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Delivery of Immune Checkpoint Inhibitors Using Nanoparticles
Published in Hala Gali-Muhtasib, Racha Chouaib, Nanoparticle Drug Delivery Systems for Cancer Treatment, 2020
Abdullah Shaito, Houssein Hajj Hassan
Hydrogels exist as a network of water-insoluble polymer chains that sometimes form a colloidal gel when dispersed in a water medium. Hydrogels are photopolymers or copolymers and can be manufactured from natural or synthetic polymeric compounds. Hydrogels can absorb enormous amounts of water or biological fluids to form hydrophilic networks that are similar to biological tissues. Thus, hydrogels have decent biomedical applications; by fine-tuning the physicochemical properties of hydrogels, suitable drug delivery systems can be generated [59, 85].
Sensor-Enabled 3D Printed Tissue-Mimicking Phantoms: Application in Pre-Procedural Planning for Transcatheter Aortic Valve Replacement
Published in Ayman El-Baz, Jasjit S. Suri, Cardiovascular Imaging and Image Analysis, 2018
Kan Wang, Chuck Zhang, Ben Wang, Mani A Vannan, Zhen Qian
3D printing features a high ability for customization, high geometrical complexity, and cost effectiveness in manufacturing cases with low production volume, which is perfectly suited for biomedical applications like prosthetics implants [33], orthopedic implants [7], [34], [35], and tissue/organ printing [8], [36], [37]. Bose et al. did a comprehensive review of cases where additive manufacturing technologies were applied in bone tissue engineering [38]. In some of those cases, multiple types of materials, including ceramics and polymers, were used to tune the mechanical properties of the printed scaffolds. Biglino et al. demonstrated the fabrication of compliant arterial phantoms with PolyJet technology, an additive manufacturing technique that deposits liquid photopolymer layer by layer through orifice jetting and then solidifies by UV exposure [39]. A rubber-like material named TangoPlus (Stratasys Ltd) was used in this study because its mechanical properties are similar to the real tissue. Cloonan et al. did a comparative study on common tissue-mimicking materials and 3D printing materials including TangoPlus with the abdominal aortic aneurysm phantoms [40]. Their results suggested that TangoPlus was a suitable material for modeling arteries in terms of dispensability and it outperformed poly (dimethylsiloxane) (PDMS) Sylgard elastomers that were commonly used in the investment casting process in terms of uniaxial tensile properties.
Small field and radiosurgery dosimetry
Published in Sam Beddar, Luc Beaulieu, Scintillation Dosimetry, 2018
Kamil M. Yenice, David Klein, Dany Theriault
The convenience of self-development and easier handling is somewhat offset by some inherent disadvantages, however. Similar to radiographic film, radiochromic film suffers from inconsistency in response between production batches, from film to film, and across the same film (Hartmann, Martišíková, & Jäkel, 2010). The photopolymerization mechanism is temperature and humidity dependent (Rink, Lewis, Varma, Vitkin, & Jaffray, 2008), and relatively slow-the film may take upwards of days or weeks to fully develop. Furthermore, performing reliable dosimetry with radiochromic film can be relatively complicated (Niroomand-Rad et al., 1998). The precise orientation of the film during irradiation, period of time elapsed between irradiation and scanning, positioning of the film in the scanner (e.g., portrait versus landscape and centered versus offset), the spectral characteristics (i.e., center wavelength and width) of the red, blue, and green channels detected by the scanner, all influence the accuracy of radiochromic film dosimetry to varying degrees (Micke, Lewis, & Yu, 2011). However, even considering the limitations mentioned above, future advances in photopolymer technology may reduce or eliminate the weaknesses of current versions of radiochromic film.
