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In this study, biomorphic poly(dl-lactic-co-glycolic acid)/nano-hydroxyapatite (PLGA/nHA) composite scaffolds were successfully prepared using cane as a template. The porous morphology, phase, compression characteristics and in vitro biocompatibility of the PLGA/nHA composite scaffolds and biomorphic PLGA scaffolds as control were investigated. The results showed that the biomorphic scaffolds preserved the original honeycomb-like architecture of cane and exhibited a bimodal porous structure. The average channel diameter and micropore size of the PLGA/nHA composite scaffolds were 164±52μm and 13±8μm, respectively, with a porosity of 89.3±1.4%. The incorporation of nHA into PLGA decreased the degree of crystallinity of PLGA, and significantly improved the compressive modulus of biomorphic scaffolds. The in vitro biocompatibility evaluation with MC3T3-E1 cells demonstrated that the biomorphic PLGA/nHA composite scaffolds could better support cell attachment, proliferation and differentiation than the biomorphic PLGA scaffolds. The localization depth of MC3T3-E1 cells within the channels of the biomorphic PLGA/nHA composite scaffolds could reach approximately 400μm. The results suggested that the biomorphic PLGA/nHA composite scaffolds were promising candidates for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Combination of different therapy modalities with multiple tumoricidal mechanisms has emerged as a promising anticancer strategy. Herein, we reported an aldehyde/catechol-functionalized hyaluronic acid (DAHA) and hydroxyethyl chitosan (HECS) decorated gold nanorod (GNR) platform for combined chemo-photothermal therapy of breast cancer. The DAHA was synthesized by conjugating dopamine onto oxidized hyaluronic acid. The nanoplatform was prepared by successively modifying GNR with DAHA via Au-catechol bonds, conjugating DOX onto DAHA moiety through Schiff base linkage, and coating HECS interlayer for charge-reversal and hyaluronic acid corona for tumor cell targeting. The resulting nanoplatform GNR-HADOXCH exhibited acid-triggered surface charge-reversal and pH/NIR dual-responsive drug release behaviors. The nanoplatform could be efficiently internalized into MCF-7 breast cancer cells and displayed greater cancer cell killing than individual modalities. Therefore, polysaccharide decoration could ensure the co-delivery of GNR and DOX into cancer cells, and the developed GNR-HADOXCH holds great potential for breast cancer treatment. Unlabelled Image • The versatile nanoplatform was prepared via a facile and effective self-assembly method. • The nanoplatform exhibited acid-triggered surface charge-reversal property. • The nanoplatform had pH/NIR dual-responsive drug release behavior. • Receptor recognition and charge-reversal dual-enhanced cellular internalization. • MCF-7 cells could be efficiently killed by combined chemo-photothermal therapy. [ABSTRACT FROM AUTHOR]

An ideal scaffold in bone tissue-engineering strategy should provide biomimetic extracellular matrix-like architecture and biological properties. Poly(γ-benzyl-L-glutamate) (PBLG) has been a popular model polypeptide for various potential biomedical applications due to its good biocompatibility and biodegradability. This study developed novel bimodal porous PBLG polypeptide scaffolds via a combination of biotemplating method and in situ ring-opening polymerization of γ-benzyl-L-gIutamate N-carboxyanhydride (BLG-NCA). The PBLG scaffolds were characterized by proton nuclear magnetic resonance spectroscopy, X-ray diffraction, differential scanning calorimetry, scanning electron microscope (SEM) and mechanical test. The results showed that the semi-crystalline PBLG scaffolds exhibited an anisotropic porous structure composed of honeycomb-like channels (100–200μm in diameter) and micropores (5–20μm), with a very high porosity of 97.4±1.6%. The compressive modulus and glass transition temperature were 402.8±20.6 kPa and 20.2°C, respectively. The in vitro