Synthesis and Self-assembly Properties of Intracellular Redox Bioresponsive Block Copolymers with Hepatoma-targeting Groups†

doi:10.7503/cjcu20170714

Abstract

Abstract:

The amphiphilic block copolymers PMAIgGP-b-PPDSMA(PMgPP) with a hydrophilic block containing galactose side groups and a hydrophobic segment containing pyridine ring disulfide pendant groups were prepared by two-step reversible addition-fragmentation chain transfer(RAFT) polymerization and acetal deprotection reaction. Their well-defined chemical structures were confirmed by proton nuclear magnetic resonance(¹H NMR) and gel permeation chromatography(GPC). Core-crosslinked PMgPP nanoparticles(PMgPP-CC NPs) were prepared by nano-precipitation technology and thiol oxidation self-crosslinking reaction. Dynamic light scattering(DLS) and transmission electron microscopy(TEM) were used to determine the size of PMgPP-CC NPs(<30 nm) and the particle size distribution indexes were narrow. Under the reduction environment of GSH, the particle sizes of PMgPP-CC NPs were increasing with incubation time, indicating the disassembly of PMgPP-CC NPs. PMgPP-CC/DOX NPs were prepared by DOX as the model drug, and drug loading content up to 12.5% and entrapment efficiency of 83.3%. The particle sizes were similar to that of the corresponding blank CC NPs, and the particle size distribution was uniform. Within 46 h in vitro, 4.47% of DOX was released from the PMgPP-CC/DOX NPs in normal physiological conditions, whereas 50.6% was released in the presence of 10 mmol/L GSH condition analogous to the reductive microenvironment in cytoplasm. The cell uptake tests further confirmed that PMgPP-CC/DOX NPs could be efficiently released in the HepG-2 cells. 3-(4,5-dimethyethiazol-2-yl)-2,5-diphemptetrazolium bromide(MTT) assays show that PMgPP-CC/DOX NPs has good proliferation inhibitory activity against HepG-2 cells. Therefore, multifunctional PMgPP-CC NPs have a good prospect in the field of precise hepatoma-targeting drug delivery.

Key words: Galactose, Redox-sensitive, Core-crosslinked block copolymer, Reversible addition-fragmentation chaintransfer(RAFT) polymerization, Drug delivery

CLC Number:

O631
TQ463

TrendMD:

ZHAO Junqiang, YAN Caixia, CHEN Ze, YANG Ning, FENG Xia, ZHAO Yiping, CHEN Li. Synthesis and Self-assembly Properties of Intracellular Redox Bioresponsive Block Copolymers with Hepatoma-targeting Groups^†[J]. Chem. J. Chinese Universities, 2018, 39(7): 1592.

Figures/Tables 14

Scheme 1 Schematic illustration of PMgPP-CC/DOX NPs with intracellular redox-responsive properties for GAL-mediated targeted delivery of DOX

Scheme 2 ynthesis routes of PMgPP

Fig.1 1H NMR spectra of MAIpGP(A) and PDSMA(B) monomers

Fig.2 1H NMR spectra of PMAIpGP-CTA(A), PMpPP(I)(B) and PMgPP(Ⅱ)(C) and GPC elution chromatograms of PMAIpGP-CTA and PMpPP(D)

Table 1 Chemical structure and compositions of PMpPP(Ⅰ) and PMgPP(Ⅱ)

Sample	Composition(/unit)(¹H NMR)		M_n (¹H NMR)	M_w/M_n(GPC)	M_n(PMAIpGP)/M_n(PPDSMA) (¹H NMR)
Sample	MAIpGP	PDSMA	M_n (¹H NMR)	M_w/M_n(GPC)	M_n(PMAIpGP)/M_n(PPDSMA) (¹H NMR)
PMpPP(Ⅰ)	25.0	29.0	16013	1.09	0.63
PMpPP(Ⅱ)	25.0	39.0	18566	1.32	0.50

Fig.3 DLS measurements of 1.0 mg/mL PMgPP(Ⅱ)-NC NPs(a), 1.0 mg/mL PMgPP(Ⅱ)-CC NPs(b), 1.0 μg/mL PMgPP(Ⅱ)-NC NPs(c) and 1.0 μg/mL PMgPP(Ⅱ)-CC NPs(d)

Table 2 Characteristics of blank PMgPP-NC NPs and PMgPP-CC NPs

Sample	NC NPs		CC NPs
Sample	Size/nm	PDI	Size/nm	PDI
PMgPPI	23.9±0.8	0.14	22.7±1.5	0.16
PMgPPII	26.0±1.6	0.15	23.7±0.2	0.18

Fig.4 Reduction-induced size changes of PMgPP(Ⅱ)-CC NPs^Concentration of GSH/(mmol·L-1) and time/h: a. 0, 0; b. 10, 5; c. 10, 10; d. 10, 24.

Table 3 Characteristics of PMgPP-NC/DOX NPs and PMgPP-CC/DOX NPs*

Sample	NC/DOX NPs				CC/DOX NPs
Sample	Size/nm	PDI	DLC(%)	DLE(%)	Size/nm	PDI	DLC(%)	DLE(%)
PMgPP(Ⅰ)	21.5 ± 4.8	0.16	11.9	79.3	20.1 ± 4.8	0.19	11.7	78.0
PMgPP(Ⅱ)	25.0 ± 3.2	0.19	12.0	80.0	24.8 ± 3.9	0.18	12.5	83.3

Fig.5 TEM images of PMgPP(Ⅱ)-NC/DOX NPs(A) and PMgPP(Ⅱ)-CC/DOX NPs(B)

Fig.6 GSH-triggered DOX release profiles from PMgPP(Ⅱ)-NC/DOX NPs(a, b) and PMgPP(Ⅱ)-CC/DOX NPs(c, d)^Concentration of GSH(mmol·L-1): a, c. 0; b, d. 10.

Fig.7 CLSM images of HepG-2 cells after incubated with PMgPP(Ⅱ)-NC/DOX NPs(A—C), PMgPP(Ⅱ)-CC/DOX NPs(D—F) and free DOX(G—I) at equivalent DOX concentration of 10.0 μg/mL for 8 h^Images from left to right show DOX fluorescence in cells(red) and cell nuclei stained by DAPI(blue) and overlays of two images.

Fig.8 In vitro cytotoxicity of blank PMgPP(Ⅱ)-NC NPs and PMgPP(Ⅱ)-CC NPs towards HepG-2 cells

Fig.9 Cell growth inhibition activity of free DOX, PMgPP(Ⅱ)-NC/DOX NPs and PMgPP(Ⅱ)-CC/DOX NPs as a function of DOX dosages towards HepG-2 cells

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