Photodynamic therapy (PDT) has been demonstrated to be an effective minimally invasive treatment modality for early esophageal cancer. However, the molecular action in esophageal cancer during PDT is hardly known. EGFR has been known to downregulate in various cancer cells during PDT. In this study, we investigated the effects of Photofrin-mediated PDT on cell death and expression of EGFR in CE48T/VGH (CE48T) esophageal squamous cell carcinoma cells. We found that the photosensitizer Photofrin in the absence of light exposure can downregulate the expression of EGFR at both transcription and translation levels. Higher concentrations of Photofrin results in cytotoxicity whereas lower doses of Photofrin inhibit EGFR expression under dark control without inducing significant cell death. This Photofrin-associated inhibition of EGFR was repeated in lung cancer, cervical cancer, and glioblastoma cells. Another esophageal squamous cell carcinoma cell line CE81T/VGH (CE81T) was found to be resistant to Photofrin-induced inhibition of EGFR as well as to Photofrin-mediated dark toxicity compared with CE48T. The resistance to the cytotoxicity in CE81T cells became insignificant when the Photofrin-treated cells were further irradiated by red light (Photofrin-PDT). We suggest Photofrin modulates the expression of EGFR in cancer cells. However, efficient cell death still requires the combination of Photofrin and light irradiation in esophageal squamous cell carcinoma cells.

Until now, two-dimensional (2D) nanomaterials have been widely studied and applied in the biosensor field. Some of the advantages offered by these 2D materials include large specific surface area, high conductivity, and easy surface modification. This review discusses the use of 2D material in surface plasmon resonance (SPR) biosensor for diagnostic applications. Two-dimensional material reviewed includes graphene and molybdenum disulfide (MoS 2 ). The discussion begins with a brief introduction to the general principles of the SPR biosensor. The discussion continues by explaining the properties and characteristics of each material and its effect on the performance of the SPR biosensor, in particular its sensitivity. This review concludes with some recent applications of graphene- and MoS 2 -based SPR biosensor in diagnostic applications.

Background Due to educational, social and economic reasons, more and more women are delaying childbirth. However, advanced maternal age is associated with several adverse pregnancy outcomes, and in particular a high risk of Down’s syndrome (DS). Hence, it is increasingly important to be able to detect fetal Down’s syndrome (FDS). Methods We developed an effective, highly sensitive, surface plasmon resonance (SPR) biosensor with biochemically amplified responses using carboxyl-molybdenum disulfide (MoS 2 ) film. The use of carboxylic acid as a surface modifier of MoS 2 promoted dispersion and formed specific three-dimensional coordination sites. The carboxylic acid immobilized unmodified antibodies in a way that enhanced the bioaffinity of MoS 2 and preserved biorecognition properties of the SPR sensor surface. Complete antigen pregnancy-associated plasma protein-A2 (PAPP-A2) conjugated with the carboxyl-MoS 2 -modified gold chip to amplify the signal and improve detection sensitivity. This heterostructure interface had a high work function, and thus improved the efficiency of the electric field energy of the surface plasmon. These results provide evidence that the interface electric field improved performance of the SPR biosensor. Results The carboxyl-MoS 2 -based SPR biosensor was used successfully to evaluate PAPP-A2 level for fetal Down’s syndrome screening in maternal serum samples. The detection limit was 0.05 pg/mL, and the linear working range was 0.1 to 1100 pg/mL. The women with an SPR angle >46.57 m° were more closely associated with fetal Down’s syndrome. Once optimized for serum Down’s syndrome screening, an average recovery of 95.2% and relative standard deviation of 8.5% were obtained. Our findings suggest that carboxyl-MoS 2 -based SPR technology may have advantages over conventional ELISA in certain situations. Conclusion Carboxyl-MoS 2 -based SPR biosensors can be used as a new diagnostic technology to respond to the increasing need for fetal Down’s syndrome screening in maternal serum samples. Our results demonstrated that the carboxyl-MoS 2 -based SPR biosensor was capable of determining PAPP-A2 levels with acceptable accuracy and recovery. We hope that this technology will be investigated in diverse clinical trials and in real case applications for screening and early diagnosis in the future.

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