Carbon quantum dots (C-QDs) are becoming a desirable alternative to metal-based QDs and dye probes owing to their high biocompatibility, low toxicity, ease of preparation, and unique photophysical properties. Herein, we describe fluorescence bioimaging of zebrafish using C-QDs as probe in terms of the preparation of C-QDs, zebrafish husbandry, embryo harvesting, and introduction of C-QDs into embryos and larvae by soaking and microinjection. The multicolor of C-QDs was validated with their imaging for zebrafish embryo. The distribution of C-QDs in zebrafish embryos and larvae were successfully observed from their fluorescence emission. the bio-toxicity of C-QDs was tested with zebrafish as model and C-QDs do not interfere to the development of zebrafish embryo. All of the results confirmed the high biocompatibility and low toxicity of C-QDs as imaging probe. The absorption, distribution, metabolism and excretion route (ADME) of C-QDs in zebrafish was revealed by their distribution. Our work provides the useful information for the researchers interested in studying with zebrafish as a model and the applications of C-QDs. The operations related zebrafish are suitable for the study of the toxicity, adverse effects, transport, and biocompatibility of nanomaterials as well as for drug screening with zebrafish as model.

Imaging-guided therapy systems (IGTSs) are revolutionary techniques used in cancer treatment due to their safety and efficiency. IGTSs should have tunable compositions for bioimaging, a suitable size and shape for biotransfer, sufficient channels and/or pores for drug loading, and intrinsic biocompatibility. Here, a biocompatible nanoscale zirconium-porphyrin metal-organic framework (NPMOF)-based IGTS that is prepared using a microemulsion strategy and carefully tuned reaction conditions is reported. A high content of porphyrin (59.8%) allows the achievement of efficient fluorescent imaging and photodynamic therapy (PDT). The 1D channel of the Kagome topology of NPMOFs provides a 109% doxorubicin loading and pH-response smart release for chemotherapy. The fluorescence guiding of the chemotherapy-and-PDT dual system is confirmed by the concentration of NPMOFs at cancer sites after irradiation with a laser and doxorubicin release, while low toxicity is observed in normal tissues. NPMOFs are established as a promising platform for the early diagnosis of cancer and initial therapy.

The combination of multidrug chemotherapy and photothermal therapy (PTT) enhances cancer therapeutic efficacy. Herein, we develop a simple and smart pH/NIR dual-stimulus-responsive degradable mesoporous CoFeO@PDA@ZIF-8 sandwich nanocomposite. The mesoporous CoFeO core acts as T-weighted magnetic resonance (MR) imaging probe, PTT agent, and loading platform of hydrophilic doxorubicin (DOX). A polydopamine (PDA) layer is used to avoid the premature leakage of DOX before arriving at tumor site, enhance PTT efficiency, and facilitate the integration of ZIF-8 (a kind of metal-organic framework). The ZIF-8 shell serves to encapsulate hydrophobic camptothecin (CPT) and as the switch for the pH and NIR stimulation-responsive release of the two drugs. Therefore, T-weighted MR imaging-guided multidrug chemotherapy and PTT synergistic treatment is achieved. Two kinds of anticancer drugs, hydrophilic DOX and hydrophobic CPT, are successfully loaded in CoFeO and ZIF-8, respectively, so no mutual interference between the two drugs exists. A unique two-stage stepwise release process is exhibited for CPT and DOX with an interval of 12 h to improve the anticancer efficacy under the acidic microenvironment of tumor tissue. NIR irradiation achieves the burst drug-release and PTT after laser stimulation, simultaneously. With this smart design, high drug concentration is achieved at the tumor site by quick release, especially for the therapeutic drugs that show nonlinear pharmacokinetics, and PTT is integrated efficiently. Furthermore, negligible biotoxicity and a remarkable synergic antitumor effect of the hybrid nanocomposites are validated by HepG2 cells and tumor-bearing mice as models. Our multidrug delivery-releasing composite improves tumor therapeutic efficiency significantly compared with a single-drug chemotherapy system. The simple multifunctional composite system can be applied as an effective platform for personal nanomedicine with diagnosis, smart drug delivery, and cancer treatment through its remarkable photothermal property and controllable multidrug release.

Chemotherapy remains restricted by its toxic adverse effects and resistance to drugs. The treatment of nitric oxide (NO) combined with imaging-guided physical therapy is a promising alternative for clinical applications. Herein, we report nanoscale metal-organic framework (NMOF) systems to integrate magnetic resonance (MR) imaging, spatiotemporally controllable NO delivery, and photothermal therapy (PTT) as a new means of cancer theranostics. As a proof of concept, the NMOFs are prepared with biocompatible Zr ions and Mn-porphyrin as a bridging ligand. By inserting paramagnetic Mn ions into porphyrin rings, Mn-porphyrin renders the NMOFs strong T-weighted MR contrast capacity and high photothermal conversion for efficient PTT. S-Nitrosothiol (SNO) is conjugated to the surfaces of the NMOFs for heat-sensitive NO generation. Moreover, single near-infrared (NIR) light triggers the controllable NO release and PTT simultaneously for their efficient synergistic therapy with one-step operation. Upon intravenous injection, NMOF-SNO shows effective tumor accumulation as exposed by the MR images of the tumor-bearing mice. When exposed to the NIR laser, the tumors of mice injected with NMOF-SNO are completely inhibited, verifying the efficiency of NMOF-SNO. For the first time, Mn-porphyrin NMOFs are developed to be an effective theranostic system for MR imaging-guided controllable NO release and photothermal synergetic therapy under single NIR irradiation.

To combine flexibility and modifiability towards a more controllable complexity of MOFs, a post-synthetic variable-spacer installation (PVSI) strategy is used to implement kinetic installation/ uninstallation of secondary ligands into/from a robust yet flexible proto-Zr-MOF. This PVSI process features precise positioning of spacers with different length, size, number, and functionality, enabling accurate fixation of successive breathing stages and fine-tuning of pore surface. It shows unprecedented synthetic tailorability to create complicated MOFs in a predictable way for property modification, for example, CO2 and R22 adsorption/separation, thermal/chemical stability, and extended breathing behavior.