thus, it is imperative that current research help recognize more effective methods for the diagnosis and management of early vascular injuries. This review addresses the significance of epigenetic processes such as DNA methylation and histone modifications in the evolution of macrovascular and microvascular complications of T2DM.


Assuntos
Diabetes Mellitus Tipo 2 , Angiopatias Diabéticas , Doenças Vasculares , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Angiopatias Diabéticas/genética , Angiopatias Diabéticas/complicações , Epigênese Genética , Metilação de DNA , Doenças Vasculares/complicações
6.
J Clin Invest ; 132(17)2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35819852

RESUMO

An extreme chronic wound tissue microenvironment causes epigenetic gene silencing. An unbiased whole-genome methylome was studied in the wound-edge tissue of patients with chronic wounds. A total of 4,689 differentially methylated regions (DMRs) were identified in chronic wound-edge skin compared with unwounded human skin. Hypermethylation was more frequently observed (3,661 DMRs) in the chronic wound-edge tissue compared with hypomethylation (1,028 DMRs). Twenty-six hypermethylated DMRs were involved in epithelial-mesenchymal transition (EMT). Bisulfite sequencing validated hypermethylation of a predicted specific upstream regulator TP53. RNA-Seq analysis was performed to qualify findings from methylome analysis. Analysis of the downregulated genes identified the TP53 signaling pathway as being significantly silenced. Direct comparison of hypermethylation and downregulated genes identified 4 genes, ADAM17, NOTCH, TWIST1, and SMURF1, that functionally represent the EMT pathway. Single-cell RNA-Seq studies revealed that these effects on gene expression were limited to the keratinocyte cell compartment. Experimental murine studies established that tissue ischemia potently induces wound-edge gene methylation and that 5'-azacytidine, inhibitor of methylation, improved wound closure. To specifically address the significance of TP53 methylation, keratinocyte-specific editing of TP53 methylation at the wound edge was achieved by a tissue nanotransfection-based CRISPR/dCas9 approach. This work identified that reversal of methylation-dependent keratinocyte gene silencing represents a productive therapeutic strategy to improve wound closure.


Assuntos
Metilação de DNA , Transição Epitelial-Mesenquimal , Animais , Ilhas de CpG , DNA , Epigênese Genética , Transição Epitelial-Mesenquimal/genética , Humanos , Camundongos , Ubiquitina-Proteína Ligases/genética
7.
Diabetes ; 71(5): 1149-1165, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35192691

RESUMO

Therapeutic vascular endothelial growth factor (VEGF) replenishment has met with limited success for the management of critical limb-threatening ischemia. To improve outcomes of VEGF therapy, we applied single-cell RNA sequencing (scRNA-seq) technology to study the endothelial cells of the human diabetic skin. Single-cell suspensions were generated from the human skin followed by cDNA preparation using the Chromium Next GEM Single-cell 3' Kit v3.1. Using appropriate quality control measures, 36,487 cells were chosen for downstream analysis. scRNA-seq studies identified that although VEGF signaling was not significantly altered in diabetic versus nondiabetic skin, phospholipase Cγ2 (PLCγ2) was downregulated. The significance of PLCγ2 in VEGF-mediated increase in endothelial cell metabolism and function was assessed in cultured human microvascular endothelial cells. In these cells, VEGF enhanced mitochondrial function, as indicated by elevation in oxygen consumption rate and extracellular acidification rate. The VEGF-dependent increase in cell metabolism was blunted in response to PLCγ2 inhibition. Follow-up rescue studies therefore focused on understanding the significance of VEGF therapy in presence or absence of endothelial PLCγ2 in type 1 (streptozotocin-injected) and type 2 (db/db) diabetic ischemic tissue. Nonviral topical tissue nanotransfection technology (TNT) delivery of CDH5 promoter-driven PLCγ2 open reading frame promoted the rescue of hindlimb ischemia in diabetic mice. Improvement of blood flow was also associated with higher abundance of VWF+/CD31+ and VWF+/SMA+ immunohistochemical staining. TNT-based gene delivery was not associated with tissue edema, a commonly noted complication associated with proangiogenic gene therapies. Taken together, our study demonstrates that TNT-mediated delivery of endothelial PLCγ2, as part of combination gene therapy, is effective in diabetic ischemic limb rescue.


