Search

PDF file - 206K, Supporting information includes fluorescence images of Bel-7402, MDA-MB-231 and MCF-7 cells after incubation with 2DG-SUC-ADM or free ADM at different time points, and dynamics and tumor-targeting ability of 2DG-ICG-Der-01 in nude mice

Background Malignant arrhythmias require drug therapy. However, most of the currently available anti-arrhythmic drugs have significant side effects. Ginsenoside Rg2 exhibits excellent cardioprotective effects and appears to be a promising candidate for cardiovascular drug development. So far, the oral toxicity and anti-arrhythmic effects of Rg2 have not been evaluated. Methods Acute oral toxicity of Rg2 was assessed by the Limit Test method in mice. Sub-chronic oral toxicity was determined by repeated dose 28-day toxicity study in rats. Anti-arrhythmic activity of Rg2 were evaluated in calcium chloride-induced arrhythmic rats. Anti-arrhythmic mechanism of Rg2 was investigated in arrhythmic rats and H9c2 cardiomyocytes, respectively. Results The results of toxicity studies indicated that Rg2 exhibited no single dose (10 g/kg) acute oral toxicity. And 28-day repeated dose treatment with Rg2 (1.75, 3.5 and 5 g/kg/d) demonstrated minimal, if any, sub-chronic toxicity. Serum biochemical examination showed that total cholesterol in the high-dose cohort was dramatically decreased, whereas prothrombin time was increased at day 28, suggesting that Rg2 might regulate lipid metabolism and have a potential anticoagulant effect. Moreover, pre-treatment with Rg2 showed anti-arrhythmic effects on the rat model of calcium chloride induced arrhythmia, in terms of the reduced duration time, mortality and incidence of malignant arrhythmias. The antiarrhythmic mechanism of Rg2 might be the inhibition of calcium influx through L-type calcium channels by suppressing the phosphorylation of Ca 2+ /calmodulin-dependent protein kinase II. Conclusion Our findings support the development of Rg2 as a promising anti-arrhythmic drug with less side effects for clinic use.

Electrospun cellulose nanofibers are promising biomaterials but are suffering from the use of unfavorable organic solvents during the electrospinning process. In this manuscript, we used the periodate oxidation—adipic acid dihydrazide crosslinking strategy to fabricate electrospun cellulose nanofibers. Periodate oxidation of cellulose generated water soluble aldehyde cellulose, which thus allowed for the electrospinning in aqueous solution and avoided the use of unfavorable organic solvents. The following crosslinking with adipic acid dihydrazide made the nanofibers water resistant. The results show that the prepared cellulose nanofiber mats show moderate wet mechanical strength around 1 MPa, are able to absorb water equal to 30 times of their own weight, can degrade gradually by hydrolysis, and are cytocompatible. These cellulose nanofibers are expected to find applications in biomedical fields such as wound healing and tissue regeneration.

Pectin-based drug delivery systems hold great potential for oral insulin delivery, since they possess excellent gelling property, good mucoadhesion and high stability in the gastrointestinal (GI) tract. However, lack of enterocyte targeting ability and premature drug release in the upper GI tract of the susceptible ionic-crosslinked pectin matrices are two major problems to be solved. To address these issues, we developed folic acid (FA)-modified pectin nanoparticles (INS/DFAN) as insulin delivery vehicles by a dual-crosslinking method using calcium ions and adipic dihydrazide (ADH) as crosslinkers. In vitro studies indicated insulin release behaviors of INS/DFAN depended on COOH/ADH molar ratio in the dual-crosslinking process. INS/DFAN effectively prevented premature insulin release in simulated GI fluids compared to ionic-crosslinked nanoparticles (INS/FAN). At an optimized COOH/ADH molar ratio, INS/DFAN with FA graft ratio of 18.2% exhibited a relatively small particle size, high encapsulation efficiency and excellent stability. Cellular uptake of INS/DFAN was FA graft ratio dependent when it was at/below 18.2%. Uptake mechanism and intestinal distribution studies demonstrated the enhanced insulin transepithelial transport by INS/DFAN via FA carrier-mediated transport pathway. In vivo studies revealed that orally-administered INS/DFAN produced a significant reduction in blood glucose levels and further improved insulin bioavailability in type I diabetic rats compared to INS/FAN. Taken together, the combination of dual crosslinking and FA modification is an effective strategy to develop pectin nano-vehicles for enhanced oral insulin delivery.

Pectin nanofiber mats are promising tissue engineering scaffolds but suffer from poor cell infiltration. In this study, gelatin, a collagen derived cell adhesive protein, was used to crosslink the electrospun nanofibers of periodate oxidized pectin. Cell culture experiment results demonstrated that cells were able to grow into the gelatin-crosslinked pectin nanofiber mats rather than only spread on mat surface. The nanofiber mats showed moderate mechanical strength, with a maximum tensile strength of up to 2.3 MPa, an ultimate tensile strain of up to 15%, and were capable of degrading gradually over 4 weeks or even longer periods in simulated body fluids. Thus, gelatin-crosslinked pectin nanofiber mats hold a great potential for soft tissue regeneration.

