The field of biomaterials has advanced significantly in the past decade.With the growing need for high-throughput manufacturing and screening,the need for modular materials that enable streamlined fabrication and anal...The field of biomaterials has advanced significantly in the past decade.With the growing need for high-throughput manufacturing and screening,the need for modular materials that enable streamlined fabrication and analysis of tissue engineering and drug delivery schema has emerged.Microparticles are a powerful platform that have demonstrated promise in enabling these technologies without the need to modify a bulk scaffold.This building block paradigm of using microparticles within larger scaffolds to control cell ratios,growth factors and drug release holds promise.Gelatin microparticles(GMPs)are a well-established platform for cell,drug and growth factor delivery.One of the challenges in using GMPs though is the limited ability to modify the gelatin post-fabrication.In the present work,we hypothesized that by thiolating gelatin before microparticle formation,a versatile platform would be created that preserves the cytocompatibility of gelatin,while enabling post-fabrication modification.The thiols were not found to significantly impact the physicochemical properties of the microparticles.Moreover,the thiolated GMPs were demonstrated to be a biocompatible and robust platform for mesenchymal stem cell attachment.Additionally,the thiolated particles were able to be covalently modified with a maleimide-bearing fluorescent dye and a peptide,demonstrating their promise as a modular platform for tissue engineering and drug delivery applications.展开更多
Extrusion bioprinting is a popular method for fabricating tissue engineering scaffolds because of its potential to rapidly produce complex,bioactive or cell-laden scaffolds.However,due to the relatively high viscosity...Extrusion bioprinting is a popular method for fabricating tissue engineering scaffolds because of its potential to rapidly produce complex,bioactive or cell-laden scaffolds.However,due to the relatively high viscosity required to maintain shape fidelity during printing,many extrusion-based inks lack the ability to achieve precise structures at scales lower than hundreds of micrometers.In this work,we present a novel poly(N-isopropylacrylamide)(PNIPAAm)-based ink and poloxamer support bath system that produces precise,multi-layered structures on the tens of micrometers scale.The support bath maintains the structure of the ink in a hydrated,heated environment ideal for cell culture,while the ink undergoes rapid thermogelation followed by a spontaneous covalent crosslinking reaction.Through the combination of the PNIPAAm-based ink and poloxamer bath,this system was able to produce hydrogel scaffolds with uniform fibers possessing diameters tunable from 80 to 200μm.A framework of relationships between several important printing factors involved in maintaining support and thermogelation was also elucidated.As a whole,this work demonstrates the ability to produce precise,acellular and cell-laden PNIPAAm-based scaffolds at high-resolution and contributes to the growing body of research surrounding the printability of extrusion-based bioinks with support baths.展开更多
Thermogelling hydrogels,such as poly(N-isopropylacrylamide)[P(NiPAAm)],provide tunable constructs leveraged in many regenerative biomaterial applications.Recently,our lab developed the crosslinker poly(glycolic acid)-...Thermogelling hydrogels,such as poly(N-isopropylacrylamide)[P(NiPAAm)],provide tunable constructs leveraged in many regenerative biomaterial applications.Recently,our lab developed the crosslinker poly(glycolic acid)-poly(ethylene glycol)-poly(glycolic acid)-di(but-2-yne-1,4-dithiol),which crosslinks P(NiPAAm-co-glycidyl methacrylate)via thiol-epoxy reaction and can be functionalized with azide-terminated peptides via alkyne-azide click chemistry.This study’s aim was to evaluate the impact of peptides on the physicochemical properties of the hydrogels.The physicochemical properties of the hydrogels including the lower critical solution temperature,crosslinking times,swelling,degradation,peptide release and cytocompatibility were evaluated.The gels bearing peptides increased equilibrium swelling indicating hydrophilicity of the hydrogel components.Comparable sol fractions were found for all groups,indicating that inclusion of peptides does not impact crosslinking.Moreover,the inclusion of a matrix metalloproteinase-sensitive peptide allowed elucidation of whether release of peptides from the network was driven by hydrolysis or enzymatic cleavage.The hydrophilicity of the network determined by the swelling behavior was demonstrated to be the most important factor in dictating hydrogel behavior over time.This study demonstrates the importance of characterizing the impact of additives on the physicochemical properties of hydrogels.These characteristics are key in determining design considerations for future in vitro and in vivo studies for tissue regeneration.展开更多
基金This work was supported by the National Institutes of Health(R01 AR068073 and P41 EB023833)H.A.P.,M.M.S.and E.Y.J.acknowledge support from the National Science Foundation Graduate Research Fellowship Program.M.M.S.also acknowledges support from the Ford Doctoral Fellowship Program.E.W.received support from Ruth L.Kirschstein Fellowship and the National Institute of Dental and Craniofacial Research(F31 DE027586).