Assuntos
Diabetes Mellitus Experimental , Fator A de Crescimento do Endotélio Vascular , Animais , Diabetes Mellitus Experimental/genética , Células Endoteliais/metabolismo , Membro Posterior/irrigação sanguínea , Isquemia/metabolismo , Camundongos , Músculo Esquelético/metabolismo , Neovascularização Fisiológica/genética , Fosfolipase C gama/genética , Fosfolipase C gama/metabolismo , Fosfolipase C gama/farmacologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fatores de Crescimento do Endotélio Vascular/metabolismo , Fatores de Crescimento do Endotélio Vascular/farmacologia , Fatores de Crescimento do Endotélio Vascular/uso terapêutico , Fator de von Willebrand/metabolismo , Fator de von Willebrand/farmacologia , Fator de von Willebrand/uso terapêutico
8.
ACS Appl Bio Mater ; 2(12): 5460-5491, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-35021544

RESUMO

Silk, a natural biopolymer, has been used clinically as suture material over thousands of years and has received much impetus for a plethora of biomedical applications in the last two decades. Silk protein isolated from both mulberry and nonmulberry silkworm varieties gained recognition as a potential biomaterial owing to its affordability and remarkable physicochemical properties. Molecular studies on the amino acid composition and conformation of silk proteins interpreted in the present review provide a critical understanding of the difference in crystallinity, hydrophobicity, and tensile strength among silkworm silk proteins. Meticulous silk fibroin (SF) isolation procedures and innovative processing techniques to fabricate gamut of two-dimensional (2D) and three-dimensional (3D) matrices including the latest 3D printed scaffolds have led SF for diverse biomedical applications. Crucial factors for clinical success of any biomaterial, including biocompatibility, immune response, and biodegradability, are discussed with particular emphasis on the lesser-known endemic nonmulberry silk varieties, which in recent years have gained considerable attention. The tunable biodegradation and bioresorbable attributes of SF enabled its use in drug delivery systems, thus proving it as an efficient and specific vehicle for controlled drug release and targeted drug delivery. Advancements in fabrication methodologies inspired biomedical researchers to develop SF-based in vitro tissue models mimicking the spatiotemporal arrangement and cellular distribution of native tissue. In vitro tissue models own a unique demand for studying tissue biology, cellular crosstalks, disease modeling, drug designing, and high throughput drug screening applications. Significant progress in silk biomaterial research has evolved into several silk-based healthcare products in the market. Insights of silk-based products assessed in the human clinical trials are presented in this review. Overall, the current review explores the paradigm of the silk structure-function relationship driving silk-based biomaterials toward tissue engineering, drug delivery systems, and in vitro tissue models.

9.
ACS Biomater Sci Eng ; 5(5): 2054-2078, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-33405710

RESUMO

Materials at the nanoscale offer numerous avenues to be explored and exploited in diverse realms. Among others, proteinaceous biomaterials such as silk hold immense prospects in the domain of nanoengineering. Silk offers a unique combination of desirable facets like biocompatibility; extraordinary mechanical properties, such as elongation, elasticity, toughness, and modulus; and tunable biodegradability which are far better than most naturally occurring and engineered materials. Much of these properties are due to the molecular structure of the silk protein and it is self-assembly into hierarchical structures. Taking advantage of the hierarchical assembly, a large number of fabrication strategies have now emerged that allow the tailoring of silk structure of at the nanoscale. Harnessing the favorable properties of silk, such methods offer a promising direction toward producing structurally and functionally optimized silk nanomaterials. This review discusses the critical structure-property relationship in silk that occurs at the nanoscale and also aims to bring out the recent status in the approaches for fabrication, characterization, and the gamut of applications of various silk-based nanomaterials (nanoparticles, nanofibers, and nanocomposites) in the niche of translational research. Harnessing the favorable nanostructure of silk, the review also takes into account the impetus of silk in avant-garde applications such as chemo-biosensing, energy harvesting, microfluidics, and environmental applications.