Stereolithography 3D printing technology in pharmaceuticals: a review
Published in Drug Development and Industrial Pharmacy, 2021
Subhash Deshmane, Prakash Kendre, Hitendra Mahajan, Shirish Jain
The choice of photopolymer is of utmost importance in SLA [94,95]. The lack of approval of photosensitive materials by the regulatory authority (the FDA) limits the use of SLA significantly, even though photosensitive materials are used in tissue engineering. During the last decade, a number of photocrosslinkable polymers have been developed. Poly(ethylene glycol) diacrylate (PEGDA) [73,96], poly(2-hydroxyethyl methacrylate) (pHEMA) [97], poly(ethylene glycol) dimethacrylate (PEGDMA) [98,99] and poly(propylene fumarate)/diethyl fumarate (PPF/DEF) [100,101] are examples of photocrosslinkable polymers. Biomedical materials have applications in surgical tools, hearing aids, knee joint appliances and dental appliances [102]. The multiple resins for one build showed patterning with PEG-DMA and PEG-DA with fluorescently labeled dextran, fluorescently labeled bioactive PEG or bioactive PEG in different regions of the scaffold [103]. Complex 3D scaffolds can be fabricated using photocrosslinkable poly(propylene fumarate) (PPF) [104,105], which requires reactive diluents containing significant amounts of non-degradable components. N-vinyl-2-pyrrolidone and diethyl fumarate are used as diluents to reduce the viscosity of the resin during processing [106]. Reconstruction of cranial defects in rabbits is possible because of the ability to produce controlled microstructures [89]. Trimethylene carbonate, polycaprolactone and poly(D,L-lactide) are examples of materials used commonly in tissue engineering [107,108].
Polymethylmethacrylate cranioplasty using low-cost customised 3D printed moulds for cranial defects – a single Centre experience: technical note
Published in British Journal of Neurosurgery, 2019
Krešimir Saša Đurić, Hrvoje Barić, Ivan Domazet, Petra Barl, Niko Njirić, Goran Mrak
Cases were elective cranioplasty patients for reconstruction of large cranial defects, or patients with tumours in which large bony defects were anticipated. All patients underwent a preoperative high-resolution (1.25 mm slices) computed tomography (CT) scan. The CT data of the patients were sent electronically to a printing company and were used to generate 3D models of the defects using free open-source 3D Slicer software (www.slicer.org). The virtual models were then used to produce moulds that were negatives of a 3 mm thick lamina of the outer surface of the skull. Skull defects were reconstructed as mirror images of the contralateral side and moulds were produced from MED 610 material. The material is a rigid, transparent biocompatible photopolymer used for medical and dental models. Images were processed using Solidworks® software (Solidworks Corp., Concord, MA, USA) and the moulds printed using a commercially available outsourced Objet30 OrthoDesk (Stratasys, Ltd., Eden Prairie, MN) 3D printer. The moulds were delivered to our Department a day before the surgery and sterilised in the central sterile services department. Intraoperatively, the mould was wetted with saline, PMMA (Codman cranioplastic kit®, USA) was mixed and evenly spread in the mould cavity, and the mould tightened with screws to obtain a 3 mm thick implant. Edges of the cooled implant were trimmed using a high speed drill as necessary. Finally, the implants were fixed in place using microscrews and microplates. All procedures were performed under general anaesthesia.
3‐D printed spectacles: potential, challenges and the future
Published in Clinical and Experimental Optometry, 2020
Ling Lee, Anthea M Burnett, James G Panos, Prakash Paudel, Drew Keys, Harris M Ansari, Mitasha Yu
Vat photopolymerisation includes printing techniques such as stereolithography and digital light processing. A vat of liquid photopolymer resin is selectively solidified layer‐by‐layer using either UV light, a photon laser, or exposure to heat.2010 As each layer is completed, a platform moves down and the process is repeated. Once complete, the remaining liquid is drained. Digital light processing differs from stereolithography as each layer of liquid resin is exposed to a projector light shaped according to the design and cured all at once, rather than the layer being progressively cured by a laser.2013 Curing an entire layer can reduce printing times; however, resolution is dependent on the projector quality and is likely to be poorer than stereolithography printers.