Fabrication of a 3D Printed PCL Nerve Guide: In Vitro and In Vivo Testing

Abstract Background Aspiration testing before filler injection is controversial. Some believe that aspiration can help prevent inadvertent intravascular injection, while others cite false-negative results and question its value given that the needle position always changes somewhat during injection procedures. Objectives To test the relation of false-negative results to the viscosity of the material within the needle lumen and determine whether a less viscous material within the needle lumen could decrease the incidence of false-negative results. Methods In vitro aspiration tests were performed using 30-G and 27-G needle gauges, two cross-linked hyaluronic acid fillers, normal saline bags pressurized at 140 and 10 mmHg to mimic human arterial and venous pressures, and three needle lumen conditions (normal saline, air, and filler). Testing was repeated three times under each study condition (72 tests in total). For in vivo correlation, aspiration tests were performed on femoral arteries and central auricular veins in three rabbits (4–5 aspirations per site, 48 tests in total). Results In vitro and in vivo testing using 30-G needles containing filler both showed false-negative results on aspiration testing. In vitro and in vivo testing using needles containing saline or air showed positive findings. Conclusions False-negative results from aspiration testing may be reduced by pre-filling the needle lumen with saline rather than a filler. The pressurized system may help overcome challenges of animal models with intravascular pressures significantly different from those of humans. The adaptability of this system to mimic various vessel pressures may facilitate physiologically relevant studies of vascular complications.

Download Full-text

Effective decellularisation of human saphenous veins for biocompatible arterial tissue engineering applications: Bench optimisation and feasibility in vivo testing

Journal of Tissue Engineering ◽

10.1177/2041731420987529 ◽

2021 ◽

Vol 12 ◽

pp. 204173142098752

Author(s):

Nadiah S Sulaiman ◽

Andrew R Bond ◽

Vito D Bruno ◽

John Joseph ◽

Jason L Johnson ◽

...

Keyword(s):

Tissue Engineering ◽

Mechanical Strength ◽

Vascular Tissue ◽

Sodium Dodecyl ◽

Host Cells ◽

Replacement Model ◽

In Vivo Testing ◽

Vascular Scaffolds

Human saphenous vein (hSV) and synthetic grafts are commonly used conduits in vascular grafting, despite high failure rates. Decellularising hSVs (D-hSVs) to produce vascular scaffolds might be an effective alternative. We assessed the effectiveness of a detergent-based method using 0% to 1% sodium dodecyl sulphate (SDS) to decellularise hSV. Decellularisation effectiveness was measured in vitro by nuclear counting, DNA content, residual cell viability, extracellular matrix integrity and mechanical strength. Cytotoxicity was assessed on human and porcine cells. The most effective SDS concentration was used to prepare D-hSV grafts that underwent preliminary in vivo testing using a porcine carotid artery replacement model. Effective decellularisation was achieved with 0.01% SDS, and D-hSVs were biocompatible after seeding. In vivo xeno-transplantation confirmed excellent mechanical strength and biocompatibility with recruitment of host cells without mechanical failure, and a 50% patency rate at 4-weeks. We have developed a simple biocompatible methodology to effectively decellularise hSVs. This could enhance vascular tissue engineering toward future clinical applications.

Download Full-text

Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽

10.3390/polym13132146 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2146

Author(s):

Jian Guan ◽

Fu-zhen Yuan ◽

Zi-mu Mao ◽

Hai-lin Zhu ◽

Lin Lin ◽

...

Keyword(s):

Tissue Engineering ◽

Elastic Modulus ◽

Chondrogenic Differentiation ◽

Marker Genes ◽

Self Healing ◽

Polyethylene Glycol Diacrylate ◽

3D Microenvironment ◽

3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

Download Full-text

DDEL-12. NANOPARTICLE DELIVERY OF DOXORUBICIN FOR THE TREATMENT OF DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)

Neuro-Oncology ◽

10.1093/neuonc/noaa222.047 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii286-iii286

Author(s):

Caitlin Ung ◽

Maria Tsoli ◽

Jie Liu ◽

Domenico Cassano ◽

Dannielle Upton ◽

...

Keyword(s):