文摘The field of biomaterials has advanced significantly in the past decade.With the growing need for high-throughput manufacturing and screening,the need for modular materials that enable streamlined fabrication and analysis of tissue engineering and drug delivery schema has emerged.Microparticles are a powerful platform that have demonstrated promise in enabling these technologies without the need to modify a bulk scaffold.This building block paradigm of using microparticles within larger scaffolds to control cell ratios,growth factors and drug release holds promise.Gelatin microparticles(GMPs)are a well-established platform for cell,drug and growth factor delivery.One of the challenges in using GMPs though is the limited ability to modify the gelatin post-fabrication.In the present work,we hypothesized that by thiolating gelatin before microparticle formation,a versatile platform would be created that preserves the cytocompatibility of gelatin,while enabling post-fabrication modification.The thiols were not found to significantly impact the physicochemical properties of the microparticles.Moreover,the thiolated GMPs were demonstrated to be a biocompatible and robust platform for mesenchymal stem cell attachment.Additionally,the thiolated particles were able to be covalently modified with a maleimide-bearing fluorescent dye and a peptide,demonstrating their promise as a modular platform for tissue engineering and drug delivery applications.
基金the National Institutes of Health(P41 EB023833)the National Science Foundation Graduate Research Fellowship Program(A.M.N.)for financial supportsupported by a Rubicon postdoctoral fellowship from the Dutch Research Council(NWO,Project No.019.182 EN.004).
文摘Extrusion bioprinting is a popular method for fabricating tissue engineering scaffolds because of its potential to rapidly produce complex,bioactive or cell-laden scaffolds.However,due to the relatively high viscosity required to maintain shape fidelity during printing,many extrusion-based inks lack the ability to achieve precise structures at scales lower than hundreds of micrometers.In this work,we present a novel poly(N-isopropylacrylamide)(PNIPAAm)-based ink and poloxamer support bath system that produces precise,multi-layered structures on the tens of micrometers scale.The support bath maintains the structure of the ink in a hydrated,heated environment ideal for cell culture,while the ink undergoes rapid thermogelation followed by a spontaneous covalent crosslinking reaction.Through the combination of the PNIPAAm-based ink and poloxamer bath,this system was able to produce hydrogel scaffolds with uniform fibers possessing diameters tunable from 80 to 200μm.A framework of relationships between several important printing factors involved in maintaining support and thermogelation was also elucidated.As a whole,this work demonstrates the ability to produce precise,acellular and cell-laden PNIPAAm-based scaffolds at high-resolution and contributes to the growing body of research surrounding the printability of extrusion-based bioinks with support baths.
基金supported by the National Institutes of Health(R01 AR068073 and P41 EB023833).
文摘Thermogelling hydrogels,such as poly(N-isopropylacrylamide)[P(NiPAAm)],provide tunable constructs leveraged in many regenerative biomaterial applications.Recently,our lab developed the crosslinker poly(glycolic acid)-poly(ethylene glycol)-poly(glycolic acid)-di(but-2-yne-1,4-dithiol),which crosslinks P(NiPAAm-co-glycidyl methacrylate)via thiol-epoxy reaction and can be functionalized with azide-terminated peptides via alkyne-azide click chemistry.This study’s aim was to evaluate the impact of peptides on the physicochemical properties of the hydrogels.The physicochemical properties of the hydrogels including the lower critical solution temperature,crosslinking times,swelling,degradation,peptide release and cytocompatibility were evaluated.The gels bearing peptides increased equilibrium swelling indicating hydrophilicity of the hydrogel components.Comparable sol fractions were found for all groups,indicating that inclusion of peptides does not impact crosslinking.Moreover,the inclusion of a matrix metalloproteinase-sensitive peptide allowed elucidation of whether release of peptides from the network was driven by hydrolysis or enzymatic cleavage.The hydrophilicity of the network determined by the swelling behavior was demonstrated to be the most important factor in dictating hydrogel behavior over time.This study demonstrates the importance of characterizing the impact of additives on the physicochemical properties of hydrogels.These characteristics are key in determining design considerations for future in vitro and in vivo studies for tissue regeneration.