10.
Biomaterials ; 187: 1-17, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30286320

RESUMO

Islet transplantation is considered the most promising treatment for type 1 diabetes. However, the clinical success is limited by islet dysfunction in long-term culture. In this study, we have utilized the rapid self-gelation and injectability offered by blending of mulberry silk (Bombyx mori) with non-mulberry (Antheraea assama) silk, resulting in a biomimetic hydrogel. Unlike the previously reported silk gelation techniques, the differences in amino acid sequences of the two silk varieties result in accelerated gelation without requiring any external stimulus. Gelation study and rheological assessment depicts tuneable gelation as a function of protein concentration and blending ratio with minimum gelation time. In vitro biological results reveal that the blended hydrogels provide an ideal 3D matrix for primary rat islets. Also, A. assama fibroin with inherent Arg-Gly-Asp (RGD) shows significant influence on islet viability, insulin secretion and endothelial cell maintenance. Furthermore, utility of these hydrogels demonstrate sustained release of Interleukin-4 (IL-4) and Dexamethasone with effective M2 macrophage polarization while preserving islet physiology. The immuno-informed hydrogel demonstrates local modulation of inflammatory responses in vivo. Altogether, the results exhibit promising attributes of injectable silk hydrogel and the utility of non-mulberry silk fibroin as an alternative biomaterial for islet encapsulation.


Assuntos
Materiais Biomiméticos/química , Hidrogéis/química , Ilhotas Pancreáticas/fisiologia , Macrófagos/efeitos dos fármacos , Mariposas/química , Seda/química , Animais , Materiais Biocompatíveis , Bombyx/química , Linhagem Celular , Sobrevivência Celular , Dexametasona/administração & dosagem , Dexametasona/química , Dexametasona/imunologia , Fibroínas/administração & dosagem , Fibroínas/química , Fibroínas/imunologia , Imunomodulação , Imunossupressores/administração & dosagem , Imunossupressores/química , Imunossupressores/imunologia , Secreção de Insulina , Interleucina-4/administração & dosagem , Interleucina-4/química , Ilhotas Pancreáticas/imunologia , Macrófagos/imunologia , Macrófagos/fisiologia , Ratos , Ratos Wistar , Seda/administração & dosagem , Seda/imunologia , Engenharia Tecidual
11.
ACS Biomater Sci Eng ; 3(10): 2443-2456, 2017 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33445302

RESUMO

Pancreatic islet encapsulation in a 3D scaffolding matrix has achieved limited clinical success due to loss of islet function and cell death, shortly after transplantation. Also, transplant-associated inflammatory responses create an unfavorable microenvironment for islet survival. The current study delineates the development of cell-encapsulating immunomodulatory 3D silk scaffolds as bioartificial pancreas (BAP) systems for sustained insulin release. Insulin producing cells were encapsulated inside silk scaffolds with either alginate or agarose for immunoisolation to augment islet survival and function. The scaffolds were extensively characterized for pore architecture, porosity, swelling index, water uptake, and density. Further, suitability of these scaffolds was assessed through diverse in vitro tests, including cell adherence, viability, proliferation, 3D spheroid like pancreatic structures development, glucose stimulated insulin secretion, and macrophage polarization. Rat insulinoma (RIN-5) cells were metabolically active within the macroencapsulates and proliferated up to 2.5-fold over 5 weeks in culture. Cultured cells formed 3D islet-like spheroids spontaneously. Primary islets maintained their function in macroencapsulates with enhanced glucose stimulation index when compared to nonencapsulated islets, 1.2 vs 1.7. RT-qPCR and immunohistochemistry results supported the results obtained from glucose challenge assay. Controlled release profiles of anti-inflammatory cytokine interleukine-4 (IL-4) and dexamethasone evinced their prospective application in reducing local foreign body response and immunosuppression. Released IL-4 was biologically active and polarized M0 macrophages to the M2 phenotype, advocating immunosuppressive function. Reduced inflammatory responses illustrated the biocompatibility of these scaffolds. In conclusion, this novel biomaterial system was successfully used to encapsulate insulin-producing cells with enhanced cell functions. Further development of the system may have potential BAP applications.

