SILVER NANOPARTICLES-LOADED CALCIUM ALGINATE BEADS EMBEDDED IN GELATIN SCAFFOLDS AND THEIR RELEASE CHARACTERISTICS Presented by: Porntipa Pankongadisak Materials Science, School of Science Mae Fah Luang University

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3 SILVER NANOPARTICLES (AgNPs)

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ELECTROHYDRODYNAMIC SPRAYING (EHDA) 5 Negative electrode Ground electrode

ALGINATE 6

SCAFFOLDS 7 Scaffolds

GELATIN 8

PROBLEMS 9 9

OBJECTIVES 1)To prepare the AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds 2)To characterize the AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds (morphology, thermal properties, mechanical properties, water swelling and weight loss behavior and, release characteristic of Ag + ions) 10

Part 1: Preparation of pure calcium alginate beads and AgNPs-loaded calcium alginate beads 4%w/w AgNO 3 solution was initially prepared and mixed with 1.5% w/v of Na alginate. AgNO 3 /alginate solution was irradiated by UV light for 1 h. Alginate beads incorporated with AgNPs were fabricated by EHDA. The wet and dry beads were observed the morphology and size by Optical Microscope (OM) and Scanning Electron Microscope (SEM), respectively. 12 Negative electrode Ground electrode

Part 2: Preparation of AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds 5%w/v gelatin solution was initially prepared and added genipin as crosslinking agent. The solution was mixed to obtain homogeneous solution by magnetic stirrer for 1 h. The dry beads were added into the GP-crosslinked gelatin solution and then poured it into the mold to form gel. The gel was left in the room temp. for crosslinking over night and then it was freezed at -40 °C. The frozen gel was lyophilized by freeze-dryer for over night to obtain the porous scaffolds. 13

Part 3: Characterization of AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds Morphology Scanning Electron Microscope (SEM) Thermal properties Thermogravimetric Analyzer (TGA) Mechanical properties Universal Testing Machine (UTM) Water swelling and Weight loss properties Release characteristic Total Immersion Method in PBS at 37 °C 14

Morphology Table 1: Optical micrographs (OM), scanning electron micrographs (SEM) and diameters of the pure calcium-alginate beads and AgNPs-loaded calcium- alginate beads 16 Sample Observed by OMDiameter (µm)SEMDiameter(µm) Control ± ± AgNPs ± ± Adding Ag into the beads affected the size of beads to decrease.

Morphology Table 2: Selected SEM image of the pure calcium alginate beads embedded in gelatin scaffolds and AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds 17 SampleSEMPore size (µm) Pure beads embedded in gelatin scaffolds ± AgNPs-loaded beads embedded in gelatin scaffolds ± 85.71

Thermal properties 18 Figure 2: Thermogravimetric analysis (TGA) of the pure calcium alginate beads embedded in gelatin scaffolds and AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds

Mechanical stability 19 SampleCompressive Modulus (kPa) Pure beads embedded in gelatin scaffolds 3.60 ± 0.85 AgNPs-loaded beads embedded in gelatin scaffolds 2.78 ± 1.03 Table 3: Compressive modulus of the pure calcium alginate beads embedded in gelatin scaffolds and AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds

Water swelling 20 Figure 3: Water swelling of the pure calcium alginate beads embedded in gelatin scaffolds and AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds.

Weight loss 21 Figure 4: Weight loss of the pure calcium alginate beads embedded in gelatin scaffolds and silver nanoparticles-loaded calcium alginate beads embedded in gelatin scaffolds.

Release characteristic 22 Figure 5: Cumulative release profiles of Ag + ions from AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds in phosphate buffer solution at 37 °C.

CONCLUSIONS 23 The AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds were successfully fabricated. The incorporation of AgNPs-loaded into the calcium alginate beads decreased the size of beads. The morphology of the AgNPs-loaded calcium alginate beads embedded in gelatin scaffolds showed the interconnected pore structure. The incorporation of AgNPs into the calcium alginate beads embedded in gelatin scaffolds decreased the strength of materials.

CONCLUSIONS 24 The water swelling and weight loss behavior of the scaffolds increased with an increase in the submersion time. The release of Ag ions from the scaffolds gradually increased with increase in submersion time and then reached a plateau value at day 3, and continually increased to reach 80% release at day 7.

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ACKNOWLEDGEMENTS “The authors would like to acknowledge the financial support from the Research, Development and Engineering (RD&E) fund through The National Nanotechnology Center (NANOTEC), The National Science and Technology Development Agency (NSTDA), Thailand (P ) to Mae Fah Luang University (MFU) and Thailand Graduate Institute of Science and Technology (TGIST) (TG M)” 26

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