Manipulation and elimination of circulating tumor cells using multi-responsive nanosheet for malignant tumor therapy.

Tumor recurrence caused by metastasis is a major cause of death for patients. Thus, a strategy to manipulate the circulating tumor cells (CTCs, initiators of tumor metastasis ) and eliminate them along with the primary tumor has significant clinical significance for malignant tumor therapy. In this study, a magnet-NIR-pH multi-responsive nanosheet (Fe3O4@SiO2-GO-PEG-FA/AMP-DOX, FGPFAD) was fabricated to capture CTCs in circulation, then magnetically transport them to the primary tumor, and finally perform NIR-dependent photothermal therapy as well as acidic-environment-triggered chemotherapy to destroy both the CTCs and the primary tumor. The FGPFAD nanosheet consists of silica-coated ferroferric oxide nanoparticles (Fe3O4@SiO2, magnetic targeting agent), graphene oxide (GO, photothermal therapy agent), polyethylene glycol (PEG, antifouling agent for sustained circulation), folic acid (FA, capturer of CTCs) and antimicrobial-peptide-conjugated doxorubicin (AMP-DOX, agent for chemotherapy), in which the AMP-DOX was bound to the FGPFAD nanosheet via a cleavable Schiff base to achieve acidic-environment-triggered drug release for tumor-specific chemotherapy. Both in vitro and in vivo results indicated that the effective capture and magnetically guided transfer of CTCs to the primary tumor, as well as the multimodal tumor extermination performed by our FGPFAD nanosheet, significantly inhibited the primary tumor and its metastasis.

On-demand manipulation of tumorigenic microenvironments by nano-modulator for synergistic tumor therapy.

Proper manipulation of tumorigenic microenvironments has been considered as one of the most effective approaches for tumor therapy, which is still a challenge to be well performed. Herein, a nano-modulator was fabricated to manipulate the hypoxia, glucose, radicals and local temperature in tumor tissue as needed, which consists of hemoglobin (Hb) and ferric ion (Fe3+) co-conjugated polydopamine (PDA) as core, glucose oxidase (GOD) as shell, and folic acid (FA) modified polyethylene glycol (PEG) as corona. The PEG-FA corona not only protected Hb and GOD against protease in blood circulation, but serve as tumor targeting agent for tumor specific accumulation of the nano-modulator. The Hb is in charge of oxygen supply to reverse the hypoxic environment of tumor tissue, which promotes the function of GOD to achieve rapid glucose consumption and hydrogen peroxide generation. The polydopamine was employed to raise local temperature under NIR irradiation, meanwhile to continuously reduce Fe3+ to produce ferrous ions (Fe2+), which further catalyze hydrogen peroxide to cytotoxic hydroxyl radicals via Fenton reaction. Both in vitro and in vivo results showed excellent tumor inhibition and high survival rate of tumor-bearing mice after treatment by our nano-modulator, indicating this synergistic therapy via on-demand manipulation of various tumorigenic microenvironments could be a green approach for tumor treatment with high efficiency and minimum side effects.

Nanocomposite hydrogel with NIR/magnet/enzyme multiple responsiveness to accurately manipulate local drugs for on-demand tumor therapy.

Chemotherapy is one of the most commonly utilized approaches to treat malignant tumor. However, the well-controlled chemotherapy able to accurately manipulate local drugs for on-demand tumor treatment is still a challenge. Herein, a magnet and light dual-responsive hydrogel combining thermosensitive poly(N-acryloyl glycinamide) (PNAGA), doxorubicin (DOX) loaded and polyester (PE) capped mesoporous silica nanocarriers (MSNs) as well as Fe3O4 nanoparticles (Fe3O4 NPs) grafted graphene oxide (GO) was fabricated to address above issue. The Fe3O4 NPs and GO respectively serve as magnetothermal agent and photothermal agent to perform hyperthermia, meanwhile to generate chain motion of PNAGA with varying degrees under different conditions of magnetic field and/or NIR irradiation. This strategy not only allowed the gel-sol transition of the hydrogel by prior heating for tumor injection, but performed controllable release routes of DOX-MSNs-PE (DMP for short) nanocarriers to meet various requirements from different patients and the changing states of tumor. Furthermore, these escaped DMP nanocarriers could be taken by surrounding tumor cells, and then deliver their drug to these cells after rapid hydrolysis of the PE cap triggered by esterase, resulting in accurate chemotherapy. Both in vitro and in vivo results indicated that the PNAGA-DMP-Fe3O4@GO hydrogel combining well-controllable chemotherapy and hyperthermia can eliminate more than 90% tumor cells and effectively inhibit the tumor growth in mice model, demonstrating the great candidate of our hydrogel for accurate tumor therapy.

