MMP-2 and upconverted UV dual-mediated drug sequential delivery and on-site immobilization for enhanced multidrugresistant cancer therapy

Controlled drug delivery holds great potential for effective tumor treatment owing to the merits of overcoming drug resistance and improving therapeutic efficacy while minimizing systemic toxicity.However,accurate and controllable delivery of chemotherapeutics into tumor tissue with high efficiency remains a huge challenge.Taking advantage of the UV-emitting characteristics of upconversion nanoparticles(UCNPs),herein we for the first time report an MMP-2 enzyme and near infrared(NIR)dual-mediated sequential drug delivery and in-situ immobilization(ENDDI)system that is fabricated by decorating UCNPs with MMP-2 responsive and photocrosslinkable peptide bearing anticancer drug doxorubicin(DOX)for overcoming multidrug resistance.Upon cleavage with tumor-specific MMP-2,the peptide fragment containing a photolabile benzophenone(BP)and DOX could be released and in-situ immobilized within the tumor through the covalent crosslinking reaction between BP and neighboring biomolecules under the excitation of converted UVemission from UCNPs,which remarkably blocks the exocytosis of DOX leading to prolonged drug retention,achieving significant suppression of DOX-resistant breast tumors.Our current dual stimuli-mediated sequential drug delivery and in-situ immobilization represent a generalizable strategy for the effective treatment of multidrug resistant tumors.

Greatly enhanced electro-optic modulation efficiency in titanium in-diffusion PIN-PMN-PT waveguide

Electro-optic modulators,which convert electrical signals onto the transmission light,are key devices in electro-optic modulating systems.Modulation efficiency is one of the most important parameters of an electro-optic modulator,which directly determines the footprint and power consumption of the device.Generally,modulation efficiency strongly depends on the electro-optic response of the crystal.The Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIN-PMN-PT)single crystal with giant electro-optic coefficient(λ_(c))and high transparency indicates the potential to achieve greatly enhanced modulation efficiency.In this study,a prototype PIN-PMN-PT phase modulator was fabricated based on a titanium(Ti)in-diffusion waveguide,which is reported for the first time.The influences of titanium in-diffusion on the composition and domain structure of the PIN-PMN-PT single crystal were studied by transmission electron microscopy(TEM)and piezoelectric force microscopy(PFM),respectively.Finally,a half-wave voltage(V_(π))of 2.3 V was obtained using a device with 6-mm-long(L)electrodes.Furthermore,the electro-optic modulation efficiency(V_(π)L)was calculated as 1.38 V-cm,which was approximately one order of magnitude lower than that of commercial lithium niobate(LiNbO_(3),LN)phase modulators.Such enhanced modulation efficiency indicates more compact device and lower power consumption,which is of great significance for electro-optic modulation systems used in micro-fiber gyroscope,integrated photonic devices,etc.

N-doped carbon quantum dots as fluorescent probes for highly selective and sensitive detection of Fe^3+ ions

To investigate the effect of nitrogen on the photoluminescence properties of carbon quantum dots (CO Ds), N-doped carbon quantum dots (N-CQDs)were synthesized by one-step hydrothermal treatment using biomass tar as the carbon precursor.As an inevitable organic pollutant,the unsaturated bonds in biomass tar,such as carboxylic acids,aldehydes,and aromatics,are favorable for formation of the graphitic carbon lattice.The obtained N-CQDs are spherical with an average particle size of 2.64nm and the crystal lattice spacing is 0.25nm,corresponding to the (100)facet of graphitic carbon.The N-CQDs emit bright blue photoluminescence under 365nm ultraviolet light,and they have excellent water solubility and stability with a high quantum yield of 26.1%.Coordination between the functional groups on the N-CQD surface and Fe^3+ ions is promoted because of the improved electronic properties and surface chemical reactivity caused by N atoms,leading to a significant fluorescence quenching effect of the N-CQDs in the presence of Fe^3+ions with high selectivity and sensitivity.There is a linear relationship between In (Fo/F)and the Fe^3+ concentration in the N-CQD concentration range 0.06-1400μmol/L with a detection limit of 60nmol/L, showing that the N-CQ.Ds have great potential as a fluorescent probe for Fe^3+detection.