Polysaccharides display poor cell adhesion due to the lack of cell binding domains. This severely limits their applications in regenerative medicine. This study reports novel cross-linked pectin nanofibers with dramatically enhanced cell adhesion. The nanofibers are prepared by at first oxidizing pectin with periodate to generate aldehyde groups and then cross-linking the nanofibers with adipic acid dihydrazide to covalently connect pectin macromolecular chains with adipic acid dihydrazone linkers. The linkers may act as cell binding domains. Compared with traditional Ca2+-cross-linked pectin nanofibers, the pectin nanofibers with high oxidation/cross-linking degree exhibit much enhanced cell adhesion capability. Moreover, the cross-linked pectin nanofibers exhibit excellent mechanical strength (with Young’s modulus ∼10 MPa) and much enhanced body degradability (degrade completely in 3 weeks or longer time). The combination of excellent cell adhesion capability, mechanical strength, and body degradability...

Polysaccharides including pectin, alginate and chitosan are fabricated into dressings of micrometer-scaled architecture (micro- fiber or particle) and widely applied in wound treatments clinically. This work characterized and compared the properties of electrospun nanofibrous dressings of these polysaccharides. We found that although the three polysaccharide nanofiber mats had comparable mechanical strength and vapour permeability, the pectinate nanofiber mat could absorb 1.2 times and 3.6 times more exudates than the alginate and chitosan nanofiber mats, respectively, within less time. Moreover, the pectinate nanofiber mat showed much higher antibacterial activity (73.1%) than the alginate and chitosan nanofiber mats (11.8% and 17.1%, respectively). Further examinations demonstrated that the superior absorbency and antibacterial activity of the pectinate nanofiber mat were associated with the moderate extent of swelling of pectinate nanofibers under hydrated conditions. All these results suggest that the pectinate nanofiber mat might be a superior wound dressing to the alginate and chitosan nanofiber mats.

Neutral polysaccharides such as konjac glucomannan, starch and pullulan are abundant in nature and have unique property. Their nanofibers hold great potential for biomedicine, which however, are seldom applied in the field due to the lack of crosslinking method. In this work, we report a periodate oxidation - adipic acid dihydrazide (ADH) crosslinking strategy to prepare robust and biocompatible neutral polysaccharide nanofibers. Neutral polysaccharides with adjacent dihydroxyl groups are firstly partially oxidized with periodate to give dialdehyde polysaccharides, and their electrospun nanofibers are then crosslinked with ADH to form dihydrazone crosslinkers. The resulting crosslinked neutral polysaccharide nanofibers exhibit high water resistance and excellent mechanical properties because of the high reactivity of Schiff base crosslinking reaction. Moreover, the crosslinked neutral polysaccharide nanofibers show good biocompatibility due to the low toxicity of ADH. These robust and biocompatible neutral polysaccharide nanofibers are expected to seek extensive applications in a variety of biomedical fields.

Silver-containing dressings are widely used for the treatment of infected wounds in clinics, but the potential risks of heavy metals are still a common concern. In this study, we prepared a type of electrospun starch nanofiber mat containing the antimicrobial peptide e-poly-lysine (Starch-EPL) and compared its relevant properties with a representative silver-containing dressing 3M™ Tegaderm™ Alginate Ag (Alginate-Ag). SEM, FTIR and EDAX results show the two samples have similar fiber structures and are loaded with antibacterial agents. The comparison results indicate that the Starch-EPL nanofiber mat has equivalent permeability and absorbency with Alginate-Ag but higher mechanical property and wettability. Moreover, the Starch-EPL nanofiber mat has comparable antibacterial activity against both Gram-negative and Gram-positive bacteria with Alginate-Ag, but markedly better biocompatibility than that. The Starch-EPL nanofiber mat can inhibit the growth of bacteria for at least 14 days by sustainably releasing EPL, showing great potential as a long-term antibacterial dressing. All these results demonstrate that the Starch-EPL nanofiber mat may be a good candidate to replace the traditional silver-containing dressings.

Silver nanoparticles (AgNPs) have a wide antimicrobial spectrum and low incidence of resistance. They have been widely incorporated into wound dressings for antimicrobial purpose. However, these wound dressings suffer from the accompanied cytotoxicity. It is important but challenging for them to reduce the cytotoxicity without compromising antimicrobial activity, while the affecting factors are unknown. In this work, we incorporated AgNPs into starch nanofiber mats with the in situ reduction method, and investigated the structure and property of the composite nanofiber mats in detail. We found that the cytotoxicity and antibacterial activity of the starch/AgNPs composite nanofiber mats are both affected by the release behavior of silver from the mats, while of various stages and governing factors. The cytotoxicity of the mats depends on the silver release rate at the early stage, which is governed by both the size and content of the AgNPs. The antibacterial activity is more related to the silver release rate at the later stage and is determined mainly by the content of AgNPs. By optimizing the size and content of AgNPs, we found a safe window and obtained starch/AgNPs composite nanofiber mats with good antibacterial activity and excellent cytocompatibility as well. The composite nanofiber mats also showed moderate wet strength (1–2 MPa), high liquid absorption capability (19–34 times of their own weights) and suitable vapor permeability [0.22–0.26 g/(cm2·24 h)]. These starch/AgNPs composite nanofiber mats are ideal candidates for the treatment of infected and exuding wounds.