12.
Faraday Discuss ; 196: 71-90, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-27942653

RESUMO

The inner filter effect due to self-quenching dominates the normal emission of dyes at higher concentrations, which would limit their applications. Since normal emission was also observed with aggregation induced emission enhancement (AIEE) active excited state intramolecular proton transfer (ESIPT) exhibiting molecules, two new molecules are synthesized and studied to obtain normal emission free AIEE. The molecules are 4-(3-(benzo[d]thiazol-2-yl)-5-tert-butyl-4-hydroxybenzyl)-2-(benzo[d]thiazol-2-yl)-6-tert-butyl phenol (bis-HPBT) and its oxazole analogue (bis-HPBO). Of these molecules, bis-HPBT, which is weakly fluorescent in tetrahydrofuran solution, shows a sudden high enhancement in fluorescence upon addition of 70% water due to the formation of aggregates. Though the normal emission is also observed in tetrahydrofuran, it is completely eliminated in the aggregates, and the aggregates display exclusive tautomer emission. However, bis-HPBO does not emit such an exclusive tautomer emission in the water/tetrahydrofuran mixture. The enhancement in the fluorescence quantum yield of bis-HPBT in 70% water is ∼300 times higher than that in tetrahydrofuran. The modulated molecular structure of bis-HPBT is the cause of this outstanding AIEE. The observation of almost exclusive tautomer emission is a new additional advantage of AIEE from bis-HPBT over other ESIPT molecules. Since the tautomer emission is highly Stokes shifted, no overlap with the absorption spectrum occurs and therefore, the inner filter effect is averted. The aggregated structure acts as a good fluorescence chemosensor for metal ions as well as anions. The aggregated structure is cell permeable and can be used for cell imaging.

13.
ACS Appl Mater Interfaces ; 8(45): 30797-30810, 2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-27783501

RESUMO

Composite biomaterials as artificial bone graft materials are pushing the present frontiers of bioengineering. In this study, a biomimetic, osteoconductive tricomposite scaffold made of hydroxyapatite (HA) embedded in non-mulberry Antheraea assama (A. assama) silk fibroin fibers and its fibroin solution is explored for its osteogenic potential. Scaffolds were physico-chemically characterized for morphology, porosity, secondary structure conformation, water retention ability, biodegradability, and mechanical property. The results revealed a ∼5-fold increase in scaffold compressive modulus on addition of HA and silk fibers to liquid silk as compared to pure silk scaffolds while maintaining high scaffold porosity (∼90%) with slower degradation rates. X-ray diffraction (XRD) results confirmed deposition of HA crystals on composite scaffolds. Furthermore, the crystallite size of HA within scaffolds was strongly regulated by the intrinsic physical cues of silk fibroin. Fourier transform infrared (FTIR) spectroscopy studies indicated strong interactions between HA and silk fibroin. The fabricated tricomposite scaffolds supported enhanced cellular viability and function (ALP activity) for both MG63 osteosarcoma and human bone marrow stem cells (hBMSCs) as compared to pure silk scaffolds without fiber or HA addition. In addition, higher expression of osteogenic gene markers such as collagen I (Col-I), osteocalcin (OCN), osteopontin (OPN), and bone sialoprotein (BSP) further substantiated the applicability of HA composite silk scaffolds for bone related applications. Immunostaining studies confirmed localization of Col-I and BSP and were in agreement with real-time gene expression results. These findings demonstrate the osteogenic potential of developed biodegradable tricomposite scaffolds with the added advantage of the affordability of its components as bone graft substitute materials.


