Development of photothermal materials which are able to harness sunlight and convert it to thermal energy seems attractive. Besides carbon-based nanomaterials, conjugated polymers are emerging promising photothermal materials but their facile syntheses remain challenging. In this work, by modification of a CBT-Cys click condensation reaction and rational design of the starting materials, we facilely synthesize conjugated polymers poly-2-phenyl-benzobisthiazole (PPBBT) and its dihexyl derivative with good photothermal properties. Under the irradiation of either sunlight-mimicking Xe light or near-infrared laser, we verify that PPBBT has comparable photothermal heating-up speed to that of star material single-wall carbon nanotube. Moreover, PPBBT is used to fabricate water-soluble NPPPBBT nanoparticles which maintain excellent photothermal properties in vitro and photothermal therapy effect on the tumours exposed to laser irradiation. We envision that our synthetic method provides a facile approach to fabricate conjugated polymers for more promising applications in biomedicine or photovoltaics in the near future.

Intact and stable bone reconstruction is ideal for the treatment of periodontal bone destruction but remains challenging. In research, biomaterials are used to encapsulate stem cells or bioactive factors for periodontal bone regeneration, but, to the best of our knowledge, using a supramolecular hydrogel to encapsulate bioactive factors for their sustained release in bone defect areas to promote periodontal bone regeneration has not been reported. Herein, we used a well-studied hydrogelator, NapFFY, to coassemble with SDF-1 and BMP-2 to prepare a supramolecular hydrogel, SDF-1/BMP-2/NapFFY. In vitro and in vivo results indicated that these two bioactive factors were ideally, synchronously, and continuously released from the hydrogel to effectively promote the regeneration and reconstruction of periodontal bone tissues. Specifically, after the bone defect areas were treated with our SDF-1/BMP-2/NapFFY hydrogel for 8 weeks using maxillary critical-sized periodontal bone defect model rats, a superior bone regeneration rate of 56.7% bone volume fraction was achieved in these rats. We anticipate that our SDF-1/BMP-2/NapFFY hydrogel could replace bone transplantation in the clinic for the repair of periodontal bone defects and periodontally accelerated osteogenic orthodontics in the near future.

Photoacoustic (PA) imaging is advantageous for the diagnosis of superficial cancer with high spatial resolution. However, to the best of our knowledge, using an alkaline phosphatase (ALP)-activatable probe for the enhanced PA imaging of tumors has not been reported. In this work, we rationally designed a NIR probe IR775-Phe-Phe-Tyr(H 2 PO 3 )-OH (1P) for PA imaging ALP activity in vitro and in tumor. Under the catalysis of ALP, 1P was efficiently converted to IR775-Phe-Phe-Tyr-OH (1), which self-assembled into the nanoparticles 1-NPs. The formation of 1-NPs induced a 6.4-fold enhancement of the 795 nm PA signal of 1P. In vivo tumor PA imaging results indicated that, compared to that in the ALP inhibitor-treated control group, PA contrast in the experimental group enhanced 2.3 folds at 4 h after 1P injection. By replacing the Phe-Phe-Tyr(H 2 PO 3 )-OH motif in 1P with other enzyme-cleavable ones, we hope that more PA probes could be developed for the precise diagnoses of their corresponding cancers in the near future.

Employing cellular environment for the self-assembly of supramolecular nanofibers for biological applications has been widely explored. But using one precursor to differentiate the extra- and intracellular environments to self-assemble into two different nanofibers remains challenging. With the knowledge that the extracellualr environment of some cancer cells contains large amounts of alkaline phosphatase (ALP) while their intracellular environment is glutathione (GSH)-abundant in mind, we rationally designed a precursor Cys(SEt)-Glu-Tyr(H2PO3)-Phe-Phe-Gly-CBT (1) that can efficiently yield amphiphilic 2 and 2-D to self-assemble into two different nanofibers in hydrogels under the sequential treatment of ALP and GSH. We envision that, by employing a click condensation reaction, this work offers a platform for facilely postmodulation of supramolecular nanofibers, and the versatile precursor 1 could be used to kill two birds with one stone.