Particle preloading method by first loading proteins onto nano- or microparticles and then integrating these particles into electrospun polyester nanofibers has been widely used to encapsulate therapeutic proteins into polyester nanofibers. However, poor method design has resulted in unsatisfactory protein delivery performance. For example, the harsh conditions involved in preloading procedures damage the bioactivities of proteins, the improper integration leads to an uneven distribution of particles in nanofibers or insecure attachment of particles to nanofibers, producing uncontrolled protein release profiles. This study aimed to improve the protein delivery performance of polyester nanofibers by rationally designing a particle preloading method. Positively charged chitosan nanoparticles (CNPs) were used as carriers to adsorb negatively charged proteins in mild conditions and as primary barriers for protein release. The polar CNPs were then homogeneously dispersed in a polar polyester solution and subjected to electrospinning. Microscope observations indicated that CNPs were homogeneously embedded within polyester nanofibers. In vitro release behaviour and cell studies showed that proteins retained their bioactivity and could release from polyester nanofibers in a sustained manner for more than 4 weeks without any initial burst. Epidermal growth factor encapsulated in polyester nanofibers enhanced diabetic wound healing in vivo, demonstrating an application potential in biomedicine. Other properties of the nanofibers, including composition, wettability, cytotoxicity, and cell adhesion and spreading, were examined in detail as well.

Its hydrophilic property and poor water resistance prevent the application of starch in electrospun nanofibers for biomedical applications. In this paper, we apply a periodate oxidation-adipic acid dihydrazide crosslinking strategy to electrospun starch nanofibers and develop a new nanofiber material with excellent mechanical strength, superior water resistance, and excellent cytocompatibility. The crosslinked starch nanofiber membranes exhibit a Young's modulus up to 2.65 MPa in the wet state, can maintain 91.0% of their initial mass after four weeks' incubation in simulated body fluid, and do not cause toxicity to L929 fibroblast cells. The control nanofibers prepared with a conventional glutaraldehyde crosslinking strategy show only a 60 kPa Young's modulus, retain only 31.9% of their initial mass after four weeks in simulated body fluid, and cause toxicity to cells. The crosslinked starch nanofibers with high mechanical strength, excellent water resistance and good biocompatibility are promising for biomedical applications.

Chronic wounds are of high incidence, difficult to heal, and can cause serious consequences if not properly treated. Doxycycline (DCH) is a broad-spectrum antibiotic and matrix metalloproteinases inhibitor, which has prominent efficacy for chronic wound treatment. Topical DCH treatment is the common administration route for chronic wounds in clinic but may result in low therapeutic efficacy and cause skin irritation at high DCH concentration, since it is difficult to control local drug concentration in the wounds and maintain the effective DCH concentration for a long time. In this study, we prepared DCH-encapsulated polylactide (DCH/PLA) nanofibers by a simple electrospinning method. Imaging studies showed that smooth and continuous DCH/PLA nanofibers with homogeneous DCH distribution were obtained at varied DCH loading content in the range of 5–30%. Mechanical property, water vapour permeability and absorbency of these nanofibers could meet the requirement as wound dressings. By adjusting DCH loading content, the wettability of the nanofibers could be transferred from hydrophobic to hydrophilic, and the release rate of DCH could be controlled in a sustained manner from three days to two weeks. Results of cytotoxicity and antibacterial test indicated that DCH/PLA nanofibers showed good cytocompatibility to L929 mouse fibroblast cells and exhibited positive antibacterial activity against Escherichia coli , suggesting its ability to treat/prevent infectious wounds. For full-thickness wound treatment of diabetic rats, DCH/PLA nanofiber mats can speed up wound healing to a higher extent than topical DCH treatment, due to the sustained release of DCH with less side effects. Our results indicate that DCH/PLA nanofiber mats hold great potential as wound dressings for chronic wound treatment.

Nanofibers with well-dispersed Ag nanoparticles (AgNPs) are promising for some applications. Dispersion electrospinning is a straightforward preparation method but is suffered from the negative effects that the further treatments of nanofibers after electrospinning may bring to the dispersed AgNPs. In this study, we report a post reduction method to fabricate nanofibers with well-dispersed AgNPs. Crosslinked nanofibers of a hydrophilic polysaccharide, pectin, are used. When being immersed in the aqueous solution of AgNO3, the crosslinked pectin nanofibers swell, allowing Ag+ ions enter inside. The surrounding crosslinked pectin macromolecules functionalize as in situ reducing reagents to reduce Ag+ ions, nucleating the crystallization of AgNPs locally. X-ray diffraction characterizations indicate that the formed AgNPs are face-centered cubic crystalline. Results of optical imaging, UV-vis spectroscopy, scanning electron microscopy (SEM), electron dispersive spectrometry as well as transmission electron microscopy (TEM) indicate that the content and size of AgNPs increase with the increase of AgNO3 concentration and incubation time. SEM and TEM results show that the dispersion of the AgNPs does not affect the nanofibrous structure and size of the crosslinked pectin nanofibers. TEM results also demonstrate that AgNPs distribute homogeneously along both the length and diameter direction of nanofibers. The composite nanofibers can sustainably release silver for 4 weeks and inhibit the growth of Escherichia coli for 7 days, showing great potential as long-term antibacterial materials. The method may also be used to disperse AgNPs in other hydrophilic nanofibers which need further treatments after electrospinning.

Photodynamic therapy (PDT) has recently been proposed as an innovative approach to combat multi-drug resistant (MDR) bacteria. To improve the penetration depth of current PDT, a core-shell upconversion nanoparticle (UCNP) based PDT system, composed of a cationic N-octyl chitosan (OC) coated UCNP loaded with the photosensitizer zinc phthalocyanine (OC-UCNP-ZnPc), was constructed to enhance the antibacterial efficacy against MDR bacteria in deep tissue. The core-shell UCNPs displayed a higher upconversion fluorescence efficiency compared to the inner UCNP core. Dual antibacterial activities induced by chitosan and PDT-induced ROS were demonstrated, independent of the bacterial species. In particular, these nanoconstructs exhibited excellent antibacterial effects on the MDR bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and β-lactamase-producing Escherichia coli. In vivo antibacterial therapy for murine MRSA-infected abscesses in the deep tissue (1 cm) strongly confirmed the outstanding anti-MRSA efficacy of OC-UCNP-ZnPc. Our results indicated that the OC-UCNP-ZnPc based PDT system triggered by deep-penetrating NIR light has a prominent antibacterial effect on MDR bacteria, which could be a promising strategy for deep-tissue infections.