Assuntos
Seda/química , Materiais Biocompatíveis , Biomimética , Fibroínas , Humanos , Porosidade , Engenharia Tecidual , Alicerces Teciduais
14.
ACS Appl Mater Interfaces ; 8(43): 29310-29322, 2016 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-27726371

RESUMO

Macrophages, the key players in immunoregulation, are actively involved in tissue remodelling and vascularization. Recent advances in tissue engineering and regenerative medicine illustrate the importance of "immuno-informed" biomaterials to regulate the microenvironment of biomedical implants. In the current study, silk-based 3D hydrogels were utilized to regulate cytokine delivery for macrophage, a type of immune cell, differentiation and polarization. Three different hydrogel variants, silk-poly(ethylene glycol) (PEG) (SP), silk-horseradish peroxidase (HRP) (SH) and silk-sonicated (SS) hydrogels were studied. Hydrogels were loaded with the M1 and M2 polarizing cytokines interferon-γ (IFN-γ) and interleukin-4 (IL-4), respectively. Functional cytokine release and macrophage polarization studies were conducted using three cytokine exposure approaches: only cytokine encapsulation (macrophage in culture well), only macrophage encapsulation (cytokine in culture media) and cytokine with macrophage encapsulation. The extent of macrophage polarization by cytokine-eluting and macrophage-encapsulating hydrogels was investigated using gene expression analysis for C-C chemokine receptor 7 (CCR7), Interleukin-1 beta (IL-1ß), cluster of differentiation 206 (CD206) and cluster of differentiation 209 (CD209). The released cytokines polarized macrophages from an M0 phenotype to an M1/M2 phenotype. Also, lineage committed M1/M2 macrophages could be "switched" to their M2/M1 counterparts (M1-to-M2 or M2-to-M1 transition) exhibiting their well-established plasticity. When macrophages were encapsulated in hydrogels, polarization could be induced to the lineage committed M1 or M2 phenotypes either in polarizing media or when coencapsulated with cytokines. Through this study, silk hydrogels demonstrated utility as a novel system for focal delivery of cytokines and macrophages as "immuno-informed" 3D silk-biomaterials.


Assuntos
Materiais Biocompatíveis/química , Citocinas , Interferon gama , Macrófagos , Seda
15.
Mater Sci Eng C Mater Biol Appl ; 69: 1167-74, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612814

RESUMO

Composite nanofibrous membranes based on sol-gel derived 45SiO2 24.5CaO 24.5 Na2O 6 P2O5 (bioglass, BG) and 43SiO2 24.5CaO 24.5 Na2O 6 P2O5 2Fe2O3 (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application.


Assuntos
Cerâmica/química , Vidro/química , Nanofibras/química , Álcool de Polivinil/química , Alicerces Teciduais/química , Fosfatase Alcalina/metabolismo , Regeneração Óssea/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Géis/química , Humanos , Magnetismo , Microscopia de Fluorescência , Nanofibras/toxicidade , Engenharia Tecidual , Viscosidade
16.
ACS Appl Mater Interfaces ; 8(25): 15874-88, 2016 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-27269821

RESUMO

Autologous graft replacement as a strategy to treat diseased peripheral small diameter (≤6 mm) blood vessel is often challenged by prior vein harvesting. To address this issue, we fabricated native-tissue mimicking multilayered small diameter vascular graft (SDVG) using mulberry (Bombyx mori) and Indian endemic non-mulberry (Antheraea assama and Philosamia ricini) silk. Patterned silk films were fabricated on microgrooved PDMS mold, casted by soft lithography. The biodegradable patterned film templates with aligned cell sheets were rolled onto an inert mandrel to mimic vascular conduit. The hemocompatible and mechanically strong non-mulberry films with RGD motif supported ∼1.2 folds greater proliferation of vascular cells with aligned anchorage. Elicitation of minimal immune response on subcutaneous implantation of the films in mice was complemented by ∼45% lower TNF α secretion by in vitro macrophage culture post 7 days. Pattern-induced alignment favored the functional contractile phenotype of smooth muscle cells (SMCs), expressing the signature markers-calponin, α-smooth muscle actin (α-SMA), and smooth muscle myosin heavy chain (SM-MHC). Endothelial cells (ECs) exhibited a typical punctuated pattern of von Willebrand factor (vWF). Deposition of collagen and elastin by the SMCs substantiated the aptness of the graft with desired biomechanical attributes. Furthermore, the burst strength of the fabricated conduit was in the range of ∼915-1260 mmHg, a prerequisite to withstand physiological pressure. This novel fabrication approach may eliminate the need of maturation in a pulsatile bioreactor for obtaining functional cellular phenotype. This work is thereby an attestation to the immense prospects of exploring non-mulberry silk for bioengineering a multilayered vascular conduit similar to a native vessel in "form and function", befitting for in vivo transplantation.


