THE SPECIFIC PHOTODYNAMIC EFFECTS OF MONOCLONAL ANTIBODIES CONJUGATED WITH HEMATOPORPHYRIN DERIVATIVE ON GASTRIC CANCER IN VITRO AND IN VIVO

Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated with a hematoporphyrin derivative (HPD) by using carbodiimide. The qualitative analysis of this conjugate showed that the amount of free HPD was negligible and there were no IgG aggregates among the conjugates. The conjugate retained both the antibody and photochemical activity of HPD.In vitro, the phototoxic effect of this HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The quality of selective photocytotoxicity was proven by the greater cytotoxi-city this conjugate showed than that of corresponding normal mouse IgG (NIgG) conjugated with HPD. It showed less cytotoxicity to colon cancer cell line B-80 (negative reaction to MoAb BB4.3) than to BGC825. Moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody, but not by another MoAb 3G9, which combines with BGC823 at different binding sites from MoAb BB4.3.Nude mice inoculated with 2 × 10- BGC823 cells were given HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS, respectively then exposed to light. Four out of six animals treated with the HPD-BB4.3 conjugate remained tumor-free for a long period. Although two developed tumors, there was a significant difference between the HPD-BB4.3-treated group and all the control groups in tumor induction time, tumor growth rate, and survival time (p<0.001). The HPD-BB4.3 conjugate inhibited the growth of established tumors by more than 40% in comparison with control groups (p<0.05).

In vitro study of enhanced photodynamic cancer cell killing effect by nanometer-thick gold nanosheets

Photodynamic therapy(PDT)by near-infrared(NIR)irradiation is a promising technique for treating various cancers.Here,we reported the development of free-standing wafer-scale Au nanosheets(NSs)that exhibited an impressive PDT effect.The Au NSs were synthesized by ionic layer epitaxy at the air-water interface with a uniform thickness in the range from 2 to 8.5 nm.These Au NSs were found very effective in generating singlet oxygen under NIR irradiation.In vitro cellular study showed that the Au NSs had very low cytotoxicity and high PDT efficiency due to their uniform 2D morphology.Au NSs could kill cancer cells after 5 min NIR irradiation with little heat generation.This performance is comparable to using 10 times mass loading of Au nanoparticles(NPs).This work suggests that two-dimensional(2D)Au NSs could be a new type of biocompatible nanomaterial for PDT of cancer with an extraordinary photon conversion and cancer cell killing efficiency.

Ti-MOF-based biosafety materials for efficient and long-life disinfection via synergistic photodynamic and photothermal effects

Pathogenic bacterial infection is severely threatening public health globally.The multi-modal antibacterial nanoplatforms could significantly improve the antibacterial efficiency.Here,we report a metal(Ti)-organic framework(MOF)derived nanocarbon(C-Ti-MOF)as a biosafety material for synergistic sterilization of pathogenic bacteria via efficient photodynamic catalysis and robust photothermal effects.The C-Ti-MOF consists of abundant TiO_(2) nanodots embedded in graphitic carbon frameworks.Under visible light irradiation,TiO_(2) nanodots can catalyze H_(2)O_(2) and O_(2) to produce superoxide anion(•O_(2)^(–))and singlet oxygen(1O2),respectively.Meanwhile,under near-infrared irradiation(NIR),C-Ti-MOF can generate massive heat to destroy bacterial membranes.Systematic antibacterial experiments reveal that the C-Ti-MOF nanoagents have a long-lasting and nearly 100%bactericidal ratio at an extremely low dose(0.16 mg/mL),which is much better than the state-of-the-art TiO_(2)(Commercial TiO_(2)(P25),0.64 mg/mL).Furthermore,the C-Ti-MOF can be electrospun into an antibacterial nanofiber membrane via mixing with polymeric matrix for treating bacteriacontaminated wastewater,and the membranes possess integrated antibacterial activity and excellent biocompatibility.Our study demonstrates a promising Ti-MOF-based biosafety material for efficient and long-life disinfection,which may stimulate new research in MOF-related biological applications in various disciplines ranging from water decontaminations to nanotherapeutics.

Recent advances of carbon dots as new antimicrobial agents

Due to the COVID-19 pandemic,many rapid antimicrobial agents have developed intensively.Carbon dots(CDs),a new type of carbon-based nanomaterials,shows great potential against emerging infectious diseases and antimicrobial-resistant infections due to their unique optical properties,excellent biocompatibility,and easy surface modification.With the definition of the CDs structure and properties,synthesis,and characteristic technology improvement,the research on the CDs as antimicrobial agents has made significant progress.However,the lack of high repeatable and exact preparation methods,and the regular antimicrobial activity make it far from practical application.In this review,we summarize the most recent progress and challenges of CDs antimicrobial.First,an overview of the characteristics and properties is given,and the advantage of CDs applied to antimicrobial is further discussed.Then,it focuses on research progress on antimicrobial mechanisms under different conditions,the critical factors affecting their antimicrobial activity,and the practical antimicrobial applications.Finally,the main challenges and future research perspectives of antimicrobial CDs are proposed.

超稳定的碲掺杂碳量子点在细胞保护和光动力学治疗中的应用

由于活性氧(ROS)在人体新陈代谢中起着重要作用,调节细胞内ROS浓度维持水平是不容忽视的,因此开发能够控制活性氧含量的纳米试剂是非常有意义的.本文采用简单有效的水热法制备了碲掺杂碳量子点(Te-CDs).该量子点水溶性好、稳定性高,具有生物相容性,在溶液水平能够消耗H2O2,在光照下能够产生·OH.因此该碳量子点可作为抗氧化剂应用于细胞保护中,也可作为光敏剂应用于光动力治疗,这双重作用在细胞中均取得了良好的效果,并有望与其他药物共同用于多模态肿瘤治疗.