In this study, an amphiphilic copolymer folate-succinyl-methionine-chitosan-octyl (FSMCO) was successfully synthesized step by step for self-assembling polymeric micelles. The copolymers formed micelle-like nanoparticles by their amphiphilic characteristics and structures were examined by UV-Vis absorption and Fourier transform spectroscopy. The sizes of blank and ICG derivative-loaded micelles measured by dynamic light scattering were about 170 and 140 nm, respectively, which were spherical in shape with an average zeta potential of −10 mV. Further studies on the stability showed that the micellar solutions maintain their sizes at room temperature for 1 month without distinct aggregation or dissociation. ICG derivative was much better photostable after being entrapped by the new carrier. The prepared FSMCO micelles displayed a good drug loading content (11.7%), entrapment efficiency (66.5%) and sustained release rate for the model drug fluorescein. The copolymers demonstrated weeny cytotoxicity toward Bel-7402, L02 and A549 cells when incubated for 2 d. Ligands modified micelles endowed preferable cell targeting capability and beautiful cell inhibition of HCPT-FSMCO on Bel-7402 tumor cells. This kind of polymeric micelles may be a promising nanovehicle in delivering near-infrared dyes for tumors imaging and chemotherapeutic drugs for cancer therapeutics.

Uniform gold nanostars (Au NS) were conjugated with cyclic RGD (cRGD) and near infrared (NIR) fluorescence probe (MPA) or anti-cancer drug (DOX) to obtain multi-functional nanoconstructs, Au-cRGD-MPA and Au-cRGD-DOX respectively. The NIR contrast agent Au-cRGD-MPA was shown to have low cytotoxicity. Using tumor cells and tumor bearing mice, these imaging nanoparticles demonstrated favorable tumor-targeting capability mediated by RGD peptide binding to its over-expressed receptor on the tumor cells. The multi-therapeutic analogue, Au-cRGD-DOX, integrates targeting tumor, chemotherapy and photo-thermotherapy into a single system. The synergistic effect of photo-thermal therapy and chemotherapy was demonstrated in different tumor cell lines and in vivo using S180 tumor-bearing mouse models. The viability of MDA-MB-231 cells was only 40 % after incubation with Au-cRGD-DOX and irradiation with NIR light. Both tail vein and intratumoral injections showed Au-cRGD-DOX treated mice exhibiting the slowest tumor increase. These results indicate that the multifunctional nanoconstruct is a promising combined therapeutic agent for tumor-targeting treatment, with the potential to enhance the anti-cancer treatment outcomes.

We reported crosslinking of electrospun nanofibers of three representative pectins (high-methoxylated, low-methoxylated, low-methoxylated and amidated pectin) and characterization of the crosslinked nanofibers. One mono-crosslinking strategy and two dual-crosslinking strategies were developed. Mono-crosslinking is achieved using calcium ions (Ca2+) to crosslink carboxylate ions in galacturonic acid residues. Dual-crosslinking is achieved using covalent crosslinking reagents glutaraldehyde (GLU) or adipic acid dihydrazide (ADH) to further crosslink hydroxyl groups or carboxylate ions after Ca2+ crosslinking. Mechanical tests and degradation experiments indicated pectin structure affected mechanical and degradation properties of Ca2+-crosslinked nanofibers remarkably. Subsequent GLU crosslinking improved their mechanical strength moderately but did not inhibit their degradation, while subsequent ADH crosslinking improved their mechanical strength and slowed down their degradation dramatically. Cell studies demonstrated that most crosslinked pectin nanofibers were of no obvious cytotoxicity, and both ADH crosslinking and high degree of methoxylation facilitated cell adhesion and proliferation on pectin nanofiber mats.

Tumor-targeted drug delivery is an attractive strategy in cancer treatment. Our previous study demonstrated that modified adenovirus has strong tumor targeting ability and less toxicity to surrounding normal tissue. In this study, Paclitaxel (PTX), a widely used clinical anticancer drug, was conjugated to folate-modified adenovirus (Ad) nanoparticles by using succinic anhydride and Fmoc-Glu(OtBu)–OH linkers to form two prodrugs, FA-Ad-Suc-PTX and FA-Ad-ICG02-Glu-PTX. Near-infrared (NIR) fluorescent dye ICG-Der-02 was attached to –NH 2 –Glu(OtBu)-PTX for in vivo optical imaging. In vitro and acute toxicity study demonstrates the low toxicity of the prodrug FA-Ad-Suc-PTX and FA-Ad-ICG02-Glu-PTX compared to the free drug. The dynamic behaviors and targeting ability of FA-Ad-ICG02-Glu-PTX on MDA-MB-231 tumor-bearing mice were investigated by NIR fluorescence imaging. The result show that PTX-conjugated Ad vector could enhance the targeting and residence time in tumor site. In vitro and in vivo studies demonstrate that Coxsackie adenovirus receptor (CAR) or foliate receptor (FR)-mediated uptake of FA-Ad-loaded PTX induced highly anti-tumor activity. The results support the potential of using chemically modified Ad vector as drug-loaded tumor-targeting delivery system.