Treatment Strategies ◽

Pediatric Brain Tumors ◽

Diffuse Intrinsic Pontine Glioma ◽

Confocal Imaging ◽

Cell Content ◽

Potent Effect ◽

Orthotopic Mouse Model ◽

In Vivo Testing

Abstract DIPGs are the most aggressive pediatric brain tumors. Currently, the only treatment is irradiation but due to its palliative nature patients die within 12 months. Effective delivery of chemotherapy across the blood-brain barrier (BBB) has been a key challenge for the eradication of this disease. We have developed a novel gold nanoparticle functionalised with human serum albumin (Au-NP, 98.8 ±19 nm) for the delivery of doxorubicin. In this study, we evaluated the cytotoxic efficacy of doxorubicin delivered through gold nanoparticles (Au-NP-Dox). We found that DIPG neurospheres were equally sensitive to doxorubicin and Au-NP-Dox (at equimolar concentration) by alamar blue assay. Colony formation assays demonstrated a significantly more potent effect of Au-NP-Dox compared to doxorubicin alone, while the Au-NP had no effect. Furthermore, western blot analysis indicated increased apoptotic markers cleaved Parp, caspase 3/7 and phosphorylated H2AX in Au-NP-Dox treated DIPG neurospheres. Live cell content and confocal imaging demonstrated significantly higher uptake of Au-NP-Dox compared to doxorubicin alone. Treatment of a DIPG orthotopic mouse model with Au-NP-Dox showed no signs of toxicity with stable weights being maintained during treatment. However, in contrast to the above in vitro findings the in vivo study showed no anti-tumor effect possibly due to poor penetration of Au-NP-Dox into the brain. We are currently evaluating whether efficacy can be improved using measures to open the BBB transiently. This study highlights the need for rigorous in vivo testing of new treatment strategies before clinical translation to reduce the risk of administration of ineffective treatments.

Download Full-text

In vitro and in vivo testing and correlation for oral controlled/ modified release dosage forms. report of the 2nd workshop held December 1988, Washington, DC. U.S.A.

Journal of Controlled Release ◽

10.1016/0168-3659(90)90064-z ◽

1990 ◽

Vol 14 (1) ◽

pp. 95-106 ◽

Cited By ~ 4

Author(s):

Jerome P. Skelly ◽

Gordon L. Amidon ◽

William H. Barr ◽

Leslie Z. Benet ◽

James E. Carter ◽

...

Keyword(s):

Dosage Forms ◽

Washington Dc ◽

Modified Release ◽

In Vivo Testing

Download Full-text

Thrombus Imaging Using 3D Printed Middle Cerebral Artery Model and Preclinical Imaging Techniques: Application to Thrombus Targeting and Thrombolytic Studies

Pharmaceutics ◽

10.3390/pharmaceutics12121207 ◽

2020 ◽

Vol 12 (12) ◽

pp. 1207

Author(s):

Andrea Vítečková Wünschová ◽

Adam Novobilský ◽

Jana Hložková ◽

Peter Scheer ◽

Hana Petroková ◽

...

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Imaging Techniques ◽

Barium Sulphate ◽

Flow Conditions ◽

Preclinical Imaging ◽

Blood Clots ◽

3D Printed

Diseases with the highest burden for society such as stroke, myocardial infarction, pulmonary embolism, and others are due to blood clots. Preclinical and clinical techniques to study blood clots are important tools for translational research of new diagnostic and therapeutic modalities that target blood clots. In this study, we employed a three-dimensional (3D) printed middle cerebral artery model to image clots under flow conditions using preclinical imaging techniques including fluorescent whole-body imaging, magnetic resonance imaging (MRI), and computed X-ray microtomography (microCT). Both liposome-based, fibrin-targeted, and non-targeted contrast agents were proven to provide a sufficient signal for clot imaging within the model under flow conditions. The application of the model for clot targeting studies and thrombolytic studies using preclinical imaging techniques is shown here. For the first time, a novel method of thrombus labeling utilizing barium sulphate (Micropaque®) is presented here as an example of successfully employed contrast agents for in vitro experiments evaluating the time-course of thrombolysis and thus the efficacy of a thrombolytic drug, recombinant tissue plasminogen activator (rtPA). Finally, the proof-of-concept of in vivo clot imaging in a middle cerebral artery occlusion (MCAO) rat model using barium sulphate-labelled clots is presented, confirming the great potential of such an approach to make experiments comparable between in vitro and in vivo models, finally leading to a reduction in animals needed.

Download Full-text

Coagulation under Mild Hypothermia Assessed by Thromboelastometry

Transfusion Medicine and Hemotherapy ◽

10.1159/000513922 ◽

2021 ◽

pp. 1-7

Author(s):

Tobias Nitschke ◽

Philipp Groene ◽

Alice-Christin Acevedo ◽

Tobias Kammerer ◽

Simon T. Schäfer

Keyword(s):