Substrate-independent polymer coating with stimuli-responsive dexamethasone release for on-demand fibrosis inhibition.

Tissue fibrosis caused by implantation of tissue engineering scaffolds is an urgent problem in clinical research. In this work, a substrate-independent coating with on-demand release of an antifibrotic drug has been fabricated to effectively address this issue. This coating was formed through a substrate-independent layer-by-layer (LBL) technique via a cationic polyelectrolyte (poly-diallyldimethylammonium, PDDA) and an anionic polyelectrolyte (poly-styrenesulfonate, PSS), where parts of PSS and PDDA were physically replaced by carboxyl functionalized polyethylene glycol grafted onto antifibrotic drug dexamethasone (DEX-PEG-COOH). Considering the easy generation of local inflammation after implantation, an ester bond was designed between PEG-COOH and DEX. Therefore, the overexpressed esterase under inflammatory conditions hydrolyzes the ester bond and thereby releases DEX from the film to inhibit fibrosis occurring in the tissue repair process. The in vivo capacity of this coating to restrain tissue fibrosis was investigated by a skin defect model using porous polycaprolactone (PCL) scaffolds as substrates. The experimental results showed that the fibrosis-related proteins (Col-I, TGF-ß and fibronectin) and the infiltration of myofibroblasts (α-SMA) of skin tissues in the coated PCL scaffold group were significantly lower than those in the blank control group and pure PCL scaffold group. Moreover, the histological evaluations showed that the coating group could significantly decrease the deposition of collagen and meanwhile promote the partial regeneration of skin appendages. These results successfully demonstrate that the universal coating prepared with a simple protocol would be an effective strategy to address the fibrosis issues during tissue engineering.

Intracellular Enzyme-Triggered Assembly of Amino Acid-Modified Gold Nanoparticles for Accurate Cancer Therapy with Multimode.

Multiple amino acid (glutamine and lysine)-modified gold nanoparticles a with pH-switchable zwitterionic surface were fabricated through coordination bonds using ferrous iron (Fe2+) as bridge ions, which are able to spontaneously and selectively assemble in tumor cells for accurate tumor therapy combining enzyme-triggered photothermal therapy and H2O2-dependent catalytic medicine. These gold nanoparticles showed electric neutrality at pH 7.4 (hematological system) to prevent endocytosis of normal cells, which could be positively charged at pH 6.8 (tumor microenvironment) to promote the endocytosis of tumor cells to these nanoparticles, performing great tumor selectivity. After cell uptake, the specific enzyme (transglutaminase) in tumor cells would catalyze the polymerization of glutamine and lysine to cause the intracellular assembly of these gold nanoparticles, resulting in an excellent photothermal property for accurate tumor therapy. Moreover, the Fe2+ ion could decompose excess hydrogen peroxide (H2O2) in tumor cells via the Fenton reaction, resulting in a large amount of hydroxyl radicals (·OH). These radicals would also cause tumor cell damage. This synergetic therapy associating with high tumor selectivity generated an 8-fold in vitro cytotoxicity against tumor cells compared with normal cells under 48 h incubation with 10 min NIR irradiation. Moreover, in vivo data from tumor-bearing nude mice models showed that tumors can be completely inhibited and gradually eliminated after multimode treatment combining catalytic medicine and photothermal therapy for 3 weeks. This system takes advantage of three tumor microenvironment conditions (low pH, enzyme, and H2O2) to trigger the therapeutic actions, which is a promising platform for cancer therapy that achieved prolonged circulation time in the blood system, selective cellular uptake, and accurate tumor therapy in multiple models.