CdHgTe/SiO(2) nanoparticles were prepared by SiO(2) capping on the surface of CdHgTe QDs. The characteristics, such as optical spectra, photostability, size and cell toxicity were investigated. The dynamic distribution of CdHgTe/SiO(2) nanoparticles was in vivo monitored by near infrared fluorescence imaging system. CdHgTe/SiO(2) nanoparticles acted as a novel fluorescence probe have a maximum fluorescence emission of 785 nm and high photo-stability. The hydrodynamic diameter of CdHgTe/SiO(2) nanoparticles could be adjusted to 122.3 nm. Compared to CdHgTe QDs, inhibitory effects of CdHgTe/SiO(2) nanoparticles on proliferation of HCT116 cells decreased to a certain extent. CdHgTe/SiO(2) nanoparticles had their specific dynamic distribution behavior, which provided new perspectives for bio-distribution of nanoparticles.

CdHgTe-folate conjugates, acting as novel active-targeting fluorescence probes, were prepared by covalent conjugation of CdHgTe QDs and folic acid. Their characteristics, such as optical spectra, stability and cancer cell targeting were investigated in detail. The fluorescence wavelength of CdHgTe-folate conjugates was 790 nm and a full width at half-maximum (FWHM) of them was 50-70 nm. Their fluorescence stability could satisfy the need of long and continuous fluorescence imaging. The in vivo dynamic bio-distribution of CdHgTe-folate conjugates in S180 tumor beard mouse model was monitored by a NIR imaging system. The resultes indicated that CdHgTe-folate conjugates targeted to tumor effectively. The high fluorescence intensity together with targeting effect makes CdHgTe-folate conjugates promising candidates for imaging, monitoring and early diagnosis of cancer at molecular and cell level.

Nanofibers of natural polymers represent an essential class of materials in biomedicine. Pectin is a plant-sourced anionic polysaccharide widely used in food products and biomedicine owning to its abundance, biocompatibility and inherent bioactivity. However, current electrospun pectin nanofibers are suffered from high content of carrier polymer, which may lead to low integrity and mechanical strength as well as in vivo toxicity. We report here a strategy to reduce the content of carrier polymer, polyethylene oxide (PEO) in our study, in pectin nanofibers, via electrospinning at low loading followed with selective washing. With improved electrospinning condition, we first enabled electrospinning of pectin nanofibers at low PEO loading. Then the PEO was removed by washing with a selective solvent to give pectin nanofibers containing only 1.5% PEO. The strategy was versatile to pectins from various sources and of various degree of esterification. The pectin nanofibers exhibited Young's modulus as high as 358.5MPa. In view of their rich bioactivity, the pectin nanofibers of low content of carrier polymer are promising materials for a wide range of biomedical applications.

Galactose residues could be specifically recognized by the asialoglycoprotein receptor (ASGPR) which is highly exhibited on liver tissues. However, ASGPR has not been widely investigated on different tumor cell lines except for hepatoma carcinoma cells, which motivates us to investigate the possibility of galactose serving as a board tumor ligand. In this study, a galactose (Gal)-based probe conjugated with fluorescence dye MPA (Gal-MPA) was constructed for the evaluation of tumor affinities/targeted ability on different tumor cell lines. In the vitro cell study, it was indicated that the fluorescence probe Gal-MPA displayed higher cell affinity to tumor cells (HepG2, MCF-7 and A549) than that of the normal liver cells l02. In the vivo dynamic study of Gal-MPA in tumor-bearing mice (HepG2, MCF-7, A549, HCT116, U87, MDA-MB-231 and S180), it was shown that its high tumor targeted ability with the maximal tumor/normal tissue ratio reached up to 6.8. Meanwhile, the fast tumor-targeted ability within 2 hours and long retention on tumor site up to 120 hours were observed. Our results demonstrated that galactose should be a promising broad ligand for multiple tumor imaging and targeted therapy. Subsequently, Gal was covalently conjugated to doxorubicin (DOX) to form prodrug Gal-DOX for tumor targeted therapy. The therapeutic results of Gal-DOX than DOX being better suggested that galactosylated prodrugs might have the prospective potential in tumor targeted therapy.

In this study, we have prepared tumor-targeted hydrophilic UCNPs by coating folate-modified amphiphilic SOC polymer on the surface of OA-UNCPs through hydrophobic interaction. The produced FASOC-UCNPs have excellent optical properties and good dispersibility in aqueous solution. TEM image and FTIR spectra confirm the successful surface modification of OA-UCNPs and folate-conjugation on the UCNPs. Folate-conjugated UCNPs possess active-targeting ability mediated by FR, compared with passive-targeted SOC-UCNP taken up by tumors via the EPR effect. Singlet oxygen production in cancer cells induced by FASOC-UCNP-ZnPc demonstrates the great potential of the nanocomplex as a novel PDT agent based on UCNPs.

Mucin 1 (MUC1) is a cell surface mucin broadly expressed in mucosal tissues. The aberrant expression of MUC1 under-glycosylated forms has been reported in various carcinomas of the epithelium, such as breast, pancreatic and ovarian cancers. Using the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology, aptamers previously selected against MUC1 glycoprotein with high affinities and specificities. In this study, we developed two targeted near-infrared fluorescent probes for tumor in-vivo diagnostics using a MUC1 aptamer(APT) as targeted ligand and near-infrared fluorescent dye (ICG-Der-02) as labelling. MUC1 aptamer conjugated ICG-Der-02 (APT-ICG-Der-02) displayed a great selectivity to MUC1 positive cell line MCF7 and MCF7 xenograft-bearing nude mice. To improve the high targeting of the probe to the tumor cells, PEG, with high biocompatibility, non immunogenicity and long circulation, was conjugated to the probe .The new probe (APT-PEG-ICG-Der-02) showed better tumour uptake and clearance, and also displayed a great selectivity to MCF7 tumor-bearing nude mice. Data obtained demonstrate a high potential of the targeted near-infrared fluorescent probes in cancer early diagnosis.