Mild Hypothermia ◽

Onset Time ◽

Rotational Thromboelastometry ◽

Lysis Time ◽

Sample Data ◽

In Vivo Testing ◽

Fibrinolytic Capacity ◽

Clot Formation Time

Introduction: While previous studies have shown a significant impact of extreme hypo- and hyperthermia on coagulation, effects of much more frequently occurring perioperative mild hypothermia are largely unknown. This study therefore aimed to analyze the effects of mild hypothermia using rotational thromboelastometry in vitro. Materials and Methods: Twelve healthy volunteers were included in this study. Standard thromboelastometric tests (EXTEM, INTEM, FIBTEM) were used to evaluate coagulation in vitro at 39, 37, 35.5, 35, and 33°C. Beyond standard thromboelastometric tests, we also evaluated the effects of mild hypothermia on the TPA-test (ClotPro, Enicor GmbH, Munich, Germany), a new test which aims to detect fibrinolytic capacity by adding tissue plasminogen activator to the sample. Data are presented as the median with 25/75th percentiles. Results: Extrinsically activated coagulation (measured by EXTEM) showed a significant increase in clot formation time (CFT; 37°C: 90 s [81/105] vs. 35°C: 109 s [99/126]; p = 0.0002), while maximum clot firmness (MCF) was not significantly reduced. Intrinsically activated coagulation (measured by INTEM) also showed a significant increase in CFT (37°C: 80 s [72/88] vs. 35°C: 94 s [86/109]; p = 0.0002) without significant effects on MCF. Mild hypothermia significantly increased both the lysis onset time (136 s [132/151; 37°C] vs. 162 s [141/228; 35°C], p = 0.0223) and lysis time (208 s [184/297; 37°C] vs. 249 s [215/358; 35°C]; p = 0.0259). Conclusion: This demonstrates that even under mild hypothermia coagulation is significantly altered in vitro. Perioperative temperature monitoring and management are greatly important and can help to prevent mild hypothermia and its adverse effects. Further investigation and in vivo testing of coagulation under mild hypothermia is needed.

Download Full-text

A Comprehensive Study of Osteogenic Calcium Phosphate Silicate Cement: Material Characterization and In Vitro/In Vivo Testing

Advanced Healthcare Materials ◽

10.1002/adhm.201500469 ◽

2015 ◽

Vol 5 (4) ◽

pp. 457-466 ◽

Cited By ~ 10

Author(s):

Tianxing Gong ◽

Zhiqin Wang ◽

Yixi Zhang ◽

Yubiao Zhang ◽

Mingxiao Hou ◽

...

Keyword(s):

Calcium Phosphate ◽

Material Characterization ◽

Cement Material ◽

Phosphate Silicate ◽

In Vivo Testing ◽

Comprehensive Study

Download Full-text

The Development of Protanine-Coated Cellulose Hollow Fibers for Heparin Removal: In Vitro Characterization and in Vivo Testing

Cosmetic and Pharmaceutical Applications of Polymers ◽

10.1007/978-1-4615-3858-5_33 ◽

1991 ◽

pp. 347-370

Author(s):

Jae-Seung Kim ◽

You-Yin Fu ◽

Victor C. Yang

Keyword(s):

Hollow Fibers ◽

In Vitro Characterization ◽

In Vivo Testing

Download Full-text

Development of a Novel 3D Bioprinted In Vitro Nano Bone Model for Breast Cancer Bone Metastasis Study

MRS Proceedings ◽

10.1557/opl.2014.941 ◽

2014 ◽

Vol 1724 ◽

Cited By ~ 1

Author(s):

Benjamin Holmes ◽

Wei Zhu ◽

Lijie Grace Zhang

Keyword(s):

Breast Cancer ◽

Bone Metastasis ◽

Metastatic Breast ◽

Bone Microstructure ◽

Bone Model ◽

Skeletal Complications ◽

3D Printed ◽

Breast Cancer Bone Metastasis

ABSTRACTBreast cancer (BrCa) is the second commonest cause of cancer-related deaths in women. The metastatic breast cancer exhibits a high affinity to bone, leading to debilitating skeletal complications associated with significant morbidity and poor prognosis. Traditional in vitro and in vivo BrCa bone metastasis models contain many inherent limitations with regards to controllability, reproducibility, and flexibility of design. Thus, the objective of this research is to use a 3D bioprinting system and nanomaterials to recreate a biomimetic and tunable bone model suitable for the effective simulation and study of metastatic BrCa invading and colonizing a bone environment. For this purpose, we designed and 3D printed a series of scaffolds, comprised of a bone microstructure and nano hydroxyapatites (nHA, inorganic nano components in bone). The size and geometry of the bone microstructure was varied with 250 and 150 µm pores, in repeating square and hexagon patterns, for a total of four different pore geometries. 3D bioprinted scaffolds were subsequently conjugated with nHA, using an acetylation chemical functionalization process and then characterized by scanning electron microscope (SEM). SEM imaging showed that our designed microfeatures were printable with the predesigned resolutions described above. Imaging further confirmed that acetylation effectively attached nHA to the surface of scaffolds and induced a nanoroughness. Metastatic BrCa cell 4 h adhesion and 1, 3 and 5 day proliferation were investigated in the bone model in vitro. The cell adhesion and proliferation results showed that all scaffolds are cytocompatible for BrCa cell growth; in particular the nHA scaffolds with small hexagonal pores had the highest cell density. Given this data, it can be stipulated that our 3D printed nHA scaffolds may make effective biomimetic environments for studying BrCa bone metastasis.

Download Full-text