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Supplementary Information for

Clickable, Acid Labile Immunosuppressive Prodrugs for In Vivo Targeting

Hua Wang1,2, Miguel C. Sobral1,2, Tracy Snyder2, Yevgeny Brudno1,2, Vijay Gorantla3*, David J.

Mooney1,2*

1Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University,

Cambridge, Massachusetts 02138, USA. 2Wyss Institute for Biologically Inspired Engineering,

Cambridge, Massachusetts 02138, USA. 3Surgery, Ophthalmology and Bioengineering, Wake

Forest School of Medicine, Winston-Salem, NC 27101, USA.

*email: mooneyd@seas.harvard.edu

*email: vgorantl@wakehealth.edu

Keywords: Keywords: immunosuppression, organ/reconstructive transplantation, prodrug, in

vivo targeting, Click chemistry

Electronic Supplementary Material (ESI) for Biomaterials Science.This journal is © The Royal Society of Chemistry 2019

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Figure S1. Synthesis and characterizations of rapamycin-mal. (a) Synthetic route of rapamycin-mal. (b) HPLC profile of rapamycin-mal, detected at 254 nm. (c) Mass spectra of rapamycin-mal in negative and positive mode, respectively.

O

N

O O

O

N

O

O

O

O

O

OH

OH

OH

HH

HN

O N

O

O

O

N

O O

O

O

O

O

O

O

O

OH

OH

OH

HH

HN

ON

O

OH2N

AcOH, MeOH, 45oC

Rapamycin

BMPH

Rapamycin-malm/z: 1078.61 (100.0%)

[M-H]- [M+H]+

a

b

c

Negative mode positive mode

3

Figure S2. Synthesis and characterizations of DBCO-PEG1k-SH. (a) Synthetic route of DBCO-PEG1k-SH. (b) HPLC profile of the mixture of DBCO-NHS and NH2-PEG1k-SH after 24-h reaction. (c) Mass spectra of NH2-PEG1k-SH and DBCO-PEG1k-SH, respectively. Peak shift confirmed the successful conjugation.

m/z:121.06+44.02*nm/z:408.16+44.02*n’

554.4 + (408.16 - 121.06)/2 = 698.0576.4 + (408.16 - 121.06)/2 = 720.0

NH2-PEG1k-SHDBCO-PEG1k-SH

H2NO O SHN

OO

ON

O

O

DBCO-NHS

NH2-PEG1k-SH

N

O

O

NH

O O SH

DBCO-PEG1k-SH

a

b

c

4

Figure S3. FTIR spectrum of alginate-N3. The peak at 2106 cm-1 confirms the existence of azido groups.

1.0

0.9

0.8

0.7

0.6

0.53500 3000 2500 2000 1500 1000

Wavelength (cm-1)

N3

5

Figure S4. Synthesis and characterizations of tacrolimus-mal. (a) Synthetic route of tacrolimus-mal. (b) Mass spectrum of tacrolimus-mal in positive mode. (c) 1H NMR spectrum of tacrolimus-mal in CDCl3.

ON

O O

O

O

O

OO

OHO

OHH

H

O

N

O O

N

O

OO

O

O

HO

OHH

H

HNO

N

O

O

HN

O

O

OH2N

AcOH, 45oC

Tacrolimus Tacrolimus-mal

OH

OH

a

b [M+H]+

[M+H]+ calculated: 969.5Observed: 969.4

c

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Figure S5. Synthesis and characterizations of MPA-4-nitrophyenylcarbonate. (a) Synthetic route of MPA-4-nitrophyenylcarbonate. (b) HPLC profile of MPA-4-nitrophyenylcarbonate. (c) Mass spectrum of MPA-4-nitrophyenylcarbonate in positive mode.

O

O

NO2

Cl

TEA, DCM

OOH

O

O

O

OH

OOH

O

O

O

OO

O

NO2MPA

MPA-4-nitrophenylcarbonate

a

b

c

[M+H]+

[2M+Na]+

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Figure S6. Loading kinetics of DBCO-hz-rapa into alginate-N3 and unmodified alginate gels, respectively. Data are presented as mean ± SD (n=4).