Asialoglycoprotein receptors distributing on the surface of hepatic parenchymal cells could specifically recognize galactose residues. Therefore, galactose residues can be applied in hepatocellar carcinoma targeted therapy through binding to the asialoglycoprotein receptors. A drug carrier containing of near infrared (NIR) fluorescence dye (MPA) and galactose was constructed by covalently conjugation process and named as GAL-MPA. The optical properties, cell viability, cell affinity and in vivo bio-distribution of this drug carrier were evaluated respectively. The results demonstrated that the drug carrier was provided with NIR fluorescence after conjugated with MPA. The low bio-toxicity and high hepatic cells affinity facilitated this drug carrier for in vivo biomedical application. Finally, the in vivo dynamic distribution of GAL-MPA confirmed this drug carrier was a promising candidate for tumor-targeting imaging and therapy.

Adriamycin (ADM) has been effective against many types of solid tumors in clinical applications. However, its use is limited because of systemic toxicities, primarily cardiotoxicity, and multidrug resistance. In this study, a new active receptor-mediated complex, ADM conjugated with 2-amino-2-deoxy-d-glucose and succinic acid (2DG–SUC–ADM), was designed to target tumor cells through glucose transporter 1 (GLUT1). MTT assay and confocal images showed that the complex had better inhibition rate to tumor cells and low toxicity to normal cells. Most importantly, the complex displayed a potential to reverse overcome multidrug resistance in cancer cells, with more complex transported into the nucleus of tumor cells. Our in vivo experiments also showed that this new complex could significantly decrease organ toxicity and enhance the antitumor efficacy compared with free ADM, indicating a promising drug of 2DG–SUC–ADM for targeted cancer therapy. Cancer Res; 73(4); 1362–73. ©2012 AACR.

The aim of this study is to present a multifunctional nanoplatform which consists of upconversion nanoparticles (UCNPs) and photosensitizer Zinc (II) phthalocyanine (ZnPc) for deep tumor PDT.

Two major challenges of current photodynamic therapy (PDT) are the limited tissue penetration of excitation light and poor tumor-selectivity of the photosensitizer (PS). To address these issues, we developed a multifunctional nanoconstruct consisting of upconversion nanoparticles (UCNPs) that transform near-infrared (NIR) light to visible light and a photosensitizer zinc(II) phthalocyanine (ZnPc). Folate-modified amphiphilic chitosan (FASOC) was coated on the surface of UCNPs to anchor the ZnPc close to the UCNPs, thereby facilitating resonance energy transfer from UCNPs to ZnPc. Confocal microscopy and NIR small animal imaging demonstrated the enhanced tumor-selectivity of the nanoconstructs to cancer cells that overexpressed folate receptor. Reactive oxygen species (ROS) generation in cancer cells under a 1-cm tissue was higher upon excitation of UCNPs with the 980 nm light than that with 660 nm irradiation. In vivo PDT treatments for deep-seated tumors demonstrated that NIR light-triggered PDT based on the nanoconstructs possessed remarkable therapeutic efficacy with tumor inhibition ratio up to 50% compared with conventional visible light-activated PDT with a noticeable reduced tumor inhibition ratio of 18%. These results indicate that the multifunctional nanoconstruct is a promising PDT agent for deep-seated tumor treatment and demonstrate a new paradigm for enhancing PDT efficacy.

Bombesin (BBN), an analog of gastrin-releasing peptide (GRP), of which the receptors are over-expressed on various tumor cells, is able to bind to GRP receptor specifically. In this study, a near-infrared fluorescent dye (MPA) and polyethylene glycol (PEG) were conjugated to BBN analog to form BBN[7-14]-MPA and BBN[7-14]-SA-PEG-MPA. The successful synthesis of the two probes was proved by the characterization via sodium dodecylsulfate-polyacrylamide gel electrophoresis, infrared and optical spectra. Cellular uptakes studies indicated that BBN-based probes were mediated by gastrin-releasing peptide receptors (GRPR) on tumor cells and the PEG modified probe had higher affinity. The dynamic distribution and clearance investigations showed that the BBN-based probes were eliminated by the liver-kidney pathway. Furthermore, both of the BBN-based probes displayed tumor-targeting ability in GRPR over-expressed tumor-bearing mice. The PEG modified probe exhibited faster and higher tumor targeting capability than BBN[7-14]-MPA. The results implied that BBN[7-14]-SA-PEG-MPA could act as an effective fluorescence probe for tumor imaging.

Gold nanoclusters (NCs) were functionalized as a fluorescent probe and a pro-drug intended for tumor diagnosis and therapy. Firstly, Au NCs were conjugated with methionine (Met) and MPA, a near-infrared (NIR) fluorescent dye, giving a probe, Au-Met-MPA. The tumor targeting capability endowed by Met as well as low cytotoxicity of this contrast agent and its clinical potential for tumor targeting imaging were demonstrated in vitro and in vivo. Secondly, Doxorubicin (DOX), a widely used clinical anti-cancer drug, was immobilized on the methionine modified Au NCs to form a pro-drug, Au-Met-DOX. The enhanced tumor affinity and improved anti-tumor activity of this pro-drug were demonstrated. Results in this study suggest not only the prospect of non-toxic Au NCs modified with functional ligands for tumor-targeted imaging, but also confirm the promising future of Au NCs as a core for the design of pro-drug in the field of cancer therapy.

