•A versatile strategy to prepare propargyl focal point novel siloxane-poly (amido amine) typed dendrons was described.•Different generations of porphyrin-cored dendrimers were successfully obtained via click chemistry.•The synthesized porphyrin-cored dendrimers gave strong and remarkable pH-dependent behaviour in fluorescence emission.Different generations of porphyrin-cored dendrimers consisting of novel siloxane- poly(amido amine) dendron-like arms have been synthesized via copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of azide-modified 5,10,15,20-tetrakis(4-hydroxyphenyl)-porphyrin with different generations of propargyl focal point novel siloxane-poly(amido amine) typed dendron (Si-PAMAM). The used different generations of Si-PAMAM were obtained by the “arm-first” strategy based on the Michael addition reaction and Amidation reaction, orderly. The structure of porphyrin dendrimers is established by 1H NMR, 13C NMR, MALDI-TOF-MS and FT-IR analysis. PP-Si-PAMAM-Dm (m = 1, 2, and 3), not only gave strong fluorescence emission and the intensity increased significantly as the generation growing, but also showed a remarkable pH-responsive in fluorescence emission. These interesting properties indicate that synthesized porphyrin dendrimers may be able to act as pH-responsive probes suitable for biomedical imaging, diagnosis and treatment.Download high-res image (96KB)Download full-size image

•A shear-thinning supramolecular hydrogel was easily formed by star-shaped copolymer and α-cyclodextrin based on the host–guest interaction.•The gelation forces included strong hydrogen bonding, hydrophobic interaction and π–π stacking.•The release-kinetics of the DOX-loaded supramolecular hydrogel bear a triphasic drug-release profile and the release of this system lasted more than 3 weeks.•Upon irradiation with light (650 nm), this supramolecular hydrogel showed a high singlet oxygen generation for photodynamic therapy.An amphiphilic porphyrin-cored, star-shaped poly (ε-caprolactone)-b-poly (ethylene glycol) (SPPCL-b-PEG) copolymer was synthesized and used as a building block for constructing supramolecular hydrogels. With the aid of α-cyclodextrin (α-CD), thixotropic and reversible supramolecular hydrogel could be formed by copolymers based on the host–guest inclusion complexation (IC). Due to the biodegradable and biocompatible properties, this IC-based supramolecular hydrogel was used as carrier for doxorubicin (DOX) delivery systems. The release results presented a triphasic drug-release profile and the release of this system lasted more than 3 weeks. Also, upon irradiation with light (650 nm), cytotoxic singlet oxygen (1O2) could be generated by porphyrin core and easily released from hydrogel matrix. Considering that both sustained-release drug delivery of hydrogels and porphyrin for photodynamic therapy (PDT) were achieved in a combined compound, this shear-thinning supramolecular hydrogel with porphyrin was elaborately designed as a promising replacement therapy to medium or advanced cancer for surgery.

Thermosensitive, star-shaped porphyrin-cored poly(L-lactide)-block-poly(N-isopropylacrylamide) (SPPLA–PNIPAM) was synthesized via ring-opening polymerization (ROP) and reversible addition–fragmentation chain transfer polymerization (RAFT). The composition and properties of copolymer were discussed based on the results of NMR, IR and GPC. With PNIPAM block length decreasing, the morphology of SPPLA–PNIPAM copolymer in aqueous solution transformed hierarchically from spherical micelles through wormlike micelles to vesicles, and the lower critical solution temperatures (LCST) of the copolymer solutions were determined to be 37.9°, 37.2°, 35.9°, respectively. The in vitro study indicated that SPPLA–PNIPAM showed no significant dark cytotoxicity at concentrations up to 128 μg/mL, while showed apparent phototoxicity toward BEL-7402 cancer cells. Considering a high singlet oxygen quantum yield and suitable nominal physiologic LCST, it is expected that the SPPLA–PNIPAM copolymer is a promising stimulus-responsive candidate which has a potential application in photodynamic therapy (PDT).

Star-shaped poly(L-lactide)-b-poly(ethylene glycol) (SPPLA-b-PEG) block copolymers with porphyrin cores were successfully synthesized from the ring-opening polymerization (ROP) of L-lactide initiated with a porphyrin core, followed by a coupling reaction with a hydrophilic PEG polymer shell. The structure of this novel copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy (NMR), Gel Permeation Chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The SPPLA-b-PEG copolymer exhibits efficient singlet oxygen generation and displays high fluorescence quantum yields. Notably, the self-assembly of the as-prepared porphyrin-cored star-shaped copolymer into micelle-like structures provides the great potential of using this well-defined porphyrin core material for drug delivery systems. Particularly, doxorubicin-loaded SPPLA-b-PEG nanospheres exhibit pH-induced drug release properties.

In this study, star-shaped porphyrin-cored poly(ε-caprolactone)-b-poly(gluconamidoethyl methacrylate) block copolymers (SPPCL-PGAMA) were successfully obtained. The synthetic route was via the ring-opening polymerization (ROP) of ε-caprolactone using a tetra-hydroxyethyl terminated porphyrin as a core initiator followed by the atom transfer radical polymerization (ATRP) of unprotected gluconamidoethyl methacrylate (GAMA) in 1-methyl-2-pyrrolidinone (NMP) solution at room temperature. The structure of the copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy (NMR), Gel Permeation Chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Notably, the as-prepared SPPCL-b-PGAMA that formed different structures being used for drug delivery systems has been researched. Moreover, this copolymer can release singlet oxygen under light irradiation and the singlet oxygen could be used for photodynamic therapy. In particular, UV-vis analysis showed that SPPCL-b-PGAMA has a very specific recognition with Concanavalin A (Con A) which provides porphyrin-cored SPPCL-b-PGAMA block copolymers for targeted drug delivery.

Porphyrin-cored poly(l-lactide) (SPPLA) was successfully synthesized from ring-opening polymerization (ROP) of l-lactide initiated with porphyrin core. Then, SPPLA was coupled with benzylsulfanylthiocarbonylsufanylpropionic acid (BSPA), and a macro-reversible addition-fragmentation chain transfer (macroRAFT) polymerization agent SPPLA-BSPA was obtained. Finally, star-shaped porphyrin-cored poly(l-lactide)-b-poly(gluconamidoethyl methacrylate) (SPPLA-b-PGAMA) block copolymers were synthesized via RAFT of unprotected gluconamidoethyl methacrylate (GAMA) in 1-methyl-2-pyrrolidinone (NMP) solution at 70 °C. The structure of this block copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Under the irradiation, such SPPLA-b-PGAMA copolymer exhibits efficient singlet oxygen generation and indicates high fluorescence quantum yields. Notably, with UV–vis and dynamic light scattering (DLS) analysis, SPPLA-b-PGAMA showed a very specific recognition with concanavalin A (ConA). Particularly, MTT shows that the cytotoxicity of SPPLA-b-PGAMA against COS-7 cells was very low and, when given a longer irradiation time, more BEL-7402 cancer cells died, which will be investigated in this study.