biocompatibility evaluation with MC3T3-E1 cells using SEM, fluorescent staining and MTT assay revealed that the PBLG scaffolds had good biocompatibility and favored cell attachment, spread and proliferation. Therefore, the bimodal porous polypeptide scaffolds are promising for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Co-delivery of chemotherapeutic drug and small interfering RNA (siRNA) within a single nanovehicle has emerged as a promising combination therapy approach to treating cancers because of their synergistic effect. Nanocarrier delivery systems with low cytotoxicity and high efficiency are needed for such a purpose. In this study, a novel folate-conjugated PEGylated cationic triblock copolymer, poly(acrylhydrazine)- block -poly(3-dimethylaminopropyl methacrylamide)- block -poly(acrylhydrazine) (PAH- b -PDMAPMA- b -PAH), was synthesized and evaluated as a stimuli-sensitive vehicle for the targeted co-delivery of doxorubicin (DOX) and Bcl-2 siRNA into breast cancer MCF-7 cells. The synthetic process of the PEGylated triblock copolymer involved sequential reversible addition-fragmentation chain transfer polymerization, PEGylation and removal of tert -butoxy carbamate protecting groups. Folate-conjugated and/or -unconjugated poly(ethylene glycol) segments were grafted onto PAH- b -PDMAPMA- b -PAH via a reduction-sensitive disulfide linkage. The synthetic polymers were characterized by 1 H NMR and gel permeation chromatography. The PEGylated triblock copolymer could chemically conjugate DOX onto PAH blocks via pH-responsive hydrazone bonds and simultaneously complex negatively charged Bcl-2 siRNA with cationic PDMAPMA blocks through electrostatic interactions at N/P ratios ≥ 32:1 to form multifunctional nanomicelleplexes. The nanomicelleplexes exhibited spherical shape, possessed a positively charged surface with a zeta potential of + 22.5 mV and had a desirable and uniform particle size of 187 nm. In vitro release studies revealed that the nanomicelleplexes could release DOX and Bcl-2 siRNA in a reduction and pH dual-sensitive manner and the payload release was significantly enhanced in a reductive acidic environment mimicking the endosomes/lysosomes of cancer cells compared to under physiology conditions. Furthermore, the release of both DOX and siRNA was found to follow Higuchi kinetic model. Confocal laser scanning microscopy, flow cytometry and MTT analyses confirmed that, compared with folate-undecorated nanomicelleplexes, folate-decorated nanomicelleplexes could more effectively co-deliver DOX and Bcl-2 siRNA into MCF-7 cells and showed a stronger cell-killing effect. The pristine PEGylated triblock copolymer exhibited good cytocompatibility. Moreover, co-delivery of DOX and Bcl-2 siRNA achieved a significant synergistic antitumor efficacy. These findings suggested that the folate-decorated PEGylated cationic triblock copolymer might be a promising vehicle for targeted intracellular co-delivery of DOX and siRNA in MCF-7 cells, representing a potential clinical combination therapy for breast cancer treatment. [ABSTRACT FROM AUTHOR]

Though much progress in utilizing tissue engineering technology to investigate tumor development in vitro has been made, the effective management of human melanoma is still a challenge in clinic due to lack of suitable 3D culture systems. In this study, we prepared a poly(γ-benzyl- l -glutamate)/poly(lactic acid) (PBLG/PLA) nanofiber membrane by electrospinning and demonstrated its suitability as a matrix for 3D culture of melanoma cells in vitro . The electrospun PBLG/PLA nanofiber membrane displayed a smooth and uniform fibrous morphology and had a desirable water contact angle of 79.3 ± 0.6°. The average diameter of PBLG/PLA nanofibers was 320.3 ± 95.1 nm that was less than that (516.2 ± 163.3 nm) of pure PLA nanofibers. The addition of PBLG into PLA decreased the cold crystallization peak of PLA fibers from 93 to 75 °C. The in vitro biocompatibility of PBLG/PLA nanofiber membrane was evaluated with B16F10 cells using PLA nanofiber membrane as control. It was found that, compared to PLA nanofiber membrane, PBLG/PLA nanofiber membrane could better support cell viability and proliferation, as indicated by MTT assay and live-dead staining. SEM results revealed that PBLG/PLA rather than PLA nanofiber membrane promoted the generation of tumoroid-like structures. These findings clearly demonstrated that the electrospun PBLG/PLA nanofiber membrane could mimick the extracellular matrix of melanoma microenvironment and be a promising platform for 3D cell culture. [ABSTRACT FROM AUTHOR]