10-Hydroxycamptothecin (HCPT) is an effective anticancer drug against various types of solid tumors. But the antitumor efficacy of HCPT is far from satisfactory because of its poor physicochemical properties, short circulating half-life, low stability, and nonspecific toxicity to normal tissues. Therefore, a targeted delivery strategy for HCPT to pathological sites is eagerly needed to overcome these limitations. The folate-modified N-succinyl-N'-octyl chitosan (folate-SOC) micelle was chosen in this study and served as the targeted delivery system for HCPT to improve the antitumor efficacy. The water-insoluble anticancer drug HCPT was encapsulated into the folate-SOC micelles by the dialysis method. The near-spherical HCPT-loaded folate-SOC (HCPT/folate-SOC) micelles were formed in aqueous media with diameter of about 100-200 nm. The HCPT/folate-SOC micelles displayed a good stability, reasonable drug-loading content (about 10%), and sustained release behavior for the water-insoluble HCPT. Compared with free HCPT, HCPT/folate-SOC micelles exhibited a significant enhancement of cellular uptake, higher cytotoxicity against folate receptor positive tumor cell (Bel-7402), excellent tumor-targeting capability and substantially better antitumor efficacy on the nude mice bearing Bel-7402 xenografts. These results demonstrate the potential of folate-SOC micelles as long-term stable and effective drug delivery systems in cancer therapy.

Upconversion nanoparticles (UCNPs) as a new kind of biological luminescence materials have many advantages comparing with organic fluorescence probes and semi-conductive quantum dots, such as sharp fluorescence emission, long emission lifetimes, high optical and chemical stability and low toxicity, especially low auto-fluorescence background and deep tissue penetration under near-infrared (NIR) light excitation for bioimaging. Herein, we demonstrate a facile approach to transfer UCNPs from hydrophobic to hydrophilic and the use of these UCNPs for cell imaging. Oleic acid-capped UCNPs based on NaYF 4 were synthesized and modified with amphiphilic chitosan derivative through hydrophobic interaction. The as-prepared chitosan coated UCNPs with an average diameter of 35 nm were mono-dispersed in aqueous solution and possess good optical properties upon NIR light excitation. Cell viability assays indicated the low cytotoxicity and good biocompatibility of chitosan-coated UCNPs. Cell imaging results demonstrated that chitosan-coated UCNPs had great potential for bioimaing and biolabeling. Our work suggests a feasible method to modify OA-UCNPs with amphiphilic polymer and the promise of chitosan-based UCNPs for bioimaging application.

CdHgTe/SiO 2 nanoparticles were prepared by SiO 2 capping on the surface of CdHgTe quantum dots (QDs). The characteristics, such as optical spectra, size and optical stability were investigated. The size of CdHgTe/SiO 2 nanoparticles could be larger than 100 nm after CdHgTe QDs capped with SiO 2 . CdHgTe/SiO 2 nanoparticles acted as a novel fluorescence probe have a maximum fluorescence emission of 790 nm and a full width at half-maximum (FWHM) of 50-70 nm. The in vivo fluorescence imaging of CdHgTe/SiO 2 nanoparticles in mouse model indicated the nanoparticles could be passively targeting to lung and liver. CdHgTe/SiO 2 nanoparticles offer new perspectives for size dependent bio-dstribution studies in living body.

Near infrared (NIR) CdHgTe/CdS quantum dots (QDs) were successfully prepared by a green synthetic route. The characteristics such as morphology, size, spectra, stability and toxicity were investigated in detail. The fluorescence wavelength of CdHgTe/CdS QDs could be adjusted to the NIR range (812nm), which made the in vivo NIR imaging possible. The in vivo dynamic biodistribution of CdHgTe/CdS QDs in a mouse model was monitored by an NIR imaging system. Results indicated that CdHgTe/CdS QDs with a diameter of about 5.8nm targeted to spinal column effectively. Further imaging of the dissected spine disclosed that QDs targeted to vertebra rather than spinal cord. The high fluorescence intensity together with targeting effect makes CdHgTe/CdS QDs particular candidates for imaging purposes in experimental animal models of vertebral injury.

Treatment of malignant brain tumors continues to challenge scientists and clinicians alike. Location of these tumors within the central nervous system (CNS), which is considered a "privileged" organ, can prevent the penetration of chemotherapeutic agents through the blood–brain barrier (BBB). To overcome this limitation, nanoparticles are taken up and transported by macrophage and then delivered directly into the CNS. In this study, we used macrophage to uptake the folate-targeted bifunctional micelles loaded with near-infrared (NIR) dye ICG-Der-01 and investigate the dynamic bio-distributions of macrophage after intravenous injection into tumor-bearing mice. In vitro cellular experiments by confocal microscopy indicated that the uptake of micelles in macrophage was greatly enhanced due to the folate receptor overexpression. Dynamic bio-distributions of macrophage showed a rapid clearing rate through the liver intestine pathway. In conclusion, macrophage could potentially be used as nanoparticle drug carriers and require further investigation.

