Inkjet‐Printed Alginate Microspheres as Additional Drug Carriers for Injectable Hydrogels

Abstract

Local delivery of bioactive molecules to the inner ear via diffusion through the round window membrane is becoming an attractive approach to treat sensorineural hearing loss compared to systemic drug administration. Pluronics R (Lutrol F127) are a class of thermosensitive hydrogels that remain liquid prior to injection and rapidly gel under physiological conditions. They are, however, limited to short-term drug release due to rapid hydrolysis in aqueous solution. Therefore, the aim of this study was to investigate an approach, using an ink-jet printing system, to sustain the drug release by incorporating hydrogel microspheres within Lutrol F127. Various concentrations of Lutrol F127 and calcium chloride (CaCl 2 ) were examined by rheology to determine the optimum combinations to use for injection and then blended with inkjet-printed alginate microspheres. Drug release (FITC-Dextran) from Lutrol F127 alone reached completion in less than 24 h. Release from alginate spheres alone showed a burst release and reached 100% in 6 h. Interestingly, the incorporation of microspheres within Lutrol F127 allowed a more sustained release profile and a slower burst release. By varying the quantity of microspheres, concentration of alginate, or ionic cross-linking ratio, the release profile can be adjusted to suit the desired application. C

Engineering biomaterials by inkjet printing of hydrogels with functional particulates

“…Among all the printing methods, inkjet printing, a digital manufacturing technique renowned for its precision, versatility, and scalability, offers the potential to create customized drug delivery devices with unparalleled precision in drug loading and spatial distribution. It could not only customize and tailor drug dosages according to the specific needs of a patient [ 80 , 81 ] but also allow drug delivery systems with specific release profiles [ 82 , 83 ], such as delayed or sustained release, as shown in Fig. 6 A.…”

Photopolymerization of Bio-Based Polymers in a Biomedical Engineering Perspective

“…Inkjet is another bioprinting technology used for developing biomaterials, and recent reviews highlighted its application in tissue engineering. ,, The solid construct is formed by continuous deposition of droplets of dilute polymers solution, driven by thermal, piezoelectric, or acoustic forces. , Notable examples of the inkjet bioprinting application include the fabrication of alginate microspheres into a thermosensitive Pluronics hydrogel to locally deliver dextran to the inner ear, collagen/hydroxyapatite composites for bone scaffolds, or films of silk-based inks loaded with Au-nanoparticle, horseradish peroxidase, or antibiotic . Chitin nanofibers ink was developed by Zhong et al for airbrushing, replica molding, and microcontact printing …”

Multicomponent polysaccharide alginate-based bioinks

“…The influence of cross-linker concentration on the size of 3D printed microspheres was studied by O'Leary and co-workers, who prepared alginate microcapsules (0.5% wt/vol) for the release of the model drug dextran-fluorescein isothiocyanate (dextran-FITC) using an inkjet piezoelectric printing system. 58 The concentration of the CaCl 2 cross-linker bath was varied between 1.0 and 5.0% wt/vol. The microspheres obtained from the lowest cross-linker concentration (1.0% wt/vol) had a larger diameter (c.a.…”