Alkali treatment facilitates functional nano-hydroxyapatite coating of 3D printed polylactic acid scaffolds

Chen, Weitong; Nichols, Luke; Brinkley, Frank; Bohna, Kelson; Tian, Wenmeng; Priddy, Matthew W.; Priddy, Lauren B.

doi:10.1016/j.msec.2020.111686

Cited by 53 publications

(44 citation statements)

References 43 publications

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“…The use of material extrusion techniques offers the possibility of obtaining PLA scaffolds with controlled pore size and porosity so that the characteristics of the 3D construct can be tailored to the patient and target tissue. The precision in the design and manufacturing of the scaffolds is severely compromised when applying an alkali surface treatment, as the weight loss of the samples will surely be accompanied by changes in the struts’ dimensions, microporosity, and mechanical properties of the structure [ 21 ]. The percentage of weight loss for scaffolds treated with NaOH depends on the concentration of the solution, being in this study around 2% for 0.2 N NaOH solutions and more than 5% for 1 N NaOH treatment (as illustrated in Table 1 ).…”

Section: Discussionmentioning

confidence: 99%

“…Carboxyl groups incorporated into the PLA surface lead to an enhancement of roughness and wettability [ 14 , 16 ], serving as anchoring points for biological substances [ 17 , 18 ] and promoting the cell adhesion and proliferation processes [ 19 , 20 ]. The modifications generated by alkali treatment methods depend strongly on the concentration of the solution used, and the treatment time could affect the surface morphology and mechanical properties of the scaffolds [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

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On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

2021

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Surface modification of 3D-printed PLA structures is a major issue in terms of increasing the biofunctionality and expanding the tissue engineering applications of these parts. In this paper, different exposure times were used for low-pressure oxygen plasma applied to PLA 3D-printed scaffolds. Alkali surface treatments were also evaluated, aiming to compare the modifications introduced on the surface properties by each strategy. Surface-treated samples were characterized through the quantification of carboxyl groups, energy-dispersive X-ray spectroscopy, water contact angle measurements, and differential scanning calorimetry analysis. The change in the surface properties was studied over a two-week period. In addition, an enzymatic degradation analysis was carried out to evaluate the effect of the surface treatments on the degradation profile of the 3D structures. The physicochemical characterization results suggest different mechanism pathways for each type of treatment. Alkali-treated scaffolds showed a higher concentration of carboxyl groups on their surface, which enhanced the enzymatic degradation rate, but were also proven to be more aggressive towards 3D-printed structures. In contrast, the application of the plasma treatments led to an increased hydrophilicity of the PLA surface without affecting the bulk properties. However, the changes on the properties were less steady over time.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

2021

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“…In the last decade, PLA-based scaffolds produced by 3D printing technology had widespread uses in bone tissue engineering owing to their good biocompatibility, biodegradability, and printability ( Kao et al, 2015 ; Hassanajili et al, 2019 ; Yao et al, 2020 ). However, the major drawbacks of PLA, such as hydrophobicity, slow degradation behavior, and lack of abundant cell-recognition functional group, limit further clinical application ( Chen et al, 2021a ). Until recently, researchers have proposed various approaches to optimize the osteogenic properties of the PLA to promote adequate cell interactions with its surface ( Feng et al, 2018 ; Shuai et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Biomimetic, mussel-inspired surface modification of 3D-printed biodegradable polylactic acid scaffolds with nano-hydroxyapatite for bone tissue engineering

Chi

Cui

et al. 2022

Front. Bioeng. Biotechnol.

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Polylactic acid (PLA) has been widely used as filaments for material extrusion additive manufacturing (AM) to develop patient-specific scaffolds in bone tissue engineering. Hydroxyapatite (HA), a major component of natural bone, has been extensively recognized as an osteoconductive biomolecule. Here, inspired by the mussel-adhesive phenomenon, in this study, polydopamine (PDA) coating was applied to the surface of 3D printed PLA scaffolds (PLA@PDA), acting as a versatile adhesive platform for immobilizing HA nanoparticles (nHA). Comprehensive analyses were performed to understand the physicochemical properties of the 3D-printed PLA scaffold functionalized with nHA and PDA for their potent clinical application as a bone regenerative substitute. Scanning electron microscopy (SEM) and element dispersive X-ray (EDX) confirmed a successful loading of nHA particles on the surface of PLA@PDA after 3 and 7 days of coating (PLA@PDA-HA3 and PLA@PDA-HA7), while the surface micromorphology and porosity remain unchanged after surface modification. The thermogravimetric analysis (TGA) showed that 7.7 % and 12.3% mass ratio of nHA were loaded on the PLA scaffold surface, respectively. The wettability test indicated that the hydrophilicity of nHA-coated scaffolds was greatly enhanced, while the mechanical properties remained uncompromised. The 3D laser scanning confocal microscope (3DLS) images revealed that the surface roughness was significantly increased, reaching Sa (arithmetic mean height) of 0.402 μm in PLA@PDA-HA7. Twenty-eight days of in-vitro degradation results showed that the introduction of nHA to the PLA surface enhances its degradation properties, as evidenced by the SEM images and weight loss test. Furthermore, a sustainable release of Ca2+ from PLA@PDA-HA3 and PLA@PDA-HA7 was recorded, during the degradation process. In contrast, the released hydroxyl group of nHA tends to neutralize the local acidic environments, which was more conducive to osteoblastic differentiation and extracellular mineralization. Taken together, this facile surface modification provides 3D printed PLA scaffolds with effective bone regenerative properties by depositing Ca2+ contents, improving surface hydrophilicity, and enhancing the in-vitro degradation rate.

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“…Different surface treatments were incorporated to reduce the time duration of the biomineralization process in SBF and deposit an apatite layer. These treatments include silicate 166 , ammonia alkali 167 , and grafting of citric acid-polyethylene imine 168 . For example, our group reported the surface treatment with citric acid-polyethylene imine reduced the time required to was not observed in vivo in any group (Figure 4) 169 .…”

Section: Ha Coating Onmentioning

confidence: 99%

Surface engineering of biodegradable implants: emerging trends in bioactive ceramic coatings and mechanical treatments

2021

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Alkali treatment facilitates functional nano-hydroxyapatite coating of 3D printed polylactic acid scaffolds

Cited by 53 publications

References 43 publications

On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

On the Effectiveness of Oxygen Plasma and Alkali Surface Treatments to Modify the Properties of Polylactic Acid Scaffolds

Biomimetic, mussel-inspired surface modification of 3D-printed biodegradable polylactic acid scaffolds with nano-hydroxyapatite for bone tissue engineering

Surface engineering of biodegradable implants: emerging trends in bioactive ceramic coatings and mechanical treatments

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