Supplemental figure 1: Histological correlation. (a) Low-power view and (b) high power view (inset) of swine liver post MC transplantation stained

Transcription

1 Supplemental figure 1: Histological correlation. (a) Low-power view and (b) high power view (inset) of swine liver post MC transplantation stained with Prussian Blue (PB) for iron. PB-positive MCs are lodged in sinuses. (c) Ex vivo MR image of corresponding slice in (a). (d) 3D reconstruction of MC distribution (green) obtained with in vivo MRI (for full 3D animation see Supplementary movie 2). Blue = gall bladder.

2 Supplementary Information Magnetic Resonance-Guided, Real-Time Targeted Delivery and Imaging of Magnetocapsules Immunoprotecting Pancreatic Islet Cells Brad P. Barnett 1,2, Aravind Arepally 1, Parag V. Karmarkar 1, Di Qian 1, Wesley D. Gilson 1, Piotr Walczak 1,2, Valerie Howland 1, Leo Lawler 1, Cal Lauzon 1,2, Matthias Stuber 1, Dara L. Kraitchman 1, Jeff W.M. Bulte 1,2 1 Russell H. Morgan Department of Radiology and Radiological Science and 2 Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States. Methods Permeability of microcapsules For lectin permeability measurements, capsules were incubated with either 15 L (1 mg/ml) of FITC-Triticum vulgare (WGA, MW=36 kda), FITC-Maackia amurensis I (MAL-I, MW=75 kda), FITC-Ricinus communis (RCA-I, MW=120 kda), or FITC-Sambuca nigra (SNA, MW=150 kda). All lectins were obtained from EY Lab Inc., except FITC-Maackia amurensis I (Vector laboratories). Capsules were incubated for 48h at 4 C on a mechanical rocker, after which they were examined microscopically (Olympus X51 and IX71 epifluorescence microscopes equipped with an Olympus DP-70 digital acquisition system) following embedding with Vectashield mounting medium (Vector). Macroscopic images of microcapsules in 6-well plates were obtained with a D100 6MP Digital SLR Camera (Nikon).

3 Glucose-Stimulated Insulin Secretion A static incubation assay was used to assess the insulin secretion response of encapsulated human islets. A step-wise increase in glucose concentration from 3.3 to 16.7 mm D-glucose in RPMI 1640 medium (purchased as glucose-free) was used to assess the glucose responsiveness of encapsulated cells. The glucose responsiveness index was calculated as (1-(3.3mM (cpeptide)/16.7mm (c-peptide)). Following 24 hr of culture post encapsulation, islets were preincubated at 37 C for 45 min in glucose and serum-free RPMI-1640 with 0.5% BSA and 3.3 mmol/l glucose added. Fifty encapsulated islets were placed in a culture insert (membrane pore diameter 12 m; Millicell PFC) in six well plates. 5 ml of fresh serum-free RPMI-1640 with 0.5% BSA and 3.3 mmol/l glucose was added to each well. After an additional 45-min incubation period at 37 C, the media was removed and replaced with RPMI-1640 with 0.5% BSA and 16.7 mmol/l glucose, again with 5 ml of media added per well. Encapsulated islets were incubated for an additional 45 min in this high-glucose medium. Aliquots of the medium at low (3.3 mmol/l) and high (16.7 mmol/l) glucose concentrations were stored at -80 C. The C-peptide content of the samples was determined with an enzyme-linked immunosorbent assay (ultrasensitive human c- peptide ELISA, Alpco Diagnostics); results (in ng/ml) were expressed as the mean of three independent experiments. MRI of phantoms Phantom imaging was performed on a 3T Philips Achieva MR scanner with a 6-element cardiac phased-array receiver coil. For three-dimensional T2-*weighted gradient echo imaging, which provides hypointense contrast, the imaging parameters were: repetition time (TR)=7.0 ms; echo time (TE)=2.3 ms; flip angle (FA)=15 ; field of view (FOV)=22 cm; matrix=512x512; and slice thickness (ST)=1 mm. For fast spin echo 3D IRON imaging, which provides bright contrast, the imaging parameters were the same except for TR=1300 ms; TE=12.0 ms; IRON pulse

4 bandwidth (BW IRON )=170Hz; and turbo factor=18. MRI of mice MRI was performed at 9.4 T (Bruker horizontal scanner) using a custom-built animal holder and a whole-body volume transmitting/receiving coil. T2-weighted spin echo (SE) and T2*- weighted gradient echo sequences (GRE) were used. The SE parameters were TR=1500 ms, TE=15 ms, FOV=3x3 cm, matrix=196x196, ST=0.8 mm, and number of signal averages=4. GRE parameters were the same, except for TR=500 ms, TE=6 ms, matrix=296x296, and FA=30. MRI of swine Animals were sedated with 1 ml/50 lbs of telazol/ketamine/xylazine (100/10/100 mg/ml IM) and induced with sodium thiopental (25 mg/ml IV to effect). Induction was followed by endotracheal intubation and mechanical ventilation with oxygen and 1-2% isoflurane anesthesia. In vivo imaging was performed on a 1.5 T MR scanner (CV/i, GE Medical Systems) using a 4 channel phased-array coil and a real-time, steady-state free precession sequence (TR=3.4 ms, TE=1.2 ms, FA=45º, receiver BW=125 khz, ST=10 mm, FOV=30x30 cm, and matrix=128x128). In combination with an interactive scan plane acquisition (i-drive, GE Medical Systems), the needle was advanced into the IVC. Prior to and following the puncture procedure, a contrastenhanced MR angiogram (MRA) of the mesenteric venous system was obtained by IV injection of 30 ml of 0.1 mmol/kg gadopentate dimeglumine (Magnevist, Berlex Laboratories Inc.) at 2 ml/sec. The imaging parameters were: TR=4.8 ms, TE=1.4 ms, flip angle=25º, BW=31.2 khz, FOV=30x30 cm 2, and matrix=256x256. MRI of explanted liver

5 MRI was performed at 3T on a Philips Achieva MR scanner using a 6-element cardiac phasedarray coil and a three-dimensional GRE sequence. The imaging parameters were: TR=12.8 ms, TE=6.3 ms, FA=15, FOV=28 cm, matrix=512x512, and slice thickness=1 mm. MR data processing was performed using Amira 3.1 software (Mercury Computer Systems). For visualization of MC liver distribution, a signal intensity threshold was applied to dissect the range of signal intensities that corresponded to MCs. For the obtained data, surface rendering of MCrelated pixels was performed, color-coded (green), and superimposed with surface rendering of the complete data set (red). Results Table 1: Permeability ( ) and nonpermeability (X) of non-labeled capsules and MCs for lectins with various molecular weights. Following incorporation of Feridex, the permeability is unaltered with free diffusion of lectins 75 kda, but not for lectins 120 kda. Capsules Feridex Capsules + Feridex 36 kda 75 kda 120 kda X X 150 kda X X