In this study, novel poly(γ-benzyl l -glutamate)/poly(lactic- co -glycolic acid)/bioglass (PBLG/PLGA/BG) composite scaffolds with different weight ratios were fabricated using a negative NaCl-templating method. The morphology, compression modulus and degradation kinetics of the scaffolds were characterized. The results showed that the PBLG/PLGA/BG composite scaffolds with a weight ratio of 5:5:1, namely PBLG5PLGA5BG composite scaffolds, displayed a pore size range of 50–500 μm, high compressive modulus (566.6 ± 8.8 kPa), suitable glass transition temperature (46.8 ± 0.2 °C) and low degradation rate (> 8 weeks). The in vitro biocompatibility of the scaffolds was evaluated with MC3T3-E1 cells by live-dead staining, MTT and ALP activity assays. The obtained results indicated that the PBLG5PLGA5BG composite scaffolds were more conducive to the adhesion, proliferation and osteoblastic differentiation of MC3T3-E1 cells than PBLG and PBLG/PLGA composite scaffolds. The in vivo biocompatibility of the scaffolds was evaluated in both SD rat subcutaneous model and rabbit tibia defect model. The results of H&E, Masson's trichrome and CD34 staining assays demonstrated that the PBLG5PLGA5BG composite scaffolds allowed the ingrowth of tissue and microvessels more effectively than PBLG/PLGA composite scaffolds. The results of digital radiography confirmed that the PBLG5PLGA5BG composite scaffolds significantly improved in vivo osteogenesis. Collectively, the PBLG5PLGA5BG composite scaffolds could be a promising candidate for tissue engineering applications. [ABSTRACT FROM AUTHOR]

A comb-like amphiphilic copolymer methoxypolyethylene glycol- graft -poly( l -lysine)- block -poly( l -phenylalanine) (mPEG- g -PLL- b -Phe) was successfully synthesized. To synthesize mPEG- g -PLL- b -Phe, diblock copolymer PLL- b -Phe was first synthesized by successive ring-opening polymerization of α-amino acid N-carboxyanhydrides followed by the removal of benzyloxycarbonyl protecting groups, and then mPEG was grafted onto PLL- b -Phe by reductive amination via Schiff's base formation. The chemical structures of the copolymers were identified by 1 H NMR. mPEG- g -PLL- b -Phe copolymer had a critical micelle concentration of 6.0 mg/L and could self-assemble in an aqueous solution into multicompartment nanomicelles with a mean diameter of approximately 78 nm. The nanomicelles could encapsulate doxorubicin (DOX) through hydrophobic and π–π stacking interactions between DOX molecules and Phe blocks and simultaneously complex P-gp siRNA with cationic PLL blocks via electrostatic interactions. The DOX/P-gp siRNA-loaded nanomicelles showed spherical morphology, possessed narrow particle size distribution and had a mean particle size of 120 nm. The DOX/P-gp siRNA-loaded nanomicelles exhibited pH-responsive release behaviors and displayed accelerated release under acidic conditions. The DOX/P-gp siRNA-loaded nanomicelles were efficiently internalized into MCF-7 cells, and DOX released could successfully reach nuclei. In vitro cytotoxicity assay demonstrated that the DOX/P-gp siRNA-loaded nanomicelles showed a much higher cytotoxicity in MCF-7 cells than DOX-loaded nanomicelles due to their synergistic killing effect and that the blank nanomicelles had good biocompatibility. Thus, the novel comb-like mPEG- g -PLL- b -Phe nanomicelles could be a promising vehicle for co-delivery of chemotherapeutic drug and genetic material. [ABSTRACT FROM AUTHOR]