Figure S7. Loading kinetics of rapamycin into alginate-N3 gels via diffusion. Rapamycin was first dissolved in dimethyl sulfoxide before being added into the medium. Data are presented as mean ± SD (n=3).

0

25

50

75

100

0 3 6 9

% L

oadi

ng o

f D

BCO

-hz-

rapa

Loading Time (h)

Alginate-N3Control alginate

0

20

40

60

80

100

0 6 12 18 24

% D

iffus

ed R

apam

ycin

Time (h)

8

Figure S8. Release profile of DBCO-hz-rapa from unmodified alginate gels at pH 7.4 (n=4). Gels with diffusively loaded DBCO-hz-rapa were placed in fresh medium and monitored for drug release. Data are presented as mean ± SD.

Figure S9. Loading kinetics of DBCO-hz-tacro into alginate-N3 and unmodified alginate gels, respectively. Data are presented as mean ± SD (n=4).

0

25

50

75

100

0 20 40 60 80 100

% D

BCO

-hz-

rapa

rele

ase

Time (h)

0

20

4060

80

100

0 6 12 18 24

% L

oadi

ng o

f D

BCO

-hz-

tacr

o

Loading Time (h)

Alginate-N3Control Alginate

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Figure S10. Loading kinetics of DBCO-MPA into alginate-N3 and unmodified alginate gels, respectively. Data are presented as mean ± SD (n=4).

0

20

40

60

80

100

0 6 12 18 24

% L

oadi

ng o

f D

BCO

-MPA

Loading time (h)

Alginate-N3Control alginate

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Figure S11. Pharmacokinetics of DBCO-hz-rapa. DBCO-hz-rapa (50 mg/kg) was tail vein injected to Balb/c mice. Blood (10 µL) was collected from orbital sinus at selected time points (1, 3, 9, 24, and 48 h), lysed, and diluted with water/methanol (1/2, v/v, 90 µL) prior to HPLC analyses.

0

10

20

30

40

0 12 24 36 48

DBC

O-h

z-ra

pa in

Blo

od (µ

g/m

L)

Time Post Injection (h)

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Figure S12. Pharmacokinetics of DBCO-hz-tacro. DBCO-hz-tacro (50 mg/kg) was tail vein injected to Balb/c mice. Blood (10 µL) was collected from orbital sinus at selected time points (0.2, 2, 6, 24, and 48 h), lysed, and diluted with water/methanol (1/2, v/v, 90 µL) prior to HPLC analyses.

0

20

40

60

0 12 24 36 48

DBC

O-h

z-ta

cro

in B

lood

(µ

g/m

L)

Time Post Injection (h)

12

Figure S13. Pharmacokinetics of DBCO-MPA. DBCO-MPA (50 mg/kg) was tail vein injected to Balb/c mice. Blood (10 µL) was collected from orbital sinus at selected time points (0.5, 2, 6, 12, 24, and 48 h), lysed, and diluted with water/methanol (1/2, v/v, 90 µL) prior to HPLC analyses.

0

20

40

60

0 12 24 36 48

DBC

O-M

PA in

Blo

od

(µg/

mL)

Time Post Injection (h)

13

Figure S14. In vivo reloading of DBCO-hz-rapa to alginate-N3 gels. (a) Schematic illustration of in vivo reloading study. Alginate-N3 or control alginate gels (100 µL) were subcutaneously injected into the right flank of Balb/c mice. After 1 h, DBCO-hz-rapa (150 mg/kg) was i.v. injected via tail vein. At 48 h, gels were dissociated in the presence of EDTA and treated with formic acid prior to HPLC analyses. (b) Amount of rapamycin recovered from alginate-N3 or control alginate gels at 48 h (n=3). (c) Amount of loaded rapamycin presented as the percentage of injected dose (n=3). Data were presented as mean ± SD and analyzed by two-tailed t-test (0.01 < *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001).

b

a

cAl

ginate

-N 3Co

ntrol

algina

te0

4

8

12

Load

ed

Rap

amyc

in (µ

g) *

hours481

Alg-N3 orcontrol Alg Gel, subQ

Quantification of drugs in gels

0

Prodrugi.v.

0

0.4

0.8

1.2

% In

ject

ed D

ose *

Algin

ate-N

3Co

ntrol

algina

te