Building multipurpose nano-toolkit by rationally decorating NIR-Ⅱ fluorophore to meet the needs of tumor diagnosis and treatment

Phototheranostics have attracted tremendous attention in cancer diagnosis and treatment because of the noninvasiveness and promising effectiveness.Developing advanced phototheranostic agents with long emission wavelength,excellent biocompatibility,great tumor-targeting capability,and efficient therapeutic effect is highly desirable.However,the mutual constraint between imaging and therapeutic functions usually hinders their wide applications in biomedical field.To balance this contradiction,we herein rationally designed and synthesized three novel tumor-targeted NIR-Ⅱ probes(QR-2PEG_(321),QR-2PEG_(1000),and QR-2PEG_(5000)) by conjugating three different chain lengths of PEG onto an integrin α_(v)β_(3)-targeted NIR-Ⅱ heptamethine cyanine fluorophore,respectively.In virtue of the essential amphiphilic characteristics of PEG polymers,these probes display various degree of aggregation in aqueous buffer accompanying with differential NIR-Ⅱ imaging and photothermal(PTT) therapeutic performance.Both in vitro and in vivo results have demonstrated that probe QR-2PEG_(5000) has the best NIR-Ⅱ imaging performance with prominent renal clearance,whereas QR-2PEG_(321)possesses excellent photoacoustic signal as well as PTT effect,which undoubtedly provides a promising toolbox for tumor diagnosis and therapy.We thus envision that these synthesized probes have great potential to be explored as a toolkit for precise diagnosis and treatment of malignant tumors.

OPTIMIZATION OF Ni BIOACCUMULATION BY SYNECHCOCCUS

Influencing factors on bioaccumulation of Ni by Synechcoccus were studied in this paper. The equilibration time of Ni bioaccumulation was about 80 min in aqueous solution. Bioaccumulation quantity reached maximum when mass ratio of Ni to dry weight concentration of Synechcoccus was 16-18%. Bioaccumulation quantity increased with increasing pH. The optimum pH was 9-10 and higher pH led to precipitation of Ni（OH）2. Bioaccumulation quantity was also influenced by temperature and light intensity reaching their optima at 35℃ and 3 000 lx respectively. Bioaccumulation of nonliving algae was larger than that of living algae.

Enhanced U(Ⅵ) bioreduction by alginate-immobilized uranium-reducing bacteria in the presence of carbon nanotubes and anthraquinone-2,6-disulfonate

Uranium-reducing bacteria were immobilized with sodium alginate, anthraquinone-2,6-disulfonate（AQDS）, and carbon nanotubes（CNTs）. The effects of different AQDS-CNTs contents, U（Ⅳ） concentrations, and metal ions on U（Ⅳ） reduction by immobilized beads were examined. Over 97.5% U（Ⅵ）（20 mg/L） was removed in 8 hr when the beads were added to 0.7% AQDS-CNTs, which was higher than that without AQDS-CNTs. This result may be attributed to the enhanced electron transfer by AQDS and CNTs. The reduction of U（Ⅵ） occurred at initial U（Ⅵ） concentrations of 10 to 100 mg/L and increased with increasing AQDS-CNT content from 0.1% to 1%. The presence of Fe（Ⅲ）, Cu（Ⅱ） and Mn（Ⅱ）slightly increased U（Ⅵ） reduction, whereas Cr（Ⅵ）, Ni（Ⅱ）, Pb（Ⅱ）, and Zn（Ⅱ） significantly inhibited U（Ⅵ） reduction. After eight successive incubation-washing cycles or 8 hr of retention time（HRT） for 48 hr of continuous operation, the removal efficiency of uranium was above 90% and 92%, respectively. The results indicate that the AQDS-CNT/AL/cell beads are suitable for the treatment of uranium-containing wastewaters.