Assuntos
Implantes Experimentais , Miócitos de Músculo Liso/efeitos dos fármacos , Seda/farmacologia , Engenharia Tecidual/métodos , Alicerces Teciduais/normas , Animais , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/normas , Colágeno/metabolismo , Camundongos , Morus/metabolismo , Mariposas/química , Miócitos de Músculo Liso/citologia , Seda/química , Alicerces Teciduais/química
17.
Photochem Photobiol Sci ; 15(7): 937-48, 2016 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-27334264

RESUMO

In this study, the aggregation induced emission enhancement (AIEE) of 2-(2'-hydroxyphenyl)benzimidazole (HPBI) is reported. To investigate the AIEE process of HPBI, absorption/fluorescence spectroscopy, fluorescence imaging and field emission scanning electron microscopy were employed. A comparative study with 2-phenylbenzimidazole (PBI) divulges the significance of the hydroxyl group in the AIEE process. Further, molecular dynamics simulations have been carried out with explicit solvent molecules to follow the aggregation process of HPBI with time. The obtained molecular dynamics simulation results not only predicted the formation of aggregates but also provided detailed insight and information on the molecular interactions. The cellular studies showed aggregates yield higher fluorescence in the visible region inside HeLa cells in comparison to monomeric compounds which failed to exhibit any visible fluorescence inside the cell. The obtained aggregates were further found to be biocompatible and therefore can be used for bio-imaging applications.


Assuntos
Benzimidazóis/química , Benzimidazóis/metabolismo , Benzimidazóis/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Simulação de Dinâmica Molecular , Solventes/química , Espectrometria de Fluorescência , Raios Ultravioleta
18.
J Biomater Sci Polym Ed ; 27(3): 247-62, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26573740

RESUMO

Cross-linked polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) composite nanofibrous membranes have been prepared by electrospinning. Mechanical properties of the membranes improved significantly with PVP addition. PVP improved hydrophilicity and sustainable degradation of the membranes. Biocompatibility of the membranes was assessed by in vitro culture of native skin cells (L929 fibroblast and HaCaT keratinocytes). Tests showed sustained release of the antibiotic ciprofloxacin hydrochloride monohydrate by the membranes. Further, zone of inhibition study against Staphylococcus aureus growth demonstrated protective action against external pathogenic microbes. These studies show these simple PVA-PVP nanofibrous membranes are promising interactive antibiotic-eluting wound dressing materials.


Assuntos
Bandagens , Nanofibras , Álcool de Polivinil , Povidona , Animais , Antibacterianos/administração & dosagem , Antibacterianos/farmacocinética , Linhagem Celular , Proliferação de Células , Ciprofloxacina/administração & dosagem , Ciprofloxacina/farmacocinética , Condutividade Elétrica , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Humanos , Queratinócitos/efeitos dos fármacos , Queratinócitos/fisiologia , Teste de Materiais , Camundongos , Nanofibras/química , Álcool de Polivinil/química , Povidona/química , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/fisiopatologia , Staphylococcus aureus , Viscosidade , Água/química , Cicatrização/efeitos dos fármacos , Cicatrização/fisiologia
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