Stearyl-2-amino-2-deoxyglucose (2-DG) modified nanostructured lipid carriers (NLC) were developed as novel vehicles for tumor-targeted delivery. The NLC were prepared using a melted-ultrasonic method, with glyceryl monostearate (MS) as a solid lipid and oleic acid (OA) as a liquid lipid. The physical properties of the NLC, including particle size, zeta potential, surface morphology, crystal structure, and storage stability, were characterized by standard methods. 2-DG, a glucosamine derivative, serving as a broad tumor targeting ligand, was conjugated to the surface of NLC (2-DG-NLC) for targeted delivery. Fluorescent dyes (fluorescein and cypate) and anticancer drug (paclitaxel, PTX) were used as model drugs to optimize the constituents of the NLC for drug entrapment efficiency and in vitrodrug release. The dynamic behavior of 2-DG-NLC in normal mice was investigated with a near infrared (NIR) fluorescence imaging system. The in vitro and in vivo tumor targeting capabilities of 2-DG-NLC were evaluated in MCF-7 tumor cells and tumor bearing mice, respectively. Results demonstrated that 2-DG-NLC actively and efficiently accumulated at the site of the tumor. Paclitaxel encapsulated 2-DG-NLC (2-DG-PTX-NLC) had good antitumor effectiveness and low toxicity in MCF-7 tumor bearing mice. The study indicates the broad potential of this carrier for tumor diagnosis as well as for targeted chemotherapy.

Upconversion nanoparticles (UCNPs) have attracted much attention as potential photosensitizer carriers for photodynamic therapy (PDT) in deep tissues. In this study, hydrophilic UCNPs were prepared by coating amphiphilic chitosan (N-succinyl-N′-octyl chitosan, SOC) on the surface of hydrophobic oleic acid-capped NaYF4 UCNPs (OA-UCNPs). Water-insoluble photosensitizer zinc(II) phthalocyanine (ZnPc) was loaded into the SOC-coated UCNPs (SOC-UCNPs) via hydrophobic interactions to form a novel drug delivery system for in vivo deep tissue PDT triggered by near-infrared (NIR) light. The ZnPc-loaded SOC-UCNPs exhibited good dispersibility, excellent optical properties and good photostability. Under NIR light irradiation, the measurement of singlet oxygen production indicated that ZnPc effectively generated singlet oxygen induced by the emission from the UCNPs. Cell viability assays showed the low cytotoxicity of the UCNPs after surface modification. In vitro and in vivo therapeutic investigation evidenced the prominent PDT effects of ZnPc-loaded SOC-UCNPs upon NIR light irradiation. Furthermore, NIR imaging of ICG derivative-loaded SOC-UCNPs after intra-tumoral injection indicated the high retention of SOC-UCNPs only in the tumor site. Histological examination confirmed the negligible toxicity of ZnPc-loaded SOC-UCNPs on other organs. All the results demonstrate the promising potential of using SOC-UCNPs as new photosensitizer carriers for PDT of cancer and other diseases in deep tissues.

Ultra-small gold nanoclusters (Au NCs) are highly promising materials for tumor imaging and therapy because of their low toxicity, intrinsic fluorescence, and the availability of multifunctional groups for covalent linkage of diverse bioactive molecules. Au NCs stabilized by bovine serum albumin (BSA) were prepared via an improved "green" synthetic routine. To ameliorate the selective affinity of Au NCs for high folate receptor (FR) expressing tumors, folic acid (FA) was immobilized on the surface of Au NCs. Subsequently, a near-infrared (NIR) fluorescent dye MPA was conjugated with Au-FA NCs for in vitro and in vivo fluorescence imaging. Similarly, Doxorubicin (DOX), a widely used clinical anticancer drug, was also conjugated to the folate-modified Au NCs to form a prodrug (Au-FA-DOX). Cellular and in vivo acute toxicity studies demonstrated the low toxicity of the Au-FA-MPA to normal cells and tissues. Additionally, in vitro and in vivo study of the dynamic behavior and targeting ability of Au-FA-MPA to different tumors validated the high selective affinity of Au-FA-MPA to FR positive tumors. With regard to the Au-FA-DOX, high anti-tumor activity was displayed by this pro-drug due to the FR mediated uptake. Herein, all of the results supported the potential of using ligand-modified Au NCs for tumor imaging and targeted therapy.

Oleic acid-coated upconverting nanoparticles were prepared by hydrothermal and solvothermal synthesis. The properties of as-prepared NaYF4:Yb,Er nanoparticles were characterized, including transmission electron microscope, X-ray diffraction pattern and photoluminescence spectrum. The effects of reaction conditions (reaction time and temperature) and the concentration of rare earth dopants have been investigated in each strategy. Optical properties of upconverting nanoparticles synthesized by two strategies were compared as well. For biological application, the surface ligands were exchanged from oleic acid to hexanedioic acid with carboxyl-functionalized groups. The results indicated upconverting nanospheres (45 ± 2 nm) and nanoplates (150 ± 5 nm) prepared by solvothermal synthesis had higher photoluminescence intensity with uniform size distribution, whereas hydrothermal synthesis produced small upconverting nanocubes (8–20 nm). Upconverting nanoparticles in hydrothermal synthesis showed better optical properties while increasing the reaction time and decreasing the molar ratio of water. The ratio of green and red emissions of NaYF4:Yb,Er nanoparticles could be adjusted through changing the concentration of rare earth dopants. Furthermore, hexanedioic acid mediated ligand-exchange process transferred NaYF4 nanoparticles from hydrophobic to hydrophilic with great potential as biological labels.