Chemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalently linked CCG-porphyrin composite was designed to possess a short, rigid phenylene spacer between the porphyrin and the CCG. The composite material formed stable dispersions in DMF and the structure was characterized by spectroscopic, thermal, and microscopic measurements. In steady-state photoluminescence spectra, the emission from the porphyrin linked to the CCG was quenched strongly relative to that of the porphyrin reference. Fluorescence lifetime and femtosecond transient absorption measurements of the porphyrin-linked CCG revealed a short-lived porphyrin singlet excited state (38 ps) without yielding the porphyrin radical cation, thereby substantiating the occurrence of energy transfer from the porphyrin excited state to the CCG and subsequent rapid decay of the CCG excited state to the ground state. Consistently, the photocurrent action spectrum of a photoelectrochemical device with a SnO(2) electrode coated with the porphyrin-linked CCG exhibited no photocurrent response from the porphyrin absorption. The results obtained here provide deep insight into the interaction between graphenes and π-conjugated systems in the excited and ground states.

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Fullerene-encapsulating single-walled carbon nanotubes (C(60)@SWNT) linked with porphyrins by a short bridge have been prepared for the first time. Steady state and time-resolved spectroscopies demonstrated the initial formation of an exciplex state, followed by a charge-separated state.

Carbon nanotubes (CNTs) have many interesting properties. In particular, their photohyperthermic effect by near-infrared (NIR) irradiation could be used to kill cancer cells, and could thus be applied in photohyperthermic therapy. However, the solubility of CNTs must be improved before they can be used in biological applications. As DNA is reported to disperse the CNTs in aqueous solution with π-π interactions, we hypothesis that immunostimulatory CpG DNA may also disperse the CNTs in aqueous solution. In this study, we used CpG DNA to disperse single-walled CNTs (SWCNTs) in aqueous solution, in order to combine photohyperthermic effect and immunoactivation together to achieve a more effective cancer therapy. As expected, CpG DNA effectively dispersed the SWCNTs in aqueous solution via the formation of SWCNT/CpG DNA complexes. Moreover, the immunoreactivity of the SWCNT/CpG DNA complexes was investigated. The results showed that intratumoral administration of the SWCNT/CpG DNA complexes in mice enhanced the production level of inflammatory cytokines in tumor tissues. Finally, we evaluated the antitumor effects of the SWCNT/CpG DNA complexes in tumor-bearing mice. The result indicated that intratumoral administration of the SWCNT/CpG DNA complexes combined with NIR irradiation was a more effective approach to prevent the proliferation of tumor growth.

The photoexcitation of the pyrene dimer on graphene resulted in the final formation of a charge-separated state following an exciplex formation, while that of the pyrene monomer on graphene generated the corresponding exciplex solely due to the difference in the electronic coupling between the pyrene and the graphene.