A biodegradable semiconducting polymer phototherapeutic agent for safe cancer phototherapy.

Combined photodynamic therapy (PDT) and photothermal therapy (PTT) not only effectively reduce the hypoxic resistance to PDT, but also overcome the heat shock effect to PTT. However, the residual phototherapeutic agents still produce reactive oxygen species (ROS) to damage normal tissue under sunlight after treatment, which induces undesirable side effects to limit their biomedical application. Herein, a facile strategy is proposed to construct a biodegradable semiconducting polymer p-DTT, which is constructed by thieno[3,2-b]thiophene modified diketopyrrolopyrrole and (E)-1,2-bis(5-(trimethylstannyl)thiophen-2-yl)ethene moieties, to avoid the post-treatment side effects of phototherapy. Additionally, p-DTT exhibits strong photoacoustic (PA) for imaging, as well as good ROS production capacity and high photothermal conversion efficiency for synergistic PDT and PTT, which has been confirmed by both in vitro and in vivo results. After phototherapy, p-DTT could be gradually oxidized and degraded by endogenous ClO-, and subsequently lose ROS production and photothermal conversion capacities, which can guarantee the post-treatment safety, and address above key limitation of traditional phototherapy.

Fluorescence-Quenching Lateral Flow Immunoassay for "Turn-On" and Sensitive Detection of Anti-SARS-Cov-2 Neutralizing Antibodies in Human Serum.

The titer of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (NAbs) in the human body is an essential reference for evaluating the acquired protective immunity and resistance to SARS-CoV-2 infection. In this study, a fluorescence-quenching lateral flow immunoassay (FQ-LFIA) is established for quantitative detection of anti-SARS-CoV-2 NAbs in the sera of individuals who are vaccinated or infected within 10 min. The ultrabright aggregation-induced emission properties encapsulated in nanoparticles, AIE490 NP, are applied in the established FQ-LFIA with gold nanoparticles to achieve a fluorescence "turn-on" competitive immunoassay. Under optimized conditions, the FQ-LFIA quantitatively detected 103 positive and 50 negative human serum samples with a limit of detection (LoD) of 1.29 IU mL-1 . A strong correlation is present with the conventional pseudovirus-based virus neutralization test (R2  = 0.9796, P < 0.0001). In contrast, the traditional LFIA with a "turn-off" mode can only achieve a LoD of 11.06 IU mL-1 . The FQ-LFIA showed excellent sensitivity to anti-SARS-CoV-2 NAbs. The intra- and inter-assay precisions of the established method are below 15%. The established FQ-LFIA has promising potential as a rapid and quantitative method for detecting anti-SARS-CoV-2 NAbs. FQ-LFIA can also be used to detect various biomarkers.

Dextran-Cholesterol Carrier Encapsulated Efficient Photosensitizer for the Photodynamic Killing of Cancer Cells.

Selective photodynamic therapy (PDT) for cancer cells is more efficient and much safer. Most selective PDTs are realized by antigene-biomarker or peptide-biomarker interactions. Here, we modified dextran with hydrophobic cholesterol as a photosensitizer carrier to selectively target cancer cells, including colon cancer cells, and fulfilled selective PDT. The photosensitizer was designed with regular Aggregation-Induced Emission (AIE) units, including triphenylamine and 2-(3-cyano-4,5,5-trimethylfuran-2-ylidene)propanedinitrile. The AIE units can help to decrease the quenching effect in the aggregate state. The efficiency of the photosensitizer is further improved via the heavy atom effect after bromination modification. We found that the obtained photosensitizer nanoparticles could selectively target and ablate cancer cells after encapsulation into the dextran-cholesterol carrier. This study indicates that the polysaccharide-based carrier may have potential for cancer-targeting therapy beyond expectations.