Injectable colloidal hydrogel with mesoporous silica nanoparticles for sustained co-release of microRNA-222 and aspirin to achieve innervated bone regeneration in rat mandibular defects.

Nerve fibers and vessels play important roles in bone formation, and inadequate innervation in the bone defect area can delay the regeneration process. However, there are few studies aiming to promote innervation to engineer bone formation. Here, we report the development of an injectable thermoresponsive mesoporous silica nanoparticle (MSN)-embedded core-shell structured poly(ethylene glycol)-b-poly(lactic-co-glycolic acid)-b-poly(N-isopropylacrylamide) (PEG-PLGA-PNIPAM) hydrogel for localized and long-term co-delivery of microRNA-222 and aspirin (ASP) (miR222/MSN/ASP hydrogel). ASP was found to stimulate bone formation as previously reported, and miR222 induced human bone mesenchymal stem cell differentiation into neural-like cells through Wnt/ß-catenin/Nemo-like kinase signaling. In a rat mandibular bone defect, injection of the co-delivered MSN hydrogel resulted in neurogenesis and enhanced bone formation, indicating that the present injectable miR222- and ASP-co-delivering colloidal hydrogel is a promising material for innervated bone tissue engineering.

Substrate-Independent Coating with Persistent and Stable Antifouling and Antibacterial Activities to Reduce Bacterial Infection for Various Implants.

Implantation of biomedical devices accompanying infections has caused severe problems to public health that require feasible solutions. In this study, a simple approach is reported to fabricate a antimicrobial and antifouling dual-functional coating. This coating consists of a substrate-independent layer-by-layer (LBL) film formed by poly (diallyldimethylammonium) (PDDA) and poly (styrenesulfonate) (PSS), where parts of PSS and PDDA are physically substituted by hetero-bifunctional polyethylene glycol (PEG) ending with a carboxyl group and antimicrobial peptide (ε-Poly-l-lysine, ε-PL). This design (ε-PL-PEG-(PDDA/PSS)9 coating) exhibits not only potent antimicrobial activity against Gram-positive/negative bacteria but also superior antifouling activity on various substrates, including glass and plastic. Moreover, the antifouling and antibacterial performance can be maintained for a longer period of time under physiological environments even after physical damage of the surface due to the homogeneous interspersion and free migration of ε-PL-PEG-COOH in the LBL film. This allows the supplement of these molecules to the surface against molecule loss during usage. Both in vitro and in vivo (rodent subcutaneous infection model) studies show obvious reduction of the bacteria on the coated substrate and in the surrounding tissues with up to 3.2-log reduction, even after repeated usage. The inflammation around the implantation area is also significantly inhibited.

One-pot preparation of polymer microspheres with different porous structures to sequentially release bio-molecules for cutaneous regeneration.

Herein, we reveal a double emulsion method combining the sol-gel method to prepare poly(lactic-co-glycolic acid) microspheres with different porous structures for sequential release of two types of biomolecules. By controlling the ripening time of the emulsion, multiple interconnected chambers could be easily chosen to be either embedded in microspheres or opened to the surface. These two types of microspheres exhibited different kinetics for the release of both small molecules and proteins, where the release from microspheres with open pores (5 day over 90%) was much faster than the release from microspheres with embedded pores (25 day over 90%). After loading with interleukin-4 (IL-4) and melatonin, these microspheres were further encapsulated in a sodium alginate hydrogel to form a patch for cutaneous regeneration. The prepared patch was able to recruit alternatively activated (M2) macrophages in the early stage (fast release of IL-4) and promote the growth of blood vessels in the long term (slow release of melatonin), resulting in significantly enhanced cutaneous regeneration. These results also demonstrate the potential of this novel delivery system to deliver multiple therapeutics and achieve synergistic effects.