Fluorescent, online monitoring of PLGA degradation for regenerative medicine applications

Bardsley, Katie; Wimpenny, Ian; Yang, Ying; Haj, Alicia J. El

doi:10.1039/c6ra04690h

Cited by 14 publications

(11 citation statements)

References 27 publications

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“…It is desirable that materials implanted into bone defects degrade at a suitable rate to allow new matrix deposition, mineralisation and vascular ingrowth to take place. The degradation of PLGA in this study supports previous observations using these scaffolds (Bardsley et al, 2016 ). PLGA degradation rate may be modified by adjusting internal factors; ratio of glycolic vs. lactic portion, porosity, size etc (Lu et al, 1999 ; Wu and Ding, 2005 ; Makadia and Siegel, 2011 ) and external factors; local pH, mechanical loading, temperature (Middleton and Tipton, 2000 ; Grayson et al, 2005 ; Yang et al, 2010 ).…”

Section: Discussionsupporting

confidence: 92%

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A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair

Moser

Bardsley

Haj

et al. 2018

Front. Bioeng. Biotechnol.

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Biomaterials development for bone repair is currently hindered by the lack of physiologically relevant in vitro testing systems. Here we describe the novel use of a bi-directional perfusion bioreactor to support the long term culture of human bone marrow stromal cells (BMSCs) differentiated on polylactic co-glycolic acid (PLGA). Primary human BMSCs were seeded onto porous PLGA scaffolds and cultured in static vs. perfusion culture conditions for 21 days in osteogenic vs. control media. PLGA scaffolds were osteoconductive, supporting a mature osteogenic phenotype as shown by the upregulation of Runx2 and the early osteocyte marker E11. Perfusion culture enhanced the expression of osteogenic genes Osteocalcin and Osteopontin. Extracellular matrix deposition and mineralisation were spatially regulated within PLGA scaffolds in a donor dependant manner. This, together with the observed upregulation of Collagen type X suggested an environment permissive for the study of differentiation pathways associated with both intramembranous and endochondral ossification routes of bone healing. This culture system offers a platform to assess BMSC behavior on candidate biomaterials under physiologically relevant conditions. Use of this system may improve our understanding of the environmental cues orchestrating BMSC differentiation and enable fine tuning of biomaterial design as we develop tissue-engineered strategies for bone regeneration.

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Section: Discussionsupporting

confidence: 92%

“…The poly(lactic-co-glycolic acid) scaffolds with a 50:50 ratio lactic acid vs. glycolic acid (PLGA 50:50) were produced as previously described (Bardsley et al, 2016 ). The scaffolds were 8 mm in diameter, 2 mm height with a pore size of 100–150 μm (Figure 1D ).…”

Section: Methodsmentioning

confidence: 99%

A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair

Moser

Bardsley

Haj

et al. 2018

Front. Bioeng. Biotechnol.

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“…This approach was successfully extended to hyaluronan hydrogels for tissue engineering applications, 13 thermosensitive PEGylated polyester hydrogel, 14 and poly(lactide- co -glycolide) [PLGA] degradation for regenerative medicine applications. 15 Also, fluorescence resonance energy transfer was implemented to follow the assembly and disassembly of micellar, thermoresponsive hydrogels consisting of triblock copolymers; the use of multiple tags allowed tracing the fate of the materials both in vitro and in vivo and at nano- and molecular levels. 16 Despite the undeniable utility of these approaches, the chemical modification with fluorescent tags may affect the physicochemical properties of the polymer and the biological safety.…”

Section: Introductionmentioning

confidence: 99%

Capturing the Real-Time Hydrolytic Degradation of a Library of Biomedical Polymers by Combining Traditional Assessment and Electrochemical Sensors

et al. 2021

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We have developed an innovative methodology to overcome the lack of techniques for real-time assessment of degradable biomedical polymers at physiological conditions. The methodology was established by combining polymer characterization techniques with electrochemical sensors. The in vitro hydrolytic degradation of a series of aliphatic polyesters was evaluated by following the molar mass decrease and the mass loss at different incubation times while tracing pH and l -lactate released into the incubation media with customized miniaturized electrochemical sensors. The combination of different analytical approaches provided new insights into the mechanistic and kinetics aspects of the degradation of these biomedical materials. Although molar mass had to reach threshold values for soluble oligomers to be formed and specimens’ resorption to occur, the pH variation and l -lactate concentration were direct evidence of the resorption of the polymers and indicative of the extent of chain scission. Linear models were found for pH and released l -lactate as a function of mass loss for the l -lactide-based copolymers. The methodology should enable the sequential screening of degradable polymers at physiological conditions and has potential to be used for preclinical material’s evaluation aiming at reducing animal tests.

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“…This suggests the involvement of the -N=C=S moiety in the binding, as reported in the literature for analogous systems, and that the concentration of free dye is low. 44,45,46 In the 1 H NMR experiments on pure RITC (spectrum reported in Fig. 4a) sharp and well resolved resonances of the aromatic protons (6.8-7.4 ppm) as well as of the ethyl group protons (1.05 and 3.5 ppm) can be observed.…”

Section: Au@ritc Nps Synthesis and Characterizationsmentioning

confidence: 93%

Gold nanoparticles functionalized by rhodamine B isothiocyanate: A new tool to control plasmonic effects

Fratoddi

Cartoni

Venditti

et al. 2018

Journal of Colloid and Interface Science

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Gold nanoparticles with an average diameter of 10 nm, functionalized by the dye molecule rhodamine B isothiocyanate, have been synthesized. The resulting material has been extensively characterized both chemically, to investigate the bonding between the dye molecules and the nanoparticles, and physically, to understand the details of the aggregation induced by interaction between dye molecules on different nanoparticles. The plasmonic response of the system has been further characterized by measurement and theoretical simulation of the static UV-Vis extinction spectra of the aggregates produced following different synthesis procedures. The model parameters used in the simulation gave further useful information on the aggregation and its relationship to the plasmonic response. Finally, we investigated the time dependence of the plasmonic effects of the nanoparticles and fluorescence of the dye molecule using an ultrafast pump-probe optical method. By modulating the quantity of dye molecules on the surface of the nanoparticles it was possible to exert fine control over the plasmonic response of nanoparticles.

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Fluorescent, online monitoring of PLGA degradation for regenerative medicine applications

Abstract: Poly(lactic-co-glycolic)acid was chemically modified by covalently binding an isothiocyanate fluorophore to the polymer, allowing for accurate prediction of degradation.

Cited by 14 publications

References 27 publications

A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair

A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair

Capturing the Real-Time Hydrolytic Degradation of a Library of Biomedical Polymers by Combining Traditional Assessment and Electrochemical Sensors

Gold nanoparticles functionalized by rhodamine B isothiocyanate: A new tool to control